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sys/netgraph/ng_mppc.c
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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: releng/5.4/sys/netgraph/ng_mppc.c 141090 2005-01-31 23:27:04Z imp $ 42 */ 43 44 /* 45 * Microsoft PPP compression (MPPC) and encryption (MPPE) netgraph node type. 46 * 47 * You must define one or both of the NETGRAPH_MPPC_COMPRESSION and/or 48 * NETGRAPH_MPPC_ENCRYPTION options for this node type to be useful. 49 */ 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/kernel.h> 54 #include <sys/mbuf.h> 55 #include <sys/malloc.h> 56 #include <sys/errno.h> 57 #include <sys/syslog.h> 58 59 #include <netgraph/ng_message.h> 60 #include <netgraph/netgraph.h> 61 #include <netgraph/ng_mppc.h> 62 63 #include "opt_netgraph.h" 64 65 #if !defined(NETGRAPH_MPPC_COMPRESSION) && !defined(NETGRAPH_MPPC_ENCRYPTION) 66 #error Need either NETGRAPH_MPPC_COMPRESSION or NETGRAPH_MPPC_ENCRYPTION 67 #endif 68 69 #ifdef NG_SEPARATE_MALLOC 70 MALLOC_DEFINE(M_NETGRAPH_MPPC, "netgraph_mppc", "netgraph mppc node "); 71 #else 72 #define M_NETGRAPH_MPPC M_NETGRAPH 73 #endif 74 75 #ifdef NETGRAPH_MPPC_COMPRESSION 76 /* XXX this file doesn't exist yet, but hopefully someday it will... */ 77 #include <net/mppc.h> 78 #endif 79 #ifdef NETGRAPH_MPPC_ENCRYPTION 80 #include <crypto/rc4/rc4.h> 81 #endif 82 #include <crypto/sha1.h> 83 84 /* Decompression blowup */ 85 #define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */ 86 #define MPPC_DECOMP_SAFETY 100 /* plus this much margin */ 87 88 /* MPPC/MPPE header length */ 89 #define MPPC_HDRLEN 2 90 91 /* Key length */ 92 #define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8) 93 94 /* 95 * When packets are lost with MPPE, we may have to re-key arbitrarily 96 * many times to 'catch up' to the new jumped-ahead sequence number. 97 * Since this can be expensive, we pose a limit on how many re-keyings 98 * we will do at one time to avoid a possible D.O.S. vulnerability. 99 * This should instead be a configurable parameter. 100 */ 101 #define MPPE_MAX_REKEY 1000 102 103 /* MPPC packet header bits */ 104 #define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */ 105 #define MPPC_FLAG_RESTART 0x4000 /* compress history restart */ 106 #define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */ 107 #define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */ 108 #define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */ 109 110 #define MPPE_UPDATE_MASK 0xff /* coherency count when we're */ 111 #define MPPE_UPDATE_FLAG 0xff /* supposed to update key */ 112 113 #define MPPC_COMP_OK 0x05 114 #define MPPC_DECOMP_OK 0x05 115 116 /* Per direction info */ 117 struct ng_mppc_dir { 118 struct ng_mppc_config cfg; /* configuration */ 119 hook_p hook; /* netgraph hook */ 120 u_int16_t cc:12; /* coherency count */ 121 u_char flushed; /* clean history (xmit only) */ 122 #ifdef NETGRAPH_MPPC_COMPRESSION 123 u_char *history; /* compression history */ 124 #endif 125 #ifdef NETGRAPH_MPPC_ENCRYPTION 126 u_char