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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_public_key returns a new |RSA| object containing a public key with
83 // the specified parameters, or NULL on error or invalid input.
84 OPENSSL_EXPORT RSA *RSA_new_public_key(const BIGNUM *n, const BIGNUM *e);
85 
86 // RSA_new_private_key returns a new |RSA| object containing a private key with
87 // the specified parameters, or NULL on error or invalid input. All parameters
88 // are mandatory and may not be NULL.
89 //
90 // This function creates standard RSA private keys with CRT parameters.
91 OPENSSL_EXPORT RSA *RSA_new_private_key(const BIGNUM *n, const BIGNUM *e,
92                                         const BIGNUM *d, const BIGNUM *p,
93                                         const BIGNUM *q, const BIGNUM *dmp1,
94                                         const BIGNUM *dmq1, const BIGNUM *iqmp);
95 
96 // RSA_new returns a new, empty |RSA| object or NULL on error. Prefer using
97 // |RSA_new_public_key| or |RSA_new_private_key| to import an RSA key.
98 OPENSSL_EXPORT RSA *RSA_new(void);
99 
100 // RSA_new_method acts the same as |RSA_new| but takes an explicit |ENGINE|.
101 OPENSSL_EXPORT RSA *RSA_new_method(const ENGINE *engine);
102 
103 // RSA_free decrements the reference count of |rsa| and frees it if the
104 // reference count drops to zero.
105 OPENSSL_EXPORT void RSA_free(RSA *rsa);
106 
107 // RSA_up_ref increments the reference count of |rsa| and returns one. It does
108 // not mutate |rsa| for thread-safety purposes and may be used concurrently.
109 OPENSSL_EXPORT int RSA_up_ref(RSA *rsa);
110 
111 
112 // Properties.
113 
114 // OPENSSL_RSA_MAX_MODULUS_BITS is the maximum supported RSA modulus, in bits.
115 //
116 // TODO(davidben): Reduce this to 8192.
117 #define OPENSSL_RSA_MAX_MODULUS_BITS 16384
118 
119 // RSA_bits returns the size of |rsa|, in bits.
120 OPENSSL_EXPORT unsigned RSA_bits(const RSA *rsa);
121 
122 // RSA_get0_n returns |rsa|'s public modulus.
123 OPENSSL_EXPORT const BIGNUM *RSA_get0_n(const RSA *rsa);
124 
125 // RSA_get0_e returns |rsa|'s public exponent.
126 OPENSSL_EXPORT const BIGNUM *RSA_get0_e(const RSA *rsa);
127 
128 // RSA_get0_d returns |rsa|'s private exponent. If |rsa| is a public key, this
129 // value will be NULL.
130 OPENSSL_EXPORT const BIGNUM *RSA_get0_d(const RSA *rsa);
131 
132 // RSA_get0_p returns |rsa|'s first private prime factor. If |rsa| is a public
133 // key or lacks its prime factors, this value will be NULL.
134 OPENSSL_EXPORT const BIGNUM *RSA_get0_p(const RSA *rsa);
135 
136 // RSA_get0_q returns |rsa|'s second private prime factor. If |rsa| is a public
137 // key or lacks its prime factors, this value will be NULL.
138 OPENSSL_EXPORT const BIGNUM *RSA_get0_q(const RSA *rsa);
139 
140 // RSA_get0_dmp1 returns d (mod p-1) for |rsa|. If |rsa| is a public key or
141 // lacks CRT parameters, this value will be NULL.
142 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmp1(const RSA *rsa);
143 
144 // RSA_get0_dmq1 returns d (mod q-1) for |rsa|. If |rsa| is a public key or
145 // lacks CRT parameters, this value will be NULL.
146 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmq1(const RSA *rsa);
147 
148 // RSA_get0_iqmp returns q^-1 (mod p). If |rsa| is a public key or lacks CRT
149 // parameters, this value will be NULL.
150 OPENSSL_EXPORT const BIGNUM *RSA_get0_iqmp(const RSA *rsa);
151 
152 // RSA_get0_key sets |*out_n|, |*out_e|, and |*out_d|, if non-NULL, to |rsa|'s
153 // modulus, public exponent, and private exponent, respectively. If |rsa| is a
154 // public key, the private exponent will be set to NULL.
155 OPENSSL_EXPORT void RSA_get0_key(const RSA *rsa, const BIGNUM **out_n,
156                                  const BIGNUM **out_e, const BIGNUM **out_d);
157 
158 // RSA_get0_factors sets |*out_p| and |*out_q|, if non-NULL, to |rsa|'s prime
159 // factors. If |rsa| is a public key, they will be set to NULL.
160 OPENSSL_EXPORT void RSA_get0_factors(const RSA *rsa, const BIGNUM **out_p,
161                                      const BIGNUM **out_q);
162 
163 // RSA_get0_crt_params sets |*out_dmp1|, |*out_dmq1|, and |*out_iqmp|, if
164 // non-NULL, to |rsa|'s CRT parameters. These are d (mod p-1), d (mod q-1) and
165 // q^-1 (mod p), respectively. If |rsa| is a public key, each parameter will be
166 // set to NULL.
167 OPENSSL_EXPORT void RSA_get0_crt_params(const RSA *rsa, const BIGNUM **out_dmp1,
168                                         const BIGNUM **out_dmq1,
169                                         const BIGNUM **out_iqmp);
170 
171 
172 // Setting individual properties.
173 //
174 // These functions allow setting individual properties of an |RSA| object. This
175 // is typically used with |RSA_new| to construct an RSA key field by field.
