srp_vfy.c revision 325335 
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
72static 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 */
83static int t_fromb64(unsigned char *a, size_t alen, const char *src)
84{
85    char *loc;
86    int i, j;
87    int size;
88
89    if (alen == 0 || alen > INT_MAX)
90        return -1;
91
92    while (*src && (*src == ' ' || *src == '\t' || *src == '\n'))
93        ++src;
94    size = strlen(src);
95    if (size < 0 || size >= (int)alen)
96        return -1;
97
98    i = 0;
99    while (i < size) {
100        loc = strchr(b64table, src[i]);
101        if (loc == (char *)0)
102            break;
103        else
104            a[i] = loc - b64table;
105        ++i;
106    }
107    /* if nothing valid to process we have a zero length response */
108    if (i == 0)
109        return 0;
110    size = i;
111    i = size - 1;
112    j = size;
113    while (1) {
114        a[j] = a[i];
115        if (--i < 0)
116            break;
117        a[j] |= (a[i] & 3) << 6;
118        --j;
119        a[j] = (unsigned char)((a[i] & 0x3c) >> 2);
120        if (--i < 0)
121            break;
122        a[j] |= (a[i] & 0xf) << 4;
123        --j;
124        a[j] = (unsigned char)((a[i] & 0x30) >> 4);
125        if (--i < 0)
126            break;
127        a[j] |= (a[i] << 2);
128
129        a[--j] = 0;
130        if (--i < 0)
131            break;
132    }
133    while (j <= size && a[j] == 0)
134        ++j;
135    i = 0;
136    while (j <= size)
137        a[i++] = a[j++];
138    return i;
139}
140
141/*
142 * Convert a raw byte string into a null-terminated base64 ASCII string.
143 */
144static char *t_tob64(char *dst, const unsigned char *src, int size)
145{
146    int c, pos = size % 3;
147    unsigned char b0 = 0, b1 = 0, b2 = 0, notleading = 0;
148    char *olddst = dst;
149
150    switch (pos) {
151    case 1:
152        b2 = src[0];
153        break;
154    case 2:
155        b1 = src[0];
156        b2 = src[1];
157        break;
158    }
159
160    while (1) {
161        c = (b0 & 0xfc) >> 2;
162        if (notleading || c != 0) {
163            *dst++ = b64table[c];
164            notleading = 1;
165        }
166        c = ((b0 & 3) << 4) | ((b1 & 0xf0) >> 4);
167        if (notleading || c != 0) {
168            *dst++ = b64table[c];
169            notleading = 1;
170        }
171        c = ((b1 & 0xf) << 2) | ((b2 & 0xc0) >> 6);
172        if (notleading || c != 0) {
173            *dst++ = b64table[c];
174            notleading = 1;
175        }
176        c = b2 & 0x3f;
177        if (notleading || c != 0) {
178            *dst++ = b64table[c];
179            notleading = 1;
180        }
181        if (pos >= size)
182            break;
183        else {
184            b0 = src[pos++];
185            b1 = src[pos++];
186            b2 = src[pos++];
187        }
188    }
189
190    *dst++ = '\0';
191    return olddst;
192}
193
194void SRP_user_pwd_free(SRP_user_pwd *user_pwd)
195{
196    if (user_pwd == NULL)
197        return;
198    BN_free(user_pwd->s);
199    BN_clear_free(user_pwd->v);
200    OPENSSL_free(user_pwd->id);
201    OPENSSL_free(user_pwd->info);
202    OPENSSL_free(user_pwd);
203}
204
205static SRP_user_pwd *SRP_user_pwd_new()
206{
207    SRP_user_pwd *ret = OPENSSL_malloc(sizeof(SRP_user_pwd));
208    if (ret == NULL)
209        return NULL;
210    ret->N = NULL;
211    ret->g = NULL;
212    ret->s = NULL;
213    ret->v = NULL;
214    ret->id = NULL;
215    ret->info = NULL;
216    return ret;
217}
218
219static void SRP_user_pwd_set_gN(SRP_user_pwd *vinfo, const BIGNUM *g,
220                                const BIGNUM *N)
221{
222    vinfo->N = N;
