MPPE/MPPC kernel module for Linux Microsoft Point-to-Point Encryption / Compression support http://www.polbox.com/h/hs001/linux-2.4.29-mppe-mppc-1.3.patch.gz --- a/Documentation/Configure.help +++ b/Documentation/Configure.help @@ -9974,6 +9974,28 @@ CONFIG_PPP_BSDCOMP module; it is called bsd_comp.o and will show up in the directory modules once you have said "make modules". If unsure, say N. +Microsoft PPP compression/encryption (MPPC/MPPE) +CONFIG_PPP_MPPE_MPPC + Support for the Microsoft Point-To-Point Compression (RFC2118) and + Microsoft Point-To-Point Encryption (RFC3078). These protocols are + supported by Microsoft Windows and wide range of "hardware" access + servers. MPPE is common protocol in Virtual Private Networks. According + to RFC3078, MPPE supports 40, 56 and 128-bit key lengths. Depending on + PPP daemon configuration on both ends of the link, following scenarios + are possible: + - only compression (MPPC) is used, + - only encryption (MPPE) is used, + - compression and encryption (MPPC+MPPE) are used. + + Please note that Hi/Fn (http://www.hifn.com) holds patent on MPPC so + you should check if this patent is valid in your country in order to + avoid legal problems. + + For more information please visit http://free.polbox.pl/h/hs001 + + To compile this driver as a module, choose M here. The module will + be called ppp_mppe_mppc.o. + PPP over Ethernet CONFIG_PPPOE Support for PPP over Ethernet. --- a/crypto/Config.in +++ b/crypto/Config.in @@ -11,7 +11,9 @@ if [ "$CONFIG_INET_AH" = "y" -o \ "$CONFIG_INET6_AH" = "y" -o \ "$CONFIG_INET6_AH" = "m" -o \ "$CONFIG_INET6_ESP" = "y" -o \ - "$CONFIG_INET6_ESP" = "m" ]; then + "$CONFIG_INET6_ESP" = "m" -o \ + "$CONFIG_PPP_MPPE_MPPC" = "y" -o \ + "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then define_bool CONFIG_CRYPTO y else bool 'Cryptographic API' CONFIG_CRYPTO @@ -51,11 +53,24 @@ if [ "$CONFIG_CRYPTO" = "y" ]; then "$CONFIG_INET6_AH" = "y" -o \ "$CONFIG_INET6_AH" = "m" -o \ "$CONFIG_INET6_ESP" = "y" -o \ - "$CONFIG_INET6_ESP" = "m" ]; then - define_bool CONFIG_CRYPTO_SHA1 y - else - tristate ' SHA1 digest algorithm' CONFIG_CRYPTO_SHA1 + "$CONFIG_INET6_ESP" = "m" -o \ + "$CONFIG_PPP_MPPE_MPPC" = "y" -o \ + "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then + if [ "$CONFIG_INET_AH" = "y" -o \ + "$CONFIG_INET_ESP" = "y" -o \ + "$CONFIG_INET6_AH" = "y" -o \ + "$CONFIG_INET6_ESP" = "y" -o \ + "$CONFIG_PPP_MPPE_MPPC" = "y" ]; then + define_tristate CONFIG_CRYPTO_SHA1 y + else + if [ "$CONFIG_CRYPTO_SHA1" != "y" -a \ + "$CONFIG_CRYPTO_SHA1" != "m" ]; then + define_tristate CONFIG_CRYPTO_SHA1 m + fi + fi fi + tristate ' SHA1 digest algorithm' CONFIG_CRYPTO_SHA1 + tristate ' SHA256 digest algorithm' CONFIG_CRYPTO_SHA256 tristate ' SHA384 and SHA512 digest algorithms' CONFIG_CRYPTO_SHA512 tristate ' Whirlpool digest algorithms' CONFIG_CRYPTO_WP512 @@ -76,7 +91,20 @@ if [ "$CONFIG_CRYPTO" = "y" ]; then tristate ' TEA and XTEA cipher algorithms' CONFIG_CRYPTO_TEA tristate ' Khazad cipher algorithm' CONFIG_CRYPTO_KHAZAD tristate ' Anubis cipher algorithm' CONFIG_CRYPTO_ANUBIS + + if [ "$CONFIG_PPP_MPPE_MPPC" = "y" -o \ + "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then + if [ "$CONFIG_PPP_MPPE_MPPC" = "y" ]; then + define_tristate CONFIG_CRYPTO_ARC4 y + else + if [ "$CONFIG_CRYPTO_ARC4" != "y" -a \ + "$CONFIG_CRYPTO_ARC4" != "m" ]; then + define_tristate CONFIG_CRYPTO_ARC4 m + fi + fi + fi tristate ' ARC4 cipher algorithm' CONFIG_CRYPTO_ARC4 + if [ "$CONFIG_INET_IPCOMP" = "y" -o \ "$CONFIG_INET_IPCOMP" = "m" -o \ "$CONFIG_INET6_IPCOMP" = "y" -o \ --- a/drivers/net/Config.in +++ b/drivers/net/Config.in @@ -336,6 +336,7 @@ if [ ! "$CONFIG_PPP" = "n" ]; then dep_tristate ' PPP support for sync tty ports' CONFIG_PPP_SYNC_TTY $CONFIG_PPP dep_tristate ' PPP Deflate compression' CONFIG_PPP_DEFLATE $CONFIG_PPP dep_tristate ' PPP BSD-Compress compression' CONFIG_PPP_BSDCOMP $CONFIG_PPP + dep_tristate ' Microsoft PPP compression/encryption (MPPC/MPPE)' CONFIG_PPP_MPPE_MPPC $CONFIG_PPP if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then dep_tristate ' PPP over Ethernet (EXPERIMENTAL)' CONFIG_PPPOE $CONFIG_PPP fi --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -166,6 +166,7 @@ obj-$(CONFIG_PPP_ASYNC) += ppp_async.o obj-$(CONFIG_PPP_SYNC_TTY) += ppp_synctty.o obj-$(CONFIG_PPP_DEFLATE) += ppp_deflate.o obj-$(CONFIG_PPP_BSDCOMP) += bsd_comp.o +obj-$(CONFIG_PPP_MPPE_MPPC) += ppp_mppe_mppc.o obj-$(CONFIG_PPPOE) += pppox.o pppoe.o obj-$(CONFIG_SLIP) += slip.o --- a/drivers/net/ppp_generic.c +++ b/drivers/net/ppp_generic.c @@ -19,7 +19,7 @@ * PPP driver, written by Michael Callahan and Al Longyear, and * subsequently hacked by Paul Mackerras. * - * ==FILEVERSION 20020217== + * ==FILEVERSION 20040509== */ #include @@ -102,6 +102,7 @@ struct ppp { spinlock_t rlock; /* lock for receive side 58 */ spinlock_t wlock; /* lock for transmit side 5c */ int mru; /* max receive unit 60 */ + int mru_alloc; /* MAX(1500,MRU) for dev_alloc_skb() */ unsigned int flags; /* control bits 64 */ unsigned int xstate; /* transmit state bits 68 */ unsigned int rstate; /* receive state bits 6c */ @@ -552,7 +553,9 @@ static int ppp_ioctl(struct inode *inode case PPPIOCSMRU: if (get_user(val, (int *) arg)) break; - ppp->mru = val; + ppp->mru_alloc = ppp->mru = val; + if (ppp->mru_alloc < PPP_MRU) + ppp->mru_alloc = PPP_MRU; /* increase for broken peers */ err = 0; break; @@ -1025,14 +1028,37 @@ ppp_send_frame(struct ppp *ppp, struct s case PPP_CCP: /* peek at outbound CCP frames */ ppp_ccp_peek(ppp, skb, 0); + /* + * When LZS or MPPE/MPPC has been negotiated we don't send + * CCP_RESETACK after receiving CCP_RESETREQ; in fact pppd + * sends such a packet but we silently discard it here + */ + if (CCP_CODE(skb->data+2) == CCP_RESETACK + && (ppp->xcomp->compress_proto == CI_MPPE + || ppp->xcomp->compress_proto == CI_LZS)) { + --ppp->stats.tx_packets; + ppp->stats.tx_bytes -= skb->len - 2; + kfree_skb(skb); + return; + } break; } /* try to do packet compression */ if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0 && proto != PPP_LCP && proto != PPP_CCP) { - new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len, - GFP_ATOMIC); + int comp_ovhd = 0; + /* + * because of possible data expansion when MPPC or LZS + * is used, allocate compressor's buffer 12.5% bigger + * than MTU + */ + if (ppp->xcomp->compress_proto == CI_MPPE) + comp_ovhd = ((ppp->dev->mtu * 9) / 8) + 1 + MPPE_OVHD; + else if (ppp->xcomp->compress_proto == CI_LZS) + comp_ovhd = ((ppp->dev->mtu * 9) / 8) + 1 + LZS_OVHD; + new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len + + comp_ovhd, GFP_ATOMIC); if (new_skb == 0) { printk(KERN_ERR "PPP: no memory (comp pkt)\n"); goto drop; @@ -1050,9 +1076,21 @@ ppp_send_frame(struct ppp *ppp, struct s skb = new_skb; skb_put(skb, len); skb_pull(skb, 2); /* pull off A/C bytes */ - } else { + } else if (len == 0) { /* didn't compress, or CCP not up yet */ kfree_skb(new_skb); + } else { + /* + * (len < 0) + * MPPE requires that we do not send unencrypted + * frames. The compressor will return -1 if we + * should drop the frame. We cannot simply test + * the compress_proto because MPPE and MPPC share + * the same number. + */ + printk(KERN_ERR "ppp: compressor dropped pkt\n"); + kfree_skb(new_skb); + goto drop; } } @@ -1540,14 +1578,15 @@ ppp_decompress_frame(struct ppp *ppp, st int len; if (proto == PPP_COMP) { - ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN); + ns = dev_alloc_skb(ppp->mru_alloc + PPP_HDRLEN); if (ns == 0) { printk(KERN_ERR "ppp_decompress_frame: no memory\n"); goto err; } /* the decompressor still expects the A/C bytes in the hdr */ len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2, - skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN); + skb->len + 2, ns->data, + ppp->mru_alloc + PPP_HDRLEN); if (len < 0) { /* Pass the compressed frame to pppd as an error indication. */ @@ -1573,7 +1612,14 @@ ppp_decompress_frame(struct ppp *ppp, st return skb; err: - ppp->rstate |= SC_DC_ERROR; + if (ppp->rcomp->compress_proto != CI_MPPE + && ppp->rcomp->compress_proto != CI_LZS) { + /* + * If decompression protocol isn't MPPE/MPPC or LZS, we set + * SC_DC_ERROR flag and wait for CCP_RESETACK + */ + ppp->rstate |= SC_DC_ERROR; + } ppp_receive_error(ppp); return skb; } @@ -2253,6 +2299,7 @@ ppp_create_interface(int unit, int *retp /* Initialize the new ppp unit */ ppp->file.index = unit; ppp->mru = PPP_MRU; + ppp->mru_alloc = PPP_MRU; init_ppp_file(&ppp->file, INTERFACE); ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */ for (i = 0; i < NUM_NP; ++i) --- /dev/null +++ b/drivers/net/ppp_mppe_mppc.c @@ -0,0 +1,1312 @@ +/* + * ppp_mppe_mppc.c - MPPC/MPPE "compressor/decompressor" module. + * + * Copyright (c) 1994 Árpád Magosányi + * Copyright (c) 1999 Tim Hockin, Cobalt Networks Inc. + * Copyright (c) 2002-2005 Jan Dubiec + * + * Permission to use, copy, modify, and distribute this software and its + * documentation is hereby granted, provided that the above copyright + * notice appears in all copies. This software is provided without any + * warranty, express or implied. + * + * The code is based on MPPE kernel module written by Árpád Magosányi and + * Tim Hockin which can be found on http://planetmirror.com/pub/mppe/. + * I have added MPPC and 56 bit session keys support in MPPE. + * + * WARNING! Although this is open source code, its usage in some countries + * (in particular in the USA) may violate Stac Inc. patent for MPPC. + * + * ==FILEVERSION 20050202== + * + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +/* + * In 2.4.x kernels macro offset_in_page() is not defined in linux/mm.h so + * we define it here; PAGE_MASK is defined in asm/page.h which is included + * by linux/mm.h. + */ +#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK) + +/* + * State for a mppc/mppe "(de)compressor". + */ +struct ppp_mppe_state { + struct crypto_tfm *arc4_tfm; + struct crypto_tfm *sha1_tfm; + u8 *sha1_digest; + u8 master_key[MPPE_MAX_KEY_LEN]; + u8 session_key[MPPE_MAX_KEY_LEN]; + u8 mppc; /* do we use compression (MPPC)? */ + u8 mppe; /* do we use encryption (MPPE)? */ + u8 keylen; /* key length in bytes */ + u8 bitkeylen; /* key length in bits */ + u16 ccount; /* coherency counter */ + u16 bits; /* MPPC/MPPE control bits */ + u8 stateless; /* do we use stateless mode? */ + u8 nextflushed; /* set A bit in the next outgoing packet; + used only by compressor*/ + u8 flushexpected; /* drop packets until A bit is received; + used only by decompressor*/ + u8 *hist; /* MPPC history */ + u16 *hash; /* Hash table; used only by compressor */ + u16 histptr; /* history "cursor" */ + int unit; + int debug; + int mru; + struct compstat stats; +}; + +#define MPPE_HIST_LEN 8192 /* MPPC history size */ +#define MPPE_MAX_CCOUNT 0x0FFF /* max. coherency counter value */ + +#define MPPE_BIT_FLUSHED 0x80 /* bit A */ +#define MPPE_BIT_RESET 0x40 /* bit B */ +#define MPPE_BIT_COMP 0x20 /* bit C */ +#define MPPE_BIT_ENCRYPTED 0x10 /* bit D */ + +#define MPPE_SALT0 0xD1 /* values used in MPPE key derivation */ +#define MPPE_SALT1 0x26 /* according to RFC3079 */ +#define MPPE_SALT2 0x9E + +#define MPPE_CCOUNT(x) ((((x)[4] & 0x0f) << 8) + (x)[5]) +#define MPPE_BITS(x) ((x)[4] & 0xf0) +#define MPPE_CTRLHI(x) ((((x)->ccount & 0xf00)>>8)|((x)->bits)) +#define MPPE_CTRLLO(x) ((x)->ccount & 0xff) + +/* + * Kernel Crypto API needs its arguments to be in kmalloc'd memory, not in the + * module static data area. That means sha_pad needs to be kmalloc'd. It is done + * in mppe_module_init(). This has been pointed out on 30th July 2004 by Oleg + * Makarenko on pptpclient-devel mailing list. + */ +#define SHA1_PAD_SIZE 40 +struct sha_pad { + unsigned char sha_pad1[SHA1_PAD_SIZE]; + unsigned char sha_pad2[SHA1_PAD_SIZE]; +}; +static struct sha_pad *sha_pad; + +static inline void +setup_sg(struct scatterlist *sg, const void *address, unsigned int length) +{ + sg[0].page = virt_to_page(address); + sg[0].offset = offset_in_page(address); + sg[0].length = length; +} + +static inline void +arc4_setkey(struct ppp_mppe_state *state, const unsigned char *key, + const unsigned int keylen) +{ + crypto_cipher_setkey(state->arc4_tfm, key, keylen); +} + +static inline void +arc4_encrypt(struct ppp_mppe_state *state, const unsigned char *in, + const unsigned int len, unsigned char *out) +{ + struct scatterlist sgin[4], sgout[4]; + + setup_sg(sgin, in, len); + setup_sg(sgout, out, len); + crypto_cipher_encrypt(state->arc4_tfm, sgout, sgin, len); +} + +#define arc4_decrypt arc4_encrypt + +/* + * Key Derivation, from RFC 3078, RFC 3079. + * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079. + */ +static void +get_new_key_from_sha(struct ppp_mppe_state *state, unsigned char *interim_key) +{ + struct scatterlist sg[4]; + + setup_sg(&sg[0], state->master_key, state->keylen); + setup_sg(&sg[1], sha_pad->sha_pad1, sizeof(sha_pad->sha_pad1)); + setup_sg(&sg[2], state->session_key, state->keylen); + setup_sg(&sg[3], sha_pad->sha_pad2, sizeof(sha_pad->sha_pad2)); + + crypto_digest_digest (state->sha1_tfm, sg, 4, state->sha1_digest); + + memcpy(interim_key, state->sha1_digest, state->keylen); +} + +static void +mppe_change_key(struct ppp_mppe_state *state, int initialize) +{ + unsigned char interim_key[MPPE_MAX_KEY_LEN]; + + get_new_key_from_sha(state, interim_key); + if (initialize) { + memcpy(state->session_key, interim_key, state->keylen); + } else { + arc4_setkey(state, interim_key, state->keylen); + arc4_encrypt(state, interim_key, state->keylen, state->session_key); + } + if (state->keylen == 8) { + if (state->bitkeylen == 40) { + state->session_key[0] = MPPE_SALT0; + state->session_key[1] = MPPE_SALT1; + state->session_key[2] = MPPE_SALT2; + } else { + state->session_key[0] = MPPE_SALT0; + } + } + arc4_setkey(state, state->session_key, state->keylen); +} + +/* increase 12-bit coherency counter */ +static inline void +mppe_increase_ccount(struct ppp_mppe_state *state) +{ + state->ccount = (state->ccount + 1) & MPPE_MAX_CCOUNT; + if (state->mppe) { + if (state->stateless) { + mppe_change_key(state, 0); + state->nextflushed = 1; + } else { + if ((state->ccount & 0xff) == 0xff) { + mppe_change_key(state, 0); + } + } + } +} + +/* allocate space for a MPPE/MPPC (de)compressor. */ +/* comp != 0 -> init compressor */ +/* comp = 0 -> init decompressor */ +static void * +mppe_alloc(unsigned char *options, int opt_len, int comp) +{ + struct ppp_mppe_state *state; + unsigned int digestsize; + u8* fname; + + fname = comp ? "mppe_comp_alloc" : "mppe_decomp_alloc"; + + /* + * Hack warning - additionally to the standard MPPC/MPPE configuration + * options, pppd passes to the (de)copressor 8 or 16 byte session key. + * Therefore options[1] contains MPPC/MPPE configuration option length + * (CILEN_MPPE = 6), but the real options length, depending on the key + * length, is 6+8 or 6+16. + */ + if (opt_len < CILEN_MPPE) { + printk(KERN_WARNING "%s: wrong options length: %u\n", fname, opt_len); + return NULL; + } + + if (options[0] != CI_MPPE || options[1] != CILEN_MPPE || + (options[2] & ~MPPE_STATELESS) != 0 || + options[3] != 0 || options[4] != 0 || + (options[5] & ~(MPPE_128BIT|MPPE_56BIT|MPPE_40BIT|MPPE_MPPC)) != 0 || + (options[5] & (MPPE_128BIT|MPPE_56BIT|MPPE_40BIT|MPPE_MPPC)) == 