1 // Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #ifndef OPENSSL_HEADER_RSA_H
16 #define OPENSSL_HEADER_RSA_H
17 
18 #include <openssl/base.h>   // IWYU pragma: export
19 
20 #include <openssl/engine.h>
21 #include <openssl/ex_data.h>
22 
23 #if defined(__cplusplus)
24 extern "C" {
25 #endif
26 
27 
28 // rsa.h contains functions for handling encryption and signature using RSA.
29 
30 
31 // Allocation and destruction.
32 //
33 // An |RSA| object represents a public or private RSA key. A given object may be
34 // used concurrently on multiple threads by non-mutating functions, provided no
35 // other thread is concurrently calling a mutating function. Unless otherwise
36 // documented, functions which take a |const| pointer are non-mutating and
37 // functions which take a non-|const| pointer are mutating.
38 
39 // RSA_new_public_key returns a new |RSA| object containing a public key with
40 // the specified parameters, or NULL on error or invalid input.
41 OPENSSL_EXPORT RSA *RSA_new_public_key(const BIGNUM *n, const BIGNUM *e);
42 
43 // RSA_new_private_key returns a new |RSA| object containing a private key with
44 // the specified parameters, or NULL on error or invalid input. All parameters
45 // are mandatory and may not be NULL.
46 //
47 // This function creates standard RSA private keys with CRT parameters.
48 OPENSSL_EXPORT RSA *RSA_new_private_key(const BIGNUM *n, const BIGNUM *e,
49                                         const BIGNUM *d, const BIGNUM *p,
50                                         const BIGNUM *q, const BIGNUM *dmp1,
51                                         const BIGNUM *dmq1, const BIGNUM *iqmp);
52 
53 // RSA_new returns a new, empty |RSA| object or NULL on error. Prefer using
54 // |RSA_new_public_key| or |RSA_new_private_key| to import an RSA key.
55 OPENSSL_EXPORT RSA *RSA_new(void);
56 
57 // RSA_new_method acts the same as |RSA_new| but takes an explicit |ENGINE|.
58 OPENSSL_EXPORT RSA *RSA_new_method(const ENGINE *engine);
59 
60 // RSA_free decrements the reference count of |rsa| and frees it if the
61 // reference count drops to zero.
62 OPENSSL_EXPORT void RSA_free(RSA *rsa);
63 
64 // RSA_up_ref increments the reference count of |rsa| and returns one. It does
65 // not mutate |rsa| for thread-safety purposes and may be used concurrently.
66 OPENSSL_EXPORT int RSA_up_ref(RSA *rsa);
67 
68 
69 // Properties.
70 
71 // OPENSSL_RSA_MAX_MODULUS_BITS is the maximum supported RSA modulus, in bits.
72 #define OPENSSL_RSA_MAX_MODULUS_BITS 8192
73 
74 // RSA_bits returns the size of |rsa|, in bits.
75 OPENSSL_EXPORT unsigned RSA_bits(const RSA *rsa);
76 
77 // RSA_get0_n returns |rsa|'s public modulus.
78 OPENSSL_EXPORT const BIGNUM *RSA_get0_n(const RSA *rsa);
79 
80 // RSA_get0_e returns |rsa|'s public exponent.
81 OPENSSL_EXPORT const BIGNUM *RSA_get0_e(const RSA *rsa);
82 
83 // RSA_get0_d returns |rsa|'s private exponent. If |rsa| is a public key, this
84 // value will be NULL.
85 OPENSSL_EXPORT const BIGNUM *RSA_get0_d(const RSA *rsa);
86 
87 // RSA_get0_p returns |rsa|'s first private prime factor. If |rsa| is a public
88 // key or lacks its prime factors, this value will be NULL.
89 OPENSSL_EXPORT const BIGNUM *RSA_get0_p(const RSA *rsa);
90 
91 // RSA_get0_q returns |rsa|'s second private prime factor. If |rsa| is a public
92 // key or lacks its prime factors, this value will be NULL.
93 OPENSSL_EXPORT const BIGNUM *RSA_get0_q(const RSA *rsa);
94 
95 // RSA_get0_dmp1 returns d (mod p-1) for |rsa|. If |rsa| is a public key or
96 // lacks CRT parameters, this value will be NULL.
97 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmp1(const RSA *rsa);
98 
99 // RSA_get0_dmq1 returns d (mod q-1) for |rsa|. If |rsa| is a public key or
100 // lacks CRT parameters, this value will be NULL.
101 OPENSSL_EXPORT const BIGNUM *RSA_get0_dmq1(const RSA *rsa);
102 
103 // RSA_get0_iqmp returns q^-1 (mod p). If |rsa| is a public key or lacks CRT
104 // parameters, this value will be NULL.
105 OPENSSL_EXPORT const BIGNUM *RSA_get0_iqmp(const RSA *rsa);
106 
107 // RSA_get0_key sets |*out_n|, |*out_e|, and |*out_d|, if non-NULL, to |rsa|'s
108 // modulus, public exponent, and private exponent, respectively. If |rsa| is a
109 // public key, the private exponent will be set to NULL.
110 OPENSSL_EXPORT void RSA_get0_key(const RSA *rsa, const BIGNUM **out_n,
111                                  const BIGNUM **out_e, const BIGNUM **out_d);
112 
113 // RSA_get0_factors sets |*out_p| and |*out_q|, if non-NULL, to |rsa|'s prime
114 // factors. If |rsa| is a public key, they will be set to NULL.
115 OPENSSL_EXPORT void RSA_get0_factors(const RSA *rsa, const BIGNUM **out_p,
116                                      const BIGNUM **out_q);
117 
118 // RSA_get0_crt_params sets |*out_dmp1|, |*out_dmq1|, and |*out_iqmp|, if
119 // non-NULL, to |rsa|'s CRT parameters. These are d (mod p-1), d (mod q-1) and
120 // q^-1 (mod p), respectively. If |rsa| is a public key, each parameter will be
121 // set to NULL.
