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2039c421 | 1 | /* |
33388b44 | 2 | * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved. |
0f113f3e | 3 | * |
2a7b6f39 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
2039c421 RS |
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 | |
d02b48c6 RE |
8 | */ |
9 | ||
0f113f3e MC |
10 | /* |
11 | * NB: these functions have been "upgraded", the deprecated versions (which | |
12 | * are compatibility wrappers using these functions) are in rsa_depr.c. - | |
13 | * Geoff | |
e9224c71 GT |
14 | */ |
15 | ||
c5f87134 P |
16 | /* |
17 | * RSA low level APIs are deprecated for public use, but still ok for | |
18 | * internal use. | |
19 | */ | |
20 | #include "internal/deprecated.h" | |
21 | ||
d02b48c6 RE |
22 | #include <stdio.h> |
23 | #include <time.h> | |
b39fc560 | 24 | #include "internal/cryptlib.h" |
ec577822 | 25 | #include <openssl/bn.h> |
47c239c6 | 26 | #include <openssl/self_test.h> |
706457b7 | 27 | #include "rsa_local.h" |
d02b48c6 | 28 | |
47c239c6 SL |
29 | static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg); |
30 | static int rsa_keygen(OPENSSL_CTX *libctx, RSA *rsa, int bits, int primes, | |
31 | BIGNUM *e_value, BN_GENCB *cb, int pairwise_test); | |
2814c629 | 32 | |
0f113f3e MC |
33 | /* |
34 | * NB: this wrapper would normally be placed in rsa_lib.c and the static | |
35 | * implementation would probably be in rsa_eay.c. Nonetheless, is kept here | |
36 | * so that we don't introduce a new linker dependency. Eg. any application | |
37 | * that wasn't previously linking object code related to key-generation won't | |
38 | * have to now just because key-generation is part of RSA_METHOD. | |
39 | */ | |
bcfea9fb | 40 | int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) |
0f113f3e | 41 | { |
665d899f | 42 | if (rsa->meth->rsa_keygen != NULL) |
0f113f3e | 43 | return rsa->meth->rsa_keygen(rsa, bits, e_value, cb); |
665d899f PY |
44 | |
45 | return RSA_generate_multi_prime_key(rsa, bits, RSA_DEFAULT_PRIME_NUM, | |
46 | e_value, cb); | |
0f113f3e MC |
47 | } |
48 | ||
665d899f PY |
49 | int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes, |
50 | BIGNUM *e_value, BN_GENCB *cb) | |
51 | { | |
f844f9eb | 52 | #ifndef FIPS_MODULE |
665d899f | 53 | /* multi-prime is only supported with the builtin key generation */ |
e44480cc | 54 | if (rsa->meth->rsa_multi_prime_keygen != NULL) { |
665d899f PY |
55 | return rsa->meth->rsa_multi_prime_keygen(rsa, bits, primes, |
56 | e_value, cb); | |
e44480cc AP |
57 | } else if (rsa->meth->rsa_keygen != NULL) { |
58 | /* | |
59 | * However, if rsa->meth implements only rsa_keygen, then we | |
60 | * have to honour it in 2-prime case and assume that it wouldn't | |
61 | * know what to do with multi-prime key generated by builtin | |
62 | * subroutine... | |
63 | */ | |
64 | if (primes == 2) | |
65 | return rsa->meth->rsa_keygen(rsa, bits, e_value, cb); | |
66 | else | |