0) { + printk(KERN_WARNING "%s: options rejected: o[0]=%02x, o[1]=%02x, " + "o[2]=%02x, o[3]=%02x, o[4]=%02x, o[5]=%02x\n", fname, options[0], + options[1], options[2], options[3], options[4], options[5]); + return NULL; + } + + state = (struct ppp_mppe_state *)kmalloc(sizeof(*state), GFP_KERNEL); + if (state == NULL) { + printk(KERN_ERR "%s: cannot allocate space for %scompressor\n", fname, + comp ? "" : "de"); + return NULL; + } + memset(state, 0, sizeof(struct ppp_mppe_state)); + + state->mppc = options[5] & MPPE_MPPC; /* Do we use MPPC? */ + state->mppe = options[5] & (MPPE_128BIT | MPPE_56BIT | + MPPE_40BIT); /* Do we use MPPE? */ + + if (state->mppc) { + /* allocate MPPC history */ + state->hist = (u8*)vmalloc(2*MPPE_HIST_LEN*sizeof(u8)); + if (state->hist == NULL) { + kfree(state); + printk(KERN_ERR "%s: cannot allocate space for MPPC history\n", + fname); + return NULL; + } + + /* allocate hashtable for MPPC compressor */ + if (comp) { + state->hash = (u16*)vmalloc(MPPE_HIST_LEN*sizeof(u16)); + if (state->hash == NULL) { + vfree(state->hist); + kfree(state); + printk(KERN_ERR "%s: cannot allocate space for MPPC history\n", + fname); + return NULL; + } + } + } + + if (state->mppe) { /* specific for MPPE */ + /* Load ARC4 algorithm */ + state->arc4_tfm = crypto_alloc_tfm("arc4", 0); + if (state->arc4_tfm == NULL) { + if (state->mppc) { + vfree(state->hash); + if (comp) + vfree(state->hist); + } + kfree(state); + printk(KERN_ERR "%s: cannot load ARC4 module\n", fname); + return NULL; + } + + /* Load SHA1 algorithm */ + state->sha1_tfm = crypto_alloc_tfm("sha1", 0); + if (state->sha1_tfm == NULL) { + crypto_free_tfm(state->arc4_tfm); + if (state->mppc) { + vfree(state->hash); + if (comp) + vfree(state->hist); + } + kfree(state); + printk(KERN_ERR "%s: cannot load SHA1 module\n", fname); + return NULL; + } + + digestsize = crypto_tfm_alg_digestsize(state->sha1_tfm); + if (digestsize < MPPE_MAX_KEY_LEN) { + crypto_free_tfm(state->sha1_tfm); + crypto_free_tfm(state->arc4_tfm); + if (state->mppc) { + vfree(state->hash); + if (comp) + vfree(state->hist); + } + kfree(state); + printk(KERN_ERR "%s: CryptoAPI SHA1 digest size too small\n", fname); + } + + state->sha1_digest = kmalloc(digestsize, GFP_KERNEL); + if (!state->sha1_digest) { + crypto_free_tfm(state->sha1_tfm); + crypto_free_tfm(state->arc4_tfm); + if (state->mppc) { + vfree(state->hash); + if (comp) + vfree(state->hist); + } + kfree(state); + printk(KERN_ERR "%s: cannot allocate space for SHA1 digest\n", fname); + } + + memcpy(state->master_key, options+CILEN_MPPE, MPPE_MAX_KEY_LEN); + memcpy(state->session_key, state->master_key, MPPE_MAX_KEY_LEN); + /* initial key generation is done in mppe_init() */ + } + + MOD_INC_USE_COUNT; + + return (void *) state; +} + +static void * +mppe_comp_alloc(unsigned char *options, int opt_len) +{ + return mppe_alloc(options, opt_len, 1); +} + +static void * +mppe_decomp_alloc(unsigned char *options, int opt_len) +{ + return mppe_alloc(options, opt_len, 0); +} + +/* cleanup the (de)compressor */ +static void +mppe_comp_free(void *arg) +{ + struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; + + if (state != NULL) { + if (state->mppe) { + if (state->sha1_tfm != NULL) + crypto_free_tfm(state->sha1_tfm); + if (state->arc4_tfm != NULL) + crypto_free_tfm(state->arc4_tfm); + } + if (state->hist != NULL) + vfree(state->hist); + if (state->hash != NULL) + vfree(state->hash); + kfree(state); + } + + MOD_DEC_USE_COUNT; +} + +/* init MPPC/MPPE (de)compresor */ +/* comp != 0 -> init compressor */ +/* comp = 0 -> init decompressor */ +static int +mppe_init(void *arg, unsigned char *options, int opt_len, int unit, + int hdrlen, int mru, int debug, int comp) +{ + struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; + u8* fname; + + fname = comp ? "mppe_comp_init" : "mppe_decomp_init"; + + if (opt_len < CILEN_MPPE) { + if (debug) + printk(KERN_WARNING "%s: wrong options length: %u\n", + fname, opt_len); + return 0; + } + + if (options[0] != CI_MPPE || options[1] != CILEN_MPPE || + (options[2] & ~MPPE_STATELESS) != 0 || + options[3] != 0 || options[4] != 0 || + (options[5] & ~(MPPE_56BIT|MPPE_128BIT|MPPE_40BIT|MPPE_MPPC)) != 0 || + (options[5] & (MPPE_56BIT|MPPE_128BIT|MPPE_40BIT|MPPE_MPPC)) == 0) { + if (debug) + printk(KERN_WARNING "%s: options rejected: o[0]=%02x, o[1]=%02x, " + "o[2]=%02x, o[3]=%02x, o[4]=%02x, o[5]=%02x\n", fname, + options[0], options[1], options[2], options[3], options[4], + options[5]); + return 0; + } + + if ((options[5] & ~MPPE_MPPC) != MPPE_128BIT && + (options[5] & ~MPPE_MPPC) != MPPE_56BIT && + (options[5] & ~MPPE_MPPC) != MPPE_40BIT && + (options[5] & MPPE_MPPC) != MPPE_MPPC) { + if (debug) + printk(KERN_WARNING "%s: don't know what to do: o[5]=%02x\n", + fname, options[5]); + return 0; + } + + state->mppc = options[5] & MPPE_MPPC; /* Do we use MPPC? */ + state->mppe = options[5] & (MPPE_128BIT | MPPE_56BIT | + MPPE_40BIT); /* Do we use MPPE? */ + state->stateless = options[2] & MPPE_STATELESS; /* Do we use stateless mode? */ + + switch (state->mppe) { + case