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: src/sys/netgraph/ng_mppc.c,v 1.31 2007/05/18 15:28:01 mav Exp $ 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 <netgraph7/ng_message.h> 60 #include <netgraph7/netgraph.h> 61 #include "ng_mppc.h" 62 63 #include "opt_netgraph.h" 64 65 #if !defined(NETGRAPH7_MPPC_COMPRESSION) && !defined(NETGRAPH7_MPPC_ENCRYPTION) 66 #ifdef KLD_MODULE 67 /* XXX NETGRAPH7_MPPC_COMPRESSION isn't functional yet */ 68 #define NETGRAPH7_MPPC_ENCRYPTION 69 #else 70 /* This case is indicative of an error in sys/conf files */ 71 #error Need either NETGRAPH7_MPPC_COMPRESSION or NETGRAPH7_MPPC_ENCRYPTION 72 #endif 73 #endif 74 75 #ifdef NG_SEPARATE_MALLOC 76 MALLOC_DEFINE(M_NETGRAPH_MPPC, "netgraph_mppc", "netgraph mppc node "); 77 #else 78 #define M_NETGRAPH_MPPC M_NETGRAPH 79 #endif 80 81 #ifdef NETGRAPH7_MPPC_COMPRESSION 82 /* XXX this file doesn't exist yet, but hopefully someday it will... */ 83 #include <net/mppc.h> 84 #endif 85 #ifdef NETGRAPH7_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 */ 125 struct 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 NETGRAPH7_MPPC_COMPRESSION 131 u_char *history; /* compression history */ 132 #endif 133 #ifdef NETGRAPH7_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 */ 140 struct 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 }; 145 typedef struct ng_mppc_private *priv_p; 146 147 /* Netgraph node methods */ 148 static ng_constructor_t ng_mppc_constructor; 149 static ng_rcvmsg_t ng_mppc_rcvmsg; 150 static ng_shutdown_t ng_mppc_shutdown; 151 static ng_newhook_t ng_mppc_newhook; 152 static ng_rcvdata_t ng_mppc_rcvdata; 153 static ng_disconnect_t ng_mppc_disconnect; 154 155 /* Helper functions */ 156 static int ng_mppc_compress(node_p node, 157 struct mbuf **datap); 158 static int ng_mppc_decompress(node_p node, 159 struct mbuf **datap); 160 #ifdef NETGRAPH7_MPPC_ENCRYPTION 161 static void ng_mppc_getkey(const u_char *h, u_char *h2, int len); 162 static void ng_mppc_updatekey(u_int32_t bits, 163 u_char *key0, u_char *key, struct rc4_state *rc4); 164 #endif 165 static void ng_mppc_reset_req(node_p node); 166 167 /* Node type descriptor */ 168 static 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 }; 178 NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 179 180 #ifdef NETGRAPH7_MPPC_ENCRYPTION 181 /* Depend on separate rc4 module */ 182 MODULE_DEPEND(ng_mppc, rc4, 1, 1, 1); 183 #endif 184 185 /* Fixed bit pattern to weaken keysize down to 40 or 56 bits */ 186 static 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 */ 197 static int 198 ng_mppc_constructor(node_p node) 199 { 200 priv_p priv; 201 202 /* Allocate private structure */ 203 priv = kmalloc(sizeof(*priv), M_NETGRAPH_MPPC, 204 M_WAITOK | M_NULLOK | M_ZERO); 205 if (priv == NULL) 206 return (ENOMEM); 207 208 NG_NODE_SET_PRIVATE(node, priv); 209 210 /* This node is not thread safe. */ 211 NG_NODE_FORCE_WRITER(node); 212 213 /* Done */ 214 return (0); 215 } 216 217 /* 218 * Give our OK for a hook to be added 219 */ 220 static int 221 ng_mppc_newhook(node_p node, hook_p hook, const char *name) 222 { 223 const priv_p priv = NG_NODE_PRIVATE(node); 224 hook_p *hookPtr; 225 226 /* Check hook name */ 227 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0) 228 hookPtr = &priv->xmit.hook; 229 