1/* 2 * ppp_mppe.c - interface MPPE to the PPP code. 3 * This version is for use with Linux kernel 2.6.14+ 4 * 5 * By Frank Cusack <fcusack@fcusack.com>. 6 * Copyright (c) 2002,2003,2004 Google, Inc. 7 * All rights reserved. 8 * 9 * License: 10 * Permission to use, copy, modify, and distribute this software and its 11 * documentation is hereby granted, provided that the above copyright 12 * notice appears in all copies. This software is provided without any 13 * warranty, express or implied. 14 * 15 * ALTERNATIVELY, provided that this notice is retained in full, this product 16 * may be distributed under the terms of the GNU General Public License (GPL), 17 * in which case the provisions of the GPL apply INSTEAD OF those given above. 18 * 19 * This program is free software; you can redistribute it and/or modify 20 * it under the terms of the GNU General Public License as published by 21 * the Free Software Foundation; either version 2 of the License, or 22 * (at your option) any later version. 23 * 24 * This program is distributed in the hope that it will be useful, 25 * but WITHOUT ANY WARRANTY; without even the implied warranty of 26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 27 * GNU General Public License for more details. 28 * 29 * You should have received a copy of the GNU General Public License 30 * along with this program; if not, write to the Free Software 31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 32 * 33 * 34 * Changelog: 35 * 08/12/05 - Matt Domsch <Matt_Domsch@dell.com> 36 * Only need extra skb padding on transmit, not receive. 37 * 06/18/04 - Matt Domsch <Matt_Domsch@dell.com>, Oleg Makarenko <mole@quadra.ru> 38 * Use Linux kernel 2.6 arc4 and sha1 routines rather than 39 * providing our own. 40 * 2/15/04 - TS: added #include <version.h> and testing for Kernel 41 * version before using 42 * MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are 43 * deprecated in 2.6 44 */ 45 46#include <linux/err.h> 47#include <linux/module.h> 48#include <linux/kernel.h> 49#include <linux/init.h> 50#include <linux/types.h> 51#include <linux/slab.h> 52#include <linux/string.h> 53#include <linux/crypto.h> 54#include <linux/mm.h> 55#include <linux/ppp_defs.h> 56#include <linux/ppp-comp.h> 57#include <linux/scatterlist.h> 58 59#include "ppp_mppe.h" 60 61MODULE_AUTHOR("Frank Cusack <fcusack@fcusack.com>"); 62MODULE_DESCRIPTION("Point-to-Point Protocol Microsoft Point-to-Point Encryption support"); 63MODULE_LICENSE("Dual BSD/GPL"); 64MODULE_ALIAS("ppp-compress-" __stringify(CI_MPPE)); 65MODULE_VERSION("1.0.2"); 66 67static unsigned int 68setup_sg(struct scatterlist *sg, const void *address, unsigned int length) 69{ 70 sg_set_buf(sg, address, length); 71 return length; 72} 73 74#define SHA1_PAD_SIZE 40 75 76/* 77 * kernel crypto API needs its arguments to be in kmalloc'd memory, not in the module 78 * static data area. That means sha_pad needs to be kmalloc'd. 79 */ 80 81struct sha_pad { 82 unsigned char sha_pad1[SHA1_PAD_SIZE]; 83 unsigned char sha_pad2[SHA1_PAD_SIZE]; 84}; 85static struct sha_pad *sha_pad; 86 87static inline void sha_pad_init(struct sha_pad *shapad) 88{ 89 memset(shapad->sha_pad1, 0x00, sizeof(shapad->sha_pad1)); 90 memset(shapad->sha_pad2, 0xF2, sizeof(shapad->sha_pad2)); 91} 92 93/* 94 * State for an MPPE (de)compressor. 