crypto/openssl/crypto/srp/srp_vfy.c

   1 /* crypto/srp/srp_vfy.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 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 #ifndef OPENSSL_NO_SRP
  61 # include "cryptlib.h"
  62 # include "srp_lcl.h"
  63 # include <openssl/srp.h>
  64 # include <openssl/evp.h>
  65 # include <openssl/buffer.h>
  66 # include <openssl/rand.h>
  67 # include <openssl/txt_db.h>
  68
  69 # define SRP_RANDOM_SALT_LEN 20
  70 # define MAX_LEN 2500
  71
  72 static char b64table[] =
  73     "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz./";
  74
  75 /*
  76  * the following two conversion routines have been inspired by code from
  77  * Stanford
  78  */
  79
  80 /*
  81  * Convert a base64 string into raw byte array representation.
  82  */
  83 static int t_fromb64(unsigned char *a, const char *src)
  84 {
  85     char *loc;
  86     int i, j;
  87     int size;
  88
  89     while (*src && (*src == ' ' || *src == '\t' || *src == '\n'))
  90         ++src;
  91     size = strlen(src);
  92     i = 0;
  93     while (i < size) {
  94         loc = strchr(b64table, src[i]);
  95         if (loc == (char *)0)
  96             break;
  97         else
  98             a[i] = loc - b64table;
  99         ++i;
 100     }
 101     /* if nothing valid to process we have a zero length response */
 102     if (i == 0)
 103         return 0;
 104     size = i;
 105     i = size - 1;
 106     j = size;
 107     while (1) {
 108         a[j] = a[i];
 109         if (--i < 0)
 110             break;
 111         a[j] |= (a[i] & 3) << 6;
 112         --j;
 113         a[j] = (unsigned char)((a[i] & 0x3c) >> 2);
 114         if (--i < 0)
 115             break;
 116         a[j] |= (a[i] & 0xf) << 4;
 117         --j;
 118         a[j] = (unsigned char)((a[i] & 0x30) >> 4);
 119         if (--i < 0)
 120             break;
 121         a[j] |= (a[i] << 2);
 122
 123         a[--j] = 0;
 124         if (--i < 0)
 125             break;
 126     }
 127     while (a[j] == 0 && j <= size)
 128         ++j;
 129     i = 0;
 130     while (j <= size)
 131         a[i++] = a[j++];
 132     return i;
 133 }
 134
 135 /*
 136  * Convert a raw byte string into a null-terminated base64 ASCII string.
 137  */
 138 static char *t_tob64(char *dst, const unsigned char *src, int size)
 139 {
 140     int c, pos = size % 3;
 141     unsigned char b0 = 0, b1 = 0, b2 = 0, notleading = 0;
 142     char *olddst = dst;
 143
 144     switch (pos) {
 145     case 1:
 146         b2 = src[0];
 147         break;
 148     case 2:
 149         b1 = src[0];
 150         b2 = src[1];
 151         break;
 152     }
 153
 154     while (1) {
 155         c = (b0 & 0xfc) >> 2;
 156         if (notleading || c != 0) {
 157             *dst++ = b64table[c];
 158             notleading = 1;
 159         }
 160         c = ((b0 & 3) << 4) | ((b1 & 0xf0) >> 4);
 161         if (notleading || c != 0) {
 162             *dst++ = b64table[c];
 163             notleading = 1;
 164         }
 165         c = ((b1 & 0xf) << 2) | ((b2 & 0xc0) >> 6);
 166         if (notleading || c != 0) {
 167             *dst++ = b64table[c];
 168             notleading = 1;
 169         }
 170         c = b2 & 0x3f;
 171         if (notleading || c != 0) {
 172             *dst++ = b64table[c];
 173             notleading = 1;
 174         }
