1 /**
2 * \file pk.h
3 *
4 * \brief Public Key abstraction layer
5 */
6 /*
7 * Copyright The Mbed TLS Contributors
8 * SPDX-License-Identifier: Apache-2.0
9 *
10 * Licensed under the Apache License, Version 2.0 (the "License"); you may
11 * not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
18 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
21 */
22
23 #ifndef MBEDTLS_PK_H
24 #define MBEDTLS_PK_H
25 #include "mbedtls/private_access.h"
26
27 #include "mbedtls/build_info.h"
28
29 #include "mbedtls/md.h"
30
31 #if defined(MBEDTLS_RSA_C)
32 #include "mbedtls/rsa.h"
33 #endif
34
35 #if defined(MBEDTLS_ECP_C)
36 #include "mbedtls/ecp.h"
37 #endif
38
39 #if defined(MBEDTLS_ECDSA_C)
40 #include "mbedtls/ecdsa.h"
41 #endif
42
43 #if defined(MBEDTLS_USE_PSA_CRYPTO)
44 #include "psa/crypto.h"
45 #endif
46
47 /** Memory allocation failed. */
48 #define MBEDTLS_ERR_PK_ALLOC_FAILED -0x3F80
49 /** Type mismatch, eg attempt to encrypt with an ECDSA key */
50 #define MBEDTLS_ERR_PK_TYPE_MISMATCH -0x3F00
51 /** Bad input parameters to function. */
52 #define MBEDTLS_ERR_PK_BAD_INPUT_DATA -0x3E80
53 /** Read/write of file failed. */
54 #define MBEDTLS_ERR_PK_FILE_IO_ERROR -0x3E00
55 /** Unsupported key version */
56 #define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80
57 /** Invalid key tag or value. */
58 #define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT -0x3D00
59 /** Key algorithm is unsupported (only RSA and EC are supported). */
60 #define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG -0x3C80
61 /** Private key password can't be empty. */
62 #define MBEDTLS_ERR_PK_PASSWORD_REQUIRED -0x3C00
63 /** Given private key password does not allow for correct decryption. */
64 #define MBEDTLS_ERR_PK_PASSWORD_MISMATCH -0x3B80
65 /** The pubkey tag or value is invalid (only RSA and EC are supported). */
66 #define MBEDTLS_ERR_PK_INVALID_PUBKEY -0x3B00
67 /** The algorithm tag or value is invalid. */
68 #define MBEDTLS_ERR_PK_INVALID_ALG -0x3A80
69 /** Elliptic curve is unsupported (only NIST curves are supported). */
70 #define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00
71 /** Unavailable feature, e.g. RSA disabled for RSA key. */
72 #define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980
73 /** The buffer contains a valid signature followed by more data. */
74 #define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH -0x3900
75 /** The output buffer is too small. */
76 #define MBEDTLS_ERR_PK_BUFFER_TOO_SMALL -0x3880
77
78 #ifdef __cplusplus
79 extern "C" {
80 #endif
81
82 /**
83 * \brief Public key types
84 */
85 typedef enum {
86 MBEDTLS_PK_NONE=0,
87 MBEDTLS_PK_RSA,
88 MBEDTLS_PK_ECKEY,
89 MBEDTLS_PK_ECKEY_DH,
90 MBEDTLS_PK_ECDSA,
91 MBEDTLS_PK_RSA_ALT,
92 MBEDTLS_PK_RSASSA_PSS,
93 MBEDTLS_PK_OPAQUE,
94 } mbedtls_pk_type_t;
95
96 /**
97 * \brief Options for RSASSA-PSS signature verification.
98 * See \c mbedtls_rsa_rsassa_pss_verify_ext()
99 */
100 typedef struct mbedtls_pk_rsassa_pss_options {
101 /** The digest to use for MGF1 in PSS.
102 *
103 * \note When #MBEDTLS_USE_PSA_CRYPTO is enabled and #MBEDTLS_RSA_C is
104 * disabled, this must be equal to the \c md_alg argument passed
105 * to mbedtls_pk_verify_ext(). In a future version of the library,
106 * this constraint may apply whenever #MBEDTLS_USE_PSA_CRYPTO is
107 * enabled regardless of the status of #MBEDTLS_RSA_C.
108 */
109 mbedtls_md_type_t mgf1_hash_id;
110
111 /** The expected length of the salt, in bytes. This may be
112 * #MBEDTLS_RSA_SALT_LEN_ANY to accept any salt length.
113 *
114 * \note When #MBEDTLS_USE_PSA_CRYPTO is enabled, only
115 * #MBEDTLS_RSA_SALT_LEN_ANY is valid. Any other value may be
116 * ignored (allowing any salt length).
117 */
118 int expected_salt_len;
119
120 } mbedtls_pk_rsassa_pss_options;
121
122 /**
123 * \brief Maximum size of a signature made by mbedtls_pk_sign().
124 */
125 /* We need to set MBEDTLS_PK_SIGNATURE_MAX_SIZE to the maximum signature
126 * size among the supported signature types. Do it by starting at 0,
127 * then incrementally increasing to be large enough for each supported
128 * signature mechanism.
129 *
130 * The resulting value can be 0, for example if MBEDTLS_ECDH_C is enabled
131 * (which allows the pk module to be included) but neither MBEDTLS_ECDSA_C
132 * nor MBEDTLS_RSA_C nor any opaque signature mechanism (PSA or RSA_ALT).