95 */ 96struct ppp_mppe_state { 97 struct crypto_blkcipher *arc4; 98 struct crypto_hash *sha1; 99 unsigned char *sha1_digest; 100 unsigned char master_key[MPPE_MAX_KEY_LEN]; 101 unsigned char session_key[MPPE_MAX_KEY_LEN]; 102 unsigned keylen; /* key length in bytes */ 103 /* NB: 128-bit == 16, 40-bit == 8! */ 104 /* If we want to support 56-bit, */ 105 /* the unit has to change to bits */ 106 unsigned char bits; /* MPPE control bits */ 107 unsigned ccount; /* 12-bit coherency count (seqno) */ 108 unsigned stateful; /* stateful mode flag */ 109 int discard; /* stateful mode packet loss flag */ 110 int sanity_errors; /* take down LCP if too many */ 111 int unit; 112 int debug; 113 struct compstat stats; 114}; 115 116/* struct ppp_mppe_state.bits definitions */ 117#define MPPE_BIT_A 0x80 /* Encryption table were (re)inititalized */ 118#define MPPE_BIT_B 0x40 /* MPPC only (not implemented) */ 119#define MPPE_BIT_C 0x20 /* MPPC only (not implemented) */ 120#define MPPE_BIT_D 0x10 /* This is an encrypted frame */ 121 122#define MPPE_BIT_FLUSHED MPPE_BIT_A 123#define MPPE_BIT_ENCRYPTED MPPE_BIT_D 124 125#define MPPE_BITS(p) ((p)[4] & 0xf0) 126#define MPPE_CCOUNT(p) ((((p)[4] & 0x0f) << 8) + (p)[5]) 127#define MPPE_CCOUNT_SPACE 0x1000 /* The size of the ccount space */ 128 129#define MPPE_OVHD 2 /* MPPE overhead/packet */ 130#define SANITY_MAX 1600 /* Max bogon factor we will tolerate */ 131 132/* 133 * Key Derivation, from RFC 3078, RFC 3079. 134 * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079. 135 */ 136static void get_new_key_from_sha(struct ppp_mppe_state * state) 137{ 138 struct hash_desc desc; 139 struct scatterlist sg[4]; 140 unsigned int nbytes; 141 142 sg_init_table(sg, 4); 143 144 nbytes = setup_sg(&sg[0], state->master_key, state->keylen); 145 nbytes += setup_sg(&sg[1], sha_pad->sha_pad1, 146 sizeof(sha_pad->sha_pad1)); 147 nbytes += setup_sg(&sg[2], state->session_key, state->keylen); 148 nbytes += setup_sg(&sg[3], sha_pad->sha_pad2, 149 sizeof(sha_pad->sha_pad2)); 150 151 desc.tfm = state->sha1; 152 desc.flags = 0; 153 154 crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest); 155} 156 157/* 158 * Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3. 159 * Well, not what's written there, but rather what they meant. 160 */ 161static void mppe_rekey(struct ppp_mppe_state * state, int initial_key) 162{ 163 struct scatterlist sg_in[1], sg_out[1]; 164 struct blkcipher_desc desc = { .tfm = state->arc4 }; 165 166 get_new_key_from_sha(state); 167 if (!initial_key) { 168 crypto_blkcipher_setkey(state->arc4, state->sha1_digest, 169 state->keylen); 170 sg_init_table(sg_in, 1); 171 sg_init_table(sg_out, 1); 172 setup_sg(sg_in, state->sha1_digest, state->keylen); 173 setup_sg(sg_out, state->session_key, state->keylen); 174 if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in, 175 state->keylen) != 0) { 176 printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n"); 177 } 178 } else { 179 memcpy(state->session_key, state->sha1_digest, state->keylen); 180 } 181 if (state->keylen == 8) { 182 /* See RFC 3078 */ 183 state->session_key[0] = 0xd1; 184 state->session_key[1] = 0x26; 185 state->session_key[2] = 0x9e; 186 } 187 crypto_blkcipher_setkey(state->arc4, state->session_key, state->keylen); 188} 189 190/* 191 * Allocate space for a (de)compressor. 192 */ 193static void *mppe_alloc(unsigned char *options, int optlen) 194{ 195 struct ppp_mppe_state *state; 196 unsigned int digestsize; 197 198 if (optlen != CILEN_MPPE + sizeof(state->master_key) || 199 options[0] != CI_MPPE || options[1] != CILEN_MPPE) 200 goto out; 201 202 state = kzalloc(sizeof(*state), GFP_KERNEL); 203 if (state == NULL) 204 goto out; 205 206 207 state->arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC); 208 if (IS_ERR(state->arc4)) { 209 state->arc4 = NULL; 210 goto out_free; 211 } 212 213 state->sha1 = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC); 214 if (IS_ERR(state->sha1)) { 215 state->sha1 = NULL; 216 goto out_free; 217 } 218 219 digestsize = crypto_hash_digestsize(state->sha1); 220 if (digestsize < MPPE_MAX_KEY_LEN) 221 goto out_free; 222 223 state->sha1_digest = kmalloc(digestsize, GFP_KERNEL); 224 if (!state->sha1_digest) 225 goto out_free; 226 227 /* Save keys. */ 228 memcpy(state->master_key, &options[CILEN_MPPE], 229 sizeof(state->master_key)); 230 memcpy(state->session_key, state->master_key, 231 sizeof(state->master_key)); 232 233 /* 234 * We defer initial key generation until mppe_init(), as mppe_alloc() 235 * is called frequently during negotiation. 