source: branches/samhain-2_2-branch/src/sh_srp.c@ 197

Last change on this file since 197 was 34, checked in by rainer, 18 years ago

Code cleanup and minor fixes
File size: 14.3 KB
Line 
1/* SAMHAIN file system integrity testing */
2/* Copyright (C) 1999, 2000 Rainer Wichmann */
3/* */
4/* This program is free software; you can redistribute it */
5/* and/or modify */
6/* it under the terms of the GNU General Public License as */
7/* published by */
8/* the Free Software Foundation; either version 2 of the License, or */
9/* (at your option) any later version. */
10/* */
11/* This program is distributed in the hope that it will be useful, */
12/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
13/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
14/* GNU General Public License for more details. */
15/* */
16/* You should have received a copy of the GNU General Public License */
17/* along with this program; if not, write to the Free Software */
18/* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
19
20#include "config_xor.h"
21
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25
26
27#include "samhain.h"
28
29#ifdef USE_SRP_PROTOCOL
30
31#if (defined (SH_WITH_CLIENT) || defined (SH_WITH_SERVER))
32
33#include "sh_tiger.h"
34#include "sh_mem.h"
35#include "sh_utils.h"
36#include "sh_srp.h"
37
38#if !defined(HAVE_LIBGMP) || !defined(HAVE_GMP_H)
39#include "bignum.h"
40#else
41
42#include <gmp.h>
43
44#define BIG_OK 0
45#define bigerr_t int
46int big_errno = BIG_OK;
47
48#define bignum MP_INT
49
50inline
51int big_create (bignum * a)
52{
53 mpz_init(a);
54 return 0;
55}
56
57inline
58int big_zerop (bignum * a)
59{
60 mpz_t b;
61 int i;
62 mpz_init_set_str(b, "0", 10);
63 i = mpz_cmp(a, b);
64 mpz_clear(b);
65 if (i)
66 return 0;
67 else
68 return 1;
69}
70
71inline
72int big_trunc (bignum * a, bignum * b, bignum * q, bignum *r)
73{
74 mpz_tdiv_qr(q, r, a, b);
75 return 0;
76}
77
78inline
79int big_exptmod (bignum * a, bignum * b, bignum * c, bignum *d)
80{
81 mpz_powm(d, a, b, c);
82 return 0;
83}
84
85char * get_str_internal = NULL;
86int siz_str_internal = 0;
87
88inline
89char * big_string (bignum * a, int base)
90{
91 char * str = NULL;
92 int size;
93 int i;
94 str = mpz_get_str (str, base, a);
95
96 if (get_str_internal == NULL)
97 {
98 get_str_internal = malloc(512); /* only once */
99 if (get_str_internal)
100 {
101 siz_str_internal = 512;
102 }
103 else
104 {
105 if (str != NULL)
106 free(str);
107 return 0;
108 }
109 get_str_internal[0] = '\0';
110 }
111
112 if (str != NULL)
113 {
114 size = strlen(str) + 1;
115 if (size > siz_str_internal)
116 get_str_internal = realloc (get_str_internal, size);
117 if (get_str_internal == NULL)
118 {
119 free(str);
120 return NULL;
121 }
122 siz_str_internal = size;
123 sl_strlcpy (get_str_internal, str, siz_str_internal);
124 for (i = 0; i < (size-1); ++i)
125 if (get_str_internal[i] >= 'a' && get_str_internal[i] <= 'f' )
126 get_str_internal[i] = get_str_internal[i] - 'a' + 'A';
127 free (str);
