1 /*
2 * Copyright 2005-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9
10 /*
11 * RSA low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdio.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"
24
25 static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
26
27 #if defined(_MSC_VER) && defined(_ARM_)
28 # pragma optimize("g", off)
29 #endif
30
RSA_verify_PKCS1_PSS(RSA * rsa,const unsigned char * mHash,const EVP_MD * Hash,const unsigned char * EM,int sLen)31 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
32 const EVP_MD *Hash, const unsigned char *EM,
33 int sLen)
34 {
35 return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
36 }
37
RSA_verify_PKCS1_PSS_mgf1(RSA * rsa,const unsigned char * mHash,const EVP_MD * Hash,const EVP_MD * mgf1Hash,const unsigned char * EM,int 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)
41 {
42 int i;
43 int ret = 0;
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];
49
50 if (ctx == NULL)
51 goto err;
52
53 if (mgf1Hash == NULL)
54 mgf1Hash = Hash;
55
56 hLen = EVP_MD_get_size(Hash);
57 if (hLen < 0)
58 goto err;
59 /*-
60 * Negative sLen has special meanings:
61 * -1 sLen == hLen
62 * -2 salt length is autorecovered from signature
63 * -3 salt length is maximized
64 * -N reserved
65 */
66 if (sLen == RSA_PSS_SALTLEN_DIGEST) {
67 sLen = hLen;
68 } else if (sLen < RSA_PSS_SALTLEN_MAX) {
69 ERR_raise(ERR_LIB_RSA, RSA_R_SLEN_CHECK_FAILED);
70 goto err;
71 }
72
73 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
74 emLen = RSA_size(rsa);
75 if (EM[0] & (0xFF << MSBits)) {
76 ERR_raise(ERR_LIB_RSA, RSA_R_FIRST_OCTET_INVALID);
77 goto err;
78 }
79 if (MSBits == 0) {
80 EM++;
81 emLen--;
82 }
83 if (emLen < hLen + 2) {
84 ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE);
85 goto err;
86 }
87 if (sLen == RSA_PSS_SALTLEN_MAX) {
88 sLen = emLen - hLen - 2;
89 } else if (sLen > emLen - hLen - 2) { /* sLen can be small negative */
90 ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE);
91 goto err;
92 }
93 if (EM[emLen - 1] != 0xbc) {
94 ERR_raise(ERR_LIB_RSA, RSA_R_LAST_OCTET_INVALID);
95 goto err;
96 }
97 maskedDBLen = emLen - hLen - 1;
98 H = EM + maskedDBLen;
99 DB = OPENSSL_malloc(maskedDBLen);
100 if (DB == NULL) {
101 ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
102 goto err;
103 }
104 if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
105 goto err;
106 for (i = 0; i < maskedDBLen; i++)
107 DB[i] ^= EM[i];
108 if (MSBits)
109 DB[0] &= 0xFF >> (8 - MSBits);
110 for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ;
111 if (DB[i++] != 0x1) {
112 ERR_raise(ERR_LIB_RSA, RSA_R_SLEN_RECOVERY_FAILED);
113 goto err;
114 }
115 if (sLen != RSA_PSS_SALTLEN_AUTO && (maskedDBLen - i) != sLen) {
116 ERR_raise_data(ERR_LIB_RSA, RSA_R_SLEN_CHECK_FAILED,
117 "expected: %d retrieved: %d", sLen,
118 maskedDBLen - i);
119 goto err;
120 }
121 if (!EVP_DigestInit_ex(ctx, Hash, NULL)
122 || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
123 || !EVP_DigestUpdate(ctx, mHash, hLen))
124 goto err;
125 if (maskedDBLen - i) {