122 OPENSSL_EXPORT void RSA_get0_crt_params(const RSA *rsa, const BIGNUM **out_dmp1,
123                                         const BIGNUM **out_dmq1,
124                                         const BIGNUM **out_iqmp);
125 
126 
127 // Setting individual properties.
128 //
129 // These functions allow setting individual properties of an |RSA| object. This
130 // is typically used with |RSA_new| to construct an RSA key field by field.
131 // Prefer instead to use |RSA_new_public_key| and |RSA_new_private_key|. These
132 // functions defer some initialization to the first use of an |RSA| object. This
133 // means invalid inputs may be caught late.
134 //
135 // TODO(crbug.com/boringssl/316): This deferred initialization also causes
136 // performance problems in multi-threaded applications. The preferred APIs
137 // currently have the same issues, but they will initialize eagerly in the
138 // future.
139 
140 // RSA_set0_key sets |rsa|'s modulus, public exponent, and private exponent to
141 // |n|, |e|, and |d| respectively, if non-NULL. On success, it takes ownership
142 // of each argument and returns one. Otherwise, it returns zero.
143 //
144 // |d| may be NULL, but |n| and |e| must either be non-NULL or already
145 // configured on |rsa|.
146 //
147 // It is an error to call this function after |rsa| has been used for a
148 // cryptographic operation. Construct a new |RSA| object instead.
149 OPENSSL_EXPORT int RSA_set0_key(RSA *rsa, BIGNUM *n, BIGNUM *e, BIGNUM *d);
150 
151 // RSA_set0_factors sets |rsa|'s prime factors to |p| and |q|, if non-NULL, and
152 // takes ownership of them. On success, it takes ownership of each argument and
153 // returns one. Otherwise, it returns zero.
154 //
155 // Each argument must either be non-NULL or already configured on |rsa|.
156 //
157 // It is an error to call this function after |rsa| has been used for a
158 // cryptographic operation. Construct a new |RSA| object instead.
159 OPENSSL_EXPORT int RSA_set0_factors(RSA *rsa, BIGNUM *p, BIGNUM *q);
160 
161 // RSA_set0_crt_params sets |rsa|'s CRT parameters to |dmp1|, |dmq1|, and
162 // |iqmp|, if non-NULL, and takes ownership of them. On success, it takes
163 // ownership of its parameters and returns one. Otherwise, it returns zero.
164 //
165 // Each argument must either be non-NULL or already configured on |rsa|.
166 //
167 // It is an error to call this function after |rsa| has been used for a
168 // cryptographic operation. Construct a new |RSA| object instead.
169 OPENSSL_EXPORT int RSA_set0_crt_params(RSA *rsa, BIGNUM *dmp1, BIGNUM *dmq1,
170                                        BIGNUM *iqmp);
171 
172 
173 // Key generation.
174 
175 // RSA_generate_key_ex generates a new RSA key where the modulus has size
176 // |bits| and the public exponent is |e|. If unsure, |RSA_F4| is a good value
177 // for |e|. If |cb| is not NULL then it is called during the key generation
178 // process. In addition to the calls documented for |BN_generate_prime_ex|, it
179 // is called with event=2 when the n'th prime is rejected as unsuitable and
180 // with event=3 when a suitable value for |p| is found.
181 //
182 // It returns one on success or zero on error.
183 OPENSSL_EXPORT int RSA_generate_key_ex(RSA *rsa, int bits, const BIGNUM *e,
184                                        BN_GENCB *cb);
185 
186 // RSA_generate_key_fips behaves like |RSA_generate_key_ex| but performs
187 // additional checks for FIPS compliance. The public exponent is always 65537
188 // and |bits| must be either 2048 or 3072.
189 OPENSSL_EXPORT int RSA_generate_key_fips(RSA *rsa, int bits, BN_GENCB *cb);
190 
191 
192 // Encryption / Decryption
193 //
194 // These functions are considered non-mutating for thread-safety purposes and
195 // may be used concurrently.
196 
197 // RSA_PKCS1_PADDING denotes PKCS#1 v1.5 padding. When used with encryption,
198 // this is RSAES-PKCS1-v1_5. When used with signing, this is RSASSA-PKCS1-v1_5.
199 //
200 // WARNING: The RSAES-PKCS1-v1_5 encryption scheme is vulnerable to a
201 // chosen-ciphertext attack. Decrypting attacker-supplied ciphertext with
202 // RSAES-PKCS1-v1_5 may give the attacker control over your private key. This
203 // does not impact the RSASSA-PKCS1-v1_5 signature scheme. See "Chosen
204 // Ciphertext Attacks Against Protocols Based on the RSA Encryption Standard
205 // PKCS #1", Daniel Bleichenbacher, Advances in Cryptology (Crypto '98).
206 #define RSA_PKCS1_PADDING 1
207 
208 // RSA_NO_PADDING denotes a raw RSA operation.
209 #define RSA_NO_PADDING 3
210 
211 // RSA_PKCS1_OAEP_PADDING denotes the RSAES-OAEP encryption scheme.
212 #define RSA_PKCS1_OAEP_PADDING 4
213 
214 // RSA_PKCS1_PSS_PADDING denotes the RSASSA-PSS signature scheme. This value may
215 // not be passed into |RSA_sign_raw|, only |EVP_PKEY_CTX_set_rsa_padding|. See
216 // also |RSA_sign_pss_mgf1| and |RSA_verify_pss_mgf1|.
217 #define RSA_PKCS1_PSS_PADDING 6
218 
219 // RSA_encrypt encrypts |in_len| bytes from |in| to the public key from |rsa|
220 // and writes, at most, |max_out| bytes of encrypted data to |out|. The
221 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
222 //
223 // It returns 1 on success or zero on error.
224 //
225 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
226 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols. When |padding| is
227 // |RSA_PKCS1_OAEP_PADDING|, this function has no way to set the OAEP or MGF-1
228 // digest, so it is always SHA-1. For other OAEP parameters, wrap |rsa| in an
229 // |EVP_PKEY| and use |EVP_PKEY_encrypt| with |EVP_PKEY_CTX_set_rsa_padding| and
230 // related functions.
