1/*
2 * Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2004, EdelKey Project. All Rights Reserved.
4 *
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
9 *
10 * Originally written by Christophe Renou and Peter Sylvester,
11 * for the EdelKey project.
12 */
13
14#ifndef OPENSSL_NO_SRP
15# include "internal/cryptlib.h"
16# include "crypto/evp.h"
17# include <openssl/sha.h>
18# include <openssl/srp.h>
19# include <openssl/evp.h>
20# include <openssl/buffer.h>
21# include <openssl/rand.h>
22# include <openssl/txt_db.h>
23# include <openssl/err.h>
24
25# define SRP_RANDOM_SALT_LEN 20
26# define MAX_LEN 2500
27
28/*
29 * Note that SRP uses its own variant of base 64 encoding. A different base64
30 * alphabet is used and no padding '=' characters are added. Instead we pad to
31 * the front with 0 bytes and subsequently strip off leading encoded padding.
32 * This variant is used for compatibility with other SRP implementations -
33 * notably libsrp, but also others. It is also required for backwards
34 * compatibility in order to load verifier files from other OpenSSL versions.
35 */
36
37/*
38 * Convert a base64 string into raw byte array representation.
39 * Returns the length of the decoded data, or -1 on error.
40 */
41static int t_fromb64(unsigned char *a, size_t alen, const char *src)
42{
43 EVP_ENCODE_CTX *ctx;
44 int outl = 0, outl2 = 0;
45 size_t size, padsize;
46 const unsigned char *pad = (const unsigned char *)"00";
47
48 while (*src == ' ' || *src == '\t' || *src == '\n')
49 ++src;
50 size = strlen(src);
51 padsize = 4 - (size & 3);
52 padsize &= 3;
53
54 /* Four bytes in src become three bytes output. */
55 if (size > INT_MAX || ((size + padsize) / 4) * 3 > alen)
56 return -1;
57
58 ctx = EVP_ENCODE_CTX_new();
59 if (ctx == NULL)
60 return -1;
61
62 /*
63 * This should never occur because 1 byte of data always requires 2 bytes of
64 * encoding, i.e.
65 * 0 bytes unencoded = 0 bytes encoded
66 * 1 byte unencoded = 2 bytes encoded
67 * 2 bytes unencoded = 3 bytes encoded
68 * 3 bytes unencoded = 4 bytes encoded
69 * 4 bytes unencoded = 6 bytes encoded
70 * etc
71 */
72 if (padsize == 3) {
73 outl = -1;
74 goto err;
75 }
76
77 /* Valid padsize values are now 0, 1 or 2 */
78
79 EVP_DecodeInit(ctx);
80 evp_encode_ctx_set_flags(ctx, EVP_ENCODE_CTX_USE_SRP_ALPHABET);
81
82 /* Add any encoded padding that is required */
83 if (padsize != 0
84 && EVP_DecodeUpdate(ctx, a, &outl, pad, padsize) < 0) {
85 outl = -1;
86 goto err;
87 }
88 if (EVP_DecodeUpdate(ctx, a, &outl2, (const unsigned char *)src, size) < 0) {
89 outl = -1;
90 goto err;
91 }
92 outl += outl2;
93 EVP_DecodeFinal(ctx, a + outl, &outl2);
94 outl += outl2;
95
96 /* Strip off the leading padding */
97 if (padsize != 0) {
98 if ((int)padsize >= outl) {
99 outl = -1;
100 goto err;
101 }
102
103 /*
104 * If we added 1 byte of padding prior to encoding then we have 2 bytes
105 * of "real" data which gets spread across 4 encoded bytes like this:
106 * (6 bits pad)(2 bits pad | 4 bits data)(6 bits data)(6 bits data)
107 * So 1 byte of pre-encoding padding results in 1 full byte of encoded
108 * padding.
109 * If we added 2 bytes of padding prior to encoding this gets encoded
110 * as:
111 * (6 bits pad)(6 bits pad)(4 bits pad | 2 bits data)(6 bits data)
112 * So 2 bytes of pre-encoding padding results in 2 full bytes of encoded
113 * padding, i.e. we have to strip the same number of bytes of padding
114 * from the encoded data as we added to the pre-encoded data.
115 */
116 memmove(a, a + padsize, outl - padsize);
117 outl -= padsize;
118 }
119
120 err:
121 EVP_ENCODE_CTX_free(ctx);
122
123 return outl;
124}
125
126/*
127 * Convert a raw byte string into a null-terminated base64 ASCII string.
