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 NETGRAPH_MPPC_COMPRESSION 69 /* XXX this file doesn't exist yet, but hopefully someday it will... */ 70 #include <net/mppc.h> 71 #endif 72 #ifdef NETGRAPH_MPPC_ENCRYPTION 73 #include <crypto/rc4/rc4.h> 74 #endif 75 #include <crypto/sha1.h> 76 77 /* Decompression blowup */ 78 #define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */ 79 #define MPPC_DECOMP_SAFETY 100 /* plus this much margin */ 80 81 /* MPPC/MPPE header length */ 82 #define MPPC_HDRLEN 2 83 84 /* Key length */ 85 #define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8) 86 87 /* What sequence number jump is too far */ 88 #define MPPC_INSANE_JUMP 256 89 90 /* MPPC packet header bits */ 91 #define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */ 92 #define MPPC_FLAG_RESTART 0x4000 /* compress history restart */ 93 #define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */ 94 #define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */ 95 #define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */ 96 97 #define MPPE_UPDATE_MASK 0xff /* coherency count when we're */ 98 #define MPPE_UPDATE_FLAG 0xff /* supposed to update key */ 99 100 #define MPPC_COMP_OK 0x05 101 #define MPPC_DECOMP_OK 0x05 102 103 /* Per direction info */ 104 struct ng_mppc_dir { 105 struct ng_mppc_config cfg; /* configuration */ 106 hook_p hook; /* netgraph hook */ 107 u_int16_t cc:12; /* coherency count */ 108 u_char flushed; /* clean history (xmit only) */ 109 #ifdef NETGRAPH_MPPC_COMPRESSION 110 u_char *history; /* compression history */ 111 #endif 112 #ifdef NETGRAPH_MPPC_ENCRYPTION 113 u_char key[MPPE_KEY_LEN]; /* session key */ 114 struct rc4_state rc4; /* rc4 state */ 115 #endif 116 }; 117 118 /* Node private data */ 119 struct ng_mppc_private { 120 struct ng_mppc_dir xmit; /* compress/encrypt config */ 121 struct ng_mppc_dir recv; /* decompress/decrypt config */ 122 char *ctrlpath; /* path to controlling node */ 123 }; 124 typedef struct ng_mppc_private *priv_p; 125 126 /* Netgraph node methods */ 127 static ng_constructor_t ng_mppc_constructor; 128 static ng_rcvmsg_t ng_mppc_rcvmsg; 129 static ng_shutdown_t ng_mppc_rmnode; 130 static ng_newhook_t ng_mppc_newhook; 131 static ng_rcvdata_t ng_mppc_rcvdata; 132 static ng_disconnect_t ng_mppc_disconnect; 133 134 /* Helper functions */ 135 static int ng_mppc_compress(node_p node, 136 struct mbuf *m, struct mbuf **resultp); 137 static int ng_mppc_decompress(node_p node, 138 struct mbuf *m, struct mbuf **resultp); 139 static void ng_mppc_getkey(const u_char *h, u_char *h2, int len); 140 static void ng_mppc_updatekey(u_int32_t bits, 141 u_char *key0, u_char *key, struct rc4_state *rc4); 142 static void ng_mppc_reset_req(node_p node); 143 144 /* Node type descriptor */ 145 static struct ng_type ng_mppc_typestruct = { 146 NG_VERSION, 147 NG_MPPC_NODE_TYPE, 148 NULL, 149 ng_mppc_constructor, 150 ng_mppc_rcvmsg, 151 ng_mppc_rmnode, 152 ng_mppc_newhook, 153 NULL, 154 NULL, 155 ng_mppc_rcvdata, 156 ng_mppc_rcvdata, 157 ng_mppc_disconnect, 158 NULL 159 }; 160 NETGRAPH_INIT(mppc, &ng_mppc_typestruct); 161 162 /* Fixed bit pattern to weaken keysize down to 40 bits */ 163 static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e }; 