176 // Prefer instead to use |RSA_new_public_key| and |RSA_new_private_key|. These
177 // functions defer some initialization to the first use of an |RSA| object. This
178 // means invalid inputs may be caught late.
179 //
180 // TODO(crbug.com/boringssl/316): This deferred initialization also causes
181 // performance problems in multi-threaded applications. The preferred APIs
182 // currently have the same issues, but they will initialize eagerly in the
183 // future.
184 
185 // RSA_set0_key sets |rsa|'s modulus, public exponent, and private exponent to
186 // |n|, |e|, and |d| respectively, if non-NULL. On success, it takes ownership
187 // of each argument and returns one. Otherwise, it returns zero.
188 //
189 // |d| may be NULL, but |n| and |e| must either be non-NULL or already
190 // configured on |rsa|.
191 //
192 // It is an error to call this function after |rsa| has been used for a
193 // cryptographic operation. Construct a new |RSA| object instead.
194 OPENSSL_EXPORT int RSA_set0_key(RSA *rsa, BIGNUM *n, BIGNUM *e, BIGNUM *d);
195 
196 // RSA_set0_factors sets |rsa|'s prime factors to |p| and |q|, if non-NULL, and
197 // takes ownership of them. On success, it takes ownership of each argument and
198 // returns one. Otherwise, it returns zero.
199 //
200 // Each argument must either be non-NULL or already configured on |rsa|.
201 //
202 // It is an error to call this function after |rsa| has been used for a
203 // cryptographic operation. Construct a new |RSA| object instead.
204 OPENSSL_EXPORT int RSA_set0_factors(RSA *rsa, BIGNUM *p, BIGNUM *q);
205 
206 // RSA_set0_crt_params sets |rsa|'s CRT parameters to |dmp1|, |dmq1|, and
207 // |iqmp|, if non-NULL, and takes ownership of them. On success, it takes
208 // ownership of its parameters and returns one. Otherwise, it returns zero.
209 //
210 // Each argument must either be non-NULL or already configured on |rsa|.
211 //
212 // It is an error to call this function after |rsa| has been used for a
213 // cryptographic operation. Construct a new |RSA| object instead.
214 OPENSSL_EXPORT int RSA_set0_crt_params(RSA *rsa, BIGNUM *dmp1, BIGNUM *dmq1,
215                                        BIGNUM *iqmp);
216 
217 
218 // Key generation.
219 
220 // RSA_generate_key_ex generates a new RSA key where the modulus has size
221 // |bits| and the public exponent is |e|. If unsure, |RSA_F4| is a good value
222 // for |e|. If |cb| is not NULL then it is called during the key generation
223 // process. In addition to the calls documented for |BN_generate_prime_ex|, it
224 // is called with event=2 when the n'th prime is rejected as unsuitable and
225 // with event=3 when a suitable value for |p| is found.
226 //
227 // It returns one on success or zero on error.
228 OPENSSL_EXPORT int RSA_generate_key_ex(RSA *rsa, int bits, const BIGNUM *e,
229                                        BN_GENCB *cb);
230 
231 // RSA_generate_key_fips behaves like |RSA_generate_key_ex| but performs
232 // additional checks for FIPS compliance. The public exponent is always 65537
233 // and |bits| must be either 2048 or 3072.
234 OPENSSL_EXPORT int RSA_generate_key_fips(RSA *rsa, int bits, BN_GENCB *cb);
235 
236 
237 // Encryption / Decryption
238 //
239 // These functions are considered non-mutating for thread-safety purposes and
240 // may be used concurrently.
241 
242 // RSA_PKCS1_PADDING denotes PKCS#1 v1.5 padding. When used with encryption,
243 // this is RSAES-PKCS1-v1_5. When used with signing, this is RSASSA-PKCS1-v1_5.
244 //
245 // WARNING: The RSAES-PKCS1-v1_5 encryption scheme is vulnerable to a
246 // chosen-ciphertext attack. Decrypting attacker-supplied ciphertext with
247 // RSAES-PKCS1-v1_5 may give the attacker control over your private key. This
248 // does not impact the RSASSA-PKCS1-v1_5 signature scheme. See "Chosen
249 // Ciphertext Attacks Against Protocols Based on the RSA Encryption Standard
250 // PKCS #1", Daniel Bleichenbacher, Advances in Cryptology (Crypto '98).
251 #define RSA_PKCS1_PADDING 1
252 
253 // RSA_NO_PADDING denotes a raw RSA operation.
254 #define RSA_NO_PADDING 3
255 
256 // RSA_PKCS1_OAEP_PADDING denotes the RSAES-OAEP encryption scheme.
257 #define RSA_PKCS1_OAEP_PADDING 4
258 
259 // RSA_PKCS1_PSS_PADDING denotes the RSASSA-PSS signature scheme. This value may
260 // not be passed into |RSA_sign_raw|, only |EVP_PKEY_CTX_set_rsa_padding|. See
261 // also |RSA_sign_pss_mgf1| and |RSA_verify_pss_mgf1|.
262 #define RSA_PKCS1_PSS_PADDING 6
263 
264 // RSA_encrypt encrypts |in_len| bytes from |in| to the public key from |rsa|
265 // and writes, at most, |max_out| bytes of encrypted data to |out|. The
266 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
267 //
268 // It returns 1 on success or zero on error.
