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1 /**
2  * \file ssl.h
3  *
4  * \brief SSL/TLS functions.
5  */
6 /*
7  *  Copyright The Mbed TLS Contributors
8  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
9  */
10 #ifndef MBEDTLS_SSL_H
11 #define MBEDTLS_SSL_H
12 #include "mbedtls/platform_util.h"
13 #include "mbedtls/private_access.h"
14 
15 #include "mbedtls/build_info.h"
16 
17 #include "mbedtls/bignum.h"
18 #include "mbedtls/ecp.h"
19 
20 #include "mbedtls/ssl_ciphersuites.h"
21 
22 #if defined(MBEDTLS_X509_CRT_PARSE_C)
23 #include "mbedtls/x509_crt.h"
24 #include "mbedtls/x509_crl.h"
25 #endif
26 
27 #if defined(MBEDTLS_DHM_C)
28 #include "mbedtls/dhm.h"
29 #endif
30 
31 #include "mbedtls/md.h"
32 
33 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_ANY_ENABLED)
34 #include "mbedtls/ecdh.h"
35 #endif
36 
37 #if defined(MBEDTLS_HAVE_TIME)
38 #include "mbedtls/platform_time.h"
39 #endif
40 
41 #include "psa/crypto.h"
42 
43 /*
44  * SSL Error codes
45  */
46 /** A cryptographic operation is in progress. Try again later. */
47 #define MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS                -0x7000
48 /** The requested feature is not available. */
49 #define MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE               -0x7080
50 /** Bad input parameters to function. */
51 #define MBEDTLS_ERR_SSL_BAD_INPUT_DATA                    -0x7100
52 /** Verification of the message MAC failed. */
53 #define MBEDTLS_ERR_SSL_INVALID_MAC                       -0x7180
54 /** An invalid SSL record was received. */
55 #define MBEDTLS_ERR_SSL_INVALID_RECORD                    -0x7200
56 /** The connection indicated an EOF. */
57 #define MBEDTLS_ERR_SSL_CONN_EOF                          -0x7280
58 /** A message could not be parsed due to a syntactic error. */
59 #define MBEDTLS_ERR_SSL_DECODE_ERROR                      -0x7300
60 /* Error space gap */
61 /** No RNG was provided to the SSL module. */
62 #define MBEDTLS_ERR_SSL_NO_RNG                            -0x7400
63 /** No client certification received from the client, but required by the authentication mode. */
64 #define MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE             -0x7480
65 /** Client received an extended server hello containing an unsupported extension */
66 #define MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION             -0x7500
67 /** No ALPN protocols supported that the client advertises */
68 #define MBEDTLS_ERR_SSL_NO_APPLICATION_PROTOCOL           -0x7580
69 /** The own private key or pre-shared key is not set, but needed. */
70 #define MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED              -0x7600
71 /** No CA Chain is set, but required to operate. */
72 #define MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED                 -0x7680
73 /** An unexpected message was received from our peer. */
74 #define MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE                -0x7700
75 /** A fatal alert message was received from our peer. */
76 #define MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE               -0x7780
77 /** No server could be identified matching the client's SNI. */
78 #define MBEDTLS_ERR_SSL_UNRECOGNIZED_NAME                 -0x7800
79 /** The peer notified us that the connection is going to be closed. */
80 #define MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY                 -0x7880
81 /* Error space gap */
82 /* Error space gap */
83 /** Processing of the Certificate handshake message failed. */
84 #define MBEDTLS_ERR_SSL_BAD_CERTIFICATE                   -0x7A00
85 /* Error space gap */
86 /**
87  * Received NewSessionTicket Post Handshake Message.
88  * This error code is experimental and may be changed or removed without notice.
89  */
90 #define MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET       -0x7B00
91 /** Not possible to read early data */
92 #define MBEDTLS_ERR_SSL_CANNOT_READ_EARLY_DATA            -0x7B80
93 /**
94  * Early data has been received as part of an on-going handshake.
95  * This error code can be returned only on server side if and only if early
96  * data has been enabled by means of the mbedtls_ssl_conf_early_data() API.
97  * This error code can then be returned by mbedtls_ssl_handshake(),
98  * mbedtls_ssl_handshake_step(), mbedtls_ssl_read() or mbedtls_ssl_write() if
99  * early data has been received as part of the handshake sequence they
100  * triggered. To read the early data, call mbedtls_ssl_read_early_data().
101  */
102 #define MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA               -0x7C00
103 /** Not possible to write early data */
104 #define MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA           -0x7C80
105 /* Error space gap */
106 /* Error space gap */
107 /* Error space gap */
108 /* Error space gap */
109 /** Cache entry not found */
110 #define MBEDTLS_ERR_SSL_CACHE_ENTRY_NOT_FOUND             -0x7E80
111 /** Memory allocation failed */
112 #define MBEDTLS_ERR_SSL_ALLOC_FAILED                      -0x7F00
113 /** Hardware acceleration function returned with error */
114 #define MBEDTLS_ERR_SSL_HW_ACCEL_FAILED                   -0x7F80
115 /** Hardware acceleration function skipped / left alone data */
116 #define MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH              -0x6F80
117 /** Handshake protocol not within min/max boundaries */
118 #define MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION              -0x6E80
119 /** The handshake negotiation failed. */
120 #define MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE                 -0x6E00
121 /** Session ticket has expired. */
122 #define MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED            -0x6D80
123 /** Public key type mismatch (eg, asked for RSA key exchange and presented EC key) */
124 #define MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH                  -0x6D00
125 /** Unknown identity received (eg, PSK identity) */
126 #define MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY                  -0x6C80
127 /** Internal error (eg, unexpected failure in lower-level module) */
128 #define MBEDTLS_ERR_SSL_INTERNAL_ERROR                    -0x6C00
129 /** A counter would wrap (eg, too many messages exchanged). */
130 #define MBEDTLS_ERR_SSL_COUNTER_WRAPPING                  -0x6B80
131 /** Unexpected message at ServerHello in renegotiation. */
132 #define MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO       -0x6B00
133 /** DTLS client must retry for hello verification */
134 #define MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED             -0x6A80
135 /** A buffer is too small to receive or write a message */
136 #define MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL                  -0x6A00
137 /* Error space gap */
138 /** No data of requested type currently available on underlying transport. */
139 #define MBEDTLS_ERR_SSL_WANT_READ                         -0x6900
140 /** Connection requires a write call. */
141 #define MBEDTLS_ERR_SSL_WANT_WRITE                        -0x6880
142 /** The operation timed out. */
143 #define MBEDTLS_ERR_SSL_TIMEOUT                           -0x6800
144 /** The client initiated a reconnect from the same port. */
145 #define MBEDTLS_ERR_SSL_CLIENT_RECONNECT                  -0x6780
146 /** Record header looks valid but is not expected. */
147 #define MBEDTLS_ERR_SSL_UNEXPECTED_RECORD                 -0x6700
148 /** The alert message received indicates a non-fatal error. */
149 #define MBEDTLS_ERR_SSL_NON_FATAL                         -0x6680
150 /** A field in a message was incorrect or inconsistent with other fields. */
151 #define MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER                 -0x6600
152 /** Internal-only message signaling that further message-processing should be done */
153 #define MBEDTLS_ERR_SSL_CONTINUE_PROCESSING               -0x6580
154 /** The asynchronous operation is not completed yet. */
155 #define MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS                 -0x6500
156 /** Internal-only message signaling that a message arrived early. */
157 #define MBEDTLS_ERR_SSL_EARLY_MESSAGE                     -0x6480
158 /* Error space gap */
159 /* Error space gap */
160 /* Error space gap */
161 /* Error space gap */
162 /* Error space gap */
163 /* Error space gap */
164 /* Error space gap */
165 /* Error space gap */
166 /** An encrypted DTLS-frame with an unexpected CID was received. */
167 #define MBEDTLS_ERR_SSL_UNEXPECTED_CID                    -0x6000
168 /** An operation failed due to an unexpected version or configuration. */
169 #define MBEDTLS_ERR_SSL_VERSION_MISMATCH                  -0x5F00
170 /** Invalid value in SSL config */
171 #define MBEDTLS_ERR_SSL_BAD_CONFIG                        -0x5E80
172 /* Error space gap */
173 /** Attempt to verify a certificate without an expected hostname.
174  * This is usually insecure.
175  *
176  * In TLS clients, when a client authenticates a server through its
177  * certificate, the client normally checks three things:
178  * - the certificate chain must be valid;
179  * - the chain must start from a trusted CA;
180  * - the certificate must cover the server name that is expected by the client.
181  *
182  * Omitting any of these checks is generally insecure, and can allow a
183  * malicious server to impersonate a legitimate server.
184  *
185  * The third check may be safely skipped in some unusual scenarios,
186  * such as networks where eavesdropping is a risk but not active attacks,
187  * or a private PKI where the client equally trusts all servers that are
188  * accredited by the root CA.
189  *
190  * You should call mbedtls_ssl_set_hostname() with the expected server name
191  * before starting a TLS handshake on a client (unless the client is
192  * set up to only use PSK-based authentication, which does not rely on the
193  * host name). If you have determined that server name verification is not
194  * required for security in your scenario, call mbedtls_ssl_set_hostname()
195  * with \p NULL as the server name.
196  *
197  * This error is raised if all of the following conditions are met:
198  *
199  * - A TLS client is configured with the authentication mode
200  *   #MBEDTLS_SSL_VERIFY_REQUIRED (default).
201  * - Certificate authentication is enabled.
202  * - The client does not call mbedtls_ssl_set_hostname().
203  * - The configuration option
204  *   #MBEDTLS_SSL_CLI_ALLOW_WEAK_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME
205  *   is not enabled.
206  */
207 #define MBEDTLS_ERR_SSL_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME  -0x5D80
208 
209 /*
210  * Constants from RFC 8446 for TLS 1.3 PSK modes
211  *
212  * Those are used in the Pre-Shared Key Exchange Modes extension.
213  * See Section 4.2.9 in RFC 8446.
214  */
215 #define MBEDTLS_SSL_TLS1_3_PSK_MODE_PURE  0 /* Pure PSK-based exchange  */
216 #define MBEDTLS_SSL_TLS1_3_PSK_MODE_ECDHE 1 /* PSK+ECDHE-based exchange */
217 
218 /*
219  * TLS 1.3 NamedGroup values
220  *
221  * From RF 8446
222  *    enum {
223  *         // Elliptic Curve Groups (ECDHE)
224  *         secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
225  *         x25519(0x001D), x448(0x001E),
226  *         // Finite Field Groups (DHE)
227  *         ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
228  *         ffdhe6144(0x0103), ffdhe8192(0x0104),
229  *         // Reserved Code Points
230  *         ffdhe_private_use(0x01FC..0x01FF),
231  *         ecdhe_private_use(0xFE00..0xFEFF),
232  *         (0xFFFF)
233  *     } NamedGroup;
234  *
235  */
236 
237 /* Elliptic Curve Groups (ECDHE) */
238 #define MBEDTLS_SSL_IANA_TLS_GROUP_NONE               0
239 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1     0x0012
240 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1     0x0013
241 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1     0x0014
242 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224R1     0x0015
243 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP256K1     0x0016
244 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1     0x0017
245 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1     0x0018
246 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1     0x0019
247 #define MBEDTLS_SSL_IANA_TLS_GROUP_BP256R1       0x001A
248 #define MBEDTLS_SSL_IANA_TLS_GROUP_BP384R1       0x001B
249 #define MBEDTLS_SSL_IANA_TLS_GROUP_BP512R1       0x001C
250 #define MBEDTLS_SSL_IANA_TLS_GROUP_X25519        0x001D
251 #define MBEDTLS_SSL_IANA_TLS_GROUP_X448          0x001E
252 /* Finite Field Groups (DHE) */
253 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048     0x0100
254 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE3072     0x0101
255 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE4096     0x0102
256 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE6144     0x0103
257 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192     0x0104
258 
259 /*
260  * TLS 1.3 Key Exchange Modes
261  *
262  * Mbed TLS internal identifiers for use with the SSL configuration API
263  * mbedtls_ssl_conf_tls13_key_exchange_modes().
264  */
265 
266 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK            (1u << 0)   /*!< Pure-PSK TLS 1.3 key exchange,
267                                                                          *   encompassing both externally agreed PSKs
268                                                                          *   as well as resumption PSKs. */
269 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL      (1u << 1)   /*!< Pure-Ephemeral TLS 1.3 key exchanges,
270                                                                          *   including for example ECDHE and DHE
271                                                                          *   key exchanges. */
272 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL  (1u << 2)   /*!< PSK-Ephemeral TLS 1.3 key exchanges,
273                                                                          *   using both a PSK and an ephemeral
274                                                                          *   key exchange. */
275 
276 /* Convenience macros for sets of key exchanges. */
277 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_ALL                         \
278     (MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK              |            \
279      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL    |            \
280      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL)          /*!< All TLS 1.3 key exchanges           */
281 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL                     \
282     (MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK              |            \
283      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL)      /*!< All PSK-based TLS 1.3 key exchanges */
284 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ALL               \
285     (MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL        |            \
286      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL)      /*!< All ephemeral TLS 1.3 key exchanges */
287 
288 #define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE   (0)
289 
290 /*
291  * Various constants
292  */
293 
294 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
295 /* These are the high and low bytes of ProtocolVersion as defined by:
296  * - RFC 5246: ProtocolVersion version = { 3, 3 };     // TLS v1.2
297  * - RFC 8446: see section 4.2.1
298  */
299 #define MBEDTLS_SSL_MAJOR_VERSION_3             3
300 #define MBEDTLS_SSL_MINOR_VERSION_3             3   /*!< TLS v1.2 */
301 #define MBEDTLS_SSL_MINOR_VERSION_4             4   /*!< TLS v1.3 */
302 #endif /* MBEDTLS_DEPRECATED_REMOVED */
303 
304 #define MBEDTLS_SSL_TRANSPORT_STREAM            0   /*!< TLS      */
305 #define MBEDTLS_SSL_TRANSPORT_DATAGRAM          1   /*!< DTLS     */
306 
307 #define MBEDTLS_SSL_MAX_HOST_NAME_LEN           255 /*!< Maximum host name defined in RFC 1035 */
308 #define MBEDTLS_SSL_MAX_ALPN_NAME_LEN           255 /*!< Maximum size in bytes of a protocol name in alpn ext., RFC 7301 */
309 
310 #define MBEDTLS_SSL_MAX_ALPN_LIST_LEN           65535 /*!< Maximum size in bytes of list in alpn ext., RFC 7301          */
311 
312 /* RFC 6066 section 4, see also mfl_code_to_length in ssl_tls.c
313  * NONE must be zero so that memset()ing structure to zero works */
314 #define MBEDTLS_SSL_MAX_FRAG_LEN_NONE           0   /*!< don't use this extension   */
315 #define MBEDTLS_SSL_MAX_FRAG_LEN_512            1   /*!< MaxFragmentLength 2^9      */
316 #define MBEDTLS_SSL_MAX_FRAG_LEN_1024           2   /*!< MaxFragmentLength 2^10     */
317 #define MBEDTLS_SSL_MAX_FRAG_LEN_2048           3   /*!< MaxFragmentLength 2^11     */
318 #define MBEDTLS_SSL_MAX_FRAG_LEN_4096           4   /*!< MaxFragmentLength 2^12     */
319 #define MBEDTLS_SSL_MAX_FRAG_LEN_INVALID        5   /*!< first invalid value        */
320 
321 #define MBEDTLS_SSL_IS_CLIENT                   0
322 #define MBEDTLS_SSL_IS_SERVER                   1
323 
324 #define MBEDTLS_SSL_EXTENDED_MS_DISABLED        0
325 #define MBEDTLS_SSL_EXTENDED_MS_ENABLED         1
326 
327 #define MBEDTLS_SSL_CID_DISABLED                0
328 #define MBEDTLS_SSL_CID_ENABLED                 1
329 
330 #define MBEDTLS_SSL_ETM_DISABLED                0
331 #define MBEDTLS_SSL_ETM_ENABLED                 1
332 
333 #define MBEDTLS_SSL_COMPRESS_NULL               0
334 
335 #define MBEDTLS_SSL_VERIFY_NONE                 0
336 #define MBEDTLS_SSL_VERIFY_OPTIONAL             1
337 #define MBEDTLS_SSL_VERIFY_REQUIRED             2
338 #define MBEDTLS_SSL_VERIFY_UNSET                3 /* Used only for sni_authmode */
339 
340 #define MBEDTLS_SSL_LEGACY_RENEGOTIATION        0
341 #define MBEDTLS_SSL_SECURE_RENEGOTIATION        1
342 
343 #define MBEDTLS_SSL_RENEGOTIATION_DISABLED      0
344 #define MBEDTLS_SSL_RENEGOTIATION_ENABLED       1
345 
346 #define MBEDTLS_SSL_ANTI_REPLAY_DISABLED        0
347 #define MBEDTLS_SSL_ANTI_REPLAY_ENABLED         1
348 
349 #define MBEDTLS_SSL_RENEGOTIATION_NOT_ENFORCED  -1
350 #define MBEDTLS_SSL_RENEGO_MAX_RECORDS_DEFAULT  16
351 
352 #define MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION     0
353 #define MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION  1
354 #define MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE      2
355 
356 #define MBEDTLS_SSL_TRUNC_HMAC_DISABLED         0
357 #define MBEDTLS_SSL_TRUNC_HMAC_ENABLED          1
358 #define MBEDTLS_SSL_TRUNCATED_HMAC_LEN          10  /* 80 bits, rfc 6066 section 7 */
359 
360 #define MBEDTLS_SSL_SESSION_TICKETS_DISABLED     0
361 #define MBEDTLS_SSL_SESSION_TICKETS_ENABLED      1
362 
363 #define MBEDTLS_SSL_PRESET_DEFAULT              0
364 #define MBEDTLS_SSL_PRESET_SUITEB               2
365 
366 #define MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED       1
367 #define MBEDTLS_SSL_CERT_REQ_CA_LIST_DISABLED      0
368 
369 #define MBEDTLS_SSL_EARLY_DATA_DISABLED        0
370 #define MBEDTLS_SSL_EARLY_DATA_ENABLED         1
371 
372 #define MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED    0
373 #define MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED      1
374 
375 #define MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_CLIENT  1
376 #define MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_SERVER  0
377 
378 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
379 #if defined(PSA_WANT_ALG_SHA_384)
380 #define MBEDTLS_SSL_TLS1_3_TICKET_RESUMPTION_KEY_LEN        48
381 #elif defined(PSA_WANT_ALG_SHA_256)
382 #define MBEDTLS_SSL_TLS1_3_TICKET_RESUMPTION_KEY_LEN        32
383 #endif
384 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
385 /*
386  * Default range for DTLS retransmission timer value, in milliseconds.
387  * RFC 6347 4.2.4.1 says from 1 second to 60 seconds.
388  */
389 #define MBEDTLS_SSL_DTLS_TIMEOUT_DFL_MIN    1000
390 #define MBEDTLS_SSL_DTLS_TIMEOUT_DFL_MAX   60000
391 
392 /*
393  * Whether early data record should be discarded or not and how.
394  *
395  * The client has indicated early data and the server has rejected them.
396  * The server has then to skip past early data by either:
397  * - attempting to deprotect received records using the handshake traffic
398  *   key, discarding records which fail deprotection (up to the configured
399  *   max_early_data_size). Once a record is deprotected successfully,
400  *   it is treated as the start of the client's second flight and the
401  *   server proceeds as with an ordinary 1-RTT handshake.
402  * - skipping all records with an external content type of
403  *   "application_data" (indicating that they are encrypted), up to the
404  *   configured max_early_data_size. This is the expected behavior if the
405  *   server has sent an HelloRetryRequest message. The server ignores
406  *   application data message before 2nd ClientHello.
407  */
408 #define MBEDTLS_SSL_EARLY_DATA_NO_DISCARD 0
409 #define MBEDTLS_SSL_EARLY_DATA_TRY_TO_DEPROTECT_AND_DISCARD 1
410 #define MBEDTLS_SSL_EARLY_DATA_DISCARD 2
411 
412 /**
413  * \name SECTION: Module settings
414  *
415  * The configuration options you can set for this module are in this section.
416  * Either change them in mbedtls_config.h or define them on the compiler command line.
417  * \{
418  */
419 
420 /*
421  * Maximum fragment length in bytes,
422  * determines the size of each of the two internal I/O buffers.
423  *
424  * Note: the RFC defines the default size of SSL / TLS messages. If you
425  * change the value here, other clients / servers may not be able to
426  * communicate with you anymore. Only change this value if you control
427  * both sides of the connection and have it reduced at both sides, or
428  * if you're using the Max Fragment Length extension and you know all your
429  * peers are using it too!
430  */
431 #if !defined(MBEDTLS_SSL_IN_CONTENT_LEN)
432 #define MBEDTLS_SSL_IN_CONTENT_LEN 16384
433 #endif
434 
435 #if !defined(MBEDTLS_SSL_OUT_CONTENT_LEN)
436 #define MBEDTLS_SSL_OUT_CONTENT_LEN 16384
437 #endif
438 
439 /*
440  * Maximum number of heap-allocated bytes for the purpose of
441  * DTLS handshake message reassembly and future message buffering.
442  */
443 #if !defined(MBEDTLS_SSL_DTLS_MAX_BUFFERING)
444 #define MBEDTLS_SSL_DTLS_MAX_BUFFERING 32768
445 #endif
446 
447 /*
448  * Maximum length of CIDs for incoming and outgoing messages.
449  */
450 #if !defined(MBEDTLS_SSL_CID_IN_LEN_MAX)
451 #define MBEDTLS_SSL_CID_IN_LEN_MAX          32
452 #endif
453 
454 #if !defined(MBEDTLS_SSL_CID_OUT_LEN_MAX)
455 #define MBEDTLS_SSL_CID_OUT_LEN_MAX         32
456 #endif
457 
458 #if !defined(MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY)
459 #define MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 16
460 #endif
461 
462 #if !defined(MBEDTLS_SSL_MAX_EARLY_DATA_SIZE)
463 #define MBEDTLS_SSL_MAX_EARLY_DATA_SIZE        1024
464 #endif
465 
466 #if !defined(MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE)
467 #define MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE 6000
468 #endif
469 
470 #if !defined(MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH)
471 #define MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH 32
472 #endif
473 
474 #if !defined(MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS)
475 #define MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS 1
476 #endif
477 
478 /** \} name SECTION: Module settings */
479 
480 /*
481  * Default to standard CID mode
482  */
483 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) && \
484     !defined(MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT)
485 #define MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT 0
486 #endif
487 
488 /*
489  * Length of the verify data for secure renegotiation
490  */
491 #define MBEDTLS_SSL_VERIFY_DATA_MAX_LEN 12
492 
493 /*
494  * Signaling ciphersuite values (SCSV)
495  */
496 #define MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO    0xFF   /**< renegotiation info ext */
497 
498 /*
499  * Supported Signature and Hash algorithms (For TLS 1.2)
500  * RFC 5246 section 7.4.1.4.1
501  */
502 #define MBEDTLS_SSL_HASH_NONE                0
503 #define MBEDTLS_SSL_HASH_MD5                 1
504 #define MBEDTLS_SSL_HASH_SHA1                2
505 #define MBEDTLS_SSL_HASH_SHA224              3
506 #define MBEDTLS_SSL_HASH_SHA256              4
507 #define MBEDTLS_SSL_HASH_SHA384              5
508 #define MBEDTLS_SSL_HASH_SHA512              6
509 
510 #define MBEDTLS_SSL_SIG_ANON                 0
511 #define MBEDTLS_SSL_SIG_RSA                  1
512 #define MBEDTLS_SSL_SIG_ECDSA                3
513 
514 /*
515  * TLS 1.3 signature algorithms
516  * RFC 8446, Section 4.2.3
517  */
518 
519 /* RSASSA-PKCS1-v1_5 algorithms */
520 #define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA256 0x0401
521 #define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA384 0x0501
522 #define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA512 0x0601
523 
524 /* ECDSA algorithms */
525 #define MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256 0x0403
526 #define MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384 0x0503
527 #define MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512 0x0603
528 
529 /* RSASSA-PSS algorithms with public key OID rsaEncryption */
530 #define MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256 0x0804
531 #define MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384 0x0805
532 #define MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512 0x0806
533 
534 /* EdDSA algorithms */
535 #define MBEDTLS_TLS1_3_SIG_ED25519 0x0807
536 #define MBEDTLS_TLS1_3_SIG_ED448 0x0808
537 
538 /* RSASSA-PSS algorithms with public key OID RSASSA-PSS  */
539 #define MBEDTLS_TLS1_3_SIG_RSA_PSS_PSS_SHA256 0x0809
540 #define MBEDTLS_TLS1_3_SIG_RSA_PSS_PSS_SHA384 0x080A
541 #define MBEDTLS_TLS1_3_SIG_RSA_PSS_PSS_SHA512 0x080B
542 
543 /* LEGACY ALGORITHMS */
544 #define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA1 0x0201
545 #define MBEDTLS_TLS1_3_SIG_ECDSA_SHA1     0x0203
546 
547 #define MBEDTLS_TLS1_3_SIG_NONE 0x0
548 
549 /*
550  * Client Certificate Types
551  * RFC 5246 section 7.4.4 plus RFC 4492 section 5.5
552  */
553 #define MBEDTLS_SSL_CERT_TYPE_RSA_SIGN       1
554 #define MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN    64
555 
556 /*
557  * Message, alert and handshake types
558  */
559 #define MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC     20
560 #define MBEDTLS_SSL_MSG_ALERT                  21
561 #define MBEDTLS_SSL_MSG_HANDSHAKE              22
562 #define MBEDTLS_SSL_MSG_APPLICATION_DATA       23
563 #define MBEDTLS_SSL_MSG_CID                    25
564 
565 #define MBEDTLS_SSL_ALERT_LEVEL_WARNING         1
566 #define MBEDTLS_SSL_ALERT_LEVEL_FATAL           2
567 
568 #define MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY           0  /* 0x00 */
569 #define MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE    10  /* 0x0A */
570 #define MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC        20  /* 0x14 */
571 #define MBEDTLS_SSL_ALERT_MSG_DECRYPTION_FAILED     21  /* 0x15 */
572 #define MBEDTLS_SSL_ALERT_MSG_RECORD_OVERFLOW       22  /* 0x16 */
573 #define MBEDTLS_SSL_ALERT_MSG_DECOMPRESSION_FAILURE 30  /* 0x1E */
574 #define MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE     40  /* 0x28 */
575 #define MBEDTLS_SSL_ALERT_MSG_NO_CERT               41  /* 0x29 */
576 #define MBEDTLS_SSL_ALERT_MSG_BAD_CERT              42  /* 0x2A */
577 #define MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT      43  /* 0x2B */
578 #define MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED          44  /* 0x2C */
579 #define MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED          45  /* 0x2D */
580 #define MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN          46  /* 0x2E */
581 #define MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER     47  /* 0x2F */
582 #define MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA            48  /* 0x30 */
583 #define MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED         49  /* 0x31 */
584 #define MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR          50  /* 0x32 */
585 #define MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR         51  /* 0x33 */
586 #define MBEDTLS_SSL_ALERT_MSG_EXPORT_RESTRICTION    60  /* 0x3C */
587 #define MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION      70  /* 0x46 */
588 #define MBEDTLS_SSL_ALERT_MSG_INSUFFICIENT_SECURITY 71  /* 0x47 */
589 #define MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR        80  /* 0x50 */
590 #define MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK 86  /* 0x56 */
591 #define MBEDTLS_SSL_ALERT_MSG_USER_CANCELED         90  /* 0x5A */
592 #define MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION     100  /* 0x64 */
593 #define MBEDTLS_SSL_ALERT_MSG_MISSING_EXTENSION    109  /* 0x6d -- new in TLS 1.3 */
594 #define MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT      110  /* 0x6E */
595 #define MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME    112  /* 0x70 */
596 #define MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY 115  /* 0x73 */
597 #define MBEDTLS_SSL_ALERT_MSG_CERT_REQUIRED        116  /* 0x74 */
598 #define MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL 120 /* 0x78 */
599 
600 #define MBEDTLS_SSL_HS_HELLO_REQUEST            0
601 #define MBEDTLS_SSL_HS_CLIENT_HELLO             1
602 #define MBEDTLS_SSL_HS_SERVER_HELLO             2
603 #define MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST     3
604 #define MBEDTLS_SSL_HS_NEW_SESSION_TICKET       4
605 #define MBEDTLS_SSL_HS_END_OF_EARLY_DATA        5
606 #define MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS     8
607 #define MBEDTLS_SSL_HS_CERTIFICATE             11
608 #define MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE     12
609 #define MBEDTLS_SSL_HS_CERTIFICATE_REQUEST     13
610 #define MBEDTLS_SSL_HS_SERVER_HELLO_DONE       14
611 #define MBEDTLS_SSL_HS_CERTIFICATE_VERIFY      15
612 #define MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE     16
613 #define MBEDTLS_SSL_HS_FINISHED                20
614 #define MBEDTLS_SSL_HS_MESSAGE_HASH           254
615 
616 /*
617  * TLS extensions
618  */
619 #define MBEDTLS_TLS_EXT_SERVERNAME                   0
620 #define MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME          0
621 
622 #define MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH          1
623 
624 #define MBEDTLS_TLS_EXT_TRUNCATED_HMAC               4
625 #define MBEDTLS_TLS_EXT_STATUS_REQUEST               5 /* RFC 6066 TLS 1.2 and 1.3 */
626 
627 #define MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES   10
628 #define MBEDTLS_TLS_EXT_SUPPORTED_GROUPS            10 /* RFC 8422,7919 TLS 1.2 and 1.3 */
629 #define MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS     11
630 
631 #define MBEDTLS_TLS_EXT_SIG_ALG                     13 /* RFC 8446 TLS 1.3 */
632 #define MBEDTLS_TLS_EXT_USE_SRTP                    14
633 #define MBEDTLS_TLS_EXT_HEARTBEAT                   15 /* RFC 6520 TLS 1.2 and 1.3 */
634 #define MBEDTLS_TLS_EXT_ALPN                        16
635 
636 #define MBEDTLS_TLS_EXT_SCT                         18 /* RFC 6962 TLS 1.2 and 1.3 */
637 #define MBEDTLS_TLS_EXT_CLI_CERT_TYPE               19 /* RFC 7250 TLS 1.2 and 1.3 */
638 #define MBEDTLS_TLS_EXT_SERV_CERT_TYPE              20 /* RFC 7250 TLS 1.2 and 1.3 */
639 #define MBEDTLS_TLS_EXT_PADDING                     21 /* RFC 7685 TLS 1.2 and 1.3 */
640 #define MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC            22 /* 0x16 */
641 #define MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET  0x0017 /* 23 */
642 
643 #define MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT           28 /* RFC 8449 (implemented for TLS 1.3 only) */
644 
645 #define MBEDTLS_TLS_EXT_SESSION_TICKET              35
646 
647 #define MBEDTLS_TLS_EXT_PRE_SHARED_KEY              41 /* RFC 8446 TLS 1.3 */
648 #define MBEDTLS_TLS_EXT_EARLY_DATA                  42 /* RFC 8446 TLS 1.3 */
649 #define MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS          43 /* RFC 8446 TLS 1.3 */
650 #define MBEDTLS_TLS_EXT_COOKIE                      44 /* RFC 8446 TLS 1.3 */
651 #define MBEDTLS_TLS_EXT_PSK_KEY_EXCHANGE_MODES      45 /* RFC 8446 TLS 1.3 */
652 
653 #define MBEDTLS_TLS_EXT_CERT_AUTH                   47 /* RFC 8446 TLS 1.3 */
654 #define MBEDTLS_TLS_EXT_OID_FILTERS                 48 /* RFC 8446 TLS 1.3 */
655 #define MBEDTLS_TLS_EXT_POST_HANDSHAKE_AUTH         49 /* RFC 8446 TLS 1.3 */
656 #define MBEDTLS_TLS_EXT_SIG_ALG_CERT                50 /* RFC 8446 TLS 1.3 */
657 #define MBEDTLS_TLS_EXT_KEY_SHARE                   51 /* RFC 8446 TLS 1.3 */
658 
659 #if MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT == 0
660 #define MBEDTLS_TLS_EXT_CID                         54 /* RFC 9146 DTLS 1.2 CID */
661 #else
662 #define MBEDTLS_TLS_EXT_CID                        254 /* Pre-RFC 9146 DTLS 1.2 CID */
663 #endif
664 
665 #define MBEDTLS_TLS_EXT_ECJPAKE_KKPP               256 /* experimental */
666 
667 #define MBEDTLS_TLS_EXT_RENEGOTIATION_INFO      0xFF01
668 
669 /*
670  * Size defines
671  */
672 #if !defined(MBEDTLS_PSK_MAX_LEN)
673 /*
674  * If the library supports TLS 1.3 tickets and the cipher suite
675  * TLS1-3-AES-256-GCM-SHA384, set the PSK maximum length to 48 instead of 32.
676  * That way, the TLS 1.3 client and server are able to resume sessions where
677  * the cipher suite is TLS1-3-AES-256-GCM-SHA384 (pre-shared keys are 48
678  * bytes long in that case).