133 */
134 #define MBEDTLS_PK_SIGNATURE_MAX_SIZE 0
135
136 #if (defined(MBEDTLS_RSA_C) || defined(MBEDTLS_PK_RSA_ALT_SUPPORT)) && \
137 MBEDTLS_MPI_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE
138 /* For RSA, the signature can be as large as the bignum module allows.
139 * For RSA_ALT, the signature size is not necessarily tied to what the
140 * bignum module can do, but in the absence of any specific setting,
141 * we use that (rsa_alt_sign_wrap in library/pk_wrap.h will check). */
142 #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
143 #define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE
144 #endif
145
146 #if defined(MBEDTLS_ECDSA_C) && \
147 MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_PK_SIGNATURE_MAX_SIZE
148 /* For ECDSA, the ecdsa module exports a constant for the maximum
149 * signature size. */
150 #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
151 #define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN
152 #endif
153
154 #if defined(MBEDTLS_USE_PSA_CRYPTO)
155 #if PSA_SIGNATURE_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE
156 /* PSA_SIGNATURE_MAX_SIZE is the maximum size of a signature made
157 * through the PSA API in the PSA representation. */
158 #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
159 #define MBEDTLS_PK_SIGNATURE_MAX_SIZE PSA_SIGNATURE_MAX_SIZE
160 #endif
161
162 #if PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11 > MBEDTLS_PK_SIGNATURE_MAX_SIZE
163 /* The Mbed TLS representation is different for ECDSA signatures:
164 * PSA uses the raw concatenation of r and s,
165 * whereas Mbed TLS uses the ASN.1 representation (SEQUENCE of two INTEGERs).
166 * Add the overhead of ASN.1: up to (1+2) + 2 * (1+2+1) for the
167 * types, lengths (represented by up to 2 bytes), and potential leading
168 * zeros of the INTEGERs and the SEQUENCE. */
169 #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
170 #define MBEDTLS_PK_SIGNATURE_MAX_SIZE (PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11)
171 #endif
172 #endif /* defined(MBEDTLS_USE_PSA_CRYPTO) */
173
174 /**
175 * \brief The following defines are meant to list ECDSA capabilities of the
176 * PK module in a general way (without any reference to how this
177 * is achieved, which can be either through PSA driver or
178 * MBEDTLS_ECDSA_C)
179 */
180 #if !defined(MBEDTLS_USE_PSA_CRYPTO)
181 #if defined(MBEDTLS_ECDSA_C)
182 #define MBEDTLS_PK_CAN_ECDSA_SIGN
183 #define MBEDTLS_PK_CAN_ECDSA_VERIFY
184 #endif
185 #else /* MBEDTLS_USE_PSA_CRYPTO */
186 #if defined(PSA_WANT_ALG_ECDSA)
187 #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR)
188 #define MBEDTLS_PK_CAN_ECDSA_SIGN
189 #endif
190 #if defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY)
191 #define MBEDTLS_PK_CAN_ECDSA_VERIFY
192 #endif
193 #endif /* PSA_WANT_ALG_ECDSA */
194 #endif /* MBEDTLS_USE_PSA_CRYPTO */
195
196 #if defined(MBEDTLS_PK_CAN_ECDSA_VERIFY) || defined(MBEDTLS_PK_CAN_ECDSA_SIGN)
197 #define MBEDTLS_PK_CAN_ECDSA_SOME
198 #endif
199
200 /**
201 * \brief Types for interfacing with the debug module
202 */
203 typedef enum {
204 MBEDTLS_PK_DEBUG_NONE = 0,
205 MBEDTLS_PK_DEBUG_MPI,
206 MBEDTLS_PK_DEBUG_ECP,
207 } mbedtls_pk_debug_type;
208
209 /**
210 * \brief Item to send to the debug module
211 */
212 typedef struct mbedtls_pk_debug_item {
213 mbedtls_pk_debug_type MBEDTLS_PRIVATE(type);
214 const char *MBEDTLS_PRIVATE(name);
215 void *MBEDTLS_PRIVATE(value);
216 } mbedtls_pk_debug_item;
217
218 /** Maximum number of item send for debugging, plus 1 */
219 #define MBEDTLS_PK_DEBUG_MAX_ITEMS 3
220
221 /**
222 * \brief Public key information and operations
223 *
224 * \note The library does not support custom pk info structures,
225 * only built-in structures returned by
226 * mbedtls_cipher_info_from_type().
227 */
228 typedef struct mbedtls_pk_info_t mbedtls_pk_info_t;
229
230 /**
231 * \brief Public key container
232 */
233 typedef struct mbedtls_pk_context {
234 const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info); /**< Public key information */
235 void *MBEDTLS_PRIVATE(pk_ctx); /**< Underlying public key context */
236 } mbedtls_pk_context;
237
238 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
239 /**
240 * \brief Context for resuming operations
241 */
242 typedef struct {
243 const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info); /**< Public key information */
244 void *MBEDTLS_PRIVATE(rs_ctx); /**< Underlying restart context */
245 } mbedtls_pk_restart_ctx;
246 #else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
247 /* Now we can declare functions that take a pointer to that */
248 typedef void mbedtls_pk_restart_ctx;
249 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
250
251 #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
252 /**
253 * \brief Types for RSA-alt abstraction
254 */
255 typedef int (*mbedtls_pk_rsa_alt_decrypt_func)(void *ctx, size_t *olen,
256 const unsigned char *input, unsigned char *output,
257 size_t output_max_len);
258 typedef int (*mbedtls_pk_rsa_alt_sign_func)(void *ctx,
259 int (*f_rng)(void *, unsigned char *, size_t),
260 void *p_rng,
261 mbedtls_md_type_t md_alg, unsigned int hashlen,
262 const unsigned char *hash, unsigned char *sig);
263 typedef size_t (*mbedtls_pk_rsa_alt_key_len_func)(void *ctx);
264 #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
265
266 /**
267 * \brief Return information associated with the given PK type
268 *
269 * \param pk_type PK type to search for.
