1
2/*
3 * ng_mppc.c
4 *
5 * Copyright (c) 1996-2000 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 * copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 * Communications, Inc. trademarks, including the mark "WHISTLE
16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 * such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Author: Archie Cobbs <archie@freebsd.org>
38 *
39 * $Whistle: ng_mppc.c,v 1.4 1999/11/25 00:10:12 archie Exp $
40 * $FreeBSD: head/sys/netgraph/ng_mppc.c 68876 2000-11-18 15:17:43Z dwmalone $
41 */
42
43/*
44 * Microsoft PPP compression (MPPC) and encryption (MPPE) netgraph node type.
45 *
46 * You must define one or both of the NETGRAPH_MPPC_COMPRESSION and/or
47 * NETGRAPH_MPPC_ENCRYPTION options for this node type to be useful.
48 */
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/kernel.h>
53#include <sys/mbuf.h>
54#include <sys/malloc.h>
55#include <sys/errno.h>
56#include <sys/syslog.h>
57
58#include <netgraph/ng_message.h>
59#include <netgraph/netgraph.h>
60#include <netgraph/ng_mppc.h>
61
62#include "opt_netgraph.h"
63
64#if !defined(NETGRAPH_MPPC_COMPRESSION) && !defined(NETGRAPH_MPPC_ENCRYPTION)
65#error Need either NETGRAPH_MPPC_COMPRESSION or NETGRAPH_MPPC_ENCRYPTION
66#endif
67
68#ifdef NETGRAPH_MPPC_COMPRESSION
69/* XXX this file doesn't exist yet, but hopefully someday it will... */
70#include <net/mppc.h>
71#endif
72#ifdef NETGRAPH_MPPC_ENCRYPTION
73#include <crypto/rc4/rc4.h>
74#endif
75#include <crypto/sha1.h>
76
77/* Decompression blowup */
78#define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */
79#define MPPC_DECOMP_SAFETY 100 /* plus this much margin */
80
81/* MPPC/MPPE header length */
82#define MPPC_HDRLEN 2
83
84/* Key length */
85#define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8)
86
87/* What sequence number jump is too far */
88#define MPPC_INSANE_JUMP 256
89
90/* MPPC packet header bits */
91#define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */
92#define MPPC_FLAG_RESTART 0x4000 /* compress history restart */
93#define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */
94#define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */
95#define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */
96
97#define MPPE_UPDATE_MASK 0xff /* coherency count when we're */
98#define MPPE_UPDATE_FLAG 0xff /* supposed to update key */
99
100#define MPPC_COMP_OK 0x05
101#define MPPC_DECOMP_OK 0x05
102
103/* Per direction info */
104struct ng_mppc_dir {
105 struct ng_mppc_config cfg; /* configuration */
106 hook_p hook; /* netgraph hook */
107 u_int16_t cc:12; /* coherency count */
108 u_char flushed; /* clean history (xmit only) */
109#ifdef NETGRAPH_MPPC_COMPRESSION
110 u_char *history; /* compression history */
111#endif
112#ifdef NETGRAPH_MPPC_ENCRYPTION
113 u_char key[MPPE_KEY_LEN]; /* session key */
114 struct rc4_state rc4; /* rc4 state */
115#endif
116};
117
118/* Node private data */
119struct ng_mppc_private {
120 struct ng_mppc_dir xmit; /* compress/encrypt config */
121 struct ng_mppc_dir recv; /* decompress/decrypt config */
122 char *ctrlpath; /* path to controlling node */
123};
124typedef struct ng_mppc_private *priv_p;
125
126/* Netgraph node methods */
127static ng_constructor_t ng_mppc_constructor;
128static ng_rcvmsg_t ng_mppc_rcvmsg;
129static ng_shutdown_t ng_mppc_rmnode;
130static ng_newhook_t ng_mppc_newhook;
131static ng_rcvdata_t ng_mppc_rcvdata;
132static ng_disconnect_t ng_mppc_disconnect;
133
134/* Helper functions */
135static int ng_mppc_compress(node_p node,
136 struct mbuf *m, struct mbuf **resultp);
137static int ng_mppc_decompress(node_p node,
138 struct mbuf *m, struct mbuf **resultp);
139static void ng_mppc_getkey(const u_char *h, u_char *h2, int len);
140static void ng_mppc_updatekey(u_int32_t bits,
141 u_char *key0, u_char *key, struct rc4_state *rc4);
142static void ng_mppc_reset_req(node_p node);
143
144/* Node type descriptor */
145static struct ng_type ng_mppc_typestruct = {
146 NG_VERSION,
147 NG_MPPC_NODE_TYPE,
148 NULL,
149 ng_mppc_constructor,
150 ng_mppc_rcvmsg,
151 ng_mppc_rmnode,
152 ng_mppc_newhook,
153 NULL,
154 NULL,
155 ng_mppc_rcvdata,
156 ng_mppc_rcvdata,
157 ng_mppc_disconnect,
158 NULL
159};
160NETGRAPH_INIT(mppc, &ng_mppc_typestruct);
161
162/* Fixed bit pattern to weaken keysize down to 40 bits */
163static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e };
164
165#define ERROUT(x) do { error = (x); goto done; } while (0)
166
167/************************************************************************
168 NETGRAPH NODE STUFF
169 ************************************************************************/
170
171/*
172 * Node type constructor
173 */
174static int
175ng_mppc_constructor(node_p *nodep)
176{
177 priv_p priv;
178 int error;
179
180 /* Allocate private structure */
181 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
182 if (priv == NULL)
183 return (ENOMEM);
184
185 /* Call generic node constructor */
186 if ((error = ng_make_node_common(&ng_mppc_typestruct, nodep))) {
187 FREE(priv, M_NETGRAPH);
188 return (error);
189 }
190 (*nodep)->private = priv;
191
192 /* Done */
193 return (0);
194}
195
196/*
197 * Give our OK for a hook to be added
198 */
199static int
200ng_mppc_newhook(node_p node, hook_p hook, const char *name)
201{
202 const priv_p priv = node->private;
203 hook_p *hookPtr;
204
205 /* Check hook name */
206 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0)
207 hookPtr = &priv->xmit.hook;
208 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0)
209 hookPtr = &priv->recv.hook;
210 else
211 return (EINVAL);
212
213 /* See if already connected */
214 if (*hookPtr != NULL)
215 return (EISCONN);
216
217 /* OK */
218 *hookPtr = hook;
219 return (0);
220}
221
222/*
223 * Receive a control message
224 */
225static int
226ng_mppc_rcvmsg(node_p node, struct ng_mesg *msg,
227 const char *raddr, struct ng_mesg **rptr, hook_p lasthook)
228{
229 const priv_p priv = node->private;
230 struct ng_mesg *resp = NULL;
231 int error = 0;
232
233 switch (msg->header.typecookie) {
234 case NGM_MPPC_COOKIE:
235 switch (msg->header.cmd) {
236 case NGM_MPPC_CONFIG_COMP:
237 case NGM_MPPC_CONFIG_DECOMP:
238 {
239 struct ng_mppc_config *const cfg
240 = (struct ng_mppc_config *)msg->data;
241 const int isComp =
242 msg->header.cmd == NGM_MPPC_CONFIG_COMP;
243 struct ng_mppc_dir *const d = isComp ?