679  */
680 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
681     defined(MBEDTLS_SSL_SESSION_TICKETS) && \
682     defined(MBEDTLS_SSL_HAVE_AES) && defined(MBEDTLS_SSL_HAVE_GCM) && \
683     defined(MBEDTLS_MD_CAN_SHA384)
684 #define MBEDTLS_PSK_MAX_LEN 48 /* 384 bits */
685 #else
686 #define MBEDTLS_PSK_MAX_LEN 32 /* 256 bits */
687 #endif
688 #endif /* !MBEDTLS_PSK_MAX_LEN */
689 
690 /* Dummy type used only for its size */
691 union mbedtls_ssl_premaster_secret {
692     unsigned char dummy; /* Make the union non-empty even with SSL disabled */
693 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
694     unsigned char _pms_rsa[48];                         /* RFC 5246 8.1.1 */
695 #endif
696 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
697     unsigned char _pms_dhm[MBEDTLS_MPI_MAX_SIZE];      /* RFC 5246 8.1.2 */
698 #endif
699 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED)    || \
700     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)  || \
701     defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)     || \
702     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
703     unsigned char _pms_ecdh[MBEDTLS_ECP_MAX_BYTES];    /* RFC 4492 5.10 */
704 #endif
705 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
706     unsigned char _pms_psk[4 + 2 * MBEDTLS_PSK_MAX_LEN];       /* RFC 4279 2 */
707 #endif
708 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
709     unsigned char _pms_dhe_psk[4 + MBEDTLS_MPI_MAX_SIZE
710                                + MBEDTLS_PSK_MAX_LEN];         /* RFC 4279 3 */
711 #endif
712 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
713     unsigned char _pms_rsa_psk[52 + MBEDTLS_PSK_MAX_LEN];      /* RFC 4279 4 */
714 #endif
715 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
716     unsigned char _pms_ecdhe_psk[4 + MBEDTLS_ECP_MAX_BYTES
717                                  + MBEDTLS_PSK_MAX_LEN];       /* RFC 5489 2 */
718 #endif
719 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
720     unsigned char _pms_ecjpake[32];     /* Thread spec: SHA-256 output */
721 #endif
722 };
723 
724 #define MBEDTLS_PREMASTER_SIZE     sizeof(union mbedtls_ssl_premaster_secret)
725 
726 #define MBEDTLS_TLS1_3_MD_MAX_SIZE         PSA_HASH_MAX_SIZE
727 
728 
729 /* Length in number of bytes of the TLS sequence number */
730 #define MBEDTLS_SSL_SEQUENCE_NUMBER_LEN 8
731 
732 #ifdef __cplusplus
733 extern "C" {
734 #endif
735 
736 /*
737  * SSL state machine
738  */
739 typedef enum {
740     MBEDTLS_SSL_HELLO_REQUEST,
741     MBEDTLS_SSL_CLIENT_HELLO,
742     MBEDTLS_SSL_SERVER_HELLO,
743     MBEDTLS_SSL_SERVER_CERTIFICATE,
744     MBEDTLS_SSL_SERVER_KEY_EXCHANGE,
745     MBEDTLS_SSL_CERTIFICATE_REQUEST,
746     MBEDTLS_SSL_SERVER_HELLO_DONE,
747     MBEDTLS_SSL_CLIENT_CERTIFICATE,
748     MBEDTLS_SSL_CLIENT_KEY_EXCHANGE,
749     MBEDTLS_SSL_CERTIFICATE_VERIFY,
750     MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC,
751     MBEDTLS_SSL_CLIENT_FINISHED,
752     MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC,
753     MBEDTLS_SSL_SERVER_FINISHED,
754     MBEDTLS_SSL_FLUSH_BUFFERS,
755     MBEDTLS_SSL_HANDSHAKE_WRAPUP,
756     MBEDTLS_SSL_NEW_SESSION_TICKET,
757     MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT,
758     MBEDTLS_SSL_HELLO_RETRY_REQUEST,
759     MBEDTLS_SSL_ENCRYPTED_EXTENSIONS,
760     MBEDTLS_SSL_END_OF_EARLY_DATA,
761     MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY,
762     MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED,
763     MBEDTLS_SSL_CLIENT_CCS_BEFORE_2ND_CLIENT_HELLO,
764     MBEDTLS_SSL_SERVER_CCS_AFTER_SERVER_HELLO,
765     MBEDTLS_SSL_CLIENT_CCS_AFTER_CLIENT_HELLO,
766     MBEDTLS_SSL_SERVER_CCS_AFTER_HELLO_RETRY_REQUEST,
767     MBEDTLS_SSL_HANDSHAKE_OVER,
768     MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET,
769     MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET_FLUSH,
770 }
771 mbedtls_ssl_states;
772 
773 /*
774  * Early data status, client side only.
775  */
776 
777 #if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_CLI_C)
778 typedef enum {
779 /*
780  * See documentation of mbedtls_ssl_get_early_data_status().
781  */
782     MBEDTLS_SSL_EARLY_DATA_STATUS_NOT_INDICATED,
783     MBEDTLS_SSL_EARLY_DATA_STATUS_ACCEPTED,
784     MBEDTLS_SSL_EARLY_DATA_STATUS_REJECTED,
785 } mbedtls_ssl_early_data_status;
786 #endif /* MBEDTLS_SSL_EARLY_DATA && MBEDTLS_SSL_CLI_C */
787 
788 /**
789  * \brief          Callback type: send data on the network.
790  *
791  * \note           That callback may be either blocking or non-blocking.
792  *
793  * \param ctx      Context for the send callback (typically a file descriptor)
794  * \param buf      Buffer holding the data to send
795  * \param len      Length of the data to send
796  *
797  * \return         The callback must return the number of bytes sent if any,
798  *                 or a non-zero error code.
799  *                 If performing non-blocking I/O, \c MBEDTLS_ERR_SSL_WANT_WRITE
800  *                 must be returned when the operation would block.
801  *
802  * \note           The callback is allowed to send fewer bytes than requested.
803  *                 It must always return the number of bytes actually sent.
804  */
805 typedef int mbedtls_ssl_send_t(void *ctx,
806                                const unsigned char *buf,
807                                size_t len);
808 
809 /**
810  * \brief          Callback type: receive data from the network.
811  *
812  * \note           That callback may be either blocking or non-blocking.
813  *
814  * \param ctx      Context for the receive callback (typically a file
815  *                 descriptor)
816  * \param buf      Buffer to write the received data to
817  * \param len      Length of the receive buffer
818  *
819  * \returns        If data has been received, the positive number of bytes received.
820  * \returns        \c 0 if the connection has been closed.
821  * \returns        If performing non-blocking I/O, \c MBEDTLS_ERR_SSL_WANT_READ
822  *                 must be returned when the operation would block.
823  * \returns        Another negative error code on other kinds of failures.
824  *
825  * \note           The callback may receive fewer bytes than the length of the
826  *                 buffer. It must always return the number of bytes actually
827  *                 received and written to the buffer.
828  */
829 typedef int mbedtls_ssl_recv_t(void *ctx,
830                                unsigned char *buf,
831                                size_t len);
832 
833 /**
834  * \brief          Callback type: receive data from the network, with timeout
835  *
836  * \note           That callback must block until data is received, or the
837  *                 timeout delay expires, or the operation is interrupted by a
838  *                 signal.
839  *
840  * \param ctx      Context for the receive callback (typically a file descriptor)
841  * \param buf      Buffer to write the received data to
842  * \param len      Length of the receive buffer
843  * \param timeout  Maximum number of milliseconds to wait for data
844  *                 0 means no timeout (potentially waiting forever)
845  *
846  * \return         The callback must return the number of bytes received,
847  *                 or a non-zero error code:
848  *                 \c MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
849  *                 \c MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
850  *
851  * \note           The callback may receive fewer bytes than the length of the
852  *                 buffer. It must always return the number of bytes actually
853  *                 received and written to the buffer.
854  */
855 typedef int mbedtls_ssl_recv_timeout_t(void *ctx,
856                                        unsigned char *buf,
857                                        size_t len,
858                                        uint32_t timeout);
859 /**
860  * \brief          Callback type: set a pair of timers/delays to watch
861  *
862  * \param ctx      Context pointer
863  * \param int_ms   Intermediate delay in milliseconds
864  * \param fin_ms   Final delay in milliseconds
865  *                 0 cancels the current timer.
866  *
867  * \note           This callback must at least store the necessary information
868  *                 for the associated \c mbedtls_ssl_get_timer_t callback to
869  *                 return correct information.
870  *
871  * \note           If using an event-driven style of programming, an event must
872  *                 be generated when the final delay is passed. The event must
873  *                 cause a call to \c mbedtls_ssl_handshake() with the proper
874  *                 SSL context to be scheduled. Care must be taken to ensure
875  *                 that at most one such call happens at a time.
876  *
877  * \note           Only one timer at a time must be running. Calling this
878  *                 function while a timer is running must cancel it. Cancelled
879  *                 timers must not generate any event.
880  */
881 typedef void mbedtls_ssl_set_timer_t(void *ctx,
882                                      uint32_t int_ms,
883                                      uint32_t fin_ms);
884 
885 /**
886  * \brief          Callback type: get status of timers/delays
887  *
888  * \param ctx      Context pointer
889  *
890  * \return         This callback must return:
891  *                 -1 if cancelled (fin_ms == 0),
892  *                  0 if none of the delays have passed,
893  *                  1 if only the intermediate delay has passed,
894  *                  2 if the final delay has passed.
895  */
896 typedef int mbedtls_ssl_get_timer_t(void *ctx);
897 
898 /* Defined below */
899 typedef struct mbedtls_ssl_session mbedtls_ssl_session;
900 typedef struct mbedtls_ssl_context mbedtls_ssl_context;
901 typedef struct mbedtls_ssl_config  mbedtls_ssl_config;
902 
903 /* Defined in library/ssl_misc.h */
904 typedef struct mbedtls_ssl_transform mbedtls_ssl_transform;
905 typedef struct mbedtls_ssl_handshake_params mbedtls_ssl_handshake_params;
906 typedef struct mbedtls_ssl_sig_hash_set_t mbedtls_ssl_sig_hash_set_t;
907 #if defined(MBEDTLS_X509_CRT_PARSE_C)
908 typedef struct mbedtls_ssl_key_cert mbedtls_ssl_key_cert;
909 #endif
910 #if defined(MBEDTLS_SSL_PROTO_DTLS)
911 typedef struct mbedtls_ssl_flight_item mbedtls_ssl_flight_item;
912 #endif
913 
914 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
915 #define MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_RESUMPTION                          \
916     MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK                        /* 1U << 0 */
917 #define MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_EPHEMERAL_RESUMPTION                \
918     MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL              /* 1U << 2 */
919 #define MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_EARLY_DATA                  (1U << 3)
920 
921 #define MBEDTLS_SSL_TLS1_3_TICKET_FLAGS_MASK                                    \
922     (MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_RESUMPTION             |      \
923      MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_EPHEMERAL_RESUMPTION   |      \
924      MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_EARLY_DATA)
925 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
926 
927 /**
928  * \brief          Callback type: server-side session cache getter
929  *
930  *                 The session cache is logically a key value store, with
931  *                 keys being session IDs and values being instances of
932  *                 mbedtls_ssl_session.
933  *
934  *                 This callback retrieves an entry in this key-value store.
935  *
936  * \param data            The address of the session cache structure to query.
937  * \param session_id      The buffer holding the session ID to query.
938  * \param session_id_len  The length of \p session_id in Bytes.
939  * \param session         The address of the session structure to populate.
940  *                        It is initialized with mbdtls_ssl_session_init(),
941  *                        and the callback must always leave it in a state
942  *                        where it can safely be freed via
943  *                        mbedtls_ssl_session_free() independent of the
944  *                        return code of this function.
945  *
946  * \return                \c 0 on success
947  * \return                A non-zero return value on failure.
948  *
949  */
950 typedef int mbedtls_ssl_cache_get_t(void *data,
951                                     unsigned char const *session_id,
952                                     size_t session_id_len,
953                                     mbedtls_ssl_session *session);
954 /**
955  * \brief          Callback type: server-side session cache setter
956  *
957  *                 The session cache is logically a key value store, with
958  *                 keys being session IDs and values being instances of
959  *                 mbedtls_ssl_session.
960  *
961  *                 This callback sets an entry in this key-value store.
962  *
963  * \param data            The address of the session cache structure to modify.
964  * \param session_id      The buffer holding the session ID to query.
965  * \param session_id_len  The length of \p session_id in Bytes.
966  * \param session         The address of the session to be stored in the
967  *                        session cache.
968  *
969  * \return                \c 0 on success
970  * \return                A non-zero return value on failure.
971  */
972 typedef int mbedtls_ssl_cache_set_t(void *data,
973                                     unsigned char const *session_id,
974                                     size_t session_id_len,
975                                     const mbedtls_ssl_session *session);
976 
977 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
978 #if defined(MBEDTLS_X509_CRT_PARSE_C)
979 /**
980  * \brief           Callback type: start external signature operation.
981  *
982  *                  This callback is called during an SSL handshake to start
983  *                  a signature decryption operation using an
984  *                  external processor. The parameter \p cert contains
985  *                  the public key; it is up to the callback function to
986  *                  determine how to access the associated private key.
987  *
988  *                  This function typically sends or enqueues a request, and
989  *                  does not wait for the operation to complete. This allows
990  *                  the handshake step to be non-blocking.
991  *
992  *                  The parameters \p ssl and \p cert are guaranteed to remain
993  *                  valid throughout the handshake. On the other hand, this
994  *                  function must save the contents of \p hash if the value
995  *                  is needed for later processing, because the \p hash buffer
996  *                  is no longer valid after this function returns.
997  *
998  *                  This function may call mbedtls_ssl_set_async_operation_data()
999  *                  to store an operation context for later retrieval
1000  *                  by the resume or cancel callback.
1001  *
1002  * \note            For RSA signatures, this function must produce output
1003  *                  that is consistent with PKCS#1 v1.5 in the same way as
1004  *                  mbedtls_rsa_pkcs1_sign(). Before the private key operation,
1005  *                  apply the padding steps described in RFC 8017, section 9.2
1006  *                  "EMSA-PKCS1-v1_5" as follows.
1007  *                  - If \p md_alg is #MBEDTLS_MD_NONE, apply the PKCS#1 v1.5
1008  *                    encoding, treating \p hash as the DigestInfo to be
1009  *                    padded. In other words, apply EMSA-PKCS1-v1_5 starting
1010  *                    from step 3, with `T = hash` and `tLen = hash_len`.
1011  *                  - If `md_alg != MBEDTLS_MD_NONE`, apply the PKCS#1 v1.5
1012  *                    encoding, treating \p hash as the hash to be encoded and
1013  *                    padded. In other words, apply EMSA-PKCS1-v1_5 starting
1014  *                    from step 2, with `digestAlgorithm` obtained by calling
1015  *                    mbedtls_oid_get_oid_by_md() on \p md_alg.
1016  *
1017  * \note            For ECDSA signatures, the output format is the DER encoding
1018  *                  `Ecdsa-Sig-Value` defined in
1019  *                  [RFC 4492 section 5.4](https://tools.ietf.org/html/rfc4492#section-5.4).
1020  *
1021  * \param ssl             The SSL connection instance. It should not be
1022  *                        modified other than via
1023  *                        mbedtls_ssl_set_async_operation_data().
1024  * \param cert            Certificate containing the public key.
1025  *                        In simple cases, this is one of the pointers passed to
1026  *                        mbedtls_ssl_conf_own_cert() when configuring the SSL
1027  *                        connection. However, if other callbacks are used, this
1028  *                        property may not hold. For example, if an SNI callback
1029  *                        is registered with mbedtls_ssl_conf_sni(), then
1030  *                        this callback determines what certificate is used.
1031  * \param md_alg          Hash algorithm.
1032  * \param hash            Buffer containing the hash. This buffer is
1033  *                        no longer valid when the function returns.
1034  * \param hash_len        Size of the \c hash buffer in bytes.
1035  *
1036  * \return          0 if the operation was started successfully and the SSL
1037  *                  stack should call the resume callback immediately.
1038  * \return          #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if the operation
1039  *                  was started successfully and the SSL stack should return
1040  *                  immediately without calling the resume callback yet.
1041  * \return          #MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH if the external
1042  *                  processor does not support this key. The SSL stack will
1043  *                  use the private key object instead.
1044  * \return          Any other error indicates a fatal failure and is
1045  *                  propagated up the call chain. The callback should
1046  *                  use \c MBEDTLS_ERR_PK_xxx error codes, and <b>must not</b>
1047  *                  use \c MBEDTLS_ERR_SSL_xxx error codes except as
1048  *                  directed in the documentation of this callback.
1049  */
1050 typedef int mbedtls_ssl_async_sign_t(mbedtls_ssl_context *ssl,
1051                                      mbedtls_x509_crt *cert,
1052                                      mbedtls_md_type_t md_alg,
1053                                      const unsigned char *hash,
1054                                      size_t hash_len);
1055 
1056 /**
1057  * \brief           Callback type: start external decryption operation.
1058  *
1059  *                  This callback is called during an SSL handshake to start
1060  *                  an RSA decryption operation using an
1061  *                  external processor. The parameter \p cert contains
1062  *                  the public key; it is up to the callback function to
1063  *                  determine how to access the associated private key.
1064  *
1065  *                  This function typically sends or enqueues a request, and
1066  *                  does not wait for the operation to complete. This allows
1067  *                  the handshake step to be non-blocking.
1068  *
1069  *                  The parameters \p ssl and \p cert are guaranteed to remain
1070  *                  valid throughout the handshake. On the other hand, this
1071  *                  function must save the contents of \p input if the value
1072  *                  is needed for later processing, because the \p input buffer
1073  *                  is no longer valid after this function returns.
1074  *
1075  *                  This function may call mbedtls_ssl_set_async_operation_data()
1076  *                  to store an operation context for later retrieval
1077  *                  by the resume or cancel callback.
1078  *
1079  * \warning         RSA decryption as used in TLS is subject to a potential
1080  *                  timing side channel attack first discovered by Bleichenbacher
1081  *                  in 1998. This attack can be remotely exploitable
1082  *                  in practice. To avoid this attack, you must ensure that
1083  *                  if the callback performs an RSA decryption, the time it
1084  *                  takes to execute and return the result does not depend
1085  *                  on whether the RSA decryption succeeded or reported
1086  *                  invalid padding.
1087  *
1088  * \param ssl             The SSL connection instance. It should not be
1089  *                        modified other than via
1090  *                        mbedtls_ssl_set_async_operation_data().
1091  * \param cert            Certificate containing the public key.
1092  *                        In simple cases, this is one of the pointers passed to
1093  *                        mbedtls_ssl_conf_own_cert() when configuring the SSL
1094  *                        connection. However, if other callbacks are used, this
1095  *                        property may not hold. For example, if an SNI callback
1096  *                        is registered with mbedtls_ssl_conf_sni(), then
1097  *                        this callback determines what certificate is used.
1098  * \param input           Buffer containing the input ciphertext. This buffer
1099  *                        is no longer valid when the function returns.
1100  * \param input_len       Size of the \p input buffer in bytes.
1101  *
1102  * \return          0 if the operation was started successfully and the SSL
1103  *                  stack should call the resume callback immediately.
1104  * \return          #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if the operation
1105  *                  was started successfully and the SSL stack should return
1106  *                  immediately without calling the resume callback yet.
1107  * \return          #MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH if the external
1108  *                  processor does not support this key. The SSL stack will
1109  *                  use the private key object instead.
1110  * \return          Any other error indicates a fatal failure and is
1111  *                  propagated up the call chain. The callback should
1112  *                  use \c MBEDTLS_ERR_PK_xxx error codes, and <b>must not</b>
1113  *                  use \c MBEDTLS_ERR_SSL_xxx error codes except as
1114  *                  directed in the documentation of this callback.
1115  */
1116 typedef int mbedtls_ssl_async_decrypt_t(mbedtls_ssl_context *ssl,
1117                                         mbedtls_x509_crt *cert,
1118                                         const unsigned char *input,
1119                                         size_t input_len);
1120 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1121 
1122 /**
1123  * \brief           Callback type: resume external operation.
1124  *
1125  *                  This callback is called during an SSL handshake to resume
1126  *                  an external operation started by the
1127  *                  ::mbedtls_ssl_async_sign_t or
1128  *                  ::mbedtls_ssl_async_decrypt_t callback.
1129  *
1130  *                  This function typically checks the status of a pending
1131  *                  request or causes the request queue to make progress, and
1132  *                  does not wait for the operation to complete. This allows
1133  *                  the handshake step to be non-blocking.
1134  *
1135  *                  This function may call mbedtls_ssl_get_async_operation_data()
1136  *                  to retrieve an operation context set by the start callback.
1137  *                  It may call mbedtls_ssl_set_async_operation_data() to modify
1138  *                  this context.
1139  *
1140  *                  Note that when this function returns a status other than
1141  *                  #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS, it must free any
1142  *                  resources associated with the operation.
1143  *
1144  * \param ssl             The SSL connection instance. It should not be
1145  *                        modified other than via
1146  *                        mbedtls_ssl_set_async_operation_data().
1147  * \param output          Buffer containing the output (signature or decrypted
1148  *                        data) on success.
1149  * \param output_len      On success, number of bytes written to \p output.
1150  * \param output_size     Size of the \p output buffer in bytes.
1151  *
1152  * \return          0 if output of the operation is available in the
1153  *                  \p output buffer.
1154  * \return          #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if the operation
1155  *                  is still in progress. Subsequent requests for progress
1156  *                  on the SSL connection will call the resume callback
1157  *                  again.
1158  * \return          Any other error means that the operation is aborted.
1159  *                  The SSL handshake is aborted. The callback should
1160  *                  use \c MBEDTLS_ERR_PK_xxx error codes, and <b>must not</b>
1161  *                  use \c MBEDTLS_ERR_SSL_xxx error codes except as
1162  *                  directed in the documentation of this callback.
1163  */
1164 typedef int mbedtls_ssl_async_resume_t(mbedtls_ssl_context *ssl,
1165                                        unsigned char *output,
1166                                        size_t *output_len,
1167                                        size_t output_size);
1168 
1169 /**
1170  * \brief           Callback type: cancel external operation.
1171  *
1172  *                  This callback is called if an SSL connection is closed
1173  *                  while an asynchronous operation is in progress. Note that
1174  *                  this callback is not called if the
1175  *                  ::mbedtls_ssl_async_resume_t callback has run and has
1176  *                  returned a value other than
1177  *                  #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS, since in that case
1178  *                  the asynchronous operation has already completed.
1179  *
1180  *                  This function may call mbedtls_ssl_get_async_operation_data()
1181  *                  to retrieve an operation context set by the start callback.
1182  *
1183  * \param ssl             The SSL connection instance. It should not be
1184  *                        modified.
1185  */
1186 typedef void mbedtls_ssl_async_cancel_t(mbedtls_ssl_context *ssl);
1187 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
1188 
1189 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) &&        \
1190     !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
1191 #define MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN  48
1192 #if defined(MBEDTLS_MD_CAN_SHA256)
1193 #define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA256
1194 #define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN  32
1195 #elif defined(MBEDTLS_MD_CAN_SHA384)
1196 #define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA384
1197 #define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN  48
1198 #elif defined(MBEDTLS_MD_CAN_SHA1)
1199 #define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA1
1200 #define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN  20
1201 #else
1202 /* This is already checked in check_config.h, but be sure. */
1203 #error "Bad configuration - need SHA-1, SHA-256 or SHA-512 enabled to compute digest of peer CRT."
1204 #endif
1205 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED &&
1206           !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
1207 
1208 typedef struct {
1209     unsigned char client_application_traffic_secret_N[MBEDTLS_TLS1_3_MD_MAX_SIZE];
1210     unsigned char server_application_traffic_secret_N[MBEDTLS_TLS1_3_MD_MAX_SIZE];
1211     unsigned char exporter_master_secret[MBEDTLS_TLS1_3_MD_MAX_SIZE];
1212     unsigned char resumption_master_secret[MBEDTLS_TLS1_3_MD_MAX_SIZE];
1213 } mbedtls_ssl_tls13_application_secrets;
1214 
1215 #if defined(MBEDTLS_SSL_DTLS_SRTP)
1216 
1217 #define MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH             255
1218 #define MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH    4
1219 /*
1220  * For code readability use a typedef for DTLS-SRTP profiles
1221  *
1222  * Use_srtp extension protection profiles values as defined in
1223  * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
1224  *
1225  * Reminder: if this list is expanded mbedtls_ssl_check_srtp_profile_value
1226  * must be updated too.
1227  */
1228 #define MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80     ((uint16_t) 0x0001)
1229 #define MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32     ((uint16_t) 0x0002)
1230 #define MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80          ((uint16_t) 0x0005)
1231 #define MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32          ((uint16_t) 0x0006)
1232 /* This one is not iana defined, but for code readability. */
1233 #define MBEDTLS_TLS_SRTP_UNSET                      ((uint16_t) 0x0000)
1234 
1235 typedef uint16_t mbedtls_ssl_srtp_profile;
1236 
1237 typedef struct mbedtls_dtls_srtp_info_t {
1238     /*! The SRTP profile that was negotiated. */
1239     mbedtls_ssl_srtp_profile MBEDTLS_PRIVATE(chosen_dtls_srtp_profile);
1240     /*! The length of mki_value. */
1241     uint16_t MBEDTLS_PRIVATE(mki_len);
1242     /*! The mki_value used, with max size of 256 bytes. */
1243     unsigned char MBEDTLS_PRIVATE(mki_value)[MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH];
1244 }
1245 mbedtls_dtls_srtp_info;
1246 
1247 #endif /* MBEDTLS_SSL_DTLS_SRTP */
1248 
1249 /** Human-friendly representation of the (D)TLS protocol version. */
1250 typedef enum {
1251     MBEDTLS_SSL_VERSION_UNKNOWN, /*!< Context not in use or version not yet negotiated. */
1252     MBEDTLS_SSL_VERSION_TLS1_2 = 0x0303, /*!< (D)TLS 1.2 */
1253     MBEDTLS_SSL_VERSION_TLS1_3 = 0x0304, /*!< (D)TLS 1.3 */
1254 } mbedtls_ssl_protocol_version;
1255 
1256 /*
1257  * This structure is used for storing current session data.
1258  *
1259  * Note: when changing this definition, we need to check and update:
1260  *  - in tests/suites/test_suite_ssl.function:
1261  *      ssl_populate_session() and ssl_serialize_session_save_load()
1262  *  - in library/ssl_tls.c:
1263  *      mbedtls_ssl_session_init() and mbedtls_ssl_session_free()
1264  *      mbedtls_ssl_session_save() and ssl_session_load()
1265  *      ssl_session_copy()
1266  */
1267 struct mbedtls_ssl_session {
1268 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
1269     unsigned char MBEDTLS_PRIVATE(mfl_code);     /*!< MaxFragmentLength negotiated by peer */
1270 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
1271 
1272 /*!< RecordSizeLimit received from the peer */
1273 #if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
1274     uint16_t MBEDTLS_PRIVATE(record_size_limit);
1275 #endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */
1276 
1277     unsigned char MBEDTLS_PRIVATE(exported);
1278     uint8_t MBEDTLS_PRIVATE(endpoint);          /*!< 0: client, 1: server */
1279 
1280     /** TLS version negotiated in the session. Used if and when renegotiating
1281      *  or resuming a session instead of the configured minor TLS version.
1282      */
1283     mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(tls_version);
1284 
1285 #if defined(MBEDTLS_HAVE_TIME)
1286     mbedtls_time_t MBEDTLS_PRIVATE(start);       /*!< start time of current session */
1287 #endif
1288     int MBEDTLS_PRIVATE(ciphersuite);            /*!< chosen ciphersuite */
1289     size_t MBEDTLS_PRIVATE(id_len);              /*!< session id length  */
1290     unsigned char MBEDTLS_PRIVATE(id)[32];       /*!< session identifier */
1291     unsigned char MBEDTLS_PRIVATE(master)[48];   /*!< the master secret  */
1292 
1293 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1294 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
1295     mbedtls_x509_crt *MBEDTLS_PRIVATE(peer_cert);       /*!< peer X.509 cert chain */
1296 #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
1297     /*! The digest of the peer's end-CRT. This must be kept to detect CRT
1298      *  changes during renegotiation, mitigating the triple handshake attack. */
1299     unsigned char *MBEDTLS_PRIVATE(peer_cert_digest);
1300     size_t MBEDTLS_PRIVATE(peer_cert_digest_len);
1301     mbedtls_md_type_t MBEDTLS_PRIVATE(peer_cert_digest_type);
1302 #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
1303 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1304     uint32_t MBEDTLS_PRIVATE(verify_result);          /*!<  verification result     */
1305 
1306 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
1307     unsigned char *MBEDTLS_PRIVATE(ticket);      /*!< RFC 5077 session ticket */
1308     size_t MBEDTLS_PRIVATE(ticket_len);          /*!< session ticket length   */
1309     uint32_t MBEDTLS_PRIVATE(ticket_lifetime);   /*!< ticket lifetime hint    */
1310 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
1311 
1312 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C) && \
1313     defined(MBEDTLS_HAVE_TIME)
1314     /*! When a ticket is created by a TLS server as part of an established TLS
1315      *  session, the ticket creation time may need to be saved for the ticket
1316      *  module to be able to check the ticket age when the ticket is used.
1317      *  That's the purpose of this field.
1318      *  Before creating a new ticket, an Mbed TLS server set this field with
1319      *  its current time in milliseconds. This time may then be saved in the
1320      *  session ticket data by the session ticket writing function and
1321      *  recovered by the ticket parsing function later when the ticket is used.
1322      *  The ticket module may then use this time to compute the ticket age and
1323      *  determine if it has expired or not.
1324      *  The Mbed TLS implementations of the session ticket writing and parsing
1325      *  functions save and retrieve the ticket creation time as part of the
1326      *  session ticket data. The session ticket parsing function relies on
1327      *  the mbedtls_ssl_session_get_ticket_creation_time() API to get the
1328      *  ticket creation time from the session ticket data.
1329      */
1330     mbedtls_ms_time_t MBEDTLS_PRIVATE(ticket_creation_time);
1331 #endif
1332 
1333 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
1334     uint32_t MBEDTLS_PRIVATE(ticket_age_add);     /*!< Randomly generated value used to obscure the age of the ticket */
1335     uint8_t MBEDTLS_PRIVATE(ticket_flags);        /*!< Ticket flags */
1336     uint8_t MBEDTLS_PRIVATE(resumption_key_len);  /*!< resumption_key length */
1337     unsigned char MBEDTLS_PRIVATE(resumption_key)[MBEDTLS_SSL_TLS1_3_TICKET_RESUMPTION_KEY_LEN];
1338 
1339 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) && defined(MBEDTLS_SSL_CLI_C)
1340     char *MBEDTLS_PRIVATE(hostname);             /*!< host name binded with tickets */
1341 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION && MBEDTLS_SSL_CLI_C */
1342 
1343 #if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_ALPN) && defined(MBEDTLS_SSL_SRV_C)
1344     char *ticket_alpn;                      /*!< ALPN negotiated in the session
1345                                                  during which the ticket was generated. */
1346 #endif
1347 
1348 #if defined(MBEDTLS_HAVE_TIME) && defined(MBEDTLS_SSL_CLI_C)
1349     /*! Time in milliseconds when the last ticket was received. */
1350     mbedtls_ms_time_t MBEDTLS_PRIVATE(ticket_reception_time);
1351 #endif
1352 #endif /*  MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
1353 
1354 #if defined(MBEDTLS_SSL_EARLY_DATA)
1355     uint32_t MBEDTLS_PRIVATE(max_early_data_size);          /*!< maximum amount of early data in tickets */
1356 #endif
1357 
1358 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
1359     int MBEDTLS_PRIVATE(encrypt_then_mac);       /*!< flag for EtM activation                */
1360 #endif
1361 
1362 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
1363     mbedtls_ssl_tls13_application_secrets MBEDTLS_PRIVATE(app_secrets);
1364 #endif
1365 };
1366 
1367 /*
1368  * Identifiers for PRFs used in various versions of TLS.
1369  */
1370 typedef enum {
1371     MBEDTLS_SSL_TLS_PRF_NONE,
1372     MBEDTLS_SSL_TLS_PRF_SHA384,
1373     MBEDTLS_SSL_TLS_PRF_SHA256,
1374     MBEDTLS_SSL_HKDF_EXPAND_SHA384,
1375     MBEDTLS_SSL_HKDF_EXPAND_SHA256
1376 }
1377 mbedtls_tls_prf_types;
1378 
1379 typedef enum {
1380     MBEDTLS_SSL_KEY_EXPORT_TLS12_MASTER_SECRET = 0,
1381 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
1382     MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_EARLY_SECRET,
1383     MBEDTLS_SSL_KEY_EXPORT_TLS1_3_EARLY_EXPORTER_SECRET,
1384     MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_HANDSHAKE_TRAFFIC_SECRET,
1385     MBEDTLS_SSL_KEY_EXPORT_TLS1_3_SERVER_HANDSHAKE_TRAFFIC_SECRET,
1386     MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_APPLICATION_TRAFFIC_SECRET,
1387     MBEDTLS_SSL_KEY_EXPORT_TLS1_3_SERVER_APPLICATION_TRAFFIC_SECRET,
1388 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
1389 } mbedtls_ssl_key_export_type;
1390 
1391 /**
1392  * \brief           Callback type: Export key alongside random values for
1393  *                                 session identification, and PRF for
1394  *                                 implementation of TLS key exporters.
1395  *
1396  * \param p_expkey   Context for the callback.
1397  * \param type       The type of the key that is being exported.
1398  * \param secret     The address of the buffer holding the secret
1399  *                   that's being exporterd.
1400  * \param secret_len The length of \p secret in bytes.
1401  * \param client_random The client random bytes.
1402  * \param server_random The server random bytes.
1403  * \param tls_prf_type The identifier for the PRF used in the handshake
1404  *                     to which the key belongs.
1405  */
1406 typedef void mbedtls_ssl_export_keys_t(void *p_expkey,
1407                                        mbedtls_ssl_key_export_type type,
1408                                        const unsigned char *secret,
1409                                        size_t secret_len,
1410                                        const unsigned char client_random[32],
1411                                        const unsigned char server_random[32],
1412                                        mbedtls_tls_prf_types tls_prf_type);
1413 
1414 #if defined(MBEDTLS_SSL_SRV_C)
1415 /**
1416  * \brief           Callback type: generic handshake callback
1417  *
1418  * \note            Callbacks may use user_data funcs to set/get app user data.