key[MPPE_KEY_LEN]; /* session key */ 127 struct rc4_state rc4; /* rc4 state */ 128 #endif 129 }; 130 131 /* Node private data */ 132 struct ng_mppc_private { 133 struct ng_mppc_dir xmit; /* compress/encrypt config */ 134 struct ng_mppc_dir recv; /* decompress/decrypt config */ 135 ng_ID_t ctrlnode; /* path to controlling node */ 136 }; 137 typedef struct ng_mppc_private *priv_p; 138 139 /* Netgraph node methods */ 140 static ng_constructor_t ng_mppc_constructor; 141 static ng_rcvmsg_t ng_mppc_rcvmsg; 142 static ng_shutdown_t ng_mppc_shutdown; 143 static ng_newhook_t ng_mppc_newhook; 144 static ng_rcvdata_t ng_mppc_rcvdata; 145 static ng_disconnect_t ng_mppc_disconnect; 146 147 /* Helper functions */ 148 static int ng_mppc_compress(node_p node, 149 struct mbuf *m, struct mbuf **resultp); 150 static int ng_mppc_decompress(node_p node, 151 struct mbuf *m, struct mbuf **resultp); 152 static void ng_mppc_getkey(const u_char *h, u_char *h2, int len); 153 static void ng_mppc_updatekey(u_int32_t bits, 154 u_char *key0, u_char *key, struct rc4_state *rc4); 155 static void ng_mppc_reset_req(node_p node); 156 157 /* Node type descriptor */ 158 static struct ng_type ng_mppc_typestruct = { 159 .version = NG_ABI_VERSION, 160 .name = NG_MPPC_NODE_TYPE, 161 .constructor = ng_mppc_constructor, 162 .rcvmsg = ng_mppc_rcvmsg, 163 .shutdown = ng_mppc_shutdown, 164 .newhook = ng_mppc_newhook, 165 .rcvdata = ng_mppc_rcvdata, 166 .disconnect = ng_mppc_disconnect, 167 }; 168 NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 169 170 #ifdef NETGRAPH_MPPC_ENCRYPTION 171 /* Depend on separate rc4 module */ 172 MODULE_DEPEND(ng_mppc, rc4, 1, 1, 1); 173 #endif 174 175 /* Fixed bit pattern to weaken keysize down to 40 or 56 bits */ 176 static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e }; 177 178 #define ERROUT(x) do { error = (x); goto done; } while (0) 179 180 /************************************************************************ 181 NETGRAPH NODE STUFF 182 ************************************************************************/ 183 184 /* 185 * Node type constructor 186 */ 187 static int 188 ng_mppc_constructor(node_p node) 189 { 190 priv_p priv; 191 192 /* Allocate private structure */ 193 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_MPPC, M_NOWAIT | M_ZERO); 194 if (priv == NULL) 195 return (ENOMEM); 196 197 NG_NODE_SET_PRIVATE(node, 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 = NG_NODE_PRIVATE(node); 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, item_p item, hook_p lasthook) 234 { 235 const priv_p priv = NG_NODE_PRIVATE(node); 236 struct ng_mesg *resp = NULL; 237 int error = 0; 238 struct ng_mesg *msg; 239 240 NGI_GET_MSG(item, msg); 241 switch (msg->header.typecookie) { 242 case NGM_MPPC_COOKIE: 243 switch (msg->header.cmd) { 244 case NGM_MPPC_CONFIG_COMP: 245 case NGM_MPPC_CONFIG_DECOMP: 246 { 247 struct ng_mppc_config *const cfg 248 = (struct ng_mppc_config *)msg->data; 249 const int isComp = 250 msg->header.cmd == NGM_MPPC_CONFIG_COMP; 251 struct ng_mppc_dir *const d = isComp ? 