128 * Returns 1 on success or 0 on error.
129 */
130static int t_tob64(char *dst, const unsigned char *src, int size)
131{
132 EVP_ENCODE_CTX *ctx = EVP_ENCODE_CTX_new();
133 int outl = 0, outl2 = 0;
134 unsigned char pad[2] = {0, 0};
135 size_t leadz = 0;
136
137 if (ctx == NULL)
138 return 0;
139
140 EVP_EncodeInit(ctx);
141 evp_encode_ctx_set_flags(ctx, EVP_ENCODE_CTX_NO_NEWLINES
142 | EVP_ENCODE_CTX_USE_SRP_ALPHABET);
143
144 /*
145 * We pad at the front with zero bytes until the length is a multiple of 3
146 * so that EVP_EncodeUpdate/EVP_EncodeFinal does not add any of its own "="
147 * padding
148 */
149 leadz = 3 - (size % 3);
150 if (leadz != 3
151 && !EVP_EncodeUpdate(ctx, (unsigned char *)dst, &outl, pad,
152 leadz)) {
153 EVP_ENCODE_CTX_free(ctx);
154 return 0;
155 }
156
157 if (!EVP_EncodeUpdate(ctx, (unsigned char *)dst + outl, &outl2, src,
158 size)) {
159 EVP_ENCODE_CTX_free(ctx);
160 return 0;
161 }
162 outl += outl2;
163 EVP_EncodeFinal(ctx, (unsigned char *)dst + outl, &outl2);
164 outl += outl2;
165
166 /* Strip the encoded padding at the front */
167 if (leadz != 3) {
168 memmove(dst, dst + leadz, outl - leadz);
169 dst[outl - leadz] = '\0';
170 }
171
172 EVP_ENCODE_CTX_free(ctx);
173 return 1;
174}
175
176void SRP_user_pwd_free(SRP_user_pwd *user_pwd)
177{
178 if (user_pwd == NULL)
179 return;
180 BN_free(user_pwd->s);
181 BN_clear_free(user_pwd->v);
182 OPENSSL_free(user_pwd->id);
183 OPENSSL_free(user_pwd->info);
184 OPENSSL_free(user_pwd);
185}
186
187SRP_user_pwd *SRP_user_pwd_new(void)
188{
189 SRP_user_pwd *ret;
190
191 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
192 /* SRPerr(SRP_F_SRP_USER_PWD_NEW, ERR_R_MALLOC_FAILURE); */ /*ckerr_ignore*/
193 return NULL;
194 }
195 ret->N = NULL;
196 ret->g = NULL;
197 ret->s = NULL;
198 ret->v = NULL;
199 ret->id = NULL;
200 ret->info = NULL;
201 return ret;
202}
203
204void SRP_user_pwd_set_gN(SRP_user_pwd *vinfo, const BIGNUM *g,
205 const BIGNUM *N)
206{
207 vinfo->N = N;
208 vinfo->g = g;
209}
210
211int SRP_user_pwd_set1_ids(SRP_user_pwd *vinfo, const char *id,
212 const char *info)
213{
214 OPENSSL_free(vinfo->id);
215 OPENSSL_free(vinfo->info);
216 if (id != NULL && NULL == (vinfo->id = OPENSSL_strdup(id)))
217 return 0;
218 return (info == NULL || NULL != (vinfo->info = OPENSSL_strdup(info)));
219}
220
221static int SRP_user_pwd_set_sv(SRP_user_pwd *vinfo, const char *s,
222 const char *v)
223{
224 unsigned char tmp[MAX_LEN];
225 int len;
226
227 vinfo->v = NULL;
228 vinfo->s = NULL;
229
230 len = t_fromb64(tmp, sizeof(tmp), v);
231 if (len < 0)
232 return 0;
233 if (NULL == (vinfo->v = BN_bin2bn(tmp, len, NULL)))
234 return 0;
235 len = t_fromb64(tmp, sizeof(tmp), s);
236 if (len < 0)
237 goto err;
238 vinfo->s = BN_bin2bn(tmp, len, NULL);
239 if (vinfo->s == NULL)
240 goto err;
241 return 1;
242 err:
243 BN_free(vinfo->v);
244 vinfo->v = NULL;
245 return 0;
246}
247
248int SRP_user_pwd_set0_sv(SRP_user_pwd *vinfo, BIGNUM *s, BIGNUM *v)
249{
250 BN_free(vinfo->s);
251 BN_clear_free(vinfo->v);
252 vinfo->v = v;
253 vinfo->s = s;
254 return (vinfo->s != NULL && vinfo->v != NULL);