244 &priv->xmit : &priv->recv;
245
246 /* Check configuration */
247 if (msg->header.arglen != sizeof(*cfg))
248 ERROUT(EINVAL);
249 if (cfg->enable) {
250 if ((cfg->bits & ~MPPC_VALID_BITS) != 0)
251 ERROUT(EINVAL);
252#ifndef NETGRAPH_MPPC_COMPRESSION
253 if ((cfg->bits & MPPC_BIT) != 0)
254 ERROUT(EPROTONOSUPPORT);
255#endif
256#ifndef NETGRAPH_MPPC_ENCRYPTION
257 if ((cfg->bits & MPPE_BITS) != 0)
258 ERROUT(EPROTONOSUPPORT);
259#endif
260 } else
261 cfg->bits = 0;
262
263 /* Save return address so we can send reset-req's */
264 if (priv->ctrlpath != NULL) {
265 FREE(priv->ctrlpath, M_NETGRAPH);
266 priv->ctrlpath = NULL;
267 }
268 if (!isComp && raddr != NULL) {
269 MALLOC(priv->ctrlpath, char *,
270 strlen(raddr) + 1, M_NETGRAPH, M_NOWAIT);
271 if (priv->ctrlpath == NULL)
272 ERROUT(ENOMEM);
273 strcpy(priv->ctrlpath, raddr);
274 }
275
276 /* Configuration is OK, reset to it */
277 d->cfg = *cfg;
278
279#ifdef NETGRAPH_MPPC_COMPRESSION
280 /* Initialize state buffers for compression */
281 if (d->history != NULL) {
282 FREE(d->history, M_NETGRAPH);
283 d->history = NULL;
284 }
285 if ((cfg->bits & MPPC_BIT) != 0) {
286 MALLOC(d->history, u_char *,
287 isComp ? MPPC_SizeOfCompressionHistory() :
288 MPPC_SizeOfDecompressionHistory(),
289 M_NETGRAPH, M_NOWAIT);
290 if (d->history == NULL)
291 ERROUT(ENOMEM);
292 if (isComp)
293 MPPC_InitCompressionHistory(d->history);
294 else {
295 MPPC_InitDecompressionHistory(
296 d->history);
297 }
298 }
299#endif
300
301#ifdef NETGRAPH_MPPC_ENCRYPTION
302 /* Generate initial session keys for encryption */
303 if ((cfg->bits & MPPE_BITS) != 0) {
304 const int keylen = KEYLEN(cfg->bits);
305
306 bcopy(cfg->startkey, d->key, keylen);
307 ng_mppc_getkey(cfg->startkey, d->key, keylen);
308 if ((cfg->bits & MPPE_128) == 0) {
309 bcopy(&ng_mppe_weakenkey, d->key,
310 sizeof(ng_mppe_weakenkey));
311 }
312 rc4_init(&d->rc4, d->key, keylen);
313 }
314#endif
315
316 /* Initialize other state */
317 d->cc = 0;
318 d->flushed = 0;
319 break;
320 }
321
322 case NGM_MPPC_RESETREQ:
323 ng_mppc_reset_req(node);
324 break;
325
326 default:
327 error = EINVAL;
328 break;
329 }
330 break;
331 default:
332 error = EINVAL;
333 break;
334 }
335 if (rptr)
336 *rptr = resp;
337 else if (resp)
338 FREE(resp, M_NETGRAPH);
339
340done:
341 FREE(msg, M_NETGRAPH);
342 return (error);
343}
344
345/*
346 * Receive incoming data on our hook.
347 */
348static int
349ng_mppc_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
350 struct mbuf **ret_m, meta_p *ret_meta)
351{
352 const node_p node = hook->node;
353 const priv_p priv = node->private;
354 struct mbuf *out;
355 int error;
356
357 /* Compress and/or encrypt */
358 if (hook == priv->xmit.hook) {
359 if (!priv->xmit.cfg.enable) {
360 NG_FREE_DATA(m, meta);
361 return (ENXIO);
362 }
363 if ((error = ng_mppc_compress(node, m, &out)) != 0) {
364 NG_FREE_DATA(m, meta);
365 return(error);
366 }
367 m_freem(m);
368 NG_SEND_DATA(error, priv->xmit.hook, out, meta);
369 return (error);
370 }
371
372 /* Decompress and/or decrypt */
373 if (hook == priv->recv.hook) {
374 if (!priv->recv.cfg.enable) {
375 NG_FREE_DATA(m, meta);
376 return (ENXIO);
377 }
378 if ((error = ng_mppc_decompress(node, m, &out)) != 0) {
379 NG_FREE_DATA(m, meta);
380 if (error == EINVAL && priv->ctrlpath != NULL) {
381 struct ng_mesg *msg;
382
383 /* Need to send a reset-request */
384 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE,
385 NGM_MPPC_RESETREQ, 0, M_NOWAIT);
386 if (msg == NULL)
387 return (error);
388 ng_send_msg(node, msg, priv->ctrlpath, NULL);
389 }
390 return (error);
391 }
392 m_freem(m);
393 NG_SEND_DATA(error, priv->recv.hook, out, meta);
394 return (error);
395 }
396
397 /* Oops */
398 panic("%s: unknown hook", __FUNCTION__);
399}
400
401/*
402 * Destroy node
403 */
404static int
405ng_mppc_rmnode(node_p node)
406{
407 const priv_p priv = node->private;
408
409 /* Take down netgraph node */
410 node->flags |= NG_INVALID;
411 ng_cutlinks(node);
412 ng_unname(node);
413 if (priv->ctrlpath != NULL)
414 FREE(priv->ctrlpath, M_NETGRAPH);
415#ifdef NETGRAPH_MPPC_COMPRESSION
416 if (priv->xmit.history != NULL)
417 FREE(priv->xmit.history, M_NETGRAPH);
418 if (priv->recv.history != NULL)
419 FREE(priv->recv.history, M_NETGRAPH);
420#endif
421 bzero(priv, sizeof(*priv));
422 FREE(priv, M_NETGRAPH);
423 node->private = NULL;
424 ng_unref(node); /* let the node escape */
425 return (0);
426}
427
428/*
429 * Hook disconnection
430 */
431static int
432ng_mppc_disconnect(hook_p hook)
433{
434 const node_p node = hook->node;
435 const priv_p priv = node->private;
436
437 /* Zero out hook pointer */
438 if (hook == priv->xmit.hook)
439 priv->xmit.hook = NULL;
440 if (hook == priv->recv.hook)
441 priv->recv.hook = NULL;
442
443 /* Go away if no longer connected */
444 if (node->numhooks == 0)
445 ng_rmnode(node);
446 return (0);
447}
448
449/************************************************************************
450 HELPER STUFF
451 ************************************************************************/
452
453/*
454 * Compress/encrypt a packet and put the result in a new mbuf at *resultp.
