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: src/sys/netgraph/ng_mppc.c,v 1.1.2.7 2002/12/16 17:58:42 archie Exp $ 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/conf.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 "ng_mppc.h" 62 63 #include "opt_netgraph.h" 64 65 #if !defined(NETGRAPH_MPPC_COMPRESSION) && !defined(NETGRAPH_MPPC_ENCRYPTION) 66 #error Need either NETGRAPH_MPPC_COMPRESSION or NETGRAPH_MPPC_ENCRYPTION 67 #endif 68 69 #ifdef NETGRAPH_MPPC_COMPRESSION 70 /* XXX this file doesn't exist yet, but hopefully someday it will... */ 71 #include <net/mppc.h> 72 #endif 73 #ifdef NETGRAPH_MPPC_ENCRYPTION 74 #include <crypto/rc4/rc4.h> 75 #endif 76 #include <crypto/sha1.h> 77 78 /* Decompression blowup */ 79 #define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */ 80 #define MPPC_DECOMP_SAFETY 100 /* plus this much margin */ 81 82 /* MPPC/MPPE header length */ 83 #define MPPC_HDRLEN 2 84 85 /* Key length */ 86 #define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8) 87 88 /* 89 * When packets are lost with MPPE, we may have to re-key arbitrarily 90 * many times to 'catch up' to the new jumped-ahead sequence number. 91 * Since this can be expensive, we pose a limit on how many re-keyings 92 * we will do at one time to avoid a possible D.O.S. vulnerability. 93 * This should instead be a configurable parameter. 94 */ 95 #define MPPE_MAX_REKEY 1000 96 97 /* MPPC packet header bits */ 98 #define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */ 99 #define MPPC_FLAG_RESTART 0x4000 /* compress history restart */ 100 #define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */ 101 #define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */ 102 #define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */ 103 104 #define MPPE_UPDATE_MASK 0xff /* coherency count when we're */ 105 #define MPPE_UPDATE_FLAG 0xff /* supposed to update key */ 106 107 #define MPPC_COMP_OK 0x05 108 #define MPPC_DECOMP_OK 0x05 109 110 /* Per direction info */ 111 struct ng_mppc_dir { 112 struct ng_mppc_config cfg; /* configuration */ 113 hook_p hook; /* netgraph hook */ 114 u_int16_t cc:12; /* coherency count */ 115 u_char flushed; /* clean history (xmit only) */ 116 #ifdef NETGRAPH_MPPC_COMPRESSION 117 u_char *history; /* compression history */ 118 #endif 119 #ifdef NETGRAPH_MPPC_ENCRYPTION 120 u_char key[MPPE_KEY_LEN]; /* session key */ 121 struct rc4_state rc4; /* rc4 state */ 122 #endif 123 }; 124 125 /* Node private data */ 126 struct ng_mppc_private { 127 struct ng_mppc_dir xmit; /* compress/encrypt config */ 128 struct ng_mppc_dir recv; /* decompress/decrypt config */ 129 char *ctrlpath; /* path to controlling node */ 130 }; 131 typedef struct ng_mppc_private *priv_p; 132 133 /* Netgraph node methods */ 134 static ng_constructor_t ng_mppc_constructor; 135 static ng_rcvmsg_t ng_mppc_rcvmsg; 136 static ng_shutdown_t ng_mppc_rmnode; 137 static ng_newhook_t ng_mppc_newhook; 138 static ng_rcvdata_t ng_mppc_rcvdata; 139 static ng_disconnect_t ng_mppc_disconnect; 140 141 /* Helper functions */ 142 static int ng_mppc_compress(node_p node, 143 struct mbuf *m, struct mbuf **resultp); 144 static int ng_mppc_decompress(node_p node, 145 struct mbuf *m, struct mbuf **resultp); 146 static void ng_mppc_getkey(const u_char *h, u_char *h2, int len); 147 static void ng_mppc_updatekey(u_int32_t bits, 148 u_char *key0, u_char *key, struct rc4_state *rc4); 149 static void ng_mppc_reset_req(node_p node); 150 151 /* Node type descriptor */ 152 static struct ng_type ng_mppc_typestruct = { 153 NG_VERSION, 154 NG_MPPC_NODE_TYPE, 155 NULL, 156 ng_mppc_constructor, 157 ng_mppc_rcvmsg, 158 ng_mppc_rmnode, 159 ng_mppc_newhook, 160 NULL, 161 NULL, 162 ng_mppc_rcvdata, 163 ng_mppc_rcvdata, 164 ng_mppc_disconnect, 165 NULL 166 }; 167 NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 168 169 /* Fixed bit pattern to weaken keysize down to 40 or 56 bits */ 170 static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e }; 171 172 #define ERROUT(x) do { error = (x); goto done; } while (0) 173 174 /************************************************************************ 175 NETGRAPH NODE STUFF 176 ************************************************************************/ 177 178 /* 179 * Node type constructor 180 */ 181 static int 182 ng_mppc_constructor(node_p *nodep) 183 { 184 priv_p priv; 185 int error; 186 187 /* Allocate private structure */ 188 priv = kmalloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO); 189 if (priv == NULL) 190 return (ENOMEM); 191 192 /* Call generic node constructor */ 193 if ((error = ng_make_node_common(&ng_mppc_typestruct, nodep))) { 194 kfree(priv, M_NETGRAPH); 195 return (error); 196 } 197 (*nodep)->private = priv; 198 199 /* Done */ 200 return (0); 201 } 202 203 /* 204 * Give our OK for a hook to be added 205 */ 206 static int 207 ng_mppc_newhook(node_p node, hook_p hook, const char *name) 208 { 209 const priv_p priv = node->private; 210 hook_p *hookPtr; 211 212 /* Check hook name */ 213 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0) 214 hookPtr = &priv->xmit.hook; 215 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0) 216 hookPtr = &priv->recv.hook; 217 else 218 return (EINVAL); 219 220 /* See if already connected */ 221 if (*hookPtr != NULL) 222 return (EISCONN); 223 224 /* OK */ 225 *hookPtr = hook; 226 return (0); 227 } 228 229 /* 230 * Receive a control message 231 */ 232 static int 233 ng_mppc_rcvmsg(node_p node, struct ng_mesg *msg, 234 const char *raddr, struct ng_mesg **rptr) 235 { 236 const priv_p priv = node->private; 237 struct ng_mesg *resp = NULL; 238 int error = 0; 239 240 switch (msg->header.typecookie) { 241 case NGM_MPPC_COOKIE: 242 switch (msg->header.cmd) { 243 case NGM_MPPC_CONFIG_COMP: 244 case NGM_MPPC_CONFIG_DECOMP: 245 { 246 struct ng_mppc_config *const cfg 247 = (struct ng_mppc_config *)msg->data; 248 const int isComp = 249 msg->header.cmd == NGM_MPPC_CONFIG_COMP; 250 struct ng_mppc_dir *const d = isComp ? 251 &priv->xmit : &priv->recv; 252 253 /* Check configuration */ 254 if (msg->header.arglen != sizeof(*cfg)) 255 ERROUT(EINVAL); 256 if (cfg->enable) { 257 if ((cfg->bits & ~MPPC_VALID_BITS) != 0) 258 ERROUT(EINVAL); 259 #ifndef NETGRAPH_MPPC_COMPRESSION 260 if ((cfg->bits & MPPC_BIT) != 0) 261 ERROUT(EPROTONOSUPPORT); 262 #endif 263 #ifndef NETGRAPH_MPPC_ENCRYPTION 264 if ((cfg->bits & MPPE_BITS) != 0) 265 ERROUT(EPROTONOSUPPORT); 266 #endif 267 } else 268 cfg->bits = 0; 269 270 /* Save return address so we can send reset-req's */ 271 if (!isComp && priv->ctrlpath != NULL) { 272 kfree(priv->ctrlpath, M_NETGRAPH); 273 priv->ctrlpath = NULL; 274 } 275 if (!isComp && raddr != NULL) { 276 priv->ctrlpath = kmalloc(strlen(raddr) + 1, 277 M_NETGRAPH, M_NOWAIT); 278 if (priv->ctrlpath == NULL) 279 ERROUT(ENOMEM); 280 strcpy(priv->ctrlpath, raddr); 281 } 282 283 /* Configuration is OK, reset to it */ 284 d->cfg = *cfg; 285 286 #ifdef NETGRAPH_MPPC_COMPRESSION 287 /* Initialize state buffers for