ng_mppc.c revision 70700
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 70700 2001-01-06 00:46:47Z julian $ 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 ng_ID_t ctrlnode; /* 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_shutdown; 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_ABI_VERSION, 147 NG_MPPC_NODE_TYPE, 148 NULL, 149 ng_mppc_constructor, 150 ng_mppc_rcvmsg, 151 ng_mppc_shutdown, 152 ng_mppc_newhook, 153 NULL, 154 NULL, 155 ng_mppc_rcvdata, 156 ng_mppc_disconnect, 157 NULL 158}; 159NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 160 161/* Fixed bit pattern to weaken keysize down to 40 bits */ 162static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e }; 163 164#define ERROUT(x) do { error = (x); goto done; } while (0) 165 166/************************************************************************ 167 NETGRAPH NODE STUFF 168 ************************************************************************/ 169 170/* 171 * Node type constructor 172 */ 173static int 174ng_mppc_constructor(node_p node) 175{ 176 priv_p priv; 177 178 /* Allocate private structure */ 179 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO); 180 if (priv == NULL) 181 return (ENOMEM); 182 183 node->private = priv; 184 185 /* Done */ 186 return (0); 187} 188 189/* 190 * Give our OK for a hook to be added 191 */ 192static int 193ng_mppc_newhook(node_p node, hook_p hook, const char *name) 194{ 195 const priv_p priv = node->private; 196 hook_p *hookPtr; 197 198 /* Check hook name */ 199 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0) 200 hookPtr = &priv->xmit.hook; 201 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0) 202 hookPtr = &priv->recv.hook; 203 else 204 return (EINVAL); 205 206 /* See if already connected */ 207 if (*hookPtr != NULL) 208 return (EISCONN); 209 210 /* OK */ 211 *hookPtr = hook; 212 return (0); 213} 214 215/* 216 * Receive a control message 217 */ 218static int 219ng_mppc_rcvmsg(node_p node, item_p item, hook_p lasthook) 220{ 221 const priv_p priv = node->private; 222 struct ng_mesg *resp = NULL; 223 int error = 0; 224 struct ng_mesg *msg; 225 226 NGI_GET_MSG(item, msg); 227 switch (msg->header.typecookie) { 228 case NGM_MPPC_COOKIE: 229 switch (msg->header.cmd) { 230 case NGM_MPPC_CONFIG_COMP: 231 case NGM_MPPC_CONFIG_DECOMP: 232 { 233 struct ng_mppc_config *const cfg 234 = (struct ng_mppc_config *)msg->data; 235 const int isComp = 236 msg->header.cmd == NGM_MPPC_CONFIG_COMP; 237 struct ng_mppc_dir *const d = isComp ? 238 &priv->xmit : &priv->recv; 239 240 /* Check configuration */ 241 if (msg->header.arglen != sizeof(*cfg)) 242 ERROUT(EINVAL); 243 if (cfg->enable) { 244 if ((cfg->bits & ~MPPC_VALID_BITS) != 0) 245 ERROUT(EINVAL); 246#ifndef NETGRAPH_MPPC_COMPRESSION 247 if ((cfg->bits & MPPC_BIT) != 0) 248 ERROUT(EPROTONOSUPPORT); 249#endif 250#ifndef NETGRAPH_MPPC_ENCRYPTION 251 if ((cfg->bits & MPPE_BITS) != 0) 252 ERROUT(EPROTONOSUPPORT); 253#endif 254 } else 255 cfg->bits = 0; 256 257 /* Save return address so we can send reset-req's */ 258 priv->ctrlnode = NGI_RETADDR(item); 259 260 /* Configuration is OK, reset to it */ 261 d->cfg = *cfg; 262 263#ifdef NETGRAPH_MPPC_COMPRESSION 264 /* Initialize state buffers for compression */ 265 if (d->history != NULL) { 266 FREE(d->history, M_NETGRAPH); 267 d->history = NULL; 268 } 269 if ((cfg->bits & MPPC_BIT) != 0) { 270 MALLOC(d->history, u_char *, 271 isComp ? MPPC_SizeOfCompressionHistory() : 272 MPPC_SizeOfDecompressionHistory(), 273 M_NETGRAPH, M_NOWAIT); 274 if (d->history == NULL) 275 ERROUT(ENOMEM); 276 if (isComp) 277 MPPC_InitCompressionHistory(d->history); 278 else { 279 MPPC_InitDecompressionHistory( 280 d->history); 281 } 282 } 283#endif 284 285#ifdef NETGRAPH_MPPC_ENCRYPTION 286 /* Generate initial session keys for encryption */ 287 if ((cfg->bits & MPPE_BITS) != 0) { 288 const int keylen = KEYLEN(cfg->bits); 289 290 bcopy(cfg->startkey, d->key, keylen); 291 ng_mppc_getkey(cfg->startkey, d->key, keylen); 292 if ((cfg->bits & MPPE_128) == 0) { 293 bcopy(&ng_mppe_weakenkey, d->key, 294 sizeof(ng_mppe_weakenkey)); 295 } 296 rc4_init(&d->rc4, d->key, keylen); 297 } 298#endif 299 300 /* Initialize other state */ 301 d->cc = 0; 302 d->flushed = 0; 303 break; 304 } 305 306 case NGM_MPPC_RESETREQ: 307 ng_mppc_reset_req(node); 308 break; 309 310 default: 311 error = EINVAL; 312 break; 313 } 314 break; 315 default: 316 error = EINVAL; 317 break; 318 } 319done: 320 NG_RESPOND_MSG(error, node, item, resp); 321 NG_FREE_MSG(msg); 322 return (error); 323} 324 325/* 326 * Receive incoming data on our hook. 327 */ 328static int 329ng_mppc_rcvdata(hook_p hook, item_p item) 330{ 331 const node_p node = hook->node; 332 const priv_p priv = node->private; 333 struct mbuf *out; 334 int error; 335 struct mbuf *m; 336 337 NGI_GET_M(item, m); 338 /* Compress and/or encrypt */ 339 if (hook == priv->xmit.hook) { 340 if (!priv->xmit.cfg.enable) { 341 NG_FREE_M(m); 342 NG_FREE_ITEM(item); 343 return (ENXIO); 344 } 345 if ((error = ng_mppc_compress(node, m, &out)) != 0) { 346 NG_FREE_M(m); 347 NG_FREE_ITEM(item); 348 return(error); 349 } 350 NG_FREE_M(m); 351 NG_FWD_NEW_DATA(error, item, priv->xmit.hook, out); 352 return (error); 353 } 354 355 /* Decompress and/or decrypt */ 356 if (hook == priv->recv.hook) { 357 if (!priv->recv.cfg.enable) { 358 NG_FREE_M(m); 359 NG_FREE_ITEM(item); 360 return (ENXIO); 361 } 362 if ((error = ng_mppc_decompress(node, m, &out)) != 0) { 363 NG_FREE_M(m); 364 NG_FREE_ITEM(item); 365 if (error == EINVAL && priv->ctrlnode != NULL) { 366 struct ng_mesg *msg; 367 368 /* Need to send a reset-request */ 369 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE, 370 NGM_MPPC_RESETREQ, 0, M_NOWAIT); 371 if (msg == NULL) 372 return (error); 373 NG_SEND_MSG_ID(error, node, msg, 374 priv->ctrlnode, NULL); 375 } 376 return (error); 377 } 378 NG_FREE_M(m); 379 NG_FWD_NEW_DATA(error, item, priv->recv.hook, out); 380 return (error); 381 } 382 383 /* Oops */ 384 panic("%s: unknown hook", __FUNCTION__); 385} 386 387/* 388 * Destroy node 389 */ 390static int 391ng_mppc_shutdown(node_p node) 392{ 393 const priv_p priv = node->private; 394 395 /* Take down netgraph node */ 396 node->flags |= NG_INVALID; 397#ifdef NETGRAPH_MPPC_COMPRESSION 398 if (priv->xmit.history != NULL) 399 FREE(priv->xmit.history, M_NETGRAPH); 400 if (priv->recv.history != NULL) 401 FREE(priv->recv.history, M_NETGRAPH); 402#endif 403 bzero(priv, sizeof(*priv)); 404 FREE(priv, M_NETGRAPH); 405 node->private = NULL; 406 ng_unref(node); /* let the node escape */ 407 return (0); 408} 409 410/* 411 * Hook disconnection 412 */ 413static int 414ng_mppc_disconnect(hook_p hook) 415{ 416 const node_p node = hook->node; 417 const priv_p priv = node->private; 418 419 /* Zero out hook pointer */ 420 if (hook == priv->xmit.hook) 421 priv->xmit.hook = NULL; 422 if (hook == priv->recv.hook) 423 priv->recv.hook = NULL; 424 425 /* Go away if no longer connected */ 426 if ((node->numhooks == 0) 427 && ((node->flags & NG_INVALID) == 0)) 428 ng_rmnode_self(node); 429 return (0); 430} 431 432/************************************************************************ 433 HELPER STUFF 434 ************************************************************************/ 435 436/* 437 * Compress/encrypt a packet and put the result in a new mbuf at *resultp. 