128 }
129 return get_str_internal;
130}
131
132inline
133int big_add(bignum * a, bignum * b, bignum * c)
134{
135 mpz_add(c, a, b);
136 return 0;
137}
138
139inline
140int big_sub(bignum * a, bignum * b, bignum * c)
141{
142 mpz_sub(c, a, b);
143 return 0;
144}
145
146inline
147int big_mul(bignum * a, bignum * b, bignum * c)
148{
149 mpz_mul(c, a, b);
150 return 0;
151}
152
153inline
154int big_greaterp(bignum * a, bignum * b)
155{
156 return mpz_cmp(a, b) > 0;
157}
158
159inline
160int big_set_big(bignum * a, bignum * b)
161{
162 mpz_set(b, a);
163 return 0;
164}
165
166
167inline
168int big_set_string(const char * str, int base, bignum * a)
169{
170 mpz_set_str (a, str, base);
171 return 0;
172}
173
174
175#define big_init_pkg() 0
176#define big_release_pkg()
177#define big_destroy mpz_clear
178
179/* #if defined(HAVE_LIBGMP)
180 */
181#endif
182
183#undef FIL__
184#define FIL__ _("sh_srp.c")
185
186typedef struct sh_srp_struc {
187 char x[KEY_LEN+1];
188 bignum a;
189 bignum p;
190 bignum g;
191} sh_srp_t;
192
193static sh_srp_t sh_srp;
194
195void sh_srp_x (char * salt, char * password)
196{
197
198 char *combi;
199 size_t len, l2;
200 register int i;
201 unsigned char * dez = NULL;
202
203 SL_ENTER(_("sh_srp_x"));
204
205 /* patch by Andreas Piesk
206 */
207 if (password == NULL)
208 dez = (unsigned char *) &(skey->pw[0]);
209 else
210 dez = (unsigned char *) password;
211
212 for (i = 0; i < PW_LEN; ++i)
213 {
214 skey->vernam[i] = (char)(*dez);
215 ++dez;
216 }
217 skey->vernam[PW_LEN] = '\0';
218
219 (void) sl_strlcpy (skey->vernam,
220 sh_tiger_hash(skey->vernam, TIGER_DATA, PW_LEN), KEY_LEN);
221 skey->vernam[KEY_LEN] = '\0';
222
223 len = sl_strlen(salt) + 1;
224 l2 = sl_strlen(skey->vernam);
225 if (sl_ok_adds(len, l2))
226 len += l2;
227
228 /* H(s,P)
229 */
230 combi = SH_ALLOC(len);
231 (void) sl_strlcpy (combi, salt, len);
232 (void) sl_strlcat (combi, skey->vernam, len);
233 (void) sl_strlcpy (sh_srp.x,
234 sh_tiger_hash(combi, TIGER_DATA,
235 (unsigned long) sl_strlen(combi)),
236 KEY_LEN+1);
237 SH_FREE (combi);
238
239 SL_RET0(_("sh_srp_x"));
240}
241
242char * sh_srp_M (char * x1, char * x2, char * x3)
243{
244 char *combi;
245 size_t len, l2, l3;
246 static char hash[KEY_LEN+1];
247
248 SL_ENTER(_("sh_srp_M"));
249
250 ASSERT_RET((x1 != NULL && x2 != NULL && x3 !=NULL),
251 _("x1 != NULL && x2 != NULL && x3 !=NULL"), NULL);
252
253 len = sl_strlen(x1) + 1;
254 l2 = sl_strlen(x2);
255 l3 = sl_strlen(x3);
256
257 if (sl_ok_adds(len, l2))
258 len += l2;
259 if (sl_ok_adds(len, l3))
260 len += l3;
261
262 /* H(x1,x2,x3)
263 */
264 combi = SH_ALLOC(len);
265 (void) sl_strlcpy (combi, x1, len);
266 (void) sl_strlcat (combi, x2, len);
267 (void) sl_strlcat (combi, x3, len);
268 (void) sl_strlcpy (hash,
269 sh_tiger_hash(combi, TIGER_DATA, (unsigned long) (len-1)),
270 KEY_LEN+1);
271 SH_FREE (combi);
272
273 SL_RETURN(hash, _("sh_srp_M"));
274}
275
276
277void sh_srp_exit()
278{
279 SL_ENTER(_("sh_srp_exit"));
280 big_destroy(&sh_srp.g);