236 */ 237 238 return (void *)state; 239 240 out_free: 241 if (state->sha1_digest) 242 kfree(state->sha1_digest); 243 if (state->sha1) 244 crypto_free_hash(state->sha1); 245 if (state->arc4) 246 crypto_free_blkcipher(state->arc4); 247 kfree(state); 248 out: 249 return NULL; 250} 251 252/* 253 * Deallocate space for a (de)compressor. 254 */ 255static void mppe_free(void *arg) 256{ 257 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 258 if (state) { 259 if (state->sha1_digest) 260 kfree(state->sha1_digest); 261 if (state->sha1) 262 crypto_free_hash(state->sha1); 263 if (state->arc4) 264 crypto_free_blkcipher(state->arc4); 265 kfree(state); 266 } 267} 268 269/* 270 * Initialize (de)compressor state. 271 */ 272static int 273mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug, 274 const char *debugstr) 275{ 276 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 277 unsigned char mppe_opts; 278 279 if (optlen != CILEN_MPPE || 280 options[0] != CI_MPPE || options[1] != CILEN_MPPE) 281 return 0; 282 283 MPPE_CI_TO_OPTS(&options[2], mppe_opts); 284 if (mppe_opts & MPPE_OPT_128) 285 state->keylen = 16; 286 else if (mppe_opts & MPPE_OPT_40) 287 state->keylen = 8; 288 else { 289 printk(KERN_WARNING "%s[%d]: unknown key length\n", debugstr, 290 unit); 291 return 0; 292 } 293 if (mppe_opts & MPPE_OPT_STATEFUL) 294 state->stateful = 1; 295 296 /* Generate the initial session key. */ 297 mppe_rekey(state, 1); 298 299 if (debug) { 300 int i; 301 char mkey[sizeof(state->master_key) * 2 + 1]; 302 char skey[sizeof(state->session_key) * 2 + 1]; 303 304 printk(KERN_DEBUG "%s[%d]: initialized with %d-bit %s mode\n", 305 debugstr, unit, (state->keylen == 16) ? 128 : 40, 306 (state->stateful) ? "stateful" : "stateless"); 307 308 for (i = 0; i < sizeof(state->master_key); i++) 309 sprintf(mkey + i * 2, "%02x", state->master_key[i]); 310 for (i = 0; i < sizeof(state->session_key); i++) 311 sprintf(skey + i * 2, "%02x", state->session_key[i]); 312 printk(KERN_DEBUG 313 "%s[%d]: keys: master: %s initial session: %s\n", 314 debugstr, unit, mkey, skey); 315 } 316 317 /* 318 * Initialize the coherency count. The initial value is not specified 319 * in RFC 3078, but we can make a reasonable assumption that it will 320 * start at 0. Setting it to the max here makes the comp/decomp code 321 * do the right thing (determined through experiment). 322 */ 323 state->ccount = MPPE_CCOUNT_SPACE - 1; 324 325 /* 326 * Note that even though we have initialized the key table, we don't 327 * set the FLUSHED bit. This is contrary to RFC 3078, sec. 3.1. 328 */ 329 state->bits = MPPE_BIT_ENCRYPTED; 330 331 state->unit = unit; 332 state->debug = debug; 333 334 return 1; 335} 336 337static int 338mppe_comp_init(void *arg, unsigned char *options, int optlen, int unit, 339 int hdrlen, int debug) 340{ 341 /* ARGSUSED */ 342 return mppe_init(arg, options, optlen, unit, debug, "mppe_comp_init"); 343} 344 345/* 346 * We received a CCP Reset-Request (actually, we are sending a Reset-Ack), 347 * tell the compressor to rekey. Note that we MUST NOT rekey for 348 * every CCP Reset-Request; we only rekey on the next xmit packet. 349 * We might get multiple CCP Reset-Requests if our CCP Reset-Ack is lost. 350 * So, rekeying for every CCP Reset-Request is broken as the peer will not 351 * know how many times we've rekeyed. (If we rekey and THEN get another 352 * CCP Reset-Request, we must rekey again.) 