1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #ifndef OPENSSL_HEADER_RSA_H
58 #define OPENSSL_HEADER_RSA_H
59 
60 #include <openssl/base.h>
61 
62 #include <openssl/engine.h>
63 #include <openssl/ex_data.h>
64 #include <openssl/thread.h>
65 
66 #if defined(__cplusplus)
67 extern "C" {
68 #endif
69 
70 
71 // rsa.h contains functions for handling encryption and signature using RSA.
72 
73 
74 // Allocation and destruction.
75 //
76 // An |RSA| object represents a public or private RSA key. A given object may be
77 // used concurrently on multiple threads by non-mutating functions, provided no
78 // other thread is concurrently calling a mutating function. Unless otherwise
79 // documented, functions which take a |const| pointer are non-mutating and
80 // functions which take a non-|const| pointer are mutating.
81 
82 // RSA_new returns a new, empty |RSA| object or NULL on error.
83 OPENSSL_EXPORT RSA *RSA_new(void);
84 
85 // RSA_new_method acts the same as |RSA_new| but takes an explicit |ENGINE|.
86 OPENSSL_EXPORT RSA *RSA_new_method(const ENGINE *engine);
87 
88 // RSA_free decrements the reference count of |rsa| and frees it if the
89 // reference count drops to zero.
90 OPENSSL_EXPORT void RSA_free(RSA *rsa);
91 
92 // RSA_up_ref increments the reference count of |rsa| and returns one. It does
93 // not mutate |rsa| for thread-safety purposes and may be used concurrently.
94 OPENSSL_EXPORT int RSA_up_ref(RSA *rsa);
95 
96 
97 // Properties.
98 
99 // RSA_bits returns the size of |rsa|, in bits.
100 OPENSSL_EXPORT unsigned RSA_bits(const RSA *rsa);
101 
102 // RSA_get0_n returns |rsa|'s public modulus.
103 OPENSSL_EXPORT const BIGNUM *RSA_get0_n(const RSA *rsa);
104 
105 // RSA_get0_e returns |rsa|'s public exponent.
106 OPENSSL_EXPORT const BIGNUM *RSA_get0_e(const RSA *rsa);
107 
108 // RSA_get0_d returns |rsa|'s private exponent. If |rsa| is a public key, this
109 // value will be NULL.
110 OPENSSL_EXPORT const BIGNUM *RSA_get0_d(const RSA *rsa);
111 
112 // RSA_get0_p returns |rsa|'s first private prime factor. If |rsa| is a public
113 // key or lacks its prime factors, this value will be NULL.
114 OPENSSL_EXPORT const BIGNUM *RSA_get0_p(const RSA *rsa);
115 
116 // RSA_get0_q returns |rsa|'s second private prime factor. If |rsa| is a public
117 // key or lacks its prime factors, this value will be NULL.
118 OPENSSL_EXPORT const BIGNUM *RSA_get0_q(const RSA *rsa);
119 
120 // RSA_get0_dmp1 returns d (mod p-1) for |rsa|. If |rsa| is a public key or
121 // lacks CRT parameters, this value will be NULL.
122 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmp1(const RSA *rsa);
123 
124 // RSA_get0_dmq1 returns d (mod q-1) for |rsa|. If |rsa| is a public key or
125 // lacks CRT parameters, this value will be NULL.
126 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmq1(const RSA *rsa);
127 
128 // RSA_get0_iqmp returns q^-1 (mod p). If |rsa| is a public key or lacks CRT
129 // parameters, this value will be NULL.
130 OPENSSL_EXPORT const BIGNUM *RSA_get0_iqmp(const RSA *rsa);
131 
132 // RSA_get0_key sets |*out_n|, |*out_e|, and |*out_d|, if non-NULL, to |rsa|'s
133 // modulus, public exponent, and private exponent, respectively. If |rsa| is a
134 // public key, the private exponent will be set to NULL.
135 OPENSSL_EXPORT void RSA_get0_key(const RSA *rsa, const BIGNUM **out_n,
136                                  const BIGNUM **out_e, const BIGNUM **out_d);
137 
138 // RSA_get0_factors sets |*out_p| and |*out_q|, if non-NULL, to |rsa|'s prime
139 // factors. If |rsa| is a public key, they will be set to NULL.
140 OPENSSL_EXPORT void RSA_get0_factors(const RSA *rsa, const BIGNUM **out_p,
141                                      const BIGNUM **out_q);
142 
143 // RSA_get0_crt_params sets |*out_dmp1|, |*out_dmq1|, and |*out_iqmp|, if
144 // non-NULL, to |rsa|'s CRT parameters. These are d (mod p-1), d (mod q-1) and
145 // q^-1 (mod p), respectively. If |rsa| is a public key, each parameter will be
146 // set to NULL.