 175         if (pos >= size)
 176             break;
 177         else {
 178             b0 = src[pos++];
 179             b1 = src[pos++];
 180             b2 = src[pos++];
 181         }
 182     }
 183
 184     *dst++ = '\0';
 185     return olddst;
 186 }
 187
 188 void SRP_user_pwd_free(SRP_user_pwd *user_pwd)
 189 {
 190     if (user_pwd == NULL)
 191         return;
 192     BN_free(user_pwd->s);
 193     BN_clear_free(user_pwd->v);
 194     OPENSSL_free(user_pwd->id);
 195     OPENSSL_free(user_pwd->info);
 196     OPENSSL_free(user_pwd);
 197 }
 198
 199 static SRP_user_pwd *SRP_user_pwd_new()
 200 {
 201     SRP_user_pwd *ret = OPENSSL_malloc(sizeof(SRP_user_pwd));
 202     if (ret == NULL)
 203         return NULL;
 204     ret->N = NULL;
 205     ret->g = NULL;
 206     ret->s = NULL;
 207     ret->v = NULL;
 208     ret->id = NULL;
 209     ret->info = NULL;
 210     return ret;
 211 }
 212
 213 static void SRP_user_pwd_set_gN(SRP_user_pwd *vinfo, const BIGNUM *g,
 214                                 const BIGNUM *N)
 215 {
 216     vinfo->N = N;
 217     vinfo->g = g;
 218 }
 219
 220 static int SRP_user_pwd_set_ids(SRP_user_pwd *vinfo, const char *id,
 221                                 const char *info)
 222 {
 223     if (id != NULL && NULL == (vinfo->id = BUF_strdup(id)))
 224         return 0;
 225     return (info == NULL || NULL != (vinfo->info = BUF_strdup(info)));
 226 }
 227
 228 static int SRP_user_pwd_set_sv(SRP_user_pwd *vinfo, const char *s,
 229                                const char *v)
 230 {
 231     unsigned char tmp[MAX_LEN];
 232     int len;
 233
 234     if (strlen(s) > MAX_LEN || strlen(v) > MAX_LEN)
 235         return 0;
 236     len = t_fromb64(tmp, v);
 237     if (NULL == (vinfo->v = BN_bin2bn(tmp, len, NULL)))
 238         return 0;
 239     len = t_fromb64(tmp, s);
 240     return ((vinfo->s = BN_bin2bn(tmp, len, NULL)) != NULL);
 241 }
 242
 243 static int SRP_user_pwd_set_sv_BN(SRP_user_pwd *vinfo, BIGNUM *s, BIGNUM *v)
 244 {
 245     vinfo->v = v;
 246     vinfo->s = s;
 247     return (vinfo->s != NULL && vinfo->v != NULL);
 248 }
 249
 250 static SRP_user_pwd *srp_user_pwd_dup(SRP_user_pwd *src)
 251 {
 252     SRP_user_pwd *ret;
 253
 254     if (src == NULL)
 255         return NULL;
 256     if ((ret = SRP_user_pwd_new()) == NULL)
 257         return NULL;
 258
 259     SRP_user_pwd_set_gN(ret, src->g, src->N);
 260     if (!SRP_user_pwd_set_ids(ret, src->id, src->info)
 261         || !SRP_user_pwd_set_sv_BN(ret, BN_dup(src->s), BN_dup(src->v))) {
 262             SRP_user_pwd_free(ret);
 263             return NULL;
 264     }
 265     return ret;
 266 }
 267
 268 SRP_VBASE *SRP_VBASE_new(char *seed_key)
 269 {
 270     SRP_VBASE *vb = (SRP_VBASE *)OPENSSL_malloc(sizeof(SRP_VBASE));
 271
 272     if (vb == NULL)
 273         return NULL;
 274     if (!(vb->users_pwd = sk_SRP_user_pwd_new_null()) ||
 275         !(vb->gN_cache = sk_SRP_gN_cache_new_null())) {
 276         OPENSSL_free(vb);
 277         return NULL;
 278     }
 279     vb->default_g = NULL;
 280     vb->default_N = NULL;
 281     vb->seed_key = NULL;
 282     if ((seed_key != NULL) && (vb->seed_key = BUF_strdup(seed_key)) == NULL) {
 283         sk_SRP_user_pwd_free(vb->users_pwd);
 284         sk_SRP_gN_cache_free(vb->gN_cache);
 285         OPENSSL_free(vb);
 286         return NULL;
 287     }