1419  *                  See \c mbedtls_ssl_get_user_data_p()
1420  *                      \c mbedtls_ssl_get_user_data_n()
1421  *                      \c mbedtls_ssl_conf_get_user_data_p()
1422  *                      \c mbedtls_ssl_conf_get_user_data_n()
1423  *
1424  * \param ssl       \c mbedtls_ssl_context on which the callback is run
1425  *
1426  * \return          The return value of the callback is 0 if successful,
1427  *                  or a specific MBEDTLS_ERR_XXX code, which will cause
1428  *                  the handshake to be aborted.
1429  */
1430 typedef int (*mbedtls_ssl_hs_cb_t)(mbedtls_ssl_context *ssl);
1431 #endif
1432 
1433 /* A type for storing user data in a library structure.
1434  *
1435  * The representation of type may change in future versions of the library.
1436  * Only the behaviors guaranteed by documented accessor functions are
1437  * guaranteed to remain stable.
1438  */
1439 typedef union {
1440     uintptr_t n;                /* typically a handle to an associated object */
1441     void *p;                    /* typically a pointer to extra data */
1442 } mbedtls_ssl_user_data_t;
1443 
1444 /**
1445  * SSL/TLS configuration to be shared between mbedtls_ssl_context structures.
1446  */
1447 struct mbedtls_ssl_config {
1448     /* Group items mostly by size. This helps to reduce memory wasted to
1449      * padding. It also helps to keep smaller fields early in the structure,
1450      * so that elements tend to be in the 128-element direct access window
1451      * on Arm Thumb, which reduces the code size. */
1452 
1453     mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(max_tls_version);  /*!< max. TLS version used */
1454     mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(min_tls_version);  /*!< min. TLS version used */
1455 
1456     /*
1457      * Flags (could be bit-fields to save RAM, but separate bytes make
1458      * the code smaller on architectures with an instruction for direct
1459      * byte access).
1460      */
1461 
1462     uint8_t MBEDTLS_PRIVATE(endpoint);      /*!< 0: client, 1: server               */
1463     uint8_t MBEDTLS_PRIVATE(transport);     /*!< 0: stream (TLS), 1: datagram (DTLS)    */
1464     uint8_t MBEDTLS_PRIVATE(authmode);      /*!< MBEDTLS_SSL_VERIFY_XXX             */
1465     /* needed even with renego disabled for LEGACY_BREAK_HANDSHAKE          */
1466     uint8_t MBEDTLS_PRIVATE(allow_legacy_renegotiation); /*!< MBEDTLS_LEGACY_XXX   */
1467 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
1468     uint8_t MBEDTLS_PRIVATE(mfl_code);      /*!< desired fragment length indicator
1469                                                  (MBEDTLS_SSL_MAX_FRAG_LEN_XXX) */
1470 #endif
1471 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
1472     uint8_t MBEDTLS_PRIVATE(encrypt_then_mac); /*!< negotiate encrypt-then-mac?    */
1473 #endif
1474 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
1475     uint8_t MBEDTLS_PRIVATE(extended_ms);   /*!< negotiate extended master secret?  */
1476 #endif
1477 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1478     uint8_t MBEDTLS_PRIVATE(anti_replay);   /*!< detect and prevent replay?         */
1479 #endif
1480 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1481     uint8_t MBEDTLS_PRIVATE(disable_renegotiation); /*!< disable renegotiation?     */
1482 #endif
1483 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
1484     defined(MBEDTLS_SSL_CLI_C)
1485     uint8_t MBEDTLS_PRIVATE(session_tickets);   /*!< use session tickets? */
1486 #endif
1487 
1488 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
1489     defined(MBEDTLS_SSL_SRV_C) && \
1490     defined(MBEDTLS_SSL_PROTO_TLS1_3)
1491     uint16_t MBEDTLS_PRIVATE(new_session_tickets_count);   /*!< number of NewSessionTicket */
1492 #endif
1493 
1494 #if defined(MBEDTLS_SSL_SRV_C)
1495     uint8_t MBEDTLS_PRIVATE(cert_req_ca_list);  /*!< enable sending CA list in
1496                                                      Certificate Request messages? */
1497     uint8_t MBEDTLS_PRIVATE(respect_cli_pref);  /*!< pick the ciphersuite according to
1498                                                      the client's preferences rather
1499                                                      than ours? */
1500 #endif
1501 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
1502     uint8_t MBEDTLS_PRIVATE(ignore_unexpected_cid); /*!< Should DTLS record with
1503                                                      *   unexpected CID
1504                                                      *   lead to failure? */
1505 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1506 #if defined(MBEDTLS_SSL_DTLS_SRTP)
1507     uint8_t MBEDTLS_PRIVATE(dtls_srtp_mki_support); /* support having mki_value
1508                                                        in the use_srtp extension? */
1509 #endif
1510 
1511     /*
1512      * Pointers
1513      */
1514 
1515     /** Allowed ciphersuites for (D)TLS 1.2 (0-terminated)                  */
1516     const int *MBEDTLS_PRIVATE(ciphersuite_list);
1517 
1518 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
1519     /** Allowed TLS 1.3 key exchange modes.                                 */
1520     int MBEDTLS_PRIVATE(tls13_kex_modes);
1521 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
1522 
1523     /** Callback for printing debug output                                  */
1524     void(*MBEDTLS_PRIVATE(f_dbg))(void *, int, const char *, int, const char *);
1525     void *MBEDTLS_PRIVATE(p_dbg);                    /*!< context for the debug function     */
1526 
1527     /** Callback for getting (pseudo-)random numbers                        */
1528     int(*MBEDTLS_PRIVATE(f_rng))(void *, unsigned char *, size_t);
1529     void *MBEDTLS_PRIVATE(p_rng);                    /*!< context for the RNG function       */
1530 
1531     /** Callback to retrieve a session from the cache                       */
1532     mbedtls_ssl_cache_get_t *MBEDTLS_PRIVATE(f_get_cache);
1533     /** Callback to store a session into the cache                          */
1534     mbedtls_ssl_cache_set_t *MBEDTLS_PRIVATE(f_set_cache);
1535     void *MBEDTLS_PRIVATE(p_cache);                  /*!< context for cache callbacks        */
1536 
1537 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
1538     /** Callback for setting cert according to SNI extension                */
1539     int(*MBEDTLS_PRIVATE(f_sni))(void *, mbedtls_ssl_context *, const unsigned char *, size_t);
1540     void *MBEDTLS_PRIVATE(p_sni);                    /*!< context for SNI callback           */
1541 #endif
1542 
1543 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1544     /** Callback to customize X.509 certificate chain verification          */
1545     int(*MBEDTLS_PRIVATE(f_vrfy))(void *, mbedtls_x509_crt *, int, uint32_t *);
1546     void *MBEDTLS_PRIVATE(p_vrfy);                   /*!< context for X.509 verify calllback */
1547 #endif
1548 
1549 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED)
1550 #if defined(MBEDTLS_SSL_SRV_C)
1551     /** Callback to retrieve PSK key from identity                          */
1552     int(*MBEDTLS_PRIVATE(f_psk))(void *, mbedtls_ssl_context *, const unsigned char *, size_t);
1553     void *MBEDTLS_PRIVATE(p_psk);                    /*!< context for PSK callback           */
1554 #endif
1555 #endif
1556 
1557 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
1558     /** Callback to create & write a cookie for ClientHello verification    */
1559     int(*MBEDTLS_PRIVATE(f_cookie_write))(void *, unsigned char **, unsigned char *,
1560                                           const unsigned char *, size_t);
1561     /** Callback to verify validity of a ClientHello cookie                 */
1562     int(*MBEDTLS_PRIVATE(f_cookie_check))(void *, const unsigned char *, size_t,
1563                                           const unsigned char *, size_t);
1564     void *MBEDTLS_PRIVATE(p_cookie);                 /*!< context for the cookie callbacks   */
1565 #endif
1566 
1567 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C)
1568     /** Callback to create & write a session ticket                         */
1569     int(*MBEDTLS_PRIVATE(f_ticket_write))(void *, const mbedtls_ssl_session *,
1570                                           unsigned char *, const unsigned char *, size_t *,
1571                                           uint32_t *);
1572     /** Callback to parse a session ticket into a session structure         */
1573     int(*MBEDTLS_PRIVATE(f_ticket_parse))(void *, mbedtls_ssl_session *, unsigned char *, size_t);
1574     void *MBEDTLS_PRIVATE(p_ticket);                 /*!< context for the ticket callbacks   */
1575 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
1576 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
1577     size_t MBEDTLS_PRIVATE(cid_len); /*!< The length of CIDs for incoming DTLS records.      */
1578 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1579 
1580 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1581     const mbedtls_x509_crt_profile *MBEDTLS_PRIVATE(cert_profile); /*!< verification profile */
1582     mbedtls_ssl_key_cert *MBEDTLS_PRIVATE(key_cert); /*!< own certificate/key pair(s)        */
1583     mbedtls_x509_crt *MBEDTLS_PRIVATE(ca_chain);     /*!< trusted CAs                        */
1584     mbedtls_x509_crl *MBEDTLS_PRIVATE(ca_crl);       /*!< trusted CAs CRLs                   */
1585 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
1586     mbedtls_x509_crt_ca_cb_t MBEDTLS_PRIVATE(f_ca_cb);
1587     void *MBEDTLS_PRIVATE(p_ca_cb);
1588 #endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
1589 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1590 
1591 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
1592 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1593     mbedtls_ssl_async_sign_t *MBEDTLS_PRIVATE(f_async_sign_start); /*!< start asynchronous signature operation */
1594     mbedtls_ssl_async_decrypt_t *MBEDTLS_PRIVATE(f_async_decrypt_start); /*!< start asynchronous decryption operation */
1595 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1596     mbedtls_ssl_async_resume_t *MBEDTLS_PRIVATE(f_async_resume); /*!< resume asynchronous operation */
1597     mbedtls_ssl_async_cancel_t *MBEDTLS_PRIVATE(f_async_cancel); /*!< cancel asynchronous operation */
1598     void *MBEDTLS_PRIVATE(p_async_config_data); /*!< Configuration data set by mbedtls_ssl_conf_async_private_cb(). */
1599 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
1600 
1601 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
1602 
1603 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
1604     const int *MBEDTLS_PRIVATE(sig_hashes);         /*!< allowed signature hashes           */
1605 #endif
1606     const uint16_t *MBEDTLS_PRIVATE(sig_algs);      /*!< allowed signature algorithms       */
1607 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
1608 
1609 #if defined(MBEDTLS_ECP_C) && !defined(MBEDTLS_DEPRECATED_REMOVED)
1610     const mbedtls_ecp_group_id *MBEDTLS_PRIVATE(curve_list); /*!< allowed curves             */
1611 #endif
1612 
1613     const uint16_t *MBEDTLS_PRIVATE(group_list);     /*!< allowed IANA NamedGroups */
1614 
1615 #if defined(MBEDTLS_DHM_C)
1616     mbedtls_mpi MBEDTLS_PRIVATE(dhm_P);              /*!< prime modulus for DHM              */
1617     mbedtls_mpi MBEDTLS_PRIVATE(dhm_G);              /*!< generator for DHM                  */
1618 #endif
1619 
1620 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED)
1621 
1622 #if defined(MBEDTLS_USE_PSA_CRYPTO)
1623     mbedtls_svc_key_id_t MBEDTLS_PRIVATE(psk_opaque); /*!< PSA key slot holding opaque PSK. This field
1624                                                        *   should only be set via
1625                                                        *   mbedtls_ssl_conf_psk_opaque().
1626                                                        *   If either no PSK or a raw PSK have been
1627                                                        *   configured, this has value \c 0.
1628                                                        */
1629 #endif /* MBEDTLS_USE_PSA_CRYPTO */
1630     unsigned char *MBEDTLS_PRIVATE(psk);      /*!< The raw pre-shared key. This field should
1631                                                *   only be set via mbedtls_ssl_conf_psk().
1632                                                *   If either no PSK or an opaque PSK
1633                                                *   have been configured, this has value NULL. */
1634     size_t         MBEDTLS_PRIVATE(psk_len);  /*!< The length of the raw pre-shared key.
1635                                                *   This field should only be set via
1636                                                *   mbedtls_ssl_conf_psk().
1637                                                *   Its value is non-zero if and only if
1638                                                *   \c psk is not \c NULL. */
1639 
1640     unsigned char *MBEDTLS_PRIVATE(psk_identity);    /*!< The PSK identity for PSK negotiation.
1641                                                       *   This field should only be set via
1642                                                       *   mbedtls_ssl_conf_psk().
1643                                                       *   This is set if and only if either
1644                                                       *   \c psk or \c psk_opaque are set. */
1645     size_t         MBEDTLS_PRIVATE(psk_identity_len);/*!< The length of PSK identity.
1646                                                       *   This field should only be set via
1647                                                       *   mbedtls_ssl_conf_psk().
1648                                                       *   Its value is non-zero if and only if
1649                                                       *   \c psk is not \c NULL or \c psk_opaque
1650                                                       *   is not \c 0. */
1651 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED */
1652 
1653 #if defined(MBEDTLS_SSL_EARLY_DATA)
1654     int MBEDTLS_PRIVATE(early_data_enabled);     /*!< Early data enablement:
1655                                                   *   - MBEDTLS_SSL_EARLY_DATA_DISABLED,
1656                                                   *   - MBEDTLS_SSL_EARLY_DATA_ENABLED */
1657 
1658 #if defined(MBEDTLS_SSL_SRV_C)
1659     /* The maximum amount of 0-RTT data. RFC 8446 section 4.6.1 */
1660     uint32_t MBEDTLS_PRIVATE(max_early_data_size);
1661 #endif /* MBEDTLS_SSL_SRV_C */
1662 
1663 #endif /* MBEDTLS_SSL_EARLY_DATA */
1664 
1665 #if defined(MBEDTLS_SSL_ALPN)
1666     const char **MBEDTLS_PRIVATE(alpn_list);         /*!< ordered list of protocols          */
1667 #endif
1668 
1669 #if defined(MBEDTLS_SSL_DTLS_SRTP)
1670     /*! ordered list of supported srtp profile */
1671     const mbedtls_ssl_srtp_profile *MBEDTLS_PRIVATE(dtls_srtp_profile_list);
1672     /*! number of supported profiles */
1673     size_t MBEDTLS_PRIVATE(dtls_srtp_profile_list_len);
1674 #endif /* MBEDTLS_SSL_DTLS_SRTP */
1675 
1676     /*
1677      * Numerical settings (int)
1678      */
1679 
1680     uint32_t MBEDTLS_PRIVATE(read_timeout);          /*!< timeout for mbedtls_ssl_read (ms)  */
1681 
1682 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1683     uint32_t MBEDTLS_PRIVATE(hs_timeout_min);        /*!< initial value of the handshake
1684                                                         retransmission timeout (ms)        */
1685     uint32_t MBEDTLS_PRIVATE(hs_timeout_max);        /*!< maximum value of the handshake
1686                                                         retransmission timeout (ms)        */
1687 #endif
1688 
1689 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1690     int MBEDTLS_PRIVATE(renego_max_records);         /*!< grace period for renegotiation     */
1691     unsigned char MBEDTLS_PRIVATE(renego_period)[8]; /*!< value of the record counters
1692                                                         that triggers renegotiation        */
1693 #endif
1694 
1695     unsigned int MBEDTLS_PRIVATE(badmac_limit);      /*!< limit of records with a bad MAC    */
1696 
1697 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
1698     unsigned int MBEDTLS_PRIVATE(dhm_min_bitlen);    /*!< min. bit length of the DHM prime   */
1699 #endif
1700 
1701     /** User data pointer or handle.
1702      *
1703      * The library sets this to \p 0 when creating a context and does not
1704      * access it afterwards.
1705      */
1706     mbedtls_ssl_user_data_t MBEDTLS_PRIVATE(user_data);
1707 
1708 #if defined(MBEDTLS_SSL_SRV_C)
1709     mbedtls_ssl_hs_cb_t MBEDTLS_PRIVATE(f_cert_cb);  /*!< certificate selection callback */
1710 #endif /* MBEDTLS_SSL_SRV_C */
1711 
1712 #if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
1713     const mbedtls_x509_crt *MBEDTLS_PRIVATE(dn_hints);/*!< acceptable client cert issuers    */
1714 #endif
1715 };
1716 
1717 struct mbedtls_ssl_context {
1718     const mbedtls_ssl_config *MBEDTLS_PRIVATE(conf); /*!< configuration information          */
1719 
1720     /*
1721      * Miscellaneous
1722      */
1723     int MBEDTLS_PRIVATE(state);                  /*!< SSL handshake: current state     */
1724 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1725     int MBEDTLS_PRIVATE(renego_status);          /*!< Initial, in progress, pending?   */
1726     int MBEDTLS_PRIVATE(renego_records_seen);    /*!< Records since renego request, or with DTLS,
1727                                                     number of retransmissions of request if
1728                                                     renego_max_records is < 0           */
1729 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1730 
1731     /**
1732      * Maximum TLS version to be negotiated, then negotiated TLS version.
1733      *
1734      * It is initialized as the configured maximum TLS version to be
1735      * negotiated by mbedtls_ssl_setup().
1736      *
1737      * When renegotiating or resuming a session, it is overwritten in the
1738      * ClientHello writing preparation stage with the previously negotiated
1739      * TLS version.
1740      *
1741      * On client side, it is updated to the TLS version selected by the server
1742      * for the handshake when the ServerHello is received.
1743      *
1744      * On server side, it is updated to the TLS version the server selects for
1745      * the handshake when the ClientHello is received.
1746      */
1747     mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(tls_version);
1748 
1749 #if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_CLI_C)
1750     /**
1751      * State of the negotiation and transfer of early data. Reset to
1752      * MBEDTLS_SSL_EARLY_DATA_STATE_IDLE when the context is reset.
1753      */
1754     int MBEDTLS_PRIVATE(early_data_state);
1755 #endif
1756 
1757     unsigned MBEDTLS_PRIVATE(badmac_seen);       /*!< records with a bad MAC received    */
1758 
1759 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1760     /** Callback to customize X.509 certificate chain verification          */
1761     int(*MBEDTLS_PRIVATE(f_vrfy))(void *, mbedtls_x509_crt *, int, uint32_t *);
1762     void *MBEDTLS_PRIVATE(p_vrfy);                   /*!< context for X.509 verify callback */
1763 #endif
1764 
1765     mbedtls_ssl_send_t *MBEDTLS_PRIVATE(f_send); /*!< Callback for network send */
1766     mbedtls_ssl_recv_t *MBEDTLS_PRIVATE(f_recv); /*!< Callback for network receive */
1767     mbedtls_ssl_recv_timeout_t *MBEDTLS_PRIVATE(f_recv_timeout);
1768     /*!< Callback for network receive with timeout */
1769 
1770     void *MBEDTLS_PRIVATE(p_bio);                /*!< context for I/O operations   */
1771 
1772     /*
1773      * Session layer
1774      */
1775     mbedtls_ssl_session *MBEDTLS_PRIVATE(session_in);            /*!<  current session data (in)   */
1776     mbedtls_ssl_session *MBEDTLS_PRIVATE(session_out);           /*!<  current session data (out)  */
1777     mbedtls_ssl_session *MBEDTLS_PRIVATE(session);               /*!<  negotiated session data     */
1778     mbedtls_ssl_session *MBEDTLS_PRIVATE(session_negotiate);     /*!<  session data in negotiation */
1779 
1780     mbedtls_ssl_handshake_params *MBEDTLS_PRIVATE(handshake);    /*!<  params required only during
1781                                                                     the handshake process        */
1782 
1783     /*
1784      * Record layer transformations
1785      */
1786     mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_in);        /*!<  current transform params (in)
1787                                                                   *    This is always a reference,
1788                                                                   *    never an owning pointer.        */
1789     mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_out);       /*!<  current transform params (out)
1790                                                                   *    This is always a reference,
1791                                                                   *    never an owning pointer.        */
1792     mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform);           /*!<  negotiated transform params
1793                                                                   *    This pointer owns the transform
1794                                                                   *    it references.                  */
1795 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
1796     mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_negotiate); /*!<  transform params in negotiation
1797                                                                   *    This pointer owns the transform
1798                                                                   *    it references.                  */
1799 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
1800 
1801 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
1802     /*! The application data transform in TLS 1.3.
1803      *  This pointer owns the transform it references. */
1804     mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_application);
1805 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
1806 
1807     /*
1808      * Timers
1809      */
1810     void *MBEDTLS_PRIVATE(p_timer);              /*!< context for the timer callbacks */
1811 
1812     mbedtls_ssl_set_timer_t *MBEDTLS_PRIVATE(f_set_timer);       /*!< set timer callback */
1813     mbedtls_ssl_get_timer_t *MBEDTLS_PRIVATE(f_get_timer);       /*!< get timer callback */
1814 
1815     /*
1816      * Record layer (incoming data)
1817      */
1818     unsigned char *MBEDTLS_PRIVATE(in_buf);      /*!< input buffer                     */
1819     unsigned char *MBEDTLS_PRIVATE(in_ctr);      /*!< 64-bit incoming message counter
1820                                                     TLS: maintained by us
1821                                                     DTLS: read from peer             */
1822     unsigned char *MBEDTLS_PRIVATE(in_hdr);      /*!< start of record header           */
1823 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
1824     unsigned char *MBEDTLS_PRIVATE(in_cid);      /*!< The start of the CID;
1825                                                   *   (the end is marked by in_len).   */
1826 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1827     unsigned char *MBEDTLS_PRIVATE(in_len);      /*!< two-bytes message length field   */
1828     unsigned char *MBEDTLS_PRIVATE(in_iv);       /*!< ivlen-byte IV                    */
1829     unsigned char *MBEDTLS_PRIVATE(in_msg);      /*!< message contents (in_iv+ivlen)   */
1830     unsigned char *MBEDTLS_PRIVATE(in_offt);     /*!< read offset in application data  */
1831 
1832     int MBEDTLS_PRIVATE(in_msgtype);             /*!< record header: message type      */
1833     size_t MBEDTLS_PRIVATE(in_msglen);           /*!< record header: message length    */
1834     size_t MBEDTLS_PRIVATE(in_left);             /*!< amount of data read so far       */
1835 #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
1836     size_t MBEDTLS_PRIVATE(in_buf_len);          /*!< length of input buffer           */
1837 #endif
1838 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1839     uint16_t MBEDTLS_PRIVATE(in_epoch);          /*!< DTLS epoch for incoming records  */
1840     size_t MBEDTLS_PRIVATE(next_record_offset);  /*!< offset of the next record in datagram
1841                                                     (equal to in_left if none)       */
1842 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1843 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1844     uint64_t MBEDTLS_PRIVATE(in_window_top);     /*!< last validated record seq_num    */
1845     uint64_t MBEDTLS_PRIVATE(in_window);         /*!< bitmask for replay detection     */
1846 #endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */
1847 
1848     size_t MBEDTLS_PRIVATE(in_hslen);            /*!< current handshake message length,
1849                                                     including the handshake header   */
1850     int MBEDTLS_PRIVATE(nb_zero);                /*!< # of 0-length encrypted messages */
1851 
1852     int MBEDTLS_PRIVATE(keep_current_message);   /*!< drop or reuse current message
1853                                                     on next call to record layer? */
1854 
1855     /* The following three variables indicate if and, if yes,
1856      * what kind of alert is pending to be sent.
1857      */
1858     unsigned char MBEDTLS_PRIVATE(send_alert);   /*!< Determines if a fatal alert
1859                                                     should be sent. Values:
1860                                                     - \c 0 , no alert is to be sent.
1861                                                     - \c 1 , alert is to be sent. */
1862     unsigned char MBEDTLS_PRIVATE(alert_type);   /*!< Type of alert if send_alert
1863                                                     != 0 */
1864     int MBEDTLS_PRIVATE(alert_reason);           /*!< The error code to be returned
1865                                                     to the user once the fatal alert
1866                                                     has been sent. */
1867 
1868 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1869     uint8_t MBEDTLS_PRIVATE(disable_datagram_packing);  /*!< Disable packing multiple records
1870                                                          *   within a single datagram.  */
1871 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1872 
1873 #if defined(MBEDTLS_SSL_EARLY_DATA)
1874 #if defined(MBEDTLS_SSL_SRV_C)
1875     /*
1876      * One of:
1877      * MBEDTLS_SSL_EARLY_DATA_NO_DISCARD
1878      * MBEDTLS_SSL_EARLY_DATA_TRY_TO_DEPROTECT_AND_DISCARD
1879      * MBEDTLS_SSL_EARLY_DATA_DISCARD
1880      */
1881     uint8_t MBEDTLS_PRIVATE(discard_early_data_record);
1882 #endif
1883     uint32_t MBEDTLS_PRIVATE(total_early_data_size); /*!< Number of received/written early data bytes */
1884 #endif /* MBEDTLS_SSL_EARLY_DATA */
1885 
1886     /*
1887      * Record layer (outgoing data)
1888      */
1889     unsigned char *MBEDTLS_PRIVATE(out_buf);     /*!< output buffer                    */
1890     unsigned char *MBEDTLS_PRIVATE(out_ctr);     /*!< 64-bit outgoing message counter  */
1891     unsigned char *MBEDTLS_PRIVATE(out_hdr);     /*!< start of record header           */
1892 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
1893     unsigned char *MBEDTLS_PRIVATE(out_cid);     /*!< The start of the CID;
1894                                                   *   (the end is marked by in_len).   */
1895 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1896     unsigned char *MBEDTLS_PRIVATE(out_len);     /*!< two-bytes message length field   */
1897     unsigned char *MBEDTLS_PRIVATE(out_iv);      /*!< ivlen-byte IV                    */
1898     unsigned char *MBEDTLS_PRIVATE(out_msg);     /*!< message contents (out_iv+ivlen)  */
1899 
1900     int MBEDTLS_PRIVATE(out_msgtype);            /*!< record header: message type      */
1901     size_t MBEDTLS_PRIVATE(out_msglen);          /*!< record header: message length    */
1902     size_t MBEDTLS_PRIVATE(out_left);            /*!< amount of data not yet written   */
1903 #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
1904     size_t MBEDTLS_PRIVATE(out_buf_len);         /*!< length of output buffer          */
1905 #endif
1906 
1907     unsigned char MBEDTLS_PRIVATE(cur_out_ctr)[MBEDTLS_SSL_SEQUENCE_NUMBER_LEN]; /*!<  Outgoing record sequence  number. */
1908 
1909 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1910     uint16_t MBEDTLS_PRIVATE(mtu);               /*!< path mtu, used to fragment outgoing messages */
1911 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1912 
1913     /*
1914      * User settings
1915      */
1916 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1917     /** Expected peer CN for verification.
1918      *
1919      * Also used on clients for SNI,
1920      * and for TLS 1.3 session resumption using tickets.
1921      *
1922      * The value of this field can be:
1923      * - \p NULL in a newly initialized or reset context.
1924      * - A heap-allocated copy of the last value passed to
1925      *   mbedtls_ssl_set_hostname(), if the last call had a non-null
1926      *  \p hostname argument.
1927      * - A special value to indicate that mbedtls_ssl_set_hostname()
1928      *   was called with \p NULL (as opposed to never having been called).
1929      *   See `mbedtls_ssl_get_hostname_pointer()` in `ssl_tls.c`.
1930      *
1931      * If this field contains the value \p NULL and the configuration option
1932      * #MBEDTLS_SSL_CLI_ALLOW_WEAK_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME
1933      * is unset, on a TLS client, attempting to verify a server certificate
1934      * results in the error
1935      * #MBEDTLS_ERR_SSL_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME.
1936      *
1937      * If this field contains the special value described above, or if
1938      * the value is \p NULL and the configuration option
1939      * #MBEDTLS_SSL_CLI_ALLOW_WEAK_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME
1940      * is set, then the peer name verification is skipped, which may be
1941      * insecure, especially on a client. Furthermore, on a client, the
1942      * server_name extension is not sent, and the server name is ignored
1943      * in TLS 1.3 session resumption using tickets.
1944      */
1945     char *MBEDTLS_PRIVATE(hostname);
1946 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1947 
1948 #if defined(MBEDTLS_SSL_ALPN)
1949     const char *MBEDTLS_PRIVATE(alpn_chosen);    /*!<  negotiated protocol                   */
1950 #endif /* MBEDTLS_SSL_ALPN */
1951 
1952 #if defined(MBEDTLS_SSL_DTLS_SRTP)
1953     /*
1954      * use_srtp extension
1955      */
1956     mbedtls_dtls_srtp_info MBEDTLS_PRIVATE(dtls_srtp_info);
1957 #endif /* MBEDTLS_SSL_DTLS_SRTP */
1958 
1959     /*
1960      * Information for DTLS hello verify
1961      */
1962 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
1963     unsigned char  *MBEDTLS_PRIVATE(cli_id);         /*!<  transport-level ID of the client  */
1964     size_t          MBEDTLS_PRIVATE(cli_id_len);     /*!<  length of cli_id                  */
1965 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
1966 
1967     /*
1968      * Secure renegotiation
1969      */
1970     /* needed to know when to send extension on server */
1971     int MBEDTLS_PRIVATE(secure_renegotiation);           /*!<  does peer support legacy or
1972                                                             secure renegotiation           */
1973 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1974     size_t MBEDTLS_PRIVATE(verify_data_len);             /*!<  length of verify data stored   */
1975     char MBEDTLS_PRIVATE(own_verify_data)[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!<  previous handshake verify data */
1976     char MBEDTLS_PRIVATE(peer_verify_data)[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!<  previous handshake verify data */
1977 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1978 
1979 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
1980     /* CID configuration to use in subsequent handshakes. */
1981 
1982     /*! The next incoming CID, chosen by the user and applying to
1983      *  all subsequent handshakes. This may be different from the
1984      *  CID currently used in case the user has re-configured the CID
1985      *  after an initial handshake. */
1986     unsigned char MBEDTLS_PRIVATE(own_cid)[MBEDTLS_SSL_CID_IN_LEN_MAX];
1987     uint8_t MBEDTLS_PRIVATE(own_cid_len);   /*!< The length of \c own_cid. */
1988     uint8_t MBEDTLS_PRIVATE(negotiate_cid); /*!< This indicates whether the CID extension should
1989                                              *   be negotiated in the next handshake or not.
1990                                              *   Possible values are #MBEDTLS_SSL_CID_ENABLED
1991                                              *   and #MBEDTLS_SSL_CID_DISABLED. */
1992 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1993 
1994     /** Callback to export key block and master secret                      */
1995     mbedtls_ssl_export_keys_t *MBEDTLS_PRIVATE(f_export_keys);
1996     void *MBEDTLS_PRIVATE(p_export_keys);            /*!< context for key export callback    */
1997 
1998     /** User data pointer or handle.
1999      *
2000      * The library sets this to \p 0 when creating a context and does not
2001      * access it afterwards.
2002      *
2003      * \warning Serializing and restoring an SSL context with
2004      *          mbedtls_ssl_context_save() and mbedtls_ssl_context_load()
2005      *          does not currently restore the user data.
2006      */
2007     mbedtls_ssl_user_data_t MBEDTLS_PRIVATE(user_data);
2008 };
2009 
2010 /**
2011  * \brief               Return the name of the ciphersuite associated with the
2012  *                      given ID
2013  *
2014  * \param ciphersuite_id SSL ciphersuite ID
2015  *
2016  * \return              a string containing the ciphersuite name
2017  */
2018 const char *mbedtls_ssl_get_ciphersuite_name(const int ciphersuite_id);
2019 
2020 /**
2021  * \brief               Return the ID of the ciphersuite associated with the
2022  *                      given name
2023  *
2024  * \param ciphersuite_name SSL ciphersuite name
2025  *
2026  * \return              the ID with the ciphersuite or 0 if not found
2027  */
2028 int mbedtls_ssl_get_ciphersuite_id(const char *ciphersuite_name);
2029 
2030 /**
2031  * \brief          Initialize an SSL context
2032  *                 Just makes the context ready for mbedtls_ssl_setup() or
2033  *                 mbedtls_ssl_free()
2034  *
2035  * \param ssl      SSL context
2036  */
2037 void mbedtls_ssl_init(mbedtls_ssl_context *ssl);
2038 
2039 /**
2040  * \brief          Set up an SSL context for use
2041  *
2042  * \note           No copy of the configuration context is made, it can be
2043  *                 shared by many mbedtls_ssl_context structures.
2044  *
2045  * \warning        The conf structure will be accessed during the session.
2046  *                 It must not be modified or freed as long as the session
2047  *                 is active.
2048  *
2049  * \warning        This function must be called exactly once per context.
2050  *                 Calling mbedtls_ssl_setup again is not supported, even
2051  *                 if no session is active.
2052  *
2053  * \warning        After setting up a client context, if certificate-based
2054  *                 authentication is enabled, you should call
2055  *                 mbedtls_ssl_set_hostname() to specifiy the expected
2056  *                 name of the server. Without this, in most scenarios,
2057  *                 the TLS connection is insecure. See
2058  *                 #MBEDTLS_ERR_SSL_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME
2059  *                 for more information.
2060  *
2061  * \note           If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
2062  *                 subsystem must have been initialized by calling
2063  *                 psa_crypto_init() before calling this function.
2064  *
2065  * \param ssl      SSL context
2066  * \param conf     SSL configuration to use
2067  *
2068  * \return         0 if successful, or MBEDTLS_ERR_SSL_ALLOC_FAILED if
2069  *                 memory allocation failed
2070  */
2071 int mbedtls_ssl_setup(mbedtls_ssl_context *ssl,
2072                       const mbedtls_ssl_config *conf);
2073 
2074 /**
2075  * \brief          Reset an already initialized SSL context for re-use
2076  *                 while retaining application-set variables, function
2077  *                 pointers and data.