270 *
271 * \return The PK info associated with the type or NULL if not found.
272 */
273 const mbedtls_pk_info_t *mbedtls_pk_info_from_type(mbedtls_pk_type_t pk_type);
274
275 /**
276 * \brief Initialize a #mbedtls_pk_context (as NONE).
277 *
278 * \param ctx The context to initialize.
279 * This must not be \c NULL.
280 */
281 void mbedtls_pk_init(mbedtls_pk_context *ctx);
282
283 /**
284 * \brief Free the components of a #mbedtls_pk_context.
285 *
286 * \param ctx The context to clear. It must have been initialized.
287 * If this is \c NULL, this function does nothing.
288 *
289 * \note For contexts that have been set up with
290 * mbedtls_pk_setup_opaque(), this does not free the underlying
291 * PSA key and you still need to call psa_destroy_key()
292 * independently if you want to destroy that key.
293 */
294 void mbedtls_pk_free(mbedtls_pk_context *ctx);
295
296 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
297 /**
298 * \brief Initialize a restart context
299 *
300 * \param ctx The context to initialize.
301 * This must not be \c NULL.
302 */
303 void mbedtls_pk_restart_init(mbedtls_pk_restart_ctx *ctx);
304
305 /**
306 * \brief Free the components of a restart context
307 *
308 * \param ctx The context to clear. It must have been initialized.
309 * If this is \c NULL, this function does nothing.
310 */
311 void mbedtls_pk_restart_free(mbedtls_pk_restart_ctx *ctx);
312 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
313
314 /**
315 * \brief Initialize a PK context with the information given
316 * and allocates the type-specific PK subcontext.
317 *
318 * \param ctx Context to initialize. It must not have been set
319 * up yet (type #MBEDTLS_PK_NONE).
320 * \param info Information to use
321 *
322 * \return 0 on success,
323 * MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input,
324 * MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
325 *
326 * \note For contexts holding an RSA-alt key, use
327 * \c mbedtls_pk_setup_rsa_alt() instead.
328 */
329 int mbedtls_pk_setup(mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info);
330
331 #if defined(MBEDTLS_USE_PSA_CRYPTO)
332 /**
333 * \brief Initialize a PK context to wrap a PSA key.
334 *
335 * \note This function replaces mbedtls_pk_setup() for contexts
336 * that wrap a (possibly opaque) PSA key instead of
337 * storing and manipulating the key material directly.
338 *
339 * \param ctx The context to initialize. It must be empty (type NONE).
340 * \param key The PSA key to wrap, which must hold an ECC or RSA key
341 * pair (see notes below).
342 *
343 * \note The wrapped key must remain valid as long as the
344 * wrapping PK context is in use, that is at least between
345 * the point this function is called and the point
346 * mbedtls_pk_free() is called on this context. The wrapped
347 * key might then be independently used or destroyed.
348 *
349 * \note This function is currently only available for ECC or RSA
350 * key pairs (that is, keys containing private key material).
351 * Support for other key types may be added later.
352 *
353 * \return \c 0 on success.
354 * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input
355 * (context already used, invalid key identifier).
356 * \return #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the key is not an
357 * ECC key pair.
358 * \return #MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
359 */
360 int mbedtls_pk_setup_opaque(mbedtls_pk_context *ctx,
361 const mbedtls_svc_key_id_t key);
362 #endif /* MBEDTLS_USE_PSA_CRYPTO */
363
364 #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
365 /**
366 * \brief Initialize an RSA-alt context
367 *
368 * \param ctx Context to initialize. It must not have been set
369 * up yet (type #MBEDTLS_PK_NONE).
370 * \param key RSA key pointer
371 * \param decrypt_func Decryption function
372 * \param sign_func Signing function
373 * \param key_len_func Function returning key length in bytes
374 *
375 * \return 0 on success, or MBEDTLS_ERR_PK_BAD_INPUT_DATA if the
376 * context wasn't already initialized as RSA_ALT.
377 *
378 * \note This function replaces \c mbedtls_pk_setup() for RSA-alt.
379 */
380 int mbedtls_pk_setup_rsa_alt(mbedtls_pk_context *ctx, void *key,
381 mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
382 mbedtls_pk_rsa_alt_sign_func sign_func,
383 mbedtls_pk_rsa_alt_key_len_func key_len_func);
384 #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
385
386 /**
387 * \brief Get the size in bits of the underlying key
388 *
389 * \param ctx The context to query. It must have been initialized.