67 | return 0; | |
68 | } | |
f844f9eb | 69 | #endif /* FIPS_MODULE */ |
47c239c6 | 70 | return rsa_keygen(NULL, rsa, bits, primes, e_value, cb, 0); |
665d899f PY |
71 | } |
72 | ||
47c239c6 SL |
73 | static int rsa_keygen(OPENSSL_CTX *libctx, RSA *rsa, int bits, int primes, |
74 | BIGNUM *e_value, BN_GENCB *cb, int pairwise_test) | |
0f113f3e | 75 | { |
47c239c6 | 76 | int ok = -1; |
f844f9eb | 77 | #ifdef FIPS_MODULE |
8240d5fa SL |
78 | if (primes != 2) |
79 | return 0; | |
47c239c6 SL |
80 | ok = rsa_sp800_56b_generate_key(rsa, bits, e_value, cb); |
81 | pairwise_test = 1; /* FIPS MODE needs to always run the pairwise test */ | |
8240d5fa | 82 | #else |
665d899f | 83 | BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *tmp, *prime; |
47c239c6 | 84 | int n = 0, bitsr[RSA_MAX_PRIME_NUM], bitse = 0; |
665d899f PY |
85 | int i = 0, quo = 0, rmd = 0, adj = 0, retries = 0; |
86 | RSA_PRIME_INFO *pinfo = NULL; | |
87 | STACK_OF(RSA_PRIME_INFO) *prime_infos = NULL; | |
0f113f3e | 88 | BN_CTX *ctx = NULL; |
665d899f | 89 | BN_ULONG bitst = 0; |
8db7946e | 90 | unsigned long error = 0; |
665d899f | 91 | |
cac19d19 | 92 | if (bits < RSA_MIN_MODULUS_BITS) { |
69795831 | 93 | ok = 0; /* we set our own err */ |
47c239c6 | 94 | RSAerr(0, RSA_R_KEY_SIZE_TOO_SMALL); |
69795831 RS |
95 | goto err; |
96 | } | |
97 | ||
3bded9cd AP |
98 | if (primes < RSA_DEFAULT_PRIME_NUM || primes > rsa_multip_cap(bits)) { |
99 | ok = 0; /* we set our own err */ | |
47c239c6 | 100 | RSAerr(0, RSA_R_KEY_PRIME_NUM_INVALID); |
665d899f PY |
101 | goto err; |
102 | } | |
103 | ||
0f113f3e MC |
104 | ctx = BN_CTX_new(); |
105 | if (ctx == NULL) | |
106 | goto err; | |
107 | BN_CTX_start(ctx); | |
108 | r0 = BN_CTX_get(ctx); | |
109 | r1 = BN_CTX_get(ctx); | |
110 | r2 = BN_CTX_get(ctx); | |
665d899f PY |
111 | if (r2 == NULL) |
112 | goto err; | |
113 | ||
114 | /* divide bits into 'primes' pieces evenly */ | |
115 | quo = bits / primes; | |
116 | rmd = bits % primes; | |
117 | ||
665d899f PY |
118 | for (i = 0; i < primes; i++) |
119 | bitsr[i] = (i < rmd) ? quo + 1 : quo; | |
0f113f3e | 120 | |
29be6023 RL |
121 | rsa->dirty_cnt++; |
122 | ||
0f113f3e MC |
123 | /* We need the RSA components non-NULL */ |
124 | if (!rsa->n && ((rsa->n = BN_new()) == NULL)) | |
125 | goto err; | |
74924dcb | 126 | if (!rsa->d && ((rsa->d = BN_secure_new()) == NULL)) |
0f113f3e MC |
127 | goto err; |
128 | if (!rsa->e && ((rsa->e = BN_new()) == NULL)) | |
129 | goto err; | |
74924dcb | 130 | if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL)) |
0f113f3e | 131 | goto err; |
74924dcb | 132 | if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL)) |
0f113f3e | 133 | goto err; |
74924dcb | 134 | if (!rsa->dmp1 && ((rsa->dmp1 = BN_secure_new()) == NULL)) |
0f113f3e | 135 | goto err; |
74924dcb | 136 | if (!rsa->dmq1 && ((rsa->dmq1 = BN_secure_new()) == NULL)) |
0f113f3e | 137 | goto err; |
74924dcb | 138 | if (!rsa->iqmp && ((rsa->iqmp = BN_secure_new()) == NULL)) |
