Alexandre Lision | f26d3e5 | 2014-04-14 16:22:31 -0400 | [diff] [blame^] | 1 | /* crypto/srp/srp_lib.c */ |
| 2 | /* Written by Christophe Renou (christophe.renou@edelweb.fr) with |
| 3 | * the precious help of Peter Sylvester (peter.sylvester@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@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@cryptsoft.com). This product includes software written by Tim |
| 56 | * Hudson (tjh@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 ((tmp = OPENSSL_malloc(longN)) == NULL) |
| 93 | return NULL; |
| 94 | BN_bn2bin(N,tmp) ; |
| 95 | |
| 96 | EVP_MD_CTX_init(&ctxt); |
| 97 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); |
| 98 | EVP_DigestUpdate(&ctxt, tmp, longN); |
| 99 | |
| 100 | memset(tmp, 0, longN); |
| 101 | longg = BN_bn2bin(g,tmp) ; |
| 102 | /* use the zeros behind to pad on left */ |
| 103 | EVP_DigestUpdate(&ctxt, tmp + longg, longN-longg); |
| 104 | EVP_DigestUpdate(&ctxt, tmp, longg); |
| 105 | OPENSSL_free(tmp); |
| 106 | |
| 107 | EVP_DigestFinal_ex(&ctxt, digest, NULL); |
| 108 | EVP_MD_CTX_cleanup(&ctxt); |
| 109 | return BN_bin2bn(digest, sizeof(digest), NULL); |
| 110 | } |
| 111 | |
| 112 | BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N) |
| 113 | { |
| 114 | /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */ |
| 115 | |
| 116 | BIGNUM *u; |
| 117 | unsigned char cu[SHA_DIGEST_LENGTH]; |
| 118 | unsigned char *cAB; |
| 119 | EVP_MD_CTX ctxt; |
| 120 | int longN; |
| 121 | if ((A == NULL) ||(B == NULL) || (N == NULL)) |
| 122 | return NULL; |
| 123 | |
| 124 | longN= BN_num_bytes(N); |
| 125 | |
| 126 | if ((cAB = OPENSSL_malloc(2*longN)) == NULL) |
| 127 | return NULL; |
| 128 | |
| 129 | memset(cAB, 0, longN); |
| 130 | |
| 131 | EVP_MD_CTX_init(&ctxt); |
| 132 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); |
| 133 | EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(A,cAB+longN), longN); |
| 134 | EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(B,cAB+longN), longN); |
| 135 | OPENSSL_free(cAB); |
| 136 | EVP_DigestFinal_ex(&ctxt, cu, NULL); |
| 137 | EVP_MD_CTX_cleanup(&ctxt); |
| 138 | |
| 139 | if (!(u = BN_bin2bn(cu, sizeof(cu), NULL))) |
| 140 | return NULL; |
| 141 | if (!BN_is_zero(u)) |
| 142 | return u; |
| 143 | BN_free(u); |
| 144 | return NULL; |
| 145 | } |
| 146 | |
| 147 | BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b, BIGNUM *N) |
| 148 | { |
| 149 | BIGNUM *tmp = NULL, *S = NULL; |
| 150 | BN_CTX *bn_ctx; |
| 151 | |
| 152 | if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL) |
| 153 | return NULL; |
| 154 | |
| 155 | if ((bn_ctx = BN_CTX_new()) == NULL || |
| 156 | (tmp = BN_new()) == NULL || |
| 157 | (S = BN_new()) == NULL ) |
| 158 | goto err; |
| 159 | |
| 160 | /* S = (A*v**u) ** b */ |
| 161 | |
| 162 | if (!BN_mod_exp(tmp,v,u,N,bn_ctx)) |
| 163 | goto err; |