455 * The original mbuf is not free'd.
456 */
457static int
458ng_mppc_compress(node_p node, struct mbuf *m, struct mbuf **resultp)
459{
460 const priv_p priv = node->private;
461 struct ng_mppc_dir *const d = &priv->xmit;
462 u_char *inbuf, *outbuf;
463 int outlen, inlen;
464 u_int16_t header;
465
466 /* Initialize */
467 *resultp = NULL;
468 header = d->cc;
469 if (d->flushed) {
470 header |= MPPC_FLAG_FLUSHED;
471 d->flushed = 0;
472 }
473
474 /* Work with contiguous regions of memory */
475 inlen = m->m_pkthdr.len;
476 MALLOC(inbuf, u_char *, inlen, M_NETGRAPH, M_NOWAIT);
477 if (inbuf == NULL)
478 return (ENOMEM);
479 m_copydata(m, 0, inlen, (caddr_t)inbuf);
480 if ((d->cfg.bits & MPPC_BIT) != 0)
481 outlen = MPPC_MAX_BLOWUP(inlen);
482 else
483 outlen = MPPC_HDRLEN + inlen;
484 MALLOC(outbuf, u_char *, outlen, M_NETGRAPH, M_NOWAIT);
485 if (outbuf == NULL) {
486 FREE(inbuf, M_NETGRAPH);
487 return (ENOMEM);
488 }
489
490 /* Compress "inbuf" into "outbuf" (if compression enabled) */
491#ifdef NETGRAPH_MPPC_COMPRESSION
492 if ((d->cfg.bits & MPPC_BIT) != 0) {
493 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS;
494 u_char *source, *dest;
495 u_long sourceCnt, destCnt;
496 int rtn;
497
498 /* Prepare to compress */
499 source = inbuf;
500 sourceCnt = inlen;
501 dest = outbuf + MPPC_HDRLEN;
502 destCnt = outlen - MPPC_HDRLEN;
503 if ((d->cfg.bits & MPPE_STATELESS) == 0)
504 flags |= MPPC_SAVE_HISTORY;
505
506 /* Compress */
507 rtn = MPPC_Compress(&source, &dest, &sourceCnt,
508 &destCnt, d->history, flags, 0);
509
510 /* Check return value */
511 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__));
512 if ((rtn & MPPC_EXPANDED) == 0
513 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) {
514 outlen -= destCnt;
515 header |= MPPC_FLAG_COMPRESSED;
516 if ((rtn & MPPC_RESTART_HISTORY) != 0)
517 header |= MPPC_FLAG_RESTART;
518 }
519 d->flushed = (rtn & MPPC_EXPANDED) != 0
520 || (flags & MPPC_SAVE_HISTORY) == 0;
521 }
522#endif
523
524 /* If we did not compress this packet, copy it to output buffer */
525 if ((header & MPPC_FLAG_COMPRESSED) == 0) {
526 bcopy(inbuf, outbuf + MPPC_HDRLEN, inlen);
527 outlen = MPPC_HDRLEN + inlen;
528 }
529 FREE(inbuf, M_NETGRAPH);
530
531 /* Always set the flushed bit in stateless mode */
532 if ((d->cfg.bits & MPPE_STATELESS) != 0)
533 header |= MPPC_FLAG_FLUSHED;
534
535 /* Now encrypt packet (if encryption enabled) */
536#ifdef NETGRAPH_MPPC_ENCRYPTION
537 if ((d->cfg.bits & MPPE_BITS) != 0) {
538
539 /* Set header bits; need to reset key if we say we did */
540 header |= MPPC_FLAG_ENCRYPTED;
541 if ((header & MPPC_FLAG_FLUSHED) != 0)
542 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
543
544 /* Update key if it's time */
545 if ((d->cfg.bits & MPPE_STATELESS) != 0
546 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) {
547 ng_mppc_updatekey(d->cfg.bits,
548 d->cfg.startkey, d->key, &d->rc4);
549 }
550
551 /* Encrypt packet */
552 rc4_crypt(&d->rc4, outbuf + MPPC_HDRLEN,
553 outbuf + MPPC_HDRLEN, outlen - MPPC_HDRLEN);
554 }
555#endif
556
557 /* Update sequence number */
558 d->cc++;
559
560 /* Install header */
561 *((u_int16_t *)outbuf) = htons(header);
562
563 /* Return packet in an mbuf */
564 *resultp = m_devget((caddr_t)outbuf, outlen, 0, NULL, NULL);
565 FREE(outbuf, M_NETGRAPH);
566 return (*resultp == NULL ? ENOBUFS : 0);
567}
568
569/*
570 * Decompress/decrypt packet and put the result in a new mbuf at *resultp.
571 * The original mbuf is not free'd.