126 if (!EVP_DigestUpdate(ctx, DB + i, maskedDBLen - i))
127 goto err;
128 }
129 if (!EVP_DigestFinal_ex(ctx, H_, NULL))
130 goto err;
131 if (memcmp(H_, H, hLen)) {
132 ERR_raise(ERR_LIB_RSA, RSA_R_BAD_SIGNATURE);
133 ret = 0;
134 } else {
135 ret = 1;
136 }
137
138 err:
139 OPENSSL_free(DB);
140 EVP_MD_CTX_free(ctx);
141
142 return ret;
143
144 }
145
RSA_padding_add_PKCS1_PSS(RSA * rsa,unsigned char * EM,const unsigned char * mHash,const EVP_MD * Hash,int sLen)146 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
147 const unsigned char *mHash,
148 const EVP_MD *Hash, int sLen)
149 {
150 return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
151 }
152
RSA_padding_add_PKCS1_PSS_mgf1(RSA * rsa,unsigned char * EM,const unsigned char * mHash,const EVP_MD * Hash,const EVP_MD * mgf1Hash,int sLen)153 int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
154 const unsigned char *mHash,
155 const EVP_MD *Hash, const EVP_MD *mgf1Hash,
156 int sLen)
157 {
158 int i;
159 int ret = 0;
160 int hLen, maskedDBLen, MSBits, emLen;
161 unsigned char *H, *salt = NULL, *p;
162 EVP_MD_CTX *ctx = NULL;
163
164 if (mgf1Hash == NULL)
165 mgf1Hash = Hash;
166
167 hLen = EVP_MD_get_size(Hash);
168 if (hLen < 0)
169 goto err;
170 /*-
171 * Negative sLen has special meanings:
172 * -1 sLen == hLen
173 * -2 salt length is maximized
174 * -3 same as above (on signing)
175 * -N reserved
176 */
177 if (sLen == RSA_PSS_SALTLEN_DIGEST) {
178 sLen = hLen;
179 } else if (sLen == RSA_PSS_SALTLEN_MAX_SIGN) {
180 sLen = RSA_PSS_SALTLEN_MAX;
181 } else if (sLen < RSA_PSS_SALTLEN_MAX) {
182 ERR_raise(ERR_LIB_RSA, RSA_R_SLEN_CHECK_FAILED);
183 goto err;
184 }
185
186 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
187 emLen = RSA_size(rsa);
188 if (MSBits == 0) {
189 *EM++ = 0;
190 emLen--;
191 }
192 if (emLen < hLen + 2) {
193 ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
194 goto err;
195 }
196 if (sLen == RSA_PSS_SALTLEN_MAX) {
197 sLen = emLen - hLen - 2;
198 } else if (sLen > emLen - hLen - 2) {
199 ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
200 goto err;
201 }
202 if (sLen > 0) {
203 salt = OPENSSL_malloc(sLen);
204 if (salt == NULL) {
205 ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
206 goto err;
207 }
208 if (RAND_bytes_ex(rsa->libctx, salt, sLen, 0) <= 0)
209 goto err;
210 }
211 maskedDBLen = emLen - hLen - 1;
212 H = EM + maskedDBLen;
213 ctx = EVP_MD_CTX_new();
214 if (ctx == NULL)
215 goto err;
216 if (!EVP_DigestInit_ex(ctx, Hash, NULL)
217 || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
218 || !EVP_DigestUpdate(ctx, mHash, hLen))
219 goto err;
220 if (sLen && !EVP_DigestUpdate(ctx, salt, sLen))
221 goto err;
222 if (!EVP_DigestFinal_ex(ctx, H, NULL))
223 goto err;
224
225 /* Generate dbMask in place then perform XOR on it */
226 if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
227 goto err;
228
229 p = EM;
230
231 /*
232 * Initial PS XORs with all zeroes which is a NOP so just update pointer.
233 * Note from a test above this value is guaranteed to be non-negative.
