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