572 */
573static int
574ng_mppc_decompress(node_p node, struct mbuf *m, struct mbuf **resultp)
575{
576 const priv_p priv = node->private;
577 struct ng_mppc_dir *const d = &priv->recv;
578 u_int16_t header, cc, numLost;
579 u_char *buf;
580 int len;
581
582 /* Pull off header */
583 if (m->m_pkthdr.len < MPPC_HDRLEN)
584 return (EINVAL);
585 m_copydata(m, 0, MPPC_HDRLEN, (caddr_t)&header);
586 NTOHS(header);
587 cc = (header & MPPC_CCOUNT_MASK);
588
589 /* Copy payload into a contiguous region of memory */
590 len = m->m_pkthdr.len - MPPC_HDRLEN;
591 MALLOC(buf, u_char *, len, M_NETGRAPH, M_NOWAIT);
592 if (buf == NULL)
593 return (ENOMEM);
594 m_copydata(m, MPPC_HDRLEN, len, (caddr_t)buf);
595
596 /* Check for insane jumps in sequence numbering (D.O.S. attack) */
597 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK);
598 if (numLost >= MPPC_INSANE_JUMP) {
599 log(LOG_ERR, "%s: insane jump %d", __FUNCTION__, numLost);
600 priv->recv.cfg.enable = 0;
601 goto failed;
602 }
603
604 /* If flushed bit set, we can always handle packet */
605 if ((header & MPPC_FLAG_FLUSHED) != 0) {
606#ifdef NETGRAPH_MPPC_COMPRESSION
607 if (d->history != NULL)
608 MPPC_InitDecompressionHistory(d->history);
609#endif
610#ifdef NETGRAPH_MPPC_ENCRYPTION
611 if ((d->cfg.bits & MPPE_BITS) != 0) {
612
613 /* Resync as necessary, skipping lost packets */
614 while (d->cc != cc) {
615 if ((d->cfg.bits & MPPE_STATELESS)
616 || (d->cc & MPPE_UPDATE_MASK)
617 == MPPE_UPDATE_FLAG) {
618 ng_mppc_updatekey(d->cfg.bits,
619 d->cfg.startkey, d->key, &d->rc4);
620 }
621 d->cc++;
622 }
623
624 /* Reset key (except in stateless mode, see below) */
625 if ((d->cfg.bits & MPPE_STATELESS) == 0)
626 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
627 }
628#endif
629 d->cc = cc; /* skip over lost seq numbers */
630 numLost = 0; /* act like no packets were lost */
631 }
632
633 /* Can't decode non-sequential packets without a flushed bit */
634 if (numLost != 0)
635 goto failed;
636
637 /* Decrypt packet */
638 if ((header & MPPC_FLAG_ENCRYPTED) != 0) {
639
640 /* Are we not expecting encryption? */
641 if ((d->cfg.bits & MPPE_BITS) == 0) {
642 log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
643 __FUNCTION__, "encrypted");
644 goto failed;
645 }
646
647#ifdef NETGRAPH_MPPC_ENCRYPTION
648 /* Update key if it's time (always in stateless mode) */
649 if ((d->cfg.bits & MPPE_STATELESS) != 0
650 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) {
651 ng_mppc_updatekey(d->cfg.bits,
652 d->cfg.startkey, d->key, &d->rc4);
653 }
654
655 /* Decrypt packet */
656 rc4_crypt(&d->rc4, buf, buf, len);
657#endif
658 } else {
659
660 /* Are we expecting encryption? */
661 if ((d->cfg.bits & MPPE_BITS) != 0) {
662 log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
663 __FUNCTION__, "unencrypted");
664 goto failed;
665 }
666 }
667
668 /* Update coherency count for next time (12 bit arithmetic) */
669 d->cc++;
670
671 /* Check for unexpected compressed packet */
672 if ((header & MPPC_FLAG_COMPRESSED) != 0
673 && (d->cfg.bits & MPPC_BIT) == 0) {
674 log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
675 __FUNCTION__, "compressed");
676failed:
677 FREE(buf, M_NETGRAPH);
678 return (EINVAL);
679 }
680
681#ifdef NETGRAPH_MPPC_COMPRESSION
682 /* Decompress packet */
683 if ((header & MPPC_FLAG_COMPRESSED) != 0) {
684 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS;
685 u_char *decompbuf, *source, *dest;
686 u_long sourceCnt, destCnt;
687 int decomplen, rtn;
688
689 /* Allocate a buffer for decompressed data */
690 MALLOC(decompbuf, u_char *, MPPC_DECOMP_BUFSIZE
691 + MPPC_DECOMP_SAFETY, M_NETGRAPH, M_NOWAIT);
692 if (decompbuf == NULL) {
693 FREE(buf, M_NETGRAPH);
694 return (ENOMEM);
695 }
696 decomplen = MPPC_DECOMP_BUFSIZE;
697
698 /* Prepare to decompress */
699 source = buf;
700 sourceCnt = len;
701 dest = decompbuf;
702 destCnt = decomplen;
703 if ((header & MPPC_FLAG_RESTART) != 0)
704 flags |= MPPC_RESTART_HISTORY;
705
706 /* Decompress */
707 rtn = MPPC_Decompress(&source, &dest,
708 &sourceCnt, &destCnt, d->history, flags);
709
710 /* Check return value */
711 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__));
712 if ((rtn & MPPC_DEST_EXHAUSTED) != 0
713 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) {
714 log(LOG_ERR, "%s: decomp returned 0x%x",
715 __FUNCTION__, rtn);
716 FREE(decompbuf, M_NETGRAPH);
717 goto failed;
718 }
719
720 /* Replace compressed data with decompressed data */
721 FREE(buf, M_NETGRAPH);
722 buf = decompbuf;
723 len = decomplen - destCnt;
724 }
725#endif
726
727 /* Return result in an mbuf */
728 *resultp = m_devget((caddr_t)buf, len, 0, NULL, NULL);
729 FREE(buf, M_NETGRAPH);
730 return (*resultp == NULL ? ENOBUFS : 0);
731}
732
733/*
734 * The peer has sent us a CCP ResetRequest, so reset our transmit state.
735 */
736static void
737ng_mppc_reset_req(node_p node)
738{
739 const priv_p priv = node->private;
740 struct ng_mppc_dir *const d = &priv->xmit;
741
742#ifdef NETGRAPH_MPPC_COMPRESSION
743 if (d->history != NULL)
744 MPPC_InitCompressionHistory(d->history);
745#endif
746#ifdef NETGRAPH_MPPC_ENCRYPTION
747 if ((d->cfg.bits & MPPE_STATELESS) == 0)
748 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
749#endif
750 d->flushed = 1;
751}
752
753/*
754 * Generate a new encryption key
755 */
756static void
757ng_mppc_getkey(const u_char *h, u_char *h2, int len)
758{
759 static const u_char pad1[10] =
760 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, };
761 static const u_char pad2[10] =
762 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, };
763 u_char hash[20];
764 SHA1_CTX c;
765 int k;
766
767 bzero(&hash, sizeof(hash));
768 SHA1Init(&c);
769 SHA1Update(&c, h, len);
770 for (k = 0; k < 4; k++)
771 SHA1Update(&c, pad1, sizeof(pad2));
772 SHA1Update(&c, h2, len);
773 for (k = 0; k < 4; k++)
774 SHA1Update(&c, pad2, sizeof(pad2));
775 SHA1Final(hash, &c);
776 bcopy(hash, h2, len);
777}
778
779/*
780 * Update the encryption key
781 */
782static void
783ng_mppc_updatekey(u_int32_t bits,
784 u_char *key0, u_char *key, struct rc4_state *rc4)
785{
786 const int keylen = KEYLEN(bits);
787
788 ng_mppc_getkey(key0, key, keylen);
789 rc4_init(rc4, key, keylen);
790 rc4_crypt(rc4, key, key, keylen);
791 if ((bits & MPPE_128) == 0)
792 bcopy(&ng_mppe_weakenkey, key, sizeof(ng_mppe_weakenkey));
793 rc4_init(rc4, key, keylen);
794}
795
2/*
3 * ng_mppc.c
4 *
5 * Copyright (c) 1996-2000 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 * copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 * Communications, Inc. trademarks, including the mark "WHISTLE
16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 * such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Author: Archie Cobbs <archie@freebsd.org>
38 *
39 * $Whistle: ng_mppc.c,v 1.4 1999/11/25 00:10:12 archie Exp $
40 * $FreeBSD: head/sys/netgraph/ng_mppc.c 68876 2000-11-18 15:17:43Z dwmalone $
41 */
42
43/*
44 * Microsoft PPP compression (MPPC) and encryption (MPPE) netgraph node type.
