ssl/tls_srp.c

   1 /* ssl/tls_srp.c */
   2 /*
   3  * Written by Christophe Renou (christophe.renou@edelweb.fr) with the
   4  * precious help of Peter Sylvester (peter.sylvester@edelweb.fr) for the
   5  * EdelKey project and contributed to the OpenSSL project 2004.
   6  */
   7 /* ====================================================================
   8  * Copyright (c) 2004-2011 The OpenSSL Project.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  *
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in
  19  *    the documentation and/or other materials provided with the
  20  *    distribution.
  21  *
  22  * 3. All advertising materials mentioning features or use of this
  23  *    software must display the following acknowledgment:
  24  *    "This product includes software developed by the OpenSSL Project
  25  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  26  *
  27  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  28  *    endorse or promote products derived from this software without
  29  *    prior written permission. For written permission, please contact
  30  *    licensing@OpenSSL.org.
  31  *
  32  * 5. Products derived from this software may not be called "OpenSSL"
  33  *    nor may "OpenSSL" appear in their names without prior written
  34  *    permission of the OpenSSL Project.
  35  *
  36  * 6. Redistributions of any form whatsoever must retain the following
  37  *    acknowledgment:
  38  *    "This product includes software developed by the OpenSSL Project
  39  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  42  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  44  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  45  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  46  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  47  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  48  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  50  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  51  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  52  * OF THE POSSIBILITY OF SUCH DAMAGE.
  53  * ====================================================================
  54  *
  55  * This product includes cryptographic software written by Eric Young
  56  * (eay@cryptsoft.com).  This product includes software written by Tim
  57  * Hudson (tjh@cryptsoft.com).
  58  *
  59  */
  60
  61 #include <openssl/crypto.h>
  62 #include <openssl/rand.h>
  63 #include <openssl/err.h>
  64 #include "ssl_locl.h"
  65
  66 #ifndef OPENSSL_NO_SRP
  67 #include <openssl/srp.h>
  68
  69 int SSL_CTX_SRP_CTX_free(struct ssl_ctx_st *ctx)
  70 {
  71     if (ctx == NULL)
  72         return 0;
  73     OPENSSL_free(ctx->srp_ctx.login);
  74     BN_free(ctx->srp_ctx.N);
  75     BN_free(ctx->srp_ctx.g);
  76     BN_free(ctx->srp_ctx.s);
  77     BN_free(ctx->srp_ctx.B);
  78     BN_free(ctx->srp_ctx.A);
  79     BN_free(ctx->srp_ctx.a);
  80     BN_free(ctx->srp_ctx.b);
  81     BN_free(ctx->srp_ctx.v);
  82     ctx->srp_ctx.TLS_ext_srp_username_callback = NULL;
  83     ctx->srp_ctx.SRP_cb_arg = NULL;
  84     ctx->srp_ctx.SRP_verify_param_callback = NULL;
  85     ctx->srp_ctx.SRP_give_srp_client_pwd_callback = NULL;
  86     ctx->srp_ctx.N = NULL;
  87     ctx->srp_ctx.g = NULL;