390 *
391 * \return Key size in bits, or 0 on error
392 */
393 size_t mbedtls_pk_get_bitlen(const mbedtls_pk_context *ctx);
394
395 /**
396 * \brief Get the length in bytes of the underlying key
397 *
398 * \param ctx The context to query. It must have been initialized.
399 *
400 * \return Key length in bytes, or 0 on error
401 */
mbedtls_pk_get_len(const mbedtls_pk_context * ctx)402 static inline size_t mbedtls_pk_get_len(const mbedtls_pk_context *ctx)
403 {
404 return (mbedtls_pk_get_bitlen(ctx) + 7) / 8;
405 }
406
407 /**
408 * \brief Tell if a context can do the operation given by type
409 *
410 * \param ctx The context to query. It must have been initialized.
411 * \param type The desired type.
412 *
413 * \return 1 if the context can do operations on the given type.
414 * \return 0 if the context cannot do the operations on the given
415 * type. This is always the case for a context that has
416 * been initialized but not set up, or that has been
417 * cleared with mbedtls_pk_free().
418 */
419 int mbedtls_pk_can_do(const mbedtls_pk_context *ctx, mbedtls_pk_type_t type);
420
421 #if defined(MBEDTLS_USE_PSA_CRYPTO)
422 /**
423 * \brief Tell if context can do the operation given by PSA algorithm
424 *
425 * \param ctx The context to query. It must have been initialized.
426 * \param alg PSA algorithm to check against, the following are allowed:
427 * PSA_ALG_RSA_PKCS1V15_SIGN(hash),
428 * PSA_ALG_RSA_PSS(hash),
429 * PSA_ALG_RSA_PKCS1V15_CRYPT,
430 * PSA_ALG_ECDSA(hash),
431 * PSA_ALG_ECDH, where hash is a specific hash.
432 * \param usage PSA usage flag to check against, must be composed of:
433 * PSA_KEY_USAGE_SIGN_HASH
434 * PSA_KEY_USAGE_DECRYPT
435 * PSA_KEY_USAGE_DERIVE.
436 * Context key must match all passed usage flags.
437 *
438 * \warning Since the set of allowed algorithms and usage flags may be
439 * expanded in the future, the return value \c 0 should not
440 * be taken in account for non-allowed algorithms and usage
441 * flags.
442 *
443 * \return 1 if the context can do operations on the given type.
444 * \return 0 if the context cannot do the operations on the given
445 * type, for non-allowed algorithms and usage flags, or
446 * for a context that has been initialized but not set up
447 * or that has been cleared with mbedtls_pk_free().
448 */
449 int mbedtls_pk_can_do_ext(const mbedtls_pk_context *ctx, psa_algorithm_t alg,
450 psa_key_usage_t usage);
451 #endif /* MBEDTLS_USE_PSA_CRYPTO */
452
453 /**
454 * \brief Verify signature (including padding if relevant).
455 *
456 * \param ctx The PK context to use. It must have been set up.
457 * \param md_alg Hash algorithm used.
458 * This can be #MBEDTLS_MD_NONE if the signature algorithm
459 * does not rely on a hash algorithm (non-deterministic
460 * ECDSA, RSA PKCS#1 v1.5).
461 * For PKCS#1 v1.5, if \p md_alg is #MBEDTLS_MD_NONE, then
462 * \p hash is the DigestInfo structure used by RFC 8017
463 * §9.2 steps 3–6. If \p md_alg is a valid hash
464 * algorithm then \p hash is the digest itself, and this
465 * function calculates the DigestInfo encoding internally.
466 * \param hash Hash of the message to sign
467 * \param hash_len Hash length
468 * \param sig Signature to verify
469 * \param sig_len Signature length
470 *
471 * \return 0 on success (signature is valid),
472 * #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid
473 * signature in sig but its length is less than \p siglen,
474 * or a specific error code.
475 *
476 * \note For RSA keys, the default padding type is PKCS#1 v1.5.
477 * Use \c mbedtls_pk_verify_ext( MBEDTLS_PK_RSASSA_PSS, ... )
478 * to verify RSASSA_PSS signatures.
479 */
480 int mbedtls_pk_verify(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
481 const unsigned char *hash, size_t hash_len,
482 const unsigned char *sig, size_t sig_len);
483
484 /**
485 * \brief Restartable version of \c mbedtls_pk_verify()
486 *
487 * \note Performs the same job as \c mbedtls_pk_verify(), but can
488 * return early and restart according to the limit set with
489 * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC
490 * operations. For RSA, same as \c mbedtls_pk_verify().
491 *
492 * \param ctx The PK context to use. It must have been set up.
493 * \param md_alg Hash algorithm used (see notes)
494 * \param hash Hash of the message to sign
495 * \param hash_len Hash length or 0 (see notes)
496 * \param sig Signature to verify
497 * \param sig_len Signature length
498 * \param rs_ctx Restart context (NULL to disable restart)
499 *
500 * \return See \c mbedtls_pk_verify(), or
501 * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
502 * operations was reached: see \c mbedtls_ecp_set_max_ops().
503 */
504 int mbedtls_pk_verify_restartable(mbedtls_pk_context *ctx,
505 mbedtls_md_type_t md_alg,
506 const unsigned char *hash, size_t hash_len,
507 const unsigned char *sig, size_t sig_len,
508 mbedtls_pk_restart_ctx *rs_ctx);
509
510 /**
511 * \brief Verify signature, with options.
512 * (Includes verification of the padding depending on type.)