234 */
235 p += emLen - sLen - hLen - 2;
236 *p++ ^= 0x1;
237 if (sLen > 0) {
238 for (i = 0; i < sLen; i++)
239 *p++ ^= salt[i];
240 }
241 if (MSBits)
242 EM[0] &= 0xFF >> (8 - MSBits);
243
244 /* H is already in place so just set final 0xbc */
245
246 EM[emLen - 1] = 0xbc;
247
248 ret = 1;
249
250 err:
251 EVP_MD_CTX_free(ctx);
252 OPENSSL_clear_free(salt, (size_t)sLen); /* salt != NULL implies sLen > 0 */
253
254 return ret;
255
256 }
257
258 /*
259 * The defaults for PSS restrictions are defined in RFC 8017, A.2.3 RSASSA-PSS
260 * (https://tools.ietf.org/html/rfc8017#appendix-A.2.3):
261 *
262 * If the default values of the hashAlgorithm, maskGenAlgorithm, and
263 * trailerField fields of RSASSA-PSS-params are used, then the algorithm
264 * identifier will have the following value:
265 *
266 * rSASSA-PSS-Default-Identifier RSASSA-AlgorithmIdentifier ::= {
267 * algorithm id-RSASSA-PSS,
268 * parameters RSASSA-PSS-params : {
269 * hashAlgorithm sha1,
270 * maskGenAlgorithm mgf1SHA1,
271 * saltLength 20,
272 * trailerField trailerFieldBC
273 * }
274 * }
275 *
276 * RSASSA-AlgorithmIdentifier ::= AlgorithmIdentifier {
277 * {PKCS1Algorithms}
278 * }
279 */
280 static const RSA_PSS_PARAMS_30 default_RSASSA_PSS_params = {
281 NID_sha1, /* default hashAlgorithm */
282 {
283 NID_mgf1, /* default maskGenAlgorithm */
284 NID_sha1 /* default MGF1 hash */
285 },
286 20, /* default saltLength */
287 1 /* default trailerField (0xBC) */
288 };
289
ossl_rsa_pss_params_30_set_defaults(RSA_PSS_PARAMS_30 * rsa_pss_params)290 int ossl_rsa_pss_params_30_set_defaults(RSA_PSS_PARAMS_30 *rsa_pss_params)
291 {
292 if (rsa_pss_params == NULL)
293 return 0;
294 *rsa_pss_params = default_RSASSA_PSS_params;
295 return 1;
296 }
297
ossl_rsa_pss_params_30_is_unrestricted(const RSA_PSS_PARAMS_30 * rsa_pss_params)298 int ossl_rsa_pss_params_30_is_unrestricted(const RSA_PSS_PARAMS_30 *rsa_pss_params)
299 {
300 static RSA_PSS_PARAMS_30 pss_params_cmp = { 0, };
301
302 return rsa_pss_params == NULL
303 || memcmp(rsa_pss_params, &pss_params_cmp,
304 sizeof(*rsa_pss_params)) == 0;
305 }
306
ossl_rsa_pss_params_30_copy(RSA_PSS_PARAMS_30 * to,const RSA_PSS_PARAMS_30 * from)307 int ossl_rsa_pss_params_30_copy(RSA_PSS_PARAMS_30 *to,
308 const RSA_PSS_PARAMS_30 *from)
309 {
310 memcpy(to, from, sizeof(*to));
311 return 1;
312 }
313
ossl_rsa_pss_params_30_set_hashalg(RSA_PSS_PARAMS_30 * rsa_pss_params,int hashalg_nid)314 int ossl_rsa_pss_params_30_set_hashalg(RSA_PSS_PARAMS_30 *rsa_pss_params,
315 int hashalg_nid)
316 {
317 if (rsa_pss_params == NULL)
318 return 0;
319 rsa_pss_params->hash_algorithm_nid = hashalg_nid;
320 return 1;
321 }
322
ossl_rsa_pss_params_30_set_maskgenalg(RSA_PSS_PARAMS_30 * rsa_pss_params,int maskgenalg_nid)323 int ossl_rsa_pss_params_30_set_maskgenalg(RSA_PSS_PARAMS_30 *rsa_pss_params,