  88     ctx->srp_ctx.s = NULL;
  89     ctx->srp_ctx.B = NULL;
  90     ctx->srp_ctx.A = NULL;
  91     ctx->srp_ctx.a = NULL;
  92     ctx->srp_ctx.b = NULL;
  93     ctx->srp_ctx.v = NULL;
  94     ctx->srp_ctx.login = NULL;
  95     ctx->srp_ctx.info = NULL;
  96     ctx->srp_ctx.strength = SRP_MINIMAL_N;
  97     ctx->srp_ctx.srp_Mask = 0;
  98     return (1);
  99 }
 100
 101 int SSL_SRP_CTX_free(struct ssl_st *s)
 102 {
 103     if (s == NULL)
 104         return 0;
 105     OPENSSL_free(s->srp_ctx.login);
 106     BN_free(s->srp_ctx.N);
 107     BN_free(s->srp_ctx.g);
 108     BN_free(s->srp_ctx.s);
 109     BN_free(s->srp_ctx.B);
 110     BN_free(s->srp_ctx.A);
 111     BN_free(s->srp_ctx.a);
 112     BN_free(s->srp_ctx.b);
 113     BN_free(s->srp_ctx.v);
 114     s->srp_ctx.TLS_ext_srp_username_callback = NULL;
 115     s->srp_ctx.SRP_cb_arg = NULL;
 116     s->srp_ctx.SRP_verify_param_callback = NULL;
 117     s->srp_ctx.SRP_give_srp_client_pwd_callback = NULL;
 118     s->srp_ctx.N = NULL;
 119     s->srp_ctx.g = NULL;
 120     s->srp_ctx.s = NULL;
 121     s->srp_ctx.B = NULL;
 122     s->srp_ctx.A = NULL;
 123     s->srp_ctx.a = NULL;
 124     s->srp_ctx.b = NULL;
 125     s->srp_ctx.v = NULL;
 126     s->srp_ctx.login = NULL;
 127     s->srp_ctx.info = NULL;
 128     s->srp_ctx.strength = SRP_MINIMAL_N;
 129     s->srp_ctx.srp_Mask = 0;
 130     return (1);
 131 }
 132
 133 int SSL_SRP_CTX_init(struct ssl_st *s)
 134 {
 135     SSL_CTX *ctx;
 136
 137     if ((s == NULL) || ((ctx = s->ctx) == NULL))
 138         return 0;
 139     s->srp_ctx.SRP_cb_arg = ctx->srp_ctx.SRP_cb_arg;
 140     /* set client Hello login callback */
 141     s->srp_ctx.TLS_ext_srp_username_callback =
 142         ctx->srp_ctx.TLS_ext_srp_username_callback;
 143     /* set SRP N/g param callback for verification */
 144     s->srp_ctx.SRP_verify_param_callback =
 145         ctx->srp_ctx.SRP_verify_param_callback;
 146     /* set SRP client passwd callback */
 147     s->srp_ctx.SRP_give_srp_client_pwd_callback =
 148         ctx->srp_ctx.SRP_give_srp_client_pwd_callback;
 149
 150     s->srp_ctx.N = NULL;
 151     s->srp_ctx.g = NULL;
 152     s->srp_ctx.s = NULL;
 153     s->srp_ctx.B = NULL;
 154     s->srp_ctx.A = NULL;
 155     s->srp_ctx.a = NULL;
 156     s->srp_ctx.b = NULL;
 157     s->srp_ctx.v = NULL;
 158     s->srp_ctx.login = NULL;
 159     s->srp_ctx.info = ctx->srp_ctx.info;
 160     s->srp_ctx.strength = ctx->srp_ctx.strength;
 161
 162     if (((ctx->srp_ctx.N != NULL) &&
 163          ((s->srp_ctx.N = BN_dup(ctx->srp_ctx.N)) == NULL)) ||
 164         ((ctx->srp_ctx.g != NULL) &&
 165          ((s->srp_ctx.g = BN_dup(ctx->srp_ctx.g)) == NULL)) ||
 166         ((ctx->srp_ctx.s != NULL) &&
 167          ((s->srp_ctx.s = BN_dup(ctx->srp_ctx.s)) == NULL)) ||
 168         ((ctx->srp_ctx.B != NULL) &&
 169          ((s->srp_ctx.B = BN_dup(ctx->srp_ctx.B)) == NULL)) ||
 170         ((ctx->srp_ctx.A != NULL) &&
 171          ((s->srp_ctx.A = BN_dup(ctx->srp_ctx.A)) == NULL)) ||
 172         ((ctx->srp_ctx.a != NULL) &&
 173          ((s->srp_ctx.a = BN_dup(ctx->srp_ctx.a)) == NULL)) ||
 174         ((ctx->srp_ctx.v != NULL) &&
 175          ((s->srp_ctx.v = BN_dup(ctx->srp_ctx.v)) == NULL)) ||
 176         ((ctx->srp_ctx.b != NULL) &&