269 //
270 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
271 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
272 OPENSSL_EXPORT int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out,
273                                size_t max_out, const uint8_t *in, size_t in_len,
274                                int padding);
275 
276 // RSA_decrypt decrypts |in_len| bytes from |in| with the private key from
277 // |rsa| and writes, at most, |max_out| bytes of plaintext to |out|. The
278 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
279 //
280 // It returns 1 on success or zero on error.
281 //
282 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
283 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
284 //
285 // WARNING: Passing |RSA_PKCS1_PADDING| into this function is deprecated and
286 // insecure. RSAES-PKCS1-v1_5 is vulnerable to a chosen-ciphertext attack.
287 // Decrypting attacker-supplied ciphertext with RSAES-PKCS1-v1_5 may give the
288 // attacker control over your private key. See "Chosen Ciphertext Attacks
289 // Against Protocols Based on the RSA Encryption Standard PKCS #1", Daniel
290 // Bleichenbacher, Advances in Cryptology (Crypto '98).
291 //
292 // In some limited cases, such as TLS RSA key exchange, it is possible to
293 // mitigate this flaw with custom, protocol-specific padding logic. This
294 // should be implemented with |RSA_NO_PADDING|, not |RSA_PKCS1_PADDING|.
295 OPENSSL_EXPORT int RSA_decrypt(RSA *rsa, size_t *out_len, uint8_t *out,
296                                size_t max_out, const uint8_t *in, size_t in_len,
297                                int padding);
298 
299 // RSA_public_encrypt encrypts |flen| bytes from |from| to the public key in
300 // |rsa| and writes the encrypted data to |to|. The |to| buffer must have at
301 // least |RSA_size| bytes of space. It returns the number of bytes written, or
302 // -1 on error. The |padding| argument must be one of the |RSA_*_PADDING|
303 // values. If in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
304 //
305 // WARNING: this function is dangerous because it breaks the usual return value
306 // convention. Use |RSA_encrypt| instead.
307 OPENSSL_EXPORT int RSA_public_encrypt(size_t flen, const uint8_t *from,
308                                       uint8_t *to, RSA *rsa, int padding);
309 
310 // RSA_private_decrypt decrypts |flen| bytes from |from| with the public key in
311 // |rsa| and writes the plaintext to |to|. The |to| buffer must have at least
312 // |RSA_size| bytes of space. It returns the number of bytes written, or -1 on
313 // error. The |padding| argument must be one of the |RSA_*_PADDING| values. If
314 // in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols. Passing
315 // |RSA_PKCS1_PADDING| into this function is deprecated and insecure. See
316 // |RSA_decrypt|.
317 //
318 // WARNING: this function is dangerous because it breaks the usual return value
319 // convention. Use |RSA_decrypt| instead.
320 OPENSSL_EXPORT int RSA_private_decrypt(size_t flen, const uint8_t *from,
321                                        uint8_t *to, RSA *rsa, int padding);
322 
323 
324 // Signing / Verification
325 //
326 // These functions are considered non-mutating for thread-safety purposes and
327 // may be used concurrently.
328 
329 // RSA_sign signs |digest_len| bytes of digest from |digest| with |rsa| using
330 // RSASSA-PKCS1-v1_5. It writes, at most, |RSA_size(rsa)| bytes to |out|. On
331 // successful return, the actual number of bytes written is written to
332 // |*out_len|.
333 //
334 // The |hash_nid| argument identifies the hash function used to calculate
335 // |digest| and is embedded in the resulting signature. For example, it might be
336 // |NID_sha256|.
337 //
338 // It returns 1 on success and zero on error.
339 //
340 // WARNING: |digest| must be the result of hashing the data to be signed with
341 // |hash_nid|. Passing unhashed inputs will not result in a secure signature
342 // scheme.
343 OPENSSL_EXPORT int RSA_sign(int hash_nid, const uint8_t *digest,
344                             size_t digest_len, uint8_t *out, unsigned *out_len,
345                             RSA *rsa);
346 
347 // RSA_sign_pss_mgf1 signs |digest_len| bytes from |digest| with the public key
348 // from |rsa| using RSASSA-PSS with MGF1 as the mask generation function. It
349 // writes, at most, |max_out| bytes of signature data to |out|. The |max_out|
350 // argument must be, at least, |RSA_size| in order to ensure success. It returns
351 // 1 on success or zero on error.
352 //
353 // The |md| and |mgf1_md| arguments identify the hash used to calculate |digest|
354 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
355 // used.
356 //
357 // |salt_len| specifies the expected salt length in bytes. If |salt_len| is -1,
358 // then the salt length is the same as the hash length. If -2, then the salt
359 // length is maximal given the size of |rsa|. If unsure, use -1.
360 //
361 // WARNING: |digest| must be the result of hashing the data to be signed with
362 // |md|. Passing unhashed inputs will not result in a secure signature scheme.
363 OPENSSL_EXPORT int RSA_sign_pss_mgf1(RSA *rsa, size_t *out_len, uint8_t *out,
364                                      size_t max_out, const uint8_t *digest,
365                                      size_t digest_len, const EVP_MD *md,
366                                      const EVP_MD *mgf1_md, int salt_len);
367 
368 // RSA_sign_raw performs the private key portion of computing a signature with
369 // |rsa|. It writes, at most, |max_out| bytes of signature data to |out|. The
370 // |max_out| argument must be, at least, |RSA_size| in order to ensure the
371 // output fits. It returns 1 on success or zero on error.
372 //
373 // If |padding| is |RSA_PKCS1_PADDING|, this function wraps |in| with the
374 // padding portion of RSASSA-PKCS1-v1_5 and then performs the raw private key
375 // operation. The caller is responsible for hashing the input and wrapping it in
376 // a DigestInfo structure.
