1 /* crypto/srp/srp_lib.c */ 2 /* Written by Christophe Renou (christophe.renou (at) edelweb.fr) with 3 * the precious help of Peter Sylvester (peter.sylvester (at) edelweb.fr) 4 * for the EdelKey project and contributed to the OpenSSL project 2004. 5 */ 6 /* ==================================================================== 7 * Copyright (c) 2004 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * licensing (at) OpenSSL.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay (at) cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh (at) cryptsoft.com). 57 * 58 */ 59 #ifndef OPENSSL_NO_SRP 60 #include "cryptlib.h" 61 #include "srp_lcl.h" 62 #include <openssl/srp.h> 63 #include <openssl/evp.h> 64 65 #if (BN_BYTES == 8) 66 # if (defined(_WIN32) || defined(_WIN64)) && !defined(__MINGW32__) 67 # define bn_pack4(a1,a2,a3,a4) ((a1##UI64<<48)|(a2##UI64<<32)|(a3##UI64<<16)|a4##UI64) 68 # elif defined(__arch64__) 69 # define bn_pack4(a1,a2,a3,a4) ((a1##UL<<48)|(a2##UL<<32)|(a3##UL<<16)|a4##UL) 70 # else 71 # define bn_pack4(a1,a2,a3,a4) ((a1##ULL<<48)|(a2##ULL<<32)|(a3##ULL<<16)|a4##ULL) 72 # endif 73 #elif (BN_BYTES == 4) 74 # define bn_pack4(a1,a2,a3,a4) ((a3##UL<<16)|a4##UL), ((a1##UL<<16)|a2##UL) 75 #else 76 # error "unsupported BN_BYTES" 77 #endif 78 79 80 #include "srp_grps.h" 81 82 static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g) 83 { 84 /* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */ 85 86 unsigned char digest[SHA_DIGEST_LENGTH]; 87 unsigned char *tmp; 88 EVP_MD_CTX ctxt; 89 int longg ; 90 int longN = BN_num_bytes(N); 91 92 if (BN_ucmp(g, N) >= 0) 93 return NULL; 94 95 if ((tmp = OPENSSL_malloc(longN)) == NULL) 96 return NULL; 97 BN_bn2bin(N,tmp) ; 98 99 EVP_MD_CTX_init(&ctxt); 100 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); 101 EVP_DigestUpdate(&ctxt, tmp, longN); 102 103 memset(tmp, 0, longN); 104 longg = BN_bn2bin(g,tmp) ; 105 /* use the zeros behind to pad on left */ 106 EVP_DigestUpdate(&ctxt, tmp + longg, longN-longg); 107 EVP_DigestUpdate(&ctxt, tmp, longg); 108 OPENSSL_free(tmp); 109 110 EVP_DigestFinal_ex(&ctxt, digest, NULL); 111 EVP_MD_CTX_cleanup(&ctxt); 112 return BN_bin2bn(digest, sizeof(digest), NULL); 113 } 114 115 BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N) 116 { 117 /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */ 118 119 BIGNUM *u; 120 unsigned char cu[SHA_DIGEST_LENGTH]; 121 unsigned char *cAB; 122 EVP_MD_CTX ctxt; 123 int longN; 124 if ((A == NULL) ||(B == NULL) || (N == NULL)) 125 return NULL; 126 127 if (BN_ucmp(A, N) >= 0 || BN_ucmp(B, N) >= 0) 128 return NULL; 129 130 longN= BN_num_bytes(N); 131 132 if ((cAB = OPENSSL_malloc(2*longN)) == NULL) 133 return NULL; 134 135 memset(cAB, 0, longN); 136 137 EVP_MD_CTX_init(&ctxt); 138 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); 139 EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(A,cAB+longN), longN); 140 EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(B,cAB+longN), longN); 141 OPENSSL_free(cAB); 142 EVP_DigestFinal_ex(&ctxt, cu, NULL); 143 EVP_MD_CTX_cleanup(&ctxt); 144 145 if (!(u = BN_bin2bn(cu, sizeof(cu), NULL))) 146 return NULL; 147 if (!BN_is_zero(u)) 148 return u; 149 BN_free(u); 150 return NULL; 151 } 152 153 BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b, BIGNUM *N) 154 { 155 BIGNUM *tmp = NULL, *S = NULL; 156 BN_CTX *bn_ctx; 157 158 if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL) 159 return NULL; 160 161 if ((bn_ctx = BN_CTX_new()) == NULL || 162 (tmp = BN_new()) == NULL || 163 (S = BN_new()) == NULL ) 164 goto err; 165 166 /* S = (A*v**u) ** b */ 167 168 if (!BN_mod_exp(tmp,v,u,N,bn_ctx)) 169 goto err; 170 if (!BN_mod_mul(tmp,A,tmp,N,bn_ctx)) 171 goto err; 172 if (!BN_mod_exp(S,tmp,b,N,bn_ctx)) 173 goto err; 174 err: 175 BN_CTX_free(bn_ctx); 176 BN_clear_free(tmp); 177 return S; 178 } 179 180 BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v) 181 { 182 BIGNUM *kv = NULL, *gb = NULL; 183 BIGNUM *B = NULL, *k = NULL; 184 BN_CTX *bn_ctx; 185 186 if (b == NULL || N == NULL || g == NULL || v == NULL || 187 (bn_ctx = BN_CTX_new()) == NULL) 188 return NULL; 189 190 if ( (kv = BN_new()) == NULL || 191 (gb = BN_new()) == NULL || 192 (B = BN_new())== NULL) 193 goto err; 194 195 /* B = g**b + k*v */ 196 197 if (!BN_mod_exp(gb,g,b,N,bn_ctx) || 198 !