1 /* ssl/tls_srp.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) 2004-2011 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 #include "ssl_locl.h" 60 #ifndef OPENSSL_NO_SRP 61 62 #include <openssl/rand.h> 63 #include <openssl/srp.h> 64 #include <openssl/err.h> 65 66 int SSL_CTX_SRP_CTX_free(struct ssl_ctx_st *ctx) 67 { 68 if (ctx == NULL) 69 return 0; 70 OPENSSL_free(ctx->srp_ctx.login); 71 BN_free(ctx->srp_ctx.N); 72 BN_free(ctx->srp_ctx.g); 73 BN_free(ctx->srp_ctx.s); 74 BN_free(ctx->srp_ctx.B); 75 BN_free(ctx->srp_ctx.A); 76 BN_free(ctx->srp_ctx.a); 77 BN_free(ctx->srp_ctx.b); 78 BN_free(ctx->srp_ctx.v); 79 ctx->srp_ctx.TLS_ext_srp_username_callback = NULL; 80 ctx->srp_ctx.SRP_cb_arg = NULL; 81 ctx->srp_ctx.SRP_verify_param_callback = NULL; 82 ctx->srp_ctx.SRP_give_srp_client_pwd_callback = NULL; 83 ctx->srp_ctx.N = NULL; 84 ctx->srp_ctx.g = NULL; 85 ctx->srp_ctx.s = NULL; 86 ctx->srp_ctx.B = NULL; 87 ctx->srp_ctx.A = NULL; 88 ctx->srp_ctx.a = NULL; 89 ctx->srp_ctx.b = NULL; 90 ctx->srp_ctx.v = NULL; 91 ctx->srp_ctx.login = NULL; 92 ctx->srp_ctx.info = NULL; 93 ctx->srp_ctx.strength = SRP_MINIMAL_N; 94 ctx->srp_ctx.srp_Mask = 0; 95 return (1); 96 } 97 98 int SSL_SRP_CTX_free(struct ssl_st *s) 99 { 100 if (s == NULL) 101 return 0; 102 OPENSSL_free(s->srp_ctx.login); 103 BN_free(s->srp_ctx.N); 104 BN_free(s->srp_ctx.g); 105 BN_free(s->srp_ctx.s); 106 BN_free(s->srp_ctx.B); 107 BN_free(s->srp_ctx.A); 108 BN_free(s->srp_ctx.a); 109 BN_free(s->srp_ctx.b); 110 BN_free(s->srp_ctx.v); 111 s->srp_ctx.TLS_ext_srp_username_callback = NULL; 112 s->srp_ctx.SRP_cb_arg = NULL; 113 s->srp_ctx.SRP_verify_param_callback = NULL; 114 s->srp_ctx.SRP_give_srp_client_pwd_callback = NULL; 115 s->srp_ctx.N = NULL; 116 s->srp_ctx.g = NULL; 117 s->srp_ctx.s = NULL; 118 s->srp_ctx.B = NULL; 119 s->srp_ctx.A = NULL; 120 s->srp_ctx.a = NULL; 121 s->srp_ctx.b = NULL; 122 s->srp_ctx.v = NULL; 123 s->srp_ctx.login = NULL; 124 s->srp_ctx.info = NULL; 125 s->srp_ctx.strength = SRP_MINIMAL_N; 126 s->srp_ctx.srp_Mask = 0; 127 return (1); 128 } 129 130 int SSL_SRP_CTX_init(struct ssl_st *s) 131 { 132 SSL_CTX *ctx; 133 134 if ((s == NULL) || ((ctx = s->ctx) == NULL)) 135 return 0; 136 s->srp_ctx.SRP_cb_arg = ctx->srp_ctx.SRP_cb_arg; 137 /* set client Hello login callback */ 138 s->srp_ctx.TLS_ext_srp_username_callback = ctx->srp_ctx.TLS_ext_srp_username_callback; 139 /* set SRP N/g param callback for verification */ 140 s->srp_ctx.SRP_verify_param_callback = ctx->srp_ctx.SRP_verify_param_callback; 141 /* set SRP client passwd callback */ 142 s->srp_ctx.SRP_give_srp_client_pwd_callback = ctx->srp_ctx.SRP_give_srp_client_pwd_callback; 143 144 s->srp_ctx.N = NULL; 145 s->srp_ctx.g = NULL; 146 s->srp_ctx.s = NULL; 147 s->srp_ctx.B = NULL; 148 s->srp_ctx.A = NULL; 149 s->srp_ctx.a = NULL; 150 s->srp_ctx.b = NULL; 151 s->srp_ctx.v = NULL; 152 s->srp_ctx.login = NULL; 153 s->srp_ctx.info = ctx->srp_ctx.info; 154 s->srp_ctx.strength = ctx->srp_ctx.strength; 155 156 if (((ctx->srp_ctx.N != NULL) && 157 ((s->srp_ctx.N = BN_dup(ctx->srp_ctx.N)) == NULL)) || 158 ((ctx->srp_ctx.g != NULL) && 159 ((s->srp_ctx.g = BN_dup(ctx->srp_ctx.g)) == NULL)) || 160 ((ctx->srp_ctx.s != NULL) && 161 ((s->srp_ctx.s = BN_dup(ctx->srp_ctx.s)) == NULL)) || 162 ((ctx->srp_ctx.B != NULL) && 163 ((s->srp_ctx.B = BN_dup(ctx->srp_ctx.B)) == NULL)) || 164 ((ctx->srp_ctx.A != NULL) && 165 ((s->srp_ctx.A = BN_dup(ctx->srp_ctx.A)) == NULL)) || 166 ((ctx->srp_ctx.a != NULL) && 167 ((s->srp_ctx.a = BN_dup(ctx->srp_ctx.a)) == NULL)) || 168 ((ctx->srp_ctx.v != NULL) && 169 ((s->srp_ctx.v = BN_dup(ctx->srp_ctx.v)) == NULL)) || 170 ((ctx->srp_ctx.b != NULL) && 171 ((s->srp_ctx.b = BN_dup(ctx->srp_ctx.b)) == NULL))) 172 { 173 SSLerr(SSL_F_SSL_SRP_CTX_INIT,ERR_R_BN_LIB); 174 goto err; 175 } 176 if ((ctx->srp_ctx.login != NULL) && 177 ((s->srp_ctx.login = BUF_strdup(ctx->srp_ctx.login)) == NULL)) 178 { 179 SSLerr(SSL_F_SSL_SRP_CTX_INIT,ERR_R_INTERNAL_ERROR); 180 goto err; 181 } 182 s->srp_ctx.srp_Mask = ctx->srp_ctx.srp_Mask; 183 184 return (1); 185 err: 186 OPENSSL_free(s->srp_ctx.login); 187 BN_free(s->srp_ctx.N); 188 BN_free(s->srp_ctx.g); 189 BN_free(s->srp_ctx.s); 190 BN_free(s->srp_ctx.B); 191 BN_free(s->srp_ctx.A); 192 BN_free(s->srp_ctx.a); 193 BN_free(s->srp_ctx.b); 194 BN_free(s->srp_ctx.v); 195 return (0); 196 } 197 198 int SSL_CTX_SRP_CTX_init(struct ssl_ctx_st *ctx) 199 { 200 if (ctx == NULL) 201 return 0; 202 203 ctx->srp_ctx.SRP_cb_arg = NULL; 204 /* set client Hello login callback */ 205 ctx->srp_ctx.TLS_ext_srp_username_callback = NULL; 206 /* set SRP N/g param callback for verification */ 207 ctx->srp_ctx.SRP_verify_param_callback = NULL; 208 /* set SRP client passwd callback */ 209 ctx->srp_ctx.SRP_give_srp_client_pwd_callback = NULL; 210 211 ctx->srp_ctx.N = NULL; 212 ctx->srp_ctx.g = NULL; 213 ctx->srp_ctx.s = NULL; 214 ctx->srp_ctx.B = NULL; 215 ctx->srp_ctx.A = NULL; 216 ctx->srp_ctx.a = NULL; 217 ctx->srp_ctx.b = NULL; 218 ctx->srp_ctx.v = NULL; 219 ctx->srp_ctx.login = NULL; 220 ctx->srp_ctx.srp_Mask = 0; 221 ctx->srp_ctx.info = NULL; 222 ctx->srp_ctx.strength = SRP_MINIMAL_N; 223 224 return (1); 225 } 226 227 /* server side */ 228 int SSL_srp_server_param_with_username(SSL *s, int *ad) 229 { 230 unsigned char b[SSL_MAX_MASTER_KEY_LENGTH]; 231 int al; 232 233 *ad = SSL_AD_UNKNOWN_PSK_IDENTITY; 234 if ((s->srp_ctx.TLS_ext_srp_username_callback !