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