147 OPENSSL_EXPORT void RSA_get0_crt_params(const RSA *rsa, const BIGNUM **out_dmp1,
148                                         const BIGNUM **out_dmq1,
149                                         const BIGNUM **out_iqmp);
150 
151 // RSA_set0_key sets |rsa|'s modulus, public exponent, and private exponent to
152 // |n|, |e|, and |d| respectively, if non-NULL. On success, it takes ownership
153 // of each argument and returns one. Otherwise, it returns zero.
154 //
155 // |d| may be NULL, but |n| and |e| must either be non-NULL or already
156 // configured on |rsa|.
157 //
158 // It is an error to call this function after |rsa| has been used for a
159 // cryptographic operation. Construct a new |RSA| object instead.
160 OPENSSL_EXPORT int RSA_set0_key(RSA *rsa, BIGNUM *n, BIGNUM *e, BIGNUM *d);
161 
162 // RSA_set0_factors sets |rsa|'s prime factors to |p| and |q|, if non-NULL, and
163 // takes ownership of them. On success, it takes ownership of each argument and
164 // returns one. Otherwise, it returns zero.
165 //
166 // Each argument must either be non-NULL or already configured on |rsa|.
167 //
168 // It is an error to call this function after |rsa| has been used for a
169 // cryptographic operation. Construct a new |RSA| object instead.
170 OPENSSL_EXPORT int RSA_set0_factors(RSA *rsa, BIGNUM *p, BIGNUM *q);
171 
172 // RSA_set0_crt_params sets |rsa|'s CRT parameters to |dmp1|, |dmq1|, and
173 // |iqmp|, if non-NULL, and takes ownership of them. On success, it takes
174 // ownership of its parameters and returns one. Otherwise, it returns zero.
175 //
176 // Each argument must either be non-NULL or already configured on |rsa|.
177 //
178 // It is an error to call this function after |rsa| has been used for a
179 // cryptographic operation. Construct a new |RSA| object instead.
180 OPENSSL_EXPORT int RSA_set0_crt_params(RSA *rsa, BIGNUM *dmp1, BIGNUM *dmq1,
181                                        BIGNUM *iqmp);
182 
183 
184 // Key generation.
185 
186 // RSA_generate_key_ex generates a new RSA key where the modulus has size
187 // |bits| and the public exponent is |e|. If unsure, |RSA_F4| is a good value
188 // for |e|. If |cb| is not NULL then it is called during the key generation
189 // process. In addition to the calls documented for |BN_generate_prime_ex|, it
190 // is called with event=2 when the n'th prime is rejected as unsuitable and
191 // with event=3 when a suitable value for |p| is found.
192 //
193 // It returns one on success or zero on error.
194 OPENSSL_EXPORT int RSA_generate_key_ex(RSA *rsa, int bits, const BIGNUM *e,
195                                        BN_GENCB *cb);
196 
197 // RSA_generate_key_fips behaves like |RSA_generate_key_ex| but performs
198 // additional checks for FIPS compliance. The public exponent is always 65537
199 // and |bits| must be either 2048 or 3072.
200 OPENSSL_EXPORT int RSA_generate_key_fips(RSA *rsa, int bits, BN_GENCB *cb);
201 
202 
203 // Encryption / Decryption
204 //
205 // These functions are considered non-mutating for thread-safety purposes and
206 // may be used concurrently.
207 
208 // RSA_PKCS1_PADDING denotes PKCS#1 v1.5 padding. When used with encryption,
209 // this is RSAES-PKCS1-v1_5. When used with signing, this is RSASSA-PKCS1-v1_5.
210 #define RSA_PKCS1_PADDING 1
211 
212 // RSA_NO_PADDING denotes a raw RSA operation.
213 #define RSA_NO_PADDING 3
214 
215 // RSA_PKCS1_OAEP_PADDING denotes the RSAES-OAEP encryption scheme.
216 #define RSA_PKCS1_OAEP_PADDING 4
217 
218 // RSA_PKCS1_PSS_PADDING denotes the RSASSA-PSS signature scheme. This value may
219 // not be passed into |RSA_sign_raw|, only |EVP_PKEY_CTX_set_rsa_padding|. See
220 // also |RSA_sign_pss_mgf1| and |RSA_verify_pss_mgf1|.
221 #define RSA_PKCS1_PSS_PADDING 6
222 
223 // RSA_encrypt encrypts |in_len| bytes from |in| to the public key from |rsa|
224 // and writes, at most, |max_out| bytes of encrypted data to |out|. The
225 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
226 //
227 // It returns 1 on success or zero on error.
228 //
229 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
230 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols but
231 // |RSA_PKCS1_PADDING| is most common.
232 OPENSSL_EXPORT int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out,
233                                size_t max_out, const uint8_t *in, size_t in_len,
234                                int padding);
235 
236 // RSA_decrypt decrypts |in_len| bytes from |in| with the private key from
237 // |rsa| and writes, at most, |max_out| bytes of plaintext to |out|. The
238 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
239 //
240 // It returns 1 on success or zero on error.
