summaryrefslogtreecommitdiff
path: root/accel-pppd/extra/chap-secrets.c
blob: d2d752a28988c0ea58440bd4c93dfad93be5c242 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <byteswap.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#ifdef CRYPTO_OPENSSL
#include "openssl/evp.h"
#include "crypto.h"
#endif

#include "pwdb.h"
#include "ipdb.h"
#include "ppp.h"
#include "ppp_auth.h"
#include "events.h"
#include "triton.h"
#include "log.h"

#include "memdebug.h"

static char *def_chap_secrets = "/etc/ppp/chap-secrets";
static char *conf_chap_secrets;
static int conf_encrypted;
static in_addr_t conf_gw_ip_address = 0;
static int conf_netmask;

static void *pd_key;
static struct ipdb_t ipdb;

struct hash_chain
{
	struct list_head entry;
	const EVP_MD *md;
};

struct cs_pd_t
{
	struct ap_private pd;
	struct ipv4db_item_t ip;
	char *passwd;
	char *rate;
};

static LIST_HEAD(hash_chain);

static char *skip_word(char *ptr)
{
	char quote = 0;

	if (*ptr == '\'' || *ptr == '"') {
		quote = *ptr;
		ptr++;
	}

	for(; *ptr; ptr++) {
		if (quote) {
			if (*ptr == '\n')
				break;
			if (*ptr == '\\' && ptr[1] && ptr[1] != '\n') {
				memmove(ptr, ptr + 1, strlen(ptr));
				continue;
			}
			if (*ptr == quote) {
				*ptr = ' ';
				break;
			}
		} else if (*ptr == ' ' || *ptr == '\t' || *ptr == '\n') 
			break;
	}

	return ptr;
}

static char *skip_space(char *ptr)
{
	for(; *ptr; ptr++)
		if (*ptr != ' ' && *ptr != '\t')
			break;

	return ptr;
}

static int split(char *buf, char **ptr)
{
	int i;

	for (i = 0; i < 4; i++) {
		buf = skip_word(buf);
		if (!*buf)
			return i;
	
		*buf = 0;
		
		buf = skip_space(buf + 1);
		if (!*buf)
			return i;

		if (*buf == '"' || *buf == '\'')
			ptr[i] = buf + 1;
		else
			ptr[i] = buf;
	}

	buf = skip_word(buf);
	//if (*buf == '\n')
		*buf = 0;
	//else if (*buf)
	//	return -1;

	return i;
}


static struct cs_pd_t *create_pd(struct ap_session *ses, const char *username)
{
	FILE *f;
	char *buf;
	char *ptr[5];
	int n, i;
	struct cs_pd_t *pd;
#ifdef CRYPTO_OPENSSL
	char username_hash[EVP_MAX_MD_SIZE * 2 + 1];
	uint8_t hash[EVP_MAX_MD_SIZE];
	struct hash_chain *hc;
	EVP_MD_CTX md_ctx;
	char c;
#endif

	if (!conf_chap_secrets)
		return NULL;
	
#ifdef CRYPTO_OPENSSL
	if (conf_encrypted && !list_empty(&hash_chain)) {
		unsigned int size = 0;
		list_for_each_entry(hc, &hash_chain, entry) {
			EVP_MD_CTX_init(&md_ctx);
			EVP_DigestInit_ex(&md_ctx, hc->md, NULL);
			EVP_DigestUpdate(&md_ctx, size == 0 ? (void *)username : (void *)hash, size == 0 ? strlen(username) : size);
			EVP_DigestFinal_ex(&md_ctx, hash, &size);
			EVP_MD_CTX_cleanup(&md_ctx);
		}

		for (n = 0; n < size; n++)
			sprintf(username_hash + n*2, "%02x", hash[n]);

		username = username_hash;
	}
#endif
	
	f = fopen(conf_chap_secrets, "r");
	if (!f) {
		log_error("chap-secrets: open '%s': %s\n", conf_chap_secrets, strerror(errno));
		return NULL;
	}

	buf = _malloc(4096);
	if (!buf) {
		log_emerg("chap-secrets: out of memory\n");
		fclose(f);
		return NULL;
	}
	
	while (fgets(buf, 4096, f)) {
		if (buf[0] == '#')
			continue;
		n = split(buf, ptr);
		if (n < 3)
			continue;
		if (*buf == '\'' || *buf == '"') {
			if (!strcmp(buf + 1, username))
				goto found;
		} else {
			if (!strcmp(buf, username))
				goto found;
		}
	}