255}
256
257static SRP_user_pwd *srp_user_pwd_dup(SRP_user_pwd *src)
258{
259 SRP_user_pwd *ret;
260
261 if (src == NULL)
262 return NULL;
263 if ((ret = SRP_user_pwd_new()) == NULL)
264 return NULL;
265
266 SRP_user_pwd_set_gN(ret, src->g, src->N);
267 if (!SRP_user_pwd_set1_ids(ret, src->id, src->info)
268 || !SRP_user_pwd_set0_sv(ret, BN_dup(src->s), BN_dup(src->v))) {
269 SRP_user_pwd_free(ret);
270 return NULL;
271 }
272 return ret;
273}
274
275SRP_VBASE *SRP_VBASE_new(char *seed_key)
276{
277 SRP_VBASE *vb = OPENSSL_malloc(sizeof(*vb));
278
279 if (vb == NULL)
280 return NULL;
281 if ((vb->users_pwd = sk_SRP_user_pwd_new_null()) == NULL
282 || (vb->gN_cache = sk_SRP_gN_cache_new_null()) == NULL) {
283 OPENSSL_free(vb);
284 return NULL;
285 }
286 vb->default_g = NULL;
287 vb->default_N = NULL;
288 vb->seed_key = NULL;
289 if ((seed_key != NULL) && (vb->seed_key = OPENSSL_strdup(seed_key)) == NULL) {
290 sk_SRP_user_pwd_free(vb->users_pwd);
291 sk_SRP_gN_cache_free(vb->gN_cache);
292 OPENSSL_free(vb);
293 return NULL;
294 }
295 return vb;
296}
297
298void SRP_VBASE_free(SRP_VBASE *vb)
299{
300 if (!vb)
301 return;
302 sk_SRP_user_pwd_pop_free(vb->users_pwd, SRP_user_pwd_free);
303 sk_SRP_gN_cache_free(vb->gN_cache);
304 OPENSSL_free(vb->seed_key);
305 OPENSSL_free(vb);
306}
307
308static SRP_gN_cache *SRP_gN_new_init(const char *ch)
309{
310 unsigned char tmp[MAX_LEN];
311 int len;
312 SRP_gN_cache *newgN = OPENSSL_malloc(sizeof(*newgN));
313
314 if (newgN == NULL)
315 return NULL;
316
317 len = t_fromb64(tmp, sizeof(tmp), ch);
318 if (len < 0)
319 goto err;
320
321 if ((newgN->b64_bn = OPENSSL_strdup(ch)) == NULL)
322 goto err;
323
324 if ((newgN->bn = BN_bin2bn(tmp, len, NULL)))
325 return newgN;
326
327 OPENSSL_free(newgN->b64_bn);
328 err:
329 OPENSSL_free(newgN);
330 return NULL;
331}
332
333static void SRP_gN_free(SRP_gN_cache *gN_cache)
334{
335 if (gN_cache == NULL)
336 return;
337 OPENSSL_free(gN_cache->b64_bn);
338 BN_free(gN_cache->bn);
339 OPENSSL_free(gN_cache);
340}
341
342static SRP_gN *SRP_get_gN_by_id(const char *id, STACK_OF(SRP_gN) *gN_tab)
343{
344 int i;
345
346 SRP_gN *gN;
347 if (gN_tab != NULL) {
348 for (i = 0; i < sk_SRP_gN_num(gN_tab); i++) {
349 gN = sk_SRP_gN_value(gN_tab, i);
350 if (gN && (id == NULL || strcmp(gN->id, id) == 0))
351 return gN;
352 }
353 }
354
355 return SRP_get_default_gN(id);
356}
357
358static BIGNUM *SRP_gN_place_bn(STACK_OF(SRP_gN_cache) *gN_cache, char *ch)
359{
360 int i;
361 if (gN_cache == NULL)
362 return NULL;
363
364 /* search if we have already one... */
365 for (i = 0; i < sk_SRP_gN_cache_num(gN_cache); i++) {
366 SRP_gN_cache *cache = sk_SRP_gN_cache_value(gN_cache, i);
367 if (strcmp(cache->b64_bn, ch) == 0)
368 return cache->bn;
369 }
370 { /* it is the first time that we find it */
371 SRP_gN_cache *newgN = SRP_gN_new_init(ch);
372 if (newgN) {
373 if (sk_SRP_gN_cache_insert(gN_cache, newgN, 0) > 0)
374 return newgN->bn;
375 SRP_gN_free(newgN);
376 }
377 }
378 return NULL;
379}
380
381/*
382 * This function parses the verifier file generated by the srp app.
