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 #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