out:
	fclose(f);
	_free(buf);
	return NULL;

found:
#ifdef CRYPTO_OPENSSL
	if (conf_encrypted && strlen(ptr[1]) != 32)
		goto out;
#endif

	pd = _malloc(sizeof(*pd));
	if (!pd) {
		log_emerg("chap-secrets: out of memory\n");
		goto out;
	}

	memset(pd, 0, sizeof(*pd));
	pd->pd.key = &pd_key;
#ifdef CRYPTO_OPENSSL
	if (conf_encrypted) {
		pd->passwd = _malloc(16);
		if (!pd->passwd) {
			log_emerg("chap-secrets: out of memory\n");
			_free(pd);
			goto out;
		}
		
		for (i = 0; i < 16; i++) {
			c = ptr[1][i*2 + 2];
			ptr[1][i*2 + 2] = 0;
			pd->passwd[i] = strtol(ptr[1] + i*2, NULL, 16);
			ptr[1][i*2 + 2] = c;
		}
	} else 
#endif
	{
		pd->passwd = _strdup(ptr[1]);
		if (!pd->passwd) {
			log_emerg("chap-secrets: out of memory\n");
			_free(pd);
			goto out;
		}
	}

	pd->ip.addr = conf_gw_ip_address;
	if (n >= 3 && ptr[2][0] != '*')
		pd->ip.peer_addr = inet_addr(ptr[2]);
	pd->ip.mask = conf_netmask;
	pd->ip.owner = &ipdb;

	if (n >= 4)
		pd->rate = _strdup(ptr[3]);

	list_add_tail(&pd->pd.entry, &ses->pd_list);

	fclose(f);
	_free(buf);

	return pd;
}

static struct cs_pd_t *find_pd(struct ap_session *ses)
{
	struct ap_private *pd;

	list_for_each_entry(pd, &ses->pd_list, entry) {
		if (pd->key == &pd_key) {
			return container_of(pd, typeof(struct cs_pd_t), pd);
		}
	}

	return NULL;
}

static void ev_ses_finished(struct ap_session *ses)
{
	struct cs_pd_t *pd = find_pd(ses);

	if (!pd)
		return;

	list_del(&pd->pd.entry);
	_free(pd->passwd);
	if (pd->rate)
		_free(pd->rate);
	_free(pd);
}

static void ev_ses_pre_up(struct ap_session *ses)
{
	struct cs_pd_t *pd = find_pd(ses);
	struct ev_shaper_t ev = {
		.ses = ses,
	};

	if (!pd)
		return;

	if (pd->rate) {
		ev.val = pd->rate;
		triton_event_fire(EV_SHAPER, &ev);
	}
}

static struct ipv4db_item_t *get_ip(struct ap_session *ses)
{
	struct cs_pd_t *pd;
	
	if (!conf_gw_ip_address && ses->ctrl->ppp)
		return NULL;

	pd = find_pd(ses);

	if (!pd)
		return NULL;

	if (!pd->ip.peer_addr)
		return NULL;

	if (!ses->ctrl->ppp)
		pd->ip.addr = 0;

	return &pd->ip;
}

static char* get_passwd(struct pwdb_t *pwdb, struct ap_session *ses, const char *username)
{
	struct cs_pd_t *pd = find_pd(ses);

#ifdef CRYPTO_OPENSSL
	if (conf_encrypted)
		return NULL;
#endif

	if (!pd)
		pd = create_pd(ses, username);
	
	if (!pd)
		return NULL;
	
	return _strdup(pd->passwd);
}

#ifdef CRYPTO_OPENSSL
static void des_encrypt(const uint8_t *input, const uint8_t *key, uint8_t *output)
{
	int i, j, parity;
	union
	{
		uint64_t u64;
		uint8_t buf[8];
	} p_key;
	DES_cblock cb;
	DES_cblock res;
	DES_key_schedule ks;

	memcpy(p_key.buf, key, 7);
	p_key.u64 = bswap_64(p_key.u64);

	for (i = 0; i < 8; i++) {
		cb[i] = (((p_key.u64 << (7 * i)) >> 56) & 0xfe);
		for( j = 0, parity = 0; j < 7; j++)
			if ((cb[i] >> (j + 1)) & 1)
				parity++;
		cb[i] |= (~parity) & 1;
	}