377 //
378 // If |padding| is |RSA_NO_PADDING|, this function only performs the raw private
379 // key operation, interpreting |in| as a integer modulo n. The caller is
380 // responsible for hashing the input and encoding it for the signature scheme
381 // being implemented.
382 //
383 // WARNING: This function is a building block for a signature scheme, not a
384 // complete one. |in| must be the result of hashing and encoding the data as
385 // needed for the scheme being implemented. Passing in arbitrary inputs will not
386 // result in a secure signature scheme.
387 OPENSSL_EXPORT int RSA_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out,
388                                 size_t max_out, const uint8_t *in,
389                                 size_t in_len, int padding);
390 
391 // RSA_verify verifies that |sig_len| bytes from |sig| are a valid,
392 // RSASSA-PKCS1-v1_5 signature of |digest_len| bytes at |digest| by |rsa|.
393 //
394 // The |hash_nid| argument identifies the hash function used to calculate
395 // |digest| and is embedded in the resulting signature in order to prevent hash
396 // confusion attacks. For example, it might be |NID_sha256|.
397 //
398 // It returns one if the signature is valid and zero otherwise.
399 //
400 // WARNING: this differs from the original, OpenSSL function which additionally
401 // returned -1 on error.
402 //
403 // WARNING: |digest| must be the result of hashing the data to be verified with
404 // |hash_nid|. Passing unhashed input will not result in a secure signature
405 // scheme.
406 OPENSSL_EXPORT int RSA_verify(int hash_nid, const uint8_t *digest,
407                               size_t digest_len, const uint8_t *sig,
408                               size_t sig_len, RSA *rsa);
409 
410 // RSA_verify_pss_mgf1 verifies that |sig_len| bytes from |sig| are a valid,
411 // RSASSA-PSS signature of |digest_len| bytes at |digest| by |rsa|. It returns
412 // one if the signature is valid and zero otherwise. MGF1 is used as the mask
413 // generation function.
414 //
415 // The |md| and |mgf1_md| arguments identify the hash used to calculate |digest|
416 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
417 // used. |salt_len| specifies the expected salt length in bytes.
418 //
419 // If |salt_len| is -1, then the salt length is the same as the hash length. If
420 // -2, then the salt length is recovered and all values accepted. If unsure, use
421 // -1.
422 //
423 // WARNING: |digest| must be the result of hashing the data to be verified with
424 // |md|. Passing unhashed input will not result in a secure signature scheme.
425 OPENSSL_EXPORT int RSA_verify_pss_mgf1(RSA *rsa, const uint8_t *digest,
426                                        size_t digest_len, const EVP_MD *md,
427                                        const EVP_MD *mgf1_md, int salt_len,
428                                        const uint8_t *sig, size_t sig_len);
429 
430 // RSA_verify_raw performs the public key portion of verifying |in_len| bytes of
431 // signature from |in| using the public key from |rsa|. On success, it returns
432 // one and writes, at most, |max_out| bytes of output to |out|. The |max_out|
433 // argument must be, at least, |RSA_size| in order to ensure the output fits. On
434 // failure or invalid input, it returns zero.
435 //
436 // If |padding| is |RSA_PKCS1_PADDING|, this function checks the padding portion
437 // of RSASSA-PKCS1-v1_5 and outputs the remainder of the encoded digest. The
438 // caller is responsible for checking the output is a DigestInfo-wrapped digest
439 // of the message.
440 //
441 // If |padding| is |RSA_NO_PADDING|, this function only performs the raw public
442 // key operation. The caller is responsible for checking the output is a valid
443 // result for the signature scheme being implemented.
444 //
445 // WARNING: This function is a building block for a signature scheme, not a
446 // complete one. Checking for arbitrary strings in |out| will not result in a
447 // secure signature scheme.
448 OPENSSL_EXPORT int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out,
449                                   size_t max_out, const uint8_t *in,
450                                   size_t in_len, int padding);
451 
452 // RSA_private_encrypt performs the private key portion of computing a signature
453 // with |rsa|. It takes |flen| bytes from |from| as input and writes the result
454 // to |to|. The |to| buffer must have at least |RSA_size| bytes of space. It
455 // returns the number of bytes written, or -1 on error.
456 //
457 // For the interpretation of |padding| and the input, see |RSA_sign_raw|.
458 //
459 // WARNING: This function is a building block for a signature scheme, not a
460 // complete one. See |RSA_sign_raw| for details.
461 //
462 // WARNING: This function is dangerous because it breaks the usual return value
463 // convention. Use |RSA_sign_raw| instead.
464 OPENSSL_EXPORT int RSA_private_encrypt(size_t flen, const uint8_t *from,
465                                        uint8_t *to, RSA *rsa, int padding);
466 
467 // RSA_public_decrypt performs the public key portion of verifying |flen| bytes
468 // of signature from |from| using the public key from |rsa|. It writes the
469 // result to |to|, which must have at least |RSA_size| bytes of space. It
470 // returns the number of bytes written, or -1 on error.
471 //
472 // For the interpretation of |padding| and the result, see |RSA_verify_raw|.
473 //
474 // WARNING: This function is a building block for a signature scheme, not a
475 // complete one. See |RSA_verify_raw| for details.
476 //
477 // WARNING: This function is dangerous because it breaks the usual return value
478 // convention. Use |RSA_verify_raw| instead.
