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
|
/*
* ppp_mppe.c - interface MPPE to the PPP code.
* This version is for use with Linux kernel 2.6.14+
*
* By Frank Cusack <fcusack@fcusack.com>.
* Copyright (c) 2002,2003,2004 Google, Inc.
* All rights reserved.
*
* License:
* Permission to use, copy, modify, and distribute this software and its
* documentation is hereby granted, provided that the above copyright
* notice appears in all copies. This software is provided without any
* warranty, express or implied.
*
* ALTERNATIVELY, provided that this notice is retained in full, this product
* may be distributed under the terms of the GNU General Public License (GPL),
* in which case the provisions of the GPL apply INSTEAD OF those given above.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*
* Changelog:
* 08/12/05 - Matt Domsch <Matt_Domsch@dell.com>
* Only need extra skb padding on transmit, not receive.
* 06/18/04 - Matt Domsch <Matt_Domsch@dell.com>, Oleg Makarenko <mole@quadra.ru>
* Use Linux kernel 2.6 arc4 and sha1 routines rather than
* providing our own.
* 2/15/04 - TS: added #include <version.h> and testing for Kernel
* version before using
* MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are
* deprecated in 2.6
*/
#include <crypto/arc4.h>
#include <crypto/hash.h>
#include <linux/err.h>
#include <linux/fips.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/ppp_defs.h>
#include <linux/ppp-comp.h>
#include <linux/scatterlist.h>
#include <asm/unaligned.h>
#include "ppp_mppe.h"
MODULE_AUTHOR("Frank Cusack <fcusack@fcusack.com>");
MODULE_DESCRIPTION("Point-to-Point Protocol Microsoft Point-to-Point Encryption support");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS("ppp-compress-" __stringify(CI_MPPE));
MODULE_VERSION("1.0.2");
#define SHA1_PAD_SIZE 40
/*
* kernel crypto API needs its arguments to be in kmalloc'd memory, not in the module
* static data area. That means sha_pad needs to be kmalloc'd.
*/
struct sha_pad {
unsigned char sha_pad1[SHA1_PAD_SIZE];
unsigned char sha_pad2[SHA1_PAD_SIZE];
};
static struct sha_pad *sha_pad;
static inline void sha_pad_init(struct sha_pad *shapad)
{
memset(shapad->sha_pad1, 0x00, sizeof(shapad->sha_pad1));
memset(shapad->sha_pad2, 0xF2, sizeof(shapad->sha_pad2));
}
/*
* State for an MPPE (de)compressor.
*/
struct ppp_mppe_state {
struct arc4_ctx arc4;
struct shash_desc *sha1;
unsigned char *sha1_digest;
unsigned char master_key[MPPE_MAX_KEY_LEN];
unsigned char session_key[MPPE_MAX_KEY_LEN];
unsigned keylen; /* key length in bytes */
/* NB: 128-bit == 16, 40-bit == 8! */
/* If we want to support 56-bit, */
/* the unit has to change to bits */
unsigned char bits; /* MPPE control bits */
unsigned ccount; /* 12-bit coherency count (seqno) */
unsigned stateful; /* stateful mode flag */
int discard; /* stateful mode packet loss flag */
int sanity_errors; /* take down LCP if too many */
int unit;
int debug;
struct compstat stats;
};
/* struct ppp_mppe_state.bits definitions */
#define MPPE_BIT_A 0x80 /* Encryption table were (re)inititalized */
#define MPPE_BIT_B 0x40 /* MPPC only (not implemented) */
#define MPPE_BIT_C 0x20 /* MPPC only (not implemented) */
#define MPPE_BIT_D 0x10 /* This is an encrypted frame */
#define MPPE_BIT_FLUSHED MPPE_BIT_A
#define MPPE_BIT_ENCRYPTED MPPE_BIT_D
#define MPPE_BITS(p) ((p)[4] & 0xf0)
#define MPPE_CCOUNT(p) ((((p)[4] & 0x0f) << 8) + (p)[5])
#define MPPE_CCOUNT_SPACE 0x1000 /* The size of the ccount space */
#define MPPE_OVHD 2 /* MPPE overhead/packet */
#define SANITY_MAX 1600 /* Max bogon factor we will tolerate */
/*
* Key Derivation, from RFC 3078, RFC 3079.
* Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
*/
static void get_new_key_from_sha(struct ppp_mppe_state * state)
{
crypto_shash_init(state->sha1);
crypto_shash_update(state->sha1, state->master_key,
state->keylen);
crypto_shash_update(state->sha1, sha_pad->sha_pad1,
sizeof(sha_pad->sha_pad1));
crypto_shash_update(state->sha1, state->session_key,
state->keylen);
crypto_shash_update(state->sha1, sha_pad->sha_pad2,
sizeof(sha_pad->sha_pad2));
crypto_shash_final(state->sha1, state->sha1_digest);
}
/*
* Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3.
* Well, not what's written there, but rather what they meant.
*/
static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
{
get_new_key_from_sha(state);
if (!initial_key) {
arc4_setkey(&state->arc4, state->sha1_digest, state->keylen);
arc4_crypt(&state->arc4, state->session_key, state->sha1_digest,
state->keylen);
} else {
memcpy(state->session_key, state->sha1_digest, state->keylen);
}
if (state->keylen == 8) {
/* See RFC 3078 */
state->session_key[0] = 0xd1;
state->session_key[1] = 0x26;
state->session_key[2] = 0x9e;
}
arc4_setkey(&state->arc4, state->session_key, state->keylen);
}
/*
* Allocate space for a (de)compressor.
*/
static void *mppe_alloc(unsigned char *options, int optlen)
{
struct ppp_mppe_state *state;
struct crypto_shash *shash;
unsigned int digestsize;
if (optlen != CILEN_MPPE + sizeof(state->master_key) ||
options[0] != CI_MPPE || options[1] != CILEN_MPPE ||
fips_enabled)
goto out;
state = kzalloc(sizeof(*state), GFP_KERNEL);
if (state == NULL)
goto out;
shash = crypto_alloc_shash("sha1", 0, 0);
if (IS_ERR(shash))
goto out_free;
state->sha1 = kmalloc(sizeof(*state->sha1) +
crypto_shash_descsize(shash),
GFP_KERNEL);
if (!state->sha1) {
crypto_free_shash(shash);
goto out_free;
}
state->sha1->tfm = shash;
digestsize = crypto_shash_digestsize(shash);
if (digestsize < MPPE_MAX_KEY_LEN)
goto out_free;
state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
if (!state->sha1_digest)
goto out_free;
/* Save keys. */
memcpy(state->master_key, &options[CILEN_MPPE],
sizeof(state->master_key));
memcpy(state->session_key, state->master_key,
sizeof(state->master_key));
/*
* We defer initial key generation until mppe_init(), as mppe_alloc()
* is called frequently during negotiation.
*/
return (void *)state;
out_free:
kfree(state->sha1_digest);
if (state->sha1) {
crypto_free_shash(state->sha1->tfm);
kfree_sensitive(state->sha1);
}
kfree(state);
out:
return NULL;
}
/*
* Deallocate space for a (de)compressor.
*/
static void mppe_free(void *arg)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
if (state) {
kfree(state->sha1_digest);
crypto_free_shash(state->sha1->tfm);
kfree_sensitive(state->sha1);
kfree_sensitive(state);
}
}
/*
* Initialize (de)compressor state.
*/
static int
mppe_init(void *arg, unsigned char *options, int optlen,
|