231 OPENSSL_EXPORT int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out,
232                                size_t max_out, const uint8_t *in, size_t in_len,
233                                int padding);
234 
235 // RSA_decrypt decrypts |in_len| bytes from |in| with the private key from
236 // |rsa| and writes, at most, |max_out| bytes of plaintext to |out|. The
237 // |max_out| argument must be, at least, |RSA_size| in order to ensure success.
238 //
239 // It returns 1 on success or zero on error.
240 //
241 // The |padding| argument must be one of the |RSA_*_PADDING| values. If in
242 // doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols. When |padding| is
243 // |RSA_PKCS1_OAEP_PADDING|, this function has no way to set the OAEP or MGF-1
244 // digest, so it is always SHA-1. For other OAEP parameters, wrap |rsa| in an
245 // |EVP_PKEY| and use |EVP_PKEY_decrypt| with |EVP_PKEY_CTX_set_rsa_padding| and
246 // related functions.
247 //
248 // WARNING: Passing |RSA_PKCS1_PADDING| into this function is deprecated and
249 // insecure. RSAES-PKCS1-v1_5 is vulnerable to a chosen-ciphertext attack.
250 // Decrypting attacker-supplied ciphertext with RSAES-PKCS1-v1_5 may give the
251 // attacker control over your private key. See "Chosen Ciphertext Attacks
252 // Against Protocols Based on the RSA Encryption Standard PKCS #1", Daniel
253 // Bleichenbacher, Advances in Cryptology (Crypto '98).
254 //
255 // In some limited cases, such as TLS RSA key exchange, it is possible to
256 // mitigate this flaw with custom, protocol-specific padding logic. This
257 // should be implemented with |RSA_NO_PADDING|, not |RSA_PKCS1_PADDING|.
258 OPENSSL_EXPORT int RSA_decrypt(RSA *rsa, size_t *out_len, uint8_t *out,
259                                size_t max_out, const uint8_t *in, size_t in_len,
260                                int padding);
261 
262 // RSA_public_encrypt encrypts |flen| bytes from |from| to the public key in
263 // |rsa| and writes the encrypted data to |to|. The |to| buffer must have at
264 // least |RSA_size| bytes of space. It returns the number of bytes written, or
265 // -1 on error. The |padding| argument must be one of the |RSA_*_PADDING|
266 // values. If in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols.
267 //
268 // When |padding| is |RSA_PKCS1_OAEP_PADDING|, this function has no way to set
269 // the OAEP or MGF-1 digest, so it is always SHA-1. For other OAEP parameters,
270 // wrap |rsa| in an |EVP_PKEY| and use |EVP_PKEY_encrypt| with
271 // |EVP_PKEY_CTX_set_rsa_padding| and related functions.
272 //
273 // WARNING: this function is dangerous because it breaks the usual return value
274 // convention. Use |RSA_encrypt| instead.
275 OPENSSL_EXPORT int RSA_public_encrypt(size_t flen, const uint8_t *from,
276                                       uint8_t *to, RSA *rsa, int padding);
277 
278 // RSA_private_decrypt decrypts |flen| bytes from |from| with the public key in
279 // |rsa| and writes the plaintext to |to|. The |to| buffer must have at least
280 // |RSA_size| bytes of space. It returns the number of bytes written, or -1 on
281 // error. The |padding| argument must be one of the |RSA_*_PADDING| values. If
282 // in doubt, use |RSA_PKCS1_OAEP_PADDING| for new protocols. Passing
283 // |RSA_PKCS1_PADDING| into this function is deprecated and insecure. See
284 // |RSA_decrypt|.
285 //
286 // When |padding| is |RSA_PKCS1_OAEP_PADDING|, this function has no way to set
287 // the OAEP or MGF-1 digest, so it is always SHA-1. For other OAEP parameters,
288 // wrap |rsa| in an |EVP_PKEY| and use |EVP_PKEY_decrypt| with
289 // |EVP_PKEY_CTX_set_rsa_padding| and related functions.
290 //
291 // WARNING: this function is dangerous because it breaks the usual return value
292 // convention. Use |RSA_decrypt| instead.
293 OPENSSL_EXPORT int RSA_private_decrypt(size_t flen, const uint8_t *from,
294                                        uint8_t *to, RSA *rsa, int padding);
295 
296 
297 // Signing / Verification
298 //
299 // These functions are considered non-mutating for thread-safety purposes and
300 // may be used concurrently.
301 
302 // RSA_sign signs |digest_len| bytes of digest from |digest| with |rsa| using
303 // RSASSA-PKCS1-v1_5. It writes, at most, |RSA_size(rsa)| bytes to |out|. On
304 // successful return, the actual number of bytes written is written to
305 // |*out_len|.
306 //
307 // The |hash_nid| argument identifies the hash function used to calculate
308 // |digest| and is embedded in the resulting signature. For example, it might be
309 // |NID_sha256|.
310 //
311 // It returns 1 on success and zero on error.
312 //
313 // WARNING: |digest| must be the result of hashing the data to be signed with
314 // |hash_nid|. Passing unhashed inputs will not result in a secure signature
315 // scheme.
316 OPENSSL_EXPORT int RSA_sign(int hash_nid, const uint8_t *digest,
317                             size_t digest_len, uint8_t *out, unsigned *out_len,
318                             RSA *rsa);
319 
320 // RSA_PSS_SALTLEN_DIGEST indicates a PSS salt length that matches the digest
321 // length. This is recommended.
322 #define RSA_PSS_SALTLEN_DIGEST (-1)
323 // RSA_PSS_SALTLEN_AUTO indicates a maximum possible PSS salt length when
324 // signing, and automatically detecting the salt length when verifying. This is
325 // not recommended. Neither the signing nor verifying behaviors are compliant
326 // with FIPS 186-5.
