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1 /*
2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 #ifndef OPENSSL_HEADER_RSA_H
11 #define OPENSSL_HEADER_RSA_H
12 
13 #include <openssl/base.h>
14 
15 #include <openssl/engine.h>
16 #include <openssl/ex_data.h>
17 #include <openssl/thread.h>
18 
19 #if defined(__cplusplus)
20 extern "C" {
21 #endif
22 
23 
24 // rsa.h contains functions for handling encryption and signature using RSA.
25 
26 
27 // Allocation and destruction.
28 //
29 // An |RSA| object represents a public or private RSA key. A given object may be
30 // used concurrently on multiple threads by non-mutating functions, provided no
31 // other thread is concurrently calling a mutating function. Unless otherwise
32 // documented, functions which take a |const| pointer are non-mutating and
33 // functions which take a non-|const| pointer are mutating.
34 
35 // RSA_new_public_key returns a new |RSA| object containing a public key with
36 // the specified parameters, or NULL on error or invalid input.
37 OPENSSL_EXPORT RSA *RSA_new_public_key(const BIGNUM *n, const BIGNUM *e);
38 
39 // RSA_new_private_key returns a new |RSA| object containing a private key with
40 // the specified parameters, or NULL on error or invalid input. All parameters
41 // are mandatory and may not be NULL.
42 //
43 // This function creates standard RSA private keys with CRT parameters.
44 OPENSSL_EXPORT RSA *RSA_new_private_key(const BIGNUM *n, const BIGNUM *e,
45                                         const BIGNUM *d, const BIGNUM *p,
46                                         const BIGNUM *q, const BIGNUM *dmp1,
47                                         const BIGNUM *dmq1, const BIGNUM *iqmp);
48 
49 // RSA_new returns a new, empty |RSA| object or NULL on error. Prefer using
50 // |RSA_new_public_key| or |RSA_new_private_key| to import an RSA key.
51 OPENSSL_EXPORT RSA *RSA_new(void);
52 
53 // RSA_new_method acts the same as |RSA_new| but takes an explicit |ENGINE|.
54 OPENSSL_EXPORT RSA *RSA_new_method(const ENGINE *engine);
55 
56 // RSA_free decrements the reference count of |rsa| and frees it if the
57 // reference count drops to zero.
58 OPENSSL_EXPORT void RSA_free(RSA *rsa);
59 
60 // RSA_up_ref increments the reference count of |rsa| and returns one. It does
61 // not mutate |rsa| for thread-safety purposes and may be used concurrently.
62 OPENSSL_EXPORT int RSA_up_ref(RSA *rsa);
63 
64 
65 // Properties.
66 
67 // OPENSSL_RSA_MAX_MODULUS_BITS is the maximum supported RSA modulus, in bits.
68 //
69 // TODO(davidben): Reduce this to 8192.
70 #define OPENSSL_RSA_MAX_MODULUS_BITS 16384
71 
72 // RSA_bits returns the size of |rsa|, in bits.
73 OPENSSL_EXPORT unsigned RSA_bits(const RSA *rsa);
74 
75 // RSA_get0_n returns |rsa|'s public modulus.
76 OPENSSL_EXPORT const BIGNUM *RSA_get0_n(const RSA *rsa);
77 
78 // RSA_get0_e returns |rsa|'s public exponent.
79 OPENSSL_EXPORT const BIGNUM *RSA_get0_e(const RSA *rsa);
80 
81 // RSA_get0_d returns |rsa|'s private exponent. If |rsa| is a public key, this
82 // value will be NULL.
83 OPENSSL_EXPORT const BIGNUM *RSA_get0_d(const RSA *rsa);
84 
85 // RSA_get0_p returns |rsa|'s first private prime factor. If |rsa| is a public
86 // key or lacks its prime factors, this value will be NULL.
87 OPENSSL_EXPORT const BIGNUM *RSA_get0_p(const RSA *rsa);
88 
89 // RSA_get0_q returns |rsa|'s second private prime factor. If |rsa| is a public
90 // key or lacks its prime factors, this value will be NULL.
91 OPENSSL_EXPORT const BIGNUM *RSA_get0_q(const RSA *rsa);
92 
93 // RSA_get0_dmp1 returns d (mod p-1) for |rsa|. If |rsa| is a public key or
94 // lacks CRT parameters, this value will be NULL.
95 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmp1(const RSA *rsa);
96 
97 // RSA_get0_dmq1 returns d (mod q-1) for |rsa|. If |rsa| is a public key or
98 // lacks CRT parameters, this value will be NULL.
99 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmq1(const RSA *rsa);
100 
101 // RSA_get0_iqmp returns q^-1 (mod p). If |rsa| is a public key or lacks CRT
102 // parameters, this value will be NULL.
103 OPENSSL_EXPORT const BIGNUM *RSA_get0_iqmp(const RSA *rsa);
104 
105 // RSA_get0_key sets |*out_n|, |*out_e|, and |*out_d|, if non-NULL, to |rsa|'s
106 // modulus, public exponent, and private exponent, respectively. If |rsa| is a
107 // public key, the private exponent will be set to NULL.
108 OPENSSL_EXPORT void RSA_get0_key(const RSA *rsa, const BIGNUM **out_n,
109                                  const BIGNUM **out_e, const BIGNUM **out_d);
110 
111 // RSA_get0_factors sets |*out_p| and |*out_q|, if non-NULL, to |rsa|'s prime
112 // factors. If |rsa| is a public key, they will be set to NULL.
