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 * $FreeBSD$ 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 NG_SEPARATE_MALLOC 69 MALLOC_DEFINE(M_NETGRAPH_MPPC, "netgraph_mppc", "netgraph mppc node "); 70 #else 71 #define M_NETGRAPH_MPPC M_NETGRAPH 72 #endif 73 74 #ifdef NETGRAPH_MPPC_COMPRESSION 75 /* XXX this file doesn't exist yet, but hopefully someday it will... */ 76 #include <net/mppc.h> 77 #endif 78 #ifdef NETGRAPH_MPPC_ENCRYPTION 79 #include <crypto/rc4/rc4.h> 80 #endif 81 #include <crypto/sha1.h> 82 83 /* Decompression blowup */ 84 #define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */ 85 #define MPPC_DECOMP_SAFETY 100 /* plus this much margin */ 86 87 /* MPPC/MPPE header length */ 88 #define MPPC_HDRLEN 2 89 90 /* Key length */ 91 #define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8) 92 93 /* 94 * When packets are lost with MPPE, we may have to re-key arbitrarily 95 * many times to 'catch up' to the new jumped-ahead sequence number. 96 * Since this can be expensive, we pose a limit on how many re-keyings 97 * we will do at one time to avoid a possible D.O.S. vulnerability. 98 * This should instead be a configurable parameter. 99 */ 100 #define MPPE_MAX_REKEY 1000 101 102 /* MPPC packet header bits */ 103 #define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */ 104 #define MPPC_FLAG_RESTART 0x4000 /* compress history restart */ 105 #define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */ 106 #define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */ 107 #define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */ 108 109 #define MPPE_UPDATE_MASK 0xff /* coherency count when we're */ 110 #define MPPE_UPDATE_FLAG 0xff /* supposed to update key */ 111 112 #define MPPC_COMP_OK 0x05 113 #define MPPC_DECOMP_OK 0x05 114 115 /* Per direction info */ 116 struct ng_mppc_dir { 117 struct ng_mppc_config cfg; /* configuration */ 118 hook_p hook; /* netgraph hook */ 119 u_int16_t cc:12; /* coherency count */ 120 u_char flushed; /* clean history (xmit only) */ 121 #ifdef NETGRAPH_MPPC_COMPRESSION 122 u_char *history; /* compression history */ 123 #endif 124 #ifdef NETGRAPH_MPPC_ENCRYPTION 125 u_char key[MPPE_KEY_LEN]; /* session key */ 126 struct rc4_state rc4; /* rc4 state */ 127 #endif 128 }; 129 130 /* Node private data */ 131 struct ng_mppc_private { 132 struct ng_mppc_dir xmit; /* compress/encrypt config */ 133 struct ng_mppc_dir recv; /* decompress/decrypt config */ 134 ng_ID_t ctrlnode; /* path to controlling node */ 135 }; 136 typedef struct ng_mppc_private *priv_p; 137 138 /* Netgraph node methods */ 139 static ng_constructor_t ng_mppc_constructor; 140 static ng_rcvmsg_t ng_mppc_rcvmsg; 141 static ng_shutdown_t ng_mppc_shutdown; 142 static ng_newhook_t ng_mppc_newhook; 143 static ng_rcvdata_t ng_mppc_rcvdata; 144 static ng_disconnect_t ng_mppc_disconnect; 145 146 /* Helper functions */ 147 static int ng_mppc_compress(node_p node, 148 struct mbuf *m, struct mbuf **resultp); 149 static int ng_mppc_decompress(node_p node, 150 struct mbuf *m, struct mbuf **resultp); 151 static void ng_mppc_getkey(const u_char *h, u_char *h2, int len); 152 static void ng_mppc_updatekey(u_int32_t bits, 153 u_char *key0, u_char *key, struct rc4_state *rc4); 154 static void ng_mppc_reset_req(node_p node); 155 156 /* Node type descriptor */ 157 static struct ng_type ng_mppc_typestruct = { 