ssl/tls_srp.c

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