2078  *
2079  * \param ssl      SSL context
2080  * \return         0 if successful, or MBEDTLS_ERR_SSL_ALLOC_FAILED or
2081                    MBEDTLS_ERR_SSL_HW_ACCEL_FAILED
2082  */
2083 int mbedtls_ssl_session_reset(mbedtls_ssl_context *ssl);
2084 
2085 /**
2086  * \brief          Set the current endpoint type
2087  *
2088  * \param conf     SSL configuration
2089  * \param endpoint must be MBEDTLS_SSL_IS_CLIENT or MBEDTLS_SSL_IS_SERVER
2090  */
2091 void mbedtls_ssl_conf_endpoint(mbedtls_ssl_config *conf, int endpoint);
2092 
2093 /**
2094  * \brief          Get the current endpoint type
2095  *
2096  * \param conf     SSL configuration
2097  *
2098  * \return         Endpoint type, either MBEDTLS_SSL_IS_CLIENT
2099  *                 or MBEDTLS_SSL_IS_SERVER
2100  */
mbedtls_ssl_conf_get_endpoint(const mbedtls_ssl_config * conf)2101 static inline int mbedtls_ssl_conf_get_endpoint(const mbedtls_ssl_config *conf)
2102 {
2103     return conf->MBEDTLS_PRIVATE(endpoint);
2104 }
2105 
2106 /**
2107  * \brief           Set the transport type (TLS or DTLS).
2108  *                  Default: TLS
2109  *
2110  * \note            For DTLS, you must either provide a recv callback that
2111  *                  doesn't block, or one that handles timeouts, see
2112  *                  \c mbedtls_ssl_set_bio(). You also need to provide timer
2113  *                  callbacks with \c mbedtls_ssl_set_timer_cb().
2114  *
2115  * \param conf      SSL configuration
2116  * \param transport transport type:
2117  *                  MBEDTLS_SSL_TRANSPORT_STREAM for TLS,
2118  *                  MBEDTLS_SSL_TRANSPORT_DATAGRAM for DTLS.
2119  */
2120 void mbedtls_ssl_conf_transport(mbedtls_ssl_config *conf, int transport);
2121 
2122 /**
2123  * \brief          Set the certificate verification mode
2124  *                 Default: NONE on server, REQUIRED on client
2125  *
2126  * \param conf     SSL configuration
2127  * \param authmode can be:
2128  *
2129  *  MBEDTLS_SSL_VERIFY_NONE:      peer certificate is not checked
2130  *                        (default on server)
2131  *                        (insecure on client)
2132  *
2133  *  MBEDTLS_SSL_VERIFY_OPTIONAL:  peer certificate is checked, however the
2134  *                        handshake continues even if verification failed;
2135  *                        mbedtls_ssl_get_verify_result() can be called after the
2136  *                        handshake is complete.
2137  *
2138  *  MBEDTLS_SSL_VERIFY_REQUIRED:  peer *must* present a valid certificate,
2139  *                        handshake is aborted if verification failed.
2140  *                        (default on client)
2141  *
2142  * \note On client, MBEDTLS_SSL_VERIFY_REQUIRED is the recommended mode.
2143  * With MBEDTLS_SSL_VERIFY_OPTIONAL, the user needs to call mbedtls_ssl_get_verify_result() at
2144  * the right time(s), which may not be obvious, while REQUIRED always perform
2145  * the verification as soon as possible. For example, REQUIRED was protecting
2146  * against the "triple handshake" attack even before it was found.
2147  */
2148 void mbedtls_ssl_conf_authmode(mbedtls_ssl_config *conf, int authmode);
2149 
2150 #if defined(MBEDTLS_SSL_EARLY_DATA)
2151 /**
2152  * \brief    Set the early data mode
2153  *           Default: disabled on server and client
2154  *
2155  * \param conf   The SSL configuration to use.
2156  * \param early_data_enabled can be:
2157  *
2158  *  MBEDTLS_SSL_EARLY_DATA_DISABLED:
2159  *  Early data functionality is disabled. This is the default on client and
2160  *  server.
2161  *
2162  *  MBEDTLS_SSL_EARLY_DATA_ENABLED:
2163  *  Early data functionality is enabled and may be negotiated in the handshake.
2164  *  Application using early data functionality needs to be aware that the
2165  *  security properties for early data (also refered to as 0-RTT data) are
2166  *  weaker than those for other kinds of TLS data. See the documentation of
2167  *  mbedtls_ssl_write_early_data() and mbedtls_ssl_read_early_data() for more
2168  *  information.
2169  *  When early data functionality is enabled on server and only in that case,
2170  *  the call to one of the APIs that trigger or resume an handshake sequence,
2171  *  namely mbedtls_ssl_handshake(), mbedtls_ssl_handshake_step(),
2172  *  mbedtls_ssl_read() or mbedtls_ssl_write() may return with the error code
2173  *  MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA indicating that some early data have
2174  *  been received. To read the early data, call mbedtls_ssl_read_early_data()
2175  *  before calling the original function again.
2176  */
2177 void mbedtls_ssl_conf_early_data(mbedtls_ssl_config *conf,
2178                                  int early_data_enabled);
2179 
2180 #if defined(MBEDTLS_SSL_SRV_C)
2181 /**
2182  * \brief Set the maximum amount of 0-RTT data in bytes
2183  *        Default:  #MBEDTLS_SSL_MAX_EARLY_DATA_SIZE
2184  *
2185  *        This function sets the value of the max_early_data_size
2186  *        field of the early data indication extension included in
2187  *        the NewSessionTicket messages that the server may send.
2188  *
2189  *        The value defines the maximum amount of 0-RTT data
2190  *        in bytes that a client will be allowed to send when using
2191  *        one of the tickets defined by the NewSessionTicket messages.
2192  *
2193  * \note When resuming a session using a ticket, if the server receives more
2194  *       early data than allowed for the ticket, it terminates the connection.
2195  *       The maximum amount of 0-RTT data should thus be large enough
2196  *       to allow a minimum of early data to be exchanged.
2197  *
2198  * \param[in] conf                  The SSL configuration to use.
2199  * \param[in] max_early_data_size   The maximum amount of 0-RTT data.
2200  *
2201  * \warning This interface DOES NOT influence/limit the amount of early data
2202  *          that can be received through previously created and issued tickets,
2203  *          which clients may have stored.
2204  */
2205 void mbedtls_ssl_conf_max_early_data_size(
2206     mbedtls_ssl_config *conf, uint32_t max_early_data_size);
2207 #endif /* MBEDTLS_SSL_SRV_C */
2208 
2209 #endif /* MBEDTLS_SSL_EARLY_DATA */
2210 
2211 #if defined(MBEDTLS_X509_CRT_PARSE_C)
2212 /**
2213  * \brief          Set the verification callback (Optional).
2214  *
2215  *                 If set, the provided verify callback is called for each
2216  *                 certificate in the peer's CRT chain, including the trusted
2217  *                 root. For more information, please see the documentation of
2218  *                 \c mbedtls_x509_crt_verify().
2219  *
2220  * \note           For per context callbacks and contexts, please use
2221  *                 mbedtls_ssl_set_verify() instead.
2222  *
2223  * \param conf     The SSL configuration to use.
2224  * \param f_vrfy   The verification callback to use during CRT verification.
2225  * \param p_vrfy   The opaque context to be passed to the callback.
2226  */
2227 void mbedtls_ssl_conf_verify(mbedtls_ssl_config *conf,
2228                              int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
2229                              void *p_vrfy);
2230 #endif /* MBEDTLS_X509_CRT_PARSE_C */
2231 
2232 /**
2233  * \brief          Set the random number generator callback
2234  *
2235  * \param conf     SSL configuration
2236  * \param f_rng    RNG function (mandatory)
2237  * \param p_rng    RNG parameter
2238  */
2239 void mbedtls_ssl_conf_rng(mbedtls_ssl_config *conf,
2240                           int (*f_rng)(void *, unsigned char *, size_t),
2241                           void *p_rng);
2242 
2243 /**
2244  * \brief          Set the debug callback
2245  *
2246  *                 The callback has the following argument:
2247  *                 void *           opaque context for the callback
2248  *                 int              debug level
2249  *                 const char *     file name
2250  *                 int              line number
2251  *                 const char *     message
2252  *
2253  * \param conf     SSL configuration
2254  * \param f_dbg    debug function
2255  * \param p_dbg    debug parameter
2256  */
2257 void mbedtls_ssl_conf_dbg(mbedtls_ssl_config *conf,
2258                           void (*f_dbg)(void *, int, const char *, int, const char *),
2259                           void  *p_dbg);
2260 
2261 /**
2262  * \brief          Return the SSL configuration structure associated
2263  *                 with the given SSL context.
2264  *
2265  * \note           The pointer returned by this function is guaranteed to
2266  *                 remain valid until the context is freed.
2267  *
2268  * \param ssl      The SSL context to query.
2269  * \return         Pointer to the SSL configuration associated with \p ssl.
2270  */
mbedtls_ssl_context_get_config(const mbedtls_ssl_context * ssl)2271 static inline const mbedtls_ssl_config *mbedtls_ssl_context_get_config(
2272     const mbedtls_ssl_context *ssl)
2273 {
2274     return ssl->MBEDTLS_PRIVATE(conf);
2275 }
2276 
2277 /**
2278  * \brief          Set the underlying BIO callbacks for write, read and
2279  *                 read-with-timeout.
2280  *
2281  * \param ssl      SSL context
2282  * \param p_bio    parameter (context) shared by BIO callbacks
2283  * \param f_send   write callback
2284  * \param f_recv   read callback
2285  * \param f_recv_timeout blocking read callback with timeout.
2286  *
2287  * \note           One of f_recv or f_recv_timeout can be NULL, in which case
2288  *                 the other is used. If both are non-NULL, f_recv_timeout is
2289  *                 used and f_recv is ignored (as if it were NULL).
2290  *
2291  * \note           The two most common use cases are:
2292  *                 - non-blocking I/O, f_recv != NULL, f_recv_timeout == NULL
2293  *                 - blocking I/O, f_recv == NULL, f_recv_timeout != NULL
2294  *
2295  * \note           For DTLS, you need to provide either a non-NULL
2296  *                 f_recv_timeout callback, or a f_recv that doesn't block.
2297  *
2298  * \note           See the documentations of \c mbedtls_ssl_send_t,
2299  *                 \c mbedtls_ssl_recv_t and \c mbedtls_ssl_recv_timeout_t for
2300  *                 the conventions those callbacks must follow.
2301  *
2302  * \note           On some platforms, net_sockets.c provides
2303  *                 \c mbedtls_net_send(), \c mbedtls_net_recv() and
2304  *                 \c mbedtls_net_recv_timeout() that are suitable to be used
2305  *                 here.
2306  */
2307 void mbedtls_ssl_set_bio(mbedtls_ssl_context *ssl,
2308                          void *p_bio,
2309                          mbedtls_ssl_send_t *f_send,
2310                          mbedtls_ssl_recv_t *f_recv,
2311                          mbedtls_ssl_recv_timeout_t *f_recv_timeout);
2312 
2313 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2314 
2315 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2316 
2317 
2318 /**
2319  * \brief             Configure the use of the Connection ID (CID)
2320  *                    extension in the next handshake.
2321  *
2322  *                    Reference: RFC 9146 (or draft-ietf-tls-dtls-connection-id-05
2323  *                    https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
2324  *                    for legacy version)
2325  *
2326  *                    The DTLS CID extension allows the reliable association of
2327  *                    DTLS records to DTLS connections across changes in the
2328  *                    underlying transport (changed IP and Port metadata) by
2329  *                    adding explicit connection identifiers (CIDs) to the
2330  *                    headers of encrypted DTLS records. The desired CIDs are
2331  *                    configured by the application layer and are exchanged in
2332  *                    new `ClientHello` / `ServerHello` extensions during the
2333  *                    handshake, where each side indicates the CID it wants the
2334  *                    peer to use when writing encrypted messages. The CIDs are
2335  *                    put to use once records get encrypted: the stack discards
2336  *                    any incoming records that don't include the configured CID
2337  *                    in their header, and adds the peer's requested CID to the
2338  *                    headers of outgoing messages.
2339  *
2340  *                    This API enables or disables the use of the CID extension
2341  *                    in the next handshake and sets the value of the CID to
2342  *                    be used for incoming messages.
2343  *
2344  * \param ssl         The SSL context to configure. This must be initialized.
2345  * \param enable      This value determines whether the CID extension should
2346  *                    be used or not. Possible values are:
2347  *                    - MBEDTLS_SSL_CID_ENABLED to enable the use of the CID.
2348  *                    - MBEDTLS_SSL_CID_DISABLED (default) to disable the use
2349  *                      of the CID.
2350  * \param own_cid     The address of the readable buffer holding the CID we want
2351  *                    the peer to use when sending encrypted messages to us.
2352  *                    This may be \c NULL if \p own_cid_len is \c 0.
2353  *                    This parameter is unused if \p enable is set to
2354  *                    MBEDTLS_SSL_CID_DISABLED.
2355  * \param own_cid_len The length of \p own_cid.
2356  *                    This parameter is unused if \p enable is set to
2357  *                    MBEDTLS_SSL_CID_DISABLED.
2358  *
2359  * \note              The value of \p own_cid_len must match the value of the
2360  *                    \c len parameter passed to mbedtls_ssl_conf_cid()
2361  *                    when configuring the ::mbedtls_ssl_config that \p ssl
2362  *                    is bound to.
2363  *
2364  * \note              This CID configuration applies to subsequent handshakes
2365  *                    performed on the SSL context \p ssl, but does not trigger
2366  *                    one. You still have to call `mbedtls_ssl_handshake()`
2367  *                    (for the initial handshake) or `mbedtls_ssl_renegotiate()`
2368  *                    (for a renegotiation handshake) explicitly after a
2369  *                    successful call to this function to run the handshake.
2370  *
2371  * \note              This call cannot guarantee that the use of the CID
2372  *                    will be successfully negotiated in the next handshake,
2373  *                    because the peer might not support it. Specifically:
2374  *                    - On the Client, enabling the use of the CID through
2375  *                      this call implies that the `ClientHello` in the next
2376  *                      handshake will include the CID extension, thereby
2377  *                      offering the use of the CID to the server. Only if
2378  *                      the `ServerHello` contains the CID extension, too,
2379  *                      the CID extension will actually be put to use.
2380  *                    - On the Server, enabling the use of the CID through
2381  *                      this call implies that the server will look for
2382  *                      the CID extension in a `ClientHello` from the client,
2383  *                      and, if present, reply with a CID extension in its
2384  *                      `ServerHello`.
2385  *
2386  * \note              To check whether the use of the CID was negotiated
2387  *                    after the subsequent handshake has completed, please
2388  *                    use the API mbedtls_ssl_get_peer_cid().
2389  *
2390  * \warning           If the use of the CID extension is enabled in this call
2391  *                    and the subsequent handshake negotiates its use, Mbed TLS
2392  *                    will silently drop every packet whose CID does not match
2393  *                    the CID configured in \p own_cid. It is the responsibility
2394  *                    of the user to adapt the underlying transport to take care
2395  *                    of CID-based demultiplexing before handing datagrams to
2396  *                    Mbed TLS.
2397  *
2398  * \return            \c 0 on success. In this case, the CID configuration
2399  *                    applies to the next handshake.
2400  * \return            A negative error code on failure.
2401  */
2402 int mbedtls_ssl_set_cid(mbedtls_ssl_context *ssl,
2403                         int enable,
2404                         unsigned char const *own_cid,
2405                         size_t own_cid_len);
2406 
2407 /**
2408  * \brief              Get information about our request for usage of the CID
2409  *                     extension in the current connection.
2410  *
2411  * \param ssl          The SSL context to query.
2412  * \param enabled      The address at which to store whether the CID extension
2413  *                     is requested to be used or not. If the CID is
2414  *                     requested, `*enabled` is set to
2415  *                     MBEDTLS_SSL_CID_ENABLED; otherwise, it is set to
2416  *                     MBEDTLS_SSL_CID_DISABLED.
2417  * \param own_cid      The address of the buffer in which to store our own
2418  *                     CID (if the CID extension is requested). This may be
2419  *                     \c NULL in case the value of our CID isn't needed. If
2420  *                     it is not \c NULL, \p own_cid_len must not be \c NULL.
2421  * \param own_cid_len  The address at which to store the size of our own CID
2422  *                     (if the CID extension is requested). This is also the
2423  *                     number of Bytes in \p own_cid that have been written.
2424  *                     This may be \c NULL in case the length of our own CID
2425  *                     isn't needed. If it is \c NULL, \p own_cid must be
2426  *                     \c NULL, too.
2427  *
2428  *\note                If we are requesting an empty CID this function sets
2429  *                     `*enabled` to #MBEDTLS_SSL_CID_DISABLED (the rationale
2430  *                     for this is that the resulting outcome is the
2431  *                     same as if the CID extensions wasn't requested).
2432  *
2433  * \return            \c 0 on success.
2434  * \return            A negative error code on failure.
2435  */
2436 int mbedtls_ssl_get_own_cid(mbedtls_ssl_context *ssl,
2437                             int *enabled,
2438                             unsigned char own_cid[MBEDTLS_SSL_CID_OUT_LEN_MAX],
2439                             size_t *own_cid_len);
2440 
2441 /**
2442  * \brief              Get information about the use of the CID extension
2443  *                     in the current connection.
2444  *
2445  * \param ssl          The SSL context to query.
2446  * \param enabled      The address at which to store whether the CID extension
2447  *                     is currently in use or not. If the CID is in use,
2448  *                     `*enabled` is set to MBEDTLS_SSL_CID_ENABLED;
2449  *                     otherwise, it is set to MBEDTLS_SSL_CID_DISABLED.
2450  * \param peer_cid     The address of the buffer in which to store the CID
2451  *                     chosen by the peer (if the CID extension is used).
2452  *                     This may be \c NULL in case the value of peer CID
2453  *                     isn't needed. If it is not \c NULL, \p peer_cid_len
2454  *                     must not be \c NULL.
2455  * \param peer_cid_len The address at which to store the size of the CID
2456  *                     chosen by the peer (if the CID extension is used).
2457  *                     This is also the number of Bytes in \p peer_cid that
2458  *                     have been written.
2459  *                     This may be \c NULL in case the length of the peer CID
2460  *                     isn't needed. If it is \c NULL, \p peer_cid must be
2461  *                     \c NULL, too.
2462  *
2463  * \note               This applies to the state of the CID negotiated in
2464  *                     the last complete handshake. If a handshake is in
2465  *                     progress, this function will attempt to complete
2466  *                     the handshake first.
2467  *
2468  * \note               If CID extensions have been exchanged but both client
2469  *                     and server chose to use an empty CID, this function
2470  *                     sets `*enabled` to #MBEDTLS_SSL_CID_DISABLED
2471  *                     (the rationale for this is that the resulting
2472  *                     communication is the same as if the CID extensions
2473  *                     hadn't been used).
2474  *
2475  * \return            \c 0 on success.
2476  * \return            A negative error code on failure.
2477  */
2478 int mbedtls_ssl_get_peer_cid(mbedtls_ssl_context *ssl,
2479                              int *enabled,
2480                              unsigned char peer_cid[MBEDTLS_SSL_CID_OUT_LEN_MAX],
2481                              size_t *peer_cid_len);
2482 
2483 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
2484 
2485 /**
2486  * \brief          Set the Maximum Transport Unit (MTU).
2487  *                 Special value: 0 means unset (no limit).
2488  *                 This represents the maximum size of a datagram payload
2489  *                 handled by the transport layer (usually UDP) as determined
2490  *                 by the network link and stack. In practice, this controls
2491  *                 the maximum size datagram the DTLS layer will pass to the
2492  *                 \c f_send() callback set using \c mbedtls_ssl_set_bio().
2493  *
2494  * \note           The limit on datagram size is converted to a limit on
2495  *                 record payload by subtracting the current overhead of
2496  *                 encapsulation and encryption/authentication if any.
2497  *
2498  * \note           This can be called at any point during the connection, for
2499  *                 example when a Path Maximum Transfer Unit (PMTU)
2500  *                 estimate becomes available from other sources,
2501  *                 such as lower (or higher) protocol layers.
2502  *
2503  * \note           This setting only controls the size of the packets we send,
2504  *                 and does not restrict the size of the datagrams we're
2505  *                 willing to receive. Client-side, you can request the
2506  *                 server to use smaller records with \c
2507  *                 mbedtls_ssl_conf_max_frag_len().
2508  *
2509  * \note           If both a MTU and a maximum fragment length have been
2510  *                 configured (or negotiated with the peer), the resulting
2511  *                 lower limit on record payload (see first note) is used.
2512  *
2513  * \note           This can only be used to decrease the maximum size
2514  *                 of datagrams (hence records, see first note) sent. It
2515  *                 cannot be used to increase the maximum size of records over
2516  *                 the limit set by #MBEDTLS_SSL_OUT_CONTENT_LEN.
2517  *
2518  * \note           Values lower than the current record layer expansion will
2519  *                 result in an error when trying to send data.
2520  *
2521  * \param ssl      SSL context
2522  * \param mtu      Value of the path MTU in bytes
2523  */
2524 void mbedtls_ssl_set_mtu(mbedtls_ssl_context *ssl, uint16_t mtu);
2525 #endif /* MBEDTLS_SSL_PROTO_DTLS */
2526 
2527 #if defined(MBEDTLS_X509_CRT_PARSE_C)
2528 /**
2529  * \brief          Set a connection-specific verification callback (optional).
2530  *
2531  *                 If set, the provided verify callback is called for each
2532  *                 certificate in the peer's CRT chain, including the trusted
2533  *                 root. For more information, please see the documentation of
2534  *                 \c mbedtls_x509_crt_verify().
2535  *
2536  * \note           This call is analogous to mbedtls_ssl_conf_verify() but
2537  *                 binds the verification callback and context to an SSL context
2538  *                 as opposed to an SSL configuration.
2539  *                 If mbedtls_ssl_conf_verify() and mbedtls_ssl_set_verify()
2540  *                 are both used, mbedtls_ssl_set_verify() takes precedence.
2541  *
2542  * \param ssl      The SSL context to use.
2543  * \param f_vrfy   The verification callback to use during CRT verification.
2544  * \param p_vrfy   The opaque context to be passed to the callback.
2545  */
2546 void mbedtls_ssl_set_verify(mbedtls_ssl_context *ssl,
2547                             int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
2548                             void *p_vrfy);
2549 #endif /* MBEDTLS_X509_CRT_PARSE_C */
2550 
2551 /**
2552  * \brief          Set the timeout period for mbedtls_ssl_read()
2553  *                 (Default: no timeout.)
2554  *
2555  * \param conf     SSL configuration context
2556  * \param timeout  Timeout value in milliseconds.
2557  *                 Use 0 for no timeout (default).
2558  *
2559  * \note           With blocking I/O, this will only work if a non-NULL
2560  *                 \c f_recv_timeout was set with \c mbedtls_ssl_set_bio().
2561  *                 With non-blocking I/O, this will only work if timer
2562  *                 callbacks were set with \c mbedtls_ssl_set_timer_cb().
2563  *
2564  * \note           With non-blocking I/O, you may also skip this function
2565  *                 altogether and handle timeouts at the application layer.
2566  */
2567 void mbedtls_ssl_conf_read_timeout(mbedtls_ssl_config *conf, uint32_t timeout);
2568 
2569 /**
2570  * \brief          Check whether a buffer contains a valid and authentic record
2571  *                 that has not been seen before. (DTLS only).
2572  *
2573  *                 This function does not change the user-visible state
2574  *                 of the SSL context. Its sole purpose is to provide
2575  *                 an indication of the legitimacy of an incoming record.
2576  *
2577  *                 This can be useful e.g. in distributed server environments
2578  *                 using the DTLS Connection ID feature, in which connections
2579  *                 might need to be passed between service instances on a change
2580  *                 of peer address, but where such disruptive operations should
2581  *                 only happen after the validity of incoming records has been
2582  *                 confirmed.
2583  *
2584  * \param ssl      The SSL context to use.
2585  * \param buf      The address of the buffer holding the record to be checked.
2586  *                 This must be a read/write buffer of length \p buflen Bytes.
2587  * \param buflen   The length of \p buf in Bytes.
2588  *
2589  * \note           This routine only checks whether the provided buffer begins
2590  *                 with a valid and authentic record that has not been seen
2591  *                 before, but does not check potential data following the
2592  *                 initial record. In particular, it is possible to pass DTLS
2593  *                 datagrams containing multiple records, in which case only
2594  *                 the first record is checked.
2595  *
2596  * \note           This function modifies the input buffer \p buf. If you need
2597  *                 to preserve the original record, you have to maintain a copy.
2598  *
2599  * \return         \c 0 if the record is valid and authentic and has not been
2600  *                 seen before.
2601  * \return         MBEDTLS_ERR_SSL_INVALID_MAC if the check completed
2602  *                 successfully but the record was found to be not authentic.
2603  * \return         MBEDTLS_ERR_SSL_INVALID_RECORD if the check completed
2604  *                 successfully but the record was found to be invalid for
2605  *                 a reason different from authenticity checking.
2606  * \return         MBEDTLS_ERR_SSL_UNEXPECTED_RECORD if the check completed
2607  *                 successfully but the record was found to be unexpected
2608  *                 in the state of the SSL context, including replayed records.
2609  * \return         Another negative error code on different kinds of failure.
2610  *                 In this case, the SSL context becomes unusable and needs
2611  *                 to be freed or reset before reuse.
2612  */
2613 int mbedtls_ssl_check_record(mbedtls_ssl_context const *ssl,
2614                              unsigned char *buf,
2615                              size_t buflen);
2616 
2617 /**
2618  * \brief          Set the timer callbacks (Mandatory for DTLS.)
2619  *
2620  * \param ssl      SSL context
2621  * \param p_timer  parameter (context) shared by timer callbacks
2622  * \param f_set_timer   set timer callback
2623  * \param f_get_timer   get timer callback. Must return:
2624  *
2625  * \note           See the documentation of \c mbedtls_ssl_set_timer_t and
2626  *                 \c mbedtls_ssl_get_timer_t for the conventions this pair of
2627  *                 callbacks must follow.
2628  *
2629  * \note           On some platforms, timing.c provides
2630  *                 \c mbedtls_timing_set_delay() and
2631  *                 \c mbedtls_timing_get_delay() that are suitable for using
2632  *                 here, except if using an event-driven style.
2633  *
2634  * \note           See also the "DTLS tutorial" article in our knowledge base.
2635  *                 https://mbed-tls.readthedocs.io/en/latest/kb/how-to/dtls-tutorial
2636  */
2637 void mbedtls_ssl_set_timer_cb(mbedtls_ssl_context *ssl,
2638                               void *p_timer,
2639                               mbedtls_ssl_set_timer_t *f_set_timer,
2640                               mbedtls_ssl_get_timer_t *f_get_timer);
2641 
2642 #if defined(MBEDTLS_SSL_SRV_C)
2643 /**
2644  * \brief           Set the certificate selection callback (server-side only).
2645  *
2646  *                  If set, the callback is always called for each handshake,
2647  *                  after `ClientHello` processing has finished.
2648  *
2649  * \param conf      The SSL configuration to register the callback with.
2650  * \param f_cert_cb The callback for selecting server certificate after
2651  *                  `ClientHello` processing has finished.
2652  */
mbedtls_ssl_conf_cert_cb(mbedtls_ssl_config * conf,mbedtls_ssl_hs_cb_t f_cert_cb)2653 static inline void mbedtls_ssl_conf_cert_cb(mbedtls_ssl_config *conf,
2654                                             mbedtls_ssl_hs_cb_t f_cert_cb)
2655 {
2656     conf->MBEDTLS_PRIVATE(f_cert_cb) = f_cert_cb;
2657 }
2658 #endif /* MBEDTLS_SSL_SRV_C */
2659 
2660 /**
2661  * \brief           Callback type: generate and write session ticket
2662  *
2663  * \note            This describes what a callback implementation should do.
2664  *                  This callback should generate an encrypted and
2665  *                  authenticated ticket for the session and write it to the
2666  *                  output buffer. Here, ticket means the opaque ticket part
2667  *                  of the NewSessionTicket structure of RFC 5077.
2668  *
2669  * \param p_ticket  Context for the callback
2670  * \param session   SSL session to be written in the ticket
2671  * \param start     Start of the output buffer
2672  * \param end       End of the output buffer
2673  * \param tlen      On exit, holds the length written
2674  * \param lifetime  On exit, holds the lifetime of the ticket in seconds
2675  *
2676  * \return          0 if successful, or
2677  *                  a specific MBEDTLS_ERR_XXX code.
2678  */
2679 typedef int mbedtls_ssl_ticket_write_t(void *p_ticket,
2680                                        const mbedtls_ssl_session *session,
2681                                        unsigned char *start,
2682                                        const unsigned char *end,
2683                                        size_t *tlen,
2684                                        uint32_t *lifetime);
2685 
2686 /**
2687  * \brief           Callback type: parse and load session ticket
2688  *
2689  * \note            This describes what a callback implementation should do.
2690  *                  This callback should parse a session ticket as generated
2691  *                  by the corresponding mbedtls_ssl_ticket_write_t function,
2692  *                  and, if the ticket is authentic and valid, load the
2693  *                  session.
2694  *
2695  * \note            The implementation is allowed to modify the first len
2696  *                  bytes of the input buffer, eg to use it as a temporary
2697  *                  area for the decrypted ticket contents.
2698  *
2699  * \param p_ticket  Context for the callback
2700  * \param session   SSL session to be loaded
2701  * \param buf       Start of the buffer containing the ticket
2702  * \param len       Length of the ticket.
2703  *
2704  * \return          0 if successful, or
2705  *                  MBEDTLS_ERR_SSL_INVALID_MAC if not authentic, or
2706  *                  MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED if expired, or
2707  *                  any other non-zero code for other failures.
2708  */
2709 typedef int mbedtls_ssl_ticket_parse_t(void *p_ticket,
2710                                        mbedtls_ssl_session *session,
2711                                        unsigned char *buf,
2712                                        size_t len);
2713 
2714 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C)
2715 /**
2716  * \brief           Configure SSL session ticket callbacks (server only).
2717  *                  (Default: none.)
2718  *
2719  * \note            On server, session tickets are enabled by providing
2720  *                  non-NULL callbacks.
2721  *
2722  * \note            On client, use \c mbedtls_ssl_conf_session_tickets().
2723  *
2724  * \param conf      SSL configuration context
2725  * \param f_ticket_write    Callback for writing a ticket
2726  * \param f_ticket_parse    Callback for parsing a ticket
2727  * \param p_ticket          Context shared by the two callbacks
2728  */
2729 void mbedtls_ssl_conf_session_tickets_cb(mbedtls_ssl_config *conf,
2730                                          mbedtls_ssl_ticket_write_t *f_ticket_write,
2731                                          mbedtls_ssl_ticket_parse_t *f_ticket_parse,
2732                                          void *p_ticket);
2733 
2734 #if defined(MBEDTLS_HAVE_TIME)
2735 /**
2736  * \brief Get the creation time of a session ticket.
2737  *
2738  * \note See the documentation of \c ticket_creation_time for information about
2739  *       the intended usage of this function.
2740  *
2741  * \param session  SSL session
2742  * \param ticket_creation_time  On exit, holds the ticket creation time in
2743  *                              milliseconds.
2744  *
2745  * \return         0 on success,
2746  *                 MBEDTLS_ERR_SSL_BAD_INPUT_DATA if an input is not valid.
2747  */
mbedtls_ssl_session_get_ticket_creation_time(mbedtls_ssl_session * session,mbedtls_ms_time_t * ticket_creation_time)2748 static inline int mbedtls_ssl_session_get_ticket_creation_time(
2749     mbedtls_ssl_session *session, mbedtls_ms_time_t *ticket_creation_time)
2750 {
2751     if (session == NULL || ticket_creation_time == NULL ||
2752         session->MBEDTLS_PRIVATE(endpoint) != MBEDTLS_SSL_IS_SERVER) {
2753         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
2754     }
2755 
2756     *ticket_creation_time = session->MBEDTLS_PRIVATE(ticket_creation_time);
2757 
2758     return 0;
2759 }
2760 #endif /* MBEDTLS_HAVE_TIME */
2761 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
2762 
2763 /**
2764  * \brief          Get the session-id buffer.
2765  *
2766  * \param session  SSL session.
2767  *
2768  * \return         The address of the session-id buffer.
2769  */
mbedtls_ssl_session_get_id(const mbedtls_ssl_session * session)2770 static inline unsigned const char (*mbedtls_ssl_session_get_id(const mbedtls_ssl_session *
2771                                                                session))[32]
2772 {
2773     return &session->MBEDTLS_PRIVATE(id);
2774 }
2775 
2776 /**
2777  * \brief          Get the size of the session-id.
2778  *
2779  * \param session  SSL session.
2780  *
2781  * \return         size_t size of session-id buffer.
2782  */
mbedtls_ssl_session_get_id_len(const mbedtls_ssl_session * session)2783 static inline size_t mbedtls_ssl_session_get_id_len(const mbedtls_ssl_session *session)
2784 {
2785     return session->MBEDTLS_PRIVATE(id_len);
2786 }
2787 
2788 /**
2789  * \brief          Get the ciphersuite-id.
2790  *
2791  * \param session  SSL session.
2792  *
2793  * \return         int represetation for ciphersuite.
2794  */
mbedtls_ssl_session_get_ciphersuite_id(const mbedtls_ssl_session * session)2795 static inline int mbedtls_ssl_session_get_ciphersuite_id(const mbedtls_ssl_session *session)
2796 {
2797     return session->MBEDTLS_PRIVATE(ciphersuite);
2798 }
2799 
2800 /**
2801  * \brief   Configure a key export callback.
2802  *          (Default: none.)