(k = srp_Calc_k(N,g)) || 199 !BN_mod_mul(kv,v,k,N,bn_ctx) || 200 !BN_mod_add(B,gb,kv,N,bn_ctx)) 201 { 202 BN_free(B); 203 B = NULL; 204 } 205 err: 206 BN_CTX_free(bn_ctx); 207 BN_clear_free(kv); 208 BN_clear_free(gb); 209 BN_free(k); 210 return B; 211 } 212 213 BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass) 214 { 215 unsigned char dig[SHA_DIGEST_LENGTH]; 216 EVP_MD_CTX ctxt; 217 unsigned char *cs; 218 219 if ((s == NULL) || 220 (user == NULL) || 221 (pass == NULL)) 222 return NULL; 223 224 if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL) 225 return NULL; 226 227 EVP_MD_CTX_init(&ctxt); 228 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); 229 EVP_DigestUpdate(&ctxt, user, strlen(user)); 230 EVP_DigestUpdate(&ctxt, ":", 1); 231 EVP_DigestUpdate(&ctxt, pass, strlen(pass)); 232 EVP_DigestFinal_ex(&ctxt, dig, NULL); 233 234 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); 235 BN_bn2bin(s,cs); 236 EVP_DigestUpdate(&ctxt, cs, BN_num_bytes(s)); 237 OPENSSL_free(cs); 238 EVP_DigestUpdate(&ctxt, dig, sizeof(dig)); 239 EVP_DigestFinal_ex(&ctxt, dig, NULL); 240 EVP_MD_CTX_cleanup(&ctxt); 241 242 return BN_bin2bn(dig, sizeof(dig), NULL); 243 } 244 245 BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g) 246 { 247 BN_CTX *bn_ctx; 248 BIGNUM * A = NULL; 249 250 if (a == NULL || N == NULL || g == NULL || 251 (bn_ctx = BN_CTX_new()) == NULL) 252 return NULL; 253 254 if ((A = BN_new()) != NULL && 255 !BN_mod_exp(A,g,a,N,bn_ctx)) 256 { 257 BN_free(A); 258 A = NULL; 259 } 260 BN_CTX_free(bn_ctx); 261 return A; 262 } 263 264 265 BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x, BIGNUM *a, BIGNUM *u) 266 { 267 BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL , *k = NULL, *K = NULL; 268 BN_CTX *bn_ctx; 269 270 if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL || a == NULL || 271 (bn_ctx = BN_CTX_new()) == NULL) 272 return NULL; 273 274 if ((tmp = BN_new()) == NULL || 275 (tmp2 = BN_new())== NULL || 276 (tmp3 = BN_new())== NULL || 277 (K = BN_new()) == NULL) 278 goto err; 279 280 if (!BN_mod_exp(tmp,g,x,N,bn_ctx)) 281 goto err; 282 if (!(k = srp_Calc_k(N,g))) 283 goto err; 284 if (!BN_mod_mul(tmp2,tmp,k,N,bn_ctx)) 285 goto err; 286 if (!BN_mod_sub(tmp,B,tmp2,N,bn_ctx)) 287 goto err; 288 289 if (!BN_mod_mul(tmp3,u,x,N,bn_ctx)) 290 goto err; 291 if (!BN_mod_add(tmp2,a,tmp3,N,bn_ctx)) 292 goto err; 293 if (!BN_mod_exp(K,tmp,tmp2,N,bn_ctx)) 294 goto err; 295 296 err : 297 BN_CTX_free(bn_ctx); 298 BN_clear_free(tmp); 299 BN_clear_free(tmp2); 300 BN_clear_free(tmp3); 301 BN_free(k); 302 return K; 303 } 304 305 int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N) 306 { 307 BIGNUM *r; 308 BN_CTX *bn_ctx; 309 int ret = 0; 310 311 if (B == NULL || N == NULL || 312 (bn_ctx = BN_CTX_new()) == NULL) 313 return 0; 314 315 if ((r = BN_new()) == NULL) 316 goto err; 317 /* Checks if B % N == 0 */ 318 if (!BN_nnmod(r,B,N,bn_ctx)) 319 goto err; 320 ret = !BN_is_zero(r); 321 err: 322 BN_CTX_free(bn_ctx); 323 BN_free(r); 324 return ret; 325 } 326 327 int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N) 328 { 329 /* Checks if A % N == 0 */ 330 return SRP_Verify_B_mod_N(A,N) ; 331 } 332 333 334 /* Check if G and N are kwown parameters. 335 The values have been generated from the ietf-tls-srp draft version 8 336 */ 337 char *SRP_check_known_gN_param(BIGNUM *g, BIGNUM *N) 338 { 339 size_t i; 340 if ((g == NULL) || (N == NULL)) 341 return 0; 342 343 srp_bn_print(g); 344 srp_bn_print(N); 345 346 for(i = 0; i < KNOWN_GN_NUMBER; i++) 347 { 348 if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0) 349 return knowngN[i].id; 350 } 351 return NULL; 352 } 353 354 SRP_gN *SRP_get_default_gN(const char *id) 355 { 356 size_t i; 357 358 if (id == NULL) 359 return knowngN; 360 for(i = 0; i < KNOWN_GN_NUMBER; i++) 361 { 362 if (strcmp(knowngN[i].id, id)==0) 363 return knowngN + i; 364 } 365 return NULL; 366 } 367 #endif 368