 288     return vb;
 289 }
 290
 291 int SRP_VBASE_free(SRP_VBASE *vb)
 292 {
 293     sk_SRP_user_pwd_pop_free(vb->users_pwd, SRP_user_pwd_free);
 294     sk_SRP_gN_cache_free(vb->gN_cache);
 295     OPENSSL_free(vb->seed_key);
 296     OPENSSL_free(vb);
 297     return 0;
 298 }
 299
 300 static SRP_gN_cache *SRP_gN_new_init(const char *ch)
 301 {
 302     unsigned char tmp[MAX_LEN];
 303     int len;
 304
 305     SRP_gN_cache *newgN =
 306         (SRP_gN_cache *)OPENSSL_malloc(sizeof(SRP_gN_cache));
 307     if (newgN == NULL)
 308         return NULL;
 309
 310     if ((newgN->b64_bn = BUF_strdup(ch)) == NULL)
 311         goto err;
 312
 313     len = t_fromb64(tmp, ch);
 314     if ((newgN->bn = BN_bin2bn(tmp, len, NULL)))
 315         return newgN;
 316
 317     OPENSSL_free(newgN->b64_bn);
 318  err:
 319     OPENSSL_free(newgN);
 320     return NULL;
 321 }
 322
 323 static void SRP_gN_free(SRP_gN_cache *gN_cache)
 324 {
 325     if (gN_cache == NULL)
 326         return;
 327     OPENSSL_free(gN_cache->b64_bn);
 328     BN_free(gN_cache->bn);
 329     OPENSSL_free(gN_cache);
 330 }
 331
 332 static SRP_gN *SRP_get_gN_by_id(const char *id, STACK_OF(SRP_gN) *gN_tab)
 333 {
 334     int i;
 335
 336     SRP_gN *gN;
 337     if (gN_tab != NULL)
 338         for (i = 0; i < sk_SRP_gN_num(gN_tab); i++) {
 339             gN = sk_SRP_gN_value(gN_tab, i);
 340             if (gN && (id == NULL || strcmp(gN->id, id) == 0))
 341                 return gN;
 342         }
 343
 344     return SRP_get_default_gN(id);
 345 }
 346
 347 static BIGNUM *SRP_gN_place_bn(STACK_OF(SRP_gN_cache) *gN_cache, char *ch)
 348 {
 349     int i;
 350     if (gN_cache == NULL)
 351         return NULL;
 352
 353     /* search if we have already one... */
 354     for (i = 0; i < sk_SRP_gN_cache_num(gN_cache); i++) {
 355         SRP_gN_cache *cache = sk_SRP_gN_cache_value(gN_cache, i);
 356         if (strcmp(cache->b64_bn, ch) == 0)
 357             return cache->bn;
 358     }
 359     {                           /* it is the first time that we find it */
 360         SRP_gN_cache *newgN = SRP_gN_new_init(ch);
 361         if (newgN) {
 362             if (sk_SRP_gN_cache_insert(gN_cache, newgN, 0) > 0)
 363                 return newgN->bn;
 364             SRP_gN_free(newgN);
 365         }
 366     }
 367     return NULL;
 368 }
 369
 370 /*
 371  * this function parses verifier file. Format is:
 372  * string(index):base64(N):base64(g):0
 373  * string(username):base64(v):base64(salt):int(index)
 374  */
 375
 376 int SRP_VBASE_init(SRP_VBASE *vb, char *verifier_file)
 377 {
 378     int error_code;
 379     STACK_OF(SRP_gN) *SRP_gN_tab = sk_SRP_gN_new_null();
 380     char *last_index = NULL;
 381     int i;
 382     char **pp;
 383
 384     SRP_gN *gN = NULL;
 385     SRP_user_pwd *user_pwd = NULL;
 386
 387     TXT_DB *tmpdb = NULL;
 388     BIO *in = BIO_new(BIO_s_file());
 389
 390     error_code = SRP_ERR_OPEN_FILE;
 391
 392     if (in == NULL || BIO_read_filename(in, verifier_file) <= 0)
 393         goto err;
 394
 395     error_code = SRP_ERR_VBASE_INCOMPLETE_FILE;
 396
 397     if ((tmpdb = TXT_DB_read(in, DB_NUMBER)) == NULL)
 398         goto err;
 399
 400     error_code = SRP_ERR_MEMORY;
 401
 402     if (vb->seed_key) {
 403         last_index = SRP_get_default_gN(NULL)->id;
 404     }
 405     for (i = 0; i < sk_OPENSSL_PSTRING_num(tmpdb->data); i++) {