158 .version = NG_ABI_VERSION, 159 .name = NG_MPPC_NODE_TYPE, 160 .constructor = ng_mppc_constructor, 161 .rcvmsg = ng_mppc_rcvmsg, 162 .shutdown = ng_mppc_shutdown, 163 .newhook = ng_mppc_newhook, 164 .rcvdata = ng_mppc_rcvdata, 165 .disconnect = ng_mppc_disconnect, 166 }; 167 NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 168 169 #ifdef NETGRAPH_MPPC_ENCRYPTION 170 /* Depend on separate rc4 module */ 171 MODULE_DEPEND(ng_mppc, rc4, 1, 1, 1); 172 #endif 173 174 /* Fixed bit pattern to weaken keysize down to 40 or 56 bits */ 175 static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e }; 176 177 #define ERROUT(x) do { error = (x); goto done; } while (0) 178 179 /************************************************************************ 180 NETGRAPH NODE STUFF 181 ************************************************************************/ 182 183 /* 184 * Node type constructor 185 */ 186 static int 187 ng_mppc_constructor(node_p node) 188 { 189 priv_p priv; 190 191 /* Allocate private structure */ 192 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_MPPC, M_NOWAIT | M_ZERO); 193 if (priv == NULL) 194 return (ENOMEM); 195 196 NG_NODE_SET_PRIVATE(node, priv); 197 198 /* Done */ 199 return (0); 200 } 201 202 /* 203 * Give our OK for a hook to be added 204 */ 205 static int 206 ng_mppc_newhook(node_p node, hook_p hook, const char *name) 207 { 208 const priv_p priv = NG_NODE_PRIVATE(node); 209 hook_p *hookPtr; 210 211 /* Check hook name */ 212 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0) 213 hookPtr = &priv->xmit.hook; 214 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0) 215 hookPtr = &priv->recv.hook; 216 else 217 return (EINVAL); 218 219 /* See if already connected */ 220 if (*hookPtr != NULL) 221 return (EISCONN); 222 223 /* OK */ 224 *hookPtr = hook; 225 return (0); 226 } 227 228 /* 229 * Receive a control message 230 */ 231 static int 232 ng_mppc_rcvmsg(node_p node, item_p item, hook_p lasthook) 233 { 234 const priv_p priv = NG_NODE_PRIVATE(node); 235 struct ng_mesg *resp = NULL; 236 int error = 0; 237 struct ng_mesg *msg; 238 239 NGI_GET_MSG(item, msg); 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) 272 priv->ctrlnode = NGI_RETADDR(item); 273 274 /* Configuration is OK, reset to it */ 275 d->cfg = *cfg; 276 277 #ifdef NETGRAPH_MPPC_COMPRESSION 278 /* Initialize state buffers for compression */ 279 if (d->history != NULL) { 280 FREE(d->history, M_NETGRAPH_MPPC); 281 d->history = NULL; 282 } 283 if ((cfg->bits & MPPC_BIT) != 0) { 284 MALLOC(d->history, u_char *, 285 isComp ? MPPC_SizeOfCompressionHistory() : 286 MPPC_SizeOfDecompressionHistory(), 287 M_NETGRAPH_MPPC, M_NOWAIT); 288 if (d->history == NULL) 289 ERROUT(ENOMEM); 290 if (isComp) 291 MPPC_InitCompressionHistory(d->history); 292 else { 293 MPPC_InitDecompressionHistory( 294 d->history); 295 } 296 } 297 #endif 298 299 #ifdef NETGRAPH_MPPC_ENCRYPTION 300 /* Generate initial session keys for encryption */ 301 if ((cfg->bits & MPPE_BITS) != 0) { 302 const int keylen = KEYLEN(cfg->bits); 303 304 bcopy(cfg->startkey, d->key, keylen); 305 ng_mppc_getkey(cfg->startkey, d->key, keylen); 306 if ((cfg->bits & MPPE_40) != 0) 307 bcopy(&ng_mppe_weakenkey, d->key, 3); 308 else if ((cfg->bits & MPPE_56) != 0) 309 bcopy(&ng_mppe_weakenkey, d->key, 1); 310 rc4_init(&d->rc4, d->key, keylen); 311 } 312 #endif 313 314 /* Initialize other