rsa_gen.c revision 296341
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 74static 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 */ 84int 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 if (rsa->meth->rsa_keygen) 94 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 return rsa_builtin_keygen(rsa, bits, e_value, cb); 100} 101 102static 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 ctx = BN_CTX_new(); 112 if (ctx == NULL) 113 goto err; 114 BN_CTX_start(ctx); 115 r0 = BN_CTX_get(ctx); 116 r1 = BN_CTX_get(ctx); 117 r2 = BN_CTX_get(ctx); 118 r3 = BN_CTX_get(ctx); 119 if (r3 == NULL) 120 goto err; 121 122 bitsp = (bits + 1) / 2; 123 bitsq = bits - bitsp; 124 125 /* We need the RSA components non-NULL */ 126 if (!rsa->n && ((rsa->n = BN_new()) == NULL)) 127 goto err; 128 if (!rsa->d && ((rsa->d = BN_new()) == NULL)) 129 goto err; 130 if (!rsa->e && ((rsa->e = BN_new()) == NULL)) 131 goto err; 132 if (!rsa->p && ((rsa->p = BN_new()) == NULL)) 133 goto err; 134 if (!rsa->q && ((rsa->q = BN_new()) == NULL)) 135 goto err; 136 if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL)) 137 goto err; 138 if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL)) 139 goto err; 140 if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL)) 141 goto err; 142 143 BN_copy(rsa->e, e_value); 144 145 /* generate p and q */ 146 for (;;) { 147 if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb)) 148 goto err; 149 if (!BN_sub(r2, rsa->p, BN_value_one())) 150 goto err; 151 if (!BN_gcd(r1, r2, rsa->e, ctx)) 152 goto err; 153 if (BN_is_one(r1)) 154 break; 155 if (!BN_GENCB_call(cb, 2, n++)) 156 goto err; 157 } 158 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 if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb)) 169 goto err; 170 } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3)); 171 if (degenerate == 3) { 172 ok = 0; /* we set our own err */ 173 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL); 174 goto err; 175 } 176 if (!BN_sub(r2, rsa->q, BN_value_one())) 177 goto err; 178 if (!BN_gcd(r1, r2, rsa->e, ctx)) 179 goto err; 180 if (BN_is_one(r1)) 181 break; 182 if (!BN_GENCB_call(cb, 2, n++)) 183 goto err; 184 } 185 if (!BN_GENCB_call(cb, 3, 1)) 186 goto err; 187 if (BN_cmp(rsa->p, rsa->q) < 0) { 188 tmp = rsa->p; 189 rsa->p = rsa->q; 190 rsa->q = tmp; 191 } 192 193 /* calculate n */ 194 if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx)) 195 goto err; 196 197 /* calculate d */ 198 if (!BN_sub(r1, rsa->p, BN_value_one())) 199 goto err; /* p-1 */ 200 if (!BN_sub(r2, rsa->q, BN_value_one())) 201 goto err; /* q-1 */ 202 if (!BN_mul(r0, r1, r2, ctx)) 203 goto err; /* (p-1)(q-1) */ 204 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 205 pr0 = &local_r0; 206 BN_with_flags(pr0, r0, BN_FLG_CONSTTIME); 207 } else 208 pr0 = r0; 209 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 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 214 d = &local_d; 215 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); 216 } else 217 d = rsa->d; 218 219 /* calculate d mod (p-1) */ 220 if (!BN_mod(rsa->dmp1, d, r1, ctx)) 221 goto err; 222 223 /* calculate d mod (q-1) */ 224 if (!BN_mod(rsa->dmq1, d, r2, ctx)) 225 goto err; 226 227 /* calculate inverse of q mod p */ 228 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 229 p = &local_p; 230 BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); 231 } else 232 p = rsa->p; 233 if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) 234 goto err; 235 236 ok = 1; 237 err: 238 if (ok == -1) { 239 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN); 240 ok = 0; 241 } 242 if (ctx != NULL) { 243 BN_CTX_end(ctx); 244 BN_CTX_free(ctx); 245 } 246 247 return ok; 248} 249