438 * The original mbuf is not free'd. 439 */ 440static int 441ng_mppc_compress(node_p node, struct mbuf *m, struct mbuf **resultp) 442{ 443 const priv_p priv = node->private; 444 struct ng_mppc_dir *const d = &priv->xmit; 445 u_char *inbuf, *outbuf; 446 int outlen, inlen; 447 u_int16_t header; 448 449 /* Initialize */ 450 *resultp = NULL; 451 header = d->cc; 452 if (d->flushed) { 453 header |= MPPC_FLAG_FLUSHED; 454 d->flushed = 0; 455 } 456 457 /* Work with contiguous regions of memory */ 458 inlen = m->m_pkthdr.len; 459 MALLOC(inbuf, u_char *, inlen, M_NETGRAPH, M_NOWAIT); 460 if (inbuf == NULL) 461 return (ENOMEM); 462 m_copydata(m, 0, inlen, (caddr_t)inbuf); 463 if ((d->cfg.bits & MPPC_BIT) != 0) 464 outlen = MPPC_MAX_BLOWUP(inlen); 465 else 466 outlen = MPPC_HDRLEN + inlen; 467 MALLOC(outbuf, u_char *, outlen, M_NETGRAPH, M_NOWAIT); 468 if (outbuf == NULL) { 469 FREE(inbuf, M_NETGRAPH); 470 return (ENOMEM); 471 } 472 473 /* Compress "inbuf" into "outbuf" (if compression enabled) */ 474#ifdef NETGRAPH_MPPC_COMPRESSION 475 if ((d->cfg.bits & MPPC_BIT) != 0) { 476 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS; 477 u_char *source, *dest; 478 u_long sourceCnt, destCnt; 479 int rtn; 480 481 /* Prepare to compress */ 482 source = inbuf; 483 sourceCnt = inlen; 484 dest = outbuf + MPPC_HDRLEN; 485 destCnt = outlen - MPPC_HDRLEN; 486 if ((d->cfg.bits & MPPE_STATELESS) == 0) 487 flags |= MPPC_SAVE_HISTORY; 488 489 /* Compress */ 490 rtn = MPPC_Compress(&source, &dest, &sourceCnt, 491 &destCnt, d->history, flags, 0); 492 493 /* Check return value */ 494 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__)); 495 if ((rtn & MPPC_EXPANDED) == 0 496 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) { 497 outlen -= destCnt; 498 header |= MPPC_FLAG_COMPRESSED; 499 if ((rtn & MPPC_RESTART_HISTORY) != 0) 500 header |= MPPC_FLAG_RESTART; 501 } 502 d->flushed = (rtn & MPPC_EXPANDED) != 0 503 || (flags & MPPC_SAVE_HISTORY) == 0; 504 } 505#endif 506 507 /* If we did not compress this packet, copy it to output buffer */ 508 if ((header & MPPC_FLAG_COMPRESSED) == 0) { 509 bcopy(inbuf, outbuf + MPPC_HDRLEN, inlen); 510 outlen = MPPC_HDRLEN + inlen; 511 } 512 FREE(inbuf, M_NETGRAPH); 513 514 /* Always set the flushed bit in stateless mode */ 515 if ((d->cfg.bits & MPPE_STATELESS) != 0) 516 header |= MPPC_FLAG_FLUSHED; 517 518 /* Now encrypt packet (if encryption enabled) */ 519#ifdef NETGRAPH_MPPC_ENCRYPTION 520 if ((d->cfg.bits & MPPE_BITS) != 0) { 521 522 /* Set header bits; need to reset key if we say we did */ 523 header |= MPPC_FLAG_ENCRYPTED; 524 if ((header & MPPC_FLAG_FLUSHED) != 0) 525 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 526 527 /* Update key if it's time */ 528 if ((d->cfg.bits & MPPE_STATELESS) != 0 529 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 530 ng_mppc_updatekey(d->cfg.bits, 531 d->cfg.startkey, d->key, &d->rc4); 532 } 533 534 /* Encrypt packet */ 535 rc4_crypt(&d->rc4, outbuf + MPPC_HDRLEN, 536 outbuf + MPPC_HDRLEN, outlen - MPPC_HDRLEN); 537 } 538#endif 539 540 /* Update sequence number */ 541 d->cc++; 542 543 /* Install header */ 544 *((u_int16_t *)outbuf) = htons(header); 545 546 /* Return packet in an mbuf */ 547 *resultp = m_devget((caddr_t)outbuf, outlen, 0, NULL, NULL); 548 FREE(outbuf, M_NETGRAPH); 549 return (*resultp == NULL ? ENOBUFS : 0); 550} 551 552/* 553 * Decompress/decrypt packet and put the result in a new mbuf at *resultp. 554 * The original mbuf is not free'd. 555 */ 556static int 557ng_mppc_decompress(node_p node, struct mbuf *m, struct mbuf **resultp) 558{ 559 const priv_p priv = node->private; 560 struct ng_mppc_dir *const d = &priv->recv; 561 u_int16_t header, cc, numLost; 562 u_char *buf; 563 int len; 564 565 /* Pull off header */ 566 if (m->m_pkthdr.len < MPPC_HDRLEN) 567 return (EINVAL); 568 m_copydata(m, 0, MPPC_HDRLEN, (caddr_t)&header); 569 NTOHS(header); 570 cc = (header & MPPC_CCOUNT_MASK); 571 572 /* Copy payload into a contiguous region of memory */ 573 len = m->m_pkthdr.len - MPPC_HDRLEN; 574 MALLOC(buf, u_char *, len, M_NETGRAPH, M_NOWAIT); 575 if (buf == NULL) 576 return (ENOMEM); 577 m_copydata(m, MPPC_HDRLEN, len, (caddr_t)buf); 578 579 /* Check for insane jumps in sequence numbering (D.O.S. attack) */ 580 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 581 if (numLost >= MPPC_INSANE_JUMP) { 582 log(LOG_ERR, "%s: insane jump %d", __FUNCTION__, numLost); 583 priv->recv.cfg.enable = 0; 584 goto failed; 585 } 586 587 /* If flushed bit set, we can always handle packet */ 588 if ((header & MPPC_FLAG_FLUSHED) != 0) { 589#ifdef NETGRAPH_MPPC_COMPRESSION 590 if (d->history != NULL) 591 MPPC_InitDecompressionHistory(d->history); 592#endif 593#ifdef NETGRAPH_MPPC_ENCRYPTION 594 if ((d->cfg.bits & MPPE_BITS) != 0) { 595 596 /* Resync as necessary, skipping lost packets */ 597 while (d->cc != cc) { 598 if ((d->cfg.bits & MPPE_STATELESS) 599 || (d->cc & MPPE_UPDATE_MASK) 600 == MPPE_UPDATE_FLAG) { 601 ng_mppc_updatekey(d->cfg.bits, 602 d->cfg.startkey, d->key, &d->rc4); 603 } 604 d->cc++; 605 } 606 607 /* Reset key (except in stateless mode, see below) */ 608 if ((d->cfg.bits & MPPE_STATELESS) == 0) 609 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 610 } 611#endif 612 d->cc = cc; /* skip over lost seq numbers */ 613 numLost = 0; /* act like no packets were lost */ 614 } 615 616 /* Can't decode non-sequential packets without a flushed bit */ 617 if (numLost != 0) 618 goto failed; 619 620 /* Decrypt packet */ 621 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 622 623 /* Are we not expecting encryption? */ 624 if ((d->cfg.bits & MPPE_BITS) == 0) { 625 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 626 __FUNCTION__, "encrypted"); 627 goto failed; 628 } 629 630#ifdef NETGRAPH_MPPC_ENCRYPTION 631 /* Update key if it's time (always in stateless mode) */ 632 if ((d->cfg.bits & MPPE_STATELESS) != 0 633 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 634 ng_mppc_updatekey(d->cfg.bits, 635 d->cfg.startkey, d->key, &d->rc4); 636 } 637 638 /* Decrypt packet */ 639 rc4_crypt(&d->rc4, buf, buf, len); 640#endif 641 } else { 642 643 /* Are we expecting encryption? */ 644 if ((d->cfg.bits & MPPE_BITS) != 0) { 645 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 646 __FUNCTION__, "unencrypted"); 647 goto failed; 648 } 649 } 650 651 /* Update coherency count for next time (12 bit arithmetic) */ 652 d->cc++; 653 654 /* Check