| 164 | if (!BN_mod_mul(tmp,A,tmp,N,bn_ctx)) |
| 165 | goto err; |
| 166 | if (!BN_mod_exp(S,tmp,b,N,bn_ctx)) |
| 167 | goto err; |
| 168 | err: |
| 169 | BN_CTX_free(bn_ctx); |
| 170 | BN_clear_free(tmp); |
| 171 | return S; |
| 172 | } |
| 173 | |
| 174 | BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v) |
| 175 | { |
| 176 | BIGNUM *kv = NULL, *gb = NULL; |
| 177 | BIGNUM *B = NULL, *k = NULL; |
| 178 | BN_CTX *bn_ctx; |
| 179 | |
| 180 | if (b == NULL || N == NULL || g == NULL || v == NULL || |
| 181 | (bn_ctx = BN_CTX_new()) == NULL) |
| 182 | return NULL; |
| 183 | |
| 184 | if ( (kv = BN_new()) == NULL || |
| 185 | (gb = BN_new()) == NULL || |
| 186 | (B = BN_new())== NULL) |
| 187 | goto err; |
| 188 | |
| 189 | /* B = g**b + k*v */ |
| 190 | |
| 191 | if (!BN_mod_exp(gb,g,b,N,bn_ctx) || |
| 192 | !(k = srp_Calc_k(N,g)) || |
| 193 | !BN_mod_mul(kv,v,k,N,bn_ctx) || |
| 194 | !BN_mod_add(B,gb,kv,N,bn_ctx)) |
| 195 | { |
| 196 | BN_free(B); |
| 197 | B = NULL; |
| 198 | } |
| 199 | err: |
| 200 | BN_CTX_free(bn_ctx); |
| 201 | BN_clear_free(kv); |
| 202 | BN_clear_free(gb); |
| 203 | BN_free(k); |
| 204 | return B; |
| 205 | } |
| 206 | |
| 207 | BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass) |
| 208 | { |
| 209 | unsigned char dig[SHA_DIGEST_LENGTH]; |
| 210 | EVP_MD_CTX ctxt; |
| 211 | unsigned char *cs; |
| 212 | |
| 213 | if ((s == NULL) || |
| 214 | (user == NULL) || |
| 215 | (pass == NULL)) |
| 216 | return NULL; |
| 217 | |
| 218 | if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL) |
| 219 | return NULL; |
| 220 | |
| 221 | EVP_MD_CTX_init(&ctxt); |
| 222 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); |
| 223 | EVP_DigestUpdate(&ctxt, user, strlen(user)); |
| 224 | EVP_DigestUpdate(&ctxt, ":", 1); |
| 225 | EVP_DigestUpdate(&ctxt, pass, strlen(pass)); |
| 226 | EVP_DigestFinal_ex(&ctxt, dig, NULL); |
| 227 | |
| 228 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); |
| 229 | BN_bn2bin(s,cs); |
| 230 | EVP_DigestUpdate(&ctxt, cs, BN_num_bytes(s)); |
| 231 | OPENSSL_free(cs); |
| 232 | EVP_DigestUpdate(&ctxt, dig, sizeof(dig)); |
| 233 | EVP_DigestFinal_ex(&ctxt, dig, NULL); |
| 234 | EVP_MD_CTX_cleanup(&ctxt); |
| 235 | |
| 236 | return BN_bin2bn(dig, sizeof(dig), NULL); |
| 237 | } |
| 238 | |
| 239 | BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g) |
| 240 | { |
| 241 | BN_CTX *bn_ctx; |
| 242 | BIGNUM * A = NULL; |
| 243 | |
| 244 | if (a == NULL || N == NULL || g == NULL || |
| 245 | (bn_ctx = BN_CTX_new()) == NULL) |
| 246 | return NULL; |
| 247 | |
| 248 | if ((A = BN_new()) != NULL && |
| 249 | !BN_mod_exp(A,g,a,N,bn_ctx)) |
| 250 | { |
| 251 | BN_free(A); |
| 252 | A = NULL; |
| 253 | } |
| 254 | BN_CTX_free(bn_ctx); |
| 255 | return A; |
| 256 | } |
| 257 | |
| 258 | |
| 259 | BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x, BIGNUM *a, BIGNUM *u) |