241 //
242 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
243 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
244 //
245 // Passing |RSA_PKCS1_PADDING| into this function is deprecated and insecure. If
246 // implementing a protocol using RSAES-PKCS1-V1_5, use |RSA_NO_PADDING| and then
247 // check padding in constant-time combined with a swap to a random session key
248 // or other mitigation. See "Chosen Ciphertext Attacks Against Protocols Based
249 // on the RSA Encryption Standard PKCS #1", Daniel Bleichenbacher, Advances in
250 // Cryptology (Crypto '98).
251 OPENSSL_EXPORT int RSA_decrypt(RSA *rsa, size_t *out_len, uint8_t *out,
252                                size_t max_out, const uint8_t *in, size_t in_len,
253                                int padding);
254 
255 // RSA_public_encrypt encrypts |flen| bytes from |from| to the public key in
256 // |rsa| and writes the encrypted data to |to|. The |to| buffer must have at
257 // least |RSA_size| bytes of space. It returns the number of bytes written, or
258 // -1 on error. The |padding| argument must be one of the |RSA_*_PADDING|
259 // values. If in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols but
260 // |RSA_PKCS1_PADDING| is most common.
261 //
262 // WARNING: this function is dangerous because it breaks the usual return value
263 // convention. Use |RSA_encrypt| instead.
264 OPENSSL_EXPORT int RSA_public_encrypt(size_t flen, const uint8_t *from,
265                                       uint8_t *to, RSA *rsa, int padding);
266 
267 // RSA_private_decrypt decrypts |flen| bytes from |from| with the public key in
268 // |rsa| and writes the plaintext to |to|. The |to| buffer must have at least
269 // |RSA_size| bytes of space. It returns the number of bytes written, or -1 on
270 // error. The |padding| argument must be one of the |RSA_*_PADDING| values. If
271 // in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols. Passing
272 // |RSA_PKCS1_PADDING| into this function is deprecated and insecure. See
273 // |RSA_decrypt|.
274 //
275 // WARNING: this function is dangerous because it breaks the usual return value
276 // convention. Use |RSA_decrypt| instead.
277 OPENSSL_EXPORT int RSA_private_decrypt(size_t flen, const uint8_t *from,
278                                        uint8_t *to, RSA *rsa, int padding);
279 
280 
281 // Signing / Verification
282 //
283 // These functions are considered non-mutating for thread-safety purposes and
284 // may be used concurrently.
285 
286 // RSA_sign signs |in_len| bytes of digest from |in| with |rsa| using
287 // RSASSA-PKCS1-v1_5. It writes, at most, |RSA_size(rsa)| bytes to |out|. On
288 // successful return, the actual number of bytes written is written to
289 // |*out_len|.
290 //
291 // The |hash_nid| argument identifies the hash function used to calculate |in|
292 // and is embedded in the resulting signature. For example, it might be
293 // |NID_sha256|.
294 //
295 // It returns 1 on success and zero on error.
296 OPENSSL_EXPORT int RSA_sign(int hash_nid, const uint8_t *in,
297                             unsigned int in_len, uint8_t *out,
298                             unsigned int *out_len, RSA *rsa);
299 
300 // RSA_sign_pss_mgf1 signs |in_len| bytes from |in| with the public key from
301 // |rsa| using RSASSA-PSS with MGF1 as the mask generation function. It writes,
302 // at most, |max_out| bytes of signature data to |out|. The |max_out| argument
303 // must be, at least, |RSA_size| in order to ensure success. It returns 1 on
304 // success or zero on error.
305 //
306 // The |md| and |mgf1_md| arguments identify the hash used to calculate |msg|
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 OPENSSL_EXPORT int RSA_sign_pss_mgf1(RSA *rsa, size_t *out_len, uint8_t *out,
314                                      size_t max_out, const uint8_t *in,
315                                      size_t in_len, const EVP_MD *md,
316                                      const EVP_MD *mgf1_md, int salt_len);
317 
318 // RSA_sign_raw signs |in_len| bytes from |in| with the public key from |rsa|
319 // and writes, at most, |max_out| bytes of signature data to |out|. The
320 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
321 //
322 // It returns 1 on success or zero on error.
323 //
324 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
325 // doubt, |RSA_PKCS1_PADDING| is the most common but |RSA_PKCS1_PSS_PADDING|
326 // (via |RSA_sign_pss_mgf1| or the |EVP_PKEY| interface) is preferred for new
327 // protocols.
328 OPENSSL_EXPORT int RSA_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out,
329                                 size_t max_out, const uint8_t *in,
330                                 size_t in_len, int padding);
331 
332 // RSA_verify verifies that |sig_len| bytes from |sig| are a valid,
333 // RSASSA-PKCS1-v1_5 signature of |msg_len| bytes at |msg| by |rsa|.
334 //
335 // The |hash_nid| argument identifies the hash function used to calculate |msg|
336 // and is embedded in the resulting signature in order to prevent hash
337 // confusion attacks. For example, it might be |NID_sha256|.
338 //
339 // It returns one if the signature is valid and zero otherwise.