164 165 #define ERROUT(x) do { error = (x); goto done; } while (0) 166 167 /************************************************************************ 168 NETGRAPH NODE STUFF 169 ************************************************************************/ 170 171 /* 172 * Node type constructor 173 */ 174 static int 175 ng_mppc_constructor(node_p *nodep) 176 { 177 priv_p priv; 178 int error; 179 180 /* Allocate private structure */ 181 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO); 182 if (priv == NULL) 183 return (ENOMEM); 184 185 /* Call generic node constructor */ 186 if ((error = ng_make_node_common(&ng_mppc_typestruct, nodep))) { 187 FREE(priv, M_NETGRAPH); 188 return (error); 189 } 190 (*nodep)->private = priv; 191 192 /* Done */ 193 return (0); 194 } 195 196 /* 197 * Give our OK for a hook to be added 198 */ 199 static int 200 ng_mppc_newhook(node_p node, hook_p hook, const char *name) 201 { 202 const priv_p priv = node->private; 203 hook_p *hookPtr; 204 205 /* Check hook name */ 206 if (strcmp(name, NG_MPPC_HOOK_COMP) == 0) 207 hookPtr = &priv->xmit.hook; 208 else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0) 209 hookPtr = &priv->recv.hook; 210 else 211 return (EINVAL); 212 213 /* See if already connected */ 214 if (*hookPtr != NULL) 215 return (EISCONN); 216 217 /* OK */ 218 *hookPtr = hook; 219 return (0); 220 } 221 222 /* 223 * Receive a control message 224 */ 225 static int 226 ng_mppc_rcvmsg(node_p node, struct ng_mesg *msg, 227 const char *raddr, struct ng_mesg **rptr, hook_p lasthook) 228 { 229 const priv_p priv = node->private; 230 struct ng_mesg *resp = NULL; 231 int error = 0; 232 233 switch (msg->header.typecookie) { 234 case NGM_MPPC_COOKIE: 235 switch (msg->header.cmd) { 236 case NGM_MPPC_CONFIG_COMP: 237 case NGM_MPPC_CONFIG_DECOMP: 238 { 239 struct ng_mppc_config *const cfg 240 = (struct ng_mppc_config *)msg->data; 241 const int isComp = 242 msg->header.cmd == NGM_MPPC_CONFIG_COMP; 243 struct ng_mppc_dir *const d = isComp ? 244 &priv->xmit : &priv->recv; 245 246 /* Check configuration */ 247 if (msg->header.arglen != sizeof(*cfg)) 248 ERROUT(EINVAL); 249 if (cfg->enable) { 250 if ((cfg->bits & ~MPPC_VALID_BITS) != 0) 251 ERROUT(EINVAL); 252 #ifndef NETGRAPH_MPPC_COMPRESSION 253 if ((cfg->bits & MPPC_BIT) != 0) 254 ERROUT(EPROTONOSUPPORT); 255 #endif 256 #ifndef NETGRAPH_MPPC_ENCRYPTION 257 if ((cfg->bits & MPPE_BITS) != 0) 258 ERROUT(EPROTONOSUPPORT); 259 #endif 260 } else 261 cfg->bits = 0; 262 263 /* Save return address so we can send reset-req's */ 264 if (priv->ctrlpath != NULL) { 265 FREE(priv->ctrlpath, M_NETGRAPH); 266 priv->ctrlpath = NULL; 267 } 268 if (!isComp && raddr != NULL) { 269 MALLOC(priv->ctrlpath, char *, 270 strlen(raddr) + 1, M_NETGRAPH, M_NOWAIT); 271 if (priv->ctrlpath == NULL) 272 ERROUT(ENOMEM); 273 strcpy(priv->ctrlpath, raddr); 274 } 275 276 /* Configuration is OK, reset to it */ 277 d->cfg = *cfg; 278 279 #ifdef NETGRAPH_MPPC_COMPRESSION 280 /* Initialize state buffers for compression */ 281 if (d->history != NULL) { 282 FREE(d->history, M_NETGRAPH); 283 d->history = NULL; 284 } 285 if ((cfg->bits & MPPC_BIT) != 0) { 286 MALLOC(d->history, u_char *, 287 isComp ? MPPC_SizeOfCompressionHistory() : 288 MPPC_SizeOfDecompressionHistory(), 