 406         pp = sk_OPENSSL_PSTRING_value(tmpdb->data, i);
 407         if (pp[DB_srptype][0] == DB_SRP_INDEX) {
 408             /*
 409              * we add this couple in the internal Stack
 410              */
 411
 412             if ((gN = (SRP_gN *) OPENSSL_malloc(sizeof(SRP_gN))) == NULL)
 413                 goto err;
 414
 415             if (!(gN->id = BUF_strdup(pp[DB_srpid]))
 416                 || !(gN->N =
 417                      SRP_gN_place_bn(vb->gN_cache, pp[DB_srpverifier]))
 418                 || !(gN->g = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpsalt]))
 419                 || sk_SRP_gN_insert(SRP_gN_tab, gN, 0) == 0)
 420                 goto err;
 421
 422             gN = NULL;
 423
 424             if (vb->seed_key != NULL) {
 425                 last_index = pp[DB_srpid];
 426             }
 427         } else if (pp[DB_srptype][0] == DB_SRP_VALID) {
 428             /* it is a user .... */
 429             SRP_gN *lgN;
 430             if ((lgN = SRP_get_gN_by_id(pp[DB_srpgN], SRP_gN_tab)) != NULL) {
 431                 error_code = SRP_ERR_MEMORY;
 432                 if ((user_pwd = SRP_user_pwd_new()) == NULL)
 433                     goto err;
 434
 435                 SRP_user_pwd_set_gN(user_pwd, lgN->g, lgN->N);
 436                 if (!SRP_user_pwd_set_ids
 437                     (user_pwd, pp[DB_srpid], pp[DB_srpinfo]))
 438                     goto err;
 439
 440                 error_code = SRP_ERR_VBASE_BN_LIB;
 441                 if (!SRP_user_pwd_set_sv
 442                     (user_pwd, pp[DB_srpsalt], pp[DB_srpverifier]))
 443                     goto err;
 444
 445                 if (sk_SRP_user_pwd_insert(vb->users_pwd, user_pwd, 0) == 0)
 446                     goto err;
 447                 user_pwd = NULL; /* abandon responsability */
 448             }
 449         }
 450     }
 451
 452     if (last_index != NULL) {
 453         /* this means that we want to simulate a default user */
 454
 455         if (((gN = SRP_get_gN_by_id(last_index, SRP_gN_tab)) == NULL)) {
 456             error_code = SRP_ERR_VBASE_BN_LIB;
 457             goto err;
 458         }
 459         vb->default_g = gN->g;
 460         vb->default_N = gN->N;
 461         gN = NULL;
 462     }
 463     error_code = SRP_NO_ERROR;
 464
 465  err:
 466     /*
 467      * there may be still some leaks to fix, if this fails, the application
 468      * terminates most likely
 469      */
 470
 471     if (gN != NULL) {
 472         OPENSSL_free(gN->id);
 473         OPENSSL_free(gN);
 474     }
 475
 476     SRP_user_pwd_free(user_pwd);
 477
 478     if (tmpdb)
 479         TXT_DB_free(tmpdb);
 480     if (in)
 481         BIO_free_all(in);
 482
 483     sk_SRP_gN_free(SRP_gN_tab);
 484
 485     return error_code;
 486
 487 }
 488
 489 static SRP_user_pwd *find_user(SRP_VBASE *vb, char *username)
 490 {
 491     int i;
 492     SRP_user_pwd *user;
 493
 494     if (vb == NULL)
 495         return NULL;
 496
 497     for (i = 0; i < sk_SRP_user_pwd_num(vb->users_pwd); i++) {
 498         user = sk_SRP_user_pwd_value(vb->users_pwd, i);
 499         if (strcmp(user->id, username) == 0)
 500             return user;
 501     }
 502
 503     return NULL;
 504 }
 505
 506 /*
 507  * This method ignores the configured seed and fails for an unknown user.