353 */ 354static void mppe_comp_reset(void *arg) 355{ 356 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 357 358 state->bits |= MPPE_BIT_FLUSHED; 359} 360 361/* 362 * Compress (encrypt) a packet. 363 * It's strange to call this a compressor, since the output is always 364 * MPPE_OVHD + 2 bytes larger than the input. 365 */ 366static int 367mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf, 368 int isize, int osize) 369{ 370 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 371 struct blkcipher_desc desc = { .tfm = state->arc4 }; 372 int proto; 373 struct scatterlist sg_in[1], sg_out[1]; 374 375 /* 376 * Check that the protocol is in the range we handle. 377 */ 378 proto = PPP_PROTOCOL(ibuf); 379 if (proto < 0x0021 || proto > 0x00fa) 380 return 0; 381 382 /* Make sure we have enough room to generate an encrypted packet. */ 383 if (osize < isize + MPPE_OVHD + 2) { 384 /* Drop the packet if we should encrypt it, but can't. */ 385 printk(KERN_DEBUG "mppe_compress[%d]: osize too small! " 386 "(have: %d need: %d)\n", state->unit, 387 osize, osize + MPPE_OVHD + 2); 388 return -1; 389 } 390 391 osize = isize + MPPE_OVHD + 2; 392 393 /* 394 * Copy over the PPP header and set control bits. 395 */ 396 obuf[0] = PPP_ADDRESS(ibuf); 397 obuf[1] = PPP_CONTROL(ibuf); 398 obuf[2] = PPP_COMP >> 8; /* isize + MPPE_OVHD + 1 */ 399 obuf[3] = PPP_COMP; /* isize + MPPE_OVHD + 2 */ 400 obuf += PPP_HDRLEN; 401 402 state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE; 403 if (state->debug >= 7) 404 printk(KERN_DEBUG "mppe_compress[%d]: ccount %d\n", state->unit, 405 state->ccount); 406 obuf[0] = state->ccount >> 8; 407 obuf[1] = state->ccount & 0xff; 408 409 if (!state->stateful || /* stateless mode */ 410 ((state->ccount & 0xff) == 0xff) || /* "flag" packet */ 411 (state->bits & MPPE_BIT_FLUSHED)) { /* CCP Reset-Request */ 412 /* We must rekey */ 413 if (state->debug && state->stateful) 414 printk(KERN_DEBUG "mppe_compress[%d]: rekeying\n", 415 state->unit); 416 mppe_rekey(state, 0); 417 state->bits |= MPPE_BIT_FLUSHED; 418 } 419 obuf[0] |= state->bits; 420 state->bits &= ~MPPE_BIT_FLUSHED; /* reset for next xmit */ 421 422 obuf += MPPE_OVHD; 423 ibuf += 2; /* skip to proto field */ 424 isize -= 2; 425 426 /* Encrypt packet */ 427 sg_init_table(sg_in, 1); 428 sg_init_table(sg_out, 1); 429 setup_sg(sg_in, ibuf, isize); 430 setup_sg(sg_out, obuf, osize); 431 if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in, isize) != 0) { 432 printk(KERN_DEBUG "crypto_cypher_encrypt failed\n"); 433 return -1; 434 } 435 436 state->stats.unc_bytes += isize; 437 state->stats.unc_packets++; 438 state->stats.comp_bytes += osize; 439 state->stats.comp_packets++; 440 441 return osize; 442} 443 444/* 445 * Since every frame grows by MPPE_OVHD + 2 bytes, this is always going 446 * to look bad ... and the longer the link is up the worse it will get. 447 */ 448static void mppe_comp_stats(void *arg, struct compstat *stats) 449{ 450 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 451 452 *stats = state->stats; 453} 454 455static int 456mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit, 457 int hdrlen, int mru, int debug) 458{ 459 /* ARGSUSED */ 460 return mppe_init(arg, options, optlen, unit, debug, "mppe_decomp_init"); 461} 462 463/* 464 * We received a CCP Reset-Ack. Just ignore it. 465 */ 466static void mppe_decomp_reset(void *arg) 467{ 468 /* ARGSUSED */ 469 return; 470} 471 472/* 473 * Decompress (decrypt) an MPPE packet. 