340 //
341 // WARNING: this differs from the original, OpenSSL function which additionally
342 // returned -1 on error.
343 OPENSSL_EXPORT int RSA_verify(int hash_nid, const uint8_t *msg, size_t msg_len,
344                               const uint8_t *sig, size_t sig_len, RSA *rsa);
345 
346 // RSA_verify_pss_mgf1 verifies that |sig_len| bytes from |sig| are a valid,
347 // RSASSA-PSS signature of |msg_len| bytes at |msg| by |rsa|. It returns one if
348 // the signature is valid and zero otherwise. MGF1 is used as the mask
349 // generation function.
350 //
351 // The |md| and |mgf1_md| arguments identify the hash used to calculate |msg|
352 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
353 // used. |salt_len| specifies the expected salt length in bytes.
354 //
355 // If |salt_len| is -1, then the salt length is the same as the hash length. If
356 // -2, then the salt length is recovered and all values accepted. If unsure, use
357 // -1.
358 OPENSSL_EXPORT int RSA_verify_pss_mgf1(RSA *rsa, const uint8_t *msg,
359                                        size_t msg_len, const EVP_MD *md,
360                                        const EVP_MD *mgf1_md, int salt_len,
361                                        const uint8_t *sig, size_t sig_len);
362 
363 // RSA_verify_raw verifies |in_len| bytes of signature from |in| using the
364 // public key from |rsa| and writes, at most, |max_out| bytes of plaintext to
365 // |out|. The |max_out| argument must be, at least, |RSA_size| in order to
366 // ensure success.
367 //
368 // It returns 1 on success or zero on error.
369 //
370 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
371 // doubt, |RSA_PKCS1_PADDING| is the most common but |RSA_PKCS1_PSS_PADDING|
372 // (via |RSA_verify_pss_mgf1| or the |EVP_PKEY| interface) is preferred for new
373 // protocols.
374 OPENSSL_EXPORT int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out,
375                                   size_t max_out, const uint8_t *in,
376                                   size_t in_len, int padding);
377 
378 // RSA_private_encrypt encrypts |flen| bytes from |from| with the private key in
379 // |rsa| and writes the encrypted data to |to|. The |to| buffer must have at
380 // least |RSA_size| bytes of space. It returns the number of bytes written, or
381 // -1 on error. The |padding| argument must be one of the |RSA_*_PADDING|
382 // values. If in doubt, |RSA_PKCS1_PADDING| is the most common but
383 // |RSA_PKCS1_PSS_PADDING| (via the |EVP_PKEY| interface) is preferred for new
384 // protocols.
385 //
386 // WARNING: this function is dangerous because it breaks the usual return value
387 // convention. Use |RSA_sign_raw| instead.
388 OPENSSL_EXPORT int RSA_private_encrypt(size_t flen, const uint8_t *from,
389                                        uint8_t *to, RSA *rsa, int padding);
390 
391 // RSA_public_decrypt verifies |flen| bytes of signature from |from| using the
392 // public key in |rsa| and writes the plaintext to |to|. The |to| buffer must
393 // have at least |RSA_size| bytes of space. It returns the number of bytes
394 // written, or -1 on error. The |padding| argument must be one of the
395 // |RSA_*_PADDING| values. If in doubt, |RSA_PKCS1_PADDING| is the most common
396 // but |RSA_PKCS1_PSS_PADDING| (via the |EVP_PKEY| interface) is preferred for
397 // new protocols.
398 //
399 // WARNING: this function is dangerous because it breaks the usual return value
400 // convention. Use |RSA_verify_raw| instead.
401 OPENSSL_EXPORT int RSA_public_decrypt(size_t flen, const uint8_t *from,
402                                       uint8_t *to, RSA *rsa, int padding);
403 
404 
405 // Utility functions.
406 
407 // RSA_size returns the number of bytes in the modulus, which is also the size
408 // of a signature or encrypted value using |rsa|.
409 OPENSSL_EXPORT unsigned RSA_size(const RSA *rsa);
410 
411 // RSA_is_opaque returns one if |rsa| is opaque and doesn't expose its key
412 // material. Otherwise it returns zero.
413 OPENSSL_EXPORT int RSA_is_opaque(const RSA *rsa);
414 
415 // RSAPublicKey_dup allocates a fresh |RSA| and copies the public key from
416 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
417 OPENSSL_EXPORT RSA *RSAPublicKey_dup(const RSA *rsa);
418 
419 // RSAPrivateKey_dup allocates a fresh |RSA| and copies the private key from
420 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
421 OPENSSL_EXPORT RSA *RSAPrivateKey_dup(const RSA *rsa);
422 
423 // RSA_check_key performs basic validity tests on |rsa|. It returns one if
424 // they pass and zero otherwise. Opaque keys and public keys always pass. If it
425 // returns zero then a more detailed error is available on the error queue.
426 OPENSSL_EXPORT int RSA_check_key(const RSA *rsa);
427 
428 // RSA_check_fips performs public key validity tests on |key|. It returns one if
429 // they pass and zero otherwise. Opaque keys always fail. This function does not
430 // mutate |rsa| for thread-safety purposes and may be used concurrently.