289 M_NETGRAPH, M_NOWAIT); 290 if (d->history == NULL) 291 ERROUT(ENOMEM); 292 if (isComp) 293 MPPC_InitCompressionHistory(d->history); 294 else { 295 MPPC_InitDecompressionHistory( 296 d->history); 297 } 298 } 299 #endif 300 301 #ifdef NETGRAPH_MPPC_ENCRYPTION 302 /* Generate initial session keys for encryption */ 303 if ((cfg->bits & MPPE_BITS) != 0) { 304 const int keylen = KEYLEN(cfg->bits); 305 306 bcopy(cfg->startkey, d->key, keylen); 307 ng_mppc_getkey(cfg->startkey, d->key, keylen); 308 if ((cfg->bits & MPPE_128) == 0) { 309 bcopy(&ng_mppe_weakenkey, d->key, 310 sizeof(ng_mppe_weakenkey)); 311 } 312 rc4_init(&d->rc4, d->key, keylen); 313 } 314 #endif 315 316 /* Initialize other state */ 317 d->cc = 0; 318 d->flushed = 0; 319 break; 320 } 321 322 case NGM_MPPC_RESETREQ: 323 ng_mppc_reset_req(node); 324 break; 325 326 default: 327 error = EINVAL; 328 break; 329 } 330 break; 331 default: 332 error = EINVAL; 333 break; 334 } 335 if (rptr) 336 *rptr = resp; 337 else if (resp) 338 FREE(resp, M_NETGRAPH); 339 340 done: 341 FREE(msg, M_NETGRAPH); 342 return (error); 343 } 344 345 /* 346 * Receive incoming data on our hook. 347 */ 348 static int 349 ng_mppc_rcvdata(hook_p hook, struct mbuf *m, meta_p meta, 350 struct mbuf **ret_m, meta_p *ret_meta) 351 { 352 const node_p node = hook->node; 353 const priv_p priv = node->private; 354 struct mbuf *out; 355 int error; 356 357 /* Compress and/or encrypt */ 358 if (hook == priv->xmit.hook) { 359 if (!priv->xmit.cfg.enable) { 360 NG_FREE_DATA(m, meta); 361 return (ENXIO); 362 } 363 if ((error = ng_mppc_compress(node, m, &out)) != 0) { 364 NG_FREE_DATA(m, meta); 365 return(error); 366 } 367 m_freem(m); 368 NG_SEND_DATA(error, priv->xmit.hook, out, meta); 369 return (error); 370 } 371 372 /* Decompress and/or decrypt */ 373 if (hook == priv->recv.hook) { 374 if (!priv->recv.cfg.enable) { 375 NG_FREE_DATA(m, meta); 376 return (ENXIO); 377 } 378 if ((error = ng_mppc_decompress(node, m, &out)) != 0) { 379 NG_FREE_DATA(m, meta); 380 if (error == EINVAL && priv->ctrlpath != NULL) { 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(node, msg, priv->ctrlpath, NULL); 389 } 390 return (error); 391 } 392 m_freem(m); 393 NG_SEND_DATA(error, priv->recv.hook, out, meta); 394 return (error); 395 } 396 397 /* Oops */ 398 panic("%s: unknown hook", __FUNCTION__); 399 } 400 401 /* 402 * Destroy node 403 */ 404 static int 405 ng_mppc_rmnode(node_p node) 406 { 407 const priv_p priv = node->private; 408 409 /* Take down netgraph node */ 410 node->flags |= NG_INVALID; 411 ng_cutlinks(node); 412 ng_unname(node); 413 if (priv->ctrlpath != NULL) 414 FREE(priv->ctrlpath, M_NETGRAPH); 415 #ifdef NETGRAPH_MPPC_COMPRESSION 416 if (priv->xmit.history != NULL) 417 FREE(priv->xmit.history, M_NETGRAPH); 418 if (priv->recv.history != NULL) 419 FREE(priv->recv.history, M_NETGRAPH); 420 #endif 421 bzero(priv, sizeof(*priv)); 422 FREE(priv, M_NETGRAPH); 423 node->private = NULL; 424 ng_unref(node); /* let the node escape */ 425 return (0); 426 } 427 428 /* 429 * Hook disconnection 430 */ 431 static int 432 ng_mppc_disconnect(hook_p hook) 433 { 434 const node_p node = hook->node; 435 const priv_p priv = node->private; 436 437 /* Zero out hook pointer */ 438 