113 OPENSSL_EXPORT void RSA_get0_factors(const RSA *rsa, const BIGNUM **out_p,
114                                      const BIGNUM **out_q);
115 
116 // RSA_get0_crt_params sets |*out_dmp1|, |*out_dmq1|, and |*out_iqmp|, if
117 // non-NULL, to |rsa|'s CRT parameters. These are d (mod p-1), d (mod q-1) and
118 // q^-1 (mod p), respectively. If |rsa| is a public key, each parameter will be
119 // set to NULL.
120 OPENSSL_EXPORT void RSA_get0_crt_params(const RSA *rsa, const BIGNUM **out_dmp1,
121                                         const BIGNUM **out_dmq1,
122                                         const BIGNUM **out_iqmp);
123 
124 
125 // Setting individual properties.
126 //
127 // These functions allow setting individual properties of an |RSA| object. This
128 // is typically used with |RSA_new| to construct an RSA key field by field.
129 // Prefer instead to use |RSA_new_public_key| and |RSA_new_private_key|. These
130 // functions defer some initialization to the first use of an |RSA| object. This
131 // means invalid inputs may be caught late.
132 //
133 // TODO(crbug.com/boringssl/316): This deferred initialization also causes
134 // performance problems in multi-threaded applications. The preferred APIs
135 // currently have the same issues, but they will initialize eagerly in the
136 // future.
137 
138 // RSA_set0_key sets |rsa|'s modulus, public exponent, and private exponent to
139 // |n|, |e|, and |d| respectively, if non-NULL. On success, it takes ownership
140 // of each argument and returns one. Otherwise, it returns zero.
141 //
142 // |d| may be NULL, but |n| and |e| must either be non-NULL or already
143 // configured on |rsa|.
144 //
145 // It is an error to call this function after |rsa| has been used for a
146 // cryptographic operation. Construct a new |RSA| object instead.
147 OPENSSL_EXPORT int RSA_set0_key(RSA *rsa, BIGNUM *n, BIGNUM *e, BIGNUM *d);
148 
149 // RSA_set0_factors sets |rsa|'s prime factors to |p| and |q|, if non-NULL, and
150 // takes ownership of them. On success, it takes ownership of each argument and
151 // returns one. Otherwise, it returns zero.
152 //
153 // Each argument must either be non-NULL or already configured on |rsa|.
154 //
155 // It is an error to call this function after |rsa| has been used for a
156 // cryptographic operation. Construct a new |RSA| object instead.
157 OPENSSL_EXPORT int RSA_set0_factors(RSA *rsa, BIGNUM *p, BIGNUM *q);
158 
159 // RSA_set0_crt_params sets |rsa|'s CRT parameters to |dmp1|, |dmq1|, and
160 // |iqmp|, if non-NULL, and takes ownership of them. On success, it takes
161 // ownership of its parameters and returns one. Otherwise, it returns zero.
162 //
163 // Each argument must either be non-NULL or already configured on |rsa|.
164 //
165 // It is an error to call this function after |rsa| has been used for a
166 // cryptographic operation. Construct a new |RSA| object instead.
167 OPENSSL_EXPORT int RSA_set0_crt_params(RSA *rsa, BIGNUM *dmp1, BIGNUM *dmq1,
168                                        BIGNUM *iqmp);
169 
170 
171 // Key generation.
172 
173 // RSA_generate_key_ex generates a new RSA key where the modulus has size
174 // |bits| and the public exponent is |e|. If unsure, |RSA_F4| is a good value
175 // for |e|. If |cb| is not NULL then it is called during the key generation
176 // process. In addition to the calls documented for |BN_generate_prime_ex|, it
177 // is called with event=2 when the n'th prime is rejected as unsuitable and
178 // with event=3 when a suitable value for |p| is found.
179 //
180 // It returns one on success or zero on error.
181 OPENSSL_EXPORT int RSA_generate_key_ex(RSA *rsa, int bits, const BIGNUM *e,
182                                        BN_GENCB *cb);
183 
184 // RSA_generate_key_fips behaves like |RSA_generate_key_ex| but performs
185 // additional checks for FIPS compliance. The public exponent is always 65537
186 // and |bits| must be either 2048 or 3072.
187 OPENSSL_EXPORT int RSA_generate_key_fips(RSA *rsa, int bits, BN_GENCB *cb);
188 
189 
190 // Encryption / Decryption
191 //
192 // These functions are considered non-mutating for thread-safety purposes and
193 // may be used concurrently.
194 
195 // RSA_PKCS1_PADDING denotes PKCS#1 v1.5 padding. When used with encryption,
196 // this is RSAES-PKCS1-v1_5. When used with signing, this is RSASSA-PKCS1-v1_5.
197 //
198 // WARNING: The RSAES-PKCS1-v1_5 encryption scheme is vulnerable to a
199 // chosen-ciphertext attack. Decrypting attacker-supplied ciphertext with
200 // RSAES-PKCS1-v1_5 may give the attacker control over your private key. This
201 // does not impact the RSASSA-PKCS1-v1_5 signature scheme. See "Chosen
202 // Ciphertext Attacks Against Protocols Based on the RSA Encryption Standard
203 // PKCS #1", Daniel Bleichenbacher, Advances in Cryptology (Crypto '98).
204 #define RSA_PKCS1_PADDING 1
205 
206 // RSA_NO_PADDING denotes a raw RSA operation.
207 #define RSA_NO_PADDING 3
208 
209 // RSA_PKCS1_OAEP_PADDING denotes the RSAES-OAEP encryption scheme.