431 OPENSSL_EXPORT int RSA_check_fips(RSA *key);
432 
433 // RSA_verify_PKCS1_PSS_mgf1 verifies that |EM| is a correct PSS padding of
434 // |mHash|, where |mHash| is a digest produced by |Hash|. |EM| must point to
435 // exactly |RSA_size(rsa)| bytes of data. The |mgf1Hash| argument specifies the
436 // hash function for generating the mask. If NULL, |Hash| is used. The |sLen|
437 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
438 // the salt length is the same as the hash length. If -2, then the salt length
439 // is recovered and all values accepted.
440 //
441 // If unsure, use -1.
442 //
443 // It returns one on success or zero on error.
444 //
445 // This function implements only the low-level padding logic. Use
446 // |RSA_verify_pss_mgf1| instead.
447 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS_mgf1(const RSA *rsa,
448                                              const uint8_t *mHash,
449                                              const EVP_MD *Hash,
450                                              const EVP_MD *mgf1Hash,
451                                              const uint8_t *EM, int sLen);
452 
453 // RSA_padding_add_PKCS1_PSS_mgf1 writes a PSS padding of |mHash| to |EM|,
454 // where |mHash| is a digest produced by |Hash|. |RSA_size(rsa)| bytes of
455 // output will be written to |EM|. The |mgf1Hash| argument specifies the hash
456 // function for generating the mask. If NULL, |Hash| is used. The |sLen|
457 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
458 // the salt length is the same as the hash length. If -2, then the salt length
459 // is maximal given the space in |EM|.
460 //
461 // It returns one on success or zero on error.
462 //
463 // This function implements only the low-level padding logic. Use
464 // |RSA_sign_pss_mgf1| instead.
465 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS_mgf1(const RSA *rsa, uint8_t *EM,
466                                                   const uint8_t *mHash,
467                                                   const EVP_MD *Hash,
468                                                   const EVP_MD *mgf1Hash,
469                                                   int sLen);
470 
471 // RSA_padding_add_PKCS1_OAEP_mgf1 writes an OAEP padding of |from| to |to|
472 // with the given parameters and hash functions. If |md| is NULL then SHA-1 is
473 // used. If |mgf1md| is NULL then the value of |md| is used (which means SHA-1
474 // if that, in turn, is NULL).
475 //
476 // It returns one on success or zero on error.
477 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP_mgf1(
478     uint8_t *to, size_t to_len, const uint8_t *from, size_t from_len,
479     const uint8_t *param, size_t param_len, const EVP_MD *md,
480     const EVP_MD *mgf1md);
481 
482 // RSA_add_pkcs1_prefix builds a version of |msg| prefixed with the DigestInfo
483 // header for the given hash function and sets |out_msg| to point to it. On
484 // successful return, if |*is_alloced| is one, the caller must release
485 // |*out_msg| with |OPENSSL_free|.
486 OPENSSL_EXPORT int RSA_add_pkcs1_prefix(uint8_t **out_msg, size_t *out_msg_len,
487                                         int *is_alloced, int hash_nid,
488                                         const uint8_t *msg, size_t msg_len);
489 
490 
491 // ASN.1 functions.
492 
493 // RSA_parse_public_key parses a DER-encoded RSAPublicKey structure (RFC 3447)
494 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
495 // error.
496 OPENSSL_EXPORT RSA *RSA_parse_public_key(CBS *cbs);
497 
498 // RSA_public_key_from_bytes parses |in| as a DER-encoded RSAPublicKey structure
499 // (RFC 3447). It returns a newly-allocated |RSA| or NULL on error.
500 OPENSSL_EXPORT RSA *RSA_public_key_from_bytes(const uint8_t *in, size_t in_len);
501 
502 // RSA_marshal_public_key marshals |rsa| as a DER-encoded RSAPublicKey structure
503 // (RFC 3447) and appends the result to |cbb|. It returns one on success and
504 // zero on failure.
505 OPENSSL_EXPORT int RSA_marshal_public_key(CBB *cbb, const RSA *rsa);
506 
507 // RSA_public_key_to_bytes marshals |rsa| as a DER-encoded RSAPublicKey
508 // structure (RFC 3447) and, on success, sets |*out_bytes| to a newly allocated
509 // buffer containing the result and returns one. Otherwise, it returns zero. The
510 // result should be freed with |OPENSSL_free|.
511 OPENSSL_EXPORT int RSA_public_key_to_bytes(uint8_t **out_bytes, size_t *out_len,
512                                            const RSA *rsa);
513 
514 // RSA_parse_private_key parses a DER-encoded RSAPrivateKey structure (RFC 3447)
515 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
516 // error.
517 OPENSSL_EXPORT RSA *RSA_parse_private_key(CBS *cbs);
518 
519 // RSA_private_key_from_bytes parses |in| as a DER-encoded RSAPrivateKey
520 // structure (RFC 3447). It returns a newly-allocated |RSA| or NULL on error.