252 &priv->xmit : &priv->recv; 253 254 /* Check configuration */ 255 if (msg->header.arglen != sizeof(*cfg)) 256 ERROUT(EINVAL); 257 if (cfg->enable) { 258 if ((cfg->bits & ~MPPC_VALID_BITS) != 0) 259 ERROUT(EINVAL); 260 #ifndef NETGRAPH_MPPC_COMPRESSION 261 if ((cfg->bits & MPPC_BIT) != 0) 262 ERROUT(EPROTONOSUPPORT); 263 #endif 264 #ifndef NETGRAPH_MPPC_ENCRYPTION 265 if ((cfg->bits & MPPE_BITS) != 0) 266 ERROUT(EPROTONOSUPPORT); 267 #endif 268 } else 269 cfg->bits = 0; 270 271 /* Save return address so we can send reset-req's */ 272 if (!isComp) 273 priv->ctrlnode = NGI_RETADDR(item); 274 275 /* Configuration is OK, reset to it */ 276 d->cfg = *cfg; 277 278 #ifdef NETGRAPH_MPPC_COMPRESSION 279 /* Initialize state buffers for compression */ 280 if (d->history != NULL) { 281 FREE(d->history, M_NETGRAPH_MPPC); 282 d->history = NULL; 283 } 284 if ((cfg->bits & MPPC_BIT) != 0) { 285 MALLOC(d->history, u_char *, 286 isComp ? MPPC_SizeOfCompressionHistory() : 287 MPPC_SizeOfDecompressionHistory(), 288 M_NETGRAPH_MPPC, M_NOWAIT); 289 if (d->history == NULL) 290 ERROUT(ENOMEM); 291 if (isComp) 292 MPPC_InitCompressionHistory(d->history); 293 else { 294 MPPC_InitDecompressionHistory( 295 d->history); 296 } 297 } 298 #endif 299 300 #ifdef NETGRAPH_MPPC_ENCRYPTION 301 /* Generate initial session keys for encryption */ 302 if ((cfg->bits & MPPE_BITS) != 0) { 303 const int keylen = KEYLEN(cfg->bits); 304 305 bcopy(cfg->startkey, d->key, keylen); 306 ng_mppc_getkey(cfg->startkey, d->key, keylen); 307 if ((cfg->bits & MPPE_40) != 0) 308 bcopy(&ng_mppe_weakenkey, d->key, 3); 309 else if ((cfg->bits & MPPE_56) != 0) 310 bcopy(&ng_mppe_weakenkey, d->key, 1); 311 rc4_init(&d->rc4, d->key, keylen); 312 } 313 #endif 314 315 /* Initialize other state */ 316 d->cc = 0; 317 d->flushed = 0; 318 break; 319 } 320 321 case NGM_MPPC_RESETREQ: 322 ng_mppc_reset_req(node); 323 break; 324 325 default: 326 error = EINVAL; 327 break; 328 } 329 break; 330 default: 331 error = EINVAL; 332 break; 333 } 334 done: 335 NG_RESPOND_MSG(error, node, item, resp); 336 NG_FREE_MSG(msg); 337 return (error); 338 } 339 340 /* 341 * Receive incoming data on our hook. 342 */ 343 static int 344 ng_mppc_rcvdata(hook_p hook, item_p item) 345 { 346 const node_p node = NG_HOOK_NODE(hook); 347 const priv_p priv = NG_NODE_PRIVATE(node); 348 struct mbuf *out; 349 int error; 350 struct mbuf *m; 351 352 NGI_GET_M(item, m); 353 /* Compress and/or encrypt */ 354 if (hook == priv->xmit.hook) { 355 if (!priv->xmit.cfg.enable) { 356 NG_FREE_M(m); 357 NG_FREE_ITEM(item); 358 return (ENXIO); 359 } 360 if ((error = ng_mppc_compress(node, m, &out)) != 0) { 361 NG_FREE_M(m); 362 NG_FREE_ITEM(item); 363 return(error); 364 } 365 NG_FREE_M(m); 366 NG_FWD_NEW_DATA(error, item, priv->xmit.hook, out); 367 return (error); 368 } 369 370 /* Decompress and/or decrypt */ 371 if (hook == priv->recv.hook) { 372 if (!priv->recv.cfg.enable) { 373 NG_FREE_M(m); 374 NG_FREE_ITEM(item); 375 return (ENXIO); 376 } 377 if ((error = ng_mppc_decompress(node, m, &out)) != 0) { 378 NG_FREE_M(m); 379 NG_FREE_ITEM(item); 380 