383 * The format for each entry is:
384 * V base64(verifier) base64(salt) username gNid userinfo(optional)
385 * or
386 * I base64(N) base64(g)
387 * Note that base64 is the SRP variant of base64 encoding described
388 * in t_fromb64().
389 */
390
391int SRP_VBASE_init(SRP_VBASE *vb, char *verifier_file)
392{
393 int error_code;
394 STACK_OF(SRP_gN) *SRP_gN_tab = sk_SRP_gN_new_null();
395 char *last_index = NULL;
396 int i;
397 char **pp;
398
399 SRP_gN *gN = NULL;
400 SRP_user_pwd *user_pwd = NULL;
401
402 TXT_DB *tmpdb = NULL;
403 BIO *in = BIO_new(BIO_s_file());
404
405 error_code = SRP_ERR_OPEN_FILE;
406
407 if (in == NULL || BIO_read_filename(in, verifier_file) <= 0)
408 goto err;
409
410 error_code = SRP_ERR_VBASE_INCOMPLETE_FILE;
411
412 if ((tmpdb = TXT_DB_read(in, DB_NUMBER)) == NULL)
413 goto err;
414
415 error_code = SRP_ERR_MEMORY;
416
417 if (vb->seed_key) {
418 last_index = SRP_get_default_gN(NULL)->id;
419 }
420 for (i = 0; i < sk_OPENSSL_PSTRING_num(tmpdb->data); i++) {
421 pp = sk_OPENSSL_PSTRING_value(tmpdb->data, i);
422 if (pp[DB_srptype][0] == DB_SRP_INDEX) {
423 /*
424 * we add this couple in the internal Stack
425 */
426
427 if ((gN = OPENSSL_malloc(sizeof(*gN))) == NULL)
428 goto err;
429
430 if ((gN->id = OPENSSL_strdup(pp[DB_srpid])) == NULL
431 || (gN->N = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpverifier]))
432 == NULL
433 || (gN->g = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpsalt]))
434 == NULL
435 || sk_SRP_gN_insert(SRP_gN_tab, gN, 0) == 0)
436 goto err;
437
438 gN = NULL;
439
440 if (vb->seed_key != NULL) {
441 last_index = pp[DB_srpid];
442 }
443 } else if (pp[DB_srptype][0] == DB_SRP_VALID) {
444 /* it is a user .... */
445 const SRP_gN *lgN;
446
447 if ((lgN = SRP_get_gN_by_id(pp[DB_srpgN], SRP_gN_tab)) != NULL) {
448 error_code = SRP_ERR_MEMORY;
449 if ((user_pwd = SRP_user_pwd_new()) == NULL)
450 goto err;
451
452 SRP_user_pwd_set_gN(user_pwd, lgN->g, lgN->N);
453 if (!SRP_user_pwd_set1_ids
454 (user_pwd, pp[DB_srpid], pp[DB_srpinfo]))
455 goto err;
456
457 error_code = SRP_ERR_VBASE_BN_LIB;
458 if (!SRP_user_pwd_set_sv
459 (user_pwd, pp[DB_srpsalt], pp[DB_srpverifier]))
460 goto err;
461
462 if (sk_SRP_user_pwd_insert(vb->users_pwd, user_pwd, 0) == 0)
463 goto err;
464 user_pwd = NULL; /* abandon responsibility */
465 }
466 }
467 }
468
469 if (last_index != NULL) {
470 /* this means that we want to simulate a default user */
471
472 if (((gN = SRP_get_gN_by_id(last_index, SRP_gN_tab)) == NULL)) {
473 error_code = SRP_ERR_VBASE_BN_LIB;
474 goto err;
475 }
476 vb->default_g = gN->g;
477 vb->default_N = gN->N;
478 gN = NULL;
479 }
480 error_code = SRP_NO_ERROR;
481
482 err:
483 /*
484 * there may be still some leaks to fix, if this fails, the application
485 * terminates most likely
486 */
487
488 if (gN != NULL) {
489 OPENSSL_free(gN->id);
490 OPENSSL_free(gN);
491 }
492
493 SRP_user_pwd_free(user_pwd);
494
495 TXT_DB_free(tmpdb);
496 BIO_free_all(in);
497
498 sk_SRP_gN_free(SRP_gN_tab);
499
500 return error_code;
501
502}
503
504static SRP_user_pwd *find_user(SRP_VBASE *vb, char *username)
505{
506 int i;
507 SRP_user_pwd *user;
508
509 if (vb == NULL)
510 return NULL;
511
512 for (i = 0; i < sk_SRP_user_pwd_num(vb->users_pwd); i++) {
513 user = sk_SRP_user_pwd_value(vb->users_pwd, i);
514 if (strcmp(user->id, username) == 0)
515 return user;
516 }
517
518 return NULL;
519}
520
521int SRP_VBASE_add0_user(SRP_VBASE *vb, SRP_user_pwd *user_pwd)
522{
523 if (sk_SRP_user_pwd_push(vb->users_pwd, user_pwd) <= 0)
524 return 0;
525 return 1;
526}
527
528# ifndef OPENSSL_NO_DEPRECATED_1_1_0
529/*
530 * DEPRECATED: use SRP_VBASE_get1_by_user instead.