521 OPENSSL_EXPORT RSA *RSA_private_key_from_bytes(const uint8_t *in,
522                                                size_t in_len);
523 
524 // RSA_marshal_private_key marshals |rsa| as a DER-encoded RSAPrivateKey
525 // structure (RFC 3447) and appends the result to |cbb|. It returns one on
526 // success and zero on failure.
527 OPENSSL_EXPORT int RSA_marshal_private_key(CBB *cbb, const RSA *rsa);
528 
529 // RSA_private_key_to_bytes marshals |rsa| as a DER-encoded RSAPrivateKey
530 // structure (RFC 3447) and, on success, sets |*out_bytes| to a newly allocated
531 // buffer containing the result and returns one. Otherwise, it returns zero. The
532 // result should be freed with |OPENSSL_free|.
533 OPENSSL_EXPORT int RSA_private_key_to_bytes(uint8_t **out_bytes,
534                                             size_t *out_len, const RSA *rsa);
535 
536 
537 // ex_data functions.
538 //
539 // See |ex_data.h| for details.
540 
541 OPENSSL_EXPORT int RSA_get_ex_new_index(long argl, void *argp,
542                                         CRYPTO_EX_unused *unused,
543                                         CRYPTO_EX_dup *dup_unused,
544                                         CRYPTO_EX_free *free_func);
545 OPENSSL_EXPORT int RSA_set_ex_data(RSA *rsa, int idx, void *arg);
546 OPENSSL_EXPORT void *RSA_get_ex_data(const RSA *rsa, int idx);
547 
548 
549 // Flags.
550 
551 // RSA_FLAG_OPAQUE specifies that this RSA_METHOD does not expose its key
552 // material. This may be set if, for instance, it is wrapping some other crypto
553 // API, like a platform key store.
554 #define RSA_FLAG_OPAQUE 1
555 
556 // RSA_FLAG_NO_BLINDING disables blinding of private operations, which is a
557 // dangerous thing to do. It is deprecated and should not be used. It will
558 // be ignored whenever possible.
559 //
560 // This flag must be used if a key without the public exponent |e| is used for
561 // private key operations; avoid using such keys whenever possible.
562 #define RSA_FLAG_NO_BLINDING 8
563 
564 // RSA_FLAG_EXT_PKEY is deprecated and ignored.
565 #define RSA_FLAG_EXT_PKEY 0x20
566 
567 
568 // RSA public exponent values.
569 
570 #define RSA_3 0x3
571 #define RSA_F4 0x10001
572 
573 
574 // Deprecated functions.
575 
576 #define RSA_METHOD_FLAG_NO_CHECK RSA_FLAG_OPAQUE
577 
578 // RSA_flags returns the flags for |rsa|. These are a bitwise OR of |RSA_FLAG_*|
579 // constants.
580 OPENSSL_EXPORT int RSA_flags(const RSA *rsa);
581 
582 // RSA_blinding_on returns one.
583 OPENSSL_EXPORT int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
584 
585 // RSA_generate_key behaves like |RSA_generate_key_ex|, which is what you
586 // should use instead. It returns NULL on error, or a newly-allocated |RSA| on
587 // success. This function is provided for compatibility only. The |callback|
588 // and |cb_arg| parameters must be NULL.
589 OPENSSL_EXPORT RSA *RSA_generate_key(int bits, unsigned long e, void *callback,
590                                      void *cb_arg);
591 
592 // d2i_RSAPublicKey parses an ASN.1, DER-encoded, RSA public key from |len|
593 // bytes at |*inp|. If |out| is not NULL then, on exit, a pointer to the result
594 // is in |*out|. Note that, even if |*out| is already non-NULL on entry, it
595 // will not be written to. Rather, a fresh |RSA| is allocated and the previous
596 // one is freed. On successful exit, |*inp| is advanced past the DER structure.
597 // It returns the result or NULL on error.
598 OPENSSL_EXPORT RSA *d2i_RSAPublicKey(RSA **out, const uint8_t **inp, long len);
599 
600 // i2d_RSAPublicKey marshals |in| to an ASN.1, DER structure. If |outp| is not
601 // NULL then the result is written to |*outp| and |*outp| is advanced just past
602 // the output. It returns the number of bytes in the result, whether written or
603 // not, or a negative value on error.
604 OPENSSL_EXPORT int i2d_RSAPublicKey(const RSA *in, uint8_t **outp);
605 
606 // d2i_RSAPrivateKey parses an ASN.1, DER-encoded, RSA private key from |len|
607 // bytes at |*inp|. If |out| is not NULL then, on exit, a pointer to the result
608 // is in |*out|. Note that, even if |*out| is already non-NULL on entry, it
609 // will not be written to. Rather, a fresh |RSA| is allocated and the previous
610 // one is freed. On successful exit, |*inp| is advanced past the DER structure.
611 // It returns the result or NULL on error.
