2 * Copyright 2005-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 * RSA low level APIs are deprecated for public use, but still ok for
14 #include "internal/deprecated.h"
17 #include "internal/cryptlib.h"
18 #include <openssl/bn.h>
19 #include <openssl/rsa.h>
20 #include <openssl/evp.h>
21 #include <openssl/rand.h>
22 #include <openssl/sha.h>
23 #include "rsa_local.h"
25 static const unsigned char zeroes
[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
27 #if defined(_MSC_VER) && defined(_ARM_)
28 # pragma optimize("g", off)
31 int RSA_verify_PKCS1_PSS(RSA
*rsa
, const unsigned char *mHash
,
32 const EVP_MD
*Hash
, const unsigned char *EM
,
35 return RSA_verify_PKCS1_PSS_mgf1(rsa
, mHash
, Hash
, NULL
, EM
, sLen
);
38 int RSA_verify_PKCS1_PSS_mgf1(RSA
*rsa
, const unsigned char *mHash
,
39 const EVP_MD
*Hash
, const EVP_MD
*mgf1Hash
,
40 const unsigned char *EM
, int sLen
)
44 int hLen
, maskedDBLen
, MSBits
, emLen
;
45 const unsigned char *H
;
46 unsigned char *DB
= NULL
;
47 EVP_MD_CTX
*ctx
= EVP_MD_CTX_new();
48 unsigned char H_
[EVP_MAX_MD_SIZE
];
56 hLen
= EVP_MD_get_size(Hash
);
60 * Negative sLen has special meanings:
62 * -2 salt length is autorecovered from signature
63 * -3 salt length is maximized
64 * -4 salt length is autorecovered from signature
67 if (sLen
== RSA_PSS_SALTLEN_DIGEST
) {
69 } else if (sLen
< RSA_PSS_SALTLEN_AUTO_DIGEST_MAX
) {
70 ERR_raise(ERR_LIB_RSA
, RSA_R_SLEN_CHECK_FAILED
);
74 MSBits
= (BN_num_bits(rsa
->n
) - 1) & 0x7;
75 emLen
= RSA_size(rsa
);
76 if (EM
[0] & (0xFF << MSBits
)) {
77 ERR_raise(ERR_LIB_RSA
, RSA_R_FIRST_OCTET_INVALID
);
84 if (emLen
< hLen
+ 2) {
85 ERR_raise(ERR_LIB_RSA
, RSA_R_DATA_TOO_LARGE
);
88 if (sLen
== RSA_PSS_SALTLEN_MAX
) {
89 sLen
= emLen
- hLen
- 2;
90 } else if (sLen
> emLen
- hLen
- 2) { /* sLen can be small negative */
91 ERR_raise(ERR_LIB_RSA
, RSA_R_DATA_TOO_LARGE
);
94 if (EM
[emLen
- 1] != 0xbc) {
95 ERR_raise(ERR_LIB_RSA
, RSA_R_LAST_OCTET_INVALID
);
98 maskedDBLen
= emLen
- hLen
- 1;
100 DB
= OPENSSL_malloc(maskedDBLen
);
103 if (PKCS1_MGF1(DB
, maskedDBLen
, H
, hLen
, mgf1Hash
) < 0)
105 for (i
= 0; i
< maskedDBLen
; i
++)
108 DB
[0] &= 0xFF >> (8 - MSBits
);
109 for (i
= 0; DB
[i
] == 0 && i
< (maskedDBLen
- 1); i
++) ;
110 if (DB
[i
++] != 0x1) {
111 ERR_raise(ERR_LIB_RSA
, RSA_R_SLEN_RECOVERY_FAILED
);
114 if (sLen
!= RSA_PSS_SALTLEN_AUTO
115 && sLen
!= RSA_PSS_SALTLEN_AUTO_DIGEST_MAX
116 && (maskedDBLen
- i
) != sLen
) {
117 ERR_raise_data(ERR_LIB_RSA
, RSA_R_SLEN_CHECK_FAILED
,
118 "expected: %d retrieved: %d", sLen
,
122 if (!EVP_DigestInit_ex(ctx
, Hash
, NULL
)
123 || !EVP_DigestUpdate(ctx
, zeroes
, sizeof(zeroes
))
124 || !EVP_DigestUpdate(ctx
, mHash
, hLen
))
126 if (maskedDBLen
- i
) {
127 if (!EVP_DigestUpdate(ctx
, DB
+ i
, maskedDBLen