0f113f3e MC |
139 | goto err; |
140 | ||
665d899f PY |
141 | /* initialize multi-prime components */ |
142 | if (primes > RSA_DEFAULT_PRIME_NUM) { | |
143 | rsa->version = RSA_ASN1_VERSION_MULTI; | |
144 | prime_infos = sk_RSA_PRIME_INFO_new_reserve(NULL, primes - 2); | |
145 | if (prime_infos == NULL) | |
146 | goto err; | |
147 | if (rsa->prime_infos != NULL) { | |
148 | /* could this happen? */ | |
149 | sk_RSA_PRIME_INFO_pop_free(rsa->prime_infos, rsa_multip_info_free); | |
150 | } | |
151 | rsa->prime_infos = prime_infos; | |
152 | ||
153 | /* prime_info from 2 to |primes| -1 */ | |
154 | for (i = 2; i < primes; i++) { | |
155 | pinfo = rsa_multip_info_new(); | |
156 | if (pinfo == NULL) | |
157 | goto err; | |
158 | (void)sk_RSA_PRIME_INFO_push(prime_infos, pinfo); | |
159 | } | |
160 | } | |
161 | ||
78e09b53 RS |
162 | if (BN_copy(rsa->e, e_value) == NULL) |
163 | goto err; | |
0f113f3e | 164 | |
665d899f PY |
165 | /* generate p, q and other primes (if any) */ |
166 | for (i = 0; i < primes; i++) { | |
167 | adj = 0; | |
168 | retries = 0; | |
169 | ||
170 | if (i == 0) { | |
171 | prime = rsa->p; | |
172 | } else if (i == 1) { | |
173 | prime = rsa->q; | |
174 | } else { | |
175 | pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); | |
176 | prime = pinfo->r; | |
177 | } | |
54f007af | 178 | BN_set_flags(prime, BN_FLG_CONSTTIME); |
665d899f PY |
179 | |
180 | for (;;) { | |
181 | redo: | |
182 | if (!BN_generate_prime_ex(prime, bitsr[i] + adj, 0, NULL, NULL, cb)) | |
183 | goto err; | |
184 | /* | |
185 | * prime should not be equal to p, q, r_3... | |
186 | * (those primes prior to this one) | |
187 | */ | |
188 | { | |
189 | int j; | |
190 | ||
191 | for (j = 0; j < i; j++) { | |
192 | BIGNUM *prev_prime; | |
193 | ||
194 | if (j == 0) | |
195 | prev_prime = rsa->p; | |
196 | else if (j == 1) | |
197 | prev_prime = rsa->q; | |
198 | else | |
199 | prev_prime = sk_RSA_PRIME_INFO_value(prime_infos, | |
200 | j - 2)->r; | |
201 | ||
202 | if (!BN_cmp(prime, prev_prime)) { | |
203 | goto redo; | |
204 | } | |
205 | } | |
206 | } | |
207 | if (!BN_sub(r2, prime, BN_value_one())) | |
208 | goto err; | |
8db7946e SW |
209 | ERR_set_mark(); |
210 | BN_set_flags(r2, BN_FLG_CONSTTIME); | |
211 | if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) { | |
212 | /* GCD == 1 since inverse exists */ | |
665d899f | 213 | break; |
8db7946e SW |
214 | } |
215 | error = ERR_peek_last_error(); | |
216 | if (ERR_GET_LIB(error) == ERR_LIB_BN | |
217 | && ERR_GET_REASON(error) == BN_R_NO_INVERSE) { | |
218 | /* GCD != 1 */ | |
219 | ERR_pop_to_mark(); | |
220 | } else { | |
221 | goto err; | |
222 | } | |
665d899f PY |
223 | if (!BN_GENCB_call(cb, 2, n++)) |
224 | goto err; | |
225 | } | |
226 | ||
227 | bitse += bitsr[i]; | |
228 | ||
229 | /* calculate n immediately to see if it's sufficient */ | |
230 | if (i == 1) { | |
231 | /* we get at least 2 primes */ | |