45 *
46 * You must define one or both of the NETGRAPH_MPPC_COMPRESSION and/or
47 * NETGRAPH_MPPC_ENCRYPTION options for this node type to be useful.
48 */
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/kernel.h>
53#include <sys/mbuf.h>
54#include <sys/malloc.h>
55#include <sys/errno.h>
56#include <sys/syslog.h>
57
58#include <netgraph/ng_message.h>
59#include <netgraph/netgraph.h>
60#include <netgraph/ng_mppc.h>
61
62#include "opt_netgraph.h"
63
64#if !defined(NETGRAPH_MPPC_COMPRESSION) && !defined(NETGRAPH_MPPC_ENCRYPTION)
65#error Need either NETGRAPH_MPPC_COMPRESSION or NETGRAPH_MPPC_ENCRYPTION
66#endif
67
68#ifdef NETGRAPH_MPPC_COMPRESSION
69/* XXX this file doesn't exist yet, but hopefully someday it will... */
70#include <net/mppc.h>
71#endif
72#ifdef NETGRAPH_MPPC_ENCRYPTION
73#include <crypto/rc4/rc4.h>
74#endif
75#include <crypto/sha1.h>
76
77/* Decompression blowup */
78#define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */
79#define MPPC_DECOMP_SAFETY 100 /* plus this much margin */
80
81/* MPPC/MPPE header length */
82#define MPPC_HDRLEN 2
83
84/* Key length */
85#define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8)
86
87/* What sequence number jump is too far */
88#define MPPC_INSANE_JUMP 256
89
90/* MPPC packet header bits */
91#define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */
92#define MPPC_FLAG_RESTART 0x4000 /* compress history restart */
93#define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */
94#define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */
95#define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */
96
97#define MPPE_UPDATE_MASK 0xff /* coherency count when we're */
98#define MPPE_UPDATE_FLAG 0xff /* supposed to update key */
99
100#define MPPC_COMP_OK 0x05
101#define MPPC_DECOMP_OK 0x05
102
103/* Per direction info */
104struct ng_mppc_dir {
105 struct ng_mppc_config cfg; /* configuration */
106 hook_p hook; /* netgraph hook */
107 u_int16_t cc:12; /* coherency count */
108 u_char flushed; /* clean history (xmit only) */
109#ifdef NETGRAPH_MPPC_COMPRESSION
110 u_char *history; /* compression history */
111#endif
112#ifdef NETGRAPH_MPPC_ENCRYPTION
113 u_char key[MPPE_KEY_LEN]; /* session key */
114 struct rc4_state rc4; /* rc4 state */
115#endif
116};
117
118/* Node private data */
119struct ng_mppc_private {
120 struct ng_mppc_dir xmit; /* compress/encrypt config */
121 struct ng_mppc_dir recv; /* decompress/decrypt config */
122 char *ctrlpath; /* path to controlling node */
123};
124typedef struct ng_mppc_private *priv_p;
125
126/* Netgraph node methods */
127static ng_constructor_t ng_mppc_constructor;
128static ng_rcvmsg_t ng_mppc_rcvmsg;
129static ng_shutdown_t ng_mppc_rmnode;
130static ng_newhook_t ng_mppc_newhook;
131static ng_rcvdata_t ng_mppc_rcvdata;
132static ng_disconnect_t ng_mppc_disconnect;
133
134/* Helper functions */
135static int ng_mppc_compress(node_p node,
136 struct mbuf *m, struct mbuf **resultp);
137static int ng_mppc_decompress(node_p node,
138 struct mbuf *m, struct mbuf **resultp);
139static void ng_mppc_getkey(const u_char *h, u_char *h2, int len);
140static void ng_mppc_updatekey(u_int32_t bits,
141 u_char *key0, u_char *key, struct rc4_state *rc4);
142static void ng_mppc_reset_req(node_p node);
143
144/* Node type descriptor */
145static struct ng_type ng_mppc_typestruct = {
146 NG_VERSION,
147 NG_MPPC_NODE_TYPE,
148 NULL,
149 ng_mppc_constructor,
150 ng_mppc_rcvmsg,
151 ng_mppc_rmnode,
152 ng_mppc_newhook,
153 NULL,
154 NULL,
155 ng_mppc_rcvdata,
156 ng_mppc_rcvdata,
157 ng_mppc_disconnect,
158 NULL
159};
160NETGRAPH_INIT(mppc, &ng_mppc_typestruct);
161
162/* Fixed bit pattern to weaken keysize down to 40 bits */
163static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e };
164
165#define ERROUT(x) do { error = (x); goto done; } while (0)
166
167/************************************************************************
168 NETGRAPH NODE STUFF
169 ************************************************************************/
170
171/*
172 * Node type constructor
173 */
174static int
175ng_mppc_constructor(node_p *nodep)
176{
177 priv_p priv;
178 int error;
179
180 /* Allocate private structure */
181 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
182 if (priv == NULL)
183 return (ENOMEM);
184
185 /* Call generic node constructor */
186 if ((error = ng_make_node_common(&ng_mppc_typestruct, nodep))) {
187 FREE(priv, M_NETGRAPH);
188 return (error);
189 }
190 (*nodep)->private = priv;
191
192 /* Done */
193 return (0);
194}
195
196/*
197 * Give our OK for a hook to be added
198 */
199static int
200ng_mppc_newhook(node_p node, hook_p hook, const char *name)
201{
202 const priv_p priv = node->private;
203 hook_p *hookPtr;
204
205 /* Check hook name */
206 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0)
207 hookPtr = &priv->xmit.hook;
208 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0)
209 hookPtr = &priv->recv.hook;
210 else
211 return (EINVAL);
212
213 /* See if already connected */
214 if (*hookPtr != NULL)
215 return (EISCONN);
216
217 /* OK */
218 *hookPtr = hook;
219 return (0);
220}
221
222/*
223 * Receive a control message
224 */
225static int
226ng_mppc_rcvmsg(node_p node, struct ng_mesg *msg,
227 const char *raddr, struct ng_mesg **rptr, hook_p lasthook)
228{
229 const priv_p priv = node->private;
230 struct ng_mesg *resp = NULL;
231 int error = 0;
232
233 switch (msg->header.typecookie) {
234 case NGM_MPPC_COOKIE:
235 switch (msg->header.cmd) {
236 case NGM_MPPC_CONFIG_COMP:
237 case NGM_MPPC_CONFIG_DECOMP:
238 {
239 struct ng_mppc_config *const cfg
240 = (struct ng_mppc_config *)msg->data;
241 const int isComp =
242 msg->header.cmd == NGM_MPPC_CONFIG_COMP;
243 struct ng_mppc_dir *const d = isComp ?