=NULL) && 235 ((al = s->srp_ctx.TLS_ext_srp_username_callback(s, ad, s->srp_ctx.SRP_cb_arg))!=SSL_ERROR_NONE)) 236 return al; 237 238 *ad = SSL_AD_INTERNAL_ERROR; 239 if ((s->srp_ctx.N == NULL) || 240 (s->srp_ctx.g == NULL) || 241 (s->srp_ctx.s == NULL) || 242 (s->srp_ctx.v == NULL)) 243 return SSL3_AL_FATAL; 244 245 if (RAND_bytes(b, sizeof(b)) <= 0) 246 return SSL3_AL_FATAL; 247 s->srp_ctx.b = BN_bin2bn(b,sizeof(b),NULL); 248 OPENSSL_cleanse(b,sizeof(b)); 249 250 /* Calculate: B = (kv + g^b) % N */ 251 252 return ((s->srp_ctx.B = SRP_Calc_B(s->srp_ctx.b, s->srp_ctx.N, s->srp_ctx.g, s->srp_ctx.v)) != NULL)? 253 SSL_ERROR_NONE:SSL3_AL_FATAL; 254 } 255 256 /* If the server just has the raw password, make up a verifier entry on the fly */ 257 int SSL_set_srp_server_param_pw(SSL *s, const char *user, const char *pass, const char *grp) 258 { 259 SRP_gN *GN = SRP_get_default_gN(grp); 260 if(GN == NULL) return -1; 261 s->srp_ctx.N = BN_dup(GN->N); 262 s->srp_ctx.g = BN_dup(GN->g); 263 if(s->srp_ctx.v != NULL) 264 { 265 BN_clear_free(s->srp_ctx.v); 266 s->srp_ctx.v = NULL; 267 } 268 if(s->srp_ctx.s != NULL) 269 { 270 BN_clear_free(s->srp_ctx.s); 271 s->srp_ctx.s = NULL; 272 } 273 if(!SRP_create_verifier_BN(user, pass, &s->srp_ctx.s, &s->srp_ctx.v, GN->N, GN->g)) return -1; 274 275 return 1; 276 } 277 278 int SSL_set_srp_server_param(SSL *s, const BIGNUM *N, const BIGNUM *g, 279 BIGNUM *sa, BIGNUM *v, char *info) 280 { 281 if (N!= NULL) 282 { 283 if (s->srp_ctx.N != NULL) 284 { 285 if (!BN_copy(s->srp_ctx.N,N)) 286 { 287 BN_free(s->srp_ctx.N); 288 s->srp_ctx.N = NULL; 289 } 290 } 291 else 292 s->srp_ctx.N = BN_dup(N); 293 } 294 if (g!= NULL) 295 { 296 if (s->srp_ctx.g != NULL) 297 { 298 if (!BN_copy(s->srp_ctx.g,g)) 299 { 300 BN_free(s->srp_ctx.g); 301 s->srp_ctx.g = NULL; 302 } 303 } 304 else 305 s->srp_ctx.g = BN_dup(g); 306 } 307 if (sa!= NULL) 308 { 309 if (s->srp_ctx.s != NULL) 310 { 311 if (!BN_copy(s->srp_ctx.s,sa)) 312 { 313 BN_free(s->srp_ctx.s); 314 s->srp_ctx.s = NULL; 315 } 316 } 317 else 318 s->srp_ctx.s = BN_dup(sa); 319 } 320 if (v!= NULL) 321 { 322 if (s->srp_ctx.v != NULL) 323 { 324 if (!BN_copy(s->srp_ctx.v,v)) 325 { 326 BN_free(s->srp_ctx.v); 327 s->srp_ctx.v = NULL; 328 } 329 } 330 else 331 s->srp_ctx.v = BN_dup(v); 332 } 333 s->srp_ctx.info = info; 334 335 if (!(s->srp_ctx.N) || 336 !(s->srp_ctx.g) || 337 !(s->srp_ctx.s) || 338 !