if (hook == priv->xmit.hook) 439 priv->xmit.hook = NULL; 440 if (hook == priv->recv.hook) 441 priv->recv.hook = NULL; 442 443 /* Go away if no longer connected */ 444 if (node->numhooks == 0) 445 ng_rmnode(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 = node->private; 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, 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, M_NOWAIT); 485 if (outbuf == NULL) { 486 FREE(inbuf, M_NETGRAPH); 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", __FUNCTION__)); 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); 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); 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 = node->private; 577 struct ng_mppc_dir *const d = &priv->recv; 578 u_int16_t header, cc, 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 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, M_NOWAIT); 592 if (buf == NULL) 593 return (ENOMEM); 594 m_copydata(m, MPPC_HDRLEN, len, (caddr_t)buf); 595 596 /* Check for insane jumps in sequence numbering (D.O.S. attack) */ 597 numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK); 598 if (numLost >= MPPC_INSANE_JUMP) { 599 log(LOG_ERR, "%s: insane jump %d", __FUNCTION__, numLost); 600 priv->recv.cfg.enable = 0; 601 goto failed; 602 } 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) { 612 613 /* Resync as necessary, skipping lost packets */ 614 while (d->cc != cc) { 615 if ((d->cfg.bits & MPPE_STATELESS) 616 || (d->cc & MPPE_UPDATE_MASK) 617 == MPPE_UPDATE_FLAG) { 618 ng_mppc_updatekey(d->cfg.bits, 619 d->cfg.startkey, d->key, &d->rc4); 620 } 621 d->cc++; 622 } 623 624 /* Reset key (except in stateless mode, see below) */ 625 if ((d->cfg.bits & MPPE_STATELESS) == 0) 626 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 627 } 628 #endif 629 d->cc = cc; /* skip over lost seq numbers */ 630 numLost = 0; /* act like no packets were lost */ 631 } 632 633 /* Can't decode non-sequential packets without a flushed bit */ 634 if (numLost != 0) 635 goto failed; 636 637 /* Decrypt packet */ 638 if ((header & MPPC_FLAG_ENCRYPTED) != 0) { 639 640 /* Are we not expecting encryption? */ 641 if ((d->cfg.bits & MPPE_BITS) == 0) { 642 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 643 __FUNCTION__, "encrypted"); 644 goto failed; 645 } 646 647 #ifdef NETGRAPH_MPPC_ENCRYPTION 648 /* Update key if it's time (always in stateless mode) */ 649 if ((d->cfg.bits & MPPE_STATELESS) != 0 650 || (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) { 651 ng_mppc_updatekey(d->cfg.bits, 652 d->cfg.startkey, d->key, &d->rc4); 653 } 654 655 /* Decrypt packet */ 656 rc4_crypt(&d->rc4, buf, buf, len); 657 #endif 658 } else { 659 660 /* Are we expecting encryption? */ 661 if ((d->cfg.bits & MPPE_BITS) != 0) { 662 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 663 __FUNCTION__, "unencrypted"); 664 goto failed; 665 } 666 } 667 668 /* Update coherency count for next time (12 bit arithmetic) */ 669 d->cc++; 670 671 /* Check for unexpected compressed packet */ 672 if ((header & MPPC_FLAG_COMPRESSED) != 0 673 && (d->cfg.bits & MPPC_BIT) == 0) { 674 log(LOG_ERR, "%s: rec'd unexpectedly %s packet", 675 __FUNCTION__, "compressed"); 676 failed: 677 FREE(buf, M_NETGRAPH); 