 508  * Ownership of the returned pointer is not released to the caller.
 509  * In other words, caller must not free the result.
 510  */
 511 SRP_user_pwd *SRP_VBASE_get_by_user(SRP_VBASE *vb, char *username)
 512 {
 513     return find_user(vb, username);
 514 }
 515
 516 /*
 517  * Ownership of the returned pointer is released to the caller.
 518  * In other words, caller must free the result once done.
 519  */
 520 SRP_user_pwd *SRP_VBASE_get1_by_user(SRP_VBASE *vb, char *username)
 521 {
 522     SRP_user_pwd *user;
 523     unsigned char digv[SHA_DIGEST_LENGTH];
 524     unsigned char digs[SHA_DIGEST_LENGTH];
 525     EVP_MD_CTX ctxt;
 526
 527     if (vb == NULL)
 528         return NULL;
 529
 530     if ((user = find_user(vb, username)) != NULL)
 531         return srp_user_pwd_dup(user);
 532
 533     if ((vb->seed_key == NULL) ||
 534         (vb->default_g == NULL) || (vb->default_N == NULL))
 535         return NULL;
 536
 537 /* if the user is unknown we set parameters as well if we have a seed_key */
 538
 539     if ((user = SRP_user_pwd_new()) == NULL)
 540         return NULL;
 541
 542     SRP_user_pwd_set_gN(user, vb->default_g, vb->default_N);
 543
 544     if (!SRP_user_pwd_set_ids(user, username, NULL))
 545         goto err;
 546
 547     if (RAND_pseudo_bytes(digv, SHA_DIGEST_LENGTH) < 0)
 548         goto err;
 549     EVP_MD_CTX_init(&ctxt);
 550     EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
 551     EVP_DigestUpdate(&ctxt, vb->seed_key, strlen(vb->seed_key));
 552     EVP_DigestUpdate(&ctxt, username, strlen(username));
 553     EVP_DigestFinal_ex(&ctxt, digs, NULL);
 554     EVP_MD_CTX_cleanup(&ctxt);
 555     if (SRP_user_pwd_set_sv_BN
 556         (user, BN_bin2bn(digs, SHA_DIGEST_LENGTH, NULL),
 557          BN_bin2bn(digv, SHA_DIGEST_LENGTH, NULL)))
 558         return user;
 559
 560  err:SRP_user_pwd_free(user);
 561     return NULL;
 562 }
 563
 564 /*
 565  * create a verifier (*salt,*verifier,g and N are in base64)
 566  */
 567 char *SRP_create_verifier(const char *user, const char *pass, char **salt,
 568                           char **verifier, const char *N, const char *g)
 569 {
 570     int len;
 571     char *result = NULL, *vf = NULL;
 572     BIGNUM *N_bn = NULL, *g_bn = NULL, *s = NULL, *v = NULL;
 573     unsigned char tmp[MAX_LEN];
 574     unsigned char tmp2[MAX_LEN];
 575     char *defgNid = NULL;
 576     int vfsize = 0;
 577
 578     if ((user == NULL) ||
 579         (pass == NULL) || (salt == NULL) || (verifier == NULL))
 580         goto err;
 581
 582     if (N) {
 583         if (!(len = t_fromb64(tmp, N)))
 584             goto err;
 585         N_bn = BN_bin2bn(tmp, len, NULL);
 586         if (!(len = t_fromb64(tmp, g)))
 587             goto err;
 588         g_bn = BN_bin2bn(tmp, len, NULL);
 589         defgNid = "*";
 590     } else {
 591         SRP_gN *gN = SRP_get_gN_by_id(g, NULL);
 592         if (gN == NULL)
 593             goto err;
 594         N_bn = gN->N;
 595         g_bn = gN->g;
 596         defgNid = gN->id;
 597     }
 598
 599     if (*salt == NULL) {
 600         if (RAND_pseudo_bytes(tmp2, SRP_RANDOM_SALT_LEN) < 0)
 601             goto err;
 602
 603         s = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
 604     } else {
 605         if (!(len = t_fromb64(tmp2, *salt)))
 606             goto err;
 607         s = BN_bin2bn(tmp2, len, NULL);
 608     }
 609
 610     if (!SRP_create_verifier_BN(user, pass, &s, &v, N_bn, g_bn))
 611         goto err;
 612
 613     BN_bn2bin(v, tmp);
 614     vfsize = BN_num_bytes(v) * 2;
 615     if (((vf = OPENSSL_malloc(vfsize)) == NULL))
 616         goto err;
 617     t_tob64(vf, tmp, BN_num_bytes(v));
 618
 619     if (*salt == NULL) {
 620         char *tmp_salt;
 621
 622         if ((tmp_salt = OPENSSL_malloc(SRP_RANDOM_SALT_LEN * 2)) == NULL) {
 623             goto err;
 624         }
 625         t_tob64(tmp_salt, tmp2, SRP_RANDOM_SALT_LEN);
 626         *salt = tmp_salt;
 627     }
 628
 629     *verifier = vf;
 630     vf = NULL;
 631     result = defgNid;
 632
 633  err:
 634     if (N) {
 635         BN_free(N_bn);
 636         BN_free(g_bn);
 637     }
 638     OPENSSL_cleanse(vf, vfsize);
 639     OPENSSL_free(vf);
 640     BN_clear_free(s);
 641     BN_clear_free(v);
 642     return result;
 643 }
 644
 645 /*
 646  * create a verifier (*salt,*verifier,g and N are BIGNUMs). If *salt != NULL
 647  * then the provided salt will be used. On successful exit *verifier will point
 648  * to a newly allocated BIGNUM containing the verifier and (if a salt was not
 649  * provided) *salt will be populated with a newly allocated BIGNUM containing a
 650  * random salt.
 651  * The caller is responsible for freeing the allocated *salt and *verifier
 652  * BIGNUMS.
 653  */
 654 int SRP_create_verifier_BN(const char *user, const char *pass, BIGNUM **salt,
 655                            BIGNUM **verifier, BIGNUM *N, BIGNUM *g)
 656 {
 657     int result = 0;
 658     BIGNUM *x = NULL;
 659     BN_CTX *bn_ctx = BN_CTX_new();
 660     unsigned char tmp2[MAX_LEN];
 661     BIGNUM *salttmp = NULL;
 662
 663     if ((user == NULL) ||
 664         (pass == NULL) ||
 665         (salt == NULL) ||
 666         (verifier == NULL) || (N == NULL) || (g == NULL) || (bn_ctx == NULL))
 667         goto err;
 668
 669     srp_bn_print(N);
 670     srp_bn_print(g);
 671
 672     if (*salt == NULL) {
 673         if (RAND_pseudo_bytes(tmp2, SRP_RANDOM_SALT_LEN) < 0)
 674             goto err;
 675
 676         salttmp = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
 677     } else {
 678         salttmp = *salt;
 679     }
 680
 681     x = SRP_Calc_x(salttmp, user, pass);
 682
 683     *verifier = BN_new();
 684     if (*verifier == NULL)
 685         goto err;
 686
 687     if (!BN_mod_exp(*verifier, g, x, N, bn_ctx)) {
 688         BN_clear_free(*verifier);
 689         goto err;
 690     }
 691
 692     srp_bn_print(*verifier);
 693
 694     result = 1;
 695     *salt = salttmp;
 696
 697  err:
 698     if (*salt != salttmp)
 699         BN_clear_free(salttmp);
 700     BN_clear_free(x);
 701     BN_CTX_free(bn_ctx);
 702     return result;
 703 }
 704
 705 #endif