state */ 315 d->cc = 0; 316 d->flushed = 0; 317 break; 318 } 319 320 case NGM_MPPC_RESETREQ: 321 ng_mppc_reset_req(node); 322 break; 323 324 default: 325 error = EINVAL; 326 break; 327 } 328 break; 329 default: 330 error = EINVAL; 331 break; 332 } 333 done: 334 NG_RESPOND_MSG(error, node, item, resp); 335 NG_FREE_MSG(msg); 336 return (error); 337 } 338 339 /* 340 * Receive incoming data on our hook. 341 */ 342 static int 343 ng_mppc_rcvdata(hook_p hook, item_p item) 344 { 345 const node_p node = NG_HOOK_NODE(hook); 346 const priv_p priv = NG_NODE_PRIVATE(node); 347 struct mbuf *out; 348 int error; 349 struct mbuf *m; 350 351 NGI_GET_M(item, m); 352 /* Compress and/or encrypt */ 353 if (hook == priv->xmit.hook) { 354 if (!priv->xmit.cfg.enable) { 355 NG_FREE_M(m); 356 NG_FREE_ITEM(item); 357 return (ENXIO); 358 } 359 if ((error = ng_mppc_compress(node, m, &out)) != 0) { 360 NG_FREE_M(m); 361 NG_FREE_ITEM(item); 362 return(error); 363 } 364 NG_FREE_M(m); 365 NG_FWD_NEW_DATA(error, item, priv->xmit.hook, out); 366 return (error); 367 } 368 369 /* Decompress and/or decrypt */ 370 if (hook == priv->recv.hook) { 371 if (!priv->recv.cfg.enable) { 372 NG_FREE_M(m); 373 NG_FREE_ITEM(item); 374 return (ENXIO); 375 } 376 if ((error = ng_mppc_decompress(node, m, &out)) != 0) { 377 NG_FREE_M(m); 378 NG_FREE_ITEM(item); 379 if (error == EINVAL && priv->ctrlnode != 0) { 380 struct ng_mesg *msg; 381 382 /* Need to send a reset-request */ 383 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE, 384 NGM_MPPC_RESETREQ, 0, M_NOWAIT); 385 if (msg == NULL) 386 return (error); 387 NG_SEND_MSG_ID(error, node, msg, 388 priv->ctrlnode, 0); 389 } 390 return (error); 391 } 392 NG_FREE_M(m); 393 NG_FWD_NEW_DATA(error, item, priv->recv.hook, out); 394 return (error); 395 } 396 397 /* Oops */ 398 panic("%s: unknown hook", __func__); 399 #ifdef RESTARTABLE_PANICS 400 return (EINVAL); 401 #endif 402 } 403 404 /* 405 * Destroy node 406 */ 407 static int 408 ng_mppc_shutdown(node_p node) 409 { 410 const priv_p priv = NG_NODE_PRIVATE(node); 411 412 /* Take down netgraph node */ 413 #ifdef NETGRAPH_MPPC_COMPRESSION 414 if (priv->xmit.history != NULL) 415 FREE(priv->xmit.history, M_NETGRAPH_MPPC); 416 if (priv->recv.history != NULL) 417 FREE(priv->recv.history, M_NETGRAPH_MPPC); 418 #endif 419 bzero(priv, sizeof(*priv)); 420 FREE(priv, M_NETGRAPH_MPPC); 421 NG_NODE_SET_PRIVATE(node, NULL); 422 NG_NODE_UNREF(node); /* let the node escape */ 423 return (0); 424 } 425 426 /* 427 * Hook disconnection 428 */ 429 static int 430 ng_mppc_disconnect(hook_p hook) 431 { 432 const node_p node = NG_HOOK_NODE(hook); 433 const priv_p priv = NG_NODE_PRIVATE(node); 434 435 /* Zero out hook pointer */ 436 if (hook == priv->xmit.hook) 437 priv->xmit.hook = NULL; 438 if (hook == priv->recv.hook) 439 priv->recv.hook = NULL; 440 441 /* Go away if no longer connected */ 442 if ((NG_NODE_NUMHOOKS(node) == 0) 443 && NG_NODE_IS_VALID(node)) 444 ng_rmnode_self(node); 445 return (0); 446 } 447 448 /************************************************************************ 449 HELPER STUFF 450 ************************************************************************/ 451 452 /* 453 * Compress/encrypt a packet and put the result in a new mbuf at *resultp. 