479 OPENSSL_EXPORT int RSA_public_decrypt(size_t flen, const uint8_t *from,
480                                       uint8_t *to, RSA *rsa, int padding);
481 
482 
483 // Utility functions.
484 
485 // RSA_size returns the number of bytes in the modulus, which is also the size
486 // of a signature or encrypted value using |rsa|.
487 OPENSSL_EXPORT unsigned RSA_size(const RSA *rsa);
488 
489 // RSA_is_opaque returns one if |rsa| is opaque and doesn't expose its key
490 // material. Otherwise it returns zero.
491 OPENSSL_EXPORT int RSA_is_opaque(const RSA *rsa);
492 
493 // RSAPublicKey_dup allocates a fresh |RSA| and copies the public key from
494 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
495 OPENSSL_EXPORT RSA *RSAPublicKey_dup(const RSA *rsa);
496 
497 // RSAPrivateKey_dup allocates a fresh |RSA| and copies the private key from
498 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
499 OPENSSL_EXPORT RSA *RSAPrivateKey_dup(const RSA *rsa);
500 
501 // RSA_check_key performs basic validity tests on |rsa|. It returns one if
502 // they pass and zero otherwise. Opaque keys and public keys always pass. If it
503 // returns zero then a more detailed error is available on the error queue.
504 OPENSSL_EXPORT int RSA_check_key(const RSA *rsa);
505 
506 // RSA_check_fips performs public key validity tests on |key|. It returns one if
507 // they pass and zero otherwise. Opaque keys always fail. This function does not
508 // mutate |rsa| for thread-safety purposes and may be used concurrently.
509 OPENSSL_EXPORT int RSA_check_fips(RSA *key);
510 
511 // RSA_verify_PKCS1_PSS_mgf1 verifies that |EM| is a correct PSS padding of
512 // |mHash|, where |mHash| is a digest produced by |Hash|. |EM| must point to
513 // exactly |RSA_size(rsa)| bytes of data. The |mgf1Hash| argument specifies the
514 // hash function for generating the mask. If NULL, |Hash| is used. The |sLen|
515 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
516 // the salt length is the same as the hash length. If -2, then the salt length
517 // is recovered and all values accepted.
518 //
519 // If unsure, use -1.
520 //
521 // It returns one on success or zero on error.
522 //
523 // This function implements only the low-level padding logic. Use
524 // |RSA_verify_pss_mgf1| instead.
525 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS_mgf1(const RSA *rsa,
526                                              const uint8_t *mHash,
527                                              const EVP_MD *Hash,
528                                              const EVP_MD *mgf1Hash,
529                                              const uint8_t *EM, int sLen);
530 
531 // RSA_padding_add_PKCS1_PSS_mgf1 writes a PSS padding of |mHash| to |EM|,
532 // where |mHash| is a digest produced by |Hash|. |RSA_size(rsa)| bytes of
533 // output will be written to |EM|. The |mgf1Hash| argument specifies the hash
534 // function for generating the mask. If NULL, |Hash| is used. The |sLen|
535 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
536 // the salt length is the same as the hash length. If -2, then the salt length
537 // is maximal given the space in |EM|.
538 //
539 // It returns one on success or zero on error.
540 //
541 // This function implements only the low-level padding logic. Use
542 // |RSA_sign_pss_mgf1| instead.
543 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS_mgf1(const RSA *rsa, uint8_t *EM,
544                                                   const uint8_t *mHash,
545                                                   const EVP_MD *Hash,
546                                                   const EVP_MD *mgf1Hash,
547                                                   int sLen);
548 
549 // RSA_padding_add_PKCS1_OAEP_mgf1 writes an OAEP padding of |from| to |to|
550 // with the given parameters and hash functions. If |md| is NULL then SHA-1 is
551 // used. If |mgf1md| is NULL then the value of |md| is used (which means SHA-1
552 // if that, in turn, is NULL).
553 //
554 // It returns one on success or zero on error.
555 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP_mgf1(
556     uint8_t *to, size_t to_len, const uint8_t *from, size_t from_len,
557     const uint8_t *param, size_t param_len, const EVP_MD *md,
558     const EVP_MD *mgf1md);
559 
560 // RSA_add_pkcs1_prefix builds a version of |digest| prefixed with the
561 // DigestInfo header for the given hash function and sets |out_msg| to point to
562 // it. On successful return, if |*is_alloced| is one, the caller must release
563 // |*out_msg| with |OPENSSL_free|.
564 OPENSSL_EXPORT int RSA_add_pkcs1_prefix(uint8_t **out_msg, size_t *out_msg_len,
565                                         int *is_alloced, int hash_nid,
566                                         const uint8_t *digest,
567                                         size_t digest_len);
568 
569 
570 // ASN.1 functions.
571 
572 // RSA_parse_public_key parses a DER-encoded RSAPublicKey structure (RFC 8017)
573 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
574 // error.
575 OPENSSL_EXPORT RSA *RSA_parse_public_key(CBS *cbs);
576 
577 // RSA_public_key_from_bytes parses |in| as a DER-encoded RSAPublicKey structure
578 // (RFC 8017). It returns a newly-allocated |RSA| or NULL on error.
579 OPENSSL_EXPORT RSA *RSA_public_key_from_bytes(const uint8_t *in, size_t in_len);
580 
581 // RSA_marshal_public_key marshals |rsa| as a DER-encoded RSAPublicKey structure
582 // (RFC 8017) and appends the result to |cbb|. It returns one on success and
583 // zero on failure.