531 * This method ignores the configured seed and fails for an unknown user.
532 * Ownership of the returned pointer is not released to the caller.
533 * In other words, caller must not free the result.
534 */
535SRP_user_pwd *SRP_VBASE_get_by_user(SRP_VBASE *vb, char *username)
536{
537 return find_user(vb, username);
538}
539# endif
540
541/*
542 * Ownership of the returned pointer is released to the caller.
543 * In other words, caller must free the result once done.
544 */
545SRP_user_pwd *SRP_VBASE_get1_by_user(SRP_VBASE *vb, char *username)
546{
547 SRP_user_pwd *user;
548 unsigned char digv[SHA_DIGEST_LENGTH];
549 unsigned char digs[SHA_DIGEST_LENGTH];
550 EVP_MD_CTX *ctxt = NULL;
551
552 if (vb == NULL)
553 return NULL;
554
555 if ((user = find_user(vb, username)) != NULL)
556 return srp_user_pwd_dup(user);
557
558 if ((vb->seed_key == NULL) ||
559 (vb->default_g == NULL) || (vb->default_N == NULL))
560 return NULL;
561
562/* if the user is unknown we set parameters as well if we have a seed_key */
563
564 if ((user = SRP_user_pwd_new()) == NULL)
565 return NULL;
566
567 SRP_user_pwd_set_gN(user, vb->default_g, vb->default_N);
568
569 if (!SRP_user_pwd_set1_ids(user, username, NULL))
570 goto err;
571
572 if (RAND_priv_bytes(digv, SHA_DIGEST_LENGTH) <= 0)
573 goto err;
574 ctxt = EVP_MD_CTX_new();
575 if (ctxt == NULL
576 || !EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL)
577 || !EVP_DigestUpdate(ctxt, vb->seed_key, strlen(vb->seed_key))
578 || !EVP_DigestUpdate(ctxt, username, strlen(username))
579 || !EVP_DigestFinal_ex(ctxt, digs, NULL))
580 goto err;
581 EVP_MD_CTX_free(ctxt);
582 ctxt = NULL;
583 if (SRP_user_pwd_set0_sv(user,
584 BN_bin2bn(digs, SHA_DIGEST_LENGTH, NULL),
585 BN_bin2bn(digv, SHA_DIGEST_LENGTH, NULL)))
586 return user;
587
588 err:
589 EVP_MD_CTX_free(ctxt);
590 SRP_user_pwd_free(user);
591 return NULL;
592}
593
594/*
595 * create a verifier (*salt,*verifier,g and N are in base64)
596 */
597char *SRP_create_verifier(const char *user, const char *pass, char **salt,
598 char **verifier, const char *N, const char *g)
599{
600 int len;
601 char *result = NULL, *vf = NULL;
602 const BIGNUM *N_bn = NULL, *g_bn = NULL;
603 BIGNUM *N_bn_alloc = NULL, *g_bn_alloc = NULL, *s = NULL, *v = NULL;
604 unsigned char tmp[MAX_LEN];
605 unsigned char tmp2[MAX_LEN];
606 char *defgNid = NULL;
607 int vfsize = 0;
608
609 if ((user == NULL) ||
610 (pass == NULL) || (salt == NULL) || (verifier == NULL))
611 goto err;
612
613 if (N) {
614 if ((len = t_fromb64(tmp, sizeof(tmp), N)) <= 0)
615 goto err;
616 N_bn_alloc = BN_bin2bn(tmp, len, NULL);
617 if (N_bn_alloc == NULL)
618 goto err;
619 N_bn = N_bn_alloc;
620 if ((len = t_fromb64(tmp, sizeof(tmp) ,g)) <= 0)
621 goto err;
622 g_bn_alloc = BN_bin2bn(tmp, len, NULL);
623 if (g_bn_alloc == NULL)
624 goto err;
625 g_bn = g_bn_alloc;
626 defgNid = "*";
627 } else {
