2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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. -
18 #include "internal/cryptlib.h"
19 #include <openssl/bn.h>
22 static int rsa_builtin_keygen(RSA
*rsa
, int bits
, int primes
, BIGNUM
*e_value
,
26 * NB: this wrapper would normally be placed in rsa_lib.c and the static
27 * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
28 * so that we don't introduce a new linker dependency. Eg. any application
29 * that wasn't previously linking object code related to key-generation won't
30 * have to now just because key-generation is part of RSA_METHOD.
32 int RSA_generate_key_ex(RSA
*rsa
, int bits
, BIGNUM
*e_value
, BN_GENCB
*cb
)
34 if (rsa
->meth
->rsa_keygen
!= NULL
)
35 return rsa
->meth
->rsa_keygen(rsa
, bits
, e_value
, cb
);
37 return RSA_generate_multi_prime_key(rsa
, bits
, RSA_DEFAULT_PRIME_NUM
,
41 int RSA_generate_multi_prime_key(RSA
*rsa
, int bits
, int primes
,
42 BIGNUM
*e_value
, BN_GENCB
*cb
)
44 /* multi-prime is only supported with the builtin key generation */
45 if (rsa
->meth
->rsa_multi_prime_keygen
!= NULL
) {
46 return rsa
->meth
->rsa_multi_prime_keygen(rsa
, bits
, primes
,
48 } else if (rsa
->meth
->rsa_keygen
!= NULL
) {
50 * However, if rsa->meth implements only rsa_keygen, then we
51 * have to honour it in 2-prime case and assume that it wouldn't
52 * know what to do with multi-prime key generated by builtin
56 return rsa
->meth
->rsa_keygen(rsa
, bits
, e_value
, cb
);
61 return rsa_builtin_keygen(rsa
, bits
, primes
, e_value
, cb
);
64 static int rsa_builtin_keygen(RSA
*rsa
, int bits
, int primes
, BIGNUM
*e_value
,
67 BIGNUM
*r0
= NULL
, *r1
= NULL
, *r2
= NULL
, *tmp
, *prime
;
68 int ok
= -1, n
= 0, bitsr
[RSA_MAX_PRIME_NUM
], bitse
= 0;
69 int i
= 0, quo
= 0, rmd
= 0, adj
= 0, retries
= 0;
70 RSA_PRIME_INFO
*pinfo
= NULL
;
71 STACK_OF(RSA_PRIME_INFO
) *prime_infos
= NULL
;
74 unsigned long error
= 0;
76 if (bits
< RSA_MIN_MODULUS_BITS
) {
77 ok
= 0; /* we set our own err */
78 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN
, RSA_R_KEY_SIZE_TOO_SMALL
);
82 if (primes
< RSA_DEFAULT_PRIME_NUM
|| primes
> rsa_multip_cap(bits
)) {
83 ok
= 0; /* we set our own err */
84 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN
, RSA_R_KEY_PRIME_NUM_INVALID
);
98 /* divide bits into 'primes' pieces evenly */
102 for (i
= 0; i
< primes
; i
++)
103 bitsr
[i
] = (i
< rmd
) ? quo
+ 1 : quo
;
105 /* We need the RSA components non-NULL */
106 if (!rsa
->n
&& ((rsa
->n
= BN_new()) == NULL
))
108 if (!rsa
->d
&& ((rsa
->d
= BN_secure_new()) == NULL
))
110 if (!rsa
->e
&& ((rsa
->e
= BN_new()) == NULL
))
112 if (!rsa
->p
&& ((rsa
->p
= BN_secure_new()) == NULL
))
114 if (!rsa
->q
&& ((rsa
->q
= BN_secure_new()) == NULL
))
116 if (!rsa
->dmp1
&& ((rsa
->dmp1
= BN_secure_new()) == NULL
))
118 if (!rsa
->dmq1
&& ((rsa
->dmq1
= BN_secure_new()) == NULL
))
120 if (!rsa
->iqmp
&& ((rsa
->iqmp
= BN_secure_new()) == NULL
))
123 /* initialize multi-prime components */
124 if (primes
> RSA_DEFAULT_PRIME_NUM
) {
125 rsa
->version
= RSA_ASN1_VERSION_MULTI
;
126 prime_infos
= sk_RSA_PRIME_INFO_new_reserve(NULL
, primes
- 2);
127 if (prime_infos
== NULL
)
129 if (rsa
->prime_infos
!= NULL
) {
130 /* could this happen? */
131 sk_RSA_PRIME_INFO_pop_free(rsa
->prime_infos
, rsa_multip_info_free
);
133 rsa
->prime_infos
= prime_infos
;
135 /* prime_info from 2 to |primes| -1 */
136 for (i
= 2; i
< primes
; i
++) {
137 pinfo
= rsa_multip_info_new();
140 (void)sk_RSA_PRIME_INFO_push(prime_infos
, pinfo
);
144 if (BN_copy(rsa
->e
, e_value
) == NULL
)
147 /* generate p, q and other primes (if any) */
148 for (i
= 0; i
< primes
; i
++) {
157 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
163 if (!BN_generate_prime_ex(prime
, bitsr
[i
] + adj
, 0, NULL
, NULL
, cb
))
166 * prime should not be equal to p, q, r_3...