584 OPENSSL_EXPORT int RSA_marshal_public_key(CBB *cbb, const RSA *rsa);
585 
586 // RSA_public_key_to_bytes marshals |rsa| as a DER-encoded RSAPublicKey
587 // structure (RFC 8017) and, on success, sets |*out_bytes| to a newly allocated
588 // buffer containing the result and returns one. Otherwise, it returns zero. The
589 // result should be freed with |OPENSSL_free|.
590 OPENSSL_EXPORT int RSA_public_key_to_bytes(uint8_t **out_bytes, size_t *out_len,
591                                            const RSA *rsa);
592 
593 // RSA_parse_private_key parses a DER-encoded RSAPrivateKey structure (RFC 8017)
594 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
595 // error.
596 OPENSSL_EXPORT RSA *RSA_parse_private_key(CBS *cbs);
597 
598 // RSA_private_key_from_bytes parses |in| as a DER-encoded RSAPrivateKey
599 // structure (RFC 8017). It returns a newly-allocated |RSA| or NULL on error.
600 OPENSSL_EXPORT RSA *RSA_private_key_from_bytes(const uint8_t *in,
601                                                size_t in_len);
602 
603 // RSA_marshal_private_key marshals |rsa| as a DER-encoded RSAPrivateKey
604 // structure (RFC 8017) and appends the result to |cbb|. It returns one on
605 // success and zero on failure.
606 OPENSSL_EXPORT int RSA_marshal_private_key(CBB *cbb, const RSA *rsa);
607 
608 // RSA_private_key_to_bytes marshals |rsa| as a DER-encoded RSAPrivateKey
609 // structure (RFC 8017) and, on success, sets |*out_bytes| to a newly allocated
610 // buffer containing the result and returns one. Otherwise, it returns zero. The
611 // result should be freed with |OPENSSL_free|.
612 OPENSSL_EXPORT int RSA_private_key_to_bytes(uint8_t **out_bytes,
613                                             size_t *out_len, const RSA *rsa);
614 
615 
616 // Obscure RSA variants.
617 //
618 // These functions allow creating RSA keys with obscure combinations of
619 // parameters.
620 
621 // RSA_new_private_key_no_crt behaves like |RSA_new_private_key| but constructs
622 // an RSA key without CRT coefficients.
623 //
624 // Keys created by this function will be less performant and cannot be
625 // serialized.
626 OPENSSL_EXPORT RSA *RSA_new_private_key_no_crt(const BIGNUM *n, const BIGNUM *e,
627                                                const BIGNUM *d);
628 
629 // RSA_new_private_key_no_e behaves like |RSA_new_private_key| but constructs an
630 // RSA key without CRT parameters or public exponent.
631 //
632 // Keys created by this function will be less performant, cannot be serialized,
633 // and lack hardening measures that protect against side channels and fault
634 // attacks.
635 OPENSSL_EXPORT RSA *RSA_new_private_key_no_e(const BIGNUM *n, const BIGNUM *d);
636 
637 // RSA_new_public_key_large_e behaves like |RSA_new_public_key| but allows any
638 // |e| up to |n|.
639 //
640 // BoringSSL typically bounds public exponents as a denial-of-service
641 // mitigation. Keys created by this function may perform worse than those
642 // created by |RSA_new_public_key|.
643 OPENSSL_EXPORT RSA *RSA_new_public_key_large_e(const BIGNUM *n,
644                                                const BIGNUM *e);
645 
646 // RSA_new_private_key_large_e behaves like |RSA_new_private_key| but allows any
647 // |e| up to |n|.
648 //
649 // BoringSSL typically bounds public exponents as a denial-of-service
650 // mitigation. Keys created by this function may perform worse than those
651 // created by |RSA_new_private_key|.
652 OPENSSL_EXPORT RSA *RSA_new_private_key_large_e(
653     const BIGNUM *n, const BIGNUM *e, const BIGNUM *d, const BIGNUM *p,
654     const BIGNUM *q, const BIGNUM *dmp1, const BIGNUM *dmq1,
655     const BIGNUM *iqmp);
656 
657 
658 // ex_data functions.
659 //
660 // See |ex_data.h| for details.
661 
662 OPENSSL_EXPORT int RSA_get_ex_new_index(long argl, void *argp,
663                                         CRYPTO_EX_unused *unused,
664                                         CRYPTO_EX_dup *dup_unused,
665                                         CRYPTO_EX_free *free_func);
666 OPENSSL_EXPORT int RSA_set_ex_data(RSA *rsa, int idx, void *arg);
667 OPENSSL_EXPORT void *RSA_get_ex_data(const RSA *rsa, int idx);
668 
669 
670 // Flags.
671 
672 // RSA_FLAG_OPAQUE specifies that this RSA_METHOD does not expose its key
673 // material. This may be set if, for instance, it is wrapping some other crypto
674 // API, like a platform key store.
675 #define RSA_FLAG_OPAQUE 1
676 
677 // RSA_FLAG_NO_BLINDING disables blinding of private operations, which is a
678 // dangerous thing to do. This flag is set internally as part of self-tests but
679 // is otherwise impossible to set externally.
680 #define RSA_FLAG_NO_BLINDING 8
681 
682 // RSA_FLAG_EXT_PKEY is deprecated and ignored.
683 #define RSA_FLAG_EXT_PKEY 0x20
684 
685 // RSA_FLAG_NO_PUBLIC_EXPONENT indicates that private keys without a public
686 // exponent are allowed. This is an internal constant. Use
687 // |RSA_new_private_key_no_e| to construct such keys.
