2 * Copyright 1995-2020 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 * NB: these functions have been "upgraded", the deprecated versions (which
12 * are compatibility wrappers using these functions) are in rsa_depr.c. -
17 * RSA low level APIs are deprecated for public use, but still ok for
20 #include "internal/deprecated.h"
24 #include "internal/cryptlib.h"
25 #include <openssl/bn.h>
26 #include <openssl/self_test.h>
27 #include "rsa_local.h"
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);
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.
40 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
42 if (rsa->meth->rsa_keygen != NULL)
43 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
45 return RSA_generate_multi_prime_key(rsa, bits, RSA_DEFAULT_PRIME_NUM,
49 int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes,
50 BIGNUM *e_value, BN_GENCB *cb)
53 /* multi-prime is only supported with the builtin key generation */
54 if (rsa->meth->rsa_multi_prime_keygen != NULL) {
55 return rsa->meth->rsa_multi_prime_keygen(rsa, bits, primes,
57 } else if (rsa->meth->rsa_keygen != NULL) {
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
65 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
69 #endif /* FIPS_MODULE */
70 return rsa_keygen(NULL, rsa, bits, primes, e_value, cb, 0);
73 static int rsa_keygen(OPENSSL_CTX *libctx, RSA *rsa, int bits, int primes,
74 BIGNUM *e_value, BN_GENCB *cb, int pairwise_test)
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 */
83 BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *tmp, *prime;
84 int n = 0, bitsr[RSA_MAX_PRIME_NUM], bitse = 0;
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;
90 unsigned long error = 0;
92 if (bits < RSA_MIN_MODULUS_BITS) {
93 ok = 0; /* we set our own err */
94 RSAerr(0, RSA_R_KEY_SIZE_TOO_SMALL);
98 if (primes < RSA_DEFAULT_PRIME_NUM || primes > rsa_multip_cap(bits)) {
99 ok = 0; /* we set our own err */
100 RSAerr(0, RSA_R_KEY_PRIME_NUM_INVALID);
108 r0 = BN_CTX_get(ctx);
109 r1 = BN_CTX_get(ctx);
110 r2 = BN_CTX_get(ctx);
114 /* divide bits into 'primes' pieces evenly */
118 for (i = 0; i < primes; i++)
119 bitsr[i] = (i < rmd) ? quo + 1 : quo;
123 /* We need the RSA components non-NULL */
124 if (!rsa->n && ((rsa->n = BN_new()) == NULL))
126 if (!rsa->d && ((rsa->d = BN_secure_new()) == NULL))
128 if (!rsa->e && ((rsa->e = BN_new()) == NULL))
130 if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL))
132 if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL))
134 if (!rsa->dmp1 && ((rsa->dmp1 = BN_secure_new()) == NULL))
136 if (!rsa->dmq1 && ((rsa->dmq1 = BN_secure_new()) == NULL))
138 if (!rsa->iqmp && ((rsa->iqmp = BN_secure_new()) == NULL))
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)
147 if (rsa->prime_infos != NULL) {
148 /* could this happen? */
149 sk_RSA_PRIME_INFO_pop_free(rsa->prime_infos, rsa_multip_info_free);
151 rsa->prime_infos = prime_infos;
153 /* prime_info from 2 to |primes| -1 */
154 for (i = 2; i < primes; i++) {
155 pinfo = rsa_multip_info_new();
158 (void)sk_RSA_PRIME_INFO_push(prime_infos, pinfo);
162 if (BN_copy(rsa->e, e_value) == NULL)
165 /* generate p, q and other primes (if any) */
166 for (i = 0; i < primes; i++) {
175 pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2);
178 BN_set_flags(prime, BN_FLG_CONSTTIME);
182 if (!BN_generate_prime_ex(prime, bitsr[i] + adj, 0, NULL, NULL, cb))
185 * prime should not be equal to p, q, r_3...