474 */ 475static int 476mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf, 477 int osize) 478{ 479 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 480 struct blkcipher_desc desc = { .tfm = state->arc4 }; 481 unsigned ccount; 482 int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED; 483 int sanity = 0; 484 struct scatterlist sg_in[1], sg_out[1]; 485 486 if (isize <= PPP_HDRLEN + MPPE_OVHD) { 487 if (state->debug) 488 printk(KERN_DEBUG 489 "mppe_decompress[%d]: short pkt (%d)\n", 490 state->unit, isize); 491 return DECOMP_ERROR; 492 } 493 494 /* 495 * Make sure we have enough room to decrypt the packet. 496 * Note that for our test we only subtract 1 byte whereas in 497 * mppe_compress() we added 2 bytes (+MPPE_OVHD); 498 * this is to account for possible PFC. 499 */ 500 if (osize < isize - MPPE_OVHD - 1) { 501 printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! " 502 "(have: %d need: %d)\n", state->unit, 503 osize, isize - MPPE_OVHD - 1); 504 return DECOMP_ERROR; 505 } 506 osize = isize - MPPE_OVHD - 2; /* assume no PFC */ 507 508 ccount = MPPE_CCOUNT(ibuf); 509 if (state->debug >= 7) 510 printk(KERN_DEBUG "mppe_decompress[%d]: ccount %d\n", 511 state->unit, ccount); 512 513 /* sanity checks -- terminate with extreme prejudice */ 514 if (!(MPPE_BITS(ibuf) & MPPE_BIT_ENCRYPTED)) { 515 printk(KERN_DEBUG 516 "mppe_decompress[%d]: ENCRYPTED bit not set!\n", 517 state->unit); 518 state->sanity_errors += 100; 519 sanity = 1; 520 } 521 if (!state->stateful && !flushed) { 522 printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set in " 523 "stateless mode!\n", state->unit); 524 state->sanity_errors += 100; 525 sanity = 1; 526 } 527 if (state->stateful && ((ccount & 0xff) == 0xff) && !flushed) { 528 printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set on " 529 "flag packet!\n", state->unit); 530 state->sanity_errors += 100; 531 sanity = 1; 532 } 533 534 if (sanity) { 535 if (state->sanity_errors < SANITY_MAX) 536 return DECOMP_ERROR; 537 else 538 /* 539 * Take LCP down if the peer is sending too many bogons. 540 * We don't want to do this for a single or just a few 541 * instances since it could just be due to packet corruption. 542 */ 543 return DECOMP_FATALERROR; 544 } 545 546 /* 547 * Check the coherency count. 548 */ 549 550 if (!state->stateful) { 551 /* RFC 3078, sec 8.1. Rekey for every packet. */ 552 while (state->ccount != ccount) { 553 mppe_rekey(state, 0); 554 state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE; 555 } 556 } else { 557 /* RFC 3078, sec 8.2. */ 558 if (!state->discard) { 559 /* normal state */ 560 state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE; 561 if (ccount != state->ccount) { 562 /* 563 * (ccount > state->ccount) 564 * Packet loss detected, enter the discard state. 565 * Signal the peer to rekey (by sending a CCP Reset-Request). 566 */ 567 state->discard = 1; 568 return DECOMP_ERROR; 569 } 570 } else { 571 /* discard state */ 572 if (!flushed) { 573 /* ccp.c will be silent (no additional CCP Reset-Requests). */ 574 return DECOMP_ERROR; 575 } else { 576 /* Rekey for every missed "flag" packet. */ 577 while ((ccount & ~0xff) != 578 (state->ccount & ~0xff)) { 579 mppe_rekey(state, 0); 580 state->ccount = 581 (state->ccount + 582 256) % MPPE_CCOUNT_SPACE; 583 } 584 585 /* reset */ 586 state->discard = 0; 587 state->ccount = ccount; 588 /* 589 * Another problem with RFC 3078 here. It implies that the 590 * peer need not send a Reset-Ack packet. But RFC 1962 591 * requires it. Hopefully, M$ does send a Reset-Ack; even 592 * though it isn't required for MPPE synchronization, it is 593 * required to reset CCP state. 594 */ 595 } 596 } 597 if (flushed) 598 mppe_rekey(state, 0); 599 } 600 601 /* 602 * Fill in the first part of the PPP header. The protocol field 603 * comes from the decrypted data. 604 */ 605 obuf[0] = PPP_ADDRESS(ibuf); /* +1 */ 606 obuf[1] = PPP_CONTROL(ibuf); /* +1 */ 607 obuf += 2; 608 ibuf += PPP_HDRLEN + MPPE_OVHD; 609 isize -= PPP_HDRLEN + MPPE_OVHD; /* -6 */ 610 /* net osize: isize-4 */ 611 612 /* 613 * Decrypt the first byte in order to check if it is 614 * a compressed or uncompressed protocol field. 