210 #define RSA_PKCS1_OAEP_PADDING 4
211 
212 // RSA_PKCS1_PSS_PADDING denotes the RSASSA-PSS signature scheme. This value may
213 // not be passed into |RSA_sign_raw|, only |EVP_PKEY_CTX_set_rsa_padding|. See
214 // also |RSA_sign_pss_mgf1| and |RSA_verify_pss_mgf1|.
215 #define RSA_PKCS1_PSS_PADDING 6
216 
217 // RSA_encrypt encrypts |in_len| bytes from |in| to the public key from |rsa|
218 // and writes, at most, |max_out| bytes of encrypted data to |out|. The
219 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
220 //
221 // It returns 1 on success or zero on error.
222 //
223 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
224 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
225 OPENSSL_EXPORT int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out,
226                                size_t max_out, const uint8_t *in, size_t in_len,
227                                int padding);
228 
229 // RSA_decrypt decrypts |in_len| bytes from |in| with the private key from
230 // |rsa| and writes, at most, |max_out| bytes of plaintext to |out|. The
231 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
232 //
233 // It returns 1 on success or zero on error.
234 //
235 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
236 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
237 //
238 // WARNING: Passing |RSA_PKCS1_PADDING| into this function is deprecated and
239 // insecure. RSAES-PKCS1-v1_5 is vulnerable to a chosen-ciphertext attack.
240 // Decrypting attacker-supplied ciphertext with RSAES-PKCS1-v1_5 may give the
241 // attacker control over your private key. See "Chosen Ciphertext Attacks
242 // Against Protocols Based on the RSA Encryption Standard PKCS #1", Daniel
243 // Bleichenbacher, Advances in Cryptology (Crypto '98).
244 //
245 // In some limited cases, such as TLS RSA key exchange, it is possible to
246 // mitigate this flaw with custom, protocol-specific padding logic. This
247 // should be implemented with |RSA_NO_PADDING|, not |RSA_PKCS1_PADDING|.
248 OPENSSL_EXPORT int RSA_decrypt(RSA *rsa, size_t *out_len, uint8_t *out,
249                                size_t max_out, const uint8_t *in, size_t in_len,
250                                int padding);
251 
252 // RSA_public_encrypt encrypts |flen| bytes from |from| to the public key in
253 // |rsa| and writes the encrypted data to |to|. The |to| buffer must have at
254 // least |RSA_size| bytes of space. It returns the number of bytes written, or
255 // -1 on error. The |padding| argument must be one of the |RSA_*_PADDING|
256 // values. If in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
257 //
258 // WARNING: this function is dangerous because it breaks the usual return value
259 // convention. Use |RSA_encrypt| instead.
260 OPENSSL_EXPORT int RSA_public_encrypt(size_t flen, const uint8_t *from,
261                                       uint8_t *to, RSA *rsa, int padding);
262 
263 // RSA_private_decrypt decrypts |flen| bytes from |from| with the public key in
264 // |rsa| and writes the plaintext to |to|. The |to| buffer must have at least
265 // |RSA_size| bytes of space. It returns the number of bytes written, or -1 on
266 // error. The |padding| argument must be one of the |RSA_*_PADDING| values. If
267 // in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols. Passing
268 // |RSA_PKCS1_PADDING| into this function is deprecated and insecure. See
269 // |RSA_decrypt|.
270 //
271 // WARNING: this function is dangerous because it breaks the usual return value
272 // convention. Use |RSA_decrypt| instead.
273 OPENSSL_EXPORT int RSA_private_decrypt(size_t flen, const uint8_t *from,
274                                        uint8_t *to, RSA *rsa, int padding);
275 
276 
277 // Signing / Verification
278 //
279 // These functions are considered non-mutating for thread-safety purposes and
280 // may be used concurrently.
281 
282 // RSA_sign signs |digest_len| bytes of digest from |digest| with |rsa| using
283 // RSASSA-PKCS1-v1_5. It writes, at most, |RSA_size(rsa)| bytes to |out|. On
284 // successful return, the actual number of bytes written is written to
285 // |*out_len|.
286 //
287 // The |hash_nid| argument identifies the hash function used to calculate
288 // |digest| and is embedded in the resulting signature. For example, it might be
289 // |NID_sha256|.
290 //
291 // It returns 1 on success and zero on error.
292 //
293 // WARNING: |digest| must be the result of hashing the data to be signed with
294 // |hash_nid|. Passing unhashed inputs will not result in a secure signature
295 // scheme.
296 OPENSSL_EXPORT int RSA_sign(int hash_nid, const uint8_t *digest,
297                             size_t digest_len, uint8_t *out, unsigned *out_len,
298                             RSA *rsa);
299 
300 // RSA_sign_pss_mgf1 signs |digest_len| bytes from |digest| with the public key
301 // from |rsa| using RSASSA-PSS with MGF1 as the mask generation function. It
302 // writes, at most, |max_out| bytes of signature data to |out|. The |max_out|
303 // argument must be, at least, |RSA_size| in order to ensure success. It returns
304 // 1 on success or zero on error.
305 //
306 // The |md| and |mgf1_md| arguments identify the hash used to calculate |digest|
307 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
308 // used.
309 //
310 // |salt_len| specifies the expected salt length in bytes. If |salt_len| is -1,
311 // then the salt length is the same as the hash length. If -2, then the salt
312 // length is maximal given the size of |rsa|. If unsure, use -1.
313 //
314 // WARNING: |digest| must be the result of hashing the data to be signed with
315 // |md|. Passing unhashed inputs will not result in a secure signature scheme.