688 #define RSA_FLAG_NO_PUBLIC_EXPONENT 0x40
689 
690 // RSA_FLAG_LARGE_PUBLIC_EXPONENT indicates that keys with a large public
691 // exponent are allowed. This is an internal constant. Use
692 // |RSA_new_public_key_large_e| and |RSA_new_private_key_large_e| to construct
693 // such keys.
694 #define RSA_FLAG_LARGE_PUBLIC_EXPONENT 0x80
695 
696 
697 // RSA public exponent values.
698 
699 #define RSA_3 0x3
700 #define RSA_F4 0x10001
701 
702 
703 // Deprecated functions.
704 
705 #define RSA_METHOD_FLAG_NO_CHECK RSA_FLAG_OPAQUE
706 
707 // RSA_flags returns the flags for |rsa|. These are a bitwise OR of |RSA_FLAG_*|
708 // constants.
709 OPENSSL_EXPORT int RSA_flags(const RSA *rsa);
710 
711 // RSA_test_flags returns the subset of flags in |flags| which are set in |rsa|.
712 OPENSSL_EXPORT int RSA_test_flags(const RSA *rsa, int flags);
713 
714 // RSA_blinding_on returns one.
715 OPENSSL_EXPORT int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
716 
717 // RSA_blinding_off does nothing.
718 OPENSSL_EXPORT void RSA_blinding_off(RSA *rsa);
719 
720 // RSA_generate_key behaves like |RSA_generate_key_ex|, which is what you
721 // should use instead. It returns NULL on error, or a newly-allocated |RSA| on
722 // success. This function is provided for compatibility only. The |callback|
723 // and |cb_arg| parameters must be NULL.
724 OPENSSL_EXPORT RSA *RSA_generate_key(int bits, uint64_t e, void *callback,
725                                      void *cb_arg);
726 
727 // d2i_RSAPublicKey parses a DER-encoded RSAPublicKey structure (RFC 8017) from
728 // |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
729 //
730 // Use |RSA_parse_public_key| instead.
731 OPENSSL_EXPORT RSA *d2i_RSAPublicKey(RSA **out, const uint8_t **inp, long len);
732 
733 // i2d_RSAPublicKey marshals |in| to a DER-encoded RSAPublicKey structure (RFC
734 // 8017), as described in |i2d_SAMPLE|.
735 //
736 // Use |RSA_marshal_public_key| instead.
737 OPENSSL_EXPORT int i2d_RSAPublicKey(const RSA *in, uint8_t **outp);
738 
739 // d2i_RSAPrivateKey parses a DER-encoded RSAPrivateKey structure (RFC 8017)
740 // from |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
741 //
742 // Use |RSA_parse_private_key| instead.
743 OPENSSL_EXPORT RSA *d2i_RSAPrivateKey(RSA **out, const uint8_t **inp, long len);
744 
745 // i2d_RSAPrivateKey marshals |in| to a DER-encoded RSAPrivateKey structure (RFC
746 // 8017), as described in |i2d_SAMPLE|.
747 //
748 // Use |RSA_marshal_private_key| instead.
749 OPENSSL_EXPORT int i2d_RSAPrivateKey(const RSA *in, uint8_t **outp);
750 
751 // RSA_padding_add_PKCS1_PSS acts like |RSA_padding_add_PKCS1_PSS_mgf1| but the
752 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
753 //
754 // This function implements only the low-level padding logic. Use
755 // |RSA_sign_pss_mgf1| instead.
756 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS(const RSA *rsa, uint8_t *EM,
757                                              const uint8_t *mHash,
758                                              const EVP_MD *Hash, int sLen);
759 
760 // RSA_verify_PKCS1_PSS acts like |RSA_verify_PKCS1_PSS_mgf1| but the
761 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
762 //
763 // This function implements only the low-level padding logic. Use
764 // |RSA_verify_pss_mgf1| instead.
765 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS(const RSA *rsa, const uint8_t *mHash,
766                                         const EVP_MD *Hash, const uint8_t *EM,
767                                         int sLen);
768 
769 // RSA_padding_add_PKCS1_OAEP acts like |RSA_padding_add_PKCS1_OAEP_mgf1| but
770 // the |md| and |mgf1md| parameters of the latter are implicitly set to NULL,
771 // which means SHA-1.
772 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP(uint8_t *to, size_t to_len,
773                                               const uint8_t *from,
774                                               size_t from_len,
775                                               const uint8_t *param,
776                                               size_t param_len);
777 
778 // RSA_print prints a textual representation of |rsa| to |bio|. It returns one
779 // on success or zero otherwise.
780 OPENSSL_EXPORT int RSA_print(BIO *bio, const RSA *rsa, int indent);
781 
782 // RSA_get0_pss_params returns NULL. In OpenSSL, this function retries RSA-PSS
783 // parameters associated with |RSA| objects, but BoringSSL does not support
784 // the id-RSASSA-PSS key encoding.
785 OPENSSL_EXPORT const RSA_PSS_PARAMS *RSA_get0_pss_params(const RSA *rsa);
786 
787 // RSA_new_method_no_e returns a newly-allocated |RSA| object backed by
788 // |engine|, with a public modulus of |n| and no known public exponent.
789 //
790 // Do not use this function. It exists only to support Conscrypt, whose use
791 // should be replaced with a more sound mechanism. See
792 // https://crbug.com/boringssl/602.