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0) 230 hookPtr = &priv->recv.hook; 231 else 232 return (EINVAL); 233 234 /* See if already connected */ 235 if (*hookPtr != NULL) 236 return (EISCONN); 237 238 /* OK */ 239 *hookPtr = hook; 240 return (0); 241 } 242 243 /* 244 * Receive a control message 245 */ 246 static int 247 ng_mppc_rcvmsg(node_p node, item_p item, hook_p lasthook) 248 { 249 const priv_p priv = NG_NODE_PRIVATE(node); 250 struct ng_mesg *resp = NULL; 251 int error = 0; 252 struct ng_mesg *msg; 253 254 NGI_GET_MSG(item, msg); 255 switch (msg->header.typecookie) { 256 case NGM_MPPC_COOKIE: 257 switch (msg->header.cmd) { 258 case NGM_MPPC_CONFIG_COMP: 259 case NGM_MPPC_CONFIG_DECOMP: 260 { 261 struct ng_mppc_config *const cfg 262 = (struct ng_mppc_config *)msg->data; 263 const int isComp = 264 msg->header.cmd == NGM_MPPC_CONFIG_COMP; 265 struct ng_mppc_dir *const d = isComp ? 266 &priv->xmit : &priv->recv; 267 268 /* Check configuration */ 269 if (msg->header.arglen != sizeof(*cfg)) 270 ERROUT(EINVAL); 271 if (cfg->enable) { 272 if ((cfg->bits & ~MPPC_VALID_BITS) != 0) 273 ERROUT(EINVAL); 274 #ifndef NETGRAPH7_MPPC_COMPRESSION 275 if ((cfg->bits & MPPC_BIT) != 0) 276 ERROUT(EPROTONOSUPPORT); 277 #endif 278 #ifndef NETGRAPH7_MPPC_ENCRYPTION 279 if ((cfg->bits & MPPE_BITS) != 0) 280 ERROUT(EPROTONOSUPPORT); 281 #endif 282 } else 283 cfg->bits = 0; 284 285 /* Save return address so we can send reset-req's */ 286 if (!isComp) 287 priv->ctrlnode = NGI_RETADDR(item); 288 289 /* Configuration is OK, reset to it */ 290 d->cfg = *cfg; 291 292 #ifdef NETGRAPH7_MPPC_COMPRESSION 293 /* Initialize state buffers for compression */ 294 if (d->history != NULL) { 295 kfree(d->history, M_NETGRAPH_MPPC); 296 d->history = NULL; 297 } 298 if ((cfg->bits & MPPC_BIT) != 0) { 299 d->history = kmalloc(isComp ? MPPC_SizeOfCompressionHistory() : MPPC_SizeOfDecompressionHistory(), 300 M_NETGRAPH_MPPC, 301 M_WAITOK | M_NULLOK); 302 if (d->history == NULL) 303 ERROUT(ENOMEM); 304 if (isComp) 305 MPPC_InitCompressionHistory(d->history); 306 else { 307 MPPC_InitDecompressionHistory( 308 d->history); 309 } 310 } 311 #endif 312 313 #ifdef NETGRAPH7_MPPC_ENCRYPTION 314 /* Generate initial session keys for encryption */ 315 if ((cfg->bits & MPPE_BITS) != 0) { 316 const int keylen = KEYLEN(cfg->bits); 317 318 bcopy(cfg->startkey, d->key, keylen); 319 ng_mppc_getkey(cfg->startkey, d->key, keylen); 320 if ((cfg->bits & MPPE_40) != 0) 321 bcopy(&ng_mppe_weakenkey, d->key, 3); 322 else if ((cfg->bits & MPPE_56) != 0) 323 bcopy(&ng_mppe_weakenkey, d->key, 1); 324 rc4_init(&d->rc4, d->key, keylen); 325 } 326 #endif 327 328 /* Initialize other state */ 329 d->cc = 0; 330 d->flushed = 0; 331 break; 332 } 333 334 case NGM_MPPC_RESETREQ: 335 ng_mppc_reset_req(node); 336 break; 337 338 default: 339 error = EINVAL; 340 break; 341 } 342 break; 343 default: 344 error = EINVAL; 345 break; 346 } 347 done: 348 NG_RESPOND_MSG(error, node, item, resp); 349 NG_FREE_MSG(msg); 350 return (error); 351 } 352 353 /* 354 * Receive incoming data on our hook. 355 */ 356 static int 357 ng_mppc_rcvdata(hook_p hook, item_p item) 358 { 359 const node_p node = NG_HOOK_NODE(hook); 360 const priv_p priv = NG_NODE_PRIVATE(node); 361 int error; 362 struct mbuf *m; 363 364 NGI_GET_M(item, m); 365 /* Compress and/or encrypt */ 366 if (hook == priv->xmit.hook) { 367 if (!priv->xmit.cfg.enable) { 368 NG_FREE_M(m); 369 NG_FREE_ITEM(item); 370 return (ENXIO); 371 } 372 if ((error = ng_mppc_compress(node, &m)) != 0) { 373 NG_FREE_ITEM(item); 374 return(error); 375 } 376 NG_FWD_NEW_DATA(error, item, priv->xmit.hook, m); 377 return (error); 378 } 379 380 /* Decompress and/or decrypt */ 381 if (hook == priv->recv.hook) { 382 if (!priv->recv.cfg.enable) { 383 NG_FREE_M(m); 384 NG_FREE_ITEM(item); 385 return (ENXIO); 386 } 387 if ((error = ng_mppc_decompress(node, &m)) != 0) { 388 NG_FREE_ITEM(item); 389 if (error == EINVAL && priv->ctrlnode != 0) { 390 struct ng_mesg *msg; 391 392 /* Need to send a reset-request */ 393 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE, 394 NGM_MPPC_RESETREQ, 0, M_WAITOK | M_NULLOK); 395 if (msg == NULL) 396 return (error); 397 NG_SEND_MSG_ID(error, node, msg, 398 priv->ctrlnode, 0); 399 } 400 return (error); 401 } 402 NG_FWD_NEW_DATA(error, item, priv->recv.hook, m); 403 return (error); 404 } 405 406 /* Oops */ 407 panic("%s: unknown hook", __func__); 408 #ifdef RESTARTABLE_PANICS 409 return (EINVAL); 410 #endif 411 } 412 413 /* 414 * Destroy node 415 */ 416 static int 417 ng_mppc_shutdown(node_p node) 418 { 419 const priv_p priv = NG_NODE_PRIVATE(node); 420 421 /* Take down netgraph node */ 422 #ifdef NETGRAPH7_MPPC_COMPRESSION 423 if (priv->xmit.history != NULL) 424 kfree(priv->xmit.history, M_NETGRAPH_MPPC); 425 if (priv->recv.history != NULL) 426 kfree(priv->recv.history, M_NETGRAPH_MPPC); 427 #endif 428 bzero(priv, sizeof(*priv)); 429 kfree(priv, M_NETGRAPH_MPPC); 430 NG_NODE_SET_PRIVATE(node, NULL); 431 NG_NODE_UNREF(node); /* let the node escape */ 432 return (0); 433 } 434 435 /* 436 * Hook disconnection 437 */ 438 static int 439 ng_mppc_disconnect(hook_p hook) 440 { 441 const node_p node = NG_HOOK_NODE(hook); 442 const priv_p priv = NG_NODE_PRIVATE(node); 443 444 /* Zero out hook pointer */ 445 if (hook == priv->xmit.hook) 446 priv->xmit.hook = NULL; 447 if (hook == priv->recv.hook) 448 priv->recv.hook = NULL; 449 450 /* Go away if no longer connected */ 451 if ((NG_NODE_NUMHOOKS(node) == 0) 452 && NG_NODE_IS_VALID(node)) 453 ng_rmnode_self(node); 454 return (0); 455 } 456 457 /************************************************************************ 458 HELPER STUFF 459 ************************************************************************/ 460 461 /* 462 * Compress/encrypt a packet and put the result in a new mbuf at *resultp. 463 * The original mbuf is not free'd. 464 */ 465 static int 466 ng_mppc_compress(node_p node, struct mbuf **datap) 467 { 468 const priv_p priv = NG_NODE_PRIVATE(node); 469 struct ng_mppc_dir *const d = &priv->xmit; 470 u_int16_t header; 471 struct mbuf *m = *datap; 472 473 /* Initialize */ 474 header = d->cc; 475 476 /* Always set the flushed bit in stateless mode */ 477 if (d->flushed || ((d->cfg.bits & MPPE_STATELESS) != 0)) { 478 header |= MPPC_FLAG_FLUSHED; 479 d->flushed = 0; 480 } 481 482 /* Compress packet (if compression enabled) */ 483 #ifdef NETGRAPH7_MPPC_COMPRESSION 484 if ((d->cfg.bits & MPPC_BIT) != 0) { 485 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS; 486 u_char *inbuf, *outbuf; 487 int outlen, inlen; 488 u_char *source, *dest; 489 u_long sourceCnt, destCnt; 490 int rtn; 491 492 /* Work with contiguous regions of memory. */ 