316 OPENSSL_EXPORT int RSA_sign_pss_mgf1(RSA *rsa, size_t *out_len, uint8_t *out,
317                                      size_t max_out, const uint8_t *digest,
318                                      size_t digest_len, const EVP_MD *md,
319                                      const EVP_MD *mgf1_md, int salt_len);
320 
321 // RSA_sign_raw performs the private key portion of computing a signature with
322 // |rsa|. It writes, at most, |max_out| bytes of signature data to |out|. The
323 // |max_out| argument must be, at least, |RSA_size| in order to ensure the
324 // output fits. It returns 1 on success or zero on error.
325 //
326 // If |padding| is |RSA_PKCS1_PADDING|, this function wraps |in| with the
327 // padding portion of RSASSA-PKCS1-v1_5 and then performs the raw private key
328 // operation. The caller is responsible for hashing the input and wrapping it in
329 // a DigestInfo structure.
330 //
331 // If |padding| is |RSA_NO_PADDING|, this function only performs the raw private
332 // key operation, interpreting |in| as a integer modulo n. The caller is
333 // responsible for hashing the input and encoding it for the signature scheme
334 // being implemented.
335 //
336 // WARNING: This function is a building block for a signature scheme, not a
337 // complete one. |in| must be the result of hashing and encoding the data as
338 // needed for the scheme being implemented. Passing in arbitrary inputs will not
339 // result in a secure signature scheme.
340 OPENSSL_EXPORT int RSA_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out,
341                                 size_t max_out, const uint8_t *in,
342                                 size_t in_len, int padding);
343 
344 // RSA_verify verifies that |sig_len| bytes from |sig| are a valid,
345 // RSASSA-PKCS1-v1_5 signature of |digest_len| bytes at |digest| by |rsa|.
346 //
347 // The |hash_nid| argument identifies the hash function used to calculate
348 // |digest| and is embedded in the resulting signature in order to prevent hash
349 // confusion attacks. For example, it might be |NID_sha256|.
350 //
351 // It returns one if the signature is valid and zero otherwise.
352 //
353 // WARNING: this differs from the original, OpenSSL function which additionally
354 // returned -1 on error.
355 //
356 // WARNING: |digest| must be the result of hashing the data to be verified with
357 // |hash_nid|. Passing unhashed input will not result in a secure signature
358 // scheme.
359 OPENSSL_EXPORT int RSA_verify(int hash_nid, const uint8_t *digest,
360                               size_t digest_len, const uint8_t *sig,
361                               size_t sig_len, RSA *rsa);
362 
363 // RSA_verify_pss_mgf1 verifies that |sig_len| bytes from |sig| are a valid,
364 // RSASSA-PSS signature of |digest_len| bytes at |digest| by |rsa|. It returns
365 // one if the signature is valid and zero otherwise. MGF1 is used as the mask
366 // generation function.
367 //
368 // The |md| and |mgf1_md| arguments identify the hash used to calculate |digest|
369 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
370 // used. |salt_len| specifies the expected salt length in bytes.
371 //
372 // If |salt_len| is -1, then the salt length is the same as the hash length. If
373 // -2, then the salt length is recovered and all values accepted. If unsure, use
374 // -1.
375 //
376 // WARNING: |digest| must be the result of hashing the data to be verified with
377 // |md|. Passing unhashed input will not result in a secure signature scheme.
378 OPENSSL_EXPORT int RSA_verify_pss_mgf1(RSA *rsa, const uint8_t *digest,
379                                        size_t digest_len, const EVP_MD *md,
380                                        const EVP_MD *mgf1_md, int salt_len,
381                                        const uint8_t *sig, size_t sig_len);
382 
383 // RSA_verify_raw performs the public key portion of verifying |in_len| bytes of
384 // signature from |in| using the public key from |rsa|. On success, it returns
385 // one and writes, at most, |max_out| bytes of output to |out|. The |max_out|
386 // argument must be, at least, |RSA_size| in order to ensure the output fits. On
387 // failure or invalid input, it returns zero.
388 //
389 // If |padding| is |RSA_PKCS1_PADDING|, this function checks the padding portion
390 // of RSASSA-PKCS1-v1_5 and outputs the remainder of the encoded digest. The
391 // caller is responsible for checking the output is a DigestInfo-wrapped digest
392 // of the message.
393 //
394 // If |padding| is |RSA_NO_PADDING|, this function only performs the raw public
395 // key operation. The caller is responsible for checking the output is a valid
396 // result for the signature scheme being implemented.
397 //
398 // WARNING: This function is a building block for a signature scheme, not a
399 // complete one. Checking for arbitrary strings in |out| will not result in a
400 // secure signature scheme.
401 OPENSSL_EXPORT int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out,
402                                   size_t max_out, const uint8_t *in,
403                                   size_t in_len, int padding);
404 
405 // RSA_private_encrypt performs the private key portion of computing a signature
406 // with |rsa|. It takes |flen| bytes from |from| as input and writes the result
407 // to |to|. The |to| buffer must have at least |RSA_size| bytes of space. It
408 // returns the number of bytes written, or -1 on error.
409 //
410 // For the interpretation of |padding| and the input, see |RSA_sign_raw|.
411 //
412 // WARNING: This function is a building block for a signature scheme, not a
413 // complete one. See |RSA_sign_raw| for details.
414 //
415 // WARNING: This function is dangerous because it breaks the usual return value
416 // convention. Use |RSA_sign_raw| instead.
417 OPENSSL_EXPORT int RSA_private_encrypt(size_t flen, const uint8_t *from,
418                                        uint8_t *to, RSA *rsa, int padding);
419 
420 // RSA_public_decrypt performs the public key portion of verifying |flen| bytes
421 // of signature from |from| using the public key from |rsa|. It writes the
422 // result to |to|, which must have at least |RSA_size| bytes of space. It
423 // returns the number of bytes written, or -1 on error.