for unexpected compressed packet */ 655 if ((header & MPPC_FLAG_COMPRESSED) != 0 656 && (d->cfg.bits & MPPC_BIT) == 0) { 657 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 658 __FUNCTION__, "compressed"); 659failed: 660 FREE(buf, M_NETGRAPH); 661 return (EINVAL); 662 } 663 664#ifdef NETGRAPH_MPPC_COMPRESSION 665 /* Decompress packet */ 666 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 667 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 668 u_char *decompbuf, *source, *dest; 669 u_long sourceCnt, destCnt; 670 int decomplen, rtn; 671 672 /* Allocate a buffer for decompressed data */ 673 MALLOC(decompbuf, u_char *, MPPC_DECOMP_BUFSIZE 674 + MPPC_DECOMP_SAFETY, M_NETGRAPH, M_NOWAIT); 675 if (decompbuf == NULL) { 676 FREE(buf, M_NETGRAPH); 677 return (ENOMEM); 678 } 679 decomplen = MPPC_DECOMP_BUFSIZE; 680 681 /* Prepare to decompress */ 682 source = buf; 683 sourceCnt = len; 684 dest = decompbuf; 685 destCnt = decomplen; 686 if ((header & MPPC_FLAG_RESTART) != 0) 687 flags |= MPPC_RESTART_HISTORY; 688 689 /* Decompress */ 690 rtn = MPPC_Decompress(&source, &dest, 691 &sourceCnt, &destCnt, d->history, flags); 692 693 /* Check return value */ 694 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__)); 695 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 696 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 697 log(LOG_ERR, "%s: decomp returned 0x%x", 698 __FUNCTION__, rtn); 699 FREE(decompbuf, M_NETGRAPH); 700 goto failed; 701 } 702 703 /* Replace compressed data with decompressed data */ 704 FREE(buf, M_NETGRAPH); 705 buf = decompbuf; 706 len = decomplen - destCnt; 707 } 708#endif 709 710 /* Return result in an mbuf */ 711 *resultp = m_devget((caddr_t)buf, len, 0, NULL, NULL); 712 FREE(buf, M_NETGRAPH); 713 return (*resultp == NULL ? ENOBUFS : 0); 714} 715 716/* 717 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 718 */ 719static void 720ng_mppc_reset_req(node_p node) 721{ 722 const priv_p priv = node->private; 723 struct ng_mppc_dir *const d = &priv->xmit; 724 725#ifdef NETGRAPH_MPPC_COMPRESSION 726 if (d->history != NULL) 727 MPPC_InitCompressionHistory(d->history); 728#endif 729#ifdef NETGRAPH_MPPC_ENCRYPTION 730 if ((d->cfg.bits & MPPE_STATELESS) == 0) 731 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 732#endif 733 d->flushed = 1; 734} 735 736/* 737 * Generate a new encryption key 738 */ 739static void 740ng_mppc_getkey(const u_char *h, u_char *h2, int len) 741{ 742 static const u_char pad1[10] = 743 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 744 static const u_char pad2[10] = 745 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 746 u_char hash[20]; 747 SHA1_CTX c; 748 int k; 749 750 bzero(&hash, sizeof(hash)); 751 SHA1Init(&c); 752 SHA1Update(&c, h, len); 753 for (k = 0; k < 4; k++) 754 SHA1Update(&c, pad1, sizeof(pad2)); 755 SHA1Update(&c, h2, len); 756 for (k = 0; k < 4; k++) 757 SHA1Update(&c, pad2, sizeof(pad2)); 758 SHA1Final(hash, &c); 759 bcopy(hash, h2, len); 760} 761 762/* 763 * Update the encryption key 764 */ 765static void 766ng_mppc_updatekey(u_int32_t bits, 767 u_char *key0, u_char *key, struct rc4_state *rc4) 768{ 769 const int keylen = KEYLEN(bits); 770 771 ng_mppc_getkey(key0, key, keylen); 772 rc4_init(rc4, key, keylen); 773 rc4_crypt(rc4, key, key, keylen); 774 if ((bits & MPPE_128) == 0) 775 bcopy(&ng_mppe_weakenkey, key, sizeof(ng_mppe_weakenkey)); 776 rc4_init(rc4, key, keylen); 777} 778 779