MPPE_40BIT: /* 40 bit key */ + state->keylen = 8; + state->bitkeylen = 40; + break; + case MPPE_56BIT: /* 56 bit key */ + state->keylen = 8; + state->bitkeylen = 56; + break; + case MPPE_128BIT: /* 128 bit key */ + state->keylen = 16; + state->bitkeylen = 128; + break; + default: + state->keylen = 0; + state->bitkeylen = 0; + } + + state->ccount = MPPE_MAX_CCOUNT; + state->bits = 0; + state->unit = unit; + state->debug = debug; + state->histptr = MPPE_HIST_LEN; + if (state->mppc) { /* reset history if MPPC was negotiated */ + memset(state->hist, 0, 2*MPPE_HIST_LEN*sizeof(u8)); + } + + if (state->mppe) { /* generate initial session keys */ + mppe_change_key(state, 1); + } + + if (comp) { /* specific for compressor */ + state->nextflushed = 1; + } else { /* specific for decompressor */ + state->mru = mru; + state->flushexpected = 1; + } + + return 1; +} + +static int +mppe_comp_init(void *arg, unsigned char *options, int opt_len, int unit, + int hdrlen, int debug) +{ + return mppe_init(arg, options, opt_len, unit, hdrlen, 0, debug, 1); +} + + +static int +mppe_decomp_init(void *arg, unsigned char *options, int opt_len, int unit, + int hdrlen, int mru, int debug) +{ + return mppe_init(arg, options, opt_len, unit, hdrlen, mru, debug, 0); +} + +static void +mppe_comp_reset(void *arg) +{ + struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg; + + if (state->debug) + printk(KERN_DEBUG "%s%d: resetting MPPC/MPPE compressor\n", + __FUNCTION__, state->unit); + + state->nextflushed = 1; + if (state->mppe) + arc4_setkey(state, state->session_key, state->keylen); +} + +static void +mppe_decomp_reset(void *arg) +{ + /* When MPPC/MPPE is in use, we shouldn't receive any CCP Reset-Ack. + But when we receive such a packet, we just ignore it. */ + return; +} + +static void +mppe_stats(void *arg, struct compstat *stats) +{ + struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg; + + *stats = state->stats; +} + +/***************************/ +/**** Compression stuff ****/ +/***************************/ +/* inserts 1 to 8 bits into the output buffer */ +static inline void putbits8(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l) +{ + buf += *i; + if (*l >= n) { + *l = (*l) - n; + val <<= *l; + *buf = *buf | (val & 0xff); + if (*l == 0) { + *l = 8; + (*i)++; + *(++buf) = 0; + } + } else { + (*i)++; + *l = 8 - n + (*l); + val <<= *l; + *buf = *buf | ((val >> 8) & 0xff); + *(++buf) = val & 0xff; + } +} + +/* inserts 9 to 16 bits into the output buffer */ +static inline void putbits16(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l) +{ + buf += *i; + if (*l >= n - 8) { + (*i)++; + *l = 8 - n + (*l); + val <<= *l; + *buf = *buf | ((val >> 8) & 0xff); + *(++buf) = val & 0xff; + if (*l == 0) { + *l = 8; + (*i)++; + *(++buf) = 0; + } + } else { + (*i)++; (*i)++; + *l = 16 - n + (*l); + val <<= *l; + *buf = *buf | ((val >> 16) & 0xff); + *(++buf) = (val >> 8) & 0xff; + *(++buf) = val & 0xff; + } +} + +/* inserts 17 to 24 bits into the output buffer */ +static inline void putbits24(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l) +{ + buf += *i; + if (*l >= n - 16) { + (*i)++; (*i)++; + *l = 16 - n + (*l); + val <<= *l; + *buf = *buf | ((val >> 16) & 0xff); + *(++buf) = (val >> 8) & 0xff; + *(++buf) = val & 0xff; + if (*l == 0) { + *l = 8; + (*i)++; + *(++buf) = 0; + } + } else { + (*i)++; (*i)++; (*i)++; + *l = 24 - n + (*l); + val <<= *l; + *buf = *buf | ((val >> 24) & 0xff); + *(++buf) = (val >> 16) & 0xff; + *(++buf) = (val >> 8) & 0xff; + *(++buf) = val & 0xff; + } +} + +static int +mppc_compress(struct ppp_mppe_state *state, unsigned char *ibuf, + unsigned char *obuf, int isize, int osize) +{ + u32 olen, off, len, idx, i, l; + u8 *hist, *sbuf, *p, *q, *r, *s; + + /* + At this point, to avoid possible buffer overflow caused by packet + expansion during/after compression, we should make sure that + osize >= (((isize*9)/8)+1)+2, but we don't do that because in + ppp_generic.c we simply allocate bigger obuf. + + Maximum MPPC packet expansion is 12.5%. This is the worst case when + all octets in the input buffer are >= 0x80 and we cannot find any + repeated tokens. Additionally we have to reserve 2 bytes for MPPE/MPPC + status bits and coherency counter. + */ + + hist = state->hist + MPPE_HIST_LEN; + /* check if there is enough room at the end of the history */ + if (state->histptr + isize >= 2*MPPE_HIST_LEN) { + state->bits |= MPPE_BIT_RESET; + state->histptr = MPPE_HIST_LEN; + memcpy(state->hist, hist, MPPE_HIST_LEN); + } + /* add packet to the history; isize must be <= MPPE_HIST_LEN */ + sbuf = state->hist + state->histptr; + memcpy(sbuf, ibuf, isize); + state->histptr += isize; + + /* compress data */ + r = sbuf + isize; + *obuf = olen = i = 0; + l = 8; + while (i < isize - 2) { + s = q = sbuf + i; + idx = ((40543*((((s[0]<<4)^s[1])<<4)^s[2]))>>4) & 0x1fff; + p = hist + state->hash[idx]; + state->hash[idx] = (u16) (s - hist); + off = s - p; + if (off > MPPE_HIST_LEN - 1 || off < 1 || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++) { + /* no match found; encode literal byte */ + if (ibuf[i] < 