232 | if (!BN_mul(r1, rsa->p, rsa->q, ctx)) | |
233 | goto err; | |
234 | } else if (i != 0) { | |
235 | /* modulus n = p * q * r_3 * r_4 ... */ | |
236 | if (!BN_mul(r1, rsa->n, prime, ctx)) | |
237 | goto err; | |
238 | } else { | |
239 | /* i == 0, do nothing */ | |
240 | if (!BN_GENCB_call(cb, 3, i)) | |
241 | goto err; | |
242 | continue; | |
243 | } | |
244 | /* | |
245 | * if |r1|, product of factors so far, is not as long as expected | |
246 | * (by checking the first 4 bits are less than 0x9 or greater than | |
247 | * 0xF). If so, re-generate the last prime. | |
248 | * | |
249 | * NOTE: This actually can't happen in two-prime case, because of | |
250 | * the way factors are generated. | |
251 | * | |
252 | * Besides, another consideration is, for multi-prime case, even the | |
253 | * length modulus is as long as expected, the modulus could start at | |
254 | * 0x8, which could be utilized to distinguish a multi-prime private | |
255 | * key by using the modulus in a certificate. This is also covered | |
256 | * by checking the length should not be less than 0x9. | |
257 | */ | |
258 | if (!BN_rshift(r2, r1, bitse - 4)) | |
0f113f3e | 259 | goto err; |
665d899f PY |
260 | bitst = BN_get_word(r2); |
261 | ||
262 | if (bitst < 0x9 || bitst > 0xF) { | |
263 | /* | |
264 | * For keys with more than 4 primes, we attempt longer factor to | |
265 | * meet length requirement. | |
266 | * | |
267 | * Otherwise, we just re-generate the prime with the same length. | |
268 | * | |
269 | * This strategy has the following goals: | |
270 | * | |
c2969ff6 | 271 | * 1. 1024-bit factors are efficient when using 3072 and 4096-bit key |
665d899f PY |
272 | * 2. stay the same logic with normal 2-prime key |
273 | */ | |
274 | bitse -= bitsr[i]; | |
275 | if (!BN_GENCB_call(cb, 2, n++)) | |
0f113f3e | 276 | goto err; |
665d899f PY |
277 | if (primes > 4) { |
278 | if (bitst < 0x9) | |
279 | adj++; | |
280 | else | |
281 | adj--; | |
282 | } else if (retries == 4) { | |
283 | /* | |
284 | * re-generate all primes from scratch, mainly used | |
285 | * in 4 prime case to avoid long loop. Max retry times | |
286 | * is set to 4. | |
287 | */ | |
288 | i = -1; | |
289 | bitse = 0; | |
290 | continue; | |
291 | } | |
292 | retries++; | |
293 | goto redo; | |
294 | } | |
295 | /* save product of primes for further use, for multi-prime only */ | |
296 | if (i > 1 && BN_copy(pinfo->pp, rsa->n) == NULL) | |
0f113f3e | 297 | goto err; |
665d899f | 298 | if (BN_copy(rsa->n, r1) == NULL) |
0f113f3e | 299 | goto err; |
665d899f | 300 | if (!BN_GENCB_call(cb, 3, i)) |
0f113f3e MC |
301 | goto err; |
302 | } | |
665d899f | 303 | |
0f113f3e MC |
304 | if (BN_cmp(rsa->p, rsa->q) < 0) { |
305 | tmp = rsa->p; | |
306 | rsa->p = rsa->q; | |
307 | rsa->q = tmp; | |
308 | } | |
309 | ||
0f113f3e | 310 | /* calculate d */ |
665d899f PY |
311 | |
312 | /* p - 1 */ | |
0f113f3e | 313 | if (!BN_sub(r1, rsa->p, BN_value_one())) |