327 #define RSA_PSS_SALTLEN_AUTO (-2)
328 
329 // RSA_sign_pss_mgf1 signs |digest_len| bytes from |digest| with the public key
330 // from |rsa| using RSASSA-PSS with MGF1 as the mask generation function. It
331 // writes, at most, |max_out| bytes of signature data to |out|. The |max_out|
332 // argument must be, at least, |RSA_size| in order to ensure success. It returns
333 // 1 on success or zero on error.
334 //
335 // The |md| and |mgf1_md| arguments identify the hash used to calculate |digest|
336 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
337 // used.
338 //
339 // |salt_len| specifies the expected salt length in bytes. If |salt_len| is
340 // |RSA_PSS_SALTLEN_DIGEST|, then the salt length is the same as the hash
341 // length. If |RSA_PSS_SALTLEN_AUTO|, then the salt length is maximal given the
342 // size of |rsa|. If unsure, use |RSA_PSS_SALTLEN_DIGEST|.
343 //
344 // WARNING: |digest| must be the result of hashing the data to be signed with
345 // |md|. Passing unhashed inputs will not result in a secure signature scheme.
346 OPENSSL_EXPORT int RSA_sign_pss_mgf1(RSA *rsa, size_t *out_len, uint8_t *out,
347                                      size_t max_out, const uint8_t *digest,
348                                      size_t digest_len, const EVP_MD *md,
349                                      const EVP_MD *mgf1_md, int salt_len);
350 
351 // RSA_sign_raw performs the private key portion of computing a signature with
352 // |rsa|. It writes, at most, |max_out| bytes of signature data to |out|. The
353 // |max_out| argument must be, at least, |RSA_size| in order to ensure the
354 // output fits. It returns 1 on success or zero on error.
355 //
356 // If |padding| is |RSA_PKCS1_PADDING|, this function wraps |in| with the
357 // padding portion of RSASSA-PKCS1-v1_5 and then performs the raw private key
358 // operation. The caller is responsible for hashing the input and wrapping it in
359 // a DigestInfo structure.
360 //
361 // If |padding| is |RSA_NO_PADDING|, this function only performs the raw private
362 // key operation, interpreting |in| as a integer modulo n. The caller is
363 // responsible for hashing the input and encoding it for the signature scheme
364 // being implemented.
365 //
366 // WARNING: This function is a building block for a signature scheme, not a
367 // complete one. |in| must be the result of hashing and encoding the data as
368 // needed for the scheme being implemented. Passing in arbitrary inputs will not
369 // result in a secure signature scheme.
370 OPENSSL_EXPORT int RSA_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out,
371                                 size_t max_out, const uint8_t *in,
372                                 size_t in_len, int padding);
373 
374 // RSA_verify verifies that |sig_len| bytes from |sig| are a valid,
375 // RSASSA-PKCS1-v1_5 signature of |digest_len| bytes at |digest| by |rsa|.
376 //
377 // The |hash_nid| argument identifies the hash function used to calculate
378 // |digest| and is embedded in the resulting signature in order to prevent hash
379 // confusion attacks. For example, it might be |NID_sha256|.
380 //
381 // It returns one if the signature is valid and zero otherwise.
382 //
383 // WARNING: this differs from the original, OpenSSL function which additionally
384 // returned -1 on error.
385 //
386 // WARNING: |digest| must be the result of hashing the data to be verified with
387 // |hash_nid|. Passing unhashed input will not result in a secure signature
388 // scheme.
389 OPENSSL_EXPORT int RSA_verify(int hash_nid, const uint8_t *digest,
390                               size_t digest_len, const uint8_t *sig,
391                               size_t sig_len, RSA *rsa);
392 
393 // RSA_verify_pss_mgf1 verifies that |sig_len| bytes from |sig| are a valid,
394 // RSASSA-PSS signature of |digest_len| bytes at |digest| by |rsa|. It returns
395 // one if the signature is valid and zero otherwise. MGF1 is used as the mask
396 // generation function.
397 //
398 // The |md| and |mgf1_md| arguments identify the hash used to calculate |digest|
399 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
400 // used. |salt_len| specifies the expected salt length in bytes.
401 //
402 // If |salt_len| is |RSA_PSS_SALTLEN_DIGEST|, then the salt length is the same
403 // as the hash length. If |RSA_PSS_SALTLEN_AUTO|, then the salt length is
404 // recovered and all values accepted. If unsure, use |RSA_PSS_SALTLEN_DIGEST|.
405 //
406 // WARNING: |digest| must be the result of hashing the data to be verified with
407 // |md|. Passing unhashed input will not result in a secure signature scheme.
408 OPENSSL_EXPORT int RSA_verify_pss_mgf1(RSA *rsa, const uint8_t *digest,
409                                        size_t digest_len, const EVP_MD *md,
410                                        const EVP_MD *mgf1_md, int salt_len,
411                                        const uint8_t *sig, size_t sig_len);
412 
413 // RSA_verify_raw performs the public key portion of verifying |in_len| bytes of
414 // signature from |in| using the public key from |rsa|. On success, it returns
415 // one and writes, at most, |max_out| bytes of output to |out|. The |max_out|
416 // argument must be, at least, |RSA_size| in order to ensure the output fits. On
417 // failure or invalid input, it returns zero.
418 //
419 // If |padding| is |RSA_PKCS1_PADDING|, this function checks the padding portion
420 // of RSASSA-PKCS1-v1_5 and outputs the remainder of the encoded digest. The
421 // caller is responsible for checking the output is a DigestInfo-wrapped digest
422 // of the message.
423 //
424 // If |padding| is |RSA_NO_PADDING|, this function only performs the raw public
425 // key operation. The caller is responsible for checking the output is a valid
426 // result for the signature scheme being implemented.
427 //
428 // WARNING: This function is a building block for a signature scheme, not a
429 // complete one. Checking for arbitrary strings in |out| will not result in a
430 // secure signature scheme.