 177          ((s->srp_ctx.b = BN_dup(ctx->srp_ctx.b)) == NULL))) {
 178         SSLerr(SSL_F_SSL_SRP_CTX_INIT, ERR_R_BN_LIB);
 179         goto err;
 180     }
 181     if ((ctx->srp_ctx.login != NULL) &&
 182         ((s->srp_ctx.login = BUF_strdup(ctx->srp_ctx.login)) == NULL)) {
 183         SSLerr(SSL_F_SSL_SRP_CTX_INIT, ERR_R_INTERNAL_ERROR);
 184         goto err;
 185     }
 186     s->srp_ctx.srp_Mask = ctx->srp_ctx.srp_Mask;
 187
 188     return (1);
 189  err:
 190     OPENSSL_free(s->srp_ctx.login);
 191     BN_free(s->srp_ctx.N);
 192     BN_free(s->srp_ctx.g);
 193     BN_free(s->srp_ctx.s);
 194     BN_free(s->srp_ctx.B);
 195     BN_free(s->srp_ctx.A);
 196     BN_free(s->srp_ctx.a);
 197     BN_free(s->srp_ctx.b);
 198     BN_free(s->srp_ctx.v);
 199     return (0);
 200 }
 201
 202 int SSL_CTX_SRP_CTX_init(struct ssl_ctx_st *ctx)
 203 {
 204     if (ctx == NULL)
 205         return 0;
 206
 207     ctx->srp_ctx.SRP_cb_arg = NULL;
 208     /* set client Hello login callback */
 209     ctx->srp_ctx.TLS_ext_srp_username_callback = NULL;
 210     /* set SRP N/g param callback for verification */
 211     ctx->srp_ctx.SRP_verify_param_callback = NULL;
 212     /* set SRP client passwd callback */
 213     ctx->srp_ctx.SRP_give_srp_client_pwd_callback = NULL;
 214
 215     ctx->srp_ctx.N = NULL;
 216     ctx->srp_ctx.g = NULL;
 217     ctx->srp_ctx.s = NULL;
 218     ctx->srp_ctx.B = NULL;
 219     ctx->srp_ctx.A = NULL;
 220     ctx->srp_ctx.a = NULL;
 221     ctx->srp_ctx.b = NULL;
 222     ctx->srp_ctx.v = NULL;
 223     ctx->srp_ctx.login = NULL;
 224     ctx->srp_ctx.srp_Mask = 0;
 225     ctx->srp_ctx.info = NULL;
 226     ctx->srp_ctx.strength = SRP_MINIMAL_N;
 227
 228     return (1);
 229 }
 230
 231 /* server side */
 232 int SSL_srp_server_param_with_username(SSL *s, int *ad)
 233 {
 234     unsigned char b[SSL_MAX_MASTER_KEY_LENGTH];
 235     int al;
 236
 237     *ad = SSL_AD_UNKNOWN_PSK_IDENTITY;
 238     if ((s->srp_ctx.TLS_ext_srp_username_callback != NULL) &&
 239         ((al =
 240           s->srp_ctx.TLS_ext_srp_username_callback(s, ad,
 241                                                    s->srp_ctx.SRP_cb_arg)) !=
 242          SSL_ERROR_NONE))
 243         return al;
 244
 245     *ad = SSL_AD_INTERNAL_ERROR;
 246     if ((s->srp_ctx.N == NULL) ||
 247         (s->srp_ctx.g == NULL) ||
 248         (s->srp_ctx.s == NULL) || (s->srp_ctx.v == NULL))
 249         return SSL3_AL_FATAL;
 250
 251     if (RAND_bytes(b, sizeof(b)) <= 0)
 252         return SSL3_AL_FATAL;
 253     s->srp_ctx.b = BN_bin2bn(b, sizeof(b), NULL);
 254     OPENSSL_cleanse(b, sizeof(b));
 255
 256     /* Calculate:  B = (kv + g^b) % N  */
 257
 258     return ((s->srp_ctx.B =
 259              SRP_Calc_B(s->srp_ctx.b, s->srp_ctx.N, s->srp_ctx.g,
 260                         s->srp_ctx.v)) !=
 261             NULL) ? SSL_ERROR_NONE : SSL3_AL_FATAL;
 262 }
 263
 264 /*
 265  * If the server just has the raw password, make up a verifier entry on the
 266  * fly
 267  */
 268 int SSL_set_srp_server_param_pw(SSL *s, const char *user, const char *pass,
 269                                 const char *grp)
 270 {
 271     SRP_gN *GN = SRP_get_default_gN(grp);
 272     if (GN == NULL)
 273         return -1;
 274     s->srp_ctx.N = BN_dup(GN->N);