513 *
514 * \param type Signature type (inc. possible padding type) to verify
515 * \param options Pointer to type-specific options, or NULL
516 * \param ctx The PK context to use. It must have been set up.
517 * \param md_alg Hash algorithm used (see notes)
518 * \param hash Hash of the message to sign
519 * \param hash_len Hash length or 0 (see notes)
520 * \param sig Signature to verify
521 * \param sig_len Signature length
522 *
523 * \return 0 on success (signature is valid),
524 * #MBEDTLS_ERR_PK_TYPE_MISMATCH if the PK context can't be
525 * used for this type of signatures,
526 * #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid
527 * signature in sig but its length is less than \p siglen,
528 * or a specific error code.
529 *
530 * \note If hash_len is 0, then the length associated with md_alg
531 * is used instead, or an error returned if it is invalid.
532 *
533 * \note md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0
534 *
535 * \note If type is MBEDTLS_PK_RSASSA_PSS, then options must point
536 * to a mbedtls_pk_rsassa_pss_options structure,
537 * otherwise it must be NULL. Note that if
538 * #MBEDTLS_USE_PSA_CRYPTO is defined, the salt length is not
539 * verified as PSA_ALG_RSA_PSS_ANY_SALT is used.
540 */
541 int mbedtls_pk_verify_ext(mbedtls_pk_type_t type, const void *options,
542 mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
543 const unsigned char *hash, size_t hash_len,
544 const unsigned char *sig, size_t sig_len);
545
546 /**
547 * \brief Make signature, including padding if relevant.
548 *
549 * \param ctx The PK context to use. It must have been set up
550 * with a private key.
551 * \param md_alg Hash algorithm used (see notes)
552 * \param hash Hash of the message to sign
553 * \param hash_len Hash length
554 * \param sig Place to write the signature.
555 * It must have enough room for the signature.
556 * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
557 * You may use a smaller buffer if it is large enough
558 * given the key type.
559 * \param sig_size The size of the \p sig buffer in bytes.
560 * \param sig_len On successful return,
561 * the number of bytes written to \p sig.
562 * \param f_rng RNG function, must not be \c NULL.
563 * \param p_rng RNG parameter
564 *
565 * \return 0 on success, or a specific error code.
566 *
567 * \note For RSA keys, the default padding type is PKCS#1 v1.5.
568 * There is no interface in the PK module to make RSASSA-PSS
569 * signatures yet.
570 *
571 * \note For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0.
572 * For ECDSA, md_alg may never be MBEDTLS_MD_NONE.
573 */
574 int mbedtls_pk_sign(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
575 const unsigned char *hash, size_t hash_len,
576 unsigned char *sig, size_t sig_size, size_t *sig_len,
577 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
578
579 #if defined(MBEDTLS_PSA_CRYPTO_C)
580 /**
581 * \brief Make signature given a signature type.
582 *
583 * \param pk_type Signature type.
584 * \param ctx The PK context to use. It must have been set up
585 * with a private key.
586 * \param md_alg Hash algorithm used (see notes)
587 * \param hash Hash of the message to sign
588 * \param hash_len Hash length
589 * \param sig Place to write the signature.
590 * It must have enough room for the signature.
591 * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
592 * You may use a smaller buffer if it is large enough
593 * given the key type.
594 * \param sig_size The size of the \p sig buffer in bytes.
595 * \param sig_len On successful return,
596 * the number of bytes written to \p sig.
597 * \param f_rng RNG function, must not be \c NULL.
598 * \param p_rng RNG parameter
599 *
600 * \return 0 on success, or a specific error code.
601 *
602 * \note When \p pk_type is #MBEDTLS_PK_RSASSA_PSS,
603 * see #PSA_ALG_RSA_PSS for a description of PSS options used.
604 *
605 * \note For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0.
606 * For ECDSA, md_alg may never be MBEDTLS_MD_NONE.
607 *
608 */
609 int mbedtls_pk_sign_ext(mbedtls_pk_type_t pk_type,
610 mbedtls_pk_context *ctx,
611 mbedtls_md_type_t md_alg,
612 const unsigned char *hash, size_t hash_len,
613 unsigned char *sig, size_t sig_size, size_t *sig_len,
614 int (*f_rng)(void *, unsigned char *, size_t),
615 void *p_rng);
616 #endif /* MBEDTLS_PSA_CRYPTO_C */
617
618 /**
619 * \brief Restartable version of \c mbedtls_pk_sign()
620 *
621 * \note Performs the same job as \c mbedtls_pk_sign(), but can
622 * return early and restart according to the limit set with
623 * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC
624 * operations. For RSA, same as \c mbedtls_pk_sign().
625 *
626 * \param ctx The PK context to use. It must have been set up
627 * with a private key.
628 * \param md_alg Hash algorithm used (see notes for mbedtls_pk_sign())
629 * \param hash Hash of the message to sign
630 * \param hash_len Hash length
631 * \param sig Place to write the signature.
632 * It must have enough room for the signature.
633 * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
634 * You may use a smaller buffer if it is large enough
635 * given the key type.
636 * \param sig_size The size of the \p sig buffer in bytes.
637 * \param sig_len On successful return,
638 * the number of bytes written to \p sig.
639 * \param f_rng RNG function, must not be \c NULL.