0x80) { /* literal byte < 0x80 */ + putbits8(obuf, (u32) ibuf[i], 8, &olen, &l); + } else { /* literal byte >= 0x80 */ + putbits16(obuf, (u32) (0x100|(ibuf[i]&0x7f)), 9, &olen, &l); + } + ++i; + continue; + } + if (r - q >= 64) { + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || + *p++ != *s++; + if (s - q == 64) { + p--; s--; + while((*p++ == *s++) && (s < r) && (p < q)); + } + } else { + while((*p++ == *s++) && (s < r) && (p < q)); + } + len = s - q - 1; + i += len; + + /* at least 3 character match found; code data */ + /* encode offset */ + if (off < 64) { /* 10-bit offset; 0 <= offset < 64 */ + putbits16(obuf, 0x3c0|off, 10, &olen, &l); + } else if (off < 320) { /* 12-bit offset; 64 <= offset < 320 */ + putbits16(obuf, 0xe00|(off-64), 12, &olen, &l); + } else if (off < 8192) { /* 16-bit offset; 320 <= offset < 8192 */ + putbits16(obuf, 0xc000|(off-320), 16, &olen, &l); + } else { + /* This shouldn't happen; we return 0 what means "packet expands", + and we send packet uncompressed. */ + if (state->debug) + printk(KERN_DEBUG "%s%d: wrong offset value: %d\n", + __FUNCTION__, state->unit, off); + return 0; + } + /* encode length of match */ + if (len < 4) { /* length = 3 */ + putbits8(obuf, 0, 1, &olen, &l); + } else if (len < 8) { /* 4 <= length < 8 */ + putbits8(obuf, 0x08|(len&0x03), 4, &olen, &l); + } else if (len < 16) { /* 8 <= length < 16 */ + putbits8(obuf, 0x30|(len&0x07), 6, &olen, &l); + } else if (len < 32) { /* 16 <= length < 32 */ + putbits8(obuf, 0xe0|(len&0x0f), 8, &olen, &l); + } else if (len < 64) { /* 32 <= length < 64 */ + putbits16(obuf, 0x3c0|(len&0x1f), 10, &olen, &l); + } else if (len < 128) { /* 64 <= length < 128 */ + putbits16(obuf, 0xf80|(len&0x3f), 12, &olen, &l); + } else if (len < 256) { /* 128 <= length < 256 */ + putbits16(obuf, 0x3f00|(len&0x7f), 14, &olen, &l); + } else if (len < 512) { /* 256 <= length < 512 */ + putbits16(obuf, 0xfe00|(len&0xff), 16, &olen, &l); + } else if (len < 1024) { /* 512 <= length < 1024 */ + putbits24(obuf, 0x3fc00|(len&0x1ff), 18, &olen, &l); + } else if (len < 2048) { /* 1024 <= length < 2048 */ + putbits24(obuf, 0xff800|(len&0x3ff), 20, &olen, &l); + } else if (len < 4096) { /* 2048 <= length < 4096 */ + putbits24(obuf, 0x3ff000|(len&0x7ff), 22, &olen, &l); + } else if (len < 8192) { /* 4096 <= length < 8192 */ + putbits24(obuf, 0xffe000|(len&0xfff), 24, &olen, &l); + } else { + /* This shouldn't happen; we return 0 what means "packet expands", + and send packet uncompressed. */ + if (state->debug) + printk(KERN_DEBUG "%s%d: wrong length of match value: %d\n", + __FUNCTION__, state->unit, len); + return 0; + } + } + + /* Add remaining octets to the output */ + while(isize - i > 0) { + if (ibuf[i] < 0x80) { /* literal byte < 0x80 */ + putbits8(obuf, (u32) ibuf[i++], 8, &olen, &l); + } else { /* literal byte >= 0x80 */ + putbits16(obuf, (u32) (0x100|(ibuf[i++]&0x7f)), 9, &olen, &l); + } + } + /* Reset unused bits of the last output octet */ + if ((l != 0) && (l != 8)) { + putbits8(obuf, 0, l, &olen, &l); + } + + return (int) olen; +} + +int +mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf, + int isize, int osize) +{ + struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; + int proto, olen, complen, off; + unsigned char *wptr; + + /* Check that the protocol is in the range we handle. */ + proto = PPP_PROTOCOL(ibuf); + if (proto < 0x0021 || proto > 0x00fa) + return 0; + + wptr = obuf; + /* Copy over the PPP header */ + wptr[0] = PPP_ADDRESS(ibuf); + wptr[1] = PPP_CONTROL(ibuf); + wptr[2] = PPP_COMP >> 8; + wptr[3] = PPP_COMP; + wptr += PPP_HDRLEN + (MPPE_OVHD / 2); /* Leave two octets for MPPE/MPPC bits */ + + /* + * In ver. 0.99 protocol field was compressed. Deflate and BSD compress + * do PFC before actual compression, RCF2118 and RFC3078 are not precise + * on this topic so I decided to do PFC. Unfortunately this change caused + * incompatibility with older/other MPPE/MPPC modules. I have received + * a lot of complaints from unexperienced users so I have decided to revert + * to previous state, i.e. the protocol field is sent uncompressed now. + * Although this may be changed in the future. + * + * Receiving side (mppe_decompress()) still accepts packets with compressed + * and uncompressed protocol field so you shouldn't get "Unsupported protocol + * 0x2145 received" messages anymore. + */ + //off = (proto > 0xff) ? 