223    vinfo->g = g;
224}
225
226static int SRP_user_pwd_set_ids(SRP_user_pwd *vinfo, const char *id,
227                                const char *info)
228{
229    if (id != NULL && NULL == (vinfo->id = BUF_strdup(id)))
230        return 0;
231    return (info == NULL || NULL != (vinfo->info = BUF_strdup(info)));
232}
233
234static int SRP_user_pwd_set_sv(SRP_user_pwd *vinfo, const char *s,
235                               const char *v)
236{
237    unsigned char tmp[MAX_LEN];
238    int len;
239
240    vinfo->v = NULL;
241    vinfo->s = NULL;
242
243    len = t_fromb64(tmp, sizeof(tmp), v);
244    if (len < 0)
245        return 0;
246    if (NULL == (vinfo->v = BN_bin2bn(tmp, len, NULL)))
247        return 0;
248    len = t_fromb64(tmp, sizeof(tmp), s);
249    if (len < 0)
250        goto err;
251    vinfo->s = BN_bin2bn(tmp, len, NULL);
252    if (vinfo->s == NULL)
253        goto err;
254    return 1;
255 err:
256    BN_free(vinfo->v);
257    vinfo->v = NULL;
258    return 0;
259}
260
261static int SRP_user_pwd_set_sv_BN(SRP_user_pwd *vinfo, BIGNUM *s, BIGNUM *v)
262{
263    vinfo->v = v;
264    vinfo->s = s;
265    return (vinfo->s != NULL && vinfo->v != NULL);
266}
267
268static SRP_user_pwd *srp_user_pwd_dup(SRP_user_pwd *src)
269{
270    SRP_user_pwd *ret;
271
272    if (src == NULL)
273        return NULL;
274    if ((ret = SRP_user_pwd_new()) == NULL)
275        return NULL;
276
277    SRP_user_pwd_set_gN(ret, src->g, src->N);
278    if (!SRP_user_pwd_set_ids(ret, src->id, src->info)
279        || !SRP_user_pwd_set_sv_BN(ret, BN_dup(src->s), BN_dup(src->v))) {
280            SRP_user_pwd_free(ret);
281            return NULL;
282    }
283    return ret;
284}
285
286SRP_VBASE *SRP_VBASE_new(char *seed_key)
287{
288    SRP_VBASE *vb = (SRP_VBASE *)OPENSSL_malloc(sizeof(SRP_VBASE));
289
290    if (vb == NULL)
291        return NULL;
292    if (!(vb->users_pwd = sk_SRP_user_pwd_new_null()) ||
293        !(vb->gN_cache = sk_SRP_gN_cache_new_null())) {
294        OPENSSL_free(vb);
295        return NULL;
296    }
297    vb->default_g = NULL;
298    vb->default_N = NULL;
299    vb->seed_key = NULL;
300    if ((seed_key != NULL) && (vb->seed_key = BUF_strdup(seed_key)) == NULL) {
301        sk_SRP_user_pwd_free(vb->users_pwd);
302        sk_SRP_gN_cache_free(vb->gN_cache);
303        OPENSSL_free(vb);
304        return NULL;
305    }
306    return vb;
307}
308
309int SRP_VBASE_free(SRP_VBASE *vb)
310{
311    sk_SRP_user_pwd_pop_free(vb->users_pwd, SRP_user_pwd_free);
312    sk_SRP_gN_cache_free(vb->gN_cache);
313    OPENSSL_free(vb->seed_key);
314    OPENSSL_free(vb);
315    return 0;
316}
317
318static SRP_gN_cache *SRP_gN_new_init(const char *ch)
319{
320    unsigned char tmp[MAX_LEN];
321    int len;
322
323    SRP_gN_cache *newgN =
324        (SRP_gN_cache *)OPENSSL_malloc(sizeof(SRP_gN_cache));
325    if (newgN == NULL)
326        return NULL;
327
328    len = t_fromb64(tmp, sizeof(tmp), ch);
329    if (len < 0)
330        goto err;
331
332    if ((newgN->b64_bn = BUF_strdup(ch)) == NULL)
333        goto err;
334
335    if ((newgN->bn = BN_bin2bn(tmp, len, NULL)))
336        return newgN;
337
338    OPENSSL_free(newgN->b64_bn);
339 err:
340    OPENSSL_free(newgN);
341    return NULL;
342}
343
344static void SRP_gN_free(SRP_gN_cache *gN_cache)
345{
346    if (gN_cache == NULL)
347        return;
348    OPENSSL_free(gN_cache->b64_bn);
349    BN_free(gN_cache->bn);
350    OPENSSL_free(gN_cache);
351}
352
353static SRP_gN *SRP_get_gN_by_id(const char *id, STACK_OF(SRP_gN) *gN_tab)
354{
355    int i;
356
357    SRP_gN *gN;
358    if (gN_tab != NULL)
359        for (i = 0; i < sk_SRP_gN_num(gN_tab); i++) {
360            gN = sk_SRP_gN_value(gN_tab, i);
361            if (gN && (id == NULL || strcmp(gN->id, id) == 0))
362                return gN;
363        }
364
365    return SRP_get_default_gN(id);
366}
367
368static BIGNUM *SRP_gN_place_bn(STACK_OF(SRP_gN_cache) *gN_cache, char *ch)
369{
370    int i;
371    if (gN_cache == NULL)
372        return NULL;
373
374    /* search if we have already one... */
375    for (i = 0; i < sk_SRP_gN_cache_num(gN_cache); i++) {
376        SRP_gN_cache *cache = sk_SRP_gN_cache_value(gN_cache, i);
377        if (strcmp(cache->b64_bn, ch) == 0)
378            return cache->bn;
379    }
380    {                           /* it is the first time that we find it */
381        SRP_gN_cache *newgN = SRP_gN_new_init(ch);
382        if (newgN) {
383            if (sk_SRP_gN_cache_insert(gN_cache, newgN, 0) > 0)
384                return newgN->bn;
385            SRP_gN_free(newgN);
386        }
387    }
388    return NULL;
389}
390
391/*
392 * this function parses verifier file. Format is:
393 * string(index):base64(N):base64(g):0
394 * string(username):base64(v):base64(salt):int(index)
395 */
396
397int SRP_VBASE_init(SRP_VBASE *vb, char *verifier_file)
398{
399    int error_code;
400    STACK_OF(SRP_gN) *SRP_gN_tab = sk_SRP_gN_new_null();
401    char *last_index = NULL;
402    int i;
403    char **pp;
404
405    SRP_gN *gN = NULL;
406    SRP_user_pwd *user_pwd = NULL;
407
408    TXT_DB *tmpdb = NULL;
409    BIO *in = BIO_new(BIO_s_file());
410
411    error_code = SRP_ERR_OPEN_FILE;
412
413    if (in == NULL || BIO_read_filename(in, verifier_file) <= 0)
414        goto err;
415
416    error_code = SRP_ERR_VBASE_INCOMPLETE_FILE;
417
418    if ((tmpdb = TXT_DB_read(in, DB_NUMBER)) == NULL)
419        goto err;
420
421    error_code = SRP_ERR_MEMORY;
422
423    if (vb->seed_key) {
424        last_index = SRP_get_default_gN(NULL)->id;
425    }
426    for (i = 0; i < sk_OPENSSL_PSTRING_num(tmpdb->data); i++) {
427        pp = sk_OPENSSL_PSTRING_value(tmpdb->data, i);
428        if (pp[DB_srptype][0] == DB_SRP_INDEX) {
429            /*
430             * we add this couple in the internal Stack
431             */
432
433            if ((gN = (SRP_gN *) OPENSSL_malloc(sizeof(SRP_gN))) == NULL)
434                goto err;
435
436            if (!(gN->id = BUF_strdup(pp[DB_srpid]))
437                || !(gN->N =
438                     SRP_gN_place_bn(vb->gN_cache, pp[DB_srpverifier]))
439                || !(gN->g = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpsalt]))
440                || sk_SRP_gN_insert(SRP_gN_tab, gN, 0) == 0)
441                goto err;
442
443            gN = NULL;
444
445            if (vb->seed_key != NULL) {
446                last_index = pp[DB_srpid];
447            }
448        } else if (pp[DB_srptype][0] == DB_SRP_VALID) {
449            /* it is a user .... */
450            SRP_gN *lgN;
451            if ((lgN = SRP_get_gN_by_id(pp[DB_srpgN], SRP_gN_tab)) != NULL) {
452                error_code = SRP_ERR_MEMORY;
453                if ((user_pwd = SRP_user_pwd_new()) == NULL)
454                    goto err;
455
456                SRP_user_pwd_set_gN(user_pwd, lgN->g, lgN->N);
457                if (!SRP_user_pwd_set_ids
458                    (user_pwd, pp[DB_srpid], pp[DB_srpinfo]))
459                    goto err;
460
461                error_code = SRP_ERR_VBASE_BN_LIB;
462                if (!SRP_user_pwd_set_sv
463                    (user_pwd, pp[DB_srpsalt], pp[DB_srpverifier]))
464                    goto err;
465
466                if (sk_SRP_user_pwd_insert(vb->users_pwd, user_pwd, 0) == 0)
467                    goto err;
468                user_pwd = NULL; /* abandon responsability */
469            }
470        }
471    }
472
473    if (last_index != NULL) {
474        /* this means that we want to simulate a default user */
475
476        if (((gN = SRP_get_gN_by_id(last_index, SRP_gN_tab)) == NULL)) {
477            error_code = SRP_ERR_VBASE_BN_LIB;
478            goto err;
479        }
480        vb->default_g = gN->g;
481        vb->default_N = gN->N;
482        gN = NULL;
483    }
484    error_code = SRP_NO_ERROR;
485
486 err:
487    /*
488     * there may be still some leaks to fix, if this fails, the application
489     * terminates most likely
490     */
491
492    if (gN != NULL) {
493        OPENSSL_free(gN->id);
494        OPENSSL_free(gN);
495    }
496
497    SRP_user_pwd_free(user_pwd);
498
499    if (tmpdb)
500        TXT_DB_free(tmpdb);
501    if (in)
502        BIO_free_all(in);
503
504    sk_SRP_gN_free(SRP_gN_tab);
505
506    return error_code;
507
508}
509
510static SRP_user_pwd *find_user(SRP_VBASE *vb, char *username)
511{
512    int i;
513    SRP_user_pwd *user;
514
515    if (vb == NULL)
516        return NULL;
517
518    for (i = 0; i < sk_SRP_user_pwd_num(vb->users_pwd); i++) {
519        user = sk_SRP_user_pwd_value(vb->users_pwd, i);
520        if (strcmp(user->id, username) == 0)
521            return user;
522    }
523
524    return NULL;
525}
526
527/*
528 * This method ignores the configured seed and fails for an unknown user.
529 * Ownership of the returned pointer is not released to the caller.
530 * In other words, caller must not free the result.
531 */
532SRP_user_pwd *SRP_VBASE_get_by_user(SRP_VBASE *vb, char *username)
533{
534    return find_user(vb, username);
535}
536
537/*
538 * Ownership of the returned pointer is released to the caller.
539 * In other words, caller must free the result once done.
540 */
541SRP_user_pwd *SRP_VBASE_get1_by_user(SRP_VBASE *vb, char *username)
542{
543    SRP_user_pwd *user;
544    unsigned char digv[SHA_DIGEST_LENGTH];
545    unsigned char digs[SHA_DIGEST_LENGTH];
546    EVP_MD_CTX ctxt;
547
548    if (vb == NULL)
549        return NULL;
550
551    if ((user = find_user(vb, username)) != NULL)
552        return srp_user_pwd_dup(user);
553
554    if ((vb->seed_key == NULL) ||
555        (vb->default_g == NULL) || (vb->default_N == NULL))
556        return NULL;
557
558/* if the user is unknown we set parameters as well if we have a seed_key */
559
560    if ((user = SRP_user_pwd_new()) == NULL)
561        return NULL;
562
563    SRP_user_pwd_set_gN(user, vb->default_g, vb->default_N);
564
565    if (!SRP_user_pwd_set_ids(user, username, NULL))
566        goto err;
567
568    if (RAND_bytes(digv, SHA_DIGEST_LENGTH) <= 0)
569        goto err;
570    EVP_MD_CTX_init(&ctxt);
571    EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
572    EVP_DigestUpdate(&ctxt, vb->seed_key, strlen(vb->seed_key));
573    EVP_DigestUpdate(&ctxt, username, strlen(username));
574    EVP_DigestFinal_ex(&ctxt, digs, NULL);
575    EVP_MD_CTX_cleanup(&ctxt);
576    if (SRP_user_pwd_set_sv_BN
577        (user, BN_bin2bn(digs, SHA_DIGEST_LENGTH, NULL),
578         BN_bin2bn(digv, SHA_DIGEST_LENGTH, NULL)))
579        return user;
580
581 err:SRP_user_pwd_free(user);
582    return NULL;
583}
584
585/*
586 * create a verifier (*salt,*verifier,g and N are in base64)
587 */
588char *SRP_create_verifier(const char *user, const char *pass, char **salt,
589                          char **verifier, const char *N, const char *g)
590{
591    int len;
592    char *result = NULL, *vf = NULL;
593    BIGNUM *N_bn = NULL, *g_bn = NULL, *s = NULL, *v = NULL;
594    unsigned char tmp[MAX_LEN];
595    unsigned char tmp2[MAX_LEN];