424 //
425 // For the interpretation of |padding| and the result, see |RSA_verify_raw|.
426 //
427 // WARNING: This function is a building block for a signature scheme, not a
428 // complete one. See |RSA_verify_raw| for details.
429 //
430 // WARNING: This function is dangerous because it breaks the usual return value
431 // convention. Use |RSA_verify_raw| instead.
432 OPENSSL_EXPORT int RSA_public_decrypt(size_t flen, const uint8_t *from,
433                                       uint8_t *to, RSA *rsa, int padding);
434 
435 
436 // Utility functions.
437 
438 // RSA_size returns the number of bytes in the modulus, which is also the size
439 // of a signature or encrypted value using |rsa|.
440 OPENSSL_EXPORT unsigned RSA_size(const RSA *rsa);
441 
442 // RSA_is_opaque returns one if |rsa| is opaque and doesn't expose its key
443 // material. Otherwise it returns zero.
444 OPENSSL_EXPORT int RSA_is_opaque(const RSA *rsa);
445 
446 // RSAPublicKey_dup allocates a fresh |RSA| and copies the public key from
447 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
448 OPENSSL_EXPORT RSA *RSAPublicKey_dup(const RSA *rsa);
449 
450 // RSAPrivateKey_dup allocates a fresh |RSA| and copies the private key from
451 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
452 OPENSSL_EXPORT RSA *RSAPrivateKey_dup(const RSA *rsa);
453 
454 // RSA_check_key performs basic validity tests on |rsa|. It returns one if
455 // they pass and zero otherwise. Opaque keys and public keys always pass. If it
456 // returns zero then a more detailed error is available on the error queue.
457 OPENSSL_EXPORT int RSA_check_key(const RSA *rsa);
458 
459 // RSA_check_fips performs public key validity tests on |key|. It returns one if
460 // they pass and zero otherwise. Opaque keys always fail. This function does not
461 // mutate |rsa| for thread-safety purposes and may be used concurrently.
462 OPENSSL_EXPORT int RSA_check_fips(RSA *key);
463 
464 // RSA_verify_PKCS1_PSS_mgf1 verifies that |EM| is a correct PSS padding of
465 // |mHash|, where |mHash| is a digest produced by |Hash|. |EM| must point to
466 // exactly |RSA_size(rsa)| bytes of data. The |mgf1Hash| argument specifies the
467 // hash function for generating the mask. If NULL, |Hash| is used. The |sLen|
468 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
469 // the salt length is the same as the hash length. If -2, then the salt length
470 // is recovered and all values accepted.
471 //
472 // If unsure, use -1.
473 //
474 // It returns one on success or zero on error.
475 //
476 // This function implements only the low-level padding logic. Use
477 // |RSA_verify_pss_mgf1| instead.
478 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS_mgf1(const RSA *rsa,
479                                              const uint8_t *mHash,
480                                              const EVP_MD *Hash,
481                                              const EVP_MD *mgf1Hash,
482                                              const uint8_t *EM, int sLen);
483 
484 // RSA_padding_add_PKCS1_PSS_mgf1 writes a PSS padding of |mHash| to |EM|,
485 // where |mHash| is a digest produced by |Hash|. |RSA_size(rsa)| bytes of
486 // output will be written to |EM|. The |mgf1Hash| argument specifies the hash
487 // function for generating the mask. If NULL, |Hash| is used. The |sLen|
488 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
489 // the salt length is the same as the hash length. If -2, then the salt length
490 // is maximal given the space in |EM|.
491 //
492 // It returns one on success or zero on error.
493 //
494 // This function implements only the low-level padding logic. Use
495 // |RSA_sign_pss_mgf1| instead.
496 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS_mgf1(const RSA *rsa, uint8_t *EM,
497                                                   const uint8_t *mHash,
498                                                   const EVP_MD *Hash,
499                                                   const EVP_MD *mgf1Hash,
500                                                   int sLen);
501 
502 // RSA_padding_add_PKCS1_OAEP_mgf1 writes an OAEP padding of |from| to |to|
503 // with the given parameters and hash functions. If |md| is NULL then SHA-1 is
504 // used. If |mgf1md| is NULL then the value of |md| is used (which means SHA-1
505 // if that, in turn, is NULL).
506 //
507 // It returns one on success or zero on error.
508 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP_mgf1(
509     uint8_t *to, size_t to_len, const uint8_t *from, size_t from_len,
510     const uint8_t *param, size_t param_len, const EVP_MD *md,
511     const EVP_MD *mgf1md);
512 
513 // RSA_add_pkcs1_prefix builds a version of |digest| prefixed with the
514 // DigestInfo header for the given hash function and sets |out_msg| to point to
515 // it. On successful return, if |*is_alloced| is one, the caller must release
516 // |*out_msg| with |OPENSSL_free|.
517 OPENSSL_EXPORT int RSA_add_pkcs1_prefix(uint8_t **out_msg, size_t *out_msg_len,
518                                         int *is_alloced, int hash_nid,
519                                         const uint8_t *digest,
520                                         size_t digest_len);
521 
522 
523 // ASN.1 functions.
524 
525 // RSA_parse_public_key parses a DER-encoded RSAPublicKey structure (RFC 8017)
526 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
527 // error.
528 OPENSSL_EXPORT RSA *RSA_parse_public_key(CBS *cbs);
529 
530 // RSA_public_key_from_bytes parses |in| as a DER-encoded RSAPublicKey structure
531 // (RFC 8017). It returns a newly-allocated |RSA| or NULL on error.