	DES_set_key_checked(&cb, &ks);
	memcpy(cb, input, 8);
	DES_ecb_encrypt(&cb, &res, &ks, DES_ENCRYPT);
	memcpy(output, res, 8);	
}

static int auth_pap(struct cs_pd_t *pd, const char *username, va_list args)
{
	const char *passwd = va_arg(args, const char *);
	MD4_CTX md4_ctx;
	unsigned char z_hash[21];
	char *u_passwd;
	int i, len = strlen(passwd);
	
	u_passwd = _malloc(len * 2);
	for (i = 0; i< len; i++) {
		u_passwd[i * 2] = passwd[i];
		u_passwd[i * 2 + 1] = 0;
	}

	memset(z_hash, 0, sizeof(z_hash));
	MD4_Init(&md4_ctx);
	MD4_Update(&md4_ctx, u_passwd, len * 2);
	MD4_Final(z_hash, &md4_ctx);

	_free(u_passwd);

	/*des_encrypt(ad->val, z_hash, nt_hash);
	des_encrypt(ad->val, z_hash + 7, nt_hash + 8);
	des_encrypt(ad->val, z_hash + 14, nt_hash + 16);*/
	
	if (memcmp(z_hash, pd->passwd, 16))
		return PWDB_DENIED;
	
	return PWDB_SUCCESS;
}

static int auth_chap_md5(struct cs_pd_t *pd, const char *username, va_list args)
{
	/*int id = va_arg(args, int);
	uint8_t *challenge = va_arg(args, uint8_t *);
	int challenge_len = va_arg(args, int);
	uint8_t *response = va_arg(args, uint8_t *);*/

	return PWDB_NO_IMPL;
}

static void derive_mppe_keys_mschap_v1(struct ap_session *ses, const uint8_t *z_hash, const uint8_t *challenge, int challenge_len)
{
	MD4_CTX md4_ctx;
	SHA_CTX sha_ctx;
	uint8_t digest[20];
	struct ppp_t *ppp = container_of(ses, typeof(*ppp), ses);

	struct ev_mppe_keys_t ev_mppe = {
		.ppp = ppp,
		.policy = -1,
		.recv_key = digest,
		.send_key = digest,
	};

	//NtPasswordHashHash
	MD4_Init(&md4_ctx);
	MD4_Update(&md4_ctx, z_hash, 16);
	MD4_Final(digest, &md4_ctx);

	//Get_Start_Key
	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, digest, 16);
	SHA1_Update(&sha_ctx, digest, 16);
	SHA1_Update(&sha_ctx, challenge, challenge_len);
	SHA1_Final(digest, &sha_ctx);	

	triton_event_fire(EV_MPPE_KEYS, &ev_mppe);
}

int auth_mschap_v1(struct ap_session *ses, struct cs_pd_t *pd, const char *username, va_list args)
{
	int id __unused = va_arg(args, int);
	const uint8_t *challenge = va_arg(args, const uint8_t *);
	int challenge_len = va_arg(args, int);
	const uint8_t *lm_response __unused = va_arg(args, const uint8_t *);
	const uint8_t *nt_response = va_arg(args, const uint8_t *);
	int flags __unused = va_arg(args, int);
	uint8_t z_hash[21];
	uint8_t nt_hash[24];

	memcpy(z_hash, pd->passwd, 16);
	memset(z_hash + 16, 0, sizeof(z_hash) - 16);
	
	des_encrypt(challenge, z_hash, nt_hash);
	des_encrypt(challenge, z_hash + 7, nt_hash + 8);
	des_encrypt(challenge, z_hash + 14, nt_hash + 16);

	if (memcmp(nt_hash, nt_response, 24))
		return PWDB_DENIED;

	if (ses->ctrl->ppp)
		derive_mppe_keys_mschap_v1(ses, z_hash, challenge, challenge_len);

	return PWDB_SUCCESS;
}

static void generate_mschap_response(const uint8_t *nt_response, const uint8_t *c_hash, const uint8_t *z_hash, char *authenticator)
{
	MD4_CTX md4_ctx;
	SHA_CTX sha_ctx;
	uint8_t pw_hash[MD4_DIGEST_LENGTH];
	uint8_t response[SHA_DIGEST_LENGTH];
	int i;
	
	uint8_t magic1[39] =
         {0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
          0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
          0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
          0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74};
	uint8_t magic2[41] =
         {0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
          0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
          0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
          0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
          0x6E};


	MD4_Init(&md4_ctx);
	MD4_Update(&md4_ctx, z_hash, 16);
	MD4_Final(pw_hash, &md4_ctx);