167 * (those primes prior to this one)
172 for (j
= 0; j
< i
; j
++) {
180 prev_prime
= sk_RSA_PRIME_INFO_value(prime_infos
,
183 if (!BN_cmp(prime
, prev_prime
)) {
188 if (!BN_sub(r2
, prime
, BN_value_one()))
191 BN_set_flags(r2
, BN_FLG_CONSTTIME
);
192 if (BN_mod_inverse(r1
, r2
, rsa
->e
, ctx
) != NULL
) {
193 /* GCD == 1 since inverse exists */
196 error
= ERR_peek_last_error();
197 if (ERR_GET_LIB(error
) == ERR_LIB_BN
198 && ERR_GET_REASON(error
) == BN_R_NO_INVERSE
) {
204 if (!BN_GENCB_call(cb
, 2, n
++))
210 /* calculate n immediately to see if it's sufficient */
212 /* we get at least 2 primes */
213 if (!BN_mul(r1
, rsa
->p
, rsa
->q
, ctx
))
216 /* modulus n = p * q * r_3 * r_4 ... */
217 if (!BN_mul(r1
, rsa
->n
, prime
, ctx
))
220 /* i == 0, do nothing */
221 if (!BN_GENCB_call(cb
, 3, i
))
226 * if |r1|, product of factors so far, is not as long as expected
227 * (by checking the first 4 bits are less than 0x9 or greater than
228 * 0xF). If so, re-generate the last prime.
230 * NOTE: This actually can't happen in two-prime case, because of
231 * the way factors are generated.
233 * Besides, another consideration is, for multi-prime case, even the
234 * length modulus is as long as expected, the modulus could start at
235 * 0x8, which could be utilized to distinguish a multi-prime private
236 * key by using the modulus in a certificate. This is also covered
237 * by checking the length should not be less than 0x9.
239 if (!BN_rshift(r2
, r1
, bitse
- 4))
241 bitst
= BN_get_word(r2
);
243 if (bitst
< 0x9 || bitst
> 0xF) {
245 * For keys with more than 4 primes, we attempt longer factor to
246 * meet length requirement.
248 * Otherwise, we just re-generate the prime with the same length.
250 * This strategy has the following goals:
252 * 1. 1024-bit factors are effcient when using 3072 and 4096-bit key
253 * 2. stay the same logic with normal 2-prime key
256 if (!BN_GENCB_call(cb
, 2, n
++))
263 } else if (retries
== 4) {
265 * re-generate all primes from scratch, mainly used
266 * in 4 prime case to avoid long loop. Max retry times
276 /* save product of primes for further use, for multi-prime only */
277 if (i
> 1 && BN_copy(pinfo
->pp
, rsa
->n
) == NULL
)
279 if (BN_copy(rsa
->n
, r1
) == NULL
)
281 if (!BN_GENCB_call(cb
, 3, i
))
285 if (BN_cmp(rsa
->p
, rsa
->q
) < 0) {
294 if (!BN_sub(r1
, rsa
->p
, BN_value_one()))
297 if (!BN_sub(r2
, rsa
->q
, BN_value_one()))
300 if (!BN_mul(r0
, r1
, r2
, ctx
))
303 for (i
= 2; i
< primes
; i
++) {
304 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
305 /* save r_i - 1 to pinfo->d temporarily */
306 if (!BN_sub(pinfo
->d
, pinfo
->r
, BN_value_one()))
308 if (!BN_mul(r0
, r0
, pinfo
->d
, ctx
))
313 BIGNUM
*pr0
= BN_new();
318 BN_with_flags(pr0
, r0
, BN_FLG_CONSTTIME
);
319 if (!BN_mod_inverse(rsa
->d
, rsa
->e
, pr0
, ctx
)) {
323 /* We MUST free pr0 before any further use of r0 */
328 BIGNUM
*d
= BN_new();
333 BN_with_flags(d
, rsa
->d
, BN_FLG_CONSTTIME
);
335 /* calculate d mod (p-1) and d mod (q - 1) */
336 if (!BN_mod(rsa
->dmp1
, d
, r1
, ctx
)
337 || !BN_mod(rsa
->dmq1
, d
, r2
, ctx
)) {
342 /* calculate CRT exponents */
343 for (i
= 2; i
< primes
; i
++) {
344 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
345 /* pinfo->d == r_i - 1 */
346 if (!BN_mod(pinfo
->d
, d
, pinfo
->d
, ctx
)) {
352 /* We MUST free d before any further use of rsa->d */
357 BIGNUM
*p
= BN_new();
361 BN_with_flags(p
, rsa
->p
, BN_FLG_CONSTTIME
);
363 /* calculate inverse of q mod p */
364 if (!BN_mod_inverse(rsa
->iqmp
, rsa
->q
, p
, ctx
)) {
369 /* calculate CRT coefficient for other primes */
370 for (i
= 2; i
< primes
; i
++) {
371 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
372 BN_with_flags(p
, pinfo
->r
, BN_FLG_CONSTTIME
);
373 if (!BN_mod_inverse(pinfo
->t
, pinfo
->pp
, p
, ctx
)) {
379 /* We MUST free p before any further use of rsa->p */
386 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN
, ERR_LIB_BN
);