2803  *
2804  *          This API can be used for two purposes:
2805  *          - Debugging: Use this API to e.g. generate an NSSKeylog
2806  *            file and use it to inspect encrypted traffic in tools
2807  *            such as Wireshark.
2808  *          - Application-specific export: Use this API to implement
2809  *            key exporters, e.g. for EAP-TLS or DTLS-SRTP.
2810  *
2811  *
2812  * \param ssl            The SSL context to which the export
2813  *                       callback should be attached.
2814  * \param f_export_keys  The callback for the key export.
2815  * \param p_export_keys  The opaque context pointer to be passed to the
2816  *                       callback \p f_export_keys.
2817  */
2818 void mbedtls_ssl_set_export_keys_cb(mbedtls_ssl_context *ssl,
2819                                     mbedtls_ssl_export_keys_t *f_export_keys,
2820                                     void *p_export_keys);
2821 
2822 /** \brief Set the user data in an SSL configuration to a pointer.
2823  *
2824  * You can retrieve this value later with mbedtls_ssl_conf_get_user_data_p().
2825  *
2826  * \note The library stores \c p without accessing it. It is the responsibility
2827  *       of the caller to ensure that the pointer remains valid.
2828  *
2829  * \param conf           The SSL configuration context to modify.
2830  * \param p              The new value of the user data.
2831  */
mbedtls_ssl_conf_set_user_data_p(mbedtls_ssl_config * conf,void * p)2832 static inline void mbedtls_ssl_conf_set_user_data_p(
2833     mbedtls_ssl_config *conf,
2834     void *p)
2835 {
2836     conf->MBEDTLS_PRIVATE(user_data).p = p;
2837 }
2838 
2839 /** \brief Set the user data in an SSL configuration to an integer.
2840  *
2841  * You can retrieve this value later with mbedtls_ssl_conf_get_user_data_n().
2842  *
2843  * \param conf           The SSL configuration context to modify.
2844  * \param n              The new value of the user data.
2845  */
mbedtls_ssl_conf_set_user_data_n(mbedtls_ssl_config * conf,uintptr_t n)2846 static inline void mbedtls_ssl_conf_set_user_data_n(
2847     mbedtls_ssl_config *conf,
2848     uintptr_t n)
2849 {
2850     conf->MBEDTLS_PRIVATE(user_data).n = n;
2851 }
2852 
2853 /** \brief Retrieve the user data in an SSL configuration as a pointer.
2854  *
2855  * This is the value last set with mbedtls_ssl_conf_set_user_data_p(), or
2856  * \c NULL if mbedtls_ssl_conf_set_user_data_p() has not previously been
2857  * called. The value is undefined if mbedtls_ssl_conf_set_user_data_n() has
2858  * been called without a subsequent call to mbedtls_ssl_conf_set_user_data_p().
2859  *
2860  * \param conf           The SSL configuration context to modify.
2861  * \return               The current value of the user data.
2862  */
mbedtls_ssl_conf_get_user_data_p(mbedtls_ssl_config * conf)2863 static inline void *mbedtls_ssl_conf_get_user_data_p(
2864     mbedtls_ssl_config *conf)
2865 {
2866     return conf->MBEDTLS_PRIVATE(user_data).p;
2867 }
2868 
2869 /** \brief Retrieve the user data in an SSL configuration as an integer.
2870  *
2871  * This is the value last set with mbedtls_ssl_conf_set_user_data_n(), or
2872  * \c 0 if mbedtls_ssl_conf_set_user_data_n() has not previously been
2873  * called. The value is undefined if mbedtls_ssl_conf_set_user_data_p() has
2874  * been called without a subsequent call to mbedtls_ssl_conf_set_user_data_n().
2875  *
2876  * \param conf           The SSL configuration context to modify.
2877  * \return               The current value of the user data.
2878  */
mbedtls_ssl_conf_get_user_data_n(mbedtls_ssl_config * conf)2879 static inline uintptr_t mbedtls_ssl_conf_get_user_data_n(
2880     mbedtls_ssl_config *conf)
2881 {
2882     return conf->MBEDTLS_PRIVATE(user_data).n;
2883 }
2884 
2885 /** \brief Set the user data in an SSL context to a pointer.
2886  *
2887  * You can retrieve this value later with mbedtls_ssl_get_user_data_p().
2888  *
2889  * \note The library stores \c p without accessing it. It is the responsibility
2890  *       of the caller to ensure that the pointer remains valid.
2891  *
2892  * \param ssl            The SSL context to modify.
2893  * \param p              The new value of the user data.
2894  */
mbedtls_ssl_set_user_data_p(mbedtls_ssl_context * ssl,void * p)2895 static inline void mbedtls_ssl_set_user_data_p(
2896     mbedtls_ssl_context *ssl,
2897     void *p)
2898 {
2899     ssl->MBEDTLS_PRIVATE(user_data).p = p;
2900 }
2901 
2902 /** \brief Set the user data in an SSL context to an integer.
2903  *
2904  * You can retrieve this value later with mbedtls_ssl_get_user_data_n().
2905  *
2906  * \param ssl            The SSL context to modify.
2907  * \param n              The new value of the user data.
2908  */
mbedtls_ssl_set_user_data_n(mbedtls_ssl_context * ssl,uintptr_t n)2909 static inline void mbedtls_ssl_set_user_data_n(
2910     mbedtls_ssl_context *ssl,
2911     uintptr_t n)
2912 {
2913     ssl->MBEDTLS_PRIVATE(user_data).n = n;
2914 }
2915 
2916 /** \brief Retrieve the user data in an SSL context as a pointer.
2917  *
2918  * This is the value last set with mbedtls_ssl_set_user_data_p(), or
2919  * \c NULL if mbedtls_ssl_set_user_data_p() has not previously been
2920  * called. The value is undefined if mbedtls_ssl_set_user_data_n() has
2921  * been called without a subsequent call to mbedtls_ssl_set_user_data_p().
2922  *
2923  * \param ssl            The SSL context to modify.
2924  * \return               The current value of the user data.
2925  */
mbedtls_ssl_get_user_data_p(mbedtls_ssl_context * ssl)2926 static inline void *mbedtls_ssl_get_user_data_p(
2927     mbedtls_ssl_context *ssl)
2928 {
2929     return ssl->MBEDTLS_PRIVATE(user_data).p;
2930 }
2931 
2932 /** \brief Retrieve the user data in an SSL context as an integer.
2933  *
2934  * This is the value last set with mbedtls_ssl_set_user_data_n(), or
2935  * \c 0 if mbedtls_ssl_set_user_data_n() has not previously been
2936  * called. The value is undefined if mbedtls_ssl_set_user_data_p() has
2937  * been called without a subsequent call to mbedtls_ssl_set_user_data_n().
2938  *
2939  * \param ssl            The SSL context to modify.
2940  * \return               The current value of the user data.
2941  */
mbedtls_ssl_get_user_data_n(mbedtls_ssl_context * ssl)2942 static inline uintptr_t mbedtls_ssl_get_user_data_n(
2943     mbedtls_ssl_context *ssl)
2944 {
2945     return ssl->MBEDTLS_PRIVATE(user_data).n;
2946 }
2947 
2948 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
2949 /**
2950  * \brief           Configure asynchronous private key operation callbacks.
2951  *
2952  * \param conf              SSL configuration context
2953  * \param f_async_sign      Callback to start a signature operation. See
2954  *                          the description of ::mbedtls_ssl_async_sign_t
2955  *                          for more information. This may be \c NULL if the
2956  *                          external processor does not support any signature
2957  *                          operation; in this case the private key object
2958  *                          associated with the certificate will be used.
2959  * \param f_async_decrypt   Callback to start a decryption operation. See
2960  *                          the description of ::mbedtls_ssl_async_decrypt_t
2961  *                          for more information. This may be \c NULL if the
2962  *                          external processor does not support any decryption
2963  *                          operation; in this case the private key object
2964  *                          associated with the certificate will be used.
2965  * \param f_async_resume    Callback to resume an asynchronous operation. See
2966  *                          the description of ::mbedtls_ssl_async_resume_t
2967  *                          for more information. This may not be \c NULL unless
2968  *                          \p f_async_sign and \p f_async_decrypt are both
2969  *                          \c NULL.
2970  * \param f_async_cancel    Callback to cancel an asynchronous operation. See
2971  *                          the description of ::mbedtls_ssl_async_cancel_t
2972  *                          for more information. This may be \c NULL if
2973  *                          no cleanup is needed.
2974  * \param config_data       A pointer to configuration data which can be
2975  *                          retrieved with
2976  *                          mbedtls_ssl_conf_get_async_config_data(). The
2977  *                          library stores this value without dereferencing it.
2978  */
2979 void mbedtls_ssl_conf_async_private_cb(mbedtls_ssl_config *conf,
2980                                        mbedtls_ssl_async_sign_t *f_async_sign,
2981                                        mbedtls_ssl_async_decrypt_t *f_async_decrypt,
2982                                        mbedtls_ssl_async_resume_t *f_async_resume,
2983                                        mbedtls_ssl_async_cancel_t *f_async_cancel,
2984                                        void *config_data);
2985 
2986 /**
2987  * \brief           Retrieve the configuration data set by
2988  *                  mbedtls_ssl_conf_async_private_cb().
2989  *
2990  * \param conf      SSL configuration context
2991  * \return          The configuration data set by
2992  *                  mbedtls_ssl_conf_async_private_cb().
2993  */
2994 void *mbedtls_ssl_conf_get_async_config_data(const mbedtls_ssl_config *conf);
2995 
2996 /**
2997  * \brief           Retrieve the asynchronous operation user context.
2998  *
2999  * \note            This function may only be called while a handshake
3000  *                  is in progress.
3001  *
3002  * \param ssl       The SSL context to access.
3003  *
3004  * \return          The asynchronous operation user context that was last
3005  *                  set during the current handshake. If
3006  *                  mbedtls_ssl_set_async_operation_data() has not yet been
3007  *                  called during the current handshake, this function returns
3008  *                  \c NULL.
3009  */
3010 void *mbedtls_ssl_get_async_operation_data(const mbedtls_ssl_context *ssl);
3011 
3012 /**
3013  * \brief           Retrieve the asynchronous operation user context.
3014  *
3015  * \note            This function may only be called while a handshake
3016  *                  is in progress.
3017  *
3018  * \param ssl       The SSL context to access.
3019  * \param ctx       The new value of the asynchronous operation user context.
3020  *                  Call mbedtls_ssl_get_async_operation_data() later during the
3021  *                  same handshake to retrieve this value.
3022  */
3023 void mbedtls_ssl_set_async_operation_data(mbedtls_ssl_context *ssl,
3024                                           void *ctx);
3025 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3026 
3027 /**
3028  * \brief          Callback type: generate a cookie
3029  *
3030  * \param ctx      Context for the callback
3031  * \param p        Buffer to write to,
3032  *                 must be updated to point right after the cookie
3033  * \param end      Pointer to one past the end of the output buffer
3034  * \param info     Client ID info that was passed to
3035  *                 \c mbedtls_ssl_set_client_transport_id()
3036  * \param ilen     Length of info in bytes
3037  *
3038  * \return         The callback must return 0 on success,
3039  *                 or a negative error code.
3040  */
3041 typedef int mbedtls_ssl_cookie_write_t(void *ctx,
3042                                        unsigned char **p, unsigned char *end,
3043                                        const unsigned char *info, size_t ilen);
3044 
3045 /**
3046  * \brief          Callback type: verify a cookie
3047  *
3048  * \param ctx      Context for the callback
3049  * \param cookie   Cookie to verify
3050  * \param clen     Length of cookie
3051  * \param info     Client ID info that was passed to
3052  *                 \c mbedtls_ssl_set_client_transport_id()
3053  * \param ilen     Length of info in bytes
3054  *
3055  * \return         The callback must return 0 if cookie is valid,
3056  *                 or a negative error code.
3057  */
3058 typedef int mbedtls_ssl_cookie_check_t(void *ctx,
3059                                        const unsigned char *cookie, size_t clen,
3060                                        const unsigned char *info, size_t ilen);
3061 
3062 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
3063 /**
3064  * \brief           Register callbacks for DTLS cookies
3065  *                  (Server only. DTLS only.)
3066  *
3067  *                  Default: dummy callbacks that fail, in order to force you to
3068  *                  register working callbacks (and initialize their context).
3069  *
3070  *                  To disable HelloVerifyRequest, register NULL callbacks.
3071  *
3072  * \warning         Disabling hello verification allows your server to be used
3073  *                  for amplification in DoS attacks against other hosts.
3074  *                  Only disable if you known this can't happen in your
3075  *                  particular environment.
3076  *
3077  * \note            See comments on \c mbedtls_ssl_handshake() about handling
3078  *                  the MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED that is expected
3079  *                  on the first handshake attempt when this is enabled.
3080  *
3081  * \note            This is also necessary to handle client reconnection from
3082  *                  the same port as described in RFC 6347 section 4.2.8 (only
3083  *                  the variant with cookies is supported currently). See
3084  *                  comments on \c mbedtls_ssl_read() for details.
3085  *
3086  * \param conf              SSL configuration
3087  * \param f_cookie_write    Cookie write callback
3088  * \param f_cookie_check    Cookie check callback
3089  * \param p_cookie          Context for both callbacks
3090  */
3091 void mbedtls_ssl_conf_dtls_cookies(mbedtls_ssl_config *conf,
3092                                    mbedtls_ssl_cookie_write_t *f_cookie_write,
3093                                    mbedtls_ssl_cookie_check_t *f_cookie_check,
3094                                    void *p_cookie);
3095 
3096 /**
3097  * \brief          Set client's transport-level identification info.
3098  *                 (Server only. DTLS only.)
3099  *
3100  *                 This is usually the IP address (and port), but could be
3101  *                 anything identify the client depending on the underlying
3102  *                 network stack. Used for HelloVerifyRequest with DTLS.
3103  *                 This is *not* used to route the actual packets.
3104  *
3105  * \param ssl      SSL context
3106  * \param info     Transport-level info identifying the client (eg IP + port)
3107  * \param ilen     Length of info in bytes
3108  *
3109  * \note           An internal copy is made, so the info buffer can be reused.
3110  *
3111  * \return         0 on success,
3112  *                 MBEDTLS_ERR_SSL_BAD_INPUT_DATA if used on client,
3113  *                 MBEDTLS_ERR_SSL_ALLOC_FAILED if out of memory.
3114  */
3115 int mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context *ssl,
3116                                         const unsigned char *info,
3117                                         size_t ilen);
3118 
3119 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
3120 
3121 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
3122 /**
3123  * \brief          Enable or disable anti-replay protection for DTLS.
3124  *                 (DTLS only, no effect on TLS.)
3125  *                 Default: enabled.
3126  *
3127  * \param conf     SSL configuration
3128  * \param mode     MBEDTLS_SSL_ANTI_REPLAY_ENABLED or MBEDTLS_SSL_ANTI_REPLAY_DISABLED.
3129  *
3130  * \warning        Disabling this is a security risk unless the application
3131  *                 protocol handles duplicated packets in a safe way. You
3132  *                 should not disable this without careful consideration.
3133  *                 However, if your application already detects duplicated
3134  *                 packets and needs information about them to adjust its
3135  *                 transmission strategy, then you'll want to disable this.
3136  */
3137 void mbedtls_ssl_conf_dtls_anti_replay(mbedtls_ssl_config *conf, char mode);
3138 #endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */
3139 
3140 /**
3141  * \brief          Set a limit on the number of records with a bad MAC
3142  *                 before terminating the connection.
3143  *                 (DTLS only, no effect on TLS.)
3144  *                 Default: 0 (disabled).
3145  *
3146  * \param conf     SSL configuration
3147  * \param limit    Limit, or 0 to disable.
3148  *
3149  * \note           If the limit is N, then the connection is terminated when
3150  *                 the Nth non-authentic record is seen.
3151  *
3152  * \note           Records with an invalid header are not counted, only the
3153  *                 ones going through the authentication-decryption phase.
3154  *
3155  * \note           This is a security trade-off related to the fact that it's
3156  *                 often relatively easy for an active attacker to inject UDP
3157  *                 datagrams. On one hand, setting a low limit here makes it
3158  *                 easier for such an attacker to forcibly terminated a
3159  *                 connection. On the other hand, a high limit or no limit
3160  *                 might make us waste resources checking authentication on
3161  *                 many bogus packets.
3162  */
3163 void mbedtls_ssl_conf_dtls_badmac_limit(mbedtls_ssl_config *conf, unsigned limit);
3164 
3165 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3166 
3167 /**
3168  * \brief          Allow or disallow packing of multiple handshake records
3169  *                 within a single datagram.
3170  *
3171  * \param ssl           The SSL context to configure.
3172  * \param allow_packing This determines whether datagram packing may
3173  *                      be used or not. A value of \c 0 means that every
3174  *                      record will be sent in a separate datagram; a
3175  *                      value of \c 1 means that, if space permits,
3176  *                      multiple handshake messages (including CCS) belonging to
3177  *                      a single flight may be packed within a single datagram.
3178  *
3179  * \note           This is enabled by default and should only be disabled
3180  *                 for test purposes, or if datagram packing causes
3181  *                 interoperability issues with peers that don't support it.
3182  *
3183  * \note           Allowing datagram packing reduces the network load since
3184  *                 there's less overhead if multiple messages share the same
3185  *                 datagram. Also, it increases the handshake efficiency
3186  *                 since messages belonging to a single datagram will not
3187  *                 be reordered in transit, and so future message buffering
3188  *                 or flight retransmission (if no buffering is used) as
3189  *                 means to deal with reordering are needed less frequently.
3190  *
3191  * \note           Application records are not affected by this option and
3192  *                 are currently always sent in separate datagrams.
3193  *
3194  */
3195 void mbedtls_ssl_set_datagram_packing(mbedtls_ssl_context *ssl,
3196                                       unsigned allow_packing);
3197 
3198 /**
3199  * \brief          Set retransmit timeout values for the DTLS handshake.
3200  *                 (DTLS only, no effect on TLS.)
3201  *
3202  * \param conf     SSL configuration
3203  * \param min      Initial timeout value in milliseconds.
3204  *                 Default: 1000 (1 second).
3205  * \param max      Maximum timeout value in milliseconds.
3206  *                 Default: 60000 (60 seconds).
3207  *
3208  * \note           Default values are from RFC 6347 section 4.2.4.1.
3209  *
3210  * \note           The 'min' value should typically be slightly above the
3211  *                 expected round-trip time to your peer, plus whatever time
3212  *                 it takes for the peer to process the message. For example,
3213  *                 if your RTT is about 600ms and you peer needs up to 1s to
3214  *                 do the cryptographic operations in the handshake, then you
3215  *                 should set 'min' slightly above 1600. Lower values of 'min'
3216  *                 might cause spurious resends which waste network resources,
3217  *                 while larger value of 'min' will increase overall latency
3218  *                 on unreliable network links.
3219  *
3220  * \note           The more unreliable your network connection is, the larger
3221  *                 your max / min ratio needs to be in order to achieve
3222  *                 reliable handshakes.
3223  *
3224  * \note           Messages are retransmitted up to log2(ceil(max/min)) times.
3225  *                 For example, if min = 1s and max = 5s, the retransmit plan
3226  *                 goes: send ... 1s -> resend ... 2s -> resend ... 4s ->
3227  *                 resend ... 5s -> give up and return a timeout error.
3228  */
3229 void mbedtls_ssl_conf_handshake_timeout(mbedtls_ssl_config *conf, uint32_t min, uint32_t max);
3230 #endif /* MBEDTLS_SSL_PROTO_DTLS */
3231 
3232 #if defined(MBEDTLS_SSL_SRV_C)
3233 /**
3234  * \brief          Set the session cache callbacks (server-side only)
3235  *                 If not set, no session resuming is done (except if session
3236  *                 tickets are enabled too).
3237  *
3238  *                 The session cache has the responsibility to check for stale
3239  *                 entries based on timeout. See RFC 5246 for recommendations.
3240  *
3241  *                 Warning: session.peer_cert is cleared by the SSL/TLS layer on
3242  *                 connection shutdown, so do not cache the pointer! Either set
3243  *                 it to NULL or make a full copy of the certificate.
3244  *
3245  *                 The get callback is called once during the initial handshake
3246  *                 to enable session resuming. The get function has the
3247  *                 following parameters: (void *parameter, mbedtls_ssl_session *session)
3248  *                 If a valid entry is found, it should fill the master of
3249  *                 the session object with the cached values and return 0,
3250  *                 return 1 otherwise. Optionally peer_cert can be set as well
3251  *                 if it is properly present in cache entry.
3252  *
3253  *                 The set callback is called once during the initial handshake
3254  *                 to enable session resuming after the entire handshake has
3255  *                 been finished. The set function has the following parameters:
3256  *                 (void *parameter, const mbedtls_ssl_session *session). The function
3257  *                 should create a cache entry for future retrieval based on
3258  *                 the data in the session structure and should keep in mind
3259  *                 that the mbedtls_ssl_session object presented (and all its referenced
3260  *                 data) is cleared by the SSL/TLS layer when the connection is
3261  *                 terminated. It is recommended to add metadata to determine if
3262  *                 an entry is still valid in the future. Return 0 if
3263  *                 successfully cached, return 1 otherwise.
3264  *
3265  * \param conf           SSL configuration
3266  * \param p_cache        parameter (context) for both callbacks
3267  * \param f_get_cache    session get callback
3268  * \param f_set_cache    session set callback
3269  */
3270 void mbedtls_ssl_conf_session_cache(mbedtls_ssl_config *conf,
3271                                     void *p_cache,
3272                                     mbedtls_ssl_cache_get_t *f_get_cache,
3273                                     mbedtls_ssl_cache_set_t *f_set_cache);
3274 #endif /* MBEDTLS_SSL_SRV_C */
3275 
3276 #if defined(MBEDTLS_SSL_CLI_C)
3277 /**
3278  * \brief          Load a session for session resumption.
3279  *
3280  *                 Sessions loaded through this call will be considered
3281  *                 for session resumption in the next handshake.
3282  *
3283  * \note           Even if this call succeeds, it is not guaranteed that
3284  *                 the next handshake will indeed be shortened through the
3285  *                 use of session resumption: The server is always free
3286  *                 to reject any attempt for resumption and fall back to
3287  *                 a full handshake.
3288  *
3289  * \note           This function can handle a variety of mechanisms for session
3290  *                 resumption: For TLS 1.2, both session ID-based resumption and
3291  *                 ticket-based resumption will be considered. For TLS 1.3,
3292  *                 once implemented, sessions equate to tickets, and loading
3293  *                 one or more sessions via this call will lead to their
3294  *                 corresponding tickets being advertised as resumption PSKs
3295  *                 by the client.
3296  *
3297  * \note           Calling this function multiple times will only be useful
3298  *                 once TLS 1.3 is supported. For TLS 1.2 connections, this
3299  *                 function should be called at most once.
3300  *
3301  * \param ssl      The SSL context representing the connection which should
3302  *                 be attempted to be setup using session resumption. This
3303  *                 must be initialized via mbedtls_ssl_init() and bound to
3304  *                 an SSL configuration via mbedtls_ssl_setup(), but
3305  *                 the handshake must not yet have been started.
3306  * \param session  The session to be considered for session resumption.
3307  *                 This must be a session previously exported via
3308  *                 mbedtls_ssl_get_session(), and potentially serialized and
3309  *                 deserialized through mbedtls_ssl_session_save() and
3310  *                 mbedtls_ssl_session_load() in the meantime.
3311  *
3312  * \return         \c 0 if successful.
3313  * \return         \c MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if the session
3314  *                 could not be loaded because of an implementation limitation.
3315  *                 This error is non-fatal, and has no observable effect on
3316  *                 the SSL context or the session that was attempted to be loaded.
3317  * \return         Another negative error code on other kinds of failure.
3318  *
3319  * \sa             mbedtls_ssl_get_session()
3320  * \sa             mbedtls_ssl_session_load()
3321  */
3322 int mbedtls_ssl_set_session(mbedtls_ssl_context *ssl, const mbedtls_ssl_session *session);
3323 #endif /* MBEDTLS_SSL_CLI_C */
3324 
3325 /**
3326  * \brief          Load serialized session data into a session structure.
3327  *                 On client, this can be used for loading saved sessions
3328  *                 before resuming them with mbedtls_ssl_set_session().
3329  *                 On server, this can be used for alternative implementations
3330  *                 of session cache or session tickets.
3331  *
3332  * \warning        If a peer certificate chain is associated with the session,
3333  *                 the serialized state will only contain the peer's
3334  *                 end-entity certificate and the result of the chain
3335  *                 verification (unless verification was disabled), but not
3336  *                 the rest of the chain.
3337  *
3338  * \see            mbedtls_ssl_session_save()
3339  * \see            mbedtls_ssl_set_session()
3340  *
3341  * \param session  The session structure to be populated. It must have been
3342  *                 initialised with mbedtls_ssl_session_init() but not
3343  *                 populated yet.
3344  * \param buf      The buffer holding the serialized session data. It must be a
3345  *                 readable buffer of at least \p len bytes.
3346  * \param len      The size of the serialized data in bytes.
3347  *
3348  * \return         \c 0 if successful.
3349  * \return         #MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed.
3350  * \return         #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if input data is invalid.
3351  * \return         #MBEDTLS_ERR_SSL_VERSION_MISMATCH if the serialized data
3352  *                 was generated in a different version or configuration of
3353  *                 Mbed TLS.
3354  * \return         Another negative value for other kinds of errors (for
3355  *                 example, unsupported features in the embedded certificate).
3356  */
3357 int mbedtls_ssl_session_load(mbedtls_ssl_session *session,
3358                              const unsigned char *buf,
3359                              size_t len);
3360 
3361 /**
3362  * \brief          Save session structure as serialized data in a buffer.
3363  *                 On client, this can be used for saving session data,
3364  *                 potentially in non-volatile storage, for resuming later.
3365  *                 On server, this can be used for alternative implementations
3366  *                 of session cache or session tickets.
3367  *
3368  * \see            mbedtls_ssl_session_load()
3369  *
3370  * \param session  The session structure to be saved.
3371  * \param buf      The buffer to write the serialized data to. It must be a
3372  *                 writeable buffer of at least \p buf_len bytes, or may be \c
3373  *                 NULL if \p buf_len is \c 0.
3374  * \param buf_len  The number of bytes available for writing in \p buf.
3375  * \param olen     The size in bytes of the data that has been or would have
3376  *                 been written. It must point to a valid \c size_t.
3377  *
3378  * \note           \p olen is updated to the correct value regardless of
3379  *                 whether \p buf_len was large enough. This makes it possible
3380  *                 to determine the necessary size by calling this function
3381  *                 with \p buf set to \c NULL and \p buf_len to \c 0.
3382  *
3383  * \return         \c 0 if successful.
3384  * \return         #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL if \p buf is too small.
3385  */
3386 int mbedtls_ssl_session_save(const mbedtls_ssl_session *session,
3387                              unsigned char *buf,
3388                              size_t buf_len,
3389                              size_t *olen);
3390 
3391 /**
3392  * \brief               Set the list of allowed ciphersuites and the preference
3393  *                      order. First in the list has the highest preference.
3394  *
3395  *                      For TLS 1.2, the notion of ciphersuite determines both
3396  *                      the key exchange mechanism and the suite of symmetric
3397  *                      algorithms to be used during and after the handshake.
3398  *
3399  *                      For TLS 1.3 (in development), the notion of ciphersuite
3400  *                      only determines the suite of symmetric algorithms to be
3401  *                      used during and after the handshake, while key exchange
3402  *                      mechanisms are configured separately.
3403  *
3404  *                      In Mbed TLS, ciphersuites for both TLS 1.2 and TLS 1.3
3405  *                      are configured via this function. For users of TLS 1.3,
3406  *                      there will be separate API for the configuration of key
3407  *                      exchange mechanisms.
3408  *
3409  *                      The list of ciphersuites passed to this function may
3410  *                      contain a mixture of TLS 1.2 and TLS 1.3 ciphersuite
3411  *                      identifiers. This is useful if negotiation of TLS 1.3
3412  *                      should be attempted, but a fallback to TLS 1.2 would
3413  *                      be tolerated.
3414  *
3415  * \note                By default, the server chooses its preferred
3416  *                      ciphersuite among those that the client supports. If
3417  *                      mbedtls_ssl_conf_preference_order() is called to prefer
3418  *                      the client's preferences, the server instead chooses
3419  *                      the client's preferred ciphersuite among those that
3420  *                      the server supports.
3421  *
3422  * \warning             The ciphersuites array \p ciphersuites is not copied.
3423  *                      It must remain valid for the lifetime of the SSL
3424  *                      configuration \p conf.
3425  *
3426  * \param conf          The SSL configuration to modify.
3427  * \param ciphersuites  A 0-terminated list of IANA identifiers of supported
3428  *                      ciphersuites, accessible through \c MBEDTLS_TLS_XXX
3429  *                      and \c MBEDTLS_TLS1_3_XXX macros defined in
3430  *                      ssl_ciphersuites.h.
3431  */
3432 void mbedtls_ssl_conf_ciphersuites(mbedtls_ssl_config *conf,
3433                                    const int *ciphersuites);
3434 
3435 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
3436 /**
3437  * \brief Set the supported key exchange modes for TLS 1.3 connections.
3438  *
3439  *        In contrast to TLS 1.2, the ciphersuite concept in TLS 1.3 does not
3440  *        include the choice of key exchange mechanism. It is therefore not
3441  *        covered by the API mbedtls_ssl_conf_ciphersuites(). See the
3442  *        documentation of mbedtls_ssl_conf_ciphersuites() for more
3443  *        information on the ciphersuite concept in TLS 1.2 and TLS 1.3.
3444  *
3445  *        The present function is specific to TLS 1.3 and allows users to
3446  *        configure the set of supported key exchange mechanisms in TLS 1.3.
3447  *
3448  * \param conf       The SSL configuration the change should apply to.
3449  * \param kex_modes  A bitwise combination of one or more of the following:
3450  *                   - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK
3451  *                     This flag enables pure-PSK key exchanges.
3452  *                   - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL
3453  *                     This flag enables combined PSK-ephemeral key exchanges.
3454  *                   - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL
3455  *                     This flag enables pure-ephemeral key exchanges.
3456  *                   For convenience, the following pre-defined macros are
3457  *                   available for combinations of the above:
3458  *                   - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_ALL
3459  *                     Includes all of pure-PSK, PSK-ephemeral and pure-ephemeral.
3460  *                   - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL
3461  *                     Includes both pure-PSK and combined PSK-ephemeral
3462  *                     key exchanges, but excludes pure-ephemeral key exchanges.
3463  *                   - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ALL
3464  *                     Includes both pure-ephemeral and combined PSK-ephemeral
3465  *                     key exchanges.
3466  *
3467  * \note  If a PSK-based key exchange mode shall be supported, applications
3468  *        must also use the APIs mbedtls_ssl_conf_psk() or
3469  *        mbedtls_ssl_conf_psk_cb() or mbedtls_ssl_conf_psk_opaque()
3470  *        to configure the PSKs to be used.
3471  *
3472  * \note  If a pure-ephemeral key exchange mode shall be supported,
3473  *        server-side applications must also provide a certificate via
3474  *        mbedtls_ssl_conf_own_cert().
3475  *
3476  */
3477 
3478 void mbedtls_ssl_conf_tls13_key_exchange_modes(mbedtls_ssl_config *conf,
3479                                                const int kex_modes);
3480 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
3481 
3482 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
3483 #define MBEDTLS_SSL_UNEXPECTED_CID_IGNORE 0
3484 #define MBEDTLS_SSL_UNEXPECTED_CID_FAIL   1
3485 /**
3486  * \brief               Specify the length of Connection IDs for incoming
3487  *                      encrypted DTLS records, as well as the behaviour
3488  *                      on unexpected CIDs.
3489  *
3490  *                      By default, the CID length is set to \c 0,
3491  *                      and unexpected CIDs are silently ignored.
3492  *
3493  * \param conf          The SSL configuration to modify.
3494  * \param len           The length in Bytes of the CID fields in encrypted
3495  *                      DTLS records using the CID mechanism. This must
3496  *                      not be larger than #MBEDTLS_SSL_CID_OUT_LEN_MAX.
3497  * \param ignore_other_cids This determines the stack's behaviour when
3498  *                          receiving a record with an unexpected CID.
3499  *                          Possible values are:
3500  *                          - #MBEDTLS_SSL_UNEXPECTED_CID_IGNORE
3501  *                            In this case, the record is silently ignored.
3502  *                          - #MBEDTLS_SSL_UNEXPECTED_CID_FAIL
3503  *                            In this case, the stack fails with the specific
3504  *                            error code #MBEDTLS_ERR_SSL_UNEXPECTED_CID.
3505  *
3506  * \note                The CID specification allows implementations to either
3507  *                      use a common length for all incoming connection IDs or
3508  *                      allow variable-length incoming IDs. Mbed TLS currently
3509  *                      requires a common length for all connections sharing the
3510  *                      same SSL configuration; this allows simpler parsing of
3511  *                      record headers.
3512  *
3513  * \return              \c 0 on success.
3514  * \return              #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if \p len
3515  *                      is too large.
3516  */
3517 int mbedtls_ssl_conf_cid(mbedtls_ssl_config *conf, size_t len,
3518                          int ignore_other_cids);
3519 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
3520 
3521 #if defined(MBEDTLS_X509_CRT_PARSE_C)
3522 /**
3523  * \brief          Set the X.509 security profile used for verification
3524  *
3525  * \note           The restrictions are enforced for all certificates in the
3526  *                 chain. However, signatures in the handshake are not covered
3527  *                 by this setting but by \b mbedtls_ssl_conf_sig_hashes().