 275     s->srp_ctx.g = BN_dup(GN->g);
 276     BN_clear_free(s->srp_ctx.v);
 277     s->srp_ctx.v = NULL;
 278     BN_clear_free(s->srp_ctx.s);
 279     s->srp_ctx.s = NULL;
 280     if (!SRP_create_verifier_BN
 281         (user, pass, &s->srp_ctx.s, &s->srp_ctx.v, GN->N, GN->g))
 282         return -1;
 283
 284     return 1;
 285 }
 286
 287 int SSL_set_srp_server_param(SSL *s, const BIGNUM *N, const BIGNUM *g,
 288                              BIGNUM *sa, BIGNUM *v, char *info)
 289 {
 290     if (N != NULL) {
 291         if (s->srp_ctx.N != NULL) {
 292             if (!BN_copy(s->srp_ctx.N, N)) {
 293                 BN_free(s->srp_ctx.N);
 294                 s->srp_ctx.N = NULL;
 295             }
 296         } else
 297             s->srp_ctx.N = BN_dup(N);
 298     }
 299     if (g != NULL) {
 300         if (s->srp_ctx.g != NULL) {
 301             if (!BN_copy(s->srp_ctx.g, g)) {
 302                 BN_free(s->srp_ctx.g);
 303                 s->srp_ctx.g = NULL;
 304             }
 305         } else
 306             s->srp_ctx.g = BN_dup(g);
 307     }
 308     if (sa != NULL) {
 309         if (s->srp_ctx.s != NULL) {
 310             if (!BN_copy(s->srp_ctx.s, sa)) {
 311                 BN_free(s->srp_ctx.s);
 312                 s->srp_ctx.s = NULL;
 313             }
 314         } else
 315             s->srp_ctx.s = BN_dup(sa);
 316     }
 317     if (v != NULL) {
 318         if (s->srp_ctx.v != NULL) {
 319             if (!BN_copy(s->srp_ctx.v, v)) {
 320                 BN_free(s->srp_ctx.v);
 321                 s->srp_ctx.v = NULL;
 322             }
 323         } else
 324             s->srp_ctx.v = BN_dup(v);
 325     }
 326     s->srp_ctx.info = info;
 327
 328     if (!(s->srp_ctx.N) ||
 329         !(s->srp_ctx.g) || !(s->srp_ctx.s) || !(s->srp_ctx.v))
 330         return -1;
 331
 332     return 1;
 333 }
 334
 335 int srp_generate_server_master_secret(SSL *s)
 336 {
 337     BIGNUM *K = NULL, *u = NULL;
 338     int ret = -1, tmp_len = 0;
 339     unsigned char *tmp = NULL;
 340
 341     if (!SRP_Verify_A_mod_N(s->srp_ctx.A, s->srp_ctx.N))
 342         goto err;
 343     if ((u = SRP_Calc_u(s->srp_ctx.A, s->srp_ctx.B, s->srp_ctx.N)) == NULL)
 344         goto err;
 345     if ((K = SRP_Calc_server_key(s->srp_ctx.A, s->srp_ctx.v, u, s->srp_ctx.b,
 346                                  s->srp_ctx.N)) == NULL)
 347         goto err;
 348
 349     tmp_len = BN_num_bytes(K);
 350     if ((tmp = OPENSSL_malloc(tmp_len)) == NULL)
 351         goto err;
 352     BN_bn2bin(K, tmp);
 353     ret = ssl_generate_master_secret(s, tmp, tmp_len, 1);
 354  err:
 355     BN_clear_free(K);
 356     BN_clear_free(u);
 357     return ret;
 358 }
 359
 360 /* client side */
 361 int srp_generate_client_master_secret(SSL *s)
 362 {
 363     BIGNUM *x = NULL, *u = NULL, *K = NULL;
 364     int ret = -1, tmp_len = 0;
 365     char *passwd = NULL;
 366     unsigned char *tmp = NULL;
 367
 368     /*
 369      * Checks if b % n == 0
 370      */
 371     if (SRP_Verify_B_mod_N(s->srp_ctx.B, s->srp_ctx.N) == 0)
 372         goto err;
 373     if ((u = SRP_Calc_u(s->srp_ctx.A, s->srp_ctx.B, s->srp_ctx.N)) == NULL)
 374         goto err;
 375     if (s->srp_ctx.SRP_give_srp_client_pwd_callback == NULL)
 376         goto err;
 377     if (!