454 * The original mbuf is not free'd. 455 */ 456 static int 457 ng_mppc_compress(node_p node, struct mbuf *m, struct mbuf **resultp) 458 { 459 const priv_p priv = NG_NODE_PRIVATE(node); 460 struct ng_mppc_dir *const d = &priv->xmit; 461 u_char *inbuf, *outbuf; 462 int outlen, inlen; 463 u_int16_t header; 464 465 /* Initialize */ 466 *resultp = NULL; 467 header = d->cc; 468 if (d->flushed) { 469 header |= MPPC_FLAG_FLUSHED; 470 d->flushed = 0; 471 } 472 473 /* Work with contiguous regions of memory */ 474 inlen = m->m_pkthdr.len; 475 MALLOC(inbuf, u_char *, inlen, M_NETGRAPH_MPPC, M_NOWAIT); 476 if (inbuf == NULL) 477 return (ENOMEM); 478 m_copydata(m, 0, inlen, (caddr_t)inbuf); 479 if ((d->cfg.bits & MPPC_BIT) != 0) 480 outlen = MPPC_MAX_BLOWUP(inlen); 481 else 482 outlen = MPPC_HDRLEN + inlen; 483 MALLOC(outbuf, u_char *, outlen, M_NETGRAPH_MPPC, M_NOWAIT); 484 if (outbuf == NULL) { 485 FREE(inbuf, M_NETGRAPH_MPPC); 486 return (ENOMEM); 487 } 488 489 /* Compress "inbuf" into "outbuf" (if compression enabled) */ 490 #ifdef NETGRAPH_MPPC_COMPRESSION 491 if ((d->cfg.bits & MPPC_BIT) != 0) { 492 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS; 493 u_char *source, *dest; 494 u_long sourceCnt, destCnt; 495 int rtn; 496 497 /* Prepare to compress */ 498 source = inbuf; 499 sourceCnt = inlen; 500 dest = outbuf + MPPC_HDRLEN; 501 destCnt = outlen - MPPC_HDRLEN; 502 if ((d->cfg.bits & MPPE_STATELESS) == 0) 503 flags |= MPPC_SAVE_HISTORY; 504 505 /* Compress */ 506 rtn = MPPC_Compress(&source, &dest, &sourceCnt, 507 &destCnt, d->history, flags, 0); 508 509 /* Check return value */ 510 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 511 if ((rtn & MPPC_EXPANDED) == 0 512 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) { 513 outlen -= destCnt; 514 header |= MPPC_FLAG_COMPRESSED; 515 if ((rtn & MPPC_RESTART_HISTORY) != 0) 516 header |= MPPC_FLAG_RESTART; 517 } 518 d->flushed = (rtn & MPPC_EXPANDED) != 0 519 || (flags & MPPC_SAVE_HISTORY) == 0; 520 } 521 #endif 522 523 /* If we did not compress this packet, copy it to output buffer */ 524 if ((header & MPPC_FLAG_COMPRESSED) == 0) { 525 bcopy(inbuf, outbuf + MPPC_HDRLEN, inlen); 526 outlen = MPPC_HDRLEN + inlen; 527 } 528 FREE(inbuf, M_NETGRAPH_MPPC); 529 530 /* Always set the flushed bit in stateless mode */ 531 if ((d->cfg.bits & MPPE_STATELESS) != 0) 532 header |= MPPC_FLAG_FLUSHED; 533 534 /* Now encrypt packet (if encryption enabled) */ 535 #ifdef NETGRAPH_MPPC_ENCRYPTION 536 if ((d->cfg.bits & MPPE_BITS) != 0) { 537 538 /* Set header bits; need to reset key if we say we did */ 539 header |= MPPC_FLAG_ENCRYPTED; 540 if ((header & MPPC_FLAG_FLUSHED) != 0) 541 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 542 543 /* Update key if it's time */ 544 if ((d->cfg.bits & MPPE_STATELESS) != 0 545 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 546 ng_mppc_updatekey(d->cfg.bits, 547 d->cfg.startkey, d->key, &d->rc4); 548 } 549 550 /* Encrypt packet */ 551 rc4_crypt(&d->rc4, outbuf + MPPC_HDRLEN, 552 outbuf + MPPC_HDRLEN, outlen - MPPC_HDRLEN); 553 } 554 #endif 555 556 /* Update sequence number */ 557 d->cc++; 558 559 /* Install header */ 560 *((u_int16_t *)outbuf) = htons(header); 561 562 /* Return packet in an mbuf */ 563 *resultp = m_devget((caddr_t)outbuf, outlen, 0, NULL, NULL); 564 FREE(outbuf, M_NETGRAPH_MPPC); 565 return (*resultp == NULL ? ENOBUFS : 0); 566 } 567 568 /* 569 * Decompress/decrypt packet and put the result in a new mbuf at *resultp. 