532 OPENSSL_EXPORT RSA *RSA_public_key_from_bytes(const uint8_t *in, size_t in_len);
533 
534 // RSA_marshal_public_key marshals |rsa| as a DER-encoded RSAPublicKey structure
535 // (RFC 8017) and appends the result to |cbb|. It returns one on success and
536 // zero on failure.
537 OPENSSL_EXPORT int RSA_marshal_public_key(CBB *cbb, const RSA *rsa);
538 
539 // RSA_public_key_to_bytes marshals |rsa| as a DER-encoded RSAPublicKey
540 // structure (RFC 8017) and, on success, sets |*out_bytes| to a newly allocated
541 // buffer containing the result and returns one. Otherwise, it returns zero. The
542 // result should be freed with |OPENSSL_free|.
543 OPENSSL_EXPORT int RSA_public_key_to_bytes(uint8_t **out_bytes, size_t *out_len,
544                                            const RSA *rsa);
545 
546 // RSA_parse_private_key parses a DER-encoded RSAPrivateKey structure (RFC 8017)
547 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
548 // error.
549 OPENSSL_EXPORT RSA *RSA_parse_private_key(CBS *cbs);
550 
551 // RSA_private_key_from_bytes parses |in| as a DER-encoded RSAPrivateKey
552 // structure (RFC 8017). It returns a newly-allocated |RSA| or NULL on error.
553 OPENSSL_EXPORT RSA *RSA_private_key_from_bytes(const uint8_t *in,
554                                                size_t in_len);
555 
556 // RSA_marshal_private_key marshals |rsa| as a DER-encoded RSAPrivateKey
557 // structure (RFC 8017) and appends the result to |cbb|. It returns one on
558 // success and zero on failure.
559 OPENSSL_EXPORT int RSA_marshal_private_key(CBB *cbb, const RSA *rsa);
560 
561 // RSA_private_key_to_bytes marshals |rsa| as a DER-encoded RSAPrivateKey
562 // structure (RFC 8017) and, on success, sets |*out_bytes| to a newly allocated
563 // buffer containing the result and returns one. Otherwise, it returns zero. The
564 // result should be freed with |OPENSSL_free|.
565 OPENSSL_EXPORT int RSA_private_key_to_bytes(uint8_t **out_bytes,
566                                             size_t *out_len, const RSA *rsa);
567 
568 
569 // Obscure RSA variants.
570 //
571 // These functions allow creating RSA keys with obscure combinations of
572 // parameters.
573 
574 // RSA_new_private_key_no_crt behaves like |RSA_new_private_key| but constructs
575 // an RSA key without CRT coefficients.
576 //
577 // Keys created by this function will be less performant and cannot be
578 // serialized.
579 OPENSSL_EXPORT RSA *RSA_new_private_key_no_crt(const BIGNUM *n, const BIGNUM *e,
580                                                const BIGNUM *d);
581 
582 // RSA_new_private_key_no_e behaves like |RSA_new_private_key| but constructs an
583 // RSA key without CRT parameters or public exponent.
584 //
585 // Keys created by this function will be less performant, cannot be serialized,
586 // and lack hardening measures that protect against side channels and fault
587 // attacks.
588 OPENSSL_EXPORT RSA *RSA_new_private_key_no_e(const BIGNUM *n, const BIGNUM *d);
589 
590 // RSA_new_public_key_large_e behaves like |RSA_new_public_key| but allows any
591 // |e| up to |n|.
592 //
593 // BoringSSL typically bounds public exponents as a denial-of-service
594 // mitigation. Keys created by this function may perform worse than those
595 // created by |RSA_new_public_key|.
596 OPENSSL_EXPORT RSA *RSA_new_public_key_large_e(const BIGNUM *n,
597                                                const BIGNUM *e);
598 
599 // RSA_new_private_key_large_e behaves like |RSA_new_private_key| but allows any
600 // |e| up to |n|.
601 //
602 // BoringSSL typically bounds public exponents as a denial-of-service
603 // mitigation. Keys created by this function may perform worse than those
604 // created by |RSA_new_private_key|.
605 OPENSSL_EXPORT RSA *RSA_new_private_key_large_e(
606     const BIGNUM *n, const BIGNUM *e, const BIGNUM *d, const BIGNUM *p,
607     const BIGNUM *q, const BIGNUM *dmp1, const BIGNUM *dmq1,
608     const BIGNUM *iqmp);
609 
610 
611 // ex_data functions.
612 //
613 // See |ex_data.h| for details.
614 
615 OPENSSL_EXPORT int RSA_get_ex_new_index(long argl, void *argp,
616                                         CRYPTO_EX_unused *unused,
617                                         CRYPTO_EX_dup *dup_unused,
618                                         CRYPTO_EX_free *free_func);
619 OPENSSL_EXPORT int RSA_set_ex_data(RSA *rsa, int idx, void *arg);
620 OPENSSL_EXPORT void *RSA_get_ex_data(const RSA *rsa, int idx);
621 
622 
623 // Flags.
624 
625 // RSA_FLAG_OPAQUE specifies that this RSA_METHOD does not expose its key
626 // material. This may be set if, for instance, it is wrapping some other crypto
627 // API, like a platform key store.
628 #define RSA_FLAG_OPAQUE 1
629 
630 // RSA_FLAG_NO_BLINDING disables blinding of private operations, which is a
631 // dangerous thing to do. This flag is set internally as part of self-tests but
632 // is otherwise impossible to set externally.
633 #define RSA_FLAG_NO_BLINDING 8
634 
635 // RSA_FLAG_EXT_PKEY is deprecated and ignored.