	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, pw_hash, 16);
	SHA1_Update(&sha_ctx, nt_response, 24);
	SHA1_Update(&sha_ctx, magic1, 39);
	SHA1_Final(response, &sha_ctx);

	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, response, 20);
	SHA1_Update(&sha_ctx, c_hash, 8);
	SHA1_Update(&sha_ctx, magic2, 41);
	SHA1_Final(response, &sha_ctx);
	
	for (i = 0; i < 20; i++)
		sprintf(authenticator + i*2, "%02X", response[i]);
}

static void derive_mppe_keys_mschap_v2(struct ap_session *ses, const uint8_t *z_hash, const uint8_t *nt_hash)
{
	struct ppp_t *ppp = container_of(ses, typeof(*ppp), ses);
	MD4_CTX md4_ctx;
	SHA_CTX sha_ctx;
	uint8_t digest[20];
	uint8_t send_key[20];
	uint8_t recv_key[20];
	
	uint8_t pad1[40] =
   {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

	uint8_t pad2[40] =
   {0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
    0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
    0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
    0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2};

	uint8_t magic1[27] =
   {0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
    0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
    0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79};

	uint8_t magic2[84] =
   {0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
    0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
    0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
    0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
    0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
    0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
    0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
    0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
    0x6b, 0x65, 0x79, 0x2e};

	uint8_t magic3[84] =
   {0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
    0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
    0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
    0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
    0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
    0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
    0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
    0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
    0x6b, 0x65, 0x79, 0x2e};

	struct ev_mppe_keys_t ev_mppe = {
		.ppp = ppp,
		.policy = -1,
		.recv_key = recv_key,
		.send_key = send_key,
	};
	
	//NtPasswordHashHash
	MD4_Init(&md4_ctx);
	MD4_Update(&md4_ctx, z_hash, 16);
	MD4_Final(digest, &md4_ctx);

	//GetMasterKey
	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, digest, 16);
	SHA1_Update(&sha_ctx, nt_hash, 24);
	SHA1_Update(&sha_ctx, magic1, sizeof(magic1));
	SHA1_Final(digest, &sha_ctx);

	//send key
	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, digest, 16);
	SHA1_Update(&sha_ctx, pad1, sizeof(pad1));
	SHA1_Update(&sha_ctx, magic3, sizeof(magic2));
	SHA1_Update(&sha_ctx, pad2, sizeof(pad2));
	SHA1_Final(send_key, &sha_ctx);

	//recv key
	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, digest, 16);
	SHA1_Update(&sha_ctx, pad1, sizeof(pad1));
	SHA1_Update(&sha_ctx, magic2, sizeof(magic3));
	SHA1_Update(&sha_ctx, pad2, sizeof(pad2));
	SHA1_Final(recv_key, &sha_ctx);

	triton_event_fire(EV_MPPE_KEYS, &ev_mppe);
}

int auth_mschap_v2(struct ap_session *ses, struct cs_pd_t *pd, const char *username, va_list args)
{
	int id __unused = va_arg(args, int);
	const uint8_t *challenge = va_arg(args, const uint8_t *);
	const uint8_t *peer_challenge = va_arg(args, const uint8_t *);
	const uint8_t *reserved __unused = va_arg(args, const uint8_t *);
	const uint8_t *response = va_arg(args, const uint8_t *);
	int flags __unused = va_arg(args, int);
	char *authenticator = va_arg(args, char *);
	uint8_t z_hash[21];
	uint8_t nt_hash[24];
	uint8_t c_hash[SHA_DIGEST_LENGTH];
	SHA_CTX sha_ctx;

	SHA1_Init(&sha_ctx);
	SHA1_Update(&sha_ctx, peer_challenge, 16);
	SHA1_Update(&sha_ctx, challenge, 16);
	SHA1_Update(&sha_ctx, username, strlen(username));
	SHA1_Final(c_hash, &sha_ctx);

	memcpy(z_hash, pd->passwd, 16);
	memset(z_hash + 16, 0, sizeof(z_hash) - 16);
	
	des_encrypt(c_hash, z_hash, nt_hash);
	des_encrypt(c_hash, z_hash + 7, nt_hash + 8);
	des_encrypt(c_hash, z_hash + 14, nt_hash + 16);

	if (memcmp(nt_hash, response, 24))
		return PWDB_DENIED;

	if (ses->ctrl->ppp)
		derive_mppe_keys_mschap_v2(ses, z_hash, response);

	generate_mschap_response(response, c_hash, z_hash, authenticator);	