493 inlen = m->m_pkthdr.len; 494 inbuf = kmalloc(inlen, M_NETGRAPH_MPPC, M_WAITOK | M_NULLOK); 495 if (inbuf == NULL) { 496 m_freem(m); 497 return (ENOMEM); 498 } 499 m_copydata(m, 0, inlen, inbuf); 500 501 outlen = MPPC_MAX_BLOWUP(inlen); 502 outbuf = kmalloc(outlen, M_NETGRAPH_MPPC, M_WAITOK | M_NULLOK); 503 if (outbuf == NULL) { 504 m_freem(m); 505 kfree(inbuf, M_NETGRAPH_MPPC); 506 return (ENOMEM); 507 } 508 509 /* Prepare to compress */ 510 source = inbuf; 511 sourceCnt = inlen; 512 dest = outbuf; 513 destCnt = outlen; 514 if ((d->cfg.bits & MPPE_STATELESS) == 0) 515 flags |= MPPC_SAVE_HISTORY; 516 517 /* Compress */ 518 rtn = MPPC_Compress(&source, &dest, &sourceCnt, 519 &destCnt, d->history, flags, 0); 520 521 /* Check return value */ 522 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 523 if ((rtn & MPPC_EXPANDED) == 0 524 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) { 525 outlen -= destCnt; 526 header |= MPPC_FLAG_COMPRESSED; 527 if ((rtn & MPPC_RESTART_HISTORY) != 0) 528 header |= MPPC_FLAG_RESTART; 529 530 /* Replace m by the compresed one. */ 531 m_freem(m); 532 m = m_devget(outbuf, outlen, 0, NULL); 533 } 534 d->flushed = (rtn & MPPC_EXPANDED) != 0 535 || (flags & MPPC_SAVE_HISTORY) == 0; 536 537 kfree(inbuf, M_NETGRAPH_MPPC); 538 kfree(outbuf, M_NETGRAPH_MPPC); 539 540 /* Check m_devget() result. */ 541 if (m == NULL) 542 return (ENOMEM); 543 } 544 #endif 545 546 /* Now encrypt packet (if encryption enabled) */ 547 #ifdef NETGRAPH7_MPPC_ENCRYPTION 548 if ((d->cfg.bits & MPPE_BITS) != 0) { 549 struct mbuf *m1; 550 551 /* Set header bits */ 552 header |= MPPC_FLAG_ENCRYPTED; 553 554 /* Update key if it's time */ 555 if ((d->cfg.bits & MPPE_STATELESS) != 0 556 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 557 ng_mppc_updatekey(d->cfg.bits, 558 d->cfg.startkey, d->key, &d->rc4); 559 } else if ((header & MPPC_FLAG_FLUSHED) != 0) { 560 /* Need to reset key if we say we did 561 and ng_mppc_updatekey wasn't called to do it also. */ 562 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 563 } 564 565 /* We must own the mbuf chain exclusively to modify it. */ 566 m = m_unshare(m, M_NOWAIT); 567 if (m == NULL) 568 return (ENOMEM); 569 570 /* Encrypt packet */ 571 m1 = m; 572 while (m1) { 573 rc4_crypt(&d->rc4, mtod(m1, u_char *), 574 mtod(m1, u_char *), m1->m_len); 575 m1 = m1->m_next; 576 } 577 } 578 #endif 579 580 /* Update coherency count for next time (12 bit arithmetic) */ 581 MPPC_CCOUNT_INC(d->cc); 582 583 /* Install header */ 584 M_PREPEND(m, MPPC_HDRLEN, M_NOWAIT); 585 if (m != NULL) 586 *(mtod(m, uint16_t *)) = htons(header); 587 588 *datap = m; 589 return (*datap == NULL ? ENOBUFS : 0); 590 } 591 592 /* 593 * Decompress/decrypt packet and put the result in a new mbuf at *resultp. 594 * The original mbuf is not free'd. 595 */ 596 static int 597 ng_mppc_decompress(node_p node, struct mbuf **datap) 598 { 599 const priv_p priv = NG_NODE_PRIVATE(node); 600 struct ng_mppc_dir *const d = &priv->recv; 601 u_int16_t header, cc; 602 u_int numLost; 603 struct mbuf *m = *datap; 604 605 /* Pull off header */ 606 if (m->m_pkthdr.len < MPPC_HDRLEN) { 607 m_freem(m); 608 return (EINVAL); 609 } 610 m_copydata(m, 0, MPPC_HDRLEN, &header); 611 header = ntohs(header); 612 cc = (header & MPPC_CCOUNT_MASK); 613 m_adj(m, MPPC_HDRLEN); 614 615 /* Check for