640 * \param p_rng RNG parameter
641 * \param rs_ctx Restart context (NULL to disable restart)
642 *
643 * \return See \c mbedtls_pk_sign().
644 * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
645 * operations was reached: see \c mbedtls_ecp_set_max_ops().
646 */
647 int mbedtls_pk_sign_restartable(mbedtls_pk_context *ctx,
648 mbedtls_md_type_t md_alg,
649 const unsigned char *hash, size_t hash_len,
650 unsigned char *sig, size_t sig_size, size_t *sig_len,
651 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
652 mbedtls_pk_restart_ctx *rs_ctx);
653
654 /**
655 * \brief Decrypt message (including padding if relevant).
656 *
657 * \param ctx The PK context to use. It must have been set up
658 * with a private key.
659 * \param input Input to decrypt
660 * \param ilen Input size
661 * \param output Decrypted output
662 * \param olen Decrypted message length
663 * \param osize Size of the output buffer
664 * \param f_rng RNG function, must not be \c NULL.
665 * \param p_rng RNG parameter
666 *
667 * \note For RSA keys, the default padding type is PKCS#1 v1.5.
668 *
669 * \return 0 on success, or a specific error code.
670 */
671 int mbedtls_pk_decrypt(mbedtls_pk_context *ctx,
672 const unsigned char *input, size_t ilen,
673 unsigned char *output, size_t *olen, size_t osize,
674 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
675
676 /**
677 * \brief Encrypt message (including padding if relevant).
678 *
679 * \param ctx The PK context to use. It must have been set up.
680 * \param input Message to encrypt
681 * \param ilen Message size
682 * \param output Encrypted output
683 * \param olen Encrypted output length
684 * \param osize Size of the output buffer
685 * \param f_rng RNG function, must not be \c NULL.
686 * \param p_rng RNG parameter
687 *
688 * \note \p f_rng is used for padding generation.
689 *
690 * \note For RSA keys, the default padding type is PKCS#1 v1.5.
691 *
692 * \return 0 on success, or a specific error code.
693 */
694 int mbedtls_pk_encrypt(mbedtls_pk_context *ctx,
695 const unsigned char *input, size_t ilen,
696 unsigned char *output, size_t *olen, size_t osize,
697 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
698
699 /**
700 * \brief Check if a public-private pair of keys matches.
701 *
702 * \param pub Context holding a public key.
703 * \param prv Context holding a private (and public) key.
704 * \param f_rng RNG function, must not be \c NULL.
705 * \param p_rng RNG parameter
706 *
707 * \return \c 0 on success (keys were checked and match each other).
708 * \return #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the keys could not
709 * be checked - in that case they may or may not match.
710 * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA if a context is invalid.
711 * \return Another non-zero value if the keys do not match.
712 */
713 int mbedtls_pk_check_pair(const mbedtls_pk_context *pub,
714 const mbedtls_pk_context *prv,
715 int (*f_rng)(void *, unsigned char *, size_t),
716 void *p_rng);
717
718 /**
719 * \brief Export debug information
720 *
721 * \param ctx The PK context to use. It must have been initialized.
722 * \param items Place to write debug items
723 *
724 * \return 0 on success or MBEDTLS_ERR_PK_BAD_INPUT_DATA
725 */
726 int mbedtls_pk_debug(const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items);
727
728 /**
729 * \brief Access the type name
730 *
731 * \param ctx The PK context to use. It must have been initialized.
732 *
733 * \return Type name on success, or "invalid PK"
734 */
735 const char *mbedtls_pk_get_name(const mbedtls_pk_context *ctx);
736
737 /**
738 * \brief Get the key type
739 *
740 * \param ctx The PK context to use. It must have been initialized.
741 *
742 * \return Type on success.
743 * \return #MBEDTLS_PK_NONE for a context that has not been set up.
744 */
745 mbedtls_pk_type_t mbedtls_pk_get_type(const mbedtls_pk_context *ctx);
746
747 #if defined(MBEDTLS_RSA_C)
748 /**
749 * Quick access to an RSA context inside a PK context.
750 *
751 * \warning This function can only be used when the type of the context, as
752 * returned by mbedtls_pk_get_type(), is #MBEDTLS_PK_RSA.
753 * Ensuring that is the caller's responsibility.
754 * Alternatively, you can check whether this function returns NULL.
755 *
756 * \return The internal RSA context held by the PK context, or NULL.
757 */
mbedtls_pk_rsa(const mbedtls_pk_context pk)758 static inline mbedtls_rsa_context *mbedtls_pk_rsa(const mbedtls_pk_context pk)
759 {
760 switch (mbedtls_pk_get_type(&pk)) {
761 case MBEDTLS_PK_RSA:
762 return (mbedtls_rsa_context *) (pk).MBEDTLS_PRIVATE(pk_ctx);
763 default:
764 return NULL;
765 }
766 }
767 #endif /* MBEDTLS_RSA_C */
768
769 #if defined(MBEDTLS_ECP_C)
770 /**
771 * Quick access to an EC context inside a PK context.
772 *
773 * \warning This function can only be used when the type of the context, as
774 * returned by mbedtls_pk_get_type(), is #MBEDTLS_PK_ECKEY,
775 * #MBEDTLS_PK_ECKEY_DH, or #MBEDTLS_PK_ECDSA.
776 * Ensuring that is the caller's responsibility.
777 * Alternatively, you can check whether this function returns NULL.