431 OPENSSL_EXPORT int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out,
432                                   size_t max_out, const uint8_t *in,
433                                   size_t in_len, int padding);
434 
435 // RSA_private_encrypt performs the private key portion of computing a signature
436 // with |rsa|. It takes |flen| bytes from |from| as input and writes the result
437 // to |to|. The |to| buffer must have at least |RSA_size| bytes of space. It
438 // returns the number of bytes written, or -1 on error.
439 //
440 // For the interpretation of |padding| and the input, see |RSA_sign_raw|.
441 //
442 // WARNING: This function is a building block for a signature scheme, not a
443 // complete one. See |RSA_sign_raw| for details.
444 //
445 // WARNING: This function is dangerous because it breaks the usual return value
446 // convention. Use |RSA_sign_raw| instead.
447 OPENSSL_EXPORT int RSA_private_encrypt(size_t flen, const uint8_t *from,
448                                        uint8_t *to, RSA *rsa, int padding);
449 
450 // RSA_public_decrypt performs the public key portion of verifying |flen| bytes
451 // of signature from |from| using the public key from |rsa|. It writes the
452 // result to |to|, which must have at least |RSA_size| bytes of space. It
453 // returns the number of bytes written, or -1 on error.
454 //
455 // For the interpretation of |padding| and the result, see |RSA_verify_raw|.
456 //
457 // WARNING: This function is a building block for a signature scheme, not a
458 // complete one. See |RSA_verify_raw| for details.
459 //
460 // WARNING: This function is dangerous because it breaks the usual return value
461 // convention. Use |RSA_verify_raw| instead.
462 OPENSSL_EXPORT int RSA_public_decrypt(size_t flen, const uint8_t *from,
463                                       uint8_t *to, RSA *rsa, int padding);
464 
465 
466 // Utility functions.
467 
468 // RSA_size returns the number of bytes in the modulus, which is also the size
469 // of a signature or encrypted value using |rsa|.
470 OPENSSL_EXPORT unsigned RSA_size(const RSA *rsa);
471 
472 // RSA_is_opaque returns one if |rsa| is opaque and doesn't expose its key
473 // material. Otherwise it returns zero.
474 OPENSSL_EXPORT int RSA_is_opaque(const RSA *rsa);
475 
476 // RSAPublicKey_dup allocates a fresh |RSA| and copies the public key from
477 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
478 OPENSSL_EXPORT RSA *RSAPublicKey_dup(const RSA *rsa);
479 
480 // RSAPrivateKey_dup allocates a fresh |RSA| and copies the private key from
481 // |rsa| into it. It returns the fresh |RSA| object, or NULL on error.
482 OPENSSL_EXPORT RSA *RSAPrivateKey_dup(const RSA *rsa);
483 
484 // RSA_check_key performs basic validity tests on |rsa|. It returns one if
485 // they pass and zero otherwise. Opaque keys and public keys always pass. If it
486 // returns zero then a more detailed error is available on the error queue.
487 OPENSSL_EXPORT int RSA_check_key(const RSA *rsa);
488 
489 // RSA_check_fips performs public key validity tests on |key|. It returns one if
490 // they pass and zero otherwise. Opaque keys always fail. This function does not
491 // mutate |rsa| for thread-safety purposes and may be used concurrently.
492 OPENSSL_EXPORT int RSA_check_fips(RSA *key);
493 
494 // RSA_verify_PKCS1_PSS_mgf1 verifies that |EM| is a correct PSS padding of
495 // |mHash|, where |mHash| is a digest produced by |Hash|. |EM| must point to
496 // exactly |RSA_size(rsa)| bytes of data. The |mgf1Hash| argument specifies the
497 // hash function for generating the mask. If NULL, |Hash| is used. The |sLen|
498 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
499 // the salt length is the same as the hash length. If -2, then the salt length
500 // is recovered and all values accepted.
501 //
502 // If unsure, use -1.
503 //
504 // It returns one on success or zero on error.
505 //
506 // This function implements only the low-level padding logic. Use
507 // |RSA_verify_pss_mgf1| instead.
508 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS_mgf1(const RSA *rsa,
509                                              const uint8_t *mHash,
510                                              const EVP_MD *Hash,
511                                              const EVP_MD *mgf1Hash,
512                                              const uint8_t *EM, int sLen);
513 
514 // RSA_padding_add_PKCS1_PSS_mgf1 writes a PSS padding of |mHash| to |EM|,
515 // where |mHash| is a digest produced by |Hash|. |RSA_size(rsa)| bytes of
516 // output will be written to |EM|. The |mgf1Hash| argument specifies the hash
517 // function for generating the mask. If NULL, |Hash| is used. The |sLen|
518 // argument specifies the expected salt length in bytes. If |sLen| is -1 then
519 // the salt length is the same as the hash length. If -2, then the salt length
520 // is maximal given the space in |EM|.
521 //
522 // It returns one on success or zero on error.
523 //
524 // This function implements only the low-level padding logic. Use
525 // |RSA_sign_pss_mgf1| instead.
526 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS_mgf1(const RSA *rsa, uint8_t *EM,
527                                                   const uint8_t *mHash,
528                                                   const EVP_MD *Hash,
529                                                   const EVP_MD *mgf1Hash,
530                                                   int sLen);
531 
532 // RSA_padding_add_PKCS1_OAEP_mgf1 writes an OAEP padding of |from| to |to|
533 // with the given parameters and hash functions. If |md| is NULL then SHA-1 is
534 // used. If |mgf1md| is NULL then the value of |md| is used (which means SHA-1
535 // if that, in turn, is NULL).
536 //
537 // It returns one on success or zero on error.
538 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP_mgf1(
539     uint8_t *to, size_t to_len, const uint8_t *from, size_t from_len,
540     const uint8_t *param, size_t param_len, const EVP_MD *md,
541     const EVP_MD *mgf1md);
542 
543 // RSA_add_pkcs1_prefix builds a version of |digest| prefixed with the
544 // DigestInfo header for the given hash function and sets |out_msg| to point to
545 // it. On successful return, if |*is_alloced| is one, the caller must release
546 // |*out_msg| with |OPENSSL_free|.