if (error == EINVAL && priv->ctrlnode != 0) { 381 struct ng_mesg *msg; 382 383 /* Need to send a reset-request */ 384 NG_MKMESSAGE(msg, NGM_MPPC_COOKIE, 385 NGM_MPPC_RESETREQ, 0, M_NOWAIT); 386 if (msg == NULL) 387 return (error); 388 NG_SEND_MSG_ID(error, node, msg, 389 priv->ctrlnode, 0); 390 } 391 return (error); 392 } 393 NG_FREE_M(m); 394 NG_FWD_NEW_DATA(error, item, priv->recv.hook, out); 395 return (error); 396 } 397 398 /* Oops */ 399 panic("%s: unknown hook", __func__); 400 #ifdef RESTARTABLE_PANICS 401 return (EINVAL); 402 #endif 403 } 404 405 /* 406 * Destroy node 407 */ 408 static int 409 ng_mppc_shutdown(node_p node) 410 { 411 const priv_p priv = NG_NODE_PRIVATE(node); 412 413 /* Take down netgraph node */ 414 #ifdef NETGRAPH_MPPC_COMPRESSION 415 if (priv->xmit.history != NULL) 416 FREE(priv->xmit.history, M_NETGRAPH_MPPC); 417 if (priv->recv.history != NULL) 418 FREE(priv->recv.history, M_NETGRAPH_MPPC); 419 #endif 420 bzero(priv, sizeof(*priv)); 421 FREE(priv, M_NETGRAPH_MPPC); 422 NG_NODE_SET_PRIVATE(node, NULL); 423 NG_NODE_UNREF(node); /* let the node escape */ 424 return (0); 425 } 426 427 /* 428 * Hook disconnection 429 */ 430 static int 431 ng_mppc_disconnect(hook_p hook) 432 { 433 const node_p node = NG_HOOK_NODE(hook); 434 const priv_p priv = NG_NODE_PRIVATE(node); 435 436 /* Zero out hook pointer */ 437 if (hook == priv->xmit.hook) 438 priv->xmit.hook = NULL; 439 if (hook == priv->recv.hook) 440 priv->recv.hook = NULL; 441 442 /* Go away if no longer connected */ 443 if ((NG_NODE_NUMHOOKS(node) == 0) 444 && NG_NODE_IS_VALID(node)) 445 ng_rmnode_self(node); 446 return (0); 447 } 448 449 /************************************************************************ 450 HELPER STUFF 451 ************************************************************************/ 452 453 /* 454 * Compress/encrypt a packet and put the result in a new mbuf at *resultp. 455 * The original mbuf is not free'd. 456 */ 457 static int 458 ng_mppc_compress(node_p node, struct mbuf *m, struct mbuf **resultp) 459 { 460 const priv_p priv = NG_NODE_PRIVATE(node); 461 struct ng_mppc_dir *const d = &priv->xmit; 462 u_char *inbuf, *outbuf; 463 int outlen, inlen; 464 u_int16_t header; 465 466 /* Initialize */ 467 *resultp = NULL; 468 header = d->cc; 469 if (d->flushed) { 470 header |= MPPC_FLAG_FLUSHED; 471 d->flushed = 0; 472 } 473 474 /* Work with contiguous regions of memory */ 475 inlen = m->m_pkthdr.len; 476 MALLOC(inbuf, u_char *, inlen, M_NETGRAPH_MPPC, M_NOWAIT); 477 if (inbuf == NULL) 478 return (ENOMEM); 479 m_copydata(m, 0, inlen, (caddr_t)inbuf); 480 if ((d->cfg.bits & MPPC_BIT) != 0) 481 outlen = MPPC_MAX_BLOWUP(inlen); 482 else 483 outlen = MPPC_HDRLEN + inlen; 484 MALLOC(outbuf, u_char *, outlen, M_NETGRAPH_MPPC, M_NOWAIT); 485 if (outbuf == NULL) { 486 FREE(inbuf, M_NETGRAPH_MPPC); 487 return (ENOMEM); 488 } 489 490 /* Compress "inbuf" into "outbuf" (if compression enabled) */ 491 #ifdef NETGRAPH_MPPC_COMPRESSION 492 if ((d->cfg.bits & MPPC_BIT) != 0) { 493 u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS; 494 u_char *source, *dest; 495 u_long sourceCnt, destCnt; 496 int rtn; 497 498 /* Prepare to compress */ 499 source = inbuf; 500 sourceCnt = inlen; 501 dest = outbuf + MPPC_HDRLEN; 502 destCnt = outlen - MPPC_HDRLEN; 503 if ((d->cfg.bits & MPPE_STATELESS) == 0) 504 flags |= MPPC_SAVE_HISTORY; 505 506 /* Compress */ 507 rtn = MPPC_Compress(&source, &dest, &sourceCnt, 508 &destCnt, d->history, flags, 0); 509 510 /* Check return value */ 511 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 512 if ((rtn & MPPC_EXPANDED) == 0 513 && (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) { 514 outlen -= destCnt; 515 header |= MPPC_FLAG_COMPRESSED; 516 if ((rtn & MPPC_RESTART_HISTORY) != 0) 517 header |= MPPC_FLAG_RESTART; 518 } 519 d->flushed = (rtn & MPPC_EXPANDED) != 0 520 || (flags & MPPC_SAVE_HISTORY) == 0; 521 } 522 #endif 523 524 /* If we did not compress this packet, copy it to output buffer */ 525 if ((header & MPPC_FLAG_COMPRESSED) == 0) { 526 bcopy(inbuf, outbuf + MPPC_HDRLEN, inlen); 527 outlen = MPPC_HDRLEN + inlen; 528 } 529 FREE(inbuf, M_NETGRAPH_MPPC); 530 531 /* Always set the flushed bit in stateless mode */ 532 if ((d->cfg.bits & MPPE_STATELESS) != 0) 533 header |= MPPC_FLAG_FLUSHED; 534 535 /* Now encrypt packet (if encryption enabled) */ 536 #ifdef NETGRAPH_MPPC_ENCRYPTION 537 if ((d->cfg.bits & MPPE_BITS) != 0) { 538 539 /* Set header bits; need to reset key if we say we did */ 540 header |= MPPC_FLAG_ENCRYPTED; 541 if ((header & MPPC_FLAG_FLUSHED) != 0) 542 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 543 544 /* Update key if it's time */ 545 if ((d->cfg.bits & MPPE_STATELESS) != 0 546 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 547 ng_mppc_updatekey(d->cfg.bits, 548 d->cfg.startkey, d->key, &d->rc4); 549 } 550 551 /* Encrypt packet */ 552 rc4_crypt(&d->rc4, outbuf + MPPC_HDRLEN, 553 outbuf + MPPC_HDRLEN, outlen - MPPC_HDRLEN); 554 } 555 #endif 556 557 /* Update sequence number */ 558 d->cc++; 559 560 /* Install header */ 561 *((u_int16_t *)outbuf) = htons(header); 562 563 /* Return packet in an mbuf */ 564 *resultp = m_devget((caddr_t)outbuf, outlen, 0, NULL, NULL); 565 FREE(outbuf, M_NETGRAPH_MPPC); 566 return (*resultp == NULL ? ENOBUFS : 0); 567 } 568 569 /* 570 * Decompress/decrypt packet and put the result in a new mbuf at *resultp. 571 * The original mbuf is not free'd. 572 */ 573 static int 574 ng_mppc_decompress(node_p node, struct mbuf *m, struct mbuf **resultp) 575 { 576 const priv_p priv = NG_NODE_PRIVATE(node); 577 struct ng_mppc_dir *const d = &priv->recv; 578 u_int16_t header, cc; 579 u_int numLost; 580 u_char *buf; 581 int len; 582 583 /* Pull off header */ 584 if (m->m_pkthdr.len < MPPC_HDRLEN) 585 return (EINVAL); 586 m_copydata(m, 0, MPPC_HDRLEN, (caddr_t)&header); 587 header = ntohs(header); 588 cc = (header & MPPC_CCOUNT_MASK); 589 590 /* Copy payload into a contiguous region of memory */ 591 len = m->m_pkthdr.len - MPPC_HDRLEN; 592 MALLOC(buf, u_char *, len, M_NETGRAPH_MPPC, M_NOWAIT); 593 if (buf == NULL) 594 return (ENOMEM); 595 m_copydata(m, MPPC_HDRLEN, len, (caddr_t)buf); 596 597 /* Check for an unexpected jump in the sequence number */ 598 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 599 600 /* If flushed bit set, we can always handle packet */ 601 if ((header & MPPC_FLAG_FLUSHED) != 0) { 602 #ifdef NETGRAPH_MPPC_COMPRESSION 603 if (d->history != NULL) 604 MPPC_InitDecompressionHistory(d->history); 605 #endif 606 #ifdef NETGRAPH_MPPC_ENCRYPTION 607 if ((d->cfg.bits & MPPE_BITS) != 0) { 608 u_int rekey; 609 610 /* How many times are we going to have to re-key? */ 611 rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ? 612 numLost : (numLost / (MPPE_UPDATE_MASK + 1)); 613 if (rekey > MPPE_MAX_REKEY) { 614 log(LOG_ERR, "%s: too many (%d) packets" 615 " dropped, disabling node %p!", 616 __func__, numLost, node); 617 priv->recv.cfg.enable = 0; 618 goto failed; 619 } 620 621 /* Re-key as necessary to catch up to peer */ 622 while (d->cc != cc) { 623 if ((d->cfg.bits & MPPE_STATELESS) != 0 624 || (d->cc & MPPE_UPDATE_MASK) 625 == MPPE_UPDATE_FLAG) { 626 ng_mppc_updatekey(d->cfg.bits, 627 d->cfg.startkey, d->key, &d->rc4); 628 } 629 d->cc++; 630 } 631 632 /* Reset key (except in stateless mode, see below) */ 633 if ((d->cfg.bits & MPPE_STATELESS) == 0) 634 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 635 } 636 #endif 637 d->cc = cc; /* skip over lost seq numbers */ 638 numLost = 0; /* act like no packets were lost */ 639 } 640 641 /* Can't decode non-sequential packets without a flushed bit */ 642 if (numLost != 0) 643 goto failed; 644 645 /* Decrypt packet */ 646 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 647 648 /* Are we not expecting encryption? */ 649 if ((d->cfg.bits & MPPE_BITS) == 0) { 650 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 651 __func__, "encrypted"); 652 goto failed; 653 } 654 655 #ifdef NETGRAPH_MPPC_ENCRYPTION 656 /* Update key if it's time (always in stateless mode) */ 657 if ((d->cfg.bits & MPPE_STATELESS) != 0 658 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 659 ng_mppc_updatekey(d->cfg.bits, 660 d->cfg.startkey, d->key, &d->rc4); 661 } 662 663 /* Decrypt packet */ 664 rc4_crypt(&d->rc4, buf, buf, len); 665 #endif 666 } else { 667 668 /* Are we expecting encryption? */ 669 if ((d->cfg.bits & MPPE_BITS) != 0) { 670 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 671 __func__, "unencrypted"); 672 goto failed; 673 } 674 } 675 676 /* Update coherency count for next time (12 bit arithmetic) */ 677 d->cc++; 678 679 /* Check for unexpected compressed packet */ 680 if ((header & MPPC_FLAG_COMPRESSED) != 0 681 && (d->cfg.bits & MPPC_BIT) == 0) { 682 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 683 __func__, "compressed"); 684 failed: 685 FREE(buf, M_NETGRAPH_MPPC); 686 return (EINVAL); 687 } 688 689 #ifdef NETGRAPH_MPPC_COMPRESSION 690 /* Decompress packet */ 691 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 692 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 693 u_char *decompbuf, *source, *dest; 694 u_long sourceCnt, destCnt; 695 int decomplen, rtn; 696 697 /* Allocate a buffer for decompressed data */ 698 MALLOC(decompbuf, u_char *, MPPC_DECOMP_BUFSIZE 699 + MPPC_DECOMP_SAFETY, M_NETGRAPH_MPPC, M_NOWAIT); 700 if (decompbuf == NULL) { 701 FREE(buf, M_NETGRAPH_MPPC); 702 return (ENOMEM); 703 } 704 decomplen = MPPC_DECOMP_BUFSIZE; 705 706 /* Prepare to decompress */ 707 source = buf; 708 sourceCnt = len; 709 dest = decompbuf; 710 destCnt = decomplen; 711 if ((header & MPPC_FLAG_RESTART) != 0) 712 flags |= MPPC_RESTART_HISTORY; 713 714 /* Decompress */ 715 rtn = MPPC_Decompress(&source, &dest, 716 &sourceCnt, &destCnt, d->history, flags); 717 718 /* Check return value */ 719 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__)); 720 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 721 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 722 log(LOG_ERR, "%s: decomp returned 0x%x", 723 __func__, rtn); 724 FREE(decompbuf, M_NETGRAPH_MPPC); 725 goto failed; 726 } 727 728 /* Replace compressed data with decompressed data */ 729 FREE(buf, M_NETGRAPH_MPPC); 730 buf = decompbuf; 731 len = decomplen - destCnt; 732 } 733 #endif 734 735 /* Return result in an mbuf */ 736 *resultp = m_devget((caddr_t)buf, len, 0, NULL, NULL); 737 FREE(buf, M_NETGRAPH_MPPC); 738 return (*resultp == NULL ? ENOBUFS : 0); 739 } 740 741 /* 742 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 743 */ 744 static void 745 ng_mppc_reset_req(node_p node) 746 { 747 const priv_p priv = NG_NODE_PRIVATE(node); 748 struct ng_mppc_dir *const d = &priv->xmit; 749 750 #ifdef NETGRAPH_MPPC_COMPRESSION 751 if (d->history != NULL) 752 MPPC_InitCompressionHistory(d->history); 753 #endif 754 #ifdef NETGRAPH_MPPC_ENCRYPTION 755 if ((d->cfg.bits & MPPE_STATELESS) == 0) 756 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 757 #endif 758 d->flushed = 1; 759 } 760 761 /* 762 * Generate a new encryption key 763 */ 764 static void 765 ng_mppc_getkey(const u_char *h, u_char *h2, int len) 766 { 767 static const u_char pad1[10] = 768 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 769 static const u_char pad2[10] = 770 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 771 u_char hash[20]; 772 SHA1_CTX c; 773 int k; 774 775 bzero(&hash, sizeof(hash)); 776 SHA1Init(&c); 777 SHA1Update(&c, h, len); 778 for (k = 0; k < 4; k++) 779 SHA1Update(&c, pad1, sizeof(pad2)); 780 SHA1Update(&c, h2, len); 781 for (k = 0; k < 4; k++) 782 SHA1Update(&c, pad2, sizeof(pad2)); 783 SHA1Final(hash, &c); 784 bcopy(hash, h2, len); 785 } 786 787 /* 788 * Update the encryption key 789 */ 790 static void 791 ng_mppc_updatekey(u_int32_t bits, 792 u_char *key0, u_char *key, struct rc4_state *rc4) 793 { 794 const int keylen = KEYLEN(bits); 795 796 ng_mppc_getkey(key0, key, keylen); 797 rc4_init(rc4, key, keylen); 798 rc4_crypt(rc4, key, key, keylen); 799 if ((bits & MPPE_40) != 0) 800 bcopy(&ng_mppe_weakenkey, key, 3); 801 else if ((bits & MPPE_56) != 0) 802 bcopy(&ng_mppe_weakenkey, key, 1); 803 rc4_init(rc4, key, keylen); 804 } 805
Cache object: f7e2f7afc656578850ca141df35ab75b
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