596    char *defgNid = NULL;
597    int vfsize = 0;
598
599    if ((user == NULL) ||
600        (pass == NULL) || (salt == NULL) || (verifier == NULL))
601        goto err;
602
603    if (N) {
604        if (!(len = t_fromb64(tmp, sizeof(tmp), N)))
605            goto err;
606        N_bn = BN_bin2bn(tmp, len, NULL);
607        if (!(len = t_fromb64(tmp, sizeof(tmp), g)))
608            goto err;
609        g_bn = BN_bin2bn(tmp, len, NULL);
610        defgNid = "*";
611    } else {
612        SRP_gN *gN = SRP_get_gN_by_id(g, NULL);
613        if (gN == NULL)
614            goto err;
615        N_bn = gN->N;
616        g_bn = gN->g;
617        defgNid = gN->id;
618    }
619
620    if (*salt == NULL) {
621        if (RAND_bytes(tmp2, SRP_RANDOM_SALT_LEN) <= 0)
622            goto err;
623
624        s = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
625    } else {
626        if (!(len = t_fromb64(tmp2, sizeof(tmp2), *salt)))
627            goto err;
628        s = BN_bin2bn(tmp2, len, NULL);
629    }
630
631    if (!SRP_create_verifier_BN(user, pass, &s, &v, N_bn, g_bn))
632        goto err;
633
634    BN_bn2bin(v, tmp);
635    vfsize = BN_num_bytes(v) * 2;
636    if (((vf = OPENSSL_malloc(vfsize)) == NULL))
637        goto err;
638    t_tob64(vf, tmp, BN_num_bytes(v));
639
640    if (*salt == NULL) {
641        char *tmp_salt;
642
643        if ((tmp_salt = OPENSSL_malloc(SRP_RANDOM_SALT_LEN * 2)) == NULL) {
644            goto err;
645        }
646        t_tob64(tmp_salt, tmp2, SRP_RANDOM_SALT_LEN);
647        *salt = tmp_salt;
648    }
649
650    *verifier = vf;
651    vf = NULL;
652    result = defgNid;
653
654 err:
655    if (N) {
656        BN_free(N_bn);
657        BN_free(g_bn);
658    }
659    if (vf != NULL)
660        OPENSSL_cleanse(vf, vfsize);
661    OPENSSL_free(vf);
662    BN_clear_free(s);
663    BN_clear_free(v);
664    return result;
665}
666
667/*
668 * create a verifier (*salt,*verifier,g and N are BIGNUMs). If *salt != NULL
669 * then the provided salt will be used. On successful exit *verifier will point
670 * to a newly allocated BIGNUM containing the verifier and (if a salt was not
671 * provided) *salt will be populated with a newly allocated BIGNUM containing a
672 * random salt.
673 * The caller is responsible for freeing the allocated *salt and *verifier
674 * BIGNUMS.
675 */
676int SRP_create_verifier_BN(const char *user, const char *pass, BIGNUM **salt,
677                           BIGNUM **verifier, BIGNUM *N, BIGNUM *g)
678{
679    int result = 0;
680    BIGNUM *x = NULL;
681    BN_CTX *bn_ctx = BN_CTX_new();
682    unsigned char tmp2[MAX_LEN];
683    BIGNUM *salttmp = NULL;
684
685    if ((user == NULL) ||
686        (pass == NULL) ||
687        (salt == NULL) ||
688        (verifier == NULL) || (N == NULL) || (g == NULL) || (bn_ctx == NULL))
689        goto err;
690
691    srp_bn_print(N);
692    srp_bn_print(g);
693
694    if (*salt == NULL) {
695        if (RAND_bytes(tmp2, SRP_RANDOM_SALT_LEN) <= 0)
696            goto err;
697
698        salttmp = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
699    } else {
700        salttmp = *salt;
701    }
702
703    x = SRP_Calc_x(salttmp, user, pass);
704
705    *verifier = BN_new();
706    if (*verifier == NULL)
707        goto err;
708
709    if (!BN_mod_exp(*verifier, g, x, N, bn_ctx)) {
710        BN_clear_free(*verifier);
711        goto err;
712    }
713
714    srp_bn_print(*verifier);
715
716    result = 1;
717    *salt = salttmp;
718
719 err:
720    if (*salt != salttmp)
721        BN_clear_free(salttmp);
722    BN_clear_free(x);
723    BN_CTX_free(bn_ctx);
724    return result;
725}
726
727#endif
728