compression */ 288 if (d->history != NULL) { 289 kfree(d->history, M_NETGRAPH); 290 d->history = NULL; 291 } 292 if ((cfg->bits & MPPC_BIT) != 0) { 293 d->history = kmalloc(isComp ? MPPC_SizeOfCompressionHistory() : MPPC_SizeOfDecompressionHistory(), 294 M_NETGRAPH, M_NOWAIT); 295 if (d->history == NULL) 296 ERROUT(ENOMEM); 297 if (isComp) 298 MPPC_InitCompressionHistory(d->history); 299 else { 300 MPPC_InitDecompressionHistory( 301 d->history); 302 } 303 } 304 #endif 305 306 #ifdef NETGRAPH_MPPC_ENCRYPTION 307 /* Generate initial session keys for encryption */ 308 if ((cfg->bits & MPPE_BITS) != 0) { 309 const int keylen = KEYLEN(cfg->bits); 310 311 bcopy(cfg->startkey, d->key, keylen); 312 ng_mppc_getkey(cfg->startkey, d->key, keylen); 313 if ((cfg->bits & MPPE_40) != 0) 314 bcopy(&ng_mppe_weakenkey, d->key, 3); 315 else if ((cfg->bits & MPPE_56) != 0) 316 bcopy(&ng_mppe_weakenkey, d->key, 1); 317 rc4_init(&d->rc4, d->key, keylen); 318 } 319 #endif 320 321 /* Initialize other state */ 322 d->cc = 0; 323 d->flushed = 0; 324 break; 325 } 326 327 case NGM_MPPC_RESETREQ: 328 ng_mppc_reset_req(node); 329 break; 330 331 default: 332 error = EINVAL; 333 break; 334 } 335 break; 336 default: 337 error = EINVAL; 338 break; 339 } 340 if (rptr) 341 *rptr = resp; 342 else if (resp) 343 kfree(resp, M_NETGRAPH); 344 345 done: 346 kfree(msg, M_NETGRAPH); 347 return (error); 348 } 349 350 /* 351 * Receive incoming data on our hook. 352 */ 353 static int 354 ng_mppc_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 355 { 356 const node_p node = hook->node; 357 const priv_p priv = node->private; 358 struct mbuf *out; 359 int error; 360 361 /* Compress and/or encrypt */ 362 if (hook == priv->xmit.hook) { 363 if (!priv->xmit.cfg.enable) { 364 NG_FREE_DATA(m, meta); 365 return (ENXIO); 366 } 367 if ((error = ng_mppc_compress(node, m, &out)) != 0) { 368 NG_FREE_DATA(m, meta); 369 return(error); 370 } 371 m_freem(m); 372 NG_SEND_DATA(error, priv->xmit.hook, out, meta); 373 return (error); 374 } 375 376 /* Decompress and/or decrypt */ 377 if (hook == priv->recv.hook) { 378 if (!priv->recv.cfg.enable) { 379 NG_FREE_DATA(m, meta); 380 return (ENXIO); 381 } 382 if ((error = ng_mppc_decompress(node, m, &out)) != 0) { 383 NG_FREE_DATA(m, meta); 384 if (error == EINVAL && priv->ctrlpath != NULL) { 385 struct ng_mesg *msg; 386 387 /* Need to send a reset-request */ 388 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE, 389 NGM_MPPC_RESETREQ, 0, M_NOWAIT); 390 if (msg == NULL) 391 return (error); 392 ng_send_msg(node, msg, priv->ctrlpath, NULL); 393 } 394 return (error); 395 } 396 m_freem(m); 397 NG_SEND_DATA(error, priv->recv.hook, out, meta); 398 return (error); 399 } 400 401 /* Oops */ 402 panic("%s: unknown hook", __func__); 403 } 404 405 /* 406 * Destroy node 407 */ 408 static int 409 ng_mppc_rmnode(node_p node) 410 { 411 const priv_p priv = node->private; 412 413 /* Take down netgraph node */ 414 node->flags |= NG_INVALID; 415 ng_cutlinks(node); 416 ng_unname(node); 417 if (priv->ctrlpath != NULL) 418 kfree(priv->ctrlpath, M_NETGRAPH); 419 #ifdef NETGRAPH_MPPC_COMPRESSION 420 if (priv->xmit.history != NULL) 421 kfree(priv->xmit.history, M_NETGRAPH); 422 if (priv->recv.history != NULL) 423 kfree(priv->recv.history, M_NETGRAPH); 424 #endif 425 bzero(priv, sizeof(*priv)); 426 kfree(priv, M_NETGRAPH); 427 node->private = NULL; 428 ng_unref(node); /* let the node escape */ 429 return (0); 430 } 431 432 /* 433 * Hook disconnection 434 */ 435 static int 436 