570 * The original mbuf is not free'd. 571 */ 572 static int 573 ng_mppc_decompress(node_p node, struct mbuf *m, struct mbuf **resultp) 574 { 575 const priv_p priv = NG_NODE_PRIVATE(node); 576 struct ng_mppc_dir *const d = &priv->recv; 577 u_int16_t header, cc; 578 u_int numLost; 579 u_char *buf; 580 int len; 581 582 /* Pull off header */ 583 if (m->m_pkthdr.len < MPPC_HDRLEN) 584 return (EINVAL); 585 m_copydata(m, 0, MPPC_HDRLEN, (caddr_t)&header); 586 header = ntohs(header); 587 cc = (header & MPPC_CCOUNT_MASK); 588 589 /* Copy payload into a contiguous region of memory */ 590 len = m->m_pkthdr.len - MPPC_HDRLEN; 591 MALLOC(buf, u_char *, len, M_NETGRAPH_MPPC, M_NOWAIT); 592 if (buf == NULL) 593 return (ENOMEM); 594 m_copydata(m, MPPC_HDRLEN, len, (caddr_t)buf); 595 596 /* Check for an unexpected jump in the sequence number */ 597 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 598 599 /* If flushed bit set, we can always handle packet */ 600 if ((header & MPPC_FLAG_FLUSHED) != 0) { 601 #ifdef NETGRAPH_MPPC_COMPRESSION 602 if (d->history != NULL) 603 MPPC_InitDecompressionHistory(d->history); 604 #endif 605 #ifdef NETGRAPH_MPPC_ENCRYPTION 606 if ((d->cfg.bits & MPPE_BITS) != 0) { 607 u_int rekey; 608 609 /* How many times are we going to have to re-key? */ 610 rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ? 611 numLost : (numLost / (MPPE_UPDATE_MASK + 1)); 612 if (rekey > MPPE_MAX_REKEY) { 613 log(LOG_ERR, "%s: too many (%d) packets" 614 " dropped, disabling node %p!", 615 __func__, numLost, node); 616 priv->recv.cfg.enable = 0; 617 goto failed; 618 } 619 620 /* Re-key as necessary to catch up to peer */ 621 while (d->cc != cc) { 622 if ((d->cfg.bits & MPPE_STATELESS) != 0 623 || (d->cc & MPPE_UPDATE_MASK) 624 == MPPE_UPDATE_FLAG) { 625 ng_mppc_updatekey(d->cfg.bits, 626 d->cfg.startkey, d->key, &d->rc4); 627 } 628 d->cc++; 629 } 630 631 /* Reset key (except in stateless mode, see below) */ 632 if ((d->cfg.bits & MPPE_STATELESS) == 0) 633 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 634 } 635 #endif 636 d->cc = cc; /* skip over lost seq numbers */ 637 numLost = 0; /* act like no packets were lost */ 638 } 639 640 /* Can't decode non-sequential packets without a flushed bit */ 641 if (numLost != 0) 642 goto failed; 643 644 /* Decrypt packet */ 645 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 646 647 /* Are we not expecting encryption? */ 648 if ((d->cfg.bits & MPPE_BITS) == 0) { 649 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 650 __func__, "encrypted"); 651 goto failed; 652 } 653 654 #ifdef NETGRAPH_MPPC_ENCRYPTION 655 /* Update key if it's time (always in stateless mode) */ 656 if ((d->cfg.bits & MPPE_STATELESS) != 0 657 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 658 ng_mppc_updatekey(d->cfg.bits, 659 d->cfg.startkey, d->key, &d->rc4); 660 } 661 662 /* Decrypt packet */ 663 rc4_crypt(&d->rc4, buf, buf, len); 664 #endif 665 } else { 666 667 /* Are we expecting encryption? */ 668 if ((d->cfg.bits & MPPE_BITS) != 0) { 669 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 670 __func__, "unencrypted"); 671 goto failed; 672 } 673 } 674 675 /* Update coherency count for next time (12 bit arithmetic) */ 676 d->cc++; 677 678 /* Check for unexpected compressed packet */ 679 if ((header & MPPC_FLAG_COMPRESSED) != 0 680 && (d->cfg.bits & MPPC_BIT) == 0) { 681 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 