547 OPENSSL_EXPORT int RSA_add_pkcs1_prefix(uint8_t **out_msg, size_t *out_msg_len,
548                                         int *is_alloced, int hash_nid,
549                                         const uint8_t *digest,
550                                         size_t digest_len);
551 
552 
553 // ASN.1 functions.
554 
555 // RSA_parse_public_key parses a DER-encoded RSAPublicKey structure (RFC 8017)
556 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
557 // error.
558 OPENSSL_EXPORT RSA *RSA_parse_public_key(CBS *cbs);
559 
560 // RSA_public_key_from_bytes parses |in| as a DER-encoded RSAPublicKey structure
561 // (RFC 8017). It returns a newly-allocated |RSA| or NULL on error.
562 OPENSSL_EXPORT RSA *RSA_public_key_from_bytes(const uint8_t *in, size_t in_len);
563 
564 // RSA_marshal_public_key marshals |rsa| as a DER-encoded RSAPublicKey structure
565 // (RFC 8017) and appends the result to |cbb|. It returns one on success and
566 // zero on failure.
567 OPENSSL_EXPORT int RSA_marshal_public_key(CBB *cbb, const RSA *rsa);
568 
569 // RSA_public_key_to_bytes marshals |rsa| as a DER-encoded RSAPublicKey
570 // structure (RFC 8017) and, on success, sets |*out_bytes| to a newly allocated
571 // buffer containing the result and returns one. Otherwise, it returns zero. The
572 // result should be freed with |OPENSSL_free|.
573 OPENSSL_EXPORT int RSA_public_key_to_bytes(uint8_t **out_bytes, size_t *out_len,
574                                            const RSA *rsa);
575 
576 // RSA_parse_private_key parses a DER-encoded RSAPrivateKey structure (RFC 8017)
577 // from |cbs| and advances |cbs|. It returns a newly-allocated |RSA| or NULL on
578 // error.
579 OPENSSL_EXPORT RSA *RSA_parse_private_key(CBS *cbs);
580 
581 // RSA_private_key_from_bytes parses |in| as a DER-encoded RSAPrivateKey
582 // structure (RFC 8017). It returns a newly-allocated |RSA| or NULL on error.
583 OPENSSL_EXPORT RSA *RSA_private_key_from_bytes(const uint8_t *in,
584                                                size_t in_len);
585 
586 // RSA_marshal_private_key marshals |rsa| as a DER-encoded RSAPrivateKey
587 // structure (RFC 8017) and appends the result to |cbb|. It returns one on
588 // success and zero on failure.
589 OPENSSL_EXPORT int RSA_marshal_private_key(CBB *cbb, const RSA *rsa);
590 
591 // RSA_private_key_to_bytes marshals |rsa| as a DER-encoded RSAPrivateKey
592 // structure (RFC 8017) and, on success, sets |*out_bytes| to a newly allocated
593 // buffer containing the result and returns one. Otherwise, it returns zero. The
594 // result should be freed with |OPENSSL_free|.
595 OPENSSL_EXPORT int RSA_private_key_to_bytes(uint8_t **out_bytes,
596                                             size_t *out_len, const RSA *rsa);
597 
598 
599 // Obscure RSA variants.
600 //
601 // These functions allow creating RSA keys with obscure combinations of
602 // parameters.
603 
604 // RSA_new_private_key_no_crt behaves like |RSA_new_private_key| but constructs
605 // an RSA key without CRT coefficients.
606 //
607 // Keys created by this function will be less performant and cannot be
608 // serialized.
609 OPENSSL_EXPORT RSA *RSA_new_private_key_no_crt(const BIGNUM *n, const BIGNUM *e,
610                                                const BIGNUM *d);
611 
612 // RSA_new_private_key_no_e behaves like |RSA_new_private_key| but constructs an
613 // RSA key without CRT parameters or public exponent.
614 //
615 // Keys created by this function will be less performant, cannot be serialized,
616 // and lack hardening measures that protect against side channels and fault
617 // attacks.
618 OPENSSL_EXPORT RSA *RSA_new_private_key_no_e(const BIGNUM *n, const BIGNUM *d);
619 
620 // RSA_new_public_key_large_e behaves like |RSA_new_public_key| but allows any
621 // |e| up to |n|.
622 //
623 // BoringSSL typically bounds public exponents as a denial-of-service
624 // mitigation. Keys created by this function may perform worse than those
625 // created by |RSA_new_public_key|.
626 OPENSSL_EXPORT RSA *RSA_new_public_key_large_e(const BIGNUM *n,
627                                                const BIGNUM *e);
628 
629 // RSA_new_private_key_large_e behaves like |RSA_new_private_key| but allows any
630 // |e| up to |n|.
631 //
632 // BoringSSL typically bounds public exponents as a denial-of-service
633 // mitigation. Keys created by this function may perform worse than those
634 // created by |RSA_new_private_key|.
635 OPENSSL_EXPORT RSA *RSA_new_private_key_large_e(
636     const BIGNUM *n, const BIGNUM *e, const BIGNUM *d, const BIGNUM *p,
637     const BIGNUM *q, const BIGNUM *dmp1, const BIGNUM *dmq1,
638     const BIGNUM *iqmp);
639 
640 
641 // ex_data functions.
642 //
643 // See |ex_data.h| for details.
644 
645 OPENSSL_EXPORT int RSA_get_ex_new_index(long argl, void *argp,
646                                         CRYPTO_EX_unused *unused,
647                                         CRYPTO_EX_dup *dup_unused,
648                                         CRYPTO_EX_free *free_func);
649 OPENSSL_EXPORT int RSA_set_ex_data(RSA *rsa, int idx, void *arg);
650 OPENSSL_EXPORT void *RSA_get_ex_data(const RSA *rsa, int idx);
651 
652 
653 // Flags.