 378         (passwd =
 379          s->srp_ctx.SRP_give_srp_client_pwd_callback(s,
 380                                                      s->srp_ctx.SRP_cb_arg)))
 381         goto err;
 382     if ((x = SRP_Calc_x(s->srp_ctx.s, s->srp_ctx.login, passwd)) == NULL)
 383         goto err;
 384     if ((K = SRP_Calc_client_key(s->srp_ctx.N, s->srp_ctx.B, s->srp_ctx.g, x,
 385                                  s->srp_ctx.a, u)) == NULL)
 386         goto err;
 387
 388     tmp_len = BN_num_bytes(K);
 389     if ((tmp = OPENSSL_malloc(tmp_len)) == NULL)
 390         goto err;
 391     BN_bn2bin(K, tmp);
 392     ret = ssl_generate_master_secret(s, tmp, tmp_len, 1);
 393  err:
 394     BN_clear_free(K);
 395     BN_clear_free(x);
 396     OPENSSL_clear_free(passwd, strlen(passwd));
 397     BN_clear_free(u);
 398     return ret;
 399 }
 400
 401 int srp_verify_server_param(SSL *s, int *al)
 402 {
 403     SRP_CTX *srp = &s->srp_ctx;
 404     /*
 405      * Sanity check parameters: we can quickly check B % N == 0 by checking B
 406      * != 0 since B < N
 407      */
 408     if (BN_ucmp(srp->g, srp->N) >= 0 || BN_ucmp(srp->B, srp->N) >= 0
 409         || BN_is_zero(srp->B)) {
 410         *al = SSL3_AD_ILLEGAL_PARAMETER;
 411         return 0;
 412     }
 413
 414     if (BN_num_bits(srp->N) < srp->strength) {
 415         *al = TLS1_AD_INSUFFICIENT_SECURITY;
 416         return 0;
 417     }
 418
 419     if (srp->SRP_verify_param_callback) {
 420         if (srp->SRP_verify_param_callback(s, srp->SRP_cb_arg) <= 0) {
 421             *al = TLS1_AD_INSUFFICIENT_SECURITY;
 422             return 0;
 423         }
 424     } else if (!SRP_check_known_gN_param(srp->g, srp->N)) {
 425         *al = TLS1_AD_INSUFFICIENT_SECURITY;
 426         return 0;
 427     }
 428
 429     return 1;
 430 }
 431
 432 int SRP_Calc_A_param(SSL *s)
 433 {
 434     unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH];
 435
 436     if (RAND_bytes(rnd, sizeof(rnd)) <= 0)
 437         return 0;
 438     s->srp_ctx.a = BN_bin2bn(rnd, sizeof(rnd), s->srp_ctx.a);
 439     OPENSSL_cleanse(rnd, sizeof(rnd));
 440
 441     if (!
 442         (s->srp_ctx.A = SRP_Calc_A(s->srp_ctx.a, s->srp_ctx.N, s->srp_ctx.g)))
 443         return 0;
 444
 445     return 1;
 446 }
 447
 448 BIGNUM *SSL_get_srp_g(SSL *s)
 449 {
 450     if (s->srp_ctx.g != NULL)
 451         return s->srp_ctx.g;
 452     return s->ctx->srp_ctx.g;
 453 }
 454
 455 BIGNUM *SSL_get_srp_N(SSL *s)
 456 {
 457     if (s->srp_ctx.N != NULL)
 458         return s->srp_ctx.N;
 459     return s->ctx->srp_ctx.N;
 460 }
 461
 462 char *SSL_get_srp_username(SSL *s)
 463 {
 464     if (s->srp_ctx.login != NULL)
 465         return s->srp_ctx.login;
 466     return s->ctx->srp_ctx.login;
 467 }
 468
 469 char *SSL_get_srp_userinfo(SSL *s)
 470 {
 471     if (s->srp_ctx.info != NULL)
 472         return s->srp_ctx.info;
 473     return s->ctx->srp_ctx.info;
 474 }
 475
 476 # define tls1_ctx_ctrl ssl3_ctx_ctrl
 477 # define tls1_ctx_callback_ctrl ssl3_ctx_callback_ctrl
 478
 479 int SSL_CTX_set_srp_username(SSL_CTX *ctx, char *name)
 480 {
 481     return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_USERNAME, 0, name);
 482 }
 483
 484 int SSL_CTX_set_srp_password(SSL_CTX *ctx, char *password)
 485 {
 486     return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_PASSWORD, 0, password);
 487 }
 488
 489 int SSL_CTX_set_srp_strength(SSL_CTX *ctx, int strength)
 490 {
 491     return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_STRENGTH, strength,
 492                          NULL);
 493 }
 494
 495 int SSL_CTX_set_srp_verify_param_callback(SSL_CTX *ctx,
 496                                           int (*cb) (SSL *, void *))
 497 {
 498     return tls1_ctx_callback_ctrl(ctx, SSL_CTRL_SET_SRP_VERIFY_PARAM_CB,
 499                                   (void (*)(void))cb);
 500 }
 501
 502 int SSL_CTX_set_srp_cb_arg(SSL_CTX *ctx, void *arg)
 503 {
 504     return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_SRP_ARG, 0, arg);
 505 }
 506
 507 int SSL_CTX_set_srp_username_callback(SSL_CTX *ctx,
 508                                       int (*cb) (SSL *, int *, void *))
 509 {
 510     return tls1_ctx_callback_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_USERNAME_CB,
 511                                   (void (*)(void))cb);
 512 }
 513
 514 int SSL_CTX_set_srp_client_pwd_callback(SSL_CTX *ctx,
 515                                         char *(*cb) (SSL *, void *))
 516 {
 517     return tls1_ctx_callback_ctrl(ctx, SSL_CTRL_SET_SRP_GIVE_CLIENT_PWD_CB,
 518                                   (void (*)(void))cb);
 519 }
 520
 521 #endif