- i
))
130 if (!EVP_DigestFinal_ex(ctx
, H_
, NULL
))
132 if (memcmp(H_
, H
, hLen
)) {
133 ERR_raise(ERR_LIB_RSA
, RSA_R_BAD_SIGNATURE
);
141 EVP_MD_CTX_free(ctx
);
147 int RSA_padding_add_PKCS1_PSS(RSA
*rsa
, unsigned char *EM
,
148 const unsigned char *mHash
,
149 const EVP_MD
*Hash
, int sLen
)
151 return RSA_padding_add_PKCS1_PSS_mgf1(rsa
, EM
, mHash
, Hash
, NULL
, sLen
);
154 int RSA_padding_add_PKCS1_PSS_mgf1(RSA
*rsa
, unsigned char *EM
,
155 const unsigned char *mHash
,
156 const EVP_MD
*Hash
, const EVP_MD
*mgf1Hash
,
161 int hLen
, maskedDBLen
, MSBits
, emLen
;
162 unsigned char *H
, *salt
= NULL
, *p
;
163 EVP_MD_CTX
*ctx
= NULL
;
166 if (mgf1Hash
== NULL
)
169 hLen
= EVP_MD_get_size(Hash
);
173 * Negative sLen has special meanings:
175 * -2 salt length is maximized
176 * -3 same as above (on signing)
177 * -4 salt length is min(hLen, maximum salt length)
180 /* FIPS 186-4 section 5 "The RSA Digital Signature Algorithm", subsection
181 * 5.5 "PKCS #1" says: "For RSASSA-PSS […] the length (in bytes) of the
182 * salt (sLen) shall satisfy 0 <= sLen <= hLen, where hLen is the length of
183 * the hash function output block (in bytes)."
185 * Provide a way to use at most the digest length, so that the default does
186 * not violate FIPS 186-4. */
187 if (sLen
== RSA_PSS_SALTLEN_DIGEST
) {
189 } else if (sLen
== RSA_PSS_SALTLEN_MAX_SIGN
190 || sLen
== RSA_PSS_SALTLEN_AUTO
) {
191 sLen
= RSA_PSS_SALTLEN_MAX
;
192 } else if (sLen
== RSA_PSS_SALTLEN_AUTO_DIGEST_MAX
) {
193 sLen
= RSA_PSS_SALTLEN_MAX
;
195 } else if (sLen
< RSA_PSS_SALTLEN_AUTO_DIGEST_MAX
) {
196 ERR_raise(ERR_LIB_RSA
, RSA_R_SLEN_CHECK_FAILED
);
200 MSBits
= (BN_num_bits(rsa
->n
) - 1) & 0x7;
201 emLen
= RSA_size(rsa
);
206 if (emLen
< hLen
+ 2) {
207 ERR_raise(ERR_LIB_RSA
, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE
);
210 if (sLen
== RSA_PSS_SALTLEN_MAX
) {
211 sLen
= emLen
- hLen
- 2;
212 if (sLenMax
>= 0 && sLen
> sLenMax
)
214 } else if (sLen
> emLen
- hLen
- 2) {
215 ERR_raise(ERR_LIB_RSA
, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE
);
219 salt
= OPENSSL_malloc(sLen
);
222 if (RAND_bytes_ex(rsa
->libctx
, salt
, sLen
, 0) <= 0)
225 maskedDBLen
= emLen
- hLen
- 1;
226 H
= EM
+ maskedDBLen
;
227 ctx
= EVP_MD_CTX_new();
230 if (!EVP_DigestInit_ex(ctx
, Hash
, NULL
)
231 || !EVP_DigestUpdate(ctx
, zeroes
, sizeof(zeroes
))
232 || !EVP_DigestUpdate(ctx
, mHash
, hLen
))
234 if (sLen
&& !EVP_DigestUpdate(ctx
, salt
, sLen
))
236 if (!EVP_DigestFinal_ex(ctx
, H
, NULL
))
239 /* Generate dbMask in place then perform XOR on it */
240 if (PKCS1_MGF1(EM
, maskedDBLen
, H
, hLen
, mgf1Hash
))
246 * Initial PS XORs with all zeroes which is a NOP so just update pointer.
247 * Note from a test above this value is guaranteed to be non-negative.