an unexpected jump in the sequence number */ 616 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 617 618 /* If flushed bit set, we can always handle packet */ 619 if ((header & MPPC_FLAG_FLUSHED) != 0) { 620 #ifdef NETGRAPH7_MPPC_COMPRESSION 621 if (d->history != NULL) 622 MPPC_InitDecompressionHistory(d->history); 623 #endif 624 #ifdef NETGRAPH7_MPPC_ENCRYPTION 625 if ((d->cfg.bits & MPPE_BITS) != 0) { 626 u_int rekey; 627 628 /* How many times are we going to have to re-key? */ 629 rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ? 630 numLost : (numLost / (MPPE_UPDATE_MASK + 1)); 631 if (rekey > MPPE_MAX_REKEY) { 632 log(LOG_ERR, "%s: too many (%d) packets" 633 " dropped, disabling node %p!", 634 __func__, numLost, node); 635 priv->recv.cfg.enable = 0; 636 goto failed; 637 } 638 639 /* Re-key as necessary to catch up to peer */ 640 while (d->cc != cc) { 641 if ((d->cfg.bits & MPPE_STATELESS) != 0 642 || (d->cc & MPPE_UPDATE_MASK) 643 == MPPE_UPDATE_FLAG) { 644 ng_mppc_updatekey(d->cfg.bits, 645 d->cfg.startkey, d->key, &d->rc4); 646 } 647 MPPC_CCOUNT_INC(d->cc); 648 } 649 650 /* Reset key (except in stateless mode, see below) */ 651 if ((d->cfg.bits & MPPE_STATELESS) == 0) 652 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 653 } 654 #endif 655 d->cc = cc; /* skip over lost seq numbers */ 656 numLost = 0; /* act like no packets were lost */ 657 } 658 659 /* Can't decode non-sequential packets without a flushed bit */ 660 if (numLost != 0) 661 goto failed; 662 663 /* Decrypt packet */ 664 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 665 #ifdef NETGRAPH7_MPPC_ENCRYPTION 666 struct mbuf *m1; 667 #endif 668 669 /* Are we not expecting encryption? */ 670 if ((d->cfg.bits & MPPE_BITS) == 0) { 671 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 672 __func__, "encrypted"); 673 goto failed; 674 } 675 676 #ifdef NETGRAPH7_MPPC_ENCRYPTION 677 /* Update key if it's time (always in stateless mode) */ 678 if ((d->cfg.bits & MPPE_STATELESS) != 0 679 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 680 ng_mppc_updatekey(d->cfg.bits, 681 d->cfg.startkey, d->key, &d->rc4); 682 } 683 684 /* We must own the mbuf chain exclusively to modify it. */ 685 m = m_unshare(m, M_NOWAIT); 686 if (m == NULL) 687 return (ENOMEM); 688 689 /* Decrypt packet */ 690 m1 = m; 691 while (m1 != NULL) { 692 rc4_crypt(&d->rc4, mtod(m1, u_char *), 693 mtod(m1, u_char *), m1->m_len); 694 m1 = m1->m_next; 695 } 696 #endif 697 } else { 698 699 /* Are we expecting encryption? */ 700 if ((d->cfg.bits & MPPE_BITS) != 0) { 701 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 702 __func__, "unencrypted"); 703 goto failed; 704 } 705 } 706 707 /* Update coherency count for next time (12 bit arithmetic) */ 708 MPPC_CCOUNT_INC(d->cc); 709 710 /* Check for unexpected compressed packet */ 711 if ((header & MPPC_FLAG_COMPRESSED) != 0 712 && (d->cfg.bits & MPPC_BIT) == 0) { 713 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 714 __func__, "compressed"); 715 failed: 716 m_freem(m); 717 return (EINVAL); 718 } 719 720 #ifdef NETGRAPH7_MPPC_COMPRESSION 721 /* Decompress packet */ 722 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 723 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 724 u_char *decompbuf, *source, *dest; 725 u_long sourceCnt, destCnt; 726 int decomplen, rtn; 