778 *
779 * \return The internal EC context held by the PK context, or NULL.
780 */
mbedtls_pk_ec(const mbedtls_pk_context pk)781 static inline mbedtls_ecp_keypair *mbedtls_pk_ec(const mbedtls_pk_context pk)
782 {
783 switch (mbedtls_pk_get_type(&pk)) {
784 case MBEDTLS_PK_ECKEY:
785 case MBEDTLS_PK_ECKEY_DH:
786 case MBEDTLS_PK_ECDSA:
787 return (mbedtls_ecp_keypair *) (pk).MBEDTLS_PRIVATE(pk_ctx);
788 default:
789 return NULL;
790 }
791 }
792 #endif /* MBEDTLS_ECP_C */
793
794 #if defined(MBEDTLS_PK_PARSE_C)
795 /** \ingroup pk_module */
796 /**
797 * \brief Parse a private key in PEM or DER format
798 *
799 * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
800 * subsystem must have been initialized by calling
801 * psa_crypto_init() before calling this function.
802 *
803 * \param ctx The PK context to fill. It must have been initialized
804 * but not set up.
805 * \param key Input buffer to parse.
806 * The buffer must contain the input exactly, with no
807 * extra trailing material. For PEM, the buffer must
808 * contain a null-terminated string.
809 * \param keylen Size of \b key in bytes.
810 * For PEM data, this includes the terminating null byte,
811 * so \p keylen must be equal to `strlen(key) + 1`.
812 * \param pwd Optional password for decryption.
813 * Pass \c NULL if expecting a non-encrypted key.
814 * Pass a string of \p pwdlen bytes if expecting an encrypted
815 * key; a non-encrypted key will also be accepted.
816 * The empty password is not supported.
817 * \param pwdlen Size of the password in bytes.
818 * Ignored if \p pwd is \c NULL.
819 * \param f_rng RNG function, must not be \c NULL. Used for blinding.
820 * \param p_rng RNG parameter
821 *
822 * \note On entry, ctx must be empty, either freshly initialised
823 * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
824 * specific key type, check the result with mbedtls_pk_can_do().
825 *
826 * \note The key is also checked for correctness.
827 *
828 * \return 0 if successful, or a specific PK or PEM error code
829 */
830 int mbedtls_pk_parse_key(mbedtls_pk_context *ctx,
831 const unsigned char *key, size_t keylen,
832 const unsigned char *pwd, size_t pwdlen,
833 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
834
835 /** \ingroup pk_module */
836 /**
837 * \brief Parse a public key in PEM or DER format
838 *
839 * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
840 * subsystem must have been initialized by calling
841 * psa_crypto_init() before calling this function.
842 *
843 * \param ctx The PK context to fill. It must have been initialized
844 * but not set up.
845 * \param key Input buffer to parse.
846 * The buffer must contain the input exactly, with no
847 * extra trailing material. For PEM, the buffer must
848 * contain a null-terminated string.
849 * \param keylen Size of \b key in bytes.
850 * For PEM data, this includes the terminating null byte,
851 * so \p keylen must be equal to `strlen(key) + 1`.
852 *
853 * \note On entry, ctx must be empty, either freshly initialised
854 * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
855 * specific key type, check the result with mbedtls_pk_can_do().
856 *
857 * \note For compressed points, see #MBEDTLS_ECP_PF_COMPRESSED for
858 * limitations.
859 *
860 * \note The key is also checked for correctness.
861 *
862 * \return 0 if successful, or a specific PK or PEM error code
863 */
864 int mbedtls_pk_parse_public_key(mbedtls_pk_context *ctx,
865 const unsigned char *key, size_t keylen);
866
867 #if defined(MBEDTLS_FS_IO)
868 /** \ingroup pk_module */
869 /**
870 * \brief Load and parse a private key
871 *
872 * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
873 * subsystem must have been initialized by calling
874 * psa_crypto_init() before calling this function.
875 *
876 * \param ctx The PK context to fill. It must have been initialized
877 * but not set up.
878 * \param path filename to read the private key from
879 * \param password Optional password to decrypt the file.
880 * Pass \c NULL if expecting a non-encrypted key.
881 * Pass a null-terminated string if expecting an encrypted
882 * key; a non-encrypted key will also be accepted.
883 * The empty password is not supported.
884 * \param f_rng RNG function, must not be \c NULL. Used for blinding.
885 * \param p_rng RNG parameter
886 *
887 * \note On entry, ctx must be empty, either freshly initialised
888 * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
889 * specific key type, check the result with mbedtls_pk_can_do().
890 *
891 * \note The key is also checked for correctness.
892 *
893 * \return 0 if successful, or a specific PK or PEM error code
894 */
895 int mbedtls_pk_parse_keyfile(mbedtls_pk_context *ctx,
896 const char *path, const char *password,
897 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
898
899 /** \ingroup pk_module */
900 /**
901 * \brief Load and parse a public key
902 *
903 * \param ctx The PK context to fill. It must have been initialized
904 * but not set up.
905 * \param path filename to read the public key from
906 *
907 * \note On entry, ctx must be empty, either freshly initialised
908 * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If
909 * you need a specific key type, check the result with
910 * mbedtls_pk_can_do().
911 *
912 * \note The key is also checked for correctness.
913 *
914 * \return 0 if successful, or a specific PK or PEM error code
915 */
916 int mbedtls_pk_parse_public_keyfile(mbedtls_pk_context *ctx, const char *path);
917 #endif /* MBEDTLS_FS_IO */
918 #endif /* MBEDTLS_PK_PARSE_C */
919
920 #if defined(MBEDTLS_PK_WRITE_C)
921 /**
922 * \brief Write a private key to a PKCS#1 or SEC1 DER structure
923 * Note: data is written at the end of the buffer! Use the
924 * return value to determine where you should start
925 * using the buffer
926 *
927 * \param ctx PK context which must contain a valid private key.
928 * \param buf buffer to write to
929 * \param size size of the buffer
930 *
931 * \return length of data written if successful, or a specific
932 * error code
933 */
934 int mbedtls_pk_write_key_der(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);
935
936 /**
937 * \brief Write a public key to a SubjectPublicKeyInfo DER structure
938 * Note: data is written at the end of the buffer! Use the
939 * return value to determine where you should start
940 * using the buffer
941 *
942 * \param ctx PK context which must contain a valid public or private key.
943 * \param buf buffer to write to
944 * \param size size of the buffer
945 *
946 * \return length of data written if successful, or a specific
947 * error code
948 */
949 int mbedtls_pk_write_pubkey_der(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);
950
951 #if defined(MBEDTLS_PEM_WRITE_C)
952 /**
953 * \brief Write a public key to a PEM string
954 *
955 * \param ctx PK context which must contain a valid public or private key.
956 * \param buf Buffer to write to. The output includes a
957 * terminating null byte.
958 * \param size Size of the buffer in bytes.
959 *
960 * \return 0 if successful, or a specific error code
961 */
962 int mbedtls_pk_write_pubkey_pem(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);
963
964 /**
965 * \brief Write a private key to a PKCS#1 or SEC1 PEM string
966 *
967 * \param ctx PK context which must contain a valid private key.
968 * \param buf Buffer to write to. The output includes a
969 * terminating null byte.
970 * \param size Size of the buffer in bytes.
971 *
972 * \return 0 if successful, or a specific error code
973 */
974 int mbedtls_pk_write_key_pem(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size);
975 #endif /* MBEDTLS_PEM_WRITE_C */
976 #endif /* MBEDTLS_PK_WRITE_C */
977
978 /*
979 * WARNING: Low-level functions. You probably do not want to use these unless
980 * you are certain you do ;)
981 */
982
983 #if defined(MBEDTLS_PK_PARSE_C)
984 /**
985 * \brief Parse a SubjectPublicKeyInfo DER structure
986 *
987 * \param p the position in the ASN.1 data
988 * \param end end of the buffer
989 * \param pk The PK context to fill. It must have been initialized
990 * but not set up.
991 *
992 * \return 0 if successful, or a specific PK error code
993 */
994 int mbedtls_pk_parse_subpubkey(unsigned char **p, const unsigned char *end,
995 mbedtls_pk_context *pk);
996 #endif /* MBEDTLS_PK_PARSE_C */
997
998 #if defined(MBEDTLS_PK_WRITE_C)
999 /**
1000 * \brief Write a subjectPublicKey to ASN.1 data
1001 * Note: function works backwards in data buffer
1002 *
1003 * \param p reference to current position pointer
1004 * \param start start of the buffer (for bounds-checking)
1005 * \param key PK context which must contain a valid public or private key.
1006 *
1007 * \return the length written or a negative error code
1008 */
1009 int mbedtls_pk_write_pubkey(unsigned char **p, unsigned char *start,
1010 const mbedtls_pk_context *key);
1011 #endif /* MBEDTLS_PK_WRITE_C */
1012
1013 /*
1014 * Internal module functions. You probably do not want to use these unless you
1015 * know you do.
1016 */
1017 #if defined(MBEDTLS_FS_IO)
1018 int mbedtls_pk_load_file(const char *path, unsigned char **buf, size_t *n);
1019 #endif
1020
1021 #if defined(MBEDTLS_USE_PSA_CRYPTO)
1022 /**
1023 * \brief Turn an EC or RSA key into an opaque one.
1024 *
1025 * \warning This is a temporary utility function for tests. It might
1026 * change or be removed at any time without notice.
1027 *
1028 * \param pk Input: the EC or RSA key to import to a PSA key.
1029 * Output: a PK context wrapping that PSA key.
1030 * \param key Output: a PSA key identifier.
1031 * It's the caller's responsibility to call
1032 * psa_destroy_key() on that key identifier after calling
1033 * mbedtls_pk_free() on the PK context.
1034 * \param alg The algorithm to allow for use with that key.
1035 * \param usage The usage to allow for use with that key.
1036 * \param alg2 The secondary algorithm to allow for use with that key.
1037 *
1038 * \return \c 0 if successful.
1039 * \return An Mbed TLS error code otherwise.
1040 */
1041 int mbedtls_pk_wrap_as_opaque(mbedtls_pk_context *pk,
1042 mbedtls_svc_key_id_t *key,
1043 psa_algorithm_t alg,
1044 psa_key_usage_t usage,
1045 psa_algorithm_t alg2);
1046 #endif /* MBEDTLS_USE_PSA_CRYPTO */
1047
1048 #ifdef __cplusplus
1049 }
1050 #endif
1051
1052 #endif /* MBEDTLS_PK_H */
1053