665d899f PY |
314 | goto err; |
315 | /* q - 1 */ | |
0f113f3e | 316 | if (!BN_sub(r2, rsa->q, BN_value_one())) |
665d899f PY |
317 | goto err; |
318 | /* (p - 1)(q - 1) */ | |
0f113f3e | 319 | if (!BN_mul(r0, r1, r2, ctx)) |
665d899f PY |
320 | goto err; |
321 | /* multi-prime */ | |
322 | for (i = 2; i < primes; i++) { | |
323 | pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); | |
324 | /* save r_i - 1 to pinfo->d temporarily */ | |
325 | if (!BN_sub(pinfo->d, pinfo->r, BN_value_one())) | |
326 | goto err; | |
327 | if (!BN_mul(r0, r0, pinfo->d, ctx)) | |
328 | goto err; | |
329 | } | |
330 | ||
fd7d2520 | 331 | { |
5584f65a MC |
332 | BIGNUM *pr0 = BN_new(); |
333 | ||
334 | if (pr0 == NULL) | |
335 | goto err; | |
665d899f | 336 | |
5584f65a | 337 | BN_with_flags(pr0, r0, BN_FLG_CONSTTIME); |
fd7d2520 | 338 | if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) { |
5584f65a | 339 | BN_free(pr0); |
fd7d2520 MC |
340 | goto err; /* d */ |
341 | } | |
5584f65a MC |
342 | /* We MUST free pr0 before any further use of r0 */ |
343 | BN_free(pr0); | |
fd7d2520 | 344 | } |
0f113f3e | 345 | |
fd7d2520 | 346 | { |
5584f65a MC |
347 | BIGNUM *d = BN_new(); |
348 | ||
349 | if (d == NULL) | |
350 | goto err; | |
665d899f | 351 | |
5584f65a | 352 | BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); |
0f113f3e | 353 | |
665d899f PY |
354 | /* calculate d mod (p-1) and d mod (q - 1) */ |
355 | if (!BN_mod(rsa->dmp1, d, r1, ctx) | |
fd7d2520 | 356 | || !BN_mod(rsa->dmq1, d, r2, ctx)) { |
5584f65a | 357 | BN_free(d); |
fd7d2520 MC |
358 | goto err; |
359 | } | |
665d899f PY |
360 | |
361 | /* calculate CRT exponents */ | |
362 | for (i = 2; i < primes; i++) { | |
363 | pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); | |
364 | /* pinfo->d == r_i - 1 */ | |
365 | if (!BN_mod(pinfo->d, d, pinfo->d, ctx)) { | |
366 | BN_free(d); | |
367 | goto err; | |
368 | } | |
369 | } | |
370 | ||
5584f65a MC |
371 | /* We MUST free d before any further use of rsa->d */ |
372 | BN_free(d); | |
fd7d2520 MC |
373 | } |
374 | ||
375 | { | |
5584f65a MC |
376 | BIGNUM *p = BN_new(); |
377 | ||
378 | if (p == NULL) | |
379 | goto err; | |
380 | BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); | |
fd7d2520 MC |
381 | |
382 | /* calculate inverse of q mod p */ | |
fd7d2520 | 383 | if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) { |
5584f65a | 384 | BN_free(p); |
fd7d2520 MC |
385 | goto err; |
386 | } | |
665d899f PY |
387 | |
388 | /* calculate CRT coefficient for other primes */ | |
389 | for (i = 2; i < primes; i++) { | |
390 | pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); | |
391 | BN_with_flags(p, pinfo->r, BN_FLG_CONSTTIME); | |
392 | if (!BN_mod_inverse(pinfo->t, pinfo->pp, p, ctx)) { | |
393 | BN_free(p); | |
394 | goto err; | |
395 | } | |
396 | } | |
397 | ||
5584f65a MC |
398 | /* We MUST free p before any further use of rsa->p */ |
399 | BN_free(p); | |
fd7d2520 | 400 | } |