244 &priv->xmit : &priv->recv;
245
246 /* Check configuration */
247 if (msg->header.arglen != sizeof(*cfg))
248 ERROUT(EINVAL);
249 if (cfg->enable) {
250 if ((cfg->bits & ~MPPC_VALID_BITS) != 0)
251 ERROUT(EINVAL);
252#ifndef NETGRAPH_MPPC_COMPRESSION
253 if ((cfg->bits & MPPC_BIT) != 0)
254 ERROUT(EPROTONOSUPPORT);
255#endif
256#ifndef NETGRAPH_MPPC_ENCRYPTION
257 if ((cfg->bits & MPPE_BITS) != 0)
258 ERROUT(EPROTONOSUPPORT);
259#endif
260 } else
261 cfg->bits = 0;
262
263 /* Save return address so we can send reset-req's */
264 if (priv->ctrlpath != NULL) {
265 FREE(priv->ctrlpath, M_NETGRAPH);
266 priv->ctrlpath = NULL;
267 }
268 if (!isComp && raddr != NULL) {
269 MALLOC(priv->ctrlpath, char *,
270 strlen(raddr) + 1, M_NETGRAPH, M_NOWAIT);
271 if (priv->ctrlpath == NULL)
272 ERROUT(ENOMEM);
273 strcpy(priv->ctrlpath, raddr);
274 }
275
276 /* Configuration is OK, reset to it */
277 d->cfg = *cfg;
278
279#ifdef NETGRAPH_MPPC_COMPRESSION
280 /* Initialize state buffers for compression */
281 if (d->history != NULL) {
282 FREE(d->history, M_NETGRAPH);
283 d->history = NULL;
284 }
285 if ((cfg->bits & MPPC_BIT) != 0) {
286 MALLOC(d->history, u_char *,
287 isComp ? MPPC_SizeOfCompressionHistory() :
288 MPPC_SizeOfDecompressionHistory(),
289 M_NETGRAPH, M_NOWAIT);
290 if (d->history == NULL)
291 ERROUT(ENOMEM);
292 if (isComp)
293 MPPC_InitCompressionHistory(d->history);
294 else {
295 MPPC_InitDecompressionHistory(
296 d->history);
297 }
298 }
299#endif
300
301#ifdef NETGRAPH_MPPC_ENCRYPTION
302 /* Generate initial session keys for encryption */
303 if ((cfg->bits & MPPE_BITS) != 0) {
304 const int keylen = KEYLEN(cfg->bits);
305
306 bcopy(cfg->startkey, d->key, keylen);
307 ng_mppc_getkey(cfg->startkey, d->key, keylen);
308 if ((cfg->bits & MPPE_128) == 0) {
309 bcopy(&ng_mppe_weakenkey, d->key,
310 sizeof(ng_mppe_weakenkey));
311 }
312 rc4_init(&d->rc4, d->key, keylen);
313 }
314#endif
315
316 /* Initialize other state */
317 d->cc = 0;
318 d->flushed = 0;
319 break;
320 }
321
322 case NGM_MPPC_RESETREQ:
323 ng_mppc_reset_req(node);
324 break;
325
326 default:
327 error = EINVAL;
328 break;
329 }
330 break;
331 default:
332 error = EINVAL;
333 break;
334 }
335 if (rptr)
336 *rptr = resp;
337 else if (resp)
338 FREE(resp, M_NETGRAPH);
339
340done:
341 FREE(msg, M_NETGRAPH);
342 return (error);
343}
344
345/*
346 * Receive incoming data on our hook.
347 */
348static int
349ng_mppc_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
350 struct mbuf **ret_m, meta_p *ret_meta)
351{
352 const node_p node = hook->node;
353 const priv_p priv = node->private;
354 struct mbuf *out;
355 int error;
356
357 /* Compress and/or encrypt */
358 if (hook == priv->xmit.hook) {
359 if (!priv->xmit.cfg.enable) {
360 NG_FREE_DATA(m, meta);
361 return (ENXIO);
362 }
363 if ((error = ng_mppc_compress(node, m, &out)) != 0) {
364 NG_FREE_DATA(m, meta);
365 return(error);
366 }
367 m_freem(m);
368 NG_SEND_DATA(error, priv->xmit.hook, out, meta);
369 return (error);
370 }
371
372 /* Decompress and/or decrypt */
373 if (hook == priv->recv.hook) {
374 if (!priv->recv.cfg.enable) {
375 NG_FREE_DATA(m, meta);
376 return (ENXIO);
377 }
378 if ((error = ng_mppc_decompress(node, m, &out)) != 0) {
379 NG_FREE_DATA(m, meta);
380 if (error == EINVAL && priv->ctrlpath != NULL) {
381 struct ng_mesg *msg;
382
383 /* Need to send a reset-request */
384 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE,
385 NGM_MPPC_RESETREQ, 0, M_NOWAIT);
386 if (msg == NULL)
387 return (error);
388 ng_send_msg(node, msg, priv->ctrlpath, NULL);
389 }
390 return (error);
391 }
392 m_freem(m);
393 NG_SEND_DATA(error, priv->recv.hook, out, meta);
394 return (error);
395 }
396
397 /* Oops */
398 panic("%s: unknown hook", __FUNCTION__);
399}
400
401/*
402 * Destroy node
403 */
404static int
405ng_mppc_rmnode(node_p node)
406{
407 const priv_p priv = node->private;
408
409 /* Take down netgraph node */
410 node->flags |= NG_INVALID;
411 ng_cutlinks(node);
412 ng_unname(node);
413 if (priv->ctrlpath != NULL)
414 FREE(priv->ctrlpath, M_NETGRAPH);
415#ifdef NETGRAPH_MPPC_COMPRESSION
416 if (priv->xmit.history != NULL)
417 FREE(priv->xmit.history, M_NETGRAPH);
418 if (priv->recv.history != NULL)
419 FREE(priv->recv.history, M_NETGRAPH);
420#endif
421 bzero(priv, sizeof(*priv));
422 FREE(priv, M_NETGRAPH);
423 node->private = NULL;
424 ng_unref(node); /* let the node escape */
425 return (0);
426}
427
428/*
429 * Hook disconnection
430 */
431static int
432ng_mppc_disconnect(hook_p hook)
433{
434 const node_p node = hook->node;
435 const priv_p priv = node->private;
436
437 /* Zero out hook pointer */
438 if (hook == priv->xmit.hook)
439 priv->xmit.hook = NULL;
440 if (hook == priv->recv.hook)
441 priv->recv.hook = NULL;
442
443 /* Go away if no longer connected */
444 if (node->numhooks == 0)
445 ng_rmnode(node);
446 return (0);
447}
448
449/************************************************************************
450 HELPER STUFF
451 ************************************************************************/
452
453/*
454 * Compress/encrypt a packet and put the result in a new mbuf at *resultp.