324 int maskgenalg_nid)
325 {
326 if (rsa_pss_params == NULL)
327 return 0;
328 rsa_pss_params->mask_gen.algorithm_nid = maskgenalg_nid;
329 return 1;
330 }
331
ossl_rsa_pss_params_30_set_maskgenhashalg(RSA_PSS_PARAMS_30 * rsa_pss_params,int maskgenhashalg_nid)332 int ossl_rsa_pss_params_30_set_maskgenhashalg(RSA_PSS_PARAMS_30 *rsa_pss_params,
333 int maskgenhashalg_nid)
334 {
335 if (rsa_pss_params == NULL)
336 return 0;
337 rsa_pss_params->mask_gen.hash_algorithm_nid = maskgenhashalg_nid;
338 return 1;
339 }
340
ossl_rsa_pss_params_30_set_saltlen(RSA_PSS_PARAMS_30 * rsa_pss_params,int saltlen)341 int ossl_rsa_pss_params_30_set_saltlen(RSA_PSS_PARAMS_30 *rsa_pss_params,
342 int saltlen)
343 {
344 if (rsa_pss_params == NULL)
345 return 0;
346 rsa_pss_params->salt_len = saltlen;
347 return 1;
348 }
349
ossl_rsa_pss_params_30_set_trailerfield(RSA_PSS_PARAMS_30 * rsa_pss_params,int trailerfield)350 int ossl_rsa_pss_params_30_set_trailerfield(RSA_PSS_PARAMS_30 *rsa_pss_params,
351 int trailerfield)
352 {
353 if (rsa_pss_params == NULL)
354 return 0;
355 rsa_pss_params->trailer_field = trailerfield;
356 return 1;
357 }
358
ossl_rsa_pss_params_30_hashalg(const RSA_PSS_PARAMS_30 * rsa_pss_params)359 int ossl_rsa_pss_params_30_hashalg(const RSA_PSS_PARAMS_30 *rsa_pss_params)
360 {
361 if (rsa_pss_params == NULL)
362 return default_RSASSA_PSS_params.hash_algorithm_nid;
363 return rsa_pss_params->hash_algorithm_nid;
364 }
365
ossl_rsa_pss_params_30_maskgenalg(const RSA_PSS_PARAMS_30 * rsa_pss_params)366 int ossl_rsa_pss_params_30_maskgenalg(const RSA_PSS_PARAMS_30 *rsa_pss_params)
367 {
368 if (rsa_pss_params == NULL)
369 return default_RSASSA_PSS_params.mask_gen.algorithm_nid;
370 return rsa_pss_params->mask_gen.algorithm_nid;
371 }
372
ossl_rsa_pss_params_30_maskgenhashalg(const RSA_PSS_PARAMS_30 * rsa_pss_params)373 int ossl_rsa_pss_params_30_maskgenhashalg(const RSA_PSS_PARAMS_30 *rsa_pss_params)
374 {
375 if (rsa_pss_params == NULL)
376 return default_RSASSA_PSS_params.hash_algorithm_nid;
377 return rsa_pss_params->mask_gen.hash_algorithm_nid;
378 }
379
ossl_rsa_pss_params_30_saltlen(const RSA_PSS_PARAMS_30 * rsa_pss_params)380 int ossl_rsa_pss_params_30_saltlen(const RSA_PSS_PARAMS_30 *rsa_pss_params)
381 {
382 if (rsa_pss_params == NULL)
383 return default_RSASSA_PSS_params.salt_len;
384 return rsa_pss_params->salt_len;
385 }
386
ossl_rsa_pss_params_30_trailerfield(const RSA_PSS_PARAMS_30 * rsa_pss_params)387 int ossl_rsa_pss_params_30_trailerfield(const RSA_PSS_PARAMS_30 *rsa_pss_params)
388 {
389 if (rsa_pss_params == NULL)
390 return default_RSASSA_PSS_params.trailer_field;
391 return rsa_pss_params->trailer_field;
392 }
393
394 #if defined(_MSC_VER)
395 # pragma optimize("",on)
396 #endif
397