249 p
+= emLen
- sLen
- hLen
- 2;
252 for (i
= 0; i
< sLen
; i
++)
256 EM
[0] &= 0xFF >> (8 - MSBits
);
258 /* H is already in place so just set final 0xbc */
260 EM
[emLen
- 1] = 0xbc;
265 EVP_MD_CTX_free(ctx
);
266 OPENSSL_clear_free(salt
, (size_t)sLen
); /* salt != NULL implies sLen > 0 */
273 * The defaults for PSS restrictions are defined in RFC 8017, A.2.3 RSASSA-PSS
274 * (https://tools.ietf.org/html/rfc8017#appendix-A.2.3):
276 * If the default values of the hashAlgorithm, maskGenAlgorithm, and
277 * trailerField fields of RSASSA-PSS-params are used, then the algorithm
278 * identifier will have the following value:
280 * rSASSA-PSS-Default-Identifier RSASSA-AlgorithmIdentifier ::= {
281 * algorithm id-RSASSA-PSS,
282 * parameters RSASSA-PSS-params : {
283 * hashAlgorithm sha1,
284 * maskGenAlgorithm mgf1SHA1,
286 * trailerField trailerFieldBC
290 * RSASSA-AlgorithmIdentifier ::= AlgorithmIdentifier {
294 static const RSA_PSS_PARAMS_30 default_RSASSA_PSS_params
= {
295 NID_sha1
, /* default hashAlgorithm */
297 NID_mgf1
, /* default maskGenAlgorithm */
298 NID_sha1
/* default MGF1 hash */
300 20, /* default saltLength */
301 1 /* default trailerField (0xBC) */
304 int ossl_rsa_pss_params_30_set_defaults(RSA_PSS_PARAMS_30
*rsa_pss_params
)
306 if (rsa_pss_params
== NULL
)
308 *rsa_pss_params
= default_RSASSA_PSS_params
;
312 int ossl_rsa_pss_params_30_is_unrestricted(const RSA_PSS_PARAMS_30
*rsa_pss_params
)
314 static RSA_PSS_PARAMS_30 pss_params_cmp
= { 0, };
316 return rsa_pss_params
== NULL
317 || memcmp(rsa_pss_params
, &pss_params_cmp
,
318 sizeof(*rsa_pss_params
)) == 0;
321 int ossl_rsa_pss_params_30_copy(RSA_PSS_PARAMS_30
*to
,
322 const RSA_PSS_PARAMS_30
*from
)
324 memcpy(to
, from
, sizeof(*to
));
328 int ossl_rsa_pss_params_30_set_hashalg(RSA_PSS_PARAMS_30
*rsa_pss_params
,
331 if (rsa_pss_params
== NULL
)
333 rsa_pss_params
->hash_algorithm_nid
= hashalg_nid
;
337 int ossl_rsa_pss_params_30_set_maskgenhashalg(RSA_PSS_PARAMS_30
*rsa_pss_params
,
338 int maskgenhashalg_nid
)
340 if (rsa_pss_params
== NULL
)
342 rsa_pss_params
->mask_gen
.hash_algorithm_nid
= maskgenhashalg_nid
;
346 int ossl_rsa_pss_params_30_set_saltlen(RSA_PSS_PARAMS_30
*rsa_pss_params
,
349 if (rsa_pss_params
== NULL
)
351 rsa_pss_params
->salt_len
= saltlen
;
355 int ossl_rsa_pss_params_30_set_trailerfield(RSA_PSS_PARAMS_30
*rsa_pss_params
,
358 if (rsa_pss_params
== NULL
)
360 rsa_pss_params
->trailer_field
= trailerfield
;
364 int ossl_rsa_pss_params_30_hashalg(const RSA_PSS_PARAMS_30
*rsa_pss_params
)
366 if (rsa_pss_params
== NULL
)
367 return default_RSASSA_PSS_params
.hash_algorithm_nid
;
368 return rsa_pss_params
->hash_algorithm_nid
;
371 int ossl_rsa_pss_params_30_maskgenalg(const RSA_PSS_PARAMS_30
*rsa_pss_params
)
373 if (rsa_pss_params
== NULL
)
374 return default_RSASSA_PSS_params
.mask_gen
.algorithm_nid
;
375 return rsa_pss_params
->mask_gen
.algorithm_nid
;
378 int ossl_rsa_pss_params_30_maskgenhashalg(const RSA_PSS_PARAMS_30
*rsa_pss_params
)
380 if (rsa_pss_params
== NULL
)
381 return default_RSASSA_PSS_params
.hash_algorithm_nid
;
382 return rsa_pss_params
->mask_gen
.hash_algorithm_nid
;
385 int ossl_rsa_pss_params_30_saltlen(const RSA_PSS_PARAMS_30
*rsa_pss_params
)
387 if (rsa_pss_params
== NULL
)
388 return default_RSASSA_PSS_params
.salt_len
;
389 return rsa_pss_params
->salt_len
;
392 int ossl_rsa_pss_params_30_trailerfield(const RSA_PSS_PARAMS_30
*rsa_pss_params
)
394 if (rsa_pss_params
== NULL
)
395 return default_RSASSA_PSS_params
.trailer_field
;
396 return rsa_pss_params
->trailer_field
;
399 #if defined(_MSC_VER)
400 # pragma optimize("",on)