628 SRP_gN *gN = SRP_get_default_gN(g);
629 if (gN == NULL)
630 goto err;
631 N_bn = gN->N;
632 g_bn = gN->g;
633 defgNid = gN->id;
634 }
635
636 if (*salt == NULL) {
637 if (RAND_bytes(tmp2, SRP_RANDOM_SALT_LEN) <= 0)
638 goto err;
639
640 s = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
641 } else {
642 if ((len = t_fromb64(tmp2, sizeof(tmp2), *salt)) <= 0)
643 goto err;
644 s = BN_bin2bn(tmp2, len, NULL);
645 }
646 if (s == NULL)
647 goto err;
648
649 if (!SRP_create_verifier_BN(user, pass, &s, &v, N_bn, g_bn))
650 goto err;
651
652 if (BN_bn2bin(v, tmp) < 0)
653 goto err;
654 vfsize = BN_num_bytes(v) * 2;
655 if (((vf = OPENSSL_malloc(vfsize)) == NULL))
656 goto err;
657 if (!t_tob64(vf, tmp, BN_num_bytes(v)))
658 goto err;
659
660 if (*salt == NULL) {
661 char *tmp_salt;
662
663 if ((tmp_salt = OPENSSL_malloc(SRP_RANDOM_SALT_LEN * 2)) == NULL) {
664 goto err;
665 }
666 if (!t_tob64(tmp_salt, tmp2, SRP_RANDOM_SALT_LEN)) {
667 OPENSSL_free(tmp_salt);
668 goto err;
669 }
670 *salt = tmp_salt;
671 }
672
673 *verifier = vf;
674 vf = NULL;
675 result = defgNid;
676
677 err:
678 BN_free(N_bn_alloc);
679 BN_free(g_bn_alloc);
680 OPENSSL_clear_free(vf, vfsize);
681 BN_clear_free(s);
682 BN_clear_free(v);
683 return result;
684}
685
686/*
687 * create a verifier (*salt,*verifier,g and N are BIGNUMs). If *salt != NULL
688 * then the provided salt will be used. On successful exit *verifier will point
689 * to a newly allocated BIGNUM containing the verifier and (if a salt was not
690 * provided) *salt will be populated with a newly allocated BIGNUM containing a
691 * random salt.
692 * The caller is responsible for freeing the allocated *salt and *verifier
693 * BIGNUMS.
694 */
695int SRP_create_verifier_BN(const char *user, const char *pass, BIGNUM **salt,
696 BIGNUM **verifier, const BIGNUM *N,
697 const BIGNUM *g)
698{
699 int result = 0;
700 BIGNUM *x = NULL;
701 BN_CTX *bn_ctx = BN_CTX_new();
702 unsigned char tmp2[MAX_LEN];
703 BIGNUM *salttmp = NULL;
704
705 if ((user == NULL) ||
706 (pass == NULL) ||
707 (salt == NULL) ||
708 (verifier == NULL) || (N == NULL) || (g == NULL) || (bn_ctx == NULL))
709 goto err;
710
711 if (*salt == NULL) {
712 if (RAND_bytes(tmp2, SRP_RANDOM_SALT_LEN) <= 0)
713 goto err;
714
715 salttmp = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
716 if (salttmp == NULL)
717 goto err;
718 } else {
719 salttmp = *salt;
720 }
721
722 x = SRP_Calc_x(salttmp, user, pass);
723 if (x == NULL)
724 goto err;
725
726 *verifier = BN_new();
727 if (*verifier == NULL)
728 goto err;
729
730 if (!BN_mod_exp(*verifier, g, x, N, bn_ctx)) {
731 BN_clear_free(*verifier);
732 goto err;
733 }
734
735 result = 1;
736 *salt = salttmp;
737
738 err:
739 if (salt != NULL && *salt != salttmp)
740 BN_clear_free(salttmp);
741 BN_clear_free(x);
742 BN_CTX_free(bn_ctx);
743 return result;
744}
745
746#endif
747