(s->srp_ctx.v)) 339 return -1; 340 341 return 1; 342 } 343 344 int SRP_generate_server_master_secret(SSL *s,unsigned char *master_key) 345 { 346 BIGNUM *K = NULL, *u = NULL; 347 int ret = -1, tmp_len; 348 unsigned char *tmp = NULL; 349 350 if (!SRP_Verify_A_mod_N(s->srp_ctx.A,s->srp_ctx.N)) 351 goto err; 352 if (!(u = SRP_Calc_u(s->srp_ctx.A,s->srp_ctx.B,s->srp_ctx.N))) 353 goto err; 354 if (!(K = SRP_Calc_server_key(s->srp_ctx.A, s->srp_ctx.v, u, s->srp_ctx.b, s->srp_ctx.N))) 355 goto err; 356 357 tmp_len = BN_num_bytes(K); 358 if ((tmp = OPENSSL_malloc(tmp_len)) == NULL) 359 goto err; 360 BN_bn2bin(K, tmp); 361 ret = s->method->ssl3_enc->generate_master_secret(s,master_key,tmp,tmp_len); 362 err: 363 if (tmp) 364 { 365 OPENSSL_cleanse(tmp,tmp_len) ; 366 OPENSSL_free(tmp); 367 } 368 BN_clear_free(K); 369 BN_clear_free(u); 370 return ret; 371 } 372 373 /* client side */ 374 int SRP_generate_client_master_secret(SSL *s,unsigned char *master_key) 375 { 376 BIGNUM *x = NULL, *u = NULL, *K = NULL; 377 int ret = -1, tmp_len; 378 char *passwd = NULL; 379 unsigned char *tmp = NULL; 380 381 /* Checks if b % n == 0 382 */ 383 if (SRP_Verify_B_mod_N(s->srp_ctx.B,s->srp_ctx.N)==0) goto err; 384 if (!(u = SRP_Calc_u(s->srp_ctx.A,s->srp_ctx.B,s->srp_ctx.N))) goto err; 385 if (s->srp_ctx.SRP_give_srp_client_pwd_callback == NULL) goto err; 386 if (!(passwd = s->srp_ctx.SRP_give_srp_client_pwd_callback(s, s->srp_ctx.SRP_cb_arg))) goto err; 387 if (!(x = SRP_Calc_x(s->srp_ctx.s,s->srp_ctx.login,passwd))) goto err; 388 if (!(K = SRP_Calc_client_key(s->srp_ctx.N, s->srp_ctx.B, s->srp_ctx.g, x, s->srp_ctx.a, u))) goto err; 389 390 tmp_len = BN_num_bytes(K); 391 if ((tmp = OPENSSL_malloc(tmp_len)) == NULL) goto err; 392 BN_bn2bin(K, tmp); 393 ret = s->method->ssl3_enc->generate_master_secret(s,master_key,tmp,tmp_len); 394 err: 395 if (tmp) 396 { 397 OPENSSL_cleanse(tmp,tmp_len) ; 398 OPENSSL_free(tmp); 399 } 400 BN_clear_free(K); 401 BN_clear_free(x); 402 if (passwd) 403 { 404 OPENSSL_cleanse(passwd,strlen(passwd)) ; 405 OPENSSL_free(passwd); 406 } 407 BN_clear_free(u); 408 return ret; 409 } 410 411 int srp_verify_server_param(SSL *s, int *al) 412 { 413 SRP_CTX *srp = &s->srp_ctx; 414 /* Sanity check parameters: we can quickly check B % N == 0 415 * by checking B != 0 since B < N 416 */ 417 if (BN_ucmp(srp->g, srp->N) >=0 || BN_ucmp(srp->B, srp->N) >= 0 418 || BN_is_zero(srp->B)) 419 { 420 *al = SSL3_AD_ILLEGAL_PARAMETER; 421 return 0; 422 } 423 424 if (BN_num_bits(srp->N) < srp->strength) 425 { 426 *al = TLS1_AD_INSUFFICIENT_SECURITY; 427 return 0; 428 } 429 430 if (srp->SRP_verify_param_callback) 431 { 432 if (srp->SRP_verify_param_callback(s, srp->SRP_cb_arg) <= 0) 433 { 434 *al = TLS1_AD_INSUFFICIENT_SECURITY; 435 return 0; 436 } 437 } 438 else if(!SRP_check_known_gN_param(srp->g, srp->N)) 439 { 440 *al = TLS1_AD_INSUFFICIENT_SECURITY; 441 return 0; 442 } 443 444 return 1; 445 } 446 447 448 int SRP_Calc_A_param(SSL *s) 449 { 450 unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH]; 451 452 RAND_bytes(rnd, sizeof(rnd)); 453 s->srp_ctx.a = BN_bin2bn(rnd, sizeof(rnd), s->srp_ctx.a); 454 OPENSSL_cleanse(rnd, sizeof(rnd)); 455 456 if (!(s->srp_ctx.A = SRP_Calc_A(s->srp_ctx.a,s->srp_ctx.N,s->srp_ctx.g))) 457 return -1; 458 459 return 1; 460 } 461 462 BIGNUM *SSL_get_srp_g(SSL *s) 463 { 464 if (s->srp_ctx.g != NULL) 465 return s->srp_ctx.g; 466 return s->ctx->srp_ctx.g; 467 } 468 469 BIGNUM *SSL_get_srp_N(SSL *s) 470 { 471 if (s->srp_ctx.N != NULL) 472 return s->srp_ctx.N; 473 return s->ctx->srp_ctx.N; 474 } 475 476 char *SSL_get_srp_username(SSL *s) 477 { 478 if (s->srp_ctx.login != NULL) 479 return s->srp_ctx.login; 480 return s->ctx->srp_ctx.login; 481 } 482 483 char *SSL_get_srp_userinfo(SSL *s) 484 { 485 if (s->srp_ctx.info != NULL) 486 return s->srp_ctx.info; 487 return s->ctx->srp_ctx.info; 488 } 489 490 #define tls1_ctx_ctrl ssl3_ctx_ctrl 491 #define tls1_ctx_callback_ctrl ssl3_ctx_callback_ctrl 492 493 int SSL_CTX_set_srp_username(SSL_CTX *ctx,char *name) 494 { 495 return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_USERNAME,0,name); 496 } 497 498 int SSL_CTX_set_srp_password(SSL_CTX *ctx,char *password) 499 { 500 return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_PASSWORD,0,password); 501 } 502 503 int SSL_CTX_set_srp_strength(SSL_CTX *ctx, int strength) 504 { 505 return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_STRENGTH, strength, 506 NULL); 507 } 508 509 int SSL_CTX_set_srp_verify_param_callback(SSL_CTX *ctx, int (*cb)(SSL *,void *)) 510 { 511 return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_SRP_VERIFY_PARAM_CB, 512 (void (*)(void))cb); 513 } 514 515 int SSL_CTX_set_srp_cb_arg(SSL_CTX *ctx, void *arg) 516 { 517 return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_SRP_ARG,0,arg); 518 } 519 520 int SSL_CTX_set_srp_username_callback(SSL_CTX *ctx, 521 int (*cb)(SSL *,int *,void *)) 522 { 523 return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_USERNAME_CB, 524 (void (*)(void))cb); 525 } 526 527 int SSL_CTX_set_srp_client_pwd_callback(SSL_CTX *ctx, char *(*cb)(SSL *,void *)) 528 { 529 return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_SRP_GIVE_CLIENT_PWD_CB, 530 (void (*)(void))cb); 531 } 532 533 #endif 534