455 * The original mbuf is not free'd.
456 */
457static int
458ng_mppc_compress(node_p node, struct mbuf *m, struct mbuf **resultp)
459{
460 const priv_p priv = node->private;
461 struct ng_mppc_dir *const d = &priv->xmit;
462 u_char *inbuf, *outbuf;
463 int outlen, inlen;
464 u_int16_t header;
465
466 /* Initialize */
467 *resultp = NULL;
468 header = d->cc;
469 if (d->flushed) {
470 header |= MPPC_FLAG_FLUSHED;
471 d->flushed = 0;
472 }
473
474 /* Work with contiguous regions of memory */
475 inlen = m->m_pkthdr.len;
476 MALLOC(inbuf, u_char *, inlen, M_NETGRAPH, M_NOWAIT);
477 if (inbuf == NULL)
478 return (ENOMEM);
479 m_copydata(m, 0, inlen, (caddr_t)inbuf);
480 if ((d->cfg.bits & MPPC_BIT) != 0)
481 outlen = MPPC_MAX_BLOWUP(inlen);
482 else
483 outlen = MPPC_HDRLEN + inlen;
484 MALLOC(outbuf, u_char *, outlen, M_NETGRAPH, M_NOWAIT);
485 if (outbuf == NULL) {
486 FREE(inbuf, M_NETGRAPH);
487 return (ENOMEM);
488 }
489
490 /* Compress "inbuf" into "outbuf" (if compression enabled) */
491#ifdef NETGRAPH_MPPC_COMPRESSION
492 if ((d->cfg.bits & MPPC_BIT) != 0) {
493 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS;
494 u_char *source, *dest;
495 u_long sourceCnt, destCnt;
496 int rtn;
497
498 /* Prepare to compress */
499 source = inbuf;
500 sourceCnt = inlen;
501 dest = outbuf + MPPC_HDRLEN;
502 destCnt = outlen - MPPC_HDRLEN;
503 if ((d->cfg.bits & MPPE_STATELESS) == 0)
504 flags |= MPPC_SAVE_HISTORY;
505
506 /* Compress */
507 rtn = MPPC_Compress(&source, &dest, &sourceCnt,
508 &destCnt, d->history, flags, 0);
509
510 /* Check return value */
511 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__));
512 if ((rtn & MPPC_EXPANDED) == 0
513 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) {
514 outlen -= destCnt;
515 header |= MPPC_FLAG_COMPRESSED;
516 if ((rtn & MPPC_RESTART_HISTORY) != 0)
517 header |= MPPC_FLAG_RESTART;
518 }
519 d->flushed = (rtn & MPPC_EXPANDED) != 0
520 || (flags & MPPC_SAVE_HISTORY) == 0;
521 }
522#endif
523
524 /* If we did not compress this packet, copy it to output buffer */
525 if ((header & MPPC_FLAG_COMPRESSED) == 0) {
526 bcopy(inbuf, outbuf + MPPC_HDRLEN, inlen);
527 outlen = MPPC_HDRLEN + inlen;
528 }
529 FREE(inbuf, M_NETGRAPH);
530
531 /* Always set the flushed bit in stateless mode */
532 if ((d->cfg.bits & MPPE_STATELESS) != 0)
533 header |= MPPC_FLAG_FLUSHED;
534
535 /* Now encrypt packet (if encryption enabled) */
536#ifdef NETGRAPH_MPPC_ENCRYPTION
537 if ((d->cfg.bits & MPPE_BITS) != 0) {
538
539 /* Set header bits; need to reset key if we say we did */
540 header |= MPPC_FLAG_ENCRYPTED;
541 if ((header & MPPC_FLAG_FLUSHED) != 0)
542 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
543
544 /* Update key if it's time */
545 if ((d->cfg.bits & MPPE_STATELESS) != 0
546 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) {
547 ng_mppc_updatekey(d->cfg.bits,
548 d->cfg.startkey, d->key, &d->rc4);
549 }
550
551 /* Encrypt packet */
552 rc4_crypt(&d->rc4, outbuf + MPPC_HDRLEN,
553 outbuf + MPPC_HDRLEN, outlen - MPPC_HDRLEN);
554 }
555#endif
556
557 /* Update sequence number */
558 d->cc++;
559
560 /* Install header */
561 *((u_int16_t *)outbuf) = htons(header);
562
563 /* Return packet in an mbuf */
564 *resultp = m_devget((caddr_t)outbuf, outlen, 0, NULL, NULL);
565 FREE(outbuf, M_NETGRAPH);
566 return (*resultp == NULL ? ENOBUFS : 0);
567}
568
569/*
570 * Decompress/decrypt packet and put the result in a new mbuf at *resultp.
571 * The original mbuf is not free'd.
