1/* crypto/dsa/dsa_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#undef GENUINE_DSA 60 61#ifdef GENUINE_DSA 62/* 63 * Parameter generation follows the original release of FIPS PUB 186, 64 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) 65 */ 66# define HASH EVP_sha() 67#else 68/* 69 * Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186, 70 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB 71 * 180-1) 72 */ 73# define HASH EVP_sha1() 74#endif 75 76#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ 77 78#ifndef OPENSSL_NO_SHA 79 80# include <stdio.h> 81# include <time.h> 82# include <string.h> 83# include <openssl/evp.h> 84# include <openssl/bn.h> 85# include <openssl/dsa.h> 86# include <openssl/rand.h> 87# include <openssl/sha.h> 88# include <openssl/err.h> 89 90# ifdef OPENSSL_FIPS 91 92static int dsa_builtin_paramgen(DSA *ret, int bits, 93 unsigned char *seed_in, int seed_len, 94 int *counter_ret, unsigned long *h_ret, 95 BN_GENCB *cb); 96 97int DSA_generate_parameters_ex(DSA *ret, int bits, 98 unsigned char *seed_in, int seed_len, 99 int *counter_ret, unsigned long *h_ret, 100 BN_GENCB *cb) 101{ 102 if (ret->meth->dsa_paramgen) 103 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, 104 counter_ret, h_ret, cb); 105 return dsa_builtin_paramgen(ret, bits, seed_in, seed_len, 106 counter_ret, h_ret, cb); 107} 108 109static int dsa_builtin_paramgen(DSA *ret, int bits, 110 unsigned char *seed_in, int seed_len, 111 int *counter_ret, unsigned long *h_ret, 112 BN_GENCB *cb) 113{ 114 int ok = 0; 115 unsigned char seed[SHA_DIGEST_LENGTH]; 116 unsigned char md[SHA_DIGEST_LENGTH]; 117 unsigned char buf[SHA_DIGEST_LENGTH], buf2[SHA_DIGEST_LENGTH]; 118 BIGNUM *r0, *W, *X, *c, *test; 119 BIGNUM *g = NULL, *q = NULL, *p = NULL; 120 BN_MONT_CTX *mont = NULL; 121 int k, n = 0, i, b, m = 0; 122 int counter = 0; 123 int r = 0; 124 BN_CTX *ctx = NULL; 125 unsigned int h = 2; 126 127 if (FIPS_selftest_failed()) { 128 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN, FIPS_R_FIPS_SELFTEST_FAILED); 129 goto err; 130 } 131 132 if (FIPS_mode() && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS)) { 133 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL); 134 goto err; 135 } 136 137 if (bits < 512) 138 bits = 512; 139 bits = (bits + 63) / 64 * 64; 140 141 /* 142 * NB: seed_len == 0 is special case: copy generated seed to seed_in if 143 * it is not NULL. 144 */ 145 if (seed_len && (seed_len < 20)) 146 seed_in = NULL; /* seed buffer too small -- ignore */ 147 if (seed_len > 20) 148 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger 149 * SEED, but our internal buffers are 150 * restricted to 160 bits */ 151 if ((seed_in != NULL) && (seed_len == 20)) { 152 memcpy(seed, seed_in, seed_len); 153 /* set seed_in to NULL to avoid it being copied back */ 154 seed_in = NULL; 155 } 156 157 if ((ctx = BN_CTX_new()) == NULL) 158 goto err; 159 160 if ((mont = BN_MONT_CTX_new()) == NULL) 161 goto err; 162 163 BN_CTX_start(ctx); 164 r0 = BN_CTX_get(ctx); 165 g = BN_CTX_get(ctx); 166 W = BN_CTX_get(ctx); 167 q = BN_CTX_get(ctx); 168 X = BN_CTX_get(ctx); 169 c = BN_CTX_get(ctx); 170 p = BN_CTX_get(ctx); 171 test = BN_CTX_get(ctx); 172 173 if (!BN_lshift(test, BN_value_one(), bits - 1)) 174 goto err; 175 176 for (;;) { 177 for (;;) { /* find q */ 178 int seed_is_random; 179 180 /* step 1 */ 181 if (!BN_GENCB_call(cb, 0, m++)) 182 goto err; 183 184 if (!seed_len) { 185 RAND_pseudo_bytes(seed, SHA_DIGEST_LENGTH); 186 seed_is_random = 1; 187 } else { 188 seed_is_random = 0; 189 seed_len = 0; /* use random seed if 'seed_in' turns out to 190 * be bad */ 191 } 192 