ng_mppc_disconnect(hook_p hook) 437 { 438 const node_p node = hook->node; 439 const priv_p priv = node->private; 440 441 /* Zero out hook pointer */ 442 if (hook == priv->xmit.hook) 443 priv->xmit.hook = NULL; 444 if (hook == priv->recv.hook) 445 priv->recv.hook = NULL; 446 447 /* Go away if no longer connected */ 448 if (node->numhooks == 0) 449 ng_rmnode(node); 450 return (0); 451 } 452 453 /************************************************************************ 454 HELPER STUFF 455 ************************************************************************/ 456 457 /* 458 * Compress/encrypt a packet and put the result in a new mbuf at *resultp. 459 * The original mbuf is not free'd. 460 */ 461 static int 462 ng_mppc_compress(node_p node, struct mbuf *m, struct mbuf **resultp) 463 { 464 const priv_p priv = node->private; 465 struct ng_mppc_dir *const d = &priv->xmit; 466 u_char *inbuf, *outbuf; 467 int outlen, inlen; 468 u_int16_t header; 469 470 /* Initialize */ 471 *resultp = NULL; 472 header = d->cc; 473 if (d->flushed) { 474 header |= MPPC_FLAG_FLUSHED; 475 d->flushed = 0; 476 } 477 478 /* Work with contiguous regions of memory */ 479 inlen = m->m_pkthdr.len; 480 inbuf = kmalloc(inlen, M_NETGRAPH, M_NOWAIT); 481 if (inbuf == NULL) 482 return (ENOMEM); 483 m_copydata(m, 0, inlen, inbuf); 484 if ((d->cfg.bits & MPPC_BIT) != 0) 485 outlen = MPPC_MAX_BLOWUP(inlen); 486 else 487 outlen = MPPC_HDRLEN + inlen; 488 outbuf = kmalloc(outlen, M_NETGRAPH, M_NOWAIT); 489 if (outbuf == NULL) { 490 kfree(inbuf, M_NETGRAPH); 491 return (ENOMEM); 492 } 493 494 /* Compress "inbuf" into "outbuf" (if compression enabled) */ 495 #ifdef NETGRAPH_MPPC_COMPRESSION 496 if ((d->cfg.bits & MPPC_BIT) != 0) { 497 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS; 498 u_char *source, *dest; 499 u_long sourceCnt, destCnt; 500 int rtn; 501 502 /* Prepare to compress */ 503 source = inbuf; 504 sourceCnt = inlen; 505 dest = outbuf + MPPC_HDRLEN; 506 destCnt = outlen - MPPC_HDRLEN; 507 if ((d->cfg.bits & MPPE_STATELESS) == 0) 508 flags |= MPPC_SAVE_HISTORY; 509 510 /* Compress */ 511 rtn = MPPC_Compress(&source, &dest, &sourceCnt, 512 &destCnt, d->history, flags, 0); 513 514 /* Check return value */ 515 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 516 if ((rtn & MPPC_EXPANDED) == 0 517 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) { 518 outlen -= destCnt; 519 header |= MPPC_FLAG_COMPRESSED; 520 if ((rtn & MPPC_RESTART_HISTORY) != 0) 521 header |= MPPC_FLAG_RESTART; 522 } 523 d->flushed = (rtn & MPPC_EXPANDED) != 0 524 || (flags & MPPC_SAVE_HISTORY) == 0; 525 } 526 #endif 527 528 /* If we did not compress this packet, copy it to output buffer */ 529 if ((header & MPPC_FLAG_COMPRESSED) == 0) { 530 bcopy(inbuf, outbuf + MPPC_HDRLEN, inlen); 531 outlen = MPPC_HDRLEN + inlen; 532 } 533 kfree(inbuf, M_NETGRAPH); 534 535 /* Always set the flushed bit in stateless mode */ 536 if ((d->cfg.bits & MPPE_STATELESS) != 0) 537 header |= MPPC_FLAG_FLUSHED; 538 539 /* Now encrypt packet (if encryption enabled) */ 540 #ifdef NETGRAPH_MPPC_ENCRYPTION 541 if ((d->cfg.bits & MPPE_BITS) != 0) { 542 543 /* Set header bits; need to reset key if we say we did */ 544 header |= MPPC_FLAG_ENCRYPTED; 545 if ((header & MPPC_FLAG_FLUSHED) != 0) 546 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 547 548 /* Update key if it's time */ 549 if ((d->cfg.bits & MPPE_STATELESS) != 0 550 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 551 ng_mppc_updatekey(d->cfg.bits, 