572 */
573static int
574ng_mppc_decompress(node_p node, struct mbuf *m, struct mbuf **resultp)
575{
576 const priv_p priv = node->private;
577 struct ng_mppc_dir *const d = &priv->recv;
578 u_int16_t header, cc, numLost;
579 u_char *buf;
580 int len;
581
582 /* Pull off header */
583 if (m->m_pkthdr.len < MPPC_HDRLEN)
584 return (EINVAL);
585 m_copydata(m, 0, MPPC_HDRLEN, (caddr_t)&header);
586 NTOHS(header);
587 cc = (header & MPPC_CCOUNT_MASK);
588
589 /* Copy payload into a contiguous region of memory */
590 len = m->m_pkthdr.len - MPPC_HDRLEN;
591 MALLOC(buf, u_char *, len, M_NETGRAPH, M_NOWAIT);
592 if (buf == NULL)
593 return (ENOMEM);
594 m_copydata(m, MPPC_HDRLEN, len, (caddr_t)buf);
595
596 /* Check for insane jumps in sequence numbering (D.O.S. attack) */
597 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK);
598 if (numLost >= MPPC_INSANE_JUMP) {
599 log(LOG_ERR, "%s: insane jump %d", __FUNCTION__, numLost);
600 priv->recv.cfg.enable = 0;
601 goto failed;
602 }
603
604 /* If flushed bit set, we can always handle packet */
605 if ((header & MPPC_FLAG_FLUSHED) != 0) {
606#ifdef NETGRAPH_MPPC_COMPRESSION
607 if (d->history != NULL)
608 MPPC_InitDecompressionHistory(d->history);
609#endif
610#ifdef NETGRAPH_MPPC_ENCRYPTION
611 if ((d->cfg.bits & MPPE_BITS) != 0) {
612
613 /* Resync as necessary, skipping lost packets */
614 while (d->cc != cc) {
615 if ((d->cfg.bits & MPPE_STATELESS)
616 || (d->cc & MPPE_UPDATE_MASK)
617 == MPPE_UPDATE_FLAG) {
618 ng_mppc_updatekey(d->cfg.bits,
619 d->cfg.startkey, d->key, &d->rc4);
620 }
621 d->cc++;
622 }
623
624 /* Reset key (except in stateless mode, see below) */
625 if ((d->cfg.bits & MPPE_STATELESS) == 0)
626 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
627 }
628#endif
629 d->cc = cc; /* skip over lost seq numbers */
630 numLost = 0; /* act like no packets were lost */
631 }
632
633 /* Can't decode non-sequential packets without a flushed bit */
634 if (numLost != 0)
635 goto failed;
636
637 /* Decrypt packet */
638 if ((header & MPPC_FLAG_ENCRYPTED) != 0) {
639
640 /* Are we not expecting encryption? */
641 if ((d->cfg.bits & MPPE_BITS) == 0) {
642 log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
643 __FUNCTION__, "encrypted");
644 goto failed;
645 }
646
647#ifdef NETGRAPH_MPPC_ENCRYPTION
648 /* Update key if it's time (always in stateless mode) */
649 if ((d->cfg.bits & MPPE_STATELESS) != 0
650 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) {
651 ng_mppc_updatekey(d->cfg.bits,
652 d->cfg.startkey, d->key, &d->rc4);
653 }
654
655 /* Decrypt packet */
656 rc4_crypt(&d->rc4, buf, buf, len);
657#endif
658 } else {
659
660 /* Are we expecting encryption? */
661 if ((d->cfg.bits & MPPE_BITS) != 0) {
662 log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
663 __FUNCTION__, "unencrypted");
664 goto failed;
665 }
666 }
667
668 /* Update coherency count for next time (12 bit arithmetic) */
669 d->cc++;
670
671 /* Check for unexpected compressed packet */
672 if ((header & MPPC_FLAG_COMPRESSED) != 0
673 && (d->cfg.bits & MPPC_BIT) == 0) {
674 log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
675 __FUNCTION__, "compressed");
676failed:
677 FREE(buf, M_NETGRAPH);
678 return (EINVAL);
679 }
680
681#ifdef NETGRAPH_MPPC_COMPRESSION
682 /* Decompress packet */
683 if ((header & MPPC_FLAG_COMPRESSED) != 0) {
684 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS;
685 u_char *decompbuf, *source, *dest;
686 u_long sourceCnt, destCnt;
687 int decomplen, rtn;
688
689 /* Allocate a buffer for decompressed data */
690 MALLOC(decompbuf, u_char *, MPPC_DECOMP_BUFSIZE
691 + MPPC_DECOMP_SAFETY, M_NETGRAPH, M_NOWAIT);
692 if (decompbuf == NULL) {
693 FREE(buf, M_NETGRAPH);
694 return (ENOMEM);
695 }
696 decomplen = MPPC_DECOMP_BUFSIZE;
697
698 /* Prepare to decompress */
699 source = buf;
700 sourceCnt = len;
701 dest = decompbuf;
702 destCnt = decomplen;
703 if ((header & MPPC_FLAG_RESTART) != 0)
704 flags |= MPPC_RESTART_HISTORY;
705
706 /* Decompress */
707 rtn = MPPC_Decompress(&source, &dest,
708 &sourceCnt, &destCnt, d->history, flags);
709
710 /* Check return value */
711 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__));
712 if ((rtn & MPPC_DEST_EXHAUSTED) != 0
713 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) {
714 log(LOG_ERR, "%s: decomp returned 0x%x",
715 __FUNCTION__, rtn);
716 FREE(decompbuf, M_NETGRAPH);
717 goto failed;
718 }
719
720 /* Replace compressed data with decompressed data */
721 FREE(buf, M_NETGRAPH);
722 buf = decompbuf;
723 len = decomplen - destCnt;
724 }
725#endif
726
727 /* Return result in an mbuf */
728 *resultp = m_devget((caddr_t)buf, len, 0, NULL, NULL);
729 FREE(buf, M_NETGRAPH);
730 return (*resultp == NULL ? ENOBUFS : 0);
731}
732
733/*
734 * The peer has sent us a CCP ResetRequest, so reset our transmit state.
735 */
736static void
737ng_mppc_reset_req(node_p node)
738{
739 const priv_p priv = node->private;
740 struct ng_mppc_dir *const d = &priv->xmit;
741
742#ifdef NETGRAPH_MPPC_COMPRESSION
743 if (d->history != NULL)
744 MPPC_InitCompressionHistory(d->history);
745#endif
746#ifdef NETGRAPH_MPPC_ENCRYPTION
747 if ((d->cfg.bits & MPPE_STATELESS) == 0)
748 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
749#endif
750 d->flushed = 1;
751}
752
753/*
754 * Generate a new encryption key
755 */
756static void
757ng_mppc_getkey(const u_char *h, u_char *h2, int len)
758{
759 static const u_char pad1[10] =
760 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, };
761 static const u_char pad2[10] =
762 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, };
763 u_char hash[20];
764 SHA1_CTX c;
765 int k;
766
767 bzero(&hash, sizeof(hash));
768 SHA1Init(&c);
769 SHA1Update(&c, h, len);
770 for (k = 0; k < 4; k++)
771 SHA1Update(&c, pad1, sizeof(pad2));
772 SHA1Update(&c, h2, len);
773 for (k = 0; k < 4; k++)
774 SHA1Update(&c, pad2, sizeof(pad2));
775 SHA1Final(hash, &c);
776 bcopy(hash, h2, len);
777}
778
779/*
780 * Update the encryption key
781 */
782static void
783ng_mppc_updatekey(u_int32_t bits,
784 u_char *key0, u_char *key, struct rc4_state *rc4)
785{
786 const int keylen = KEYLEN(bits);
787
788 ng_mppc_getkey(key0, key, keylen);
789 rc4_init(rc4, key, keylen);
790 rc4_crypt(rc4, key, key, keylen);
791 if ((bits & MPPE_128) == 0)
792 bcopy(&ng_mppe_weakenkey, key, sizeof(ng_mppe_weakenkey));
793 rc4_init(rc4, key, keylen);
794}
795