2 : 3; /* PFC - skip first protocol byte if 0 */ + off = 2; + + ibuf += off; + + mppe_increase_ccount(state); + + if (state->nextflushed) { + state->bits |= MPPE_BIT_FLUSHED; + state->nextflushed = 0; + if (state->mppe && !state->stateless) { + /* + * If this is the flag packet, the key has been already changed in + * mppe_increase_ccount() so we dont't do it once again. + */ + if ((state->ccount & 0xff) != 0xff) { + arc4_setkey(state, state->session_key, state->keylen); + } + } + if (state->mppc) { /* reset history */ + state->bits |= MPPE_BIT_RESET; + state->histptr = MPPE_HIST_LEN; + memset(state->hist + MPPE_HIST_LEN, 0, MPPE_HIST_LEN*sizeof(u8)); + } + } + + if (state->mppc && !state->mppe) { /* Do only compression */ + complen = mppc_compress(state, ibuf, wptr, isize - off, + osize - PPP_HDRLEN - (MPPE_OVHD / 2)); + /* + * TODO: Implement an heuristics to handle packet expansion in a smart + * way. Now, when a packet expands, we send it as uncompressed and + * when next packet is sent we have to reset compressor's history. + * Maybe it would be better to send such packet as compressed in order + * to keep history's continuity. + */ + if ((complen > isize) || (complen > osize - PPP_HDRLEN) || + (complen == 0)) { + /* packet expands */ + state->nextflushed = 1; + memcpy(wptr, ibuf, isize - off); + olen = isize - (off - 2) + MPPE_OVHD; + (state->stats).inc_bytes += olen; + (state->stats).inc_packets++; + } else { + state->bits |= MPPE_BIT_COMP; + olen = complen + PPP_HDRLEN + (MPPE_OVHD / 2); + (state->stats).comp_bytes += olen; + (state->stats).comp_packets++; + } + } else { /* Do encryption with or without compression */ + state->bits |= MPPE_BIT_ENCRYPTED; + if (!state->mppc && state->mppe) { /* Do only encryption */ + /* read from ibuf, write to wptr, adjust for PPP_HDRLEN */ + arc4_encrypt(state, ibuf, isize - off, wptr); + olen = isize - (off - 2) + MPPE_OVHD; + (state->stats).inc_bytes += olen; + (state->stats).inc_packets++; + } else { /* Do compression and then encryption - RFC3078 */ + complen = mppc_compress(state, ibuf, wptr, isize - off, + osize - PPP_HDRLEN - (MPPE_OVHD / 2)); + /* + * TODO: Implement an heuristics to handle packet expansion in a smart + * way. Now, when a packet expands, we send it as uncompressed and + * when next packet is sent we have to reset compressor's history. + * Maybe it would be good to send such packet as compressed in order + * to keep history's continuity. + */ + if ((complen > isize) || (complen > osize - PPP_HDRLEN) || + (complen == 0)) { + /* packet expands */ + state->nextflushed = 1; + arc4_encrypt(state, ibuf, isize - off, wptr); + olen = isize - (off - 2) + MPPE_OVHD; + (state->stats).inc_bytes += olen; + (state->stats).inc_packets++; + } else { + state->bits |= MPPE_BIT_COMP; + /* Hack warning !!! RC4 implementation which we use does + encryption "in place" - it means that input and output + buffers can be *the same* memory area. Therefore we don't + need to use a temporary buffer. But be careful - other + implementations don't have to be so nice. + I used to use ibuf as temporary buffer here, but it led + packet sniffers into error. Thanks to Wilfried Weissmann + for pointing that. */ + arc4_encrypt(state, wptr, complen, wptr); + olen = complen + PPP_HDRLEN + (MPPE_OVHD / 2); + (state->stats).comp_bytes += olen; + (state->stats).comp_packets++; + } + } + } + + /* write status bits and coherency counter into the output buffer */ + wptr = obuf + PPP_HDRLEN; + wptr[0] = MPPE_CTRLHI(state); + wptr[1] = MPPE_CTRLLO(state); + + state->bits = 0; + + (state->stats).unc_bytes += isize; + (state->stats).unc_packets++; + + return olen; +} + +/***************************/ +/*** Decompression stuff ***/ +/***************************/ +static inline u32 getbits(const u8 *buf, const u32 n, u32 *i, u32 *l) +{ + static const u32 m[] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff}; + u32 res, ol; + + ol = *l; + if (*l >= n) { + *l = (*l) - n; + res = (buf[*i] & m[ol]) >> (*l); + if (*l == 0) { + *l = 8; + (*i)++; + } + } else { + *l = 8 - n + (*l); + res = (buf[(*i)++] & m[ol]) << 8; + res = (res | buf[*i]) >> (*l); + } + + return res; +} + +static inline u32 getbyte(const u8 *buf, const u32 i, const u32 l) +{ + if (l == 8) { + return buf[i]; + } else { + return (((buf[i] << 8) | buf[i+1]) >> l) & 0xff; + } +} + +static inline void lamecopy(u8 *dst, u8 *src, u32 len) +{ + while (len--) + *dst++ = *src++; +} + +static int +mppc_decompress(struct ppp_mppe_state *state, unsigned char *ibuf, + unsigned char *obuf, int isize, int osize) +{ + u32 olen, off, len, bits, val, sig, i, l; + u8 *history, *s; + + history = state->hist + state->histptr; + olen = len = i = 0; + l = 8; + bits = isize * 8; + while (bits >= 8) { + val = getbyte(ibuf, i++, l); + if (val < 0x80) { /* literal byte < 0x80 */ + if (state->histptr < 2*MPPE_HIST_LEN) { + /* copy uncompressed byte to the history */ + (state->hist)[(state->histptr)++] = (u8) val; + } else { + /* buffer overflow; drop packet */ + if (state->debug) + printk(KERN_ERR "%s%d: trying to write outside history " + "buffer\n", __FUNCTION__, state->unit); + return DECOMP_ERROR; + } + olen++; + bits -= 8; + continue; + } + + sig = val & 0xc0; + if (sig == 0x80) { /* literal byte >= 0x80 */ + if (state->histptr < 2*MPPE_HIST_LEN) { + /* copy uncompressed byte to the history */ + (state->hist)[(state->histptr)++] = + (u8) (0x80|((val&0x3f)<<1)|getbits(ibuf, 1 , &i ,&l)); + } else { + /* buffer overflow; drop packet */ + if (state->debug) + printk(KERN_ERR "%s%d: trying to write outside history " + "buffer\n", __FUNCTION__, state->unit); + return DECOMP_ERROR; + } + olen++; + bits -= 9; + continue; + } + + /* Not a literal byte so it must be an (offset,length) pair */ + /* decode offset */ + sig = val & 0xf0; + if (sig == 0xf0) { /* 10-bit offset; 0 <= offset < 64 */ + off = (((val&0x0f)<<2)|getbits(ibuf, 2 , &i ,&l)); + bits -= 10; + } else { + if (sig == 0xe0) { /* 12-bit offset; 64 <= offset < 320 */ + off = ((((val&0x0f)<<4)|getbits(ibuf, 4 , &i ,&l))+64); + bits -= 12; + } else { + if ((sig&0xe0) == 0xc0) {/* 16-bit offset; 320 <= offset < 8192 */ + off = ((((val&0x1f)<<8)|getbyte(ibuf, i++, l))+320); + bits -= 16; + if (off > MPPE_HIST_LEN - 1) { + if (state->debug) + printk(KERN_DEBUG "%s%d: too big offset value: %d\n", + __FUNCTION__, state->unit, off); + return DECOMP_ERROR; + } + } else { /* this shouldn't happen */ + if (state->debug) + printk(KERN_DEBUG "%s%d: cannot decode offset value\n", + __FUNCTION__, state->unit); + return DECOMP_ERROR; + } + } + } + /* decode length of match */ + val = getbyte(ibuf, i, l); + if ((val & 0x80) == 0x00) { /* len = 3 */ + len = 3; + bits--; + getbits(ibuf, 1 , &i ,&l); + } else if ((val & 0xc0) == 0x80) { /* 4 <= len < 8 */ + len = 0x04 | ((val>>4) & 0x03); + bits -= 4; + getbits(ibuf, 4 , &i ,&l); + } else if ((val & 0xe0) == 0xc0) { /* 8 <= len < 16 */ + len = 0x08 | ((val>>2) & 0x07); + bits -= 6; + getbits(ibuf, 6 , &i ,&l); + } else if ((val & 0xf0) == 0xe0) { /* 16 <= len < 32 */ + len = 0x10 | (val & 0x0f); + bits -= 8; + i++; + } else { + bits -= 8; + val = (val << 8) | getbyte(ibuf, ++i, l); + if ((val & 0xf800) == 0xf000) { /* 32 <= len < 64 */ + len = 0x0020 | ((val >> 6) & 0x001f); + bits -= 2; + getbits(ibuf, 2 , &i ,&l); + } else if ((val & 0xfc00) == 0xf800) { /* 64 <= len < 128 */ + len = 0x0040 | ((val >> 4) & 0x003f); + bits -= 4; + getbits(ibuf, 4 , &i ,&l); + } else if ((val & 0xfe00) == 0xfc00) { /* 128 <= len < 256 */ + len = 0x0080 | ((val >> 2) & 0x007f); + bits -= 6; + getbits(ibuf, 6 , &i ,&l); + } else if ((val & 0xff00) == 0xfe00) { /* 256 <= len < 512 */ + len = 0x0100 | (val & 0x00ff); + bits -= 8; + i++; + } else { + bits -= 8; + val = (val << 8) | getbyte(ibuf, ++i, l); + if ((val & 0xff8000) == 0xff0000) { /* 512 <= len < 1024 */ + len = 0x000200 | ((val >> 6) & 0x0001ff); + bits -= 2; + getbits(ibuf, 2 , &i ,&l); + } else if ((val & 0xffc000) == 0xff8000) {/* 1024 <= len < 2048 */ + len = 0x000400 | ((val >> 4) & 0x0003ff); + bits -= 4; + getbits(ibuf, 4 , &i ,&l); + } else if ((val & 0xffe000) == 0xffc000) {/* 2048 <= len < 4096 */ + len = 0x000800 | ((val >> 2) & 0x0007ff); + bits -= 6; + getbits(ibuf, 6 , &i ,&l); + } else if ((val & 0xfff000) == 0xffe000) {/* 4096 <= len < 8192 */ + len = 0x001000 | (val & 0x000fff); + bits -= 8; + i++; + } else { /* this shouldn't happen */ + if (state->debug) + printk(KERN_DEBUG "%s%d: wrong length code: 0x%X\n", + __FUNCTION__, state->unit, val); + return DECOMP_ERROR; + } + } + } + s = state->hist + state->histptr; + state->histptr += len; + olen += len; + if (state->histptr < 2*MPPE_HIST_LEN) { + /* copy uncompressed bytes to the history */ + + /* In some cases len may be greater than off. It means that memory + * areas pointed by s and s-off overlap. I had used memmove() here + * because I thought that it acts as libc's version. Unfortunately, + * I was wrong. :-) I got strange errors sometimes. Wilfried suggested + * using of byte by byte copying here and strange errors disappeared. + */ + lamecopy(s, s - off, len); + } else { + /* buffer overflow; drop packet */ + if (state->debug) + printk(KERN_ERR "%s%d: trying to write outside history " + "buffer\n", __FUNCTION__, state->unit); + return DECOMP_ERROR; + } + } + + /* Do PFC decompression */ + len = olen; + if ((history[0] & 0x01) != 0) { + obuf[0] = 0; + obuf++; + len++; + } + + if (len <= osize) { + /* copy uncompressed packet to the output buffer */ + memcpy(obuf, history, olen); + } else { + /* buffer overflow; drop packet */ + if (state->debug) + printk(KERN_ERR "%s%d: too big uncompressed packet: %d\n", + __FUNCTION__, state->unit, len + (PPP_HDRLEN / 2)); + return DECOMP_ERROR; + } + + return (int) len; +} + +int +mppe_decompress(void *arg, unsigned char *ibuf, int isize, + unsigned char *obuf, int osize) +{ + struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg; + int seq, bits, uncomplen; + + if (isize <= PPP_HDRLEN + MPPE_OVHD) { + if (state->debug) { + printk(KERN_DEBUG "%s%d: short packet (len=%d)\n", __FUNCTION__, + state->unit, isize); + } + return DECOMP_ERROR; + } + + /* Get coherency counter and control bits from input buffer */ + seq = MPPE_CCOUNT(ibuf); + bits = MPPE_BITS(ibuf); + + if (state->stateless) { + /* RFC 3078, sec 8.1. */ + mppe_increase_ccount(state); + if ((seq != state->ccount) && state->debug) + printk(KERN_DEBUG "%s%d: bad sequence number: %d, expected: %d\n", + __FUNCTION__, state->unit, seq, state->ccount); + while (seq != state->ccount) + mppe_increase_ccount(state); + } else { + /* RFC 3078, sec 8.2. */ + if (state->flushexpected) { /* discard state */ + if ((bits & MPPE_BIT_FLUSHED)) { /* we received expected FLUSH bit */ + while (seq != state->ccount) + mppe_increase_ccount(state); + state->flushexpected = 0; + } else /* drop packet*/ + return DECOMP_ERROR; + } else { /* normal state */ + