ng_mppc.c revision 184205
1/* 2 * ng_mppc.c 3 */ 4 5/*- 6 * Copyright (c) 1996-2000 Whistle Communications, Inc. 7 * All rights reserved. 8 * 9 * Subject to the following obligations and disclaimer of warranty, use and 10 * redistribution of this software, in source or object code forms, with or 11 * without modifications are expressly permitted by Whistle Communications; 12 * provided, however, that: 13 * 1. Any and all reproductions of the source or object code must include the 14 * copyright notice above and the following disclaimer of warranties; and 15 * 2. No rights are granted, in any manner or form, to use Whistle 16 * Communications, Inc. trademarks, including the mark "WHISTLE 17 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as 18 * such appears in the above copyright notice or in the software. 19 * 20 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 21 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 22 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 23 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 25 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 26 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 27 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 28 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 29 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 30 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 31 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 32 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 36 * OF SUCH DAMAGE. 37 * 38 * Author: Archie Cobbs <archie@freebsd.org> 39 * 40 * $Whistle: ng_mppc.c,v 1.4 1999/11/25 00:10:12 archie Exp $ 41 * $FreeBSD: head/sys/netgraph/ng_mppc.c 184205 2008-10-23 15:53:51Z des $ 42 */ 43 44/* 45 * Microsoft PPP compression (MPPC) and encryption (MPPE) netgraph node type. 46 * 47 * You must define one or both of the NETGRAPH_MPPC_COMPRESSION and/or 48 * NETGRAPH_MPPC_ENCRYPTION options for this node type to be useful. 49 */ 50 51#include <sys/param.h> 52#include <sys/systm.h> 53#include <sys/kernel.h> 54#include <sys/mbuf.h> 55#include <sys/malloc.h> 56#include <sys/errno.h> 57#include <sys/syslog.h> 58 59#include <netgraph/ng_message.h> 60#include <netgraph/netgraph.h> 61#include <netgraph/ng_mppc.h> 62 63#include "opt_netgraph.h" 64 65#if !defined(NETGRAPH_MPPC_COMPRESSION) && !defined(NETGRAPH_MPPC_ENCRYPTION) 66#ifdef KLD_MODULE 67/* XXX NETGRAPH_MPPC_COMPRESSION isn't functional yet */ 68#define NETGRAPH_MPPC_ENCRYPTION 69#else 70/* This case is indicative of an error in sys/conf files */ 71#error Need either NETGRAPH_MPPC_COMPRESSION or NETGRAPH_MPPC_ENCRYPTION 72#endif 73#endif 74 75#ifdef NG_SEPARATE_MALLOC 76MALLOC_DEFINE(M_NETGRAPH_MPPC, "netgraph_mppc", "netgraph mppc node "); 77#else 78#define M_NETGRAPH_MPPC M_NETGRAPH 79#endif 80 81#ifdef NETGRAPH_MPPC_COMPRESSION 82/* XXX this file doesn't exist yet, but hopefully someday it will... */ 83#include <net/mppc.h> 84#endif 85#ifdef NETGRAPH_MPPC_ENCRYPTION 86#include <crypto/rc4/rc4.h> 87#endif 88#include <crypto/sha1.h> 89 90/* Decompression blowup */ 91#define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */ 92#define MPPC_DECOMP_SAFETY 100 /* plus this much margin */ 93 94/* MPPC/MPPE header length */ 95#define MPPC_HDRLEN 2 96 97/* Key length */ 98#define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8) 99 100/* 101 * When packets are lost with MPPE, we may have to re-key arbitrarily 102 * many times to 'catch up' to the new jumped-ahead sequence number. 103 * Since this can be expensive, we pose a limit on how many re-keyings 104 * we will do at one time to avoid a possible D.O.S. vulnerability. 105 * This should instead be a configurable parameter. 106 */ 107#define MPPE_MAX_REKEY 1000 108 109/* MPPC packet header bits */ 110#define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */ 111#define MPPC_FLAG_RESTART 0x4000 /* compress history restart */ 112#define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */ 113#define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */ 114#define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */ 115 116#define MPPC_CCOUNT_INC(d) ((d) = (((d) + 1) & MPPC_CCOUNT_MASK)) 117 118#define MPPE_UPDATE_MASK 0xff /* coherency count when we're */ 119#define MPPE_UPDATE_FLAG 0xff /* supposed to update key */ 120 121#define MPPC_COMP_OK 0x05 122#define MPPC_DECOMP_OK 0x05 123 124/* Per direction info */ 125struct ng_mppc_dir { 126 struct ng_mppc_config cfg; /* configuration */ 127 hook_p hook; /* netgraph hook */ 128 u_int16_t cc:12; /* coherency count */ 129 u_char flushed; /* clean history (xmit only) */ 130#ifdef NETGRAPH_MPPC_COMPRESSION 131 u_char *history; /* compression history */ 132#endif 133#ifdef NETGRAPH_MPPC_ENCRYPTION 134 u_char key[MPPE_KEY_LEN]; /* session key */ 135 struct rc4_state rc4; /* rc4 state */ 136#endif 137}; 138 139/* Node private data */ 140struct ng_mppc_private { 141 struct ng_mppc_dir xmit; /* compress/encrypt config */ 142 struct ng_mppc_dir recv; /* decompress/decrypt config */ 143 ng_ID_t ctrlnode; /* path to controlling node */ 144}; 145typedef struct ng_mppc_private *priv_p; 146 147/* Netgraph node methods */ 148static ng_constructor_t ng_mppc_constructor; 149static ng_rcvmsg_t ng_mppc_rcvmsg; 150static ng_shutdown_t ng_mppc_shutdown; 151static ng_newhook_t ng_mppc_newhook; 152static ng_rcvdata_t ng_mppc_rcvdata; 153static ng_disconnect_t ng_mppc_disconnect; 154 155/* Helper functions */ 156static int ng_mppc_compress(node_p node, 157 struct mbuf **datap); 158static int ng_mppc_decompress(node_p node, 159 struct mbuf **datap); 160#ifdef NETGRAPH_MPPC_ENCRYPTION 161static void ng_mppc_getkey(const u_char *h, u_char *h2, int len); 162static void ng_mppc_updatekey(u_int32_t bits, 163 u_char *key0, u_char *key, struct rc4_state *rc4); 164#endif 165static void ng_mppc_reset_req(node_p node); 166 167/* Node type descriptor */ 168static struct ng_type ng_mppc_typestruct = { 169 .version = NG_ABI_VERSION, 170 .name = NG_MPPC_NODE_TYPE, 171 .constructor = ng_mppc_constructor, 172 .rcvmsg = ng_mppc_rcvmsg, 173 .shutdown = ng_mppc_shutdown, 174 .newhook = ng_mppc_newhook, 175 .rcvdata = ng_mppc_rcvdata, 176 .disconnect = ng_mppc_disconnect, 177}; 178NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 179 180#ifdef NETGRAPH_MPPC_ENCRYPTION 181/* Depend on separate rc4 module */ 182MODULE_DEPEND(ng_mppc, rc4, 1, 1, 1); 183#endif 184 185/* Fixed bit pattern to weaken keysize down to 40 or 56 bits */ 186static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e }; 187 188#define ERROUT(x) do { error = (x); goto done; } while (0) 189 190/************************************************************************ 191 NETGRAPH NODE STUFF 192 ************************************************************************/ 193 194/* 195 * Node type constructor 196 */ 197static int 198ng_mppc_constructor(node_p node) 199{ 200 priv_p priv; 201 202 /* Allocate private structure */ 203 priv = malloc(sizeof(*priv), M_NETGRAPH_MPPC, M_NOWAIT | M_ZERO); 204 if (priv == NULL) 205 return (ENOMEM); 206 207 NG_NODE_SET_PRIVATE(node, priv); 208 209 /* This node is not thread safe. */ 210 NG_NODE_FORCE_WRITER(node); 211 212 /* Done */ 213 return (0); 214} 215 216/* 217 * Give our OK for a hook to be added 218 */ 219static int 220ng_mppc_newhook(node_p node, hook_p hook, const char *name) 221{ 222 const priv_p priv = NG_NODE_PRIVATE(node); 223 hook_p *hookPtr; 224 225 /* Check hook name */ 226 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0) 227 hookPtr = &priv->xmit.hook; 228 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0) 229 hookPtr = &priv->recv.hook; 230 else 231 return (EINVAL); 232 233 /* See if already connected */ 234 if (*hookPtr != NULL) 235 return (EISCONN); 236 237 /* OK */ 238 *hookPtr = hook; 239 return (0); 240} 241 242/* 243 * Receive a control message 244 */ 245static int 246ng_mppc_rcvmsg(node_p node, item_p item, hook_p lasthook) 247{ 248 const priv_p priv = NG_NODE_PRIVATE(node); 249 struct ng_mesg *resp = NULL; 250 int error = 0; 251 struct ng_mesg *msg; 252 253 NGI_GET_MSG(item, msg); 254 switch (msg->header.typecookie) { 255 case NGM_MPPC_COOKIE: 256 switch (msg->header.cmd) { 257 case NGM_MPPC_CONFIG_COMP: 258 case NGM_MPPC_CONFIG_DECOMP: 259 { 260 struct ng_mppc_config *const cfg 261 = (struct ng_mppc_config *)msg->data; 262 const int isComp = 263 msg->header.cmd == NGM_MPPC_CONFIG_COMP; 264 struct ng_mppc_dir *const d = isComp ? 265 &priv->xmit : &priv->recv; 266 267 /* Check configuration */ 268 if (msg->header.arglen != sizeof(*cfg)) 269 ERROUT(EINVAL); 270 if (cfg->enable) { 271 if ((cfg->bits & ~MPPC_VALID_BITS) != 0) 272 ERROUT(EINVAL); 273#ifndef NETGRAPH_MPPC_COMPRESSION 274 if ((cfg->bits & MPPC_BIT) != 0) 275 ERROUT(EPROTONOSUPPORT); 276#endif 277#ifndef NETGRAPH_MPPC_ENCRYPTION 278 if ((cfg->bits & MPPE_BITS) != 0) 279 ERROUT(EPROTONOSUPPORT); 280#endif 281 } else 282 cfg->bits = 0; 283 284 /* Save return address so we can send reset-req's */ 285 if (!isComp) 286 priv->ctrlnode = NGI_RETADDR(item); 287 288 /* Configuration is OK, reset to it */ 289 d->cfg = *cfg; 290 291#ifdef NETGRAPH_MPPC_COMPRESSION 292 /* Initialize state buffers for compression */ 293 if (d->history != NULL) { 294 free(d->history, M_NETGRAPH_MPPC); 295 d->history = NULL; 296 } 297 if ((cfg->bits & MPPC_BIT) != 0) { 298 d->history = malloc( isComp ? MPPC_SizeOfCompressionHistory() : 299 MPPC_SizeOfDecompressionHistory(), 300 M_NETGRAPH_MPPC, M_NOWAIT); 301 if (d->history == NULL) 302 ERROUT(ENOMEM); 303 if (isComp) 304 MPPC_InitCompressionHistory(d->history); 305 else { 306 MPPC_InitDecompressionHistory( 307 d->history); 308 } 309 } 310#endif 311 312#ifdef NETGRAPH_MPPC_ENCRYPTION 313 /* Generate initial session keys for encryption */ 314 if ((cfg->bits & MPPE_BITS) != 0) { 315 const int keylen = KEYLEN(cfg->bits); 316 317 bcopy(cfg->startkey, d->key, keylen); 318 ng_mppc_getkey(cfg->startkey, d->key, keylen); 319 if ((cfg->bits & MPPE_40) != 0) 320 bcopy(&ng_mppe_weakenkey, d->key, 3); 321 else if ((cfg->bits & MPPE_56) != 0) 322 bcopy(&ng_mppe_weakenkey, d->key, 1); 323 rc4_init(&d->rc4, d->key, keylen); 324 } 325#endif 326 327 /* Initialize other state */ 328 d->cc = 0; 329 d->flushed = 0; 330 break; 331 } 332 333 case NGM_MPPC_RESETREQ: 334 ng_mppc_reset_req(node); 335 break; 336 337 default: 338 error = EINVAL; 339 break; 340 } 341 break; 342 default: 343 error = EINVAL; 344 break; 345 } 346done: 347 NG_RESPOND_MSG(error, node, item, resp); 348 NG_FREE_MSG(msg); 349 return (error); 350} 351 352/* 353 * Receive incoming data on our hook. 354 */ 355static int 356ng_mppc_rcvdata(hook_p hook, item_p item) 357{ 358 const node_p node = NG_HOOK_NODE(hook); 359 const priv_p priv = NG_NODE_PRIVATE(node); 360 int error; 361 struct mbuf *m; 362 363 NGI_GET_M(item, m); 364 /* Compress and/or encrypt */ 365 if (hook == priv->xmit.hook) { 366 if (!priv->xmit.cfg.enable) { 367 NG_FREE_M(m); 368 NG_FREE_ITEM(item); 369 return (ENXIO); 370 } 371 if ((error = ng_mppc_compress(node, &m)) != 0) { 372 NG_FREE_ITEM(item); 373 return(error); 374 } 375 NG_FWD_NEW_DATA(error, item, priv->xmit.hook, m); 376 return (error); 377 } 378 379 /* Decompress and/or decrypt */ 380 if (hook == priv->recv.hook) { 381 if (!priv->recv.cfg.enable) { 382 NG_FREE_M(m); 383 NG_FREE_ITEM(item); 384 return (ENXIO); 385 } 386 if ((error = ng_mppc_decompress(node, &m)) != 0) { 387 NG_FREE_ITEM(item); 388 if (error == EINVAL && priv->ctrlnode != 0) { 389 struct ng_mesg *msg; 390 391 /* Need to send a reset-request */ 392 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE, 393 NGM_MPPC_RESETREQ, 0, M_NOWAIT); 394 if (msg == NULL) 395 return (error); 396 NG_SEND_MSG_ID(error, node, msg, 397 priv->ctrlnode, 0); 398 } 399 return (error); 400 } 401 NG_FWD_NEW_DATA(error, item, priv->recv.hook, m); 402 return (error); 403 } 404 405 /* Oops */ 406 panic("%s: unknown hook", __func__); 407#ifdef RESTARTABLE_PANICS 408 return (EINVAL); 409#endif 410} 411 412/* 413 * Destroy node 414 */ 415static int 416ng_mppc_shutdown(node_p node) 417{ 418 const priv_p priv = NG_NODE_PRIVATE(node); 419 420 /* Take down netgraph node */ 421#ifdef NETGRAPH_MPPC_COMPRESSION 422 if (priv->xmit.history != NULL) 423 free(priv->xmit.history, M_NETGRAPH_MPPC); 424 if (priv->recv.history != NULL) 425 free(priv->recv.history, M_NETGRAPH_MPPC); 426#endif 427 bzero(priv, sizeof(*priv)); 428 free(priv, M_NETGRAPH_MPPC); 429 NG_NODE_SET_PRIVATE(node, NULL); 430 NG_NODE_UNREF(node); /* let the node escape */ 431 return (0); 432} 433 434/* 435 * Hook disconnection 436 */ 437static int 438ng_mppc_disconnect(hook_p hook) 439{ 440 const node_p node = NG_HOOK_NODE(hook); 441 const priv_p priv = NG_NODE_PRIVATE(node); 442 443 /* Zero out hook pointer */ 444 if (hook == priv->xmit.hook) 445 priv->xmit.hook = NULL; 446 if (hook == priv->recv.hook) 447 priv->recv.hook = NULL; 448 449 /* Go away if no longer connected */ 450 if ((NG_NODE_NUMHOOKS(node) == 0) 451 && NG_NODE_IS_VALID(node)) 452 ng_rmnode_self(node); 453 return (0); 454} 455 456/************************************************************************ 457 HELPER STUFF 458 ************************************************************************/ 459 460/* 461 * Compress/encrypt a packet and put the result in a new mbuf at *resultp. 462 * The original mbuf is not free'd. 463 */ 464static int 465ng_mppc_compress(node_p node, struct mbuf **datap) 466{ 467 const priv_p priv = NG_NODE_PRIVATE(node); 468 struct ng_mppc_dir *const d = &priv->xmit; 469 u_int16_t header; 470 struct mbuf *m = *datap; 471 472 /* Initialize */ 473 header = d->cc; 474 475 /* Always set the flushed bit in stateless mode */ 476 if (d->flushed || ((d->cfg.bits & MPPE_STATELESS) != 0)) { 477 header |= MPPC_FLAG_FLUSHED; 478 d->flushed = 0; 479 } 480 481 /* Compress packet (if compression enabled) */ 482#ifdef NETGRAPH_MPPC_COMPRESSION 483 if ((d->cfg.bits & MPPC_BIT) != 0) { 484 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS; 485 u_char *inbuf, *outbuf; 486 int outlen, inlen; 487 u_char *source, *dest; 488 u_long sourceCnt, destCnt; 489 int rtn; 490 491 /* Work with contiguous regions of memory. */ 492 inlen = m->m_pkthdr.len; 493 inbuf = malloc(inlen, M_NETGRAPH_MPPC, M_NOWAIT); 494 if (inbuf == NULL) { 495 m_freem(m); 496 return (ENOMEM); 497 } 498 m_copydata(m, 0, inlen, (caddr_t)inbuf); 499 500 outlen = MPPC_MAX_BLOWUP(inlen); 501 outbuf = malloc(outlen, M_NETGRAPH_MPPC, M_NOWAIT); 502 if (outbuf == NULL) { 503 m_freem(m); 504 free(inbuf, M_NETGRAPH_MPPC); 505 return (ENOMEM); 506 } 507 508 /* Prepare to compress */ 509 source = inbuf; 510 sourceCnt = inlen; 511 dest = outbuf; 512 destCnt = outlen; 513 if ((d->cfg.bits & MPPE_STATELESS) == 0) 514 flags |= MPPC_SAVE_HISTORY; 515 516 /* Compress */ 517 rtn = MPPC_Compress(&source, &dest, &sourceCnt, 518 &destCnt, d->history, flags, 0); 519 520 /* Check return value */ 521 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 522 if ((rtn & MPPC_EXPANDED) == 0 523 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) { 524 outlen -= destCnt; 525 header |= MPPC_FLAG_COMPRESSED; 526 if ((rtn & MPPC_RESTART_HISTORY) != 0) 527 header |= MPPC_FLAG_RESTART; 528 529 /* Replace m by the compresed one. */ 530 m_freem(m); 531 m = m_devget((caddr_t)outbuf, outlen, 0, NULL, NULL); 532 } 533 d->flushed = (rtn & MPPC_EXPANDED) != 0 534 || (flags & MPPC_SAVE_HISTORY) == 0; 535 536 free(inbuf, M_NETGRAPH_MPPC); 537 free(outbuf, M_NETGRAPH_MPPC); 538 539 /* Check m_devget() result. */ 540 if (m == NULL) 541 return (ENOMEM); 542 } 543#endif 544 545 /* Now encrypt packet (if encryption enabled) */ 546#ifdef NETGRAPH_MPPC_ENCRYPTION 547 if ((d->cfg.bits & MPPE_BITS) != 0) { 548 struct mbuf *m1; 549 550 /* Set header bits */ 551 header |= MPPC_FLAG_ENCRYPTED; 552 553 /* Update key if it's time */ 554 if ((d->cfg.bits & MPPE_STATELESS) != 0 555 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 556 ng_mppc_updatekey(d->cfg.bits, 557 d->cfg.startkey, d->key, &d->rc4); 558 } else if ((header & MPPC_FLAG_FLUSHED) != 0) { 559 /* Need to reset key if we say we did 560 and ng_mppc_updatekey wasn't called to do it also. */ 561 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 562 } 563 564 /* We must own the mbuf chain exclusively to modify it. */ 565 m = m_unshare(m, M_DONTWAIT); 566 if (m == NULL) 567 return (ENOMEM); 568 569 /* Encrypt packet */ 570 m1 = m; 571 while (m1) { 572 rc4_crypt(&d->rc4, mtod(m1, u_char *), 573 mtod(m1, u_char *), m1->m_len); 574 m1 = m1->m_next; 575 } 576 } 577#endif 578 579 /* Update coherency count for next time (12 bit arithmetic) */ 580 MPPC_CCOUNT_INC(d->cc); 581 582 /* Install header */ 583 M_PREPEND(m, MPPC_HDRLEN, M_DONTWAIT); 584 if (m != NULL) 585 *(mtod(m, uint16_t *)) = htons(header); 586 587 *datap = m; 588 return (*datap == NULL ? ENOBUFS : 0); 589} 590 591/* 592 * Decompress/decrypt packet and put the result in a new mbuf at *resultp. 593 * The original mbuf is not free'd. 594 */ 595static int 596ng_mppc_decompress(node_p node, struct mbuf **datap) 597{ 598 const priv_p priv = NG_NODE_PRIVATE(node); 599 struct ng_mppc_dir *const d = &priv->recv; 600 u_int16_t header, cc; 601 u_int numLost; 602 struct mbuf *m = *datap; 603 604 /* Pull off header */ 605 if (m->m_pkthdr.len < MPPC_HDRLEN) { 606 m_freem(m); 607 return (EINVAL); 608 } 609 m_copydata(m, 0, MPPC_HDRLEN, (caddr_t)&header); 610 header = ntohs(header); 611 cc = (header & MPPC_CCOUNT_MASK); 612 m_adj(m, MPPC_HDRLEN); 613 614 /* Check for an unexpected jump in the sequence number */ 615 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 616 617 /* If flushed bit set, we can always handle packet */ 618 if ((header & MPPC_FLAG_FLUSHED) != 0) { 619#ifdef NETGRAPH_MPPC_COMPRESSION 620 if (d->history != NULL) 621 MPPC_InitDecompressionHistory(d->history); 622#endif 623#ifdef NETGRAPH_MPPC_ENCRYPTION 624 if ((d->cfg.bits & MPPE_BITS) != 0) { 625 u_int rekey; 626 627 /* How many times are we going to have to re-key? */ 628 rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ? 629 numLost : (numLost / (MPPE_UPDATE_MASK + 1)); 630 if (rekey > MPPE_MAX_REKEY) { 631 log(LOG_ERR, "%s: too many (%d) packets" 632 " dropped, disabling node %p!", 633 __func__, numLost, node); 634 priv->recv.cfg.enable = 0; 635 goto failed; 636 } 637 638 /* Re-key as necessary to catch up to peer */ 639 while (d->cc != cc) { 640 if ((d->cfg.bits & MPPE_STATELESS) != 0 641 || (d->cc & MPPE_UPDATE_MASK) 642 == MPPE_UPDATE_FLAG) { 643 ng_mppc_updatekey(d->cfg.bits, 644 d->cfg.startkey, d->key, &d->rc4); 645 } 646 MPPC_CCOUNT_INC(d->cc); 647 } 648 649 /* Reset key (except in stateless mode, see below) */ 650 if ((d->cfg.bits & MPPE_STATELESS) == 0) 651 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 652 } 653#endif 654 d->cc = cc; /* skip over lost seq numbers */ 655 numLost = 0; /* act like no packets were lost */ 656 } 657 658 /* Can't decode non-sequential packets without a flushed bit */ 659 if (numLost != 0) 660 goto failed; 661 662 /* Decrypt packet */ 663 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 664#ifdef NETGRAPH_MPPC_ENCRYPTION 665 struct mbuf *m1; 666#endif 667 668 /* Are we not expecting encryption? */ 669 if ((d->cfg.bits & MPPE_BITS) == 0) { 670 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 671 __func__, "encrypted"); 672 goto failed; 673 } 674 675#ifdef NETGRAPH_MPPC_ENCRYPTION 676 /* Update key if it's time (always in stateless mode) */ 677 if ((d->cfg.bits & MPPE_STATELESS) != 0 678 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 679 ng_mppc_updatekey(d->cfg.bits, 680 d->cfg.startkey, d->key, &d->rc4); 681 } 682 683 /* We must own the mbuf chain exclusively to modify it. */ 684 m = m_unshare(m, M_DONTWAIT); 685 if (m == NULL) 686 return (ENOMEM); 687 688 /* Decrypt packet */ 689 m1 = m; 690 while (m1 != NULL) { 691 rc4_crypt(&d->rc4, mtod(m1, u_char *), 692 mtod(m1, u_char *), m1->m_len); 693 m1 = m1->m_next; 694 } 695#endif 696 } else { 697 698 /* Are we expecting encryption? */ 699 if ((d->cfg.bits & MPPE_BITS) != 0) { 700 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 701 __func__, "unencrypted"); 702 goto failed; 703 } 704 } 705 706 /* Update coherency count for next time (12 bit arithmetic) */ 707 MPPC_CCOUNT_INC(d->cc); 708 709 /* Check for unexpected compressed packet */ 710 if ((header & MPPC_FLAG_COMPRESSED) != 0 711 && (d->cfg.bits & MPPC_BIT) == 0) { 712 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 713 __func__, "compressed"); 714failed: 715 m_freem(m); 716 return (EINVAL); 717 } 718 719#ifdef NETGRAPH_MPPC_COMPRESSION 720 /* Decompress packet */ 721 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 722 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 723 u_char *decompbuf, *source, *dest; 724 u_long sourceCnt, destCnt; 725 int decomplen, rtn; 726 u_char *buf; 727 int len; 728 729 /* Copy payload into a contiguous region of memory. */ 730 len = m->m_pkthdr.len; 731 buf = malloc(len, M_NETGRAPH_MPPC, M_NOWAIT); 732 if (buf == NULL) { 733 m_freem(m); 734 return (ENOMEM); 735 } 736 m_copydata(m, 0, len, (caddr_t)buf); 737 738 /* Allocate a buffer for decompressed data */ 739 decompbuf = malloc(MPPC_DECOMP_BUFSIZE + MPPC_DECOMP_SAFETY, 740 M_NETGRAPH_MPPC, M_NOWAIT); 741 if (decompbuf == NULL) { 742 m_freem(m); 743 free(buf, M_NETGRAPH_MPPC); 744 return (ENOMEM); 745 } 746 decomplen = MPPC_DECOMP_BUFSIZE; 747 748 /* Prepare to decompress */ 749 source = buf; 750 sourceCnt = len; 751 dest = decompbuf; 752 destCnt = decomplen; 753 if ((header & MPPC_FLAG_RESTART) != 0) 754 flags |= MPPC_RESTART_HISTORY; 755 756 /* Decompress */ 757 rtn = MPPC_Decompress(&source, &dest, 758 &sourceCnt, &destCnt, d->history, flags); 759 760 /* Check return value */ 761 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 762 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 763 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 764 log(LOG_ERR, "%s: decomp returned 0x%x", 765 __func__, rtn); 766 free(buf, M_NETGRAPH_MPPC); 767 free(decompbuf, M_NETGRAPH_MPPC); 768 goto failed; 769 } 770 771 /* Replace compressed data with decompressed data */ 772 free(buf, M_NETGRAPH_MPPC); 773 len = decomplen - destCnt; 774 775 m_freem(m); 776 m = m_devget((caddr_t)decompbuf, len, 0, NULL, NULL); 777 free(decompbuf, M_NETGRAPH_MPPC); 778 } 779#endif 780 781 /* Return result in an mbuf */ 782 *datap = m; 783 return (*datap == NULL ? ENOBUFS : 0); 784} 785 786/* 787 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 788 */ 789static void 790ng_mppc_reset_req(node_p node) 791{ 792 const priv_p priv = NG_NODE_PRIVATE(node); 793 struct ng_mppc_dir *const d = &priv->xmit; 794 795#ifdef NETGRAPH_MPPC_COMPRESSION 796 if (d->history != NULL) 797 MPPC_InitCompressionHistory(d->history); 798#endif 799#ifdef NETGRAPH_MPPC_ENCRYPTION 800 if ((d->cfg.bits & MPPE_STATELESS) == 0) 801 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 802#endif 803 d->flushed = 1; 804} 805 806#ifdef NETGRAPH_MPPC_ENCRYPTION 807/* 808 * Generate a new encryption key 809 */ 810static void 811ng_mppc_getkey(const u_char *h, u_char *h2, int len) 812{ 813 static const u_char pad1[10] = 814 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 815 static const u_char pad2[10] = 816 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 817 u_char hash[20]; 818 SHA1_CTX c; 819 int k; 820 821 SHA1Init(&c); 822 SHA1Update(&c, h, len); 823 for (k = 0; k < 4; k++) 824 SHA1Update(&c, pad1, sizeof(pad1)); 825 SHA1Update(&c, h2, len); 826 for (k = 0; k < 4; k++) 827 SHA1Update(&c, pad2, sizeof(pad2)); 828 SHA1Final(hash, &c); 829 bcopy(hash, h2, len); 830} 831 832/* 833 * Update the encryption key 834 */ 835static void 836ng_mppc_updatekey(u_int32_t bits, 837 u_char *key0, u_char *key, struct rc4_state *rc4) 838{ 839 const int keylen = KEYLEN(bits); 840 841 ng_mppc_getkey(key0, key, keylen); 842 rc4_init(rc4, key, keylen); 843 rc4_crypt(rc4, key, key, keylen); 844 if ((bits & MPPE_40) != 0) 845 bcopy(&ng_mppe_weakenkey, key, 3); 846 else if ((bits & MPPE_56) != 0) 847 bcopy(&ng_mppe_weakenkey, key, 1); 848 rc4_init(rc4, key, keylen); 849} 850#endif 851 852