793 OPENSSL_EXPORT RSA *RSA_new_method_no_e(const ENGINE *engine, const BIGNUM *n);
794 
795 
796 struct rsa_meth_st {
797   struct openssl_method_common_st common;
798 
799   void *app_data;
800 
801   int (*init)(RSA *rsa);
802   int (*finish)(RSA *rsa);
803 
804   // size returns the size of the RSA modulus in bytes.
805   size_t (*size)(const RSA *rsa);
806 
807   int (*sign)(int type, const uint8_t *m, unsigned int m_length,
808               uint8_t *sigret, unsigned int *siglen, const RSA *rsa);
809 
810   // These functions mirror the |RSA_*| functions of the same name.
811   int (*sign_raw)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
812                   const uint8_t *in, size_t in_len, int padding);
813   int (*decrypt)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
814                  const uint8_t *in, size_t in_len, int padding);
815 
816   // private_transform takes a big-endian integer from |in|, calculates the
817   // d'th power of it, modulo the RSA modulus and writes the result as a
818   // big-endian integer to |out|. Both |in| and |out| are |len| bytes long and
819   // |len| is always equal to |RSA_size(rsa)|. If the result of the transform
820   // can be represented in fewer than |len| bytes, then |out| must be zero
821   // padded on the left.
822   //
823   // It returns one on success and zero otherwise.
824   //
825   // RSA decrypt and sign operations will call this, thus an ENGINE might wish
826   // to override it in order to avoid having to implement the padding
827   // functionality demanded by those, higher level, operations.
828   int (*private_transform)(RSA *rsa, uint8_t *out, const uint8_t *in,
829                            size_t len);
830 
831   int flags;
832 };
833 
834 
835 #if defined(__cplusplus)
836 }  // extern C
837 
838 extern "C++" {
839 
840 BSSL_NAMESPACE_BEGIN
841 
842 BORINGSSL_MAKE_DELETER(RSA, RSA_free)
843 BORINGSSL_MAKE_UP_REF(RSA, RSA_up_ref)
844 
845 BSSL_NAMESPACE_END
846 
847 }  // extern C++
848 
849 #endif
850 
851 #define RSA_R_BAD_ENCODING 100
852 #define RSA_R_BAD_E_VALUE 101
853 #define RSA_R_BAD_FIXED_HEADER_DECRYPT 102
854 #define RSA_R_BAD_PAD_BYTE_COUNT 103
855 #define RSA_R_BAD_RSA_PARAMETERS 104
856 #define RSA_R_BAD_SIGNATURE 105
857 #define RSA_R_BAD_VERSION 106
858 #define RSA_R_BLOCK_TYPE_IS_NOT_01 107
859 #define RSA_R_BN_NOT_INITIALIZED 108
860 #define RSA_R_CANNOT_RECOVER_MULTI_PRIME_KEY 109
861 #define RSA_R_CRT_PARAMS_ALREADY_GIVEN 110
862 #define RSA_R_CRT_VALUES_INCORRECT 111
863 #define RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN 112
864 #define RSA_R_DATA_TOO_LARGE 113
865 #define RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE 114
866 #define RSA_R_DATA_TOO_LARGE_FOR_MODULUS 115
867 #define RSA_R_DATA_TOO_SMALL 116
868 #define RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE 117
869 #define RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY 118
870 #define RSA_R_D_E_NOT_CONGRUENT_TO_1 119
871 #define RSA_R_EMPTY_PUBLIC_KEY 120
872 #define RSA_R_ENCODE_ERROR 121
873 #define RSA_R_FIRST_OCTET_INVALID 122
874 #define RSA_R_INCONSISTENT_SET_OF_CRT_VALUES 123
875 #define RSA_R_INTERNAL_ERROR 124
876 #define RSA_R_INVALID_MESSAGE_LENGTH 125
877 #define RSA_R_KEY_SIZE_TOO_SMALL 126
878 #define RSA_R_LAST_OCTET_INVALID 127
879 #define RSA_R_MODULUS_TOO_LARGE 128
880 #define RSA_R_MUST_HAVE_AT_LEAST_TWO_PRIMES 129
881 #define RSA_R_NO_PUBLIC_EXPONENT 130
882 #define RSA_R_NULL_BEFORE_BLOCK_MISSING 131
883 #define RSA_R_N_NOT_EQUAL_P_Q 132
884 #define RSA_R_OAEP_DECODING_ERROR 133
885 #define RSA_R_ONLY_ONE_OF_P_Q_GIVEN 134
886 #define RSA_R_OUTPUT_BUFFER_TOO_SMALL 135
887 #define RSA_R_PADDING_CHECK_FAILED 136
888 #define RSA_R_PKCS_DECODING_ERROR 137
889 #define RSA_R_SLEN_CHECK_FAILED 138
890 #define RSA_R_SLEN_RECOVERY_FAILED 139
891 #define RSA_R_TOO_LONG 140
892 #define RSA_R_TOO_MANY_ITERATIONS 141
893 #define RSA_R_UNKNOWN_ALGORITHM_TYPE 142
894 #define RSA_R_UNKNOWN_PADDING_TYPE 143
895 #define RSA_R_VALUE_MISSING 144
896 #define RSA_R_WRONG_SIGNATURE_LENGTH 145
897 #define RSA_R_PUBLIC_KEY_VALIDATION_FAILED 146
898 #define RSA_R_D_OUT_OF_RANGE 147
899 #define RSA_R_BLOCK_TYPE_IS_NOT_02 148
900 
901 #endif  // OPENSSL_HEADER_RSA_H
902