281 big_destroy(&sh_srp.p);
282 big_destroy(&sh_srp.a);
283
284 big_release_pkg();
285
286 big_errno = BIG_OK;
287 SL_RET0(_("sh_srp_exit"));
288}
289
290
291int sh_srp_init()
292{
293 bigerr_t res;
294 char modulus[80*4];
295
296 SL_ENTER(_("sh_srp_init"));
297
298 big_errno = BIG_OK;
299
300 res = big_init_pkg();
301
302 if (res == BIG_OK)
303 {
304 res = big_create(&sh_srp.p);
305 if (res == BIG_OK)
306 res = big_create(&sh_srp.g);
307 if (res == BIG_OK)
308 res = big_create(&sh_srp.a);
309 if (res == BIG_OK)
310 {
311 (void) sl_strlcpy(modulus, SRP_MODULUS_1024_1, sizeof(modulus));
312 (void) sl_strlcat(modulus, SRP_MODULUS_1024_2, sizeof(modulus));
313 (void) sl_strlcat(modulus, SRP_MODULUS_1024_3, sizeof(modulus));
314 (void) sl_strlcat(modulus, SRP_MODULUS_1024_4, sizeof(modulus));
315 }
316 if (res == BIG_OK)
317 res = big_set_string (modulus, 16, &sh_srp.p);
318 if (res == BIG_OK)
319 res = big_set_string (SRP_GENERATOR_1024, 16, &sh_srp.g);
320 if (res == BIG_OK)
321 {
322 SL_RETURN (0, _("sh_srp_init"));
323 }
324 else
325 sh_srp_exit();
326 }
327 SL_RETURN ((-1), _("sh_srp_init"));
328}
329
330
331int sh_srp_make_a ()
332{
333 UINT32 randl[6];
334 int i;
335 int res;
336 char hash[KEY_LEN+1];
337
338 SL_ENTER(_("sh_srp_make_a"));
339
340 for (i = 0; i < 6; ++i)
341 randl[i] = (UINT32) taus_get (&(skey->rng0[0]),
342 &(skey->rng1[0]),
343 &(skey->rng2[0]));
344 (void) sl_strlcpy (hash,
345 sh_tiger_hash((char *)&randl[0], TIGER_DATA,
346 (unsigned long) 6*sizeof(UINT32)),
347 KEY_LEN+1);
348
349 hash[KEY_LEN] = '\0';
350
351 res = big_set_string (hash, 16, &sh_srp.a);
352 if (res == BIG_OK)
353 {
354 SL_RETURN((0), _("sh_srp_make_a"));
355 }
356 else
357 {
358 SL_RETURN((-1), _("sh_srp_make_a"));
359 }
360}
361
362/* return 0 if AB is NOT zero
363 */
364int sh_srp_check_zero (char * AB_str)
365{
366 bignum AB, q, r;
367 bigerr_t res;
368 int val;
369
370 SL_ENTER(_("sh_srp_check_zero"));
371
372 ASSERT_RET((AB_str != NULL), _("AB_str != NULL"), (-1));
373
374 res = big_create(&AB);
375 if (res == BIG_OK)
376 res = big_create(&q);
377 if (res == BIG_OK)
378 res = big_create(&r);
379
380 if (res == BIG_OK)
381 res = big_set_string (AB_str, 16, &AB);
382 if (res == BIG_OK)
383 res = big_trunc(&AB, &sh_srp.p, &q, &r); /* is last one the remainder ? */
384
385 if (res != BIG_OK) val = (-1);
386 else if (0 != big_zerop(&AB) ) val = (-1); /* 0 != (sign == 0) */
387 else val = 0;
388
389 big_destroy(&AB);
390 big_destroy(&q);
391 big_destroy(&r);
392
393 SL_RETURN((val), _("sh_srp_check_zero"));
394}
395
396#if defined(SH_WITH_CLIENT) || defined(SH_WITH_SERVER)
397
398
399char * sh_srp_A ()
400{
401 bignum A;
402 char *str;
403 char *combi;
404 bigerr_t res;
405
406 SL_ENTER(_("sh_srp_A"));
407
408 res = big_create(&A);
409
410 if (res == BIG_OK)
411 res = big_exptmod (&sh_srp.g, &sh_srp.a, &sh_srp.p, &A);
412
413 if (res == BIG_OK)
414 str = big_string (&A, 16);
415 else
416 str = NULL;
417
418 if (str != NULL)
419 combi = sh_util_strdup(str);
420 else
