Line data Source code
1 : /* crypto/rsa/rsa_gen.c */
2 : /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 : * All rights reserved.
4 : *
5 : * This package is an SSL implementation written
6 : * by Eric Young (eay@cryptsoft.com).
7 : * The implementation was written so as to conform with Netscapes SSL.
8 : *
9 : * This library is free for commercial and non-commercial use as long as
10 : * the following conditions are aheared to. The following conditions
11 : * apply to all code found in this distribution, be it the RC4, RSA,
12 : * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 : * included with this distribution is covered by the same copyright terms
14 : * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 : *
16 : * Copyright remains Eric Young's, and as such any Copyright notices in
17 : * the code are not to be removed.
18 : * If this package is used in a product, Eric Young should be given attribution
19 : * as the author of the parts of the library used.
20 : * This can be in the form of a textual message at program startup or
21 : * in documentation (online or textual) provided with the package.
22 : *
23 : * Redistribution and use in source and binary forms, with or without
24 : * modification, are permitted provided that the following conditions
25 : * are met:
26 : * 1. Redistributions of source code must retain the copyright
27 : * notice, this list of conditions and the following disclaimer.
28 : * 2. Redistributions in binary form must reproduce the above copyright
29 : * notice, this list of conditions and the following disclaimer in the
30 : * documentation and/or other materials provided with the distribution.
31 : * 3. All advertising materials mentioning features or use of this software
32 : * must display the following acknowledgement:
33 : * "This product includes cryptographic software written by
34 : * Eric Young (eay@cryptsoft.com)"
35 : * The word 'cryptographic' can be left out if the rouines from the library
36 : * being used are not cryptographic related :-).
37 : * 4. If you include any Windows specific code (or a derivative thereof) from
38 : * the apps directory (application code) you must include an acknowledgement:
39 : * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 : *
41 : * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 : * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 : * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 : * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 : * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 : * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 : * SUCH DAMAGE.
52 : *
53 : * The licence and distribution terms for any publically available version or
54 : * derivative of this code cannot be changed. i.e. this code cannot simply be
55 : * copied and put under another distribution licence
56 : * [including the GNU Public Licence.]
57 : */
58 :
59 : /*
60 : * NB: these functions have been "upgraded", the deprecated versions (which
61 : * are compatibility wrappers using these functions) are in rsa_depr.c. -
62 : * Geoff
63 : */
64 :
65 : #include <stdio.h>
66 : #include <time.h>
67 : #include "cryptlib.h"
68 : #include <openssl/bn.h>
69 : #include <openssl/rsa.h>
70 : #ifdef OPENSSL_FIPS
71 : # include <openssl/fips.h>
72 : #endif
73 :
74 : static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
75 : BN_GENCB *cb);
76 :
77 : /*
78 : * NB: this wrapper would normally be placed in rsa_lib.c and the static
79 : * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
80 : * so that we don't introduce a new linker dependency. Eg. any application
81 : * that wasn't previously linking object code related to key-generation won't
82 : * have to now just because key-generation is part of RSA_METHOD.
83 : */
84 0 : int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
85 : {
86 : #ifdef OPENSSL_FIPS
87 : if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
88 : && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) {
89 : RSAerr(RSA_F_RSA_GENERATE_KEY_EX, RSA_R_NON_FIPS_RSA_METHOD);
90 : return 0;
91 : }
92 : #endif
93 0 : if (rsa->meth->rsa_keygen)
94 0 : return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
95 : #ifdef OPENSSL_FIPS
96 : if (FIPS_mode())
97 : return FIPS_rsa_generate_key_ex(rsa, bits, e_value, cb);
98 : #endif
99 0 : return rsa_builtin_keygen(rsa, bits, e_value, cb);
100 : }