615 */ 616 sg_init_table(sg_in, 1); 617 sg_init_table(sg_out, 1); 618 setup_sg(sg_in, ibuf, 1); 619 setup_sg(sg_out, obuf, 1); 620 if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, 1) != 0) { 621 printk(KERN_DEBUG "crypto_cypher_decrypt failed\n"); 622 return DECOMP_ERROR; 623 } 624 625 /* 626 * Do PFC decompression. 627 * This would be nicer if we were given the actual sk_buff 628 * instead of a char *. 629 */ 630 if ((obuf[0] & 0x01) != 0) { 631 obuf[1] = obuf[0]; 632 obuf[0] = 0; 633 obuf++; 634 osize++; 635 } 636 637 /* And finally, decrypt the rest of the packet. */ 638 setup_sg(sg_in, ibuf + 1, isize - 1); 639 setup_sg(sg_out, obuf + 1, osize - 1); 640 if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, isize - 1)) { 641 printk(KERN_DEBUG "crypto_cypher_decrypt failed\n"); 642 return DECOMP_ERROR; 643 } 644 645 state->stats.unc_bytes += osize; 646 state->stats.unc_packets++; 647 state->stats.comp_bytes += isize; 648 state->stats.comp_packets++; 649 650 /* good packet credit */ 651 state->sanity_errors >>= 1; 652 653 return osize; 654} 655 656/* 657 * Incompressible data has arrived (this should never happen!). 658 * We should probably drop the link if the protocol is in the range 659 * of what should be encrypted. At the least, we should drop this 660 * packet. (How to do this?) 661 */ 662static void mppe_incomp(void *arg, unsigned char *ibuf, int icnt) 663{ 664 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; 665 666 if (state->debug && 667 (PPP_PROTOCOL(ibuf) >= 0x0021 && PPP_PROTOCOL(ibuf) <= 0x00fa)) 668 printk(KERN_DEBUG 669 "mppe_incomp[%d]: incompressible (unencrypted) data! " 670 "(proto %04x)\n", state->unit, PPP_PROTOCOL(ibuf)); 671 672 state->stats.inc_bytes += icnt; 673 state->stats.inc_packets++; 674 state->stats.unc_bytes += icnt; 675 state->stats.unc_packets++; 676} 677 678/************************************************************* 679 * Module interface table 680 *************************************************************/ 681 682/* 683 * Procedures exported to if_ppp.c. 684 */ 685static struct compressor ppp_mppe = { 686 .compress_proto = CI_MPPE, 687 .comp_alloc = mppe_alloc, 688 .comp_free = mppe_free, 689 .comp_init = mppe_comp_init, 690 .comp_reset = mppe_comp_reset, 691 .compress = mppe_compress, 692 .comp_stat = mppe_comp_stats, 693 .decomp_alloc = mppe_alloc, 694 .decomp_free = mppe_free, 695 .decomp_init = mppe_decomp_init, 696 .decomp_reset = mppe_decomp_reset, 697 .decompress = mppe_decompress, 698 .incomp = mppe_incomp, 699 .decomp_stat = mppe_comp_stats, 700 .owner = THIS_MODULE, 701 .comp_extra = MPPE_PAD, 702}; 703 704/* 705 * ppp_mppe_init() 706 * 707 * Prior to allowing load, try to load the arc4 and sha1 crypto 708 * libraries. The actual use will be allocated later, but 709 * this way the module will fail to insmod if they aren't available. 710 */ 711 712static int __init ppp_mppe_init(void) 713{ 714 int answer; 715 if (!(crypto_has_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC) && 716 crypto_has_hash("sha1", 0, CRYPTO_ALG_ASYNC))) 717 return -ENODEV; 718 719 sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL); 720 if (!sha_pad) 721 return -ENOMEM; 722 sha_pad_init(sha_pad); 723 724 answer = ppp_register_compressor(&ppp_mppe); 725 726 if (answer == 0) 727 printk(KERN_INFO "PPP MPPE Compression module registered\n"); 728 else 729 kfree(sha_pad); 730 731 return answer; 732} 733 734static void __exit ppp_mppe_cleanup(void) 735{ 736 ppp_unregister_compressor(&ppp_mppe); 737 kfree(sha_pad); 738} 739 740module_init(ppp_mppe_init); 741module_exit(ppp_mppe_cleanup); 742