636 #define RSA_FLAG_EXT_PKEY 0x20
637 
638 // RSA_FLAG_NO_PUBLIC_EXPONENT indicates that private keys without a public
639 // exponent are allowed. This is an internal constant. Use
640 // |RSA_new_private_key_no_e| to construct such keys.
641 #define RSA_FLAG_NO_PUBLIC_EXPONENT 0x40
642 
643 // RSA_FLAG_LARGE_PUBLIC_EXPONENT indicates that keys with a large public
644 // exponent are allowed. This is an internal constant. Use
645 // |RSA_new_public_key_large_e| and |RSA_new_private_key_large_e| to construct
646 // such keys.
647 #define RSA_FLAG_LARGE_PUBLIC_EXPONENT 0x80
648 
649 
650 // RSA public exponent values.
651 
652 #define RSA_3 0x3
653 #define RSA_F4 0x10001
654 
655 
656 // Deprecated functions.
657 
658 #define RSA_METHOD_FLAG_NO_CHECK RSA_FLAG_OPAQUE
659 
660 // RSA_flags returns the flags for |rsa|. These are a bitwise OR of |RSA_FLAG_*|
661 // constants.
662 OPENSSL_EXPORT int RSA_flags(const RSA *rsa);
663 
664 // RSA_test_flags returns the subset of flags in |flags| which are set in |rsa|.
665 OPENSSL_EXPORT int RSA_test_flags(const RSA *rsa, int flags);
666 
667 // RSA_blinding_on returns one.
668 OPENSSL_EXPORT int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
669 
670 // RSA_blinding_off does nothing.
671 OPENSSL_EXPORT void RSA_blinding_off(RSA *rsa);
672 
673 // RSA_generate_key behaves like |RSA_generate_key_ex|, which is what you
674 // should use instead. It returns NULL on error, or a newly-allocated |RSA| on
675 // success. This function is provided for compatibility only. The |callback|
676 // and |cb_arg| parameters must be NULL.
677 OPENSSL_EXPORT RSA *RSA_generate_key(int bits, uint64_t e, void *callback,
678                                      void *cb_arg);
679 
680 // d2i_RSAPublicKey parses a DER-encoded RSAPublicKey structure (RFC 8017) from
681 // |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
682 //
683 // Use |RSA_parse_public_key| instead.
684 OPENSSL_EXPORT RSA *d2i_RSAPublicKey(RSA **out, const uint8_t **inp, long len);
685 
686 // i2d_RSAPublicKey marshals |in| to a DER-encoded RSAPublicKey structure (RFC
687 // 8017), as described in |i2d_SAMPLE|.
688 //
689 // Use |RSA_marshal_public_key| instead.
690 OPENSSL_EXPORT int i2d_RSAPublicKey(const RSA *in, uint8_t **outp);
691 
692 // d2i_RSAPrivateKey parses a DER-encoded RSAPrivateKey structure (RFC 8017)
693 // from |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
694 //
695 // Use |RSA_parse_private_key| instead.
696 OPENSSL_EXPORT RSA *d2i_RSAPrivateKey(RSA **out, const uint8_t **inp, long len);
697 
698 // i2d_RSAPrivateKey marshals |in| to a DER-encoded RSAPrivateKey structure (RFC
699 // 8017), as described in |i2d_SAMPLE|.
700 //
701 // Use |RSA_marshal_private_key| instead.
702 OPENSSL_EXPORT int i2d_RSAPrivateKey(const RSA *in, uint8_t **outp);
703 
704 // RSA_padding_add_PKCS1_PSS acts like |RSA_padding_add_PKCS1_PSS_mgf1| but the
705 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
706 //
707 // This function implements only the low-level padding logic. Use
708 // |RSA_sign_pss_mgf1| instead.
709 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS(const RSA *rsa, uint8_t *EM,
710                                              const uint8_t *mHash,
711                                              const EVP_MD *Hash, int sLen);
712 
713 // RSA_verify_PKCS1_PSS acts like |RSA_verify_PKCS1_PSS_mgf1| but the
714 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
715 //
716 // This function implements only the low-level padding logic. Use
717 // |RSA_verify_pss_mgf1| instead.
718 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS(const RSA *rsa, const uint8_t *mHash,
719                                         const EVP_MD *Hash, const uint8_t *EM,
720                                         int sLen);
721 
722 // RSA_padding_add_PKCS1_OAEP acts like |RSA_padding_add_PKCS1_OAEP_mgf1| but
723 // the |md| and |mgf1md| parameters of the latter are implicitly set to NULL,
724 // which means SHA-1.
725 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP(uint8_t *to, size_t to_len,
726                                               const uint8_t *from,
727                                               size_t from_len,
728                                               const uint8_t *param,
729                                               size_t param_len);
730 
731 // RSA_print prints a textual representation of |rsa| to |bio|. It returns one
732 // on success or zero otherwise.
733 OPENSSL_EXPORT int RSA_print(BIO *bio, const RSA *rsa, int indent);
734 
735 // RSA_get0_pss_params returns NULL. In OpenSSL, this function retries RSA-PSS
736 // parameters associated with |RSA| objects, but BoringSSL does not support
737 // the id-RSASSA-PSS key encoding.
738 OPENSSL_EXPORT const RSA_PSS_PARAMS *RSA_get0_pss_params(const RSA *rsa);
739 
740 // RSA_new_method_no_e returns a newly-allocated |RSA| object backed by
741 // |engine|, with a public modulus of |n| and no known public exponent.
742 //
743 // Do not use this function. It exists only to support Conscrypt, whose use
744 // should be replaced with a more sound mechanism. See
745 // https://crbug.com/boringssl/602.