186 * (those primes prior to this one)
191 for (j = 0; j < i; j++) {
199 prev_prime = sk_RSA_PRIME_INFO_value(prime_infos,
202 if (!BN_cmp(prime, prev_prime)) {
207 if (!BN_sub(r2, prime, BN_value_one()))
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 */
215 error = ERR_peek_last_error();
216 if (ERR_GET_LIB(error) == ERR_LIB_BN
217 && ERR_GET_REASON(error) == BN_R_NO_INVERSE) {
223 if (!BN_GENCB_call(cb, 2, n++))
229 /* calculate n immediately to see if it's sufficient */
231 /* we get at least 2 primes */
232 if (!BN_mul(r1, rsa->p, rsa->q, ctx))
235 /* modulus n = p * q * r_3 * r_4 ... */
236 if (!BN_mul(r1, rsa->n, prime, ctx))
239 /* i == 0, do nothing */
240 if (!BN_GENCB_call(cb, 3, i))
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.
249 * NOTE: This actually can't happen in two-prime case, because of
250 * the way factors are generated.
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.
258 if (!BN_rshift(r2, r1, bitse - 4))
260 bitst = BN_get_word(r2);
262 if (bitst < 0x9 || bitst > 0xF) {
264 * For keys with more than 4 primes, we attempt longer factor to
265 * meet length requirement.
267 * Otherwise, we just re-generate the prime with the same length.
269 * This strategy has the following goals:
271 * 1. 1024-bit factors are efficient when using 3072 and 4096-bit key
272 * 2. stay the same logic with normal 2-prime key
275 if (!BN_GENCB_call(cb, 2, n++))
282 } else if (retries == 4) {
284 * re-generate all primes from scratch, mainly used
285 * in 4 prime case to avoid long loop. Max retry times
295 /* save product of primes for further use, for multi-prime only */
296 if (i > 1 && BN_copy(pinfo->pp, rsa->n) == NULL)
298 if (BN_copy(rsa->n, r1) == NULL)
300 if (!BN_GENCB_call(cb, 3, i))
304 if (BN_cmp(rsa->p, rsa->q) < 0) {
313 if (!BN_sub(r1, rsa->p, BN_value_one()))
316 if (!BN_sub(r2, rsa->q, BN_value_one()))
319 if (!BN_mul(r0, r1, r2, ctx))
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()))
327 if (!BN_mul(r0, r0, pinfo->d, ctx))
332 BIGNUM *pr0 = BN_new();
337 BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
338 if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) {
342 /* We MUST free pr0 before any further use of r0 */
347 BIGNUM *d = BN_new();
352 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
354 /* calculate d mod (p-1) and d mod (q - 1) */
355 if (!BN_mod(rsa->dmp1, d, r1, ctx)
356 || !BN_mod(rsa->dmq1, d, r2, ctx)) {
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)) {
371 /* We MUST free d before any further use of rsa->d */
376 BIGNUM *p = BN_new();
380 BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
382 /* calculate inverse of q mod p */
383 if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) {
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)) {
398 /* We MUST free p before any further use of rsa->p */
405 RSAerr(0, ERR_LIB_BN);
410 #endif /* FIPS_MODULE */
412 if (pairwise_test && ok > 0) {
413 OSSL_CALLBACK *stcb = NULL;
414 void *stcbarg = NULL;
416 OSSL_SELF_TEST_get_callback(libctx, &stcb, &stcbarg);
417 ok = rsa_keygen_pairwise_test(rsa, stcb, stcbarg);
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);
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.
438 static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg)
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;
450 st = OSSL_SELF_TEST_new(cb, cbarg);
453 OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
454 OSSL_SELF_TEST_DESC_PCT_RSA_PKCS1);
456 ciphertxt_len = RSA_size(rsa);
457 ciphertxt = OPENSSL_zalloc(ciphertxt_len);
458 if (ciphertxt == NULL)
461 ciphertxt_len = RSA_public_encrypt(plaintxt_len, plaintxt, ciphertxt, rsa,
463 if (ciphertxt_len <= 0)
465 if (ciphertxt_len == plaintxt_len
466 && memcmp(decoded, plaintxt, plaintxt_len) == 0)
469 OSSL_SELF_TEST_oncorrupt_byte(st, ciphertxt);
471 decoded_len = RSA_private_decrypt(ciphertxt_len, ciphertxt, decoded, rsa,
473 if (decoded_len != plaintxt_len
474 || memcmp(decoded, plaintxt, decoded_len) != 0)
479 OSSL_SELF_TEST_onend(st, ret);
480 OSSL_SELF_TEST_free(st);
481 OPENSSL_free(ciphertxt);