654 
655 // RSA_FLAG_OPAQUE specifies that this RSA_METHOD does not expose its key
656 // material. This may be set if, for instance, it is wrapping some other crypto
657 // API, like a platform key store.
658 #define RSA_FLAG_OPAQUE 1
659 
660 // RSA_FLAG_NO_BLINDING disables blinding of private operations, which is a
661 // dangerous thing to do. This flag is set internally as part of self-tests but
662 // is otherwise impossible to set externally.
663 #define RSA_FLAG_NO_BLINDING 8
664 
665 // RSA_FLAG_EXT_PKEY is deprecated and ignored.
666 #define RSA_FLAG_EXT_PKEY 0x20
667 
668 // RSA_FLAG_NO_PUBLIC_EXPONENT indicates that private keys without a public
669 // exponent are allowed. This is an internal constant. Use
670 // |RSA_new_private_key_no_e| to construct such keys.
671 #define RSA_FLAG_NO_PUBLIC_EXPONENT 0x40
672 
673 // RSA_FLAG_LARGE_PUBLIC_EXPONENT indicates that keys with a large public
674 // exponent are allowed. This is an internal constant. Use
675 // |RSA_new_public_key_large_e| and |RSA_new_private_key_large_e| to construct
676 // such keys.
677 #define RSA_FLAG_LARGE_PUBLIC_EXPONENT 0x80
678 
679 
680 // RSA public exponent values.
681 
682 #define RSA_3 0x3
683 #define RSA_F4 0x10001
684 
685 
686 // Deprecated functions.
687 
688 #define RSA_METHOD_FLAG_NO_CHECK RSA_FLAG_OPAQUE
689 
690 // RSA_flags returns the flags for |rsa|. These are a bitwise OR of |RSA_FLAG_*|
691 // constants.
692 OPENSSL_EXPORT int RSA_flags(const RSA *rsa);
693 
694 // RSA_test_flags returns the subset of flags in |flags| which are set in |rsa|.
695 OPENSSL_EXPORT int RSA_test_flags(const RSA *rsa, int flags);
696 
697 // RSA_blinding_on returns one.
698 OPENSSL_EXPORT int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
699 
700 // RSA_blinding_off does nothing.
701 OPENSSL_EXPORT void RSA_blinding_off(RSA *rsa);
702 
703 // RSA_generate_key behaves like |RSA_generate_key_ex|, which is what you
704 // should use instead. It returns NULL on error, or a newly-allocated |RSA| on
705 // success. This function is provided for compatibility only. The |callback|
706 // and |cb_arg| parameters must be NULL.
707 OPENSSL_EXPORT RSA *RSA_generate_key(int bits, uint64_t e, void *callback,
708                                      void *cb_arg);
709 
710 // d2i_RSAPublicKey parses a DER-encoded RSAPublicKey structure (RFC 8017) from
711 // |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
712 //
713 // Use |RSA_parse_public_key| instead.
714 OPENSSL_EXPORT RSA *d2i_RSAPublicKey(RSA **out, const uint8_t **inp, long len);
715 
716 // i2d_RSAPublicKey marshals |in| to a DER-encoded RSAPublicKey structure (RFC
717 // 8017), as described in |i2d_SAMPLE|.
718 //
719 // Use |RSA_marshal_public_key| instead.
720 OPENSSL_EXPORT int i2d_RSAPublicKey(const RSA *in, uint8_t **outp);
721 
722 // d2i_RSAPrivateKey parses a DER-encoded RSAPrivateKey structure (RFC 8017)
723 // from |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
724 //
725 // Use |RSA_parse_private_key| instead.
726 OPENSSL_EXPORT RSA *d2i_RSAPrivateKey(RSA **out, const uint8_t **inp, long len);
727 
728 // i2d_RSAPrivateKey marshals |in| to a DER-encoded RSAPrivateKey structure (RFC
729 // 8017), as described in |i2d_SAMPLE|.
730 //
731 // Use |RSA_marshal_private_key| instead.
732 OPENSSL_EXPORT int i2d_RSAPrivateKey(const RSA *in, uint8_t **outp);
733 
734 // RSA_padding_add_PKCS1_PSS acts like |RSA_padding_add_PKCS1_PSS_mgf1| but the
735 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
736 //
737 // This function implements only the low-level padding logic. Use
738 // |RSA_sign_pss_mgf1| instead.
739 OPENSSL_EXPORT int RSA_padding_add_PKCS1_PSS(const RSA *rsa, uint8_t *EM,
740                                              const uint8_t *mHash,
741                                              const EVP_MD *Hash, int sLen);
742 
743 // RSA_verify_PKCS1_PSS acts like |RSA_verify_PKCS1_PSS_mgf1| but the
744 // |mgf1Hash| parameter of the latter is implicitly set to |Hash|.
745 //
746 // This function implements only the low-level padding logic. Use
747 // |RSA_verify_pss_mgf1| instead.
748 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS(const RSA *rsa, const uint8_t *mHash,
749                                         const EVP_MD *Hash, const uint8_t *EM,
750                                         int sLen);
751 
752 // RSA_padding_add_PKCS1_OAEP acts like |RSA_padding_add_PKCS1_OAEP_mgf1| but
753 // the |md| and |mgf1md| parameters of the latter are implicitly set to NULL,
754 // which means SHA-1.
755 OPENSSL_EXPORT int RSA_padding_add_PKCS1_OAEP(uint8_t *to, size_t to_len,
756                                               const uint8_t *from,
757                                               size_t from_len,
758                                               const uint8_t *param,
759                                               size_t param_len);
760 
761 // RSA_print prints a textual representation of |rsa| to |bio|. It returns one
762 // on success or zero otherwise.
763 OPENSSL_EXPORT int RSA_print(BIO *bio, const RSA *rsa, int indent);
764 
765 // RSA_get0_pss_params returns NULL. In OpenSSL, this function retries RSA-PSS
766 // parameters associated with |RSA| objects, but BoringSSL does not support
767 // the id-RSASSA-PSS key encoding.