101 :
102 0 : static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
103 : BN_GENCB *cb)
104 : {
105 : BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
106 : BIGNUM local_r0, local_d, local_p;
107 : BIGNUM *pr0, *d, *p;
108 : int bitsp, bitsq, ok = -1, n = 0;
109 : BN_CTX *ctx = NULL;
110 :
111 0 : ctx = BN_CTX_new();
112 0 : if (ctx == NULL)
113 : goto err;
114 0 : BN_CTX_start(ctx);
115 0 : r0 = BN_CTX_get(ctx);
116 0 : r1 = BN_CTX_get(ctx);
117 0 : r2 = BN_CTX_get(ctx);
118 0 : r3 = BN_CTX_get(ctx);
119 0 : if (r3 == NULL)
120 : goto err;
121 :
122 0 : bitsp = (bits + 1) / 2;
123 0 : bitsq = bits - bitsp;
124 :
125 : /* We need the RSA components non-NULL */
126 0 : if (!rsa->n && ((rsa->n = BN_new()) == NULL))
127 : goto err;
128 0 : if (!rsa->d && ((rsa->d = BN_new()) == NULL))
129 : goto err;
130 0 : if (!rsa->e && ((rsa->e = BN_new()) == NULL))
131 : goto err;
132 0 : if (!rsa->p && ((rsa->p = BN_new()) == NULL))
133 : goto err;
134 0 : if (!rsa->q && ((rsa->q = BN_new()) == NULL))
135 : goto err;
136 0 : if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL))
137 : goto err;
138 0 : if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL))
139 : goto err;
140 0 : if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL))
141 : goto err;
142 :
143 0 : BN_copy(rsa->e, e_value);
144 :
145 : /* generate p and q */
146 : for (;;) {
147 0 : if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
148 : goto err;
149 0 : if (!BN_sub(r2, rsa->p, BN_value_one()))
150 : goto err;
151 0 : if (!BN_gcd(r1, r2, rsa->e, ctx))
152 : goto err;
153 0 : if (BN_is_one(r1))
154 : break;
155 0 : if (!BN_GENCB_call(cb, 2, n++))
156 : goto err;
157 : }
158 0 : if (!BN_GENCB_call(cb, 3, 0))
159 : goto err;
160 : for (;;) {
161 : /*
162 : * When generating ridiculously small keys, we can get stuck
163 : * continually regenerating the same prime values. Check for this and
164 : * bail if it happens 3 times.
165 : */
166 : unsigned int degenerate = 0;
167 : do {
168 0 : if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
169 : goto err;
170 0 : } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
171 0 : if (degenerate == 3) {
172 : ok = 0; /* we set our own err */
173 0 : RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL);
174 0 : goto err;
175 : }
176 0 : if (!BN_sub(r2, rsa->q, BN_value_one()))
177 : goto err;
178 0 : if (!BN_gcd(r1, r2, rsa->e, ctx))
179 : goto err;
180 0 : if (BN_is_one(r1))
181 : break;
182 0 : if (!BN_GENCB_call(cb, 2, n++))
183 : goto err;
184 : }
185 0 : if (!BN_GENCB_call(cb, 3, 1))
186 : goto err;
187 0 : if (BN_cmp(rsa->p, rsa->q) < 0) {
188 0 : tmp = rsa->p;
189 0 : rsa->p = rsa->q;
190 0 : rsa->q = tmp;
191 : }
192 :
193 : /* calculate n */
194 0 : if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
195 : goto err;
196 :
197 : /* calculate d */
198 0 : if (!BN_sub(r1, rsa->p, BN_value_one()))
199 : goto err; /* p-1 */
200 0 : if (!BN_sub(r2, rsa->q, BN_value_one()))
201 : goto err; /* q-1 */
202 0 : if (!BN_mul(r0, r1, r2, ctx))
203 : goto err; /* (p-1)(q-1) */
204 0 : if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
205 : pr0 = &local_r0;
206 0 : BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
207 : } else
208 : pr0 = r0;
209 0 : if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx))
210 : goto err; /* d */
211 :
212 : /* set up d for correct BN_FLG_CONSTTIME flag */
213 0 : if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
214 : d = &local_d;
215 0 : BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
216 : } else
217 0 : d = rsa->d;
218 :
219 : /* calculate d mod (p-1) */
220 0 : if (!BN_mod(rsa->dmp1, d, r1, ctx))
221 : goto err;
222 :
223 : /* calculate d mod (q-1) */
224 0 : if (!BN_mod(rsa->dmq1, d, r2, ctx))
225 : goto err;
226 :
227 : /* calculate inverse of q mod p */
228 0 : if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
229 : p = &local_p;
230 0 : BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
231 : } else
232 0 : p = rsa->p;
233 0 : if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx))
234 : goto err;
235 :
236 : ok = 1;
237 : err:
238 0 : if (ok == -1) {
239 0 : RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN);
240 : ok = 0;
241 : }
242 0 : if (ctx != NULL) {
243 0 : BN_CTX_end(ctx);
244 0 : BN_CTX_free(ctx);
245 : }
246 :
247 0 : return ok;
248 : }
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