3528  *
3529  * \param conf     SSL configuration
3530  * \param profile  Profile to use
3531  */
3532 void mbedtls_ssl_conf_cert_profile(mbedtls_ssl_config *conf,
3533                                    const mbedtls_x509_crt_profile *profile);
3534 
3535 /**
3536  * \brief          Set the data required to verify peer certificate
3537  *
3538  * \note           See \c mbedtls_x509_crt_verify() for notes regarding the
3539  *                 parameters ca_chain (maps to trust_ca for that function)
3540  *                 and ca_crl.
3541  *
3542  * \param conf     SSL configuration
3543  * \param ca_chain trusted CA chain (meaning all fully trusted top-level CAs)
3544  * \param ca_crl   trusted CA CRLs
3545  */
3546 void mbedtls_ssl_conf_ca_chain(mbedtls_ssl_config *conf,
3547                                mbedtls_x509_crt *ca_chain,
3548                                mbedtls_x509_crl *ca_crl);
3549 
3550 #if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
3551 /**
3552  * \brief          Set DN hints sent to client in CertificateRequest message
3553  *
3554  * \note           If not set, subject distinguished names (DNs) are taken
3555  *                 from \c mbedtls_ssl_conf_ca_chain()
3556  *                 or \c mbedtls_ssl_set_hs_ca_chain())
3557  *
3558  * \param conf     SSL configuration
3559  * \param crt      crt chain whose subject DNs are issuer DNs of client certs
3560  *                 from which the client should select client peer certificate.
3561  */
3562 static inline
mbedtls_ssl_conf_dn_hints(mbedtls_ssl_config * conf,const mbedtls_x509_crt * crt)3563 void mbedtls_ssl_conf_dn_hints(mbedtls_ssl_config *conf,
3564                                const mbedtls_x509_crt *crt)
3565 {
3566     conf->MBEDTLS_PRIVATE(dn_hints) = crt;
3567 }
3568 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
3569 
3570 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
3571 /**
3572  * \brief          Set the trusted certificate callback.
3573  *
3574  *                 This API allows to register the set of trusted certificates
3575  *                 through a callback, instead of a linked list as configured
3576  *                 by mbedtls_ssl_conf_ca_chain().
3577  *
3578  *                 This is useful for example in contexts where a large number
3579  *                 of CAs are used, and the inefficiency of maintaining them
3580  *                 in a linked list cannot be tolerated. It is also useful when
3581  *                 the set of trusted CAs needs to be modified frequently.
3582  *
3583  *                 See the documentation of `mbedtls_x509_crt_ca_cb_t` for
3584  *                 more information.
3585  *
3586  * \param conf     The SSL configuration to register the callback with.
3587  * \param f_ca_cb  The trusted certificate callback to use when verifying
3588  *                 certificate chains.
3589  * \param p_ca_cb  The context to be passed to \p f_ca_cb (for example,
3590  *                 a reference to a trusted CA database).
3591  *
3592  * \note           This API is incompatible with mbedtls_ssl_conf_ca_chain():
3593  *                 Any call to this function overwrites the values set through
3594  *                 earlier calls to mbedtls_ssl_conf_ca_chain() or
3595  *                 mbedtls_ssl_conf_ca_cb().
3596  *
3597  * \note           This API is incompatible with CA indication in
3598  *                 CertificateRequest messages: A server-side SSL context which
3599  *                 is bound to an SSL configuration that uses a CA callback
3600  *                 configured via mbedtls_ssl_conf_ca_cb(), and which requires
3601  *                 client authentication, will send an empty CA list in the
3602  *                 corresponding CertificateRequest message.
3603  *
3604  * \note           This API is incompatible with mbedtls_ssl_set_hs_ca_chain():
3605  *                 If an SSL context is bound to an SSL configuration which uses
3606  *                 CA callbacks configured via mbedtls_ssl_conf_ca_cb(), then
3607  *                 calls to mbedtls_ssl_set_hs_ca_chain() have no effect.
3608  *
3609  * \note           The use of this API disables the use of restartable ECC
3610  *                 during X.509 CRT signature verification (but doesn't affect
3611  *                 other uses).
3612  *
3613  * \warning        This API is incompatible with the use of CRLs. Any call to
3614  *                 mbedtls_ssl_conf_ca_cb() unsets CRLs configured through
3615  *                 earlier calls to mbedtls_ssl_conf_ca_chain().
3616  *
3617  * \warning        In multi-threaded environments, the callback \p f_ca_cb
3618  *                 must be thread-safe, and it is the user's responsibility
3619  *                 to guarantee this (for example through a mutex
3620  *                 contained in the callback context pointed to by \p p_ca_cb).
3621  */
3622 void mbedtls_ssl_conf_ca_cb(mbedtls_ssl_config *conf,
3623                             mbedtls_x509_crt_ca_cb_t f_ca_cb,
3624                             void *p_ca_cb);
3625 #endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
3626 
3627 /**
3628  * \brief          Set own certificate chain and private key
3629  *
3630  * \note           own_cert should contain in order from the bottom up your
3631  *                 certificate chain. The top certificate (self-signed)
3632  *                 can be omitted.
3633  *
3634  * \note           On server, this function can be called multiple times to
3635  *                 provision more than one cert/key pair (eg one ECDSA, one
3636  *                 RSA with SHA-256, one RSA with SHA-1). An adequate
3637  *                 certificate will be selected according to the client's
3638  *                 advertised capabilities. In case multiple certificates are
3639  *                 adequate, preference is given to the one set by the first
3640  *                 call to this function, then second, etc.
3641  *
3642  * \note           On client, only the first call has any effect. That is,
3643  *                 only one client certificate can be provisioned. The
3644  *                 server's preferences in its CertificateRequest message will
3645  *                 be ignored and our only cert will be sent regardless of
3646  *                 whether it matches those preferences - the server can then
3647  *                 decide what it wants to do with it.
3648  *
3649  * \note           The provided \p pk_key needs to match the public key in the
3650  *                 first certificate in \p own_cert, or all handshakes using
3651  *                 that certificate will fail. It is your responsibility
3652  *                 to ensure that; this function will not perform any check.
3653  *                 You may use mbedtls_pk_check_pair() in order to perform
3654  *                 this check yourself, but be aware that this function can
3655  *                 be computationally expensive on some key types.
3656  *
3657  * \param conf     SSL configuration
3658  * \param own_cert own public certificate chain
3659  * \param pk_key   own private key
3660  *
3661  * \return         0 on success or MBEDTLS_ERR_SSL_ALLOC_FAILED
3662  */
3663 int mbedtls_ssl_conf_own_cert(mbedtls_ssl_config *conf,
3664                               mbedtls_x509_crt *own_cert,
3665                               mbedtls_pk_context *pk_key);
3666 #endif /* MBEDTLS_X509_CRT_PARSE_C */
3667 
3668 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED)
3669 /**
3670  * \brief          Configure pre-shared keys (PSKs) and their
3671  *                 identities to be used in PSK-based ciphersuites.
3672  *
3673  *                 Only one PSK can be registered, through either
3674  *                 mbedtls_ssl_conf_psk() or mbedtls_ssl_conf_psk_opaque().
3675  *                 If you attempt to register more than one PSK, this function
3676  *                 fails, though this may change in future versions, which
3677  *                 may add support for multiple PSKs.
3678  *
3679  * \note           This is mainly useful for clients. Servers will usually
3680  *                 want to use \c mbedtls_ssl_conf_psk_cb() instead.
3681  *
3682  * \note           A PSK set by \c mbedtls_ssl_set_hs_psk() in the PSK callback
3683  *                 takes precedence over a PSK configured by this function.
3684  *
3685  * \param conf     The SSL configuration to register the PSK with.
3686  * \param psk      The pointer to the pre-shared key to use.
3687  * \param psk_len  The length of the pre-shared key in bytes.
3688  * \param psk_identity      The pointer to the pre-shared key identity.
3689  * \param psk_identity_len  The length of the pre-shared key identity
3690  *                          in bytes.
3691  *
3692  * \note           The PSK and its identity are copied internally and
3693  *                 hence need not be preserved by the caller for the lifetime
3694  *                 of the SSL configuration.
3695  *
3696  * \return         \c 0 if successful.
3697  * \return         #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no more PSKs
3698  *                 can be configured. In this case, the old PSK(s) remain intact.
3699  * \return         Another negative error code on other kinds of failure.
3700  */
3701 int mbedtls_ssl_conf_psk(mbedtls_ssl_config *conf,
3702                          const unsigned char *psk, size_t psk_len,
3703                          const unsigned char *psk_identity, size_t psk_identity_len);
3704 
3705 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3706 /**
3707  * \brief          Configure one or more opaque pre-shared keys (PSKs) and
3708  *                 their identities to be used in PSK-based ciphersuites.
3709  *
3710  *                 Only one PSK can be registered, through either
3711  *                 mbedtls_ssl_conf_psk() or mbedtls_ssl_conf_psk_opaque().
3712  *                 If you attempt to register more than one PSK, this function
3713  *                 fails, though this may change in future versions, which
3714  *                 may add support for multiple PSKs.
3715  *
3716  * \note           This is mainly useful for clients. Servers will usually
3717  *                 want to use \c mbedtls_ssl_conf_psk_cb() instead.
3718  *
3719  * \note           An opaque PSK set by \c mbedtls_ssl_set_hs_psk_opaque() in
3720  *                 the PSK callback takes precedence over an opaque PSK
3721  *                 configured by this function.
3722  *
3723  * \param conf     The SSL configuration to register the PSK with.
3724  * \param psk      The identifier of the key slot holding the PSK.
3725  *                 Until \p conf is destroyed or this function is successfully
3726  *                 called again, the key slot \p psk must be populated with a
3727  *                 key of type PSA_ALG_CATEGORY_KEY_DERIVATION whose policy
3728  *                 allows its use for the key derivation algorithm applied
3729  *                 in the handshake.
3730  * \param psk_identity      The pointer to the pre-shared key identity.
3731  * \param psk_identity_len  The length of the pre-shared key identity
3732  *                          in bytes.
3733  *
3734  * \note           The PSK identity hint is copied internally and hence need
3735  *                 not be preserved by the caller for the lifetime of the
3736  *                 SSL configuration.
3737  *
3738  * \return         \c 0 if successful.
3739  * \return         #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no more PSKs
3740  *                 can be configured. In this case, the old PSK(s) remain intact.
3741  * \return         Another negative error code on other kinds of failure.
3742  */
3743 int mbedtls_ssl_conf_psk_opaque(mbedtls_ssl_config *conf,
3744                                 mbedtls_svc_key_id_t psk,
3745                                 const unsigned char *psk_identity,
3746                                 size_t psk_identity_len);
3747 #endif /* MBEDTLS_USE_PSA_CRYPTO */
3748 
3749 /**
3750  * \brief          Set the pre-shared Key (PSK) for the current handshake.
3751  *
3752  * \note           This should only be called inside the PSK callback,
3753  *                 i.e. the function passed to \c mbedtls_ssl_conf_psk_cb().
3754  *
3755  * \note           A PSK set by this function takes precedence over a PSK
3756  *                 configured by \c mbedtls_ssl_conf_psk().
3757  *
3758  * \param ssl      The SSL context to configure a PSK for.
3759  * \param psk      The pointer to the pre-shared key.
3760  * \param psk_len  The length of the pre-shared key in bytes.
3761  *
3762  * \return         \c 0 if successful.
3763  * \return         An \c MBEDTLS_ERR_SSL_XXX error code on failure.
3764  */
3765 int mbedtls_ssl_set_hs_psk(mbedtls_ssl_context *ssl,
3766                            const unsigned char *psk, size_t psk_len);
3767 
3768 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3769 /**
3770  * \brief          Set an opaque pre-shared Key (PSK) for the current handshake.
3771  *
3772  * \note           This should only be called inside the PSK callback,
3773  *                 i.e. the function passed to \c mbedtls_ssl_conf_psk_cb().
3774  *
3775  * \note           An opaque PSK set by this function takes precedence over an
3776  *                 opaque PSK configured by \c mbedtls_ssl_conf_psk_opaque().
3777  *
3778  * \param ssl      The SSL context to configure a PSK for.
3779  * \param psk      The identifier of the key slot holding the PSK.
3780  *                 For the duration of the current handshake, the key slot
3781  *                 must be populated with a key of type
3782  *                 PSA_ALG_CATEGORY_KEY_DERIVATION whose policy allows its
3783  *                 use for the key derivation algorithm
3784  *                 applied in the handshake.
3785  *
3786  * \return         \c 0 if successful.
3787  * \return         An \c MBEDTLS_ERR_SSL_XXX error code on failure.
3788  */
3789 int mbedtls_ssl_set_hs_psk_opaque(mbedtls_ssl_context *ssl,
3790                                   mbedtls_svc_key_id_t psk);
3791 #endif /* MBEDTLS_USE_PSA_CRYPTO */
3792 
3793 #if defined(MBEDTLS_SSL_SRV_C)
3794 /**
3795  * \brief          Set the PSK callback (server-side only).
3796  *
3797  *                 If set, the PSK callback is called for each
3798  *                 handshake where a PSK-based ciphersuite was negotiated.
3799  *                 The caller provides the identity received and wants to
3800  *                 receive the actual PSK data and length.
3801  *
3802  *                 The callback has the following parameters:
3803  *                 - \c void*: The opaque pointer \p p_psk.
3804  *                 - \c mbedtls_ssl_context*: The SSL context to which
3805  *                                            the operation applies.
3806  *                 - \c const unsigned char*: The PSK identity
3807  *                                            selected by the client.
3808  *                 - \c size_t: The length of the PSK identity
3809  *                              selected by the client.
3810  *
3811  *                 If a valid PSK identity is found, the callback should use
3812  *                 \c mbedtls_ssl_set_hs_psk() or
3813  *                 \c mbedtls_ssl_set_hs_psk_opaque()
3814  *                 on the SSL context to set the correct PSK and return \c 0.
3815  *                 Any other return value will result in a denied PSK identity.
3816  *
3817  * \note           A dynamic PSK (i.e. set by the PSK callback) takes
3818  *                 precedence over a static PSK (i.e. set by
3819  *                 \c mbedtls_ssl_conf_psk() or
3820  *                 \c mbedtls_ssl_conf_psk_opaque()).
3821  *                 This means that if you set a PSK callback using this
3822  *                 function, you don't need to set a PSK using
3823  *                 \c mbedtls_ssl_conf_psk() or
3824  *                 \c mbedtls_ssl_conf_psk_opaque()).
3825  *
3826  * \param conf     The SSL configuration to register the callback with.
3827  * \param f_psk    The callback for selecting and setting the PSK based
3828  *                 in the PSK identity chosen by the client.
3829  * \param p_psk    A pointer to an opaque structure to be passed to
3830  *                 the callback, for example a PSK store.
3831  */
3832 void mbedtls_ssl_conf_psk_cb(mbedtls_ssl_config *conf,
3833                              int (*f_psk)(void *, mbedtls_ssl_context *, const unsigned char *,
3834                                           size_t),
3835                              void *p_psk);
3836 #endif /* MBEDTLS_SSL_SRV_C */
3837 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED */
3838 
3839 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_SRV_C)
3840 /**
3841  * \brief          Set the Diffie-Hellman public P and G values
3842  *                 from big-endian binary presentations.
3843  *                 (Default values: MBEDTLS_DHM_RFC3526_MODP_2048_[PG]_BIN)
3844  *
3845  * \param conf     SSL configuration
3846  * \param dhm_P    Diffie-Hellman-Merkle modulus in big-endian binary form
3847  * \param P_len    Length of DHM modulus
3848  * \param dhm_G    Diffie-Hellman-Merkle generator in big-endian binary form
3849  * \param G_len    Length of DHM generator
3850  *
3851  * \return         0 if successful
3852  */
3853 int mbedtls_ssl_conf_dh_param_bin(mbedtls_ssl_config *conf,
3854                                   const unsigned char *dhm_P, size_t P_len,
3855                                   const unsigned char *dhm_G,  size_t G_len);
3856 
3857 /**
3858  * \brief          Set the Diffie-Hellman public P and G values,
3859  *                 read from existing context (server-side only)
3860  *
3861  * \param conf     SSL configuration
3862  * \param dhm_ctx  Diffie-Hellman-Merkle context
3863  *
3864  * \return         0 if successful
3865  */
3866 int mbedtls_ssl_conf_dh_param_ctx(mbedtls_ssl_config *conf, mbedtls_dhm_context *dhm_ctx);
3867 #endif /* MBEDTLS_DHM_C && defined(MBEDTLS_SSL_SRV_C) */
3868 
3869 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
3870 /**
3871  * \brief          Set the minimum length for Diffie-Hellman parameters.
3872  *                 (Client-side only.)
3873  *                 (Default: 1024 bits.)
3874  *
3875  * \param conf     SSL configuration
3876  * \param bitlen   Minimum bit length of the DHM prime
3877  */
3878 void mbedtls_ssl_conf_dhm_min_bitlen(mbedtls_ssl_config *conf,
3879                                      unsigned int bitlen);
3880 #endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_CLI_C */
3881 
3882 #if defined(MBEDTLS_ECP_C)
3883 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
3884 /**
3885  * \brief          Set the allowed curves in order of preference.
3886  *
3887  *                 On server: this only affects selection of the ECDHE curve;
3888  *                 the curves used for ECDH and ECDSA are determined by the
3889  *                 list of available certificates instead.
3890  *
3891  *                 On client: this affects the list of curves offered for any
3892  *                 use. The server can override our preference order.
3893  *
3894  *                 Both sides: limits the set of curves accepted for use in
3895  *                 ECDHE and in the peer's end-entity certificate.
3896  *
3897  * \deprecated     Superseded by mbedtls_ssl_conf_groups().
3898  *
3899  * \note           This has no influence on which curves are allowed inside the
3900  *                 certificate chains, see \c mbedtls_ssl_conf_cert_profile()
3901  *                 for that. For the end-entity certificate however, the key
3902  *                 will be accepted only if it is allowed both by this list
3903  *                 and by the cert profile.
3904  *
3905  * \note           This list should be ordered by decreasing preference
3906  *                 (preferred curve first).
3907  *
3908  * \note           The default list is the same set of curves that
3909  *                 #mbedtls_x509_crt_profile_default allows, plus
3910  *                 ECDHE-only curves selected according to the same criteria.
3911  *                 The order favors curves with the lowest resource usage.
3912  *
3913  * \note           New minor versions of Mbed TLS may extend this list,
3914  *                 for example if new curves are added to the library.
3915  *                 New minor versions of Mbed TLS will not remove items
3916  *                 from this list unless serious security concerns require it.
3917  *                 New minor versions of Mbed TLS may change the order in
3918  *                 keeping with the general principle of favoring the lowest
3919  *                 resource usage.
3920  *
3921  * \param conf     SSL configuration
3922  * \param curves   Ordered list of allowed curves,
3923  *                 terminated by MBEDTLS_ECP_DP_NONE.
3924  */
3925 void MBEDTLS_DEPRECATED mbedtls_ssl_conf_curves(mbedtls_ssl_config *conf,
3926                                                 const mbedtls_ecp_group_id *curves);
3927 #endif /* MBEDTLS_DEPRECATED_REMOVED */
3928 #endif /* MBEDTLS_ECP_C */
3929 
3930 /**
3931  * \brief          Set the allowed groups in order of preference.
3932  *
3933  *                 On server: This only affects the choice of key agreement mechanism
3934  *
3935  *                 On client: this affects the list of groups offered for any
3936  *                 use. The server can override our preference order.
3937  *
3938  *                 Both sides: limits the set of groups accepted for use in
3939  *                 key sharing.
3940  *
3941  * \note           This function replaces the deprecated mbedtls_ssl_conf_curves(),
3942  *                 which only allows ECP curves to be configured.
3943  *
3944  * \note           The most recent invocation of either mbedtls_ssl_conf_curves()
3945  *                 or mbedtls_ssl_conf_groups() nullifies all previous invocations
3946  *                 of both.
3947  *
3948  * \note           This list should be ordered by decreasing preference
3949  *                 (preferred group first).
3950  *
3951  * \note           When this function is not called, a default list is used,
3952  *                 consisting of all supported curves at 255 bits and above,
3953  *                 and all supported finite fields at 2048 bits and above.
3954  *                 The order favors groups with the lowest resource usage.
3955  *
3956  * \note           New minor versions of Mbed TLS will not remove items
3957  *                 from the default list unless serious security concerns require it.
3958  *                 New minor versions of Mbed TLS may change the order in
3959  *                 keeping with the general principle of favoring the lowest
3960  *                 resource usage.
3961  *
3962  * \param conf     SSL configuration
3963  * \param groups   List of allowed groups ordered by preference, terminated by 0.
3964  *                 Must contain valid IANA NamedGroup IDs (provided via either an integer
3965  *                 or using MBEDTLS_TLS1_3_NAMED_GROUP_XXX macros).
3966  */
3967 void mbedtls_ssl_conf_groups(mbedtls_ssl_config *conf,
3968                              const uint16_t *groups);
3969 
3970 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
3971 #if !defined(MBEDTLS_DEPRECATED_REMOVED) && defined(MBEDTLS_SSL_PROTO_TLS1_2)
3972 /**
3973  * \brief          Set the allowed hashes for signatures during the handshake.
3974  *
3975  * \note           This only affects which hashes are offered and can be used
3976  *                 for signatures during the handshake. Hashes for message
3977  *                 authentication and the TLS PRF are controlled by the
3978  *                 ciphersuite, see \c mbedtls_ssl_conf_ciphersuites(). Hashes
3979  *                 used for certificate signature are controlled by the
3980  *                 verification profile, see \c mbedtls_ssl_conf_cert_profile().
3981  *
3982  * \deprecated     Superseded by mbedtls_ssl_conf_sig_algs().
3983  *
3984  * \note           This list should be ordered by decreasing preference
3985  *                 (preferred hash first).
3986  *
3987  * \note           By default, all supported hashes whose length is at least
3988  *                 256 bits are allowed. This is the same set as the default
3989  *                 for certificate verification
3990  *                 (#mbedtls_x509_crt_profile_default).
3991  *                 The preference order is currently unspecified and may
3992  *                 change in future versions.
3993  *
3994  * \note           New minor versions of Mbed TLS may extend this list,
3995  *                 for example if new curves are added to the library.
3996  *                 New minor versions of Mbed TLS will not remove items
3997  *                 from this list unless serious security concerns require it.
3998  *
3999  * \param conf     SSL configuration
4000  * \param hashes   Ordered list of allowed signature hashes,
4001  *                 terminated by \c MBEDTLS_MD_NONE.
4002  */
4003 void MBEDTLS_DEPRECATED mbedtls_ssl_conf_sig_hashes(mbedtls_ssl_config *conf,
4004                                                     const int *hashes);
4005 #endif /* !MBEDTLS_DEPRECATED_REMOVED && MBEDTLS_SSL_PROTO_TLS1_2 */
4006 
4007 /**
4008  * \brief          Configure allowed signature algorithms for use in TLS
4009  *
4010  * \param conf     The SSL configuration to use.
4011  * \param sig_algs List of allowed IANA values for TLS 1.3 signature algorithms,
4012  *                 terminated by #MBEDTLS_TLS1_3_SIG_NONE. The list must remain
4013  *                 available throughout the lifetime of the conf object.
4014  *                 - For TLS 1.3, values of \c MBEDTLS_TLS1_3_SIG_XXXX should be
4015  *                   used.
4016  *                 - For TLS 1.2, values should be given as
4017  *                   "(HashAlgorithm << 8) | SignatureAlgorithm".
4018  */
4019 void mbedtls_ssl_conf_sig_algs(mbedtls_ssl_config *conf,
4020                                const uint16_t *sig_algs);
4021 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
4022 
4023 #if defined(MBEDTLS_X509_CRT_PARSE_C)
4024 /**
4025  * \brief          Set or reset the hostname to check against the received
4026  *                 peer certificate. On a client, this also sets the
4027  *                 ServerName TLS extension, if that extension is enabled.
4028  *                 On a TLS 1.3 client, this also sets the server name in
4029  *                 the session resumption ticket, if that feature is enabled.
4030  *
4031  * \param ssl      SSL context
4032  * \param hostname The server hostname. This may be \c NULL to clear
4033  *                 the hostname.
4034  *
4035  * \note           Maximum hostname length #MBEDTLS_SSL_MAX_HOST_NAME_LEN.
4036  *
4037  * \note           If the hostname is \c NULL on a client, then the server
4038  *                 is not authenticated: it only needs to have a valid
4039  *                 certificate, not a certificate matching its name.
4040  *                 Therefore you should always call this function on a client,
4041  *                 unless the connection is set up to only allow
4042  *                 pre-shared keys, or in scenarios where server
4043  *                 impersonation is not a concern. See the documentation of
4044  *                 #MBEDTLS_ERR_SSL_CERTIFICATE_VERIFICATION_WITHOUT_HOSTNAME
4045  *                 for more details.
4046  *
4047  * \return         0 if successful, #MBEDTLS_ERR_SSL_ALLOC_FAILED on
4048  *                 allocation failure, #MBEDTLS_ERR_SSL_BAD_INPUT_DATA on
4049  *                 too long input hostname.
4050  *
4051  *                 Hostname set to the one provided on success (cleared
4052  *                 when NULL). On allocation failure hostname is cleared.
4053  *                 On too long input failure, old hostname is unchanged.
4054  */
4055 int mbedtls_ssl_set_hostname(mbedtls_ssl_context *ssl, const char *hostname);
4056 
4057 /**
4058  * \brief          Get the hostname that checked against the received
4059  *                 server certificate. It is used to set the ServerName
4060  *                 TLS extension, too, if that extension is enabled.
4061  *                 (client-side only)
4062  *
4063  * \param ssl      SSL context
4064  *
4065  * \return         const pointer to the hostname value
4066  */
mbedtls_ssl_get_hostname(mbedtls_ssl_context * ssl)4067 static inline const char *mbedtls_ssl_get_hostname(mbedtls_ssl_context *ssl)
4068 {
4069     return ssl->MBEDTLS_PRIVATE(hostname);
4070 }
4071 #endif /* MBEDTLS_X509_CRT_PARSE_C */
4072 
4073 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
4074 /**
4075  * \brief          Retrieve SNI extension value for the current handshake.
4076  *                 Available in \c f_cert_cb of \c mbedtls_ssl_conf_cert_cb(),
4077  *                 this is the same value passed to \c f_sni callback of
4078  *                 \c mbedtls_ssl_conf_sni() and may be used instead of
4079  *                 \c mbedtls_ssl_conf_sni().
4080  *
4081  * \param ssl      SSL context
4082  * \param name_len pointer into which to store length of returned value.
4083  *                 0 if SNI extension is not present or not yet processed.
4084  *
4085  * \return         const pointer to SNI extension value.
4086  *                 - value is valid only when called in \c f_cert_cb
4087  *                   registered with \c mbedtls_ssl_conf_cert_cb().
4088  *                 - value is NULL if SNI extension is not present.
4089  *                 - value is not '\0'-terminated. Use \c name_len for len.
4090  *                 - value must not be freed.
4091  */
4092 const unsigned char *mbedtls_ssl_get_hs_sni(mbedtls_ssl_context *ssl,
4093                                             size_t *name_len);
4094 
4095 /**
4096  * \brief          Set own certificate and key for the current handshake
4097  *
4098  * \note           Same as \c mbedtls_ssl_conf_own_cert() but for use within
4099  *                 the SNI callback or the certificate selection callback.
4100  *
4101  * \note           Passing null \c own_cert clears the certificate list for
4102  *                 the current handshake.
4103  *
4104  * \param ssl      SSL context
4105  * \param own_cert own public certificate chain
4106  * \param pk_key   own private key
4107  *
4108  * \return         0 on success or MBEDTLS_ERR_SSL_ALLOC_FAILED
4109  */
4110 int mbedtls_ssl_set_hs_own_cert(mbedtls_ssl_context *ssl,
4111                                 mbedtls_x509_crt *own_cert,
4112                                 mbedtls_pk_context *pk_key);
4113 
4114 /**
4115  * \brief          Set the data required to verify peer certificate for the
4116  *                 current handshake
4117  *
4118  * \note           Same as \c mbedtls_ssl_conf_ca_chain() but for use within
4119  *                 the SNI callback or the certificate selection callback.
4120  *
4121  * \param ssl      SSL context
4122  * \param ca_chain trusted CA chain (meaning all fully trusted top-level CAs)
4123  * \param ca_crl   trusted CA CRLs
4124  */
4125 void mbedtls_ssl_set_hs_ca_chain(mbedtls_ssl_context *ssl,
4126                                  mbedtls_x509_crt *ca_chain,
4127                                  mbedtls_x509_crl *ca_crl);
4128 
4129 #if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
4130 /**
4131  * \brief          Set DN hints sent to client in CertificateRequest message
4132  *
4133  * \note           Same as \c mbedtls_ssl_conf_dn_hints() but for use within
4134  *                 the SNI callback or the certificate selection callback.
4135  *
4136  * \param ssl      SSL context
4137  * \param crt      crt chain whose subject DNs are issuer DNs of client certs
4138  *                 from which the client should select client peer certificate.
4139  */
4140 void mbedtls_ssl_set_hs_dn_hints(mbedtls_ssl_context *ssl,
4141                                  const mbedtls_x509_crt *crt);
4142 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
4143 
4144 /**
4145  * \brief          Set authmode for the current handshake.
4146  *
4147  * \note           Same as \c mbedtls_ssl_conf_authmode() but for use within
4148  *                 the SNI callback or the certificate selection callback.
4149  *
4150  * \param ssl      SSL context
4151  * \param authmode MBEDTLS_SSL_VERIFY_NONE, MBEDTLS_SSL_VERIFY_OPTIONAL or
4152  *                 MBEDTLS_SSL_VERIFY_REQUIRED
4153  */
4154 void mbedtls_ssl_set_hs_authmode(mbedtls_ssl_context *ssl,
4155                                  int authmode);
4156 
4157 /**
4158  * \brief          Set server side ServerName TLS extension callback
4159  *                 (optional, server-side only).
4160  *
4161  *                 If set, the ServerName callback is called whenever the
4162  *                 server receives a ServerName TLS extension from the client
4163  *                 during a handshake. The ServerName callback has the
4164  *                 following parameters: (void *parameter, mbedtls_ssl_context *ssl,
4165  *                 const unsigned char *hostname, size_t len). If a suitable
4166  *                 certificate is found, the callback must set the
4167  *                 certificate(s) and key(s) to use with \c
4168  *                 mbedtls_ssl_set_hs_own_cert() (can be called repeatedly),
4169  *                 and may optionally adjust the CA and associated CRL with \c
4170  *                 mbedtls_ssl_set_hs_ca_chain() as well as the client
4171  *                 authentication mode with \c mbedtls_ssl_set_hs_authmode(),
4172  *                 then must return 0. If no matching name is found, the
4173  *                 callback may return non-zero to abort the handshake.
4174  *
4175  * \param conf     SSL configuration
4176  * \param f_sni    verification function
4177  * \param p_sni    verification parameter
4178  */
4179 void mbedtls_ssl_conf_sni(mbedtls_ssl_config *conf,
4180                           int (*f_sni)(void *, mbedtls_ssl_context *, const unsigned char *,
4181                                        size_t),
4182                           void *p_sni);
4183 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
4184 
4185 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
4186 /**
4187  * \brief          Set the EC J-PAKE password for current handshake.
4188  *
4189  * \note           An internal copy is made, and destroyed as soon as the
4190  *                 handshake is completed, or when the SSL context is reset or
4191  *                 freed.
4192  *
4193  * \note           The SSL context needs to be already set up. The right place
4194  *                 to call this function is between \c mbedtls_ssl_setup() or
4195  *                 \c mbedtls_ssl_reset() and \c mbedtls_ssl_handshake().
4196  *                 Password cannot be empty (see RFC 8236).
4197  *
4198  * \param ssl      SSL context
4199  * \param pw       EC J-PAKE password (pre-shared secret). It cannot be empty
4200  * \param pw_len   length of pw in bytes
4201  *
4202  * \return         0 on success, or a negative error code.
4203  */
4204 int mbedtls_ssl_set_hs_ecjpake_password(mbedtls_ssl_context *ssl,
4205                                         const unsigned char *pw,
4206                                         size_t pw_len);
4207 
4208 /**
4209  * \brief          Set the EC J-PAKE opaque password for current handshake.
4210  *
4211  * \note           The key must remain valid until the handshake is over.
4212  *
4213  * \note           The SSL context needs to be already set up. The right place
4214  *                 to call this function is between \c mbedtls_ssl_setup() or
4215  *                 \c mbedtls_ssl_reset() and \c mbedtls_ssl_handshake().
4216  *
4217  * \param ssl      SSL context
4218  * \param pwd      EC J-PAKE opaque password
4219  *
4220  * \return         0 on success, or a negative error code.
4221  */
4222 int mbedtls_ssl_set_hs_ecjpake_password_opaque(mbedtls_ssl_context *ssl,
4223                                                mbedtls_svc_key_id_t pwd);
4224 #endif /*MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
4225 
4226 #if defined(MBEDTLS_SSL_ALPN)
4227 /**
4228  * \brief          Set the supported Application Layer Protocols.
4229  *
4230  * \param conf     SSL configuration
4231  * \param protos   Pointer to a NULL-terminated list of supported protocols,
4232  *                 in decreasing preference order. The pointer to the list is
4233  *                 recorded by the library for later reference as required, so
4234  *                 the lifetime of the table must be at least as long as the
4235  *                 lifetime of the SSL configuration structure.
4236  *
4237  * \return         0 on success, or MBEDTLS_ERR_SSL_BAD_INPUT_DATA.
4238  */
4239 int mbedtls_ssl_conf_alpn_protocols(mbedtls_ssl_config *conf, const char **protos);
4240 
4241 /**
4242  * \brief          Get the name of the negotiated Application Layer Protocol.
4243  *                 This function should be called after the handshake is
4244  *                 completed.
4245  *
4246  * \param ssl      SSL context
4247  *
4248  * \return         Protocol name, or NULL if no protocol was negotiated.