682 __func__, "compressed"); 683 failed: 684 FREE(buf, M_NETGRAPH_MPPC); 685 return (EINVAL); 686 } 687 688 #ifdef NETGRAPH_MPPC_COMPRESSION 689 /* Decompress packet */ 690 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 691 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 692 u_char *decompbuf, *source, *dest; 693 u_long sourceCnt, destCnt; 694 int decomplen, rtn; 695 696 /* Allocate a buffer for decompressed data */ 697 MALLOC(decompbuf, u_char *, MPPC_DECOMP_BUFSIZE 698 + MPPC_DECOMP_SAFETY, M_NETGRAPH_MPPC, M_NOWAIT); 699 if (decompbuf == NULL) { 700 FREE(buf, M_NETGRAPH_MPPC); 701 return (ENOMEM); 702 } 703 decomplen = MPPC_DECOMP_BUFSIZE; 704 705 /* Prepare to decompress */ 706 source = buf; 707 sourceCnt = len; 708 dest = decompbuf; 709 destCnt = decomplen; 710 if ((header & MPPC_FLAG_RESTART) != 0) 711 flags |= MPPC_RESTART_HISTORY; 712 713 /* Decompress */ 714 rtn = MPPC_Decompress(&source, &dest, 715 &sourceCnt, &destCnt, d->history, flags); 716 717 /* Check return value */ 718 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 719 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 720 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 721 log(LOG_ERR, "%s: decomp returned 0x%x", 722 __func__, rtn); 723 FREE(decompbuf, M_NETGRAPH_MPPC); 724 goto failed; 725 } 726 727 /* Replace compressed data with decompressed data */ 728 FREE(buf, M_NETGRAPH_MPPC); 729 buf = decompbuf; 730 len = decomplen - destCnt; 731 } 732 #endif 733 734 /* Return result in an mbuf */ 735 *resultp = m_devget((caddr_t)buf, len, 0, NULL, NULL); 736 FREE(buf, M_NETGRAPH_MPPC); 737 return (*resultp == NULL ? ENOBUFS : 0); 738 } 739 740 /* 741 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 742 */ 743 static void 744 ng_mppc_reset_req(node_p node) 745 { 746 const priv_p priv = NG_NODE_PRIVATE(node); 747 struct ng_mppc_dir *const d = &priv->xmit; 748 749 #ifdef NETGRAPH_MPPC_COMPRESSION 750 if (d->history != NULL) 751 MPPC_InitCompressionHistory(d->history); 752 #endif 753 #ifdef NETGRAPH_MPPC_ENCRYPTION 754 if ((d->cfg.bits & MPPE_STATELESS) == 0) 755 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 756 #endif 757 d->flushed = 1; 758 } 759 760 /* 761 * Generate a new encryption key 762 */ 763 static void 764 ng_mppc_getkey(const u_char *h, u_char *h2, int len) 765 { 766 static const u_char pad1[10] = 767 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 768 static const u_char pad2[10] = 769 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 770 u_char hash[20]; 771 SHA1_CTX c; 772 int k; 773 774 bzero(&hash, sizeof(hash)); 775 SHA1Init(&c); 776 SHA1Update(&c, h, len); 777 for (k = 0; k < 4; k++) 778 SHA1Update(&c, pad1, sizeof(pad2)); 779 SHA1Update(&c, h2, len); 780 for (k = 0; k < 4; k++) 781 SHA1Update(&c, pad2, sizeof(pad2)); 782 SHA1Final(hash, &c); 783 bcopy(hash, h2, len); 784 } 785 786 /* 787 * Update the encryption key 788 */ 789 static void 790 ng_mppc_updatekey(u_int32_t bits, 791 u_char *key0, u_char *key, struct rc4_state *rc4) 792 { 793 const int keylen = KEYLEN(bits); 794 795 ng_mppc_getkey(key0, key, keylen); 796 rc4_init(rc4, key, keylen); 797 rc4_crypt(rc4, key, key, keylen); 798 if ((bits & MPPE_40) != 0) 799 bcopy(&ng_mppe_weakenkey, key, 3); 800 else if ((bits & MPPE_56) != 0) 801 bcopy(&ng_mppe_weakenkey, key, 1); 802 rc4_init(rc4, key, keylen); 803 } 804 805