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 are
61 * 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, BN_GENCB *cb);
75
76 /* NB: this wrapper would normally be placed in rsa_lib.c and the static
77 * implementation would probably be in rsa_eay.c. Nonetheless, is kept here so
78 * that we don't introduce a new linker dependency. Eg. any application that
79 * wasn't previously linking object code related to key-generation won't have to
80 * now just because key-generation is part of RSA_METHOD. */
81 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
82 {
83 #ifdef OPENSSL_FIPS
84 if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
85 && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
86 {
87 RSAerr(RSA_F_RSA_GENERATE_KEY_EX, RSA_R_NON_FIPS_RSA_METHOD);
88 return 0;
89 }
90 #endif
91 if(rsa->meth->rsa_keygen)
92 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
93 #ifdef OPENSSL_FIPS
94 if (FIPS_mode())
95 return FIPS_rsa_generate_key_ex(rsa, bits, e_value, cb);
96 #endif
97 return rsa_builtin_keygen(rsa, bits, e_value, cb);
98 }
99
100 static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
101 {
102 BIGNUM *r0=NULL,*r1=NULL,*r2=NULL,*r3=NULL,*tmp;
103 BIGNUM local_r0,local_d,local_p;
104 BIGNUM *pr0,*d,*p;
105 int bitsp,bitsq,ok= -1,n=0;
106 BN_CTX *ctx=NULL;
107
108 ctx=BN_CTX_new();
109 if (ctx == NULL) goto err;
110 BN_CTX_start(ctx);
111 r0 = BN_CTX_get(ctx);
112 r1 = BN_CTX_get(ctx);
113 r2 = BN_CTX_get(ctx);
114 r3 = BN_CTX_get(ctx);
115 if (r3 == NULL) goto err;
116
117 bitsp=(bits+1)/2;
118 bitsq=bits-bitsp;
119
120 /* We need the RSA components non-NULL */
121 if(!rsa->n && ((rsa->n=BN_new()) == NULL)) goto err;
122 if(!rsa->d && ((rsa->d=BN_new()) == NULL)) goto err;
123 if(!rsa->e && ((rsa->e=BN_new()) == NULL)) goto err;
124 if(!rsa->p && ((rsa->p=BN_new()) == NULL)) goto err;
125 if(!rsa->q && ((rsa->q=BN_new()) == NULL)) goto err;
126 if(!rsa->dmp1 && ((rsa->dmp1=BN_new()) == NULL)) goto err;
127 if(!rsa->dmq1 && ((rsa->dmq1=BN_new()) == NULL)) goto err;
128 if(!rsa->iqmp && ((rsa->iqmp=BN_new()) == NULL)) goto err;
129
130 BN_copy(rsa->e, e_value);
131
132 /* generate p and q */
133 for (;;)
134 {
135 if(!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
136 goto err;
137 if (!BN_sub(r2,rsa->p,BN_value_one())) goto err;
138 if (!BN_gcd(r1,r2,rsa->e,ctx)) goto err;
139 if (BN_is_one(r1)) break;
140 if(!BN_GENCB_call(cb, 2, n++))
141 goto err;
142 }
143 if(!BN_GENCB_call(cb, 3, 0))
144 goto err;
145 for (;;)
146 {
147 /* When generating ridiculously small keys, we can get stuck
148 * continually regenerating the same prime values. Check for
149 * this and bail if it happens 3 times. */
150 unsigned int degenerate = 0;
151 do
152 {
153 if(!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
154 goto err;
155 } while((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
156 if(degenerate == 3)
157 {
158 ok = 0; /* we set our own err */
159 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN,RSA_R_KEY_SIZE_TOO_SMALL);
160 goto err;
161 }
162 if (!BN_sub(r2,rsa->q,BN_value_one())) goto err;
163 if (!BN_gcd(r1,r2,rsa->e,ctx)) goto err;
164 if (BN_is_one(r1))
165 break;
166 if(!BN_GENCB_call(cb, 2, n++))
167 goto err;
168 }
169 if(!BN_GENCB_call(cb, 3, 1))
170 goto err;
171 if (BN_cmp(rsa->p,rsa->q) < 0)
172 {
173 tmp=rsa->p;
174 rsa->p=rsa->q;
175 rsa->q=tmp;
176 }
177
178 /* calculate n */
179 if (!BN_mul(rsa->n,rsa->p,rsa->q,ctx)) goto err;
180
181 /* calculate d */
182 if (!BN_sub(r1,rsa->p,BN_value_one())) goto err; /* p-1 */
183 if (!BN_sub(r2,rsa->q,BN_value_one())) goto err; /* q-1 */
184 if (!BN_mul(r0,r1,r2,ctx)) goto err; /* (p-1)(q-1) */
185 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
186 {
187 pr0 = &local_r0;
188 BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
189 }
190 else
191 pr0 = r0;
192 if (!BN_mod_inverse(rsa->d,rsa->e,pr0,ctx)) goto err; /* d */
193
194 /* set up d for correct BN_FLG_CONSTTIME flag */
195 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
196 {
197 d = &local_d;
198 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
199 }
200 else
201 d = rsa->d;
202
203 /* calculate d mod (p-1) */
204 if (!BN_mod(rsa->dmp1,d,r1,ctx)) goto err;
205
206 /* calculate d mod (q-1) */
207 if (!BN_mod(rsa->dmq1,d,r2,ctx)) goto err;
208
209 /* calculate inverse of q mod p */
210 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
211 {
212 p = &local_p;
213 BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
214 }
215 else
216 p = rsa->p;
217 if (!BN_mod_inverse(rsa->iqmp,rsa->q,p,ctx)) goto err;
218
219 ok=1;
220 err:
221 if (ok == -1)
222 {
223 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN,ERR_LIB_BN);
224 ok=0;
225 }
226 if (ctx != NULL)
227 {
228 BN_CTX_end(ctx);
229 BN_CTX_free(ctx);
230 }
231
232 return ok;
233 }