4249  */
4250 const char *mbedtls_ssl_get_alpn_protocol(const mbedtls_ssl_context *ssl);
4251 #endif /* MBEDTLS_SSL_ALPN */
4252 
4253 #if defined(MBEDTLS_SSL_DTLS_SRTP)
4254 #if defined(MBEDTLS_DEBUG_C)
mbedtls_ssl_get_srtp_profile_as_string(mbedtls_ssl_srtp_profile profile)4255 static inline const char *mbedtls_ssl_get_srtp_profile_as_string(mbedtls_ssl_srtp_profile profile)
4256 {
4257     switch (profile) {
4258         case MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80:
4259             return "MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80";
4260         case MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32:
4261             return "MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32";
4262         case MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80:
4263             return "MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80";
4264         case MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32:
4265             return "MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32";
4266         default: break;
4267     }
4268     return "";
4269 }
4270 #endif /* MBEDTLS_DEBUG_C */
4271 /**
4272  * \brief                   Manage support for mki(master key id) value
4273  *                          in use_srtp extension.
4274  *                          MKI is an optional part of SRTP used for key management
4275  *                          and re-keying. See RFC3711 section 3.1 for details.
4276  *                          The default value is
4277  *                          #MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED.
4278  *
4279  * \param conf              The SSL configuration to manage mki support.
4280  * \param support_mki_value Enable or disable mki usage. Values are
4281  *                          #MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED
4282  *                          or #MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED.
4283  */
4284 void mbedtls_ssl_conf_srtp_mki_value_supported(mbedtls_ssl_config *conf,
4285                                                int support_mki_value);
4286 
4287 /**
4288  * \brief                   Set the supported DTLS-SRTP protection profiles.
4289  *
4290  * \param conf              SSL configuration
4291  * \param profiles          Pointer to a List of MBEDTLS_TLS_SRTP_UNSET terminated
4292  *                          supported protection profiles
4293  *                          in decreasing preference order.
4294  *                          The pointer to the list is recorded by the library
4295  *                          for later reference as required, so the lifetime
4296  *                          of the table must be at least as long as the lifetime
4297  *                          of the SSL configuration structure.
4298  *                          The list must not hold more than
4299  *                          MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH elements
4300  *                          (excluding the terminating MBEDTLS_TLS_SRTP_UNSET).
4301  *
4302  * \return                  0 on success
4303  * \return                  #MBEDTLS_ERR_SSL_BAD_INPUT_DATA when the list of
4304  *                          protection profiles is incorrect.
4305  */
4306 int mbedtls_ssl_conf_dtls_srtp_protection_profiles
4307     (mbedtls_ssl_config *conf,
4308     const mbedtls_ssl_srtp_profile *profiles);
4309 
4310 /**
4311  * \brief                  Set the mki_value for the current DTLS-SRTP session.
4312  *
4313  * \param ssl              SSL context to use.
4314  * \param mki_value        The MKI value to set.
4315  * \param mki_len          The length of the MKI value.
4316  *
4317  * \note                   This function is relevant on client side only.
4318  *                         The server discovers the mki value during handshake.
4319  *                         A mki value set on server side using this function
4320  *                         is ignored.
4321  *
4322  * \return                 0 on success
4323  * \return                 #MBEDTLS_ERR_SSL_BAD_INPUT_DATA
4324  * \return                 #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE
4325  */
4326 int mbedtls_ssl_dtls_srtp_set_mki_value(mbedtls_ssl_context *ssl,
4327                                         unsigned char *mki_value,
4328                                         uint16_t mki_len);
4329 /**
4330  * \brief                  Get the negotiated DTLS-SRTP information:
4331  *                         Protection profile and MKI value.
4332  *
4333  * \warning                This function must be called after the handshake is
4334  *                         completed. The value returned by this function must
4335  *                         not be trusted or acted upon before the handshake completes.
4336  *
4337  * \param ssl              The SSL context to query.
4338  * \param dtls_srtp_info   The negotiated DTLS-SRTP information:
4339  *                         - Protection profile in use.
4340  *                         A direct mapping of the iana defined value for protection
4341  *                         profile on an uint16_t.
4342                    http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
4343  *                         #MBEDTLS_TLS_SRTP_UNSET if the use of SRTP was not negotiated
4344  *                         or peer's Hello packet was not parsed yet.
4345  *                         - mki size and value( if size is > 0 ).
4346  */
4347 void mbedtls_ssl_get_dtls_srtp_negotiation_result(const mbedtls_ssl_context *ssl,
4348                                                   mbedtls_dtls_srtp_info *dtls_srtp_info);
4349 #endif /* MBEDTLS_SSL_DTLS_SRTP */
4350 
4351 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
4352 /**
4353  * \brief          Set the maximum supported version sent from the client side
4354  *                 and/or accepted at the server side.
4355  *
4356  *                 See also the documentation of mbedtls_ssl_conf_min_version().
4357  *
4358  * \note           This ignores ciphersuites from higher versions.
4359  *
4360  * \note           This function is deprecated and has been replaced by
4361  *                 \c mbedtls_ssl_conf_max_tls_version().
4362  *
4363  * \param conf     SSL configuration
4364  * \param major    Major version number (#MBEDTLS_SSL_MAJOR_VERSION_3)
4365  * \param minor    Minor version number
4366  *                 (#MBEDTLS_SSL_MINOR_VERSION_3 for (D)TLS 1.2,
4367  *                 #MBEDTLS_SSL_MINOR_VERSION_4 for TLS 1.3)
4368  */
4369 void MBEDTLS_DEPRECATED mbedtls_ssl_conf_max_version(mbedtls_ssl_config *conf, int major,
4370                                                      int minor);
4371 #endif /* MBEDTLS_DEPRECATED_REMOVED */
4372 
4373 /**
4374  * \brief          Set the maximum supported version sent from the client side
4375  *                 and/or accepted at the server side.
4376  *
4377  * \note           After the handshake, you can call
4378  *                 mbedtls_ssl_get_version_number() to see what version was
4379  *                 negotiated.
4380  *
4381  * \param conf         SSL configuration
4382  * \param tls_version  TLS protocol version number (\c mbedtls_ssl_protocol_version)
4383  *                     (#MBEDTLS_SSL_VERSION_UNKNOWN is not valid)
4384  */
mbedtls_ssl_conf_max_tls_version(mbedtls_ssl_config * conf,mbedtls_ssl_protocol_version tls_version)4385 static inline void mbedtls_ssl_conf_max_tls_version(mbedtls_ssl_config *conf,
4386                                                     mbedtls_ssl_protocol_version tls_version)
4387 {
4388     conf->MBEDTLS_PRIVATE(max_tls_version) = tls_version;
4389 }
4390 
4391 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
4392 /**
4393  * \brief          Set the minimum accepted SSL/TLS protocol version
4394  *
4395  * \note           By default, all supported versions are accepted.
4396  *                 Future versions of the library may disable older
4397  *                 protocol versions by default if they become deprecated.
4398  *
4399  * \note           The following versions are supported (if enabled at
4400  *                 compile time):
4401  *                 - (D)TLS 1.2: \p major = #MBEDTLS_SSL_MAJOR_VERSION_3,
4402  *                   \p minor = #MBEDTLS_SSL_MINOR_VERSION_3
4403  *                 - TLS 1.3: \p major = #MBEDTLS_SSL_MAJOR_VERSION_3,
4404  *                   \p minor = #MBEDTLS_SSL_MINOR_VERSION_4
4405  *
4406  *                 Note that the numbers in the constant names are the
4407  *                 TLS internal protocol numbers, and the minor versions
4408  *                 differ by one from the human-readable versions!
4409  *
4410  * \note           Input outside of the SSL_MAX_XXXXX_VERSION and
4411  *                 SSL_MIN_XXXXX_VERSION range is ignored.
4412  *
4413  * \note           After the handshake, you can call
4414  *                 mbedtls_ssl_get_version_number() to see what version was
4415  *                 negotiated.
4416  *
4417  * \note           This function is deprecated and has been replaced by
4418  *                 \c mbedtls_ssl_conf_min_tls_version().
4419  *
4420  * \param conf     SSL configuration
4421  * \param major    Major version number (#MBEDTLS_SSL_MAJOR_VERSION_3)
4422  * \param minor    Minor version number
4423  *                 (#MBEDTLS_SSL_MINOR_VERSION_3 for (D)TLS 1.2,
4424  *                 #MBEDTLS_SSL_MINOR_VERSION_4 for TLS 1.3)
4425  */
4426 void MBEDTLS_DEPRECATED mbedtls_ssl_conf_min_version(mbedtls_ssl_config *conf, int major,
4427                                                      int minor);
4428 #endif /* MBEDTLS_DEPRECATED_REMOVED */
4429 
4430 /**
4431  * \brief          Set the minimum supported version sent from the client side
4432  *                 and/or accepted at the server side.
4433  *
4434  * \note           After the handshake, you can call
4435  *                 mbedtls_ssl_get_version_number() to see what version was
4436  *                 negotiated.
4437  *
4438  * \param conf         SSL configuration
4439  * \param tls_version  TLS protocol version number (\c mbedtls_ssl_protocol_version)
4440  *                     (#MBEDTLS_SSL_VERSION_UNKNOWN is not valid)
4441  */
mbedtls_ssl_conf_min_tls_version(mbedtls_ssl_config * conf,mbedtls_ssl_protocol_version tls_version)4442 static inline void mbedtls_ssl_conf_min_tls_version(mbedtls_ssl_config *conf,
4443                                                     mbedtls_ssl_protocol_version tls_version)
4444 {
4445     conf->MBEDTLS_PRIVATE(min_tls_version) = tls_version;
4446 }
4447 
4448 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
4449 /**
4450  * \brief           Enable or disable Encrypt-then-MAC
4451  *                  (Default: MBEDTLS_SSL_ETM_ENABLED)
4452  *
4453  * \note            This should always be enabled, it is a security
4454  *                  improvement, and should not cause any interoperability
4455  *                  issue (used only if the peer supports it too).
4456  *
4457  * \param conf      SSL configuration
4458  * \param etm       MBEDTLS_SSL_ETM_ENABLED or MBEDTLS_SSL_ETM_DISABLED
4459  */
4460 void mbedtls_ssl_conf_encrypt_then_mac(mbedtls_ssl_config *conf, char etm);
4461 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
4462 
4463 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
4464 /**
4465  * \brief           Enable or disable Extended Master Secret negotiation.
4466  *                  (Default: MBEDTLS_SSL_EXTENDED_MS_ENABLED)
4467  *
4468  * \note            This should always be enabled, it is a security fix to the
4469  *                  protocol, and should not cause any interoperability issue
4470  *                  (used only if the peer supports it too).
4471  *
4472  * \param conf      SSL configuration
4473  * \param ems       MBEDTLS_SSL_EXTENDED_MS_ENABLED or MBEDTLS_SSL_EXTENDED_MS_DISABLED
4474  */
4475 void mbedtls_ssl_conf_extended_master_secret(mbedtls_ssl_config *conf, char ems);
4476 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
4477 
4478 #if defined(MBEDTLS_SSL_SRV_C)
4479 /**
4480  * \brief          Whether to send a list of acceptable CAs in
4481  *                 CertificateRequest messages.
4482  *                 (Default: do send)
4483  *
4484  * \param conf     SSL configuration
4485  * \param cert_req_ca_list   MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED or
4486  *                          MBEDTLS_SSL_CERT_REQ_CA_LIST_DISABLED
4487  */
4488 void mbedtls_ssl_conf_cert_req_ca_list(mbedtls_ssl_config *conf,
4489                                        char cert_req_ca_list);
4490 #endif /* MBEDTLS_SSL_SRV_C */
4491 
4492 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
4493 /**
4494  * \brief          Set the maximum fragment length to emit and/or negotiate.
4495  *                 (Typical: the smaller of #MBEDTLS_SSL_IN_CONTENT_LEN and
4496  *                 #MBEDTLS_SSL_OUT_CONTENT_LEN, usually `2^14` bytes)
4497  *                 (Server: set maximum fragment length to emit,
4498  *                 usually negotiated by the client during handshake)
4499  *                 (Client: set maximum fragment length to emit *and*
4500  *                 negotiate with the server during handshake)
4501  *                 (Default: #MBEDTLS_SSL_MAX_FRAG_LEN_NONE)
4502  *
4503  * \note           On the client side, the maximum fragment length extension
4504  *                 *will not* be used, unless the maximum fragment length has
4505  *                 been set via this function to a value different than
4506  *                 #MBEDTLS_SSL_MAX_FRAG_LEN_NONE.
4507  *
4508  * \note           With TLS, this currently only affects ApplicationData (sent
4509  *                 with \c mbedtls_ssl_read()), not handshake messages.
4510  *                 With DTLS, this affects both ApplicationData and handshake.
4511  *
4512  * \note           This sets the maximum length for a record's payload,
4513  *                 excluding record overhead that will be added to it, see
4514  *                 \c mbedtls_ssl_get_record_expansion().
4515  *
4516  * \note           For DTLS, it is also possible to set a limit for the total
4517  *                 size of datagrams passed to the transport layer, including
4518  *                 record overhead, see \c mbedtls_ssl_set_mtu().
4519  *
4520  * \param conf     SSL configuration
4521  * \param mfl_code Code for maximum fragment length (allowed values:
4522  *                 MBEDTLS_SSL_MAX_FRAG_LEN_512,  MBEDTLS_SSL_MAX_FRAG_LEN_1024,
4523  *                 MBEDTLS_SSL_MAX_FRAG_LEN_2048, MBEDTLS_SSL_MAX_FRAG_LEN_4096)
4524  *
4525  * \return         0 if successful or MBEDTLS_ERR_SSL_BAD_INPUT_DATA
4526  */
4527 int mbedtls_ssl_conf_max_frag_len(mbedtls_ssl_config *conf, unsigned char mfl_code);
4528 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
4529 
4530 #if defined(MBEDTLS_SSL_SRV_C)
4531 /**
4532  * \brief          Pick the ciphersuites order according to the second parameter
4533  *                 in the SSL Server module (MBEDTLS_SSL_SRV_C).
4534  *                 (Default, if never called: MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_SERVER)
4535  *
4536  * \param conf     SSL configuration
4537  * \param order    Server or client (MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_SERVER
4538  *                                or MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_CLIENT)
4539  */
4540 void mbedtls_ssl_conf_preference_order(mbedtls_ssl_config *conf, int order);
4541 #endif /* MBEDTLS_SSL_SRV_C */
4542 
4543 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
4544     defined(MBEDTLS_SSL_CLI_C)
4545 /**
4546  * \brief          Enable / Disable session tickets (client only).
4547  *                 (Default: MBEDTLS_SSL_SESSION_TICKETS_ENABLED.)
4548  *
4549  * \note           On server, use \c mbedtls_ssl_conf_session_tickets_cb().
4550  *
4551  * \param conf     SSL configuration
4552  * \param use_tickets   Enable or disable (MBEDTLS_SSL_SESSION_TICKETS_ENABLED or
4553  *                                         MBEDTLS_SSL_SESSION_TICKETS_DISABLED)
4554  */
4555 void mbedtls_ssl_conf_session_tickets(mbedtls_ssl_config *conf, int use_tickets);
4556 #endif /* MBEDTLS_SSL_SESSION_TICKETS &&
4557           MBEDTLS_SSL_CLI_C */
4558 
4559 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
4560     defined(MBEDTLS_SSL_SRV_C) && \
4561     defined(MBEDTLS_SSL_PROTO_TLS1_3)
4562 /**
4563  * \brief   Number of NewSessionTicket messages for the server to send
4564  *          after handshake completion.
4565  *
4566  * \note    The default value is
4567  *          \c MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS.
4568  *
4569  * \note    In case of a session resumption, this setting only partially apply.
4570  *          At most one ticket is sent in that case to just renew the pool of
4571  *          tickets of the client. The rationale is to avoid the number of
4572  *          tickets on the server to become rapidly out of control when the
4573  *          server has the same configuration for all its connection instances.
4574  *
4575  * \param conf    SSL configuration
4576  * \param num_tickets    Number of NewSessionTicket.
4577  *
4578  */
4579 void mbedtls_ssl_conf_new_session_tickets(mbedtls_ssl_config *conf,
4580                                           uint16_t num_tickets);
4581 #endif /* MBEDTLS_SSL_SESSION_TICKETS &&
4582           MBEDTLS_SSL_SRV_C &&
4583           MBEDTLS_SSL_PROTO_TLS1_3*/
4584 
4585 #if defined(MBEDTLS_SSL_RENEGOTIATION)
4586 /**
4587  * \brief          Enable / Disable renegotiation support for connection when
4588  *                 initiated by peer
4589  *                 (Default: MBEDTLS_SSL_RENEGOTIATION_DISABLED)
4590  *
4591  * \warning        It is recommended to always disable renegotiation unless you
4592  *                 know you need it and you know what you're doing. In the
4593  *                 past, there have been several issues associated with
4594  *                 renegotiation or a poor understanding of its properties.
4595  *
4596  * \note           Server-side, enabling renegotiation also makes the server
4597  *                 susceptible to a resource DoS by a malicious client.
4598  *
4599  * \param conf    SSL configuration
4600  * \param renegotiation     Enable or disable (MBEDTLS_SSL_RENEGOTIATION_ENABLED or
4601  *                                             MBEDTLS_SSL_RENEGOTIATION_DISABLED)
4602  */
4603 void mbedtls_ssl_conf_renegotiation(mbedtls_ssl_config *conf, int renegotiation);
4604 #endif /* MBEDTLS_SSL_RENEGOTIATION */
4605 
4606 /**
4607  * \brief          Prevent or allow legacy renegotiation.
4608  *                 (Default: MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION)
4609  *
4610  *                 MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION allows connections to
4611  *                 be established even if the peer does not support
4612  *                 secure renegotiation, but does not allow renegotiation
4613  *                 to take place if not secure.
4614  *                 (Interoperable and secure option)
4615  *
4616  *                 MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION allows renegotiations
4617  *                 with non-upgraded peers. Allowing legacy renegotiation
4618  *                 makes the connection vulnerable to specific man in the
4619  *                 middle attacks. (See RFC 5746)
4620  *                 (Most interoperable and least secure option)
4621  *
4622  *                 MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE breaks off connections
4623  *                 if peer does not support secure renegotiation. Results
4624  *                 in interoperability issues with non-upgraded peers
4625  *                 that do not support renegotiation altogether.
4626  *                 (Most secure option, interoperability issues)
4627  *
4628  * \param conf     SSL configuration
4629  * \param allow_legacy  Prevent or allow (SSL_NO_LEGACY_RENEGOTIATION,
4630  *                                        SSL_ALLOW_LEGACY_RENEGOTIATION or
4631  *                                        MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE)
4632  */
4633 void mbedtls_ssl_conf_legacy_renegotiation(mbedtls_ssl_config *conf, int allow_legacy);
4634 
4635 #if defined(MBEDTLS_SSL_RENEGOTIATION)
4636 /**
4637  * \brief          Enforce renegotiation requests.
4638  *                 (Default: enforced, max_records = 16)
4639  *
4640  *                 When we request a renegotiation, the peer can comply or
4641  *                 ignore the request. This function allows us to decide
4642  *                 whether to enforce our renegotiation requests by closing
4643  *                 the connection if the peer doesn't comply.
4644  *
4645  *                 However, records could already be in transit from the peer
4646  *                 when the request is emitted. In order to increase
4647  *                 reliability, we can accept a number of records before the
4648  *                 expected handshake records.
4649  *
4650  *                 The optimal value is highly dependent on the specific usage
4651  *                 scenario.
4652  *
4653  * \note           With DTLS and server-initiated renegotiation, the
4654  *                 HelloRequest is retransmitted every time mbedtls_ssl_read() times
4655  *                 out or receives Application Data, until:
4656  *                 - max_records records have beens seen, if it is >= 0, or
4657  *                 - the number of retransmits that would happen during an
4658  *                 actual handshake has been reached.
4659  *                 Please remember the request might be lost a few times
4660  *                 if you consider setting max_records to a really low value.
4661  *
4662  * \warning        On client, the grace period can only happen during
4663  *                 mbedtls_ssl_read(), as opposed to mbedtls_ssl_write() and mbedtls_ssl_renegotiate()
4664  *                 which always behave as if max_record was 0. The reason is,
4665  *                 if we receive application data from the server, we need a
4666  *                 place to write it, which only happens during mbedtls_ssl_read().
4667  *
4668  * \param conf     SSL configuration
4669  * \param max_records Use MBEDTLS_SSL_RENEGOTIATION_NOT_ENFORCED if you don't want to
4670  *                 enforce renegotiation, or a non-negative value to enforce
4671  *                 it but allow for a grace period of max_records records.
4672  */
4673 void mbedtls_ssl_conf_renegotiation_enforced(mbedtls_ssl_config *conf, int max_records);
4674 
4675 /**
4676  * \brief          Set record counter threshold for periodic renegotiation.
4677  *                 (Default: 2^48 - 1)
4678  *
4679  *                 Renegotiation is automatically triggered when a record
4680  *                 counter (outgoing or incoming) crosses the defined
4681  *                 threshold. The default value is meant to prevent the
4682  *                 connection from being closed when the counter is about to
4683  *                 reached its maximal value (it is not allowed to wrap).
4684  *
4685  *                 Lower values can be used to enforce policies such as "keys
4686  *                 must be refreshed every N packets with cipher X".
4687  *
4688  *                 The renegotiation period can be disabled by setting
4689  *                 conf->disable_renegotiation to
4690  *                 MBEDTLS_SSL_RENEGOTIATION_DISABLED.
4691  *
4692  * \note           When the configured transport is
4693  *                 MBEDTLS_SSL_TRANSPORT_DATAGRAM the maximum renegotiation
4694  *                 period is 2^48 - 1, and for MBEDTLS_SSL_TRANSPORT_STREAM,
4695  *                 the maximum renegotiation period is 2^64 - 1.
4696  *
4697  * \param conf     SSL configuration
4698  * \param period   The threshold value: a big-endian 64-bit number.
4699  */
4700 void mbedtls_ssl_conf_renegotiation_period(mbedtls_ssl_config *conf,
4701                                            const unsigned char period[8]);
4702 #endif /* MBEDTLS_SSL_RENEGOTIATION */
4703 
4704 /**
4705  * \brief          Check if there is data already read from the
4706  *                 underlying transport but not yet processed.
4707  *
4708  * \param ssl      SSL context
4709  *
4710  * \return         0 if nothing's pending, 1 otherwise.
4711  *
4712  * \note           This is different in purpose and behaviour from
4713  *                 \c mbedtls_ssl_get_bytes_avail in that it considers
4714  *                 any kind of unprocessed data, not only unread
4715  *                 application data. If \c mbedtls_ssl_get_bytes
4716  *                 returns a non-zero value, this function will
4717  *                 also signal pending data, but the converse does
4718  *                 not hold. For example, in DTLS there might be
4719  *                 further records waiting to be processed from
4720  *                 the current underlying transport's datagram.
4721  *
4722  * \note           If this function returns 1 (data pending), this
4723  *                 does not imply that a subsequent call to
4724  *                 \c mbedtls_ssl_read will provide any data;
4725  *                 e.g., the unprocessed data might turn out
4726  *                 to be an alert or a handshake message.
4727  *
4728  * \note           This function is useful in the following situation:
4729  *                 If the SSL/TLS module successfully returns from an
4730  *                 operation - e.g. a handshake or an application record
4731  *                 read - and you're awaiting incoming data next, you
4732  *                 must not immediately idle on the underlying transport
4733  *                 to have data ready, but you need to check the value
4734  *                 of this function first. The reason is that the desired
4735  *                 data might already be read but not yet processed.
4736  *                 If, in contrast, a previous call to the SSL/TLS module
4737  *                 returned MBEDTLS_ERR_SSL_WANT_READ, it is not necessary
4738  *                 to call this function, as the latter error code entails
4739  *                 that all internal data has been processed.
4740  *
4741  */
4742 int mbedtls_ssl_check_pending(const mbedtls_ssl_context *ssl);
4743 
4744 /**
4745  * \brief          Return the number of application data bytes
4746  *                 remaining to be read from the current record.
4747  *
4748  * \param ssl      SSL context
4749  *
4750  * \return         How many bytes are available in the application
4751  *                 data record read buffer.
4752  *
4753  * \note           When working over a datagram transport, this is
4754  *                 useful to detect the current datagram's boundary
4755  *                 in case \c mbedtls_ssl_read has written the maximal
4756  *                 amount of data fitting into the input buffer.
4757  *
4758  */
4759 size_t mbedtls_ssl_get_bytes_avail(const mbedtls_ssl_context *ssl);
4760 
4761 /**
4762  * \brief          Return the result of the certificate verification
4763  *
4764  * \param ssl      The SSL context to use.
4765  *
4766  * \return         \c 0 if the certificate verification was successful.
4767  * \return         \c -1u if the result is not available. This may happen
4768  *                 e.g. if the handshake aborts early, or a verification
4769  *                 callback returned a fatal error.
4770  * \return         A bitwise combination of \c MBEDTLS_X509_BADCERT_XXX
4771  *                 and \c MBEDTLS_X509_BADCRL_XXX failure flags; see x509.h.
4772  */
4773 uint32_t mbedtls_ssl_get_verify_result(const mbedtls_ssl_context *ssl);
4774 
4775 /**
4776  * \brief          Return the id of the current ciphersuite
4777  *
4778  * \param ssl      SSL context
4779  *
4780  * \return         a ciphersuite id
4781  */
4782 int mbedtls_ssl_get_ciphersuite_id_from_ssl(const mbedtls_ssl_context *ssl);
4783 
4784 /**
4785  * \brief          Return the name of the current ciphersuite
4786  *
4787  * \param ssl      SSL context
4788  *
4789  * \return         a string containing the ciphersuite name
4790  */
4791 const char *mbedtls_ssl_get_ciphersuite(const mbedtls_ssl_context *ssl);
4792 
4793 
4794 /**
4795  * \brief          Return the (D)TLS protocol version negotiated in the
4796  *                 given connection.
4797  *
4798  * \note           If you call this function too early during the initial
4799  *                 handshake, before the two sides have agreed on a version,
4800  *                 this function returns #MBEDTLS_SSL_VERSION_UNKNOWN.
4801  *
4802  * \param ssl      The SSL context to query.
4803  * \return         The negotiated protocol version.
4804  */
mbedtls_ssl_get_version_number(const mbedtls_ssl_context * ssl)4805 static inline mbedtls_ssl_protocol_version mbedtls_ssl_get_version_number(
4806     const mbedtls_ssl_context *ssl)
4807 {
4808     return ssl->MBEDTLS_PRIVATE(tls_version);
4809 }
4810 
4811 /**
4812  * \brief          Return the current TLS version
4813  *
4814  * \param ssl      SSL context
4815  *
4816  * \return         a string containing the TLS version
4817  */
4818 const char *mbedtls_ssl_get_version(const mbedtls_ssl_context *ssl);
4819 
4820 /**
4821  * \brief          Return the (maximum) number of bytes added by the record
4822  *                 layer: header + encryption/MAC overhead (inc. padding)
4823  *
4824  * \param ssl      SSL context
4825  *
4826  * \return         Current maximum record expansion in bytes
4827  */
4828 int mbedtls_ssl_get_record_expansion(const mbedtls_ssl_context *ssl);
4829 
4830 /**
4831  * \brief          Return the current maximum outgoing record payload in bytes.
4832  *
4833  * \note           The logic to determine the maximum outgoing record payload is
4834  *                 version-specific. It takes into account various factors, such as
4835  *                 the mbedtls_config.h setting \c MBEDTLS_SSL_OUT_CONTENT_LEN, extensions
4836  *                 such as the max fragment length or record size limit extension if
4837  *                 used, and for DTLS the path MTU as configured and current
4838  *                 record expansion.
4839  *
4840  * \note           With DTLS, \c mbedtls_ssl_write() will return an error if
4841  *                 called with a larger length value.
4842  *                 With TLS, \c mbedtls_ssl_write() will fragment the input if
4843  *                 necessary and return the number of bytes written; it is up
4844  *                 to the caller to call \c mbedtls_ssl_write() again in
4845  *                 order to send the remaining bytes if any.
4846  *
4847  * \sa             mbedtls_ssl_get_max_out_record_payload()
4848  * \sa             mbedtls_ssl_get_record_expansion()
4849  *
4850  * \param ssl      SSL context
4851  *
4852  * \return         Current maximum payload for an outgoing record,
4853  *                 or a negative error code.
4854  */
4855 int mbedtls_ssl_get_max_out_record_payload(const mbedtls_ssl_context *ssl);
4856 
4857 /**
4858  * \brief          Return the current maximum incoming record payload in bytes.
4859  *
4860  * \note           The logic to determine the maximum incoming record payload is
4861  *                 version-specific. It takes into account various factors, such as
4862  *                 the mbedtls_config.h setting \c MBEDTLS_SSL_IN_CONTENT_LEN, extensions
4863  *                 such as the max fragment length extension or record size limit
4864  *                 extension if used, and the current record expansion.
4865  *
4866  * \sa             mbedtls_ssl_set_mtu()
4867  * \sa             mbedtls_ssl_get_max_in_record_payload()
4868  * \sa             mbedtls_ssl_get_record_expansion()
4869  *
4870  * \param ssl      SSL context
4871  *
4872  * \return         Current maximum payload for an incoming record,
4873  *                 or a negative error code.
4874  */
4875 int mbedtls_ssl_get_max_in_record_payload(const mbedtls_ssl_context *ssl);
4876 
4877 #if defined(MBEDTLS_X509_CRT_PARSE_C)
4878 /**
4879  * \brief          Return the peer certificate from the current connection.
4880  *
4881  * \param  ssl     The SSL context to use. This must be initialized and setup.
4882  *
4883  * \return         The current peer certificate, if available.
4884  *                 The returned certificate is owned by the SSL context and
4885  *                 is valid only until the next call to the SSL API.
4886  * \return         \c NULL if no peer certificate is available. This might
4887  *                 be because the chosen ciphersuite doesn't use CRTs
4888  *                 (PSK-based ciphersuites, for example), or because
4889  *                 #MBEDTLS_SSL_KEEP_PEER_CERTIFICATE has been disabled,
4890  *                 allowing the stack to free the peer's CRT to save memory.
4891  *
4892  * \note           For one-time inspection of the peer's certificate during
4893  *                 the handshake, consider registering an X.509 CRT verification
4894  *                 callback through mbedtls_ssl_conf_verify() instead of calling
4895  *                 this function. Using mbedtls_ssl_conf_verify() also comes at
4896  *                 the benefit of allowing you to influence the verification
4897  *                 process, for example by masking expected and tolerated
4898  *                 verification failures.
4899  *
4900  * \warning        You must not use the pointer returned by this function
4901  *                 after any further call to the SSL API, including
4902  *                 mbedtls_ssl_read() and mbedtls_ssl_write(); this is
4903  *                 because the pointer might change during renegotiation,
4904  *                 which happens transparently to the user.
4905  *                 If you want to use the certificate across API calls,
4906  *                 you must make a copy.
4907  */
4908 const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert(const mbedtls_ssl_context *ssl);
4909 #endif /* MBEDTLS_X509_CRT_PARSE_C */
4910 
4911 #if defined(MBEDTLS_SSL_CLI_C)
4912 /**
4913  * \brief          Export a session in order to resume it later.
4914  *
4915  * \param ssl      The SSL context representing the connection for which to
4916  *                 to export a session structure for later resumption.
4917  * \param session  The target structure in which to store the exported session.
4918  *                 This must have been initialized with mbedtls_ssl_session_init()
4919  *                 but otherwise be unused.
4920  *
4921  * \note           This function can handle a variety of mechanisms for session
4922  *                 resumption: For TLS 1.2, both session ID-based resumption and
4923  *                 ticket-based resumption will be considered. For TLS 1.3,
4924  *                 once implemented, sessions equate to tickets, and calling
4925  *                 this function multiple times will export the available
4926  *                 tickets one a time until no further tickets are available,
4927  *                 in which case MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE will
4928  *                 be returned.
4929  *
4930  * \note           Calling this function multiple times will only be useful
4931  *                 once TLS 1.3 is supported. For TLS 1.2 connections, this
4932  *                 function should be called at most once.
4933  *
4934  * \return         \c 0 if successful. In this case, \p session can be used for
4935  *                 session resumption by passing it to mbedtls_ssl_set_session(),
4936  *                 and serialized for storage via mbedtls_ssl_session_save().
4937  * \return         #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no further session
4938  *                 is available for export.
4939  *                 This error is a non-fatal, and has no observable effect on
4940  *                 the SSL context or the destination session.
4941  * \return         Another negative error code on other kinds of failure.
4942  *
4943  * \sa             mbedtls_ssl_set_session()
4944  * \sa             mbedtls_ssl_session_save()
4945  */
4946 int mbedtls_ssl_get_session(const mbedtls_ssl_context *ssl,
4947                             mbedtls_ssl_session *session);
4948 #endif /* MBEDTLS_SSL_CLI_C */
4949 
4950 /**
4951  * \brief          Perform the SSL handshake
4952  *
4953  * \param ssl      SSL context
4954  *
4955  * \return         \c 0 if successful.
4956  * \return         #MBEDTLS_ERR_SSL_WANT_READ or #MBEDTLS_ERR_SSL_WANT_WRITE
4957  *                 if the handshake is incomplete and waiting for data to
4958  *                 be available for reading from or writing to the underlying
4959  *                 transport - in this case you must call this function again
4960  *                 when the underlying transport is ready for the operation.
4961  * \return         #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if an asynchronous
4962  *                 operation is in progress (see
4963  *                 mbedtls_ssl_conf_async_private_cb()) - in this case you
4964  *                 must call this function again when the operation is ready.