727 u_char *buf; 728 int len; 729 730 /* Copy payload into a contiguous region of memory. */ 731 len = m->m_pkthdr.len; 732 buf = kmalloc(len, M_NETGRAPH_MPPC, M_WAITOK | M_NULLOK); 733 if (buf == NULL) { 734 m_freem(m); 735 return (ENOMEM); 736 } 737 m_copydata(m, 0, len, buf); 738 739 /* Allocate a buffer for decompressed data */ 740 decompbuf = kmalloc(MPPC_DECOMP_BUFSIZE + MPPC_DECOMP_SAFETY, 741 M_NETGRAPH_MPPC, M_WAITOK | M_NULLOK); 742 if (decompbuf == NULL) { 743 m_freem(m); 744 kfree(buf, M_NETGRAPH_MPPC); 745 return (ENOMEM); 746 } 747 decomplen = MPPC_DECOMP_BUFSIZE; 748 749 /* Prepare to decompress */ 750 source = buf; 751 sourceCnt = len; 752 dest = decompbuf; 753 destCnt = decomplen; 754 if ((header & MPPC_FLAG_RESTART) != 0) 755 flags |= MPPC_RESTART_HISTORY; 756 757 /* Decompress */ 758 rtn = MPPC_Decompress(&source, &dest, 759 &sourceCnt, &destCnt, d->history, flags); 760 761 /* Check return value */ 762 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 763 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 764 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 765 log(LOG_ERR, "%s: decomp returned 0x%x", 766 __func__, rtn); 767 kfree(buf, M_NETGRAPH_MPPC); 768 kfree(decompbuf, M_NETGRAPH_MPPC); 769 goto failed; 770 } 771 772 /* Replace compressed data with decompressed data */ 773 kfree(buf, M_NETGRAPH_MPPC); 774 len = decomplen - destCnt; 775 776 m_freem(m); 777 m = m_devget(decompbuf, len, 0, NULL); 778 kfree(decompbuf, M_NETGRAPH_MPPC); 779 } 780 #endif 781 782 /* Return result in an mbuf */ 783 *datap = m; 784 return (*datap == NULL ? ENOBUFS : 0); 785 } 786 787 /* 788 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 789 */ 790 static void 791 ng_mppc_reset_req(node_p node) 792 { 793 const priv_p priv = NG_NODE_PRIVATE(node); 794 struct ng_mppc_dir *const d = &priv->xmit; 795 796 #ifdef NETGRAPH7_MPPC_COMPRESSION 797 if (d->history != NULL) 798 MPPC_InitCompressionHistory(d->history); 799 #endif 800 #ifdef NETGRAPH7_MPPC_ENCRYPTION 801 if ((d->cfg.bits & MPPE_STATELESS) == 0) 802 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 803 #endif 804 d->flushed = 1; 805 } 806 807 #ifdef NETGRAPH7_MPPC_ENCRYPTION 808 /* 809 * Generate a new encryption key 810 */ 811 static void 812 ng_mppc_getkey(const u_char *h, u_char *h2, int len) 813 { 814 static const u_char pad1[10] = 815 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 816 static const u_char pad2[10] = 817 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 818 u_char hash[20]; 819 SHA1_CTX c; 820 int k; 821 822 SHA1Init(&c); 823 SHA1Update(&c, h, len); 824 for (k = 0; k < 4; k++) 825 SHA1Update(&c, pad1, sizeof(pad1)); 826 SHA1Update(&c, h2, len); 827 for (k = 0; k < 4; k++) 828 SHA1Update(&c, pad2, sizeof(pad2)); 829 SHA1Final(hash, &c); 830 bcopy(hash, h2, len); 831 } 832 833 /* 834 * Update the encryption key 835 */ 836 static void 837 ng_mppc_updatekey(u_int32_t bits, 838 u_char *key0, u_char *key, struct rc4_state *rc4) 839 { 840 const int keylen = KEYLEN(bits); 841 842 ng_mppc_getkey(key0, key, keylen); 843 rc4_init(rc4, key, keylen); 844 rc4_crypt(rc4, key, key, keylen); 845 if ((bits & MPPE_40) != 0) 846 bcopy(&ng_mppe_weakenkey, key, 3); 847 else if ((bits & MPPE_56) != 0) 848 bcopy(&ng_mppe_weakenkey, key, 1); 849 rc4_init(rc4, key, keylen); 850 } 851 #endif 852 853