	return PWDB_SUCCESS;
}

static int check_passwd(struct pwdb_t *pwdb, struct ap_session *ses, const char *username, int type, va_list _args)
{
	va_list args;
	int r = PWDB_NO_IMPL;
	struct cs_pd_t *pd;

	if (!conf_encrypted)
		return PWDB_NO_IMPL;
	
	pd = find_pd(ses);

	if (!pd)
		pd = create_pd(ses, username);

	if (!pd)
		return PWDB_NO_IMPL;
	
	va_copy(args, _args);

	switch (type) {
		case PPP_PAP:
			r = auth_pap(pd, username, args);
			break;
		case PPP_CHAP:
			type = va_arg(args, int);
			switch (type) {
				case CHAP_MD5:
					r = auth_chap_md5(pd, username, args);
					break;
				case MSCHAP_V1:
					r = auth_mschap_v1(ses, pd, username, args);
					break;
				case MSCHAP_V2:
					r = auth_mschap_v2(ses, pd, username, args);
					break;
			}
			break;
	}
	
	va_end(args);

	return r;
}
#endif

static struct ipdb_t ipdb = {
	.get_ipv4 = get_ip,
};

static struct pwdb_t pwdb = {
	.get_passwd = get_passwd,
#ifdef CRYPTO_OPENSSL
	.check = check_passwd,
#endif
};

#ifdef CRYPTO_OPENSSL
static void clear_hash_chain(void)
{
	struct hash_chain *hc;

	while (!list_empty(&hash_chain)) {
		hc = list_entry(hash_chain.next, typeof(*hc), entry);
		list_del(&hc->entry);
		_free(hc);
	}
}

static void parse_hash_chain(const char *opt)
{
	char *str = _strdup(opt);
	char *ptr1 = str, *ptr2;
	struct hash_chain *hc;
	int f = 0;
	
	while (!f) {
		for (ptr2 = ptr1 + 1; *ptr2 && *ptr2 != ','; ptr2++);
		f = *ptr2 == 0;
		*ptr2 = 0;
		hc = _malloc(sizeof(*hc));
		hc->md = EVP_get_digestbyname(ptr1);
		if (!hc->md) {
			log_error("chap-secrets: digest '%s' is unavailable\n", ptr1);
			_free(hc);
			return;
		}
		list_add_tail(&hc->entry, &hash_chain);
		ptr1 = ptr2 + 1;
	}
}
#endif

static void parse_gw_ip_address(const char *opt)
{
	char addr[17];
	const char *ptr = strchr(opt, '/');

	if (ptr) {
		memcpy(addr, opt, ptr - opt);
		addr[ptr - opt] = 0;
		conf_gw_ip_address = inet_addr(addr);
		conf_netmask = atoi(ptr + 1);
		if (conf_netmask < 0 || conf_netmask > 32) {
			log_error("chap-secrets: invalid netmask %i\n", conf_netmask);
			conf_netmask = 32;
		}
	} else {
		conf_gw_ip_address = inet_addr(opt);
		conf_netmask = 32;
	}
}

static void load_config(void)
{
	const char *opt;

	if (conf_chap_secrets && conf_chap_secrets != def_chap_secrets)
		_free(conf_chap_secrets);
	opt = conf_get_opt("chap-secrets", "chap-secrets");
	if (opt)
		conf_chap_secrets = _strdup(opt);
	else
		conf_chap_secrets = def_chap_secrets;

	opt = conf_get_opt("chap-secrets", "gw-ip-address");
	if (opt)
		parse_gw_ip_address(opt);
	else {
		conf_gw_ip_address = 0;
	}
	
	opt = conf_get_opt("chap-secrets", "encrypted");
	if (opt)
		conf_encrypted = atoi(opt);
	else
		conf_encrypted = 0;
	
#ifdef CRYPTO_OPENSSL
	clear_hash_chain();
	opt = conf_get_opt("chap-secrets", "username-hash");
	if (opt)
		parse_hash_chain(opt);
#endif
}

static void init(void)
{
	load_config();

	pwdb_register(&pwdb);
	ipdb_register(&ipdb);
	
	triton_event_register_handler(EV_SES_FINISHED, (triton_event_func)ev_ses_finished);
	triton_event_register_handler(EV_SES_PRE_UP, (triton_event_func)ev_ses_pre_up);
	triton_event_register_handler(EV_CONFIG_RELOAD, (triton_event_func)load_config);
}

DEFINE_INIT(51, init);