4965  * \return         #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS if a cryptographic
4966  *                 operation is in progress (see mbedtls_ecp_set_max_ops()) -
4967  *                 in this case you must call this function again to complete
4968  *                 the handshake when you're done attending other tasks.
4969  * \return         #MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED if DTLS is in use
4970  *                 and the client did not demonstrate reachability yet - in
4971  *                 this case you must stop using the context (see below).
4972  * \return         #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA if early data, as
4973  *                 defined in RFC 8446 (TLS 1.3 specification), has been
4974  *                 received as part of the handshake. This is server specific
4975  *                 and may occur only if the early data feature has been
4976  *                 enabled on server (see mbedtls_ssl_conf_early_data()
4977  *                 documentation). You must call mbedtls_ssl_read_early_data()
4978  *                 to read the early data before resuming the handshake.
4979  * \return         Another SSL error code - in this case you must stop using
4980  *                 the context (see below).
4981  *
4982  * \warning        If this function returns something other than
4983  *                 \c 0,
4984  *                 #MBEDTLS_ERR_SSL_WANT_READ,
4985  *                 #MBEDTLS_ERR_SSL_WANT_WRITE,
4986  *                 #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS or
4987  *                 #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS or
4988  *                 #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA,
4989  *                 you must stop using the SSL context for reading or writing,
4990  *                 and either free it or call \c mbedtls_ssl_session_reset()
4991  *                 on it before re-using it for a new connection; the current
4992  *                 connection must be closed.
4993  *
4994  * \note           If DTLS is in use, then you may choose to handle
4995  *                 #MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED specially for logging
4996  *                 purposes, as it is an expected return value rather than an
4997  *                 actual error, but you still need to reset/free the context.
4998  *
4999  * \note           Remarks regarding event-driven DTLS:
5000  *                 If the function returns #MBEDTLS_ERR_SSL_WANT_READ, no datagram
5001  *                 from the underlying transport layer is currently being processed,
5002  *                 and it is safe to idle until the timer or the underlying transport
5003  *                 signal a new event. This is not true for a successful handshake,
5004  *                 in which case the datagram of the underlying transport that is
5005  *                 currently being processed might or might not contain further
5006  *                 DTLS records.
5007  *
5008  * \note           If the context is configured to allow TLS 1.3, or if
5009  *                 #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
5010  *                 subsystem must have been initialized by calling
5011  *                 psa_crypto_init() before calling this function.
5012  */
5013 int mbedtls_ssl_handshake(mbedtls_ssl_context *ssl);
5014 
5015 /**
5016  * \brief          After calling mbedtls_ssl_handshake() to start the SSL
5017  *                 handshake you can call this function to check whether the
5018  *                 handshake is over for a given SSL context. This function
5019  *                 should be also used to determine when to stop calling
5020  *                 mbedtls_handshake_step() for that context.
5021  *
5022  * \param ssl      SSL context
5023  *
5024  * \return         \c 1 if handshake is over, \c 0 if it is still ongoing.
5025  */
mbedtls_ssl_is_handshake_over(mbedtls_ssl_context * ssl)5026 static inline int mbedtls_ssl_is_handshake_over(mbedtls_ssl_context *ssl)
5027 {
5028     return ssl->MBEDTLS_PRIVATE(state) >= MBEDTLS_SSL_HANDSHAKE_OVER;
5029 }
5030 
5031 /**
5032  * \brief          Perform a single step of the SSL handshake
5033  *
5034  * \note           The state of the context (ssl->state) will be at
5035  *                 the next state after this function returns \c 0. Do not
5036  *                 call this function if mbedtls_ssl_is_handshake_over()
5037  *                 returns \c 1.
5038  *
5039  * \warning        Whilst in the past you may have used direct access to the
5040  *                 context state (ssl->state) in order to ascertain when to
5041  *                 stop calling this function and although you can still do
5042  *                 so with something like ssl->MBEDTLS_PRIVATE(state) or by
5043  *                 defining MBEDTLS_ALLOW_PRIVATE_ACCESS, this is now
5044  *                 considered deprecated and could be broken in any future
5045  *                 release. If you still find you have good reason for such
5046  *                 direct access, then please do contact the team to explain
5047  *                 this (raise an issue or post to the mailing list), so that
5048  *                 we can add a solution to your problem that will be
5049  *                 guaranteed to work in the future.
5050  *
5051  * \param ssl      SSL context
5052  *
5053  * \return         See mbedtls_ssl_handshake().
5054  *
5055  * \warning        If this function returns something other than \c 0,
5056  *                 #MBEDTLS_ERR_SSL_WANT_READ, #MBEDTLS_ERR_SSL_WANT_WRITE,
5057  *                 #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS,
5058  *                 #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS or
5059  *                 #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA, you must stop using
5060  *                 the SSL context for reading or writing, and either free it
5061  *                 or call \c mbedtls_ssl_session_reset() on it before
5062  *                 re-using it for a new connection; the current connection
5063  *                 must be closed.
5064  */
5065 int mbedtls_ssl_handshake_step(mbedtls_ssl_context *ssl);
5066 
5067 #if defined(MBEDTLS_SSL_RENEGOTIATION)
5068 /**
5069  * \brief          Initiate an SSL renegotiation on the running connection.
5070  *                 Client: perform the renegotiation right now.
5071  *                 Server: request renegotiation, which will be performed
5072  *                 during the next call to mbedtls_ssl_read() if honored by
5073  *                 client.
5074  *
5075  * \param ssl      SSL context
5076  *
5077  * \return         0 if successful, or any mbedtls_ssl_handshake() return
5078  *                 value except #MBEDTLS_ERR_SSL_CLIENT_RECONNECT that can't
5079  *                 happen during a renegotiation.
5080  *
5081  * \warning        If this function returns something other than \c 0,
5082  *                 #MBEDTLS_ERR_SSL_WANT_READ, #MBEDTLS_ERR_SSL_WANT_WRITE,
5083  *                 #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS or
5084  *                 #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS, you must stop using
5085  *                 the SSL context for reading or writing, and either free it
5086  *                 or call \c mbedtls_ssl_session_reset() on it before
5087  *                 re-using it for a new connection; the current connection
5088  *                 must be closed.
5089  *
5090  */
5091 int mbedtls_ssl_renegotiate(mbedtls_ssl_context *ssl);
5092 #endif /* MBEDTLS_SSL_RENEGOTIATION */
5093 
5094 /**
5095  * \brief          Read at most 'len' application data bytes
5096  *
5097  * \param ssl      SSL context
5098  * \param buf      buffer that will hold the data
5099  * \param len      maximum number of bytes to read
5100  *
5101  * \return         The (positive) number of bytes read if successful.
5102  * \return         \c 0 if the read end of the underlying transport was closed
5103  *                 without sending a CloseNotify beforehand, which might happen
5104  *                 because of various reasons (internal error of an underlying
5105  *                 stack, non-conformant peer not sending a CloseNotify and
5106  *                 such) - in this case you must stop using the context
5107  *                 (see below).
5108  * \return         #MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY if the underlying
5109  *                 transport is still functional, but the peer has
5110  *                 acknowledged to not send anything anymore.
5111  * \return         #MBEDTLS_ERR_SSL_WANT_READ or #MBEDTLS_ERR_SSL_WANT_WRITE
5112  *                 if the handshake is incomplete and waiting for data to
5113  *                 be available for reading from or writing to the underlying
5114  *                 transport - in this case you must call this function again
5115  *                 when the underlying transport is ready for the operation.
5116  * \return         #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if an asynchronous
5117  *                 operation is in progress (see
5118  *                 mbedtls_ssl_conf_async_private_cb()) - in this case you
5119  *                 must call this function again when the operation is ready.
5120  * \return         #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS if a cryptographic
5121  *                 operation is in progress (see mbedtls_ecp_set_max_ops()) -
5122  *                 in this case you must call this function again to complete
5123  *                 the handshake when you're done attending other tasks.
5124  * \return         #MBEDTLS_ERR_SSL_CLIENT_RECONNECT if we're at the server
5125  *                 side of a DTLS connection and the client is initiating a
5126  *                 new connection using the same source port. See below.
5127  * \return         #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA if early data, as
5128  *                 defined in RFC 8446 (TLS 1.3 specification), has been
5129  *                 received as part of the handshake. This is server specific
5130  *                 and may occur only if the early data feature has been
5131  *                 enabled on server (see mbedtls_ssl_conf_early_data()
5132  *                 documentation). You must call mbedtls_ssl_read_early_data()
5133  *                 to read the early data before resuming the handshake.
5134  * \return         Another SSL error code - in this case you must stop using
5135  *                 the context (see below).
5136  *
5137  * \warning        If this function returns something other than
5138  *                 a positive value,
5139  *                 #MBEDTLS_ERR_SSL_WANT_READ,
5140  *                 #MBEDTLS_ERR_SSL_WANT_WRITE,
5141  *                 #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS,
5142  *                 #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS,
5143  *                 #MBEDTLS_ERR_SSL_CLIENT_RECONNECT or
5144  *                 #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA,
5145  *                 you must stop using the SSL context for reading or writing,
5146  *                 and either free it or call \c mbedtls_ssl_session_reset()
5147  *                 on it before re-using it for a new connection; the current
5148  *                 connection must be closed.
5149  *
5150  * \note           When this function returns #MBEDTLS_ERR_SSL_CLIENT_RECONNECT
5151  *                 (which can only happen server-side), it means that a client
5152  *                 is initiating a new connection using the same source port.
5153  *                 You can either treat that as a connection close and wait
5154  *                 for the client to resend a ClientHello, or directly
5155  *                 continue with \c mbedtls_ssl_handshake() with the same
5156  *                 context (as it has been reset internally). Either way, you
5157  *                 must make sure this is seen by the application as a new
5158  *                 connection: application state, if any, should be reset, and
5159  *                 most importantly the identity of the client must be checked
5160  *                 again. WARNING: not validating the identity of the client
5161  *                 again, or not transmitting the new identity to the
5162  *                 application layer, would allow authentication bypass!
5163  *
5164  * \note           Remarks regarding event-driven DTLS:
5165  *                 - If the function returns #MBEDTLS_ERR_SSL_WANT_READ, no datagram
5166  *                   from the underlying transport layer is currently being processed,
5167  *                   and it is safe to idle until the timer or the underlying transport
5168  *                   signal a new event.
5169  *                 - This function may return MBEDTLS_ERR_SSL_WANT_READ even if data was
5170  *                   initially available on the underlying transport, as this data may have
5171  *                   been only e.g. duplicated messages or a renegotiation request.
5172  *                   Therefore, you must be prepared to receive MBEDTLS_ERR_SSL_WANT_READ even
5173  *                   when reacting to an incoming-data event from the underlying transport.
5174  *                 - On success, the datagram of the underlying transport that is currently
5175  *                   being processed may contain further DTLS records. You should call
5176  *                   \c mbedtls_ssl_check_pending to check for remaining records.
5177  *
5178  */
5179 int mbedtls_ssl_read(mbedtls_ssl_context *ssl, unsigned char *buf, size_t len);
5180 
5181 /**
5182  * \brief          Try to write exactly 'len' application data bytes
5183  *
5184  * \warning        This function will do partial writes in some cases. If the
5185  *                 return value is non-negative but less than length, the
5186  *                 function must be called again with updated arguments:
5187  *                 buf + ret, len - ret (if ret is the return value) until
5188  *                 it returns a value equal to the last 'len' argument.
5189  *
5190  * \param ssl      SSL context
5191  * \param buf      buffer holding the data
5192  * \param len      how many bytes must be written
5193  *
5194  * \return         The (non-negative) number of bytes actually written if
5195  *                 successful (may be less than \p len).
5196  * \return         #MBEDTLS_ERR_SSL_WANT_READ or #MBEDTLS_ERR_SSL_WANT_WRITE
5197  *                 if the handshake is incomplete and waiting for data to
5198  *                 be available for reading from or writing to the underlying
5199  *                 transport - in this case you must call this function again
5200  *                 when the underlying transport is ready for the operation.
5201  * \return         #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if an asynchronous
5202  *                 operation is in progress (see
5203  *                 mbedtls_ssl_conf_async_private_cb()) - in this case you
5204  *                 must call this function again when the operation is ready.
5205  * \return         #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS if a cryptographic
5206  *                 operation is in progress (see mbedtls_ecp_set_max_ops()) -
5207  *                 in this case you must call this function again to complete
5208  *                 the handshake when you're done attending other tasks.
5209  * \return         #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA if early data, as
5210  *                 defined in RFC 8446 (TLS 1.3 specification), has been
5211  *                 received as part of the handshake. This is server specific
5212  *                 and may occur only if the early data feature has been
5213  *                 enabled on server (see mbedtls_ssl_conf_early_data()
5214  *                 documentation). You must call mbedtls_ssl_read_early_data()
5215  *                 to read the early data before resuming the handshake.
5216  * \return         Another SSL error code - in this case you must stop using
5217  *                 the context (see below).
5218  *
5219  * \warning        If this function returns something other than
5220  *                 a non-negative value,
5221  *                 #MBEDTLS_ERR_SSL_WANT_READ,
5222  *                 #MBEDTLS_ERR_SSL_WANT_WRITE,
5223  *                 #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS,
5224  *                 #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS or
5225  *                 #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA,
5226  *                 you must stop using the SSL context for reading or writing,
5227  *                 and either free it or call \c mbedtls_ssl_session_reset()
5228  *                 on it before re-using it for a new connection; the current
5229  *                 connection must be closed.
5230  *
5231  * \note           When this function returns #MBEDTLS_ERR_SSL_WANT_WRITE/READ,
5232  *                 it must be called later with the *same* arguments,
5233  *                 until it returns a value greater than or equal to 0. When
5234  *                 the function returns #MBEDTLS_ERR_SSL_WANT_WRITE there may be
5235  *                 some partial data in the output buffer, however this is not
5236  *                 yet sent.
5237  *
5238  * \note           If the requested length is greater than the maximum
5239  *                 fragment length (either the built-in limit or the one set
5240  *                 or negotiated with the peer), then:
5241  *                 - with TLS, less bytes than requested are written.
5242  *                 - with DTLS, MBEDTLS_ERR_SSL_BAD_INPUT_DATA is returned.
5243  *                 \c mbedtls_ssl_get_max_out_record_payload() may be used to
5244  *                 query the active maximum fragment length.
5245  *
5246  * \note           Attempting to write 0 bytes will result in an empty TLS
5247  *                 application record being sent.
5248  */
5249 int mbedtls_ssl_write(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len);
5250 
5251 /**
5252  * \brief           Send an alert message
5253  *
5254  * \param ssl       SSL context
5255  * \param level     The alert level of the message
5256  *                  (MBEDTLS_SSL_ALERT_LEVEL_WARNING or MBEDTLS_SSL_ALERT_LEVEL_FATAL)
5257  * \param message   The alert message (SSL_ALERT_MSG_*)
5258  *
5259  * \return          0 if successful, or a specific SSL error code.
5260  *
5261  * \note           If this function returns something other than 0 or
5262  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, you must stop using
5263  *                 the SSL context for reading or writing, and either free it or
5264  *                 call \c mbedtls_ssl_session_reset() on it before re-using it
5265  *                 for a new connection; the current connection must be closed.
5266  */
5267 int mbedtls_ssl_send_alert_message(mbedtls_ssl_context *ssl,
5268                                    unsigned char level,
5269                                    unsigned char message);
5270 /**
5271  * \brief          Notify the peer that the connection is being closed
5272  *
5273  * \param ssl      SSL context
5274  *
5275  * \return          0 if successful, or a specific SSL error code.
5276  *
5277  * \note           If this function returns something other than 0 or
5278  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, you must stop using
5279  *                 the SSL context for reading or writing, and either free it or
5280  *                 call \c mbedtls_ssl_session_reset() on it before re-using it
5281  *                 for a new connection; the current connection must be closed.
5282  */
5283 int mbedtls_ssl_close_notify(mbedtls_ssl_context *ssl);
5284 
5285 #if defined(MBEDTLS_SSL_EARLY_DATA)
5286 
5287 #if defined(MBEDTLS_SSL_SRV_C)
5288 /**
5289  * \brief          Read at most 'len' bytes of early data
5290  *
5291  * \note           This API is server specific.
5292  *
5293  * \warning        Early data is defined in the TLS 1.3 specification, RFC 8446.
5294  *                 IMPORTANT NOTE from section 2.3 of the specification:
5295  *
5296  *                 The security properties for 0-RTT data are weaker than
5297  *                 those for other kinds of TLS data. Specifically:
5298  *                 - This data is not forward secret, as it is encrypted
5299  *                   solely under keys derived using the offered PSK.
5300  *                 - There are no guarantees of non-replay between connections.
5301  *                   Protection against replay for ordinary TLS 1.3 1-RTT data
5302  *                   is provided via the server's Random value, but 0-RTT data
5303  *                   does not depend on the ServerHello and therefore has
5304  *                   weaker guarantees. This is especially relevant if the
5305  *                   data is authenticated either with TLS client
5306  *                   authentication or inside the application protocol. The
5307  *                   same warnings apply to any use of the
5308  *                   early_exporter_master_secret.
5309  *
5310  * \warning        Mbed TLS does not implement any of the anti-replay defenses
5311  *                 defined in section 8 of the TLS 1.3 specification:
5312  *                 single-use of tickets or ClientHello recording within a
5313  *                 given time window.
5314  *
5315  * \note           This function is used in conjunction with
5316  *                 mbedtls_ssl_handshake(), mbedtls_ssl_handshake_step(),
5317  *                 mbedtls_ssl_read() and mbedtls_ssl_write() to read early
5318  *                 data when these functions return
5319  *                 #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA.
5320  *
5321  * \param ssl      SSL context, it must have been initialized and set up.
5322  * \param buf      buffer that will hold the data
5323  * \param len      maximum number of bytes to read
5324  *
5325  * \return         The (positive) number of bytes read if successful.
5326  * \return         #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if input data is invalid.
5327  * \return         #MBEDTLS_ERR_SSL_CANNOT_READ_EARLY_DATA if it is not
5328  *                 possible to read early data for the SSL context \p ssl. Note
5329  *                 that this function is intended to be called for an SSL
5330  *                 context \p ssl only after a call to mbedtls_ssl_handshake(),
5331  *                 mbedtls_ssl_handshake_step(), mbedtls_ssl_read() or
5332  *                 mbedtls_ssl_write() for \p ssl that has returned
5333  *                 #MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA.
5334  */
5335 int mbedtls_ssl_read_early_data(mbedtls_ssl_context *ssl,
5336                                 unsigned char *buf, size_t len);
5337 #endif /* MBEDTLS_SSL_SRV_C */
5338 
5339 #if defined(MBEDTLS_SSL_CLI_C)
5340 /**
5341  * \brief          Try to write exactly 'len' application data bytes while
5342  *                 performing the handshake (early data).
5343  *
5344  * \warning        Early data is defined in the TLS 1.3 specification, RFC 8446.
5345  *                 IMPORTANT NOTE from section 2.3 of the specification:
5346  *
5347  *                 The security properties for 0-RTT data are weaker than
5348  *                 those for other kinds of TLS data. Specifically:
5349  *                 - This data is not forward secret, as it is encrypted
5350  *                   solely under keys derived using the offered PSK.
5351  *                 - There are no guarantees of non-replay between connections.
5352  *                   Protection against replay for ordinary TLS 1.3 1-RTT data
5353  *                   is provided via the server's Random value, but 0-RTT data
5354  *                   does not depend on the ServerHello and therefore has
5355  *                   weaker guarantees. This is especially relevant if the
5356  *                   data is authenticated either with TLS client
5357  *                   authentication or inside the application protocol. The
5358  *                   same warnings apply to any use of the
5359  *                   early_exporter_master_secret.
5360  *
5361  * \note           This function behaves mainly as mbedtls_ssl_write(). The
5362  *                 specification of mbedtls_ssl_write() relevant to TLS 1.3
5363  *                 (thus not the parts specific to (D)TLS1.2) applies to this
5364  *                 function and the present documentation is mainly restricted
5365  *                 to the differences with mbedtls_ssl_write(). One noticeable
5366  *                 difference though is that mbedtls_ssl_write() aims to
5367  *                 complete the handshake before to write application data
5368  *                 while mbedtls_ssl_write_early() aims to drive the handshake
5369  *                 just past the point where it is not possible to send early
5370  *                 data anymore.
5371  *
5372  * \param ssl      SSL context
5373  * \param buf      buffer holding the data
5374  * \param len      how many bytes must be written
5375  *
5376  * \return         The (non-negative) number of bytes actually written if
5377  *                 successful (may be less than \p len).
5378  *
5379  * \return         One additional specific error code compared to
5380  *                 mbedtls_ssl_write():
5381  *                 #MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA.
5382  *
5383  *                 #MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA is returned when it
5384  *                 is not possible to write early data for the SSL context
5385  *                 \p ssl.
5386  *
5387  *                 It may have been possible and it is not possible
5388  *                 anymore because the client received the server Finished
5389  *                 message, the server rejected early data or the maximum
5390  *                 number of allowed early data for the PSK in use has been
5391  *                 reached.
5392  *
5393  *                 It may never have been possible and will never be possible
5394  *                 for the SSL context \p ssl because the use of early data
5395  *                 is disabled for that context or more generally the context
5396  *                 is not suitably configured to enable early data or the first
5397  *                 call to the function was done while the handshake was
5398  *                 already completed.
5399  *
5400  *                 It is not possible to write early data for the SSL context
5401  *                 \p ssl and any subsequent call to this API will return this
5402  *                 error code. But this does not preclude for using it with
5403  *                 mbedtls_ssl_write(), mbedtls_ssl_read() or
5404  *                 mbedtls_ssl_handshake() and the handshake can be
5405  *                 completed by calling one of these APIs.
5406  *
5407  * \note           This function may write early data only if the SSL context
5408  *                 has been configured for the handshake with a PSK for which
5409  *                 early data is allowed.
5410  *
5411  * \note           To maximize the number of early data that can be written in
5412  *                 the course of the handshake, it is expected that this
5413  *                 function starts the handshake for the SSL context \p ssl.
5414  *                 But this is not mandatory.
5415  *
5416  * \note           This function does not provide any information on whether
5417  *                 the server has accepted or will accept early data or not.
5418  *                 When it returns a positive value, it just means that it
5419  *                 has written early data to the server. To know whether the
5420  *                 server has accepted early data or not, you should call
5421  *                 mbedtls_ssl_get_early_data_status() with the handshake
5422  *                 completed.
5423  */
5424 int mbedtls_ssl_write_early_data(mbedtls_ssl_context *ssl,
5425                                  const unsigned char *buf, size_t len);
5426 
5427 /**
5428  * \brief Get the status of the negotiation of the use of early data.
5429  *
5430  * \param ssl      The SSL context to query
5431  *
5432  * \return         #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if this function is called
5433  *                 from the server-side.
5434  *
5435  * \return         #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if this function is called
5436  *                 prior to completion of the handshake.
5437  *
5438  * \return         #MBEDTLS_SSL_EARLY_DATA_STATUS_NOT_INDICATED if the client
5439  *                 has not indicated the use of early data to the server.
5440  *
5441  * \return         #MBEDTLS_SSL_EARLY_DATA_STATUS_ACCEPTED if the client has
5442  *                 indicated the use of early data and the server has accepted
5443  *                 it.
5444  *
5445  * \return         #MBEDTLS_SSL_EARLY_DATA_STATUS_REJECTED if the client has
5446  *                 indicated the use of early data but the server has rejected
5447  *                 it. In this situation, the client may want to re-send the
5448  *                 early data it may have tried to send by calling
5449  *                 mbedtls_ssl_write_early_data() as ordinary post-handshake
5450  *                 application data by calling mbedtls_ssl_write().
5451  *
5452  */
5453 int mbedtls_ssl_get_early_data_status(mbedtls_ssl_context *ssl);
5454 #endif /* MBEDTLS_SSL_CLI_C */
5455 
5456 #endif /* MBEDTLS_SSL_EARLY_DATA */
5457 
5458 /**
5459  * \brief          Free referenced items in an SSL context and clear memory
5460  *
5461  * \param ssl      SSL context
5462  */
5463 void mbedtls_ssl_free(mbedtls_ssl_context *ssl);
5464 
5465 #if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
5466 /**
5467  * \brief          Save an active connection as serialized data in a buffer.
5468  *                 This allows the freeing or re-using of the SSL context
5469  *                 while still picking up the connection later in a way that
5470  *                 it entirely transparent to the peer.
5471  *
5472  * \see            mbedtls_ssl_context_load()
5473  *
5474  * \note           The serialized data only contains the data that is
5475  *                 necessary to resume the connection: negotiated protocol
5476  *                 options, session identifier, keys, etc.
5477  *                 Loading a saved SSL context does not restore settings and
5478  *                 state related to how the application accesses the context,
5479  *                 such as configured callback functions, user data, pending
5480  *                 incoming or outgoing data, etc.
5481  *
5482  * \note           This feature is currently only available under certain
5483  *                 conditions, see the documentation of the return value
5484  *                 #MBEDTLS_ERR_SSL_BAD_INPUT_DATA for details.
5485  *
5486  * \note           When this function succeeds, it calls
5487  *                 mbedtls_ssl_session_reset() on \p ssl which as a result is
5488  *                 no longer associated with the connection that has been
5489  *                 serialized. This avoids creating copies of the connection
5490  *                 state. You're then free to either re-use the context
5491  *                 structure for a different connection, or call
5492  *                 mbedtls_ssl_free() on it. See the documentation of
5493  *                 mbedtls_ssl_session_reset() for more details.
5494  *
5495  * \param ssl      The SSL context to save. On success, it is no longer
5496  *                 associated with the connection that has been serialized.
5497  * \param buf      The buffer to write the serialized data to. It must be a
5498  *                 writeable buffer of at least \p buf_len bytes, or may be \c
5499  *                 NULL if \p buf_len is \c 0.
5500  * \param buf_len  The number of bytes available for writing in \p buf.
5501  * \param olen     The size in bytes of the data that has been or would have
5502  *                 been written. It must point to a valid \c size_t.
5503  *
5504  * \note           \p olen is updated to the correct value regardless of
5505  *                 whether \p buf_len was large enough. This makes it possible
5506  *                 to determine the necessary size by calling this function
5507  *                 with \p buf set to \c NULL and \p buf_len to \c 0. However,
5508  *                 the value of \p olen is only guaranteed to be correct when
5509  *                 the function returns #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL or
5510  *                 \c 0. If the return value is different, then the value of
5511  *                 \p olen is undefined.
5512  *
5513  * \return         \c 0 if successful.
5514  * \return         #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL if \p buf is too small.
5515  * \return         #MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed
5516  *                 while resetting the context.
5517  * \return         #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if a handshake is in
5518  *                 progress, or there is pending data for reading or sending,
5519  *                 or the connection does not use DTLS 1.2 with an AEAD
5520  *                 ciphersuite, or renegotiation is enabled.
5521  */
5522 int mbedtls_ssl_context_save(mbedtls_ssl_context *ssl,
5523                              unsigned char *buf,
5524                              size_t buf_len,
5525                              size_t *olen);
5526 
5527 /**
5528  * \brief          Load serialized connection data to an SSL context.
5529  *
5530  * \see            mbedtls_ssl_context_save()
5531  *
5532  * \warning        The same serialized data must never be loaded into more
5533  *                 that one context. In order to ensure that, after
5534  *                 successfully loading serialized data to an SSL context, you
5535  *                 should immediately destroy or invalidate all copies of the
5536  *                 serialized data that was loaded. Loading the same data in
5537  *                 more than one context would cause severe security failures
5538  *                 including but not limited to loss of confidentiality.
5539  *
5540  * \note           Before calling this function, the SSL context must be
5541  *                 prepared in one of the two following ways. The first way is
5542  *                 to take a context freshly initialised with
5543  *                 mbedtls_ssl_init() and call mbedtls_ssl_setup() on it with
5544  *                 the same ::mbedtls_ssl_config structure that was used in
5545  *                 the original connection. The second way is to
5546  *                 call mbedtls_ssl_session_reset() on a context that was
5547  *                 previously prepared as above but used in the meantime.
5548  *                 Either way, you must not use the context to perform a
5549  *                 handshake between calling mbedtls_ssl_setup() or
5550  *                 mbedtls_ssl_session_reset() and calling this function. You
5551  *                 may however call other setter functions in that time frame
5552  *                 as indicated in the note below.
5553  *
5554  * \note           Before or after calling this function successfully, you
5555  *                 also need to configure some connection-specific callbacks
5556  *                 and settings before you can use the connection again
5557  *                 (unless they were already set before calling
5558  *                 mbedtls_ssl_session_reset() and the values are suitable for
5559  *                 the present connection). Specifically, you want to call
5560  *                 at least mbedtls_ssl_set_bio(),
5561  *                 mbedtls_ssl_set_timer_cb(), and
5562  *                 mbedtls_ssl_set_user_data_n() or
5563  *                 mbedtls_ssl_set_user_data_p() if they were set originally.
5564  *                 All other SSL setter functions
5565  *                 are not necessary to call, either because they're only used
5566  *                 in handshakes, or because the setting is already saved. You
5567  *                 might choose to call them anyway, for example in order to
5568  *                 share code between the cases of establishing a new
5569  *                 connection and the case of loading an already-established
5570  *                 connection.
5571  *
5572  * \note           If you have new information about the path MTU, you want to
5573  *                 call mbedtls_ssl_set_mtu() after calling this function, as
5574  *                 otherwise this function would overwrite your
5575  *                 newly-configured value with the value that was active when
5576  *                 the context was saved.
5577  *
5578  * \note           When this function returns an error code, it calls
5579  *                 mbedtls_ssl_free() on \p ssl. In this case, you need to
5580  *                 prepare the context with the usual sequence starting with a
5581  *                 call to mbedtls_ssl_init() if you want to use it again.
5582  *
5583  * \param ssl      The SSL context structure to be populated. It must have
5584  *                 been prepared as described in the note above.
5585  * \param buf      The buffer holding the serialized connection data. It must
5586  *                 be a readable buffer of at least \p len bytes.
5587  * \param len      The size of the serialized data in bytes.
5588  *
5589  * \return         \c 0 if successful.
5590  * \return         #MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed.
5591  * \return         #MBEDTLS_ERR_SSL_VERSION_MISMATCH if the serialized data
5592  *                 comes from a different Mbed TLS version or build.
5593  * \return         #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if input data is invalid.
5594  */
5595 int mbedtls_ssl_context_load(mbedtls_ssl_context *ssl,
5596                              const unsigned char *buf,
5597                              size_t len);
5598 #endif /* MBEDTLS_SSL_CONTEXT_SERIALIZATION */
5599 
5600 /**
5601  * \brief          Initialize an SSL configuration context
5602  *                 Just makes the context ready for
5603  *                 mbedtls_ssl_config_defaults() or mbedtls_ssl_config_free().
5604  *
5605  * \note           You need to call mbedtls_ssl_config_defaults() unless you
5606  *                 manually set all of the relevant fields yourself.
5607  *
5608  * \param conf     SSL configuration context
5609  */
5610 void mbedtls_ssl_config_init(mbedtls_ssl_config *conf);
5611 
5612 /**
5613  * \brief          Load reasonable default SSL configuration values.
5614  *                 (You need to call mbedtls_ssl_config_init() first.)
5615  *
5616  * \param conf     SSL configuration context
5617  * \param endpoint MBEDTLS_SSL_IS_CLIENT or MBEDTLS_SSL_IS_SERVER
5618  * \param transport MBEDTLS_SSL_TRANSPORT_STREAM for TLS, or
5619  *                  MBEDTLS_SSL_TRANSPORT_DATAGRAM for DTLS
5620  * \param preset   a MBEDTLS_SSL_PRESET_XXX value
5621  *
5622  * \note           See \c mbedtls_ssl_conf_transport() for notes on DTLS.
5623  *
5624  * \return         0 if successful, or
5625  *                 MBEDTLS_ERR_XXX_ALLOC_FAILED on memory allocation error.
5626  */
5627 int mbedtls_ssl_config_defaults(mbedtls_ssl_config *conf,
5628                                 int endpoint, int transport, int preset);
5629 
5630 /**
5631  * \brief          Free an SSL configuration context
5632  *
5633  * \param conf     SSL configuration context
5634  */
5635 void mbedtls_ssl_config_free(mbedtls_ssl_config *conf);
5636 
5637 /**
5638  * \brief          Initialize SSL session structure
5639  *
5640  * \param session  SSL session
5641  */
5642 void mbedtls_ssl_session_init(mbedtls_ssl_session *session);
5643 
5644 /**
5645  * \brief          Free referenced items in an SSL session including the
5646  *                 peer certificate and clear memory
5647  *
5648  * \note           A session object can be freed even if the SSL context
5649  *                 that was used to retrieve the session is still in use.
5650  *
5651  * \param session  SSL session
5652  */
5653 void mbedtls_ssl_session_free(mbedtls_ssl_session *session);
5654 
5655 /**
5656  * \brief          TLS-PRF function for key derivation.
5657  *
5658  * \param prf      The tls_prf type function type to be used.
5659  * \param secret   Secret for the key derivation function.
5660  * \param slen     Length of the secret.
5661  * \param label    String label for the key derivation function,
5662  *                 terminated with null character.
5663  * \param random   Random bytes.
5664  * \param rlen     Length of the random bytes buffer.
5665  * \param dstbuf   The buffer holding the derived key.
5666  * \param dlen     Length of the output buffer.
5667  *
5668  * \return         0 on success. An SSL specific error on failure.
5669  */
5670 int  mbedtls_ssl_tls_prf(const mbedtls_tls_prf_types prf,
5671                          const unsigned char *secret, size_t slen,
5672                          const char *label,
5673                          const unsigned char *random, size_t rlen,
5674                          unsigned char *dstbuf, size_t dlen);
5675 
5676 #ifdef __cplusplus
5677 }
5678 #endif
5679 
5680 #endif /* ssl.h */
5681