memcpy(buf, seed, SHA_DIGEST_LENGTH); 193 memcpy(buf2, seed, SHA_DIGEST_LENGTH); 194 /* precompute "SEED + 1" for step 7: */ 195 for (i = SHA_DIGEST_LENGTH - 1; i >= 0; i--) { 196 buf[i]++; 197 if (buf[i] != 0) 198 break; 199 } 200 201 /* step 2 */ 202 EVP_Digest(seed, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL); 203 EVP_Digest(buf, SHA_DIGEST_LENGTH, buf2, NULL, HASH, NULL); 204 for (i = 0; i < SHA_DIGEST_LENGTH; i++) 205 md[i] ^= buf2[i]; 206 207 /* step 3 */ 208 md[0] |= 0x80; 209 md[SHA_DIGEST_LENGTH - 1] |= 0x01; 210 if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, q)) 211 goto err; 212 213 /* step 4 */ 214 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, 215 seed_is_random, cb); 216 if (r > 0) 217 break; 218 if (r != 0) 219 goto err; 220 221 /* do a callback call */ 222 /* step 5 */ 223 } 224 225 if (!BN_GENCB_call(cb, 2, 0)) 226 goto err; 227 if (!BN_GENCB_call(cb, 3, 0)) 228 goto err; 229 230 /* step 6 */ 231 counter = 0; 232 /* "offset = 2" */ 233 234 n = (bits - 1) / 160; 235 b = (bits - 1) - n * 160; 236 237 for (;;) { 238 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) 239 goto err; 240 241 /* step 7 */ 242 BN_zero(W); 243 /* now 'buf' contains "SEED + offset - 1" */ 244 for (k = 0; k <= n; k++) { 245 /* 246 * obtain "SEED + offset + k" by incrementing: 247 */ 248 for (i = SHA_DIGEST_LENGTH - 1; i >= 0; i--) { 249 buf[i]++; 250 if (buf[i] != 0) 251 break; 252 } 253 254 EVP_Digest(buf, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL); 255 256 /* step 8 */ 257 if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, r0)) 258 goto err; 259 if (!BN_lshift(r0, r0, 160 * k)) 260 goto err; 261 if (!BN_add(W, W, r0)) 262 goto err; 263 } 264 265 /* more of step 8 */ 266 if (!BN_mask_bits(W, bits - 1)) 267 goto err; 268 if (!BN_copy(X, W)) 269 goto err; 270 if (!BN_add(X, X, test)) 271 goto err; 272 273 /* step 9 */ 274 if (!BN_lshift1(r0, q)) 275 goto err; 276 if (!BN_mod(c, X, r0, ctx)) 277 goto err; 278 if (!BN_sub(r0, c, BN_value_one())) 279 goto err; 280 if (!BN_sub(p, X, r0)) 281 goto err; 282 283 /* step 10 */ 284 if (BN_cmp(p, test) >= 0) { 285 /* step 11 */ 286 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb); 287 if (r > 0) 288 goto end; /* found it */ 289 if (r != 0) 290 goto err; 291 } 292 293 /* step 13 */ 294 counter++; 295 /* "offset = offset + n + 1" */ 296 297 /* step 14 */ 298 if (counter >= 4096) 299 break; 300 } 301 } 302 end: 303 if (!BN_GENCB_call(cb, 2, 1)) 304 goto err; 305 306 /* We now need to generate g */ 307 /* Set r0=(p-1)/q */ 308 if (!BN_sub(test, p, BN_value_one())) 309 goto err; 310 if (!BN_div(r0, NULL, test, q, ctx)) 311 goto err; 312 313 if (!BN_set_word(test, h)) 314 goto err; 315 if (!BN_MONT_CTX_set(mont, p, ctx)) 316 goto err; 317 318 for (;;) { 319 /* g=test^r0%p */ 320 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) 321 goto err; 322 if (!BN_is_one(g)) 323 break; 324 if (!BN_add(test, test, BN_value_one())) 325 goto err; 326 h++; 327 } 328 329 if (!BN_GENCB_call(cb, 3, 1)) 330 goto err; 331 332 ok = 1; 333 err: 334 if (ok) { 335 if (ret->p) 336 BN_free(ret->p); 337 if (ret->q) 338 BN_free(ret->q); 339 if (ret->g) 340 BN_free(ret->g); 341 ret->p = BN_dup(p); 342 ret->q = BN_dup(q); 343 ret->g = BN_dup(g); 344 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { 345 ok = 0; 346 goto err; 347 } 348 if (seed_in != NULL) 349 memcpy(seed_in, seed, 20); 350 if (counter_ret != NULL) 351 *counter_ret = counter; 352 if (h_ret != NULL) 353 *h_ret = h; 354 } 355 if (ctx) { 356 BN_CTX_end(ctx); 357 BN_CTX_free(ctx); 358 } 359 if (mont != NULL) 360 BN_MONT_CTX_free(mont); 361 return ok; 362} 363# endif 364#endif 365