768 OPENSSL_EXPORT const RSA_PSS_PARAMS *RSA_get0_pss_params(const RSA *rsa);
769 
770 // RSA_new_method_no_e returns a newly-allocated |RSA| object backed by
771 // |engine|, with a public modulus of |n| and no known public exponent.
772 //
773 // Do not use this function. It exists only to support Conscrypt, whose use
774 // should be replaced with a more sound mechanism. See
775 // https://crbug.com/boringssl/602.
776 OPENSSL_EXPORT RSA *RSA_new_method_no_e(const ENGINE *engine, const BIGNUM *n);
777 
778 
779 struct rsa_meth_st {
780   struct openssl_method_common_st common;
781 
782   void *app_data;
783 
784   int (*init)(RSA *rsa);
785   int (*finish)(RSA *rsa);
786 
787   int (*sign)(int type, const uint8_t *m, unsigned int m_length,
788               uint8_t *sigret, unsigned int *siglen, const RSA *rsa);
789 
790   // These functions mirror the |RSA_*| functions of the same name.
791   int (*sign_raw)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
792                   const uint8_t *in, size_t in_len, int padding);
793   int (*decrypt)(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
794                  const uint8_t *in, size_t in_len, int padding);
795 
796   // private_transform takes a big-endian integer from |in|, calculates the
797   // d'th power of it, modulo the RSA modulus and writes the result as a
798   // big-endian integer to |out|. Both |in| and |out| are |len| bytes long and
799   // |len| is always equal to |RSA_size(rsa)|. If the result of the transform
800   // can be represented in fewer than |len| bytes, then |out| must be zero
801   // padded on the left.
802   //
803   // It returns one on success and zero otherwise.
804   //
805   // RSA decrypt and sign operations will call this, thus an ENGINE might wish
806   // to override it in order to avoid having to implement the padding
807   // functionality demanded by those, higher level, operations.
808   int (*private_transform)(RSA *rsa, uint8_t *out, const uint8_t *in,
809                            size_t len);
810 
811   int flags;
812 };
813 
814 
815 #if defined(__cplusplus)
816 }  // extern C
817 
818 extern "C++" {
819 
820 BSSL_NAMESPACE_BEGIN
821 
822 BORINGSSL_MAKE_DELETER(RSA, RSA_free)
823 BORINGSSL_MAKE_UP_REF(RSA, RSA_up_ref)
824 
825 BSSL_NAMESPACE_END
826 
827 }  // extern C++
828 
829 #endif
830 
831 #define RSA_R_BAD_ENCODING 100
832 #define RSA_R_BAD_E_VALUE 101
833 #define RSA_R_BAD_FIXED_HEADER_DECRYPT 102
834 #define RSA_R_BAD_PAD_BYTE_COUNT 103
835 #define RSA_R_BAD_RSA_PARAMETERS 104
836 #define RSA_R_BAD_SIGNATURE 105
837 #define RSA_R_BAD_VERSION 106
838 #define RSA_R_BLOCK_TYPE_IS_NOT_01 107
839 #define RSA_R_BN_NOT_INITIALIZED 108
840 #define RSA_R_CANNOT_RECOVER_MULTI_PRIME_KEY 109
841 #define RSA_R_CRT_PARAMS_ALREADY_GIVEN 110
842 #define RSA_R_CRT_VALUES_INCORRECT 111
843 #define RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN 112
844 #define RSA_R_DATA_TOO_LARGE 113
845 #define RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE 114
846 #define RSA_R_DATA_TOO_LARGE_FOR_MODULUS 115
847 #define RSA_R_DATA_TOO_SMALL 116
848 #define RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE 117
849 #define RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY 118
850 #define RSA_R_D_E_NOT_CONGRUENT_TO_1 119
851 #define RSA_R_EMPTY_PUBLIC_KEY 120
852 #define RSA_R_ENCODE_ERROR 121
853 #define RSA_R_FIRST_OCTET_INVALID 122
854 #define RSA_R_INCONSISTENT_SET_OF_CRT_VALUES 123
855 #define RSA_R_INTERNAL_ERROR 124
856 #define RSA_R_INVALID_MESSAGE_LENGTH 125
857 #define RSA_R_KEY_SIZE_TOO_SMALL 126
858 #define RSA_R_LAST_OCTET_INVALID 127
859 #define RSA_R_MODULUS_TOO_LARGE 128
860 #define RSA_R_MUST_HAVE_AT_LEAST_TWO_PRIMES 129
861 #define RSA_R_NO_PUBLIC_EXPONENT 130
862 #define RSA_R_NULL_BEFORE_BLOCK_MISSING 131
863 #define RSA_R_N_NOT_EQUAL_P_Q 132
864 #define RSA_R_OAEP_DECODING_ERROR 133
865 #define RSA_R_ONLY_ONE_OF_P_Q_GIVEN 134
866 #define RSA_R_OUTPUT_BUFFER_TOO_SMALL 135
867 #define RSA_R_PADDING_CHECK_FAILED 136
868 #define RSA_R_PKCS_DECODING_ERROR 137
869 #define RSA_R_SLEN_CHECK_FAILED 138
870 #define RSA_R_SLEN_RECOVERY_FAILED 139
871 #define RSA_R_TOO_LONG 140
872 #define RSA_R_TOO_MANY_ITERATIONS 141
873 #define RSA_R_UNKNOWN_ALGORITHM_TYPE 142
874 #define RSA_R_UNKNOWN_PADDING_TYPE 143
875 #define RSA_R_VALUE_MISSING 144
876 #define RSA_R_WRONG_SIGNATURE_LENGTH 145
877 #define RSA_R_PUBLIC_KEY_VALIDATION_FAILED 146
878 #define RSA_R_D_OUT_OF_RANGE 147
879 #define RSA_R_BLOCK_TYPE_IS_NOT_02 148
880 
881 #endif  // OPENSSL_HEADER_RSA_H
882