552 d->cfg.startkey, d->key, &d->rc4); 553 } 554 555 /* Encrypt packet */ 556 rc4_crypt(&d->rc4, outbuf + MPPC_HDRLEN, 557 outbuf + MPPC_HDRLEN, outlen - MPPC_HDRLEN); 558 } 559 #endif 560 561 /* Update sequence number */ 562 d->cc++; 563 564 /* Install header */ 565 *((u_int16_t *)outbuf) = htons(header); 566 567 /* Return packet in an mbuf */ 568 *resultp = m_devget(outbuf, outlen, 0, NULL); 569 kfree(outbuf, M_NETGRAPH); 570 return (*resultp == NULL ? ENOBUFS : 0); 571 } 572 573 /* 574 * Decompress/decrypt packet and put the result in a new mbuf at *resultp. 575 * The original mbuf is not free'd. 576 */ 577 static int 578 ng_mppc_decompress(node_p node, struct mbuf *m, struct mbuf **resultp) 579 { 580 const priv_p priv = node->private; 581 struct ng_mppc_dir *const d = &priv->recv; 582 u_int16_t header, cc; 583 u_int numLost; 584 u_char *buf; 585 int len; 586 587 /* Pull off header */ 588 if (m->m_pkthdr.len < MPPC_HDRLEN) 589 return (EINVAL); 590 m_copydata(m, 0, MPPC_HDRLEN, &header); 591 header = ntohs(header); 592 cc = (header & MPPC_CCOUNT_MASK); 593 594 /* Copy payload into a contiguous region of memory */ 595 len = m->m_pkthdr.len - MPPC_HDRLEN; 596 buf = kmalloc(len, M_NETGRAPH, M_NOWAIT); 597 if (buf == NULL) 598 return (ENOMEM); 599 m_copydata(m, MPPC_HDRLEN, len, buf); 600 601 /* Check for an unexpected jump in the sequence number */ 602 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 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 u_int rekey; 613 614 /* How many times are we going to have to re-key? */ 615 rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ? 616 numLost : (numLost / (MPPE_UPDATE_MASK + 1)); 617 if (rekey > MPPE_MAX_REKEY) { 618 log(LOG_ERR, "%s: too many (%d) packets" 619 " dropped, disabling node %p!", 620 __func__, numLost, node); 621 priv->recv.cfg.enable = 0; 622 goto failed; 623 } 624 625 /* Re-key as necessary to catch up to peer */ 626 while (d->cc != cc) { 627 if ((d->cfg.bits & MPPE_STATELESS) != 0 628 || (d->cc & MPPE_UPDATE_MASK) 629 == MPPE_UPDATE_FLAG) { 630 ng_mppc_updatekey(d->cfg.bits, 631 d->cfg.startkey, d->key, &d->rc4); 632 } 633 d->cc++; 634 } 635 636 /* Reset key (except in stateless mode, see below) */ 637 if ((d->cfg.bits & MPPE_STATELESS) == 0) 638 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 639 } 640 #endif 641 d->cc = cc; /* skip over lost seq numbers */ 642 numLost = 0; /* act like no packets were lost */ 643 } 644 645 /* Can't decode non-sequential packets without a flushed bit */ 646 if (numLost != 0) 647 goto failed; 648 649 /* Decrypt packet */ 650 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 651 652 /* Are we not expecting encryption? */ 653 if ((d->cfg.bits & MPPE_BITS) == 0) { 654 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 655 __func__, "encrypted"); 656 goto failed; 657 } 658 659 #ifdef NETGRAPH_MPPC_ENCRYPTION 660 /* Update key if it's time (always in stateless mode) */ 661 if ((d->cfg.bits & MPPE_STATELESS) != 0 662 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 663 ng_mppc_updatekey(d->cfg.bits, 664 d->cfg.startkey, d->key, &d->rc4); 665 } 666 667 /* Decrypt packet */ 668 rc4_crypt(&d->rc4, buf, buf, len); 669 #endif 670 } else { 671 672 /* Are we expecting encryption? */ 673 if ((d->cfg.bits & MPPE_BITS) != 0) { 674 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 675 __func__, "unencrypted"); 676 goto failed; 677 } 678 } 679 680 /* Update coherency count for next time (12 bit arithmetic) */ 681 d->cc++; 682 683 /* Check for unexpected compressed packet */ 684 if ((header & MPPC_FLAG_COMPRESSED) != 0 685 && (d->cfg.bits & MPPC_BIT) == 0) { 686 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 687 __func__, "compressed"); 688 failed: 689 kfree(buf, M_NETGRAPH); 690 return (EINVAL); 691 } 692 693 #ifdef NETGRAPH_MPPC_COMPRESSION 694 /* Decompress packet */ 695 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 696 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 697 u_char *decompbuf, *source, *dest; 698 u_long sourceCnt, destCnt; 699 int decomplen, rtn; 700 701 /* Allocate a buffer for decompressed data */ 702 decompbuf = kmalloc(MPPC_DECOMP_BUFSIZE + MPPC_DECOMP_SAFETY, 703 M_NETGRAPH, M_NOWAIT); 704 if (decompbuf == NULL) { 705 kfree(buf, M_NETGRAPH); 706 return (ENOMEM); 707 } 708 decomplen = MPPC_DECOMP_BUFSIZE; 709 710 /* Prepare to decompress */ 711 source = buf; 712 sourceCnt = len; 713 dest = decompbuf; 714 destCnt = decomplen; 715 if ((header & MPPC_FLAG_RESTART) != 0) 716 flags |= MPPC_RESTART_HISTORY; 717 718 /* Decompress */ 719 rtn = MPPC_Decompress(&source, &dest, 720 &sourceCnt, &destCnt, d->history, flags); 721 722 /* Check return value */ 723 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 724 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 725 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 726 log(LOG_ERR, "%s: decomp returned 0x%x", 727 __func__, rtn); 728 kfree(decompbuf, M_NETGRAPH); 729 goto failed; 730 } 731 732 /* Replace compressed data with decompressed data */ 733 kfree(buf, M_NETGRAPH); 734 buf = decompbuf; 735 len = decomplen - destCnt; 736 } 737 #endif 738 739 /* Return result in an mbuf */ 740 *resultp = m_devget(buf, len, 0, NULL); 741 kfree(buf, M_NETGRAPH); 742 return (*resultp == NULL ? ENOBUFS : 0); 743 } 744 745 /* 746 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 747 */ 748 static void 749 ng_mppc_reset_req(node_p node) 750 { 751 const priv_p priv = node->private; 752 struct ng_mppc_dir *const d = &priv->xmit; 753 754 #ifdef NETGRAPH_MPPC_COMPRESSION 755 if (d->history != NULL) 756 MPPC_InitCompressionHistory(d->history); 757 #endif 758 #ifdef NETGRAPH_MPPC_ENCRYPTION 759 if ((d->cfg.bits & MPPE_STATELESS) == 0) 760 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 761 #endif 762 d->flushed = 1; 763 } 764 765 /* 766 * Generate a new encryption key 767 */ 768 static void 769 ng_mppc_getkey(const u_char *h, u_char *h2, int len) 770 { 771 static const u_char pad1[10] = 772 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 773 static const u_char pad2[10] = 774 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 775 u_char hash[20]; 776 SHA1_CTX c; 777 int k; 778 779 bzero(&hash, sizeof(hash)); 780 SHA1Init(&c); 781 SHA1Update(&c, h, len); 782 for (k = 0; k < 4; k++) 783 SHA1Update(&c, pad1, sizeof(pad2)); 784 SHA1Update(&c, h2, len); 785 for (k = 0; k < 4; k++) 786 SHA1Update(&c, pad2, sizeof(pad2)); 787 SHA1Final(hash, &c); 788 bcopy(hash, h2, len); 789 } 790 791 /* 792 * Update the encryption key 793 */ 794 static void 795 ng_mppc_updatekey(u_int32_t bits, 796 u_char *key0, u_char *key, struct rc4_state *rc4) 797 { 798 const int keylen = KEYLEN(bits); 799 800 ng_mppc_getkey(key0, key, keylen); 801 rc4_init(rc4, key, keylen); 802 rc4_crypt(rc4, key, key, keylen); 803 if ((bits & MPPE_40) != 0) 804 bcopy(&ng_mppe_weakenkey, key, 3); 805 else if ((bits & MPPE_56) != 0) 806 bcopy(&ng_mppe_weakenkey, key, 1); 807 rc4_init(rc4, key, keylen); 808 } 809 810