421 combi = NULL;
422
423 big_destroy(&A);
424 SL_RETURN(combi, _("sh_srp_A"));
425}
426
427/* #ifdef SH_WITH_CLIENT */
428#endif
429
430#ifdef SH_WITH_SERVER
431
432char * sh_srp_B (char * verifier)
433{
434 bignum B, v, t, dummy;
435 char *str;
436 char *combi;
437 bigerr_t res;
438
439 SL_ENTER(_("sh_srp_B"));
440
441 ASSERT_RET((verifier != NULL), _("verifier != NULL"), (NULL));
442
443 res = big_create(&dummy);
444
445 if (res == BIG_OK)
446 res = big_create(&t);
447 if (res == BIG_OK)
448 res = big_create(&v);
449 if (res == BIG_OK)
450 res = big_create(&B);
451
452 if (res == BIG_OK)
453 res = big_exptmod (&sh_srp.g, &sh_srp.a, &sh_srp.p, &t);
454
455 if (res == BIG_OK)
456 big_set_string (verifier, 16, &v);
457
458 if (res == BIG_OK)
459 res = big_add (&t, &v, &dummy);
460
461 if (res == BIG_OK)
462 {
463 if ( big_greaterp(&dummy, &sh_srp.p) )
464 res = big_sub(&dummy, &sh_srp.p, &B);
465 else
466 res = big_set_big(&dummy, &B);
467 }
468
469 if (res == BIG_OK)
470 str = big_string (&B, 16);
471 else
472 str = NULL;
473
474 if (str != NULL)
475 combi = sh_util_strdup(str);
476 else
477 combi = NULL;
478
479 big_destroy(&B);
480 big_destroy(&v);
481 big_destroy(&t);
482 big_destroy(&dummy);
483
484 SL_RETURN(combi, _("sh_srp_B"));
485}
486/* #ifdef SH_WITH_SERVER */
487#endif
488
489
490#if defined(SH_WITH_CLIENT) || defined(SH_WITH_SERVER)
491
492char * sh_srp_S_c (char * u_str, char * B_str)
493{
494 bignum u, B, x, t, base, z1, z2;
495 char *str;
496 char *combi;
497 bigerr_t res;
498
499 SL_ENTER(_("sh_srp_S_c"));
500
501 ASSERT_RET((u_str != NULL && B_str != NULL),
502 _("u_str != NULL && B_str != NULL"), (NULL));
503
504 big_errno = BIG_OK;
505
506 res = big_create(&z2);
507 if (res == BIG_OK)
508 res = big_create(&z1);
509 if (res == BIG_OK)
510 res = big_create(&base);
511 if (res == BIG_OK)
512 res = big_create(&t);
513 if (res == BIG_OK)
514 res = big_create(&x);
515 if (res == BIG_OK)
516 res = big_create(&B);
517 if (res == BIG_OK)
518 res = big_create(&u);
519
520 if (res == BIG_OK)
521 res = big_set_string (B_str, 16, &B);
522 if (res == BIG_OK)
523 res = big_set_string (sh_srp.x, 16, &x);
524 if (res == BIG_OK)
525 res = big_set_string (u_str, 16, &u);
526
527 /* the base (B - g^x)
528 */
529 if (res == BIG_OK)
530 res = big_exptmod (&sh_srp.g, &x, &sh_srp.p, &t);
531
532 if (res == BIG_OK)
533 {
534 if ( big_greaterp(&B, &t) != 0)
535 {
536 res = big_sub(&B, &t, &base);
537 }
538 else
539 {
540 res = big_add(&B, &sh_srp.p, &z2);
541 if (res == BIG_OK)
542 res = big_sub(&z2, &t, &base);
543 }
544 }
545
546 /* the exponent (a + ux)
547 */
548 if (res == BIG_OK)
549 res = big_mul (&u, &x, &t);
550 if (res == BIG_OK)
551 res = big_trunc(&t, &sh_srp.p, &z1, &z2); /* is last one the remainder ? */
552 if (res == BIG_OK)
553 res = big_add(&sh_srp.a, &z2, &z1);
554 if (res == BIG_OK)
555 {
556 if ( big_greaterp(&z1, &sh_srp.p) != 0)
557 res = big_sub(&z1, &sh_srp.p, &z2);
558 else
559 res = big_set_big(&z1, &z2);
560 }
561
562 if (res == BIG_OK)