0f113f3e MC |
401 | |
402 | ok = 1; | |
403 | err: | |
0f113f3e | 404 | if (ok == -1) { |
47c239c6 | 405 | RSAerr(0, ERR_LIB_BN); |
0f113f3e MC |
406 | ok = 0; |
407 | } | |
ce1415ed | 408 | BN_CTX_end(ctx); |
23a1d5e9 | 409 | BN_CTX_free(ctx); |
f844f9eb | 410 | #endif /* FIPS_MODULE */ |
47c239c6 SL |
411 | |
412 | if (pairwise_test && ok > 0) { | |
413 | OSSL_CALLBACK *stcb = NULL; | |
414 | void *stcbarg = NULL; | |
415 | ||
416 | OSSL_SELF_TEST_get_callback(libctx, &stcb, &stcbarg); | |
417 | ok = rsa_keygen_pairwise_test(rsa, stcb, stcbarg); | |
418 | if (!ok) { | |
419 | /* Clear intermediate results */ | |
420 | BN_clear_free(rsa->d); | |
421 | BN_clear_free(rsa->p); | |
422 | BN_clear_free(rsa->q); | |
423 | BN_clear_free(rsa->dmp1); | |
424 | BN_clear_free(rsa->dmq1); | |
425 | BN_clear_free(rsa->iqmp); | |
426 | } | |
427 | } | |
428 | return ok; | |
429 | } | |
430 | ||
431 | /* | |
432 | * For RSA key generation it is not known whether the key pair will be used | |
433 | * for key transport or signatures. FIPS 140-2 IG 9.9 states that in this case | |
434 | * either a signature verification OR an encryption operation may be used to | |
435 | * perform the pairwise consistency check. The simpler encrypt/decrypt operation | |
436 | * has been chosen for this case. | |
437 | */ | |
438 | static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg) | |
439 | { | |
440 | int ret = 0; | |
441 | unsigned int ciphertxt_len; | |
442 | unsigned char *ciphertxt = NULL; | |
443 | const unsigned char plaintxt[16] = {0}; | |
444 | unsigned char decoded[256]; | |
445 | unsigned int decoded_len; | |
446 | unsigned int plaintxt_len = (unsigned int)sizeof(plaintxt_len); | |
447 | int padding = RSA_PKCS1_PADDING; | |
448 | OSSL_SELF_TEST *st = NULL; | |
449 | ||
450 | st = OSSL_SELF_TEST_new(cb, cbarg); | |
451 | if (st == NULL) | |
452 | goto err; | |
453 | OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT, | |
454 | OSSL_SELF_TEST_DESC_PCT_RSA_PKCS1); | |
455 | ||
456 | ciphertxt_len = RSA_size(rsa); | |
457 | ciphertxt = OPENSSL_zalloc(ciphertxt_len); | |
458 | if (ciphertxt == NULL) | |
459 | goto err; | |
460 | ||
461 | ciphertxt_len = RSA_public_encrypt(plaintxt_len, plaintxt, ciphertxt, rsa, | |
462 | padding); | |
463 | if (ciphertxt_len <= 0) | |
464 | goto err; | |
465 | if (ciphertxt_len == plaintxt_len | |
466 | && memcmp(decoded, plaintxt, plaintxt_len) == 0) | |
467 | goto err; | |
468 | ||
469 | OSSL_SELF_TEST_oncorrupt_byte(st, ciphertxt); | |
470 | ||
471 | decoded_len = RSA_private_decrypt(ciphertxt_len, ciphertxt, decoded, rsa, | |
472 | padding); | |
473 | if (decoded_len != plaintxt_len | |
474 | || memcmp(decoded, plaintxt, decoded_len) != 0) | |
475 | goto err; | |
476 | ||
477 | ret = 1; | |
478 | err: | |
479 | OSSL_SELF_TEST_onend(st, ret); | |
480 | OSSL_SELF_TEST_free(st); | |
481 | OPENSSL_free(ciphertxt); | |
482 | ||
483 | return ret; | |
0f113f3e | 484 | } |