| 260 | { |
| 261 | BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL , *k = NULL, *K = NULL; |
| 262 | BN_CTX *bn_ctx; |
| 263 | |
| 264 | if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL || a == NULL || |
| 265 | (bn_ctx = BN_CTX_new()) == NULL) |
| 266 | return NULL; |
| 267 | |
| 268 | if ((tmp = BN_new()) == NULL || |
| 269 | (tmp2 = BN_new())== NULL || |
| 270 | (tmp3 = BN_new())== NULL || |
| 271 | (K = BN_new()) == NULL) |
| 272 | goto err; |
| 273 | |
| 274 | if (!BN_mod_exp(tmp,g,x,N,bn_ctx)) |
| 275 | goto err; |
| 276 | if (!(k = srp_Calc_k(N,g))) |
| 277 | goto err; |
| 278 | if (!BN_mod_mul(tmp2,tmp,k,N,bn_ctx)) |
| 279 | goto err; |
| 280 | if (!BN_mod_sub(tmp,B,tmp2,N,bn_ctx)) |
| 281 | goto err; |
| 282 | |
| 283 | if (!BN_mod_mul(tmp3,u,x,N,bn_ctx)) |
| 284 | goto err; |
| 285 | if (!BN_mod_add(tmp2,a,tmp3,N,bn_ctx)) |
| 286 | goto err; |
| 287 | if (!BN_mod_exp(K,tmp,tmp2,N,bn_ctx)) |
| 288 | goto err; |
| 289 | |
| 290 | err : |
| 291 | BN_CTX_free(bn_ctx); |
| 292 | BN_clear_free(tmp); |
| 293 | BN_clear_free(tmp2); |
| 294 | BN_clear_free(tmp3); |
| 295 | BN_free(k); |
| 296 | return K; |
| 297 | } |
| 298 | |
| 299 | int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N) |
| 300 | { |
| 301 | BIGNUM *r; |
| 302 | BN_CTX *bn_ctx; |
| 303 | int ret = 0; |
| 304 | |
| 305 | if (B == NULL || N == NULL || |
| 306 | (bn_ctx = BN_CTX_new()) == NULL) |
| 307 | return 0; |
| 308 | |
| 309 | if ((r = BN_new()) == NULL) |
| 310 | goto err; |
| 311 | /* Checks if B % N == 0 */ |
| 312 | if (!BN_nnmod(r,B,N,bn_ctx)) |
| 313 | goto err; |
| 314 | ret = !BN_is_zero(r); |
| 315 | err: |
| 316 | BN_CTX_free(bn_ctx); |
| 317 | BN_free(r); |
| 318 | return ret; |
| 319 | } |
| 320 | |
| 321 | int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N) |
| 322 | { |
| 323 | /* Checks if A % N == 0 */ |
| 324 | return SRP_Verify_B_mod_N(A,N) ; |
| 325 | } |
| 326 | |
| 327 | |
| 328 | /* Check if G and N are kwown parameters. |
| 329 | The values have been generated from the ietf-tls-srp draft version 8 |
| 330 | */ |
| 331 | char *SRP_check_known_gN_param(BIGNUM *g, BIGNUM *N) |
| 332 | { |
| 333 | size_t i; |
| 334 | if ((g == NULL) || (N == NULL)) |
| 335 | return 0; |
| 336 | |
| 337 | srp_bn_print(g); |
| 338 | srp_bn_print(N); |
| 339 | |
| 340 | for(i = 0; i < KNOWN_GN_NUMBER; i++) |
| 341 | { |
| 342 | if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0) |
| 343 | return knowngN[i].id; |
| 344 | } |
| 345 | return NULL; |
| 346 | } |
| 347 | |
| 348 | SRP_gN *SRP_get_default_gN(const char *id) |
| 349 | { |
| 350 | size_t i; |
| 351 | |
| 352 | if (id == NULL) |
| 353 | return knowngN; |
| 354 | for(i = 0; i < KNOWN_GN_NUMBER; i++) |
| 355 | { |
| 356 | if (strcmp(knowngN[i].id, id)==0) |
| 357 | return knowngN + i; |
| 358 | } |
| 359 | return NULL; |
| 360 | } |
| 361 | #endif |