563 res = big_exptmod (&base, &z2, &sh_srp.p, &t);
564
565 if (res == BIG_OK)
566 str = big_string (&t, 16);
567 else
568 str = NULL;
569
570 if (str != NULL)
571 combi = sh_util_strdup(str);
572 else
573 combi = NULL;
574
575 big_destroy(&z1);
576 big_destroy(&z2);
577 big_destroy(&base);
578 big_destroy(&t);
579 big_destroy(&x);
580 big_destroy(&B);
581 big_destroy(&u);
582
583 SL_RETURN(combi, _("sh_srp_S_c"));
584}
585
586/* #ifdef SH_WITH_CLIENT */
587#endif
588
589#ifdef SH_WITH_SERVER
590
591
592char * sh_srp_S_s (char * u_str, char * A_str, char * v_str)
593{
594 bignum u, A, v, t, base, z1, z2;
595 char *str;
596 char *combi;
597 bigerr_t res;
598
599 SL_ENTER(_("sh_srp_S_s"));
600
601 ASSERT_RET((u_str != NULL && A_str != NULL && v_str != NULL),
602 _("u_str != NULL && A_str != NULL && v_str != NULL"),
603 (NULL));
604
605 big_errno = BIG_OK;
606
607 res = big_create(&z2);
608 if (res == BIG_OK)
609 res = big_create(&z1);
610 if (res == BIG_OK)
611 res = big_create(&base);
612 if (res == BIG_OK)
613 res = big_create(&t);
614 if (res == BIG_OK)
615 res = big_create(&v);
616 if (res == BIG_OK)
617 res = big_create(&A);
618 if (res == BIG_OK)
619 res = big_create(&u);
620
621 if (res == BIG_OK)
622 res = big_set_string (A_str, 16, &A);
623 if (res == BIG_OK)
624 res = big_set_string (v_str, 16, &v);
625 if (res == BIG_OK)
626 res = big_set_string (u_str, 16, &u);
627
628 /* the base (Av^u)
629 */
630 if (res == BIG_OK)
631 res = big_exptmod (&v, &u, &sh_srp.p, &t);
632 if (res == BIG_OK)
633 res = big_mul (&A, &t, &z1);
634 if (res == BIG_OK)
635 res = big_trunc(&z1, &sh_srp.p, &z2, &base); /* is last the remainder ? */
636
637 if (res == BIG_OK)
638 res = big_exptmod (&base, &sh_srp.a, &sh_srp.p, &t);
639
640 if (res == BIG_OK)
641 str = big_string (&t, 16);
642 else
643 str = NULL;
644
645 if (str != NULL)
646 combi = sh_util_strdup(str);
647 else
648 combi = NULL;
649
650 big_destroy(&z1);
651 big_destroy(&z2);
652 big_destroy(&base);
653 big_destroy(&t);
654 big_destroy(&v);
655 big_destroy(&A);
656 big_destroy(&u);
657
658 SL_RETURN(combi, _("sh_srp_S_s"));
659}
660
661/* #ifdef SH_WITH_SERVER */
662#endif
663
664
665char * sh_srp_verifier (void)
666{
667 bignum x, v;
668 char *combi;
669 char *str;
670 bigerr_t res;
671
672 SL_ENTER(_("sh_srp_verifier"));
673
674 res = big_create(&x);
675 if (res == BIG_OK)
676 res = big_create(&v);
677
678 if (res == BIG_OK)
679 res = big_set_string (sh_srp.x, 16, &x);
680
681 if (res == BIG_OK)
682 res = big_exptmod (&sh_srp.g, &x, &sh_srp.p, &v);
683
684 if (res == BIG_OK)
685 str = big_string (&v, 16);
686 else
687 str = NULL;
688
689 if (str != NULL)
690 combi = sh_util_strdup(str);
691 else
692 combi = NULL;
693
694 big_destroy(&x);
695 big_destroy(&v);
696
697 SL_RETURN(combi, _("sh_srp_verifier"));
698}
699
700
701/* #if (defined (SH_WITH_CLIENT) || defined (SH_WITH_SERVER)) */
702
703#endif
704
705/* #ifdef USE_SRP_PROTOCOL */
706
707#endif
708
709
710
711
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