612 OPENSSL_EXPORT RSA *d2i_RSAPrivateKey(RSA **out, const uint8_t **inp, long len);
613 
614 // i2d_RSAPrivateKey marshals |in| to an ASN.1, DER structure. If |outp| is not
615 // NULL then the result is written to |*outp| and |*outp| is advanced just past
616 // the output. It returns the number of bytes in the result, whether written or
617 // not, or a negative value on error.
618 OPENSSL_EXPORT int i2d_RSAPrivateKey(const RSA *in, uint8_t **outp);
619 
620 // RSA_padding_add_PKCS1_PSS acts like |RSA_padding_add_PKCS1_PSS_mgf1| but the
621 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
622 //
623 // This function implements only the low-level padding logic. Use
624 // |RSA_sign_pss_mgf1| instead.
625 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS(const RSA *rsa, uint8_t *EM,
626                                              const uint8_t *mHash,
627                                              const EVP_MD *Hash, int sLen);
628 
629 // RSA_verify_PKCS1_PSS acts like |RSA_verify_PKCS1_PSS_mgf1| but the
630 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
631 //
632 // This function implements only the low-level padding logic. Use
633 // |RSA_verify_pss_mgf1| instead.
634 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS(const RSA *rsa, const uint8_t *mHash,
635                                         const EVP_MD *Hash, const uint8_t *EM,
636                                         int sLen);
637 
638 // RSA_padding_add_PKCS1_OAEP acts like |RSA_padding_add_PKCS1_OAEP_mgf1| but
639 // the |md| and |mgf1md| parameters of the latter are implicitly set to NULL,
640 // which means SHA-1.
641 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP(uint8_t *to, size_t to_len,
642                                               const uint8_t *from,
643                                               size_t from_len,
644                                               const uint8_t *param,
645                                               size_t param_len);
646 
647 // RSA_print prints a textual representation of |rsa| to |bio|. It returns one
648 // on success or zero otherwise.
649 OPENSSL_EXPORT int RSA_print(BIO *bio, const RSA *rsa, int indent);
650 
651 
652 struct rsa_meth_st {
653   struct openssl_method_common_st common;
654 
655   void *app_data;
656 
657   int (*init)(RSA *rsa);
658   int (*finish)(RSA *rsa);
659 
660   // size returns the size of the RSA modulus in bytes.
661   size_t (*size)(const RSA *rsa);
662 
663   int (*sign)(int type, const uint8_t *m, unsigned int m_length,
664               uint8_t *sigret, unsigned int *siglen, const RSA *rsa);
665 
666   // These functions mirror the |RSA_*| functions of the same name.
667   int (*sign_raw)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
668                   const uint8_t *in, size_t in_len, int padding);
669   int (*decrypt)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
670                  const uint8_t *in, size_t in_len, int padding);
671 
672   // private_transform takes a big-endian integer from |in|, calculates the
673   // d'th power of it, modulo the RSA modulus and writes the result as a
674   // big-endian integer to |out|. Both |in| and |out| are |len| bytes long and
675   // |len| is always equal to |RSA_size(rsa)|. If the result of the transform
676   // can be represented in fewer than |len| bytes, then |out| must be zero
677   // padded on the left.
678   //
679   // It returns one on success and zero otherwise.
680   //
681   // RSA decrypt and sign operations will call this, thus an ENGINE might wish
682   // to override it in order to avoid having to implement the padding
683   // functionality demanded by those, higher level, operations.
684   int (*private_transform)(RSA *rsa, uint8_t *out, const uint8_t *in,
685                            size_t len);
686 
687   int flags;
688 };
689 
690 
691 // Private functions.
692 
693 typedef struct bn_blinding_st BN_BLINDING;
694 
695 struct rsa_st {
696   RSA_METHOD *meth;
697 
698   // Access to the following fields was historically allowed, but
699   // deprecated. Use |RSA_get0_*| and |RSA_set0_*| instead. Access to all other
700   // fields is forbidden and will cause threading errors.
701   BIGNUM *n;
702   BIGNUM *e;
703   BIGNUM *d;
704   BIGNUM *p;
705   BIGNUM *q;
706   BIGNUM *dmp1;
707   BIGNUM *dmq1;
708   BIGNUM *iqmp;
709 
710   // be careful using this if the RSA structure is shared
711   CRYPTO_EX_DATA ex_data;
712   CRYPTO_refcount_t references;
713   int flags;
714 
715   CRYPTO_MUTEX lock;
716 
717   // Used to cache montgomery values. The creation of these values is protected
718   // by |lock|.
719   BN_MONT_CTX *mont_n;
720   BN_MONT_CTX *mont_p;
721   BN_MONT_CTX *mont_q;
722 
723   // The following fields are copies of |d|, |dmp1|, and |dmq1|, respectively,
724   // but with the correct widths to prevent side channels. These must use
725   // separate copies due to threading concerns caused by OpenSSL's API
726   // mistakes. See https://github.com/openssl/openssl/issues/5158 and
727   // the |freeze_private_key| implementation.