746 OPENSSL_EXPORT RSA *RSA_new_method_no_e(const ENGINE *engine, const BIGNUM *n);
747 
748 
749 struct rsa_meth_st {
750   struct openssl_method_common_st common;
751 
752   void *app_data;
753 
754   int (*init)(RSA *rsa);
755   int (*finish)(RSA *rsa);
756 
757   // size returns the size of the RSA modulus in bytes.
758   size_t (*size)(const RSA *rsa);
759 
760   int (*sign)(int type, const uint8_t *m, unsigned int m_length,
761               uint8_t *sigret, unsigned int *siglen, const RSA *rsa);
762 
763   // These functions mirror the |RSA_*| functions of the same name.
764   int (*sign_raw)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
765                   const uint8_t *in, size_t in_len, int padding);
766   int (*decrypt)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
767                  const uint8_t *in, size_t in_len, int padding);
768 
769   // private_transform takes a big-endian integer from |in|, calculates the
770   // d'th power of it, modulo the RSA modulus and writes the result as a
771   // big-endian integer to |out|. Both |in| and |out| are |len| bytes long and
772   // |len| is always equal to |RSA_size(rsa)|. If the result of the transform
773   // can be represented in fewer than |len| bytes, then |out| must be zero
774   // padded on the left.
775   //
776   // It returns one on success and zero otherwise.
777   //
778   // RSA decrypt and sign operations will call this, thus an ENGINE might wish
779   // to override it in order to avoid having to implement the padding
780   // functionality demanded by those, higher level, operations.
781   int (*private_transform)(RSA *rsa, uint8_t *out, const uint8_t *in,
782                            size_t len);
783 
784   int flags;
785 };
786 
787 
788 #if defined(__cplusplus)
789 }  // extern C
790 
791 extern "C++" {
792 
793 BSSL_NAMESPACE_BEGIN
794 
795 BORINGSSL_MAKE_DELETER(RSA, RSA_free)
796 BORINGSSL_MAKE_UP_REF(RSA, RSA_up_ref)
797 
798 BSSL_NAMESPACE_END
799 
800 }  // extern C++
801 
802 #endif
803 
804 #define RSA_R_BAD_ENCODING 100
805 #define RSA_R_BAD_E_VALUE 101
806 #define RSA_R_BAD_FIXED_HEADER_DECRYPT 102
807 #define RSA_R_BAD_PAD_BYTE_COUNT 103
808 #define RSA_R_BAD_RSA_PARAMETERS 104
809 #define RSA_R_BAD_SIGNATURE 105
810 #define RSA_R_BAD_VERSION 106
811 #define RSA_R_BLOCK_TYPE_IS_NOT_01 107
812 #define RSA_R_BN_NOT_INITIALIZED 108
813 #define RSA_R_CANNOT_RECOVER_MULTI_PRIME_KEY 109
814 #define RSA_R_CRT_PARAMS_ALREADY_GIVEN 110
815 #define RSA_R_CRT_VALUES_INCORRECT 111
816 #define RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN 112
817 #define RSA_R_DATA_TOO_LARGE 113
818 #define RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE 114
819 #define RSA_R_DATA_TOO_LARGE_FOR_MODULUS 115
820 #define RSA_R_DATA_TOO_SMALL 116
821 #define RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE 117
822 #define RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY 118
823 #define RSA_R_D_E_NOT_CONGRUENT_TO_1 119
824 #define RSA_R_EMPTY_PUBLIC_KEY 120
825 #define RSA_R_ENCODE_ERROR 121
826 #define RSA_R_FIRST_OCTET_INVALID 122
827 #define RSA_R_INCONSISTENT_SET_OF_CRT_VALUES 123
828 #define RSA_R_INTERNAL_ERROR 124
829 #define RSA_R_INVALID_MESSAGE_LENGTH 125
830 #define RSA_R_KEY_SIZE_TOO_SMALL 126
831 #define RSA_R_LAST_OCTET_INVALID 127
832 #define RSA_R_MODULUS_TOO_LARGE 128
833 #define RSA_R_MUST_HAVE_AT_LEAST_TWO_PRIMES 129
834 #define RSA_R_NO_PUBLIC_EXPONENT 130
835 #define RSA_R_NULL_BEFORE_BLOCK_MISSING 131
836 #define RSA_R_N_NOT_EQUAL_P_Q 132
837 #define RSA_R_OAEP_DECODING_ERROR 133
838 #define RSA_R_ONLY_ONE_OF_P_Q_GIVEN 134
839 #define RSA_R_OUTPUT_BUFFER_TOO_SMALL 135
840 #define RSA_R_PADDING_CHECK_FAILED 136
841 #define RSA_R_PKCS_DECODING_ERROR 137
842 #define RSA_R_SLEN_CHECK_FAILED 138
843 #define RSA_R_SLEN_RECOVERY_FAILED 139
844 #define RSA_R_TOO_LONG 140
845 #define RSA_R_TOO_MANY_ITERATIONS 141
846 #define RSA_R_UNKNOWN_ALGORITHM_TYPE 142
847 #define RSA_R_UNKNOWN_PADDING_TYPE 143
848 #define RSA_R_VALUE_MISSING 144
849 #define RSA_R_WRONG_SIGNATURE_LENGTH 145
850 #define RSA_R_PUBLIC_KEY_VALIDATION_FAILED 146
851 #define RSA_R_D_OUT_OF_RANGE 147
852 #define RSA_R_BLOCK_TYPE_IS_NOT_02 148
853 
854 #endif  // OPENSSL_HEADER_RSA_H
855