678 return (EINVAL); 679 } 680 681 #ifdef NETGRAPH_MPPC_COMPRESSION 682 /* Decompress packet */ 683 if ((header & MPPC_FLAG_COMPRESSED) != 0) { 684 int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS; 685 u_char *decompbuf, *source, *dest; 686 u_long sourceCnt, destCnt; 687 int decomplen, rtn; 688 689 /* Allocate a buffer for decompressed data */ 690 MALLOC(decompbuf, u_char *, MPPC_DECOMP_BUFSIZE 691 + MPPC_DECOMP_SAFETY, M_NETGRAPH, M_NOWAIT); 692 if (decompbuf == NULL) { 693 FREE(buf, M_NETGRAPH); 694 return (ENOMEM); 695 } 696 decomplen = MPPC_DECOMP_BUFSIZE; 697 698 /* Prepare to decompress */ 699 source = buf; 700 sourceCnt = len; 701 dest = decompbuf; 702 destCnt = decomplen; 703 if ((header & MPPC_FLAG_RESTART) != 0) 704 flags |= MPPC_RESTART_HISTORY; 705 706 /* Decompress */ 707 rtn = MPPC_Decompress(&source, &dest, 708 &sourceCnt, &destCnt, d->history, flags); 709 710 /* Check return value */ 711 KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __FUNCTION__)); 712 if ((rtn & MPPC_DEST_EXHAUSTED) != 0 713 || (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) { 714 log(LOG_ERR, "%s: decomp returned 0x%x", 715 __FUNCTION__, rtn); 716 FREE(decompbuf, M_NETGRAPH); 717 goto failed; 718 } 719 720 /* Replace compressed data with decompressed data */ 721 FREE(buf, M_NETGRAPH); 722 buf = decompbuf; 723 len = decomplen - destCnt; 724 } 725 #endif 726 727 /* Return result in an mbuf */ 728 *resultp = m_devget((caddr_t)buf, len, 0, NULL, NULL); 729 FREE(buf, M_NETGRAPH); 730 return (*resultp == NULL ? ENOBUFS : 0); 731 } 732 733 /* 734 * The peer has sent us a CCP ResetRequest, so reset our transmit state. 735 */ 736 static void 737 ng_mppc_reset_req(node_p node) 738 { 739 const priv_p priv = node->private; 740 struct ng_mppc_dir *const d = &priv->xmit; 741 742 #ifdef NETGRAPH_MPPC_COMPRESSION 743 if (d->history != NULL) 744 MPPC_InitCompressionHistory(d->history); 745 #endif 746 #ifdef NETGRAPH_MPPC_ENCRYPTION 747 if ((d->cfg.bits & MPPE_STATELESS) == 0) 748 rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits)); 749 #endif 750 d->flushed = 1; 751 } 752 753 /* 754 * Generate a new encryption key 755 */ 756 static void 757 ng_mppc_getkey(const u_char *h, u_char *h2, int len) 758 { 759 static const u_char pad1[10] = 760 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; 761 static const u_char pad2[10] = 762 { 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, }; 763 u_char hash[20]; 764 SHA1_CTX c; 765 int k; 766 767 bzero(&hash, sizeof(hash)); 768 SHA1Init(&c); 769 SHA1Update(&c, h, len); 770 for (k = 0; k < 4; k++) 771 SHA1Update(&c, pad1, sizeof(pad2)); 772 SHA1Update(&c, h2, len); 773 for (k = 0; k < 4; k++) 774 SHA1Update(&c, pad2, sizeof(pad2)); 775 SHA1Final(hash, &c); 776 bcopy(hash, h2, len); 777 } 778 779 /* 780 * Update the encryption key 781 */ 782 static void 783 ng_mppc_updatekey(u_int32_t bits, 784 u_char *key0, u_char *key, struct rc4_state *rc4) 785 { 786 const int keylen = KEYLEN(bits); 787 788 ng_mppc_getkey(key0, key, keylen); 789 rc4_init(rc4, key, keylen); 790 rc4_crypt(rc4, key, key, keylen); 791 if ((bits & MPPE_128) == 0) 792 bcopy(&ng_mppe_weakenkey, key, sizeof(ng_mppe_weakenkey)); 793 rc4_init(rc4, key, keylen); 794 } 795 796