728   BIGNUM *d_fixed, *dmp1_fixed, *dmq1_fixed;
729 
730   // inv_small_mod_large_mont is q^-1 mod p in Montgomery form, using |mont_p|,
731   // if |p| >= |q|. Otherwise, it is p^-1 mod q in Montgomery form, using
732   // |mont_q|.
733   BIGNUM *inv_small_mod_large_mont;
734 
735   // num_blindings contains the size of the |blindings| and |blindings_inuse|
736   // arrays. This member and the |blindings_inuse| array are protected by
737   // |lock|.
738   unsigned num_blindings;
739   // blindings is an array of BN_BLINDING structures that can be reserved by a
740   // thread by locking |lock| and changing the corresponding element in
741   // |blindings_inuse| from 0 to 1.
742   BN_BLINDING **blindings;
743   unsigned char *blindings_inuse;
744   uint64_t blinding_fork_generation;
745 
746   // private_key_frozen is one if the key has been used for a private key
747   // operation and may no longer be mutated.
748   unsigned private_key_frozen:1;
749 };
750 
751 
752 #if defined(__cplusplus)
753 }  // extern C
754 
755 extern "C++" {
756 
757 BSSL_NAMESPACE_BEGIN
758 
759 BORINGSSL_MAKE_DELETER(RSA, RSA_free)
760 BORINGSSL_MAKE_UP_REF(RSA, RSA_up_ref)
761 
762 BSSL_NAMESPACE_END
763 
764 }  // extern C++
765 
766 #endif
767 
768 #define RSA_R_BAD_ENCODING 100
769 #define RSA_R_BAD_E_VALUE 101
770 #define RSA_R_BAD_FIXED_HEADER_DECRYPT 102
771 #define RSA_R_BAD_PAD_BYTE_COUNT 103
772 #define RSA_R_BAD_RSA_PARAMETERS 104
773 #define RSA_R_BAD_SIGNATURE 105
774 #define RSA_R_BAD_VERSION 106
775 #define RSA_R_BLOCK_TYPE_IS_NOT_01 107
776 #define RSA_R_BN_NOT_INITIALIZED 108
777 #define RSA_R_CANNOT_RECOVER_MULTI_PRIME_KEY 109
778 #define RSA_R_CRT_PARAMS_ALREADY_GIVEN 110
779 #define RSA_R_CRT_VALUES_INCORRECT 111
780 #define RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN 112
781 #define RSA_R_DATA_TOO_LARGE 113
782 #define RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE 114
783 #define RSA_R_DATA_TOO_LARGE_FOR_MODULUS 115
784 #define RSA_R_DATA_TOO_SMALL 116
785 #define RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE 117
786 #define RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY 118
787 #define RSA_R_D_E_NOT_CONGRUENT_TO_1 119
788 #define RSA_R_EMPTY_PUBLIC_KEY 120
789 #define RSA_R_ENCODE_ERROR 121
790 #define RSA_R_FIRST_OCTET_INVALID 122
791 #define RSA_R_INCONSISTENT_SET_OF_CRT_VALUES 123
792 #define RSA_R_INTERNAL_ERROR 124
793 #define RSA_R_INVALID_MESSAGE_LENGTH 125
794 #define RSA_R_KEY_SIZE_TOO_SMALL 126
795 #define RSA_R_LAST_OCTET_INVALID 127
796 #define RSA_R_MODULUS_TOO_LARGE 128
797 #define RSA_R_MUST_HAVE_AT_LEAST_TWO_PRIMES 129
798 #define RSA_R_NO_PUBLIC_EXPONENT 130
799 #define RSA_R_NULL_BEFORE_BLOCK_MISSING 131
800 #define RSA_R_N_NOT_EQUAL_P_Q 132
801 #define RSA_R_OAEP_DECODING_ERROR 133
802 #define RSA_R_ONLY_ONE_OF_P_Q_GIVEN 134
803 #define RSA_R_OUTPUT_BUFFER_TOO_SMALL 135
804 #define RSA_R_PADDING_CHECK_FAILED 136
805 #define RSA_R_PKCS_DECODING_ERROR 137
806 #define RSA_R_SLEN_CHECK_FAILED 138
807 #define RSA_R_SLEN_RECOVERY_FAILED 139
808 #define RSA_R_TOO_LONG 140
809 #define RSA_R_TOO_MANY_ITERATIONS 141
810 #define RSA_R_UNKNOWN_ALGORITHM_TYPE 142
811 #define RSA_R_UNKNOWN_PADDING_TYPE 143
812 #define RSA_R_VALUE_MISSING 144
813 #define RSA_R_WRONG_SIGNATURE_LENGTH 145
814 #define RSA_R_PUBLIC_KEY_VALIDATION_FAILED 146
815 #define RSA_R_D_OUT_OF_RANGE 147
816 #define RSA_R_BLOCK_TYPE_IS_NOT_02 148
817 
818 #endif  // OPENSSL_HEADER_RSA_H
819