rsa_gen.c revision 331638
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> 72extern int FIPS_rsa_x931_generate_key_ex(RSA *rsa, int bits, BIGNUM *e, 73 BN_GENCB *cb); 74#endif 75 76static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, 77 BN_GENCB *cb); 78 79/* 80 * NB: this wrapper would normally be placed in rsa_lib.c and the static 81 * implementation would probably be in rsa_eay.c. Nonetheless, is kept here 82 * so that we don't introduce a new linker dependency. Eg. any application 83 * that wasn't previously linking object code related to key-generation won't 84 * have to now just because key-generation is part of RSA_METHOD. 85 */ 86int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) 87{ 88#ifdef OPENSSL_FIPS 89 if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD) 90 && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) { 91 RSAerr(RSA_F_RSA_GENERATE_KEY_EX, RSA_R_NON_FIPS_RSA_METHOD); 92 return 0; 93 } 94#endif 95 if (rsa->meth->rsa_keygen) 96 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb); 97#ifdef OPENSSL_FIPS 98 if (FIPS_mode()) 99 return FIPS_rsa_x931_generate_key_ex(rsa, bits, e_value, cb); 100#endif 101 return rsa_builtin_keygen(rsa, bits, e_value, cb); 102} 103 104static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, 105 BN_GENCB *cb) 106{ 107 BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp; 108 BIGNUM local_r0, local_d, local_p; 109 BIGNUM *pr0, *d, *p; 110 int bitsp, bitsq, ok = -1, n = 0; 111 BN_CTX *ctx = NULL; 112 unsigned long error = 0; 113 114 /* 115 * When generating ridiculously small keys, we can get stuck 116 * continually regenerating the same prime values. 117 */ 118 if (bits < 16) { 119 ok = 0; /* we set our own err */ 120 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL); 121 goto err; 122 } 123 124 ctx = BN_CTX_new(); 125 if (ctx == NULL) 126 goto err; 127 BN_CTX_start(ctx); 128 r0 = BN_CTX_get(ctx); 129 r1 = BN_CTX_get(ctx); 130 r2 = BN_CTX_get(ctx); 131 r3 = BN_CTX_get(ctx); 132 if (r3 == NULL) 133 goto err; 134 135 bitsp = (bits + 1) / 2; 136 bitsq = bits - bitsp; 137 138 /* We need the RSA components non-NULL */ 139 if (!rsa->n && ((rsa->n = BN_new()) == NULL)) 140 goto err; 141 if (!rsa->d && ((rsa->d = BN_new()) == NULL)) 142 goto err; 143 if (!rsa->e && ((rsa->e = BN_new()) == NULL)) 144 goto err; 145 if (!rsa->p && ((rsa->p = BN_new()) == NULL)) 146 goto err; 147 if (!rsa->q && ((rsa->q = BN_new()) == NULL)) 148 goto err; 149 if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL)) 150 goto err; 151 if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL)) 152 goto err; 153 if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL)) 154 goto err; 155 156 if (BN_copy(rsa->e, e_value) == NULL) 157 goto err; 158 159 BN_set_flags(r2, BN_FLG_CONSTTIME); 160 /* generate p and q */ 161 for (;;) { 162 if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb)) 163 goto err; 164 if (!BN_sub(r2, rsa->p, BN_value_one())) 165 goto err; 166 ERR_set_mark(); 167 if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) { 168 /* GCD == 1 since inverse exists */ 169 break; 170 } 171 error = ERR_peek_last_error(); 172 if (ERR_GET_LIB(error) == ERR_LIB_BN 173 && ERR_GET_REASON(error) == BN_R_NO_INVERSE) { 174 /* GCD != 1 */ 175 ERR_pop_to_mark(); 176 } else { 177 goto err; 178 } 179 if (!BN_GENCB_call(cb, 2, n++)) 180 goto err; 181 } 182 if (!BN_GENCB_call(cb, 3, 0)) 183 goto err; 184 for (;;) { 185 do { 186 if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb)) 187 goto err; 188 } while (BN_cmp(rsa->p, rsa->q) == 0); 189 if (!BN_sub(r2, rsa->q, BN_value_one())) 190 goto err; 191 ERR_set_mark(); 192 if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) { 193 /* GCD == 1 since inverse exists */ 194 break; 195 } 196 error = ERR_peek_last_error(); 197 if (ERR_GET_LIB(error) == ERR_LIB_BN 198 && ERR_GET_REASON(error) == BN_R_NO_INVERSE) { 199 /* GCD != 1 */ 200 ERR_pop_to_mark(); 201 } else { 202 goto err; 203 } 204 if (!BN_GENCB_call(cb, 2, n++)) 205 goto err; 206 } 207 if (!BN_GENCB_call(cb, 3, 1)) 208 goto err; 209 if (BN_cmp(rsa->p, rsa->q) < 0) { 210 tmp = rsa->p; 211 rsa->p = rsa->q; 212 rsa->q = tmp; 213 } 214 215 /* calculate n */ 216 if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx)) 217 goto err; 218 219 /* calculate d */ 220 if (!BN_sub(r1, rsa->p, BN_value_one())) 221 goto err; /* p-1 */ 222 if (!BN_sub(r2, rsa->q, BN_value_one())) 223 goto err; /* q-1 */ 224 if (!BN_mul(r0, r1, r2, ctx)) 225 goto err; /* (p-1)(q-1) */ 226 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 227 pr0 = &local_r0; 228 BN_with_flags(pr0, r0, BN_FLG_CONSTTIME); 229 } else 230 pr0 = r0; 231 if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) 232 goto err; /* d */ 233 234 /* set up d for correct BN_FLG_CONSTTIME flag */ 235 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 236 d = &local_d; 237 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); 238 } else 239 d = rsa->d; 240 241 /* calculate d mod (p-1) */ 242 if (!BN_mod(rsa->dmp1, d, r1, ctx)) 243 goto err; 244 245 /* calculate d mod (q-1) */ 246 if (!BN_mod(rsa->dmq1, d, r2, ctx)) 247 goto err; 248 249 /* calculate inverse of q mod p */ 250 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 251 p = &local_p; 252 BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); 253 } else 254 p = rsa->p; 255 if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) 256 goto err; 257 258 ok = 1; 259 err: 260 if (ok == -1) { 261 RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN); 262 ok = 0; 263 } 264 if (ctx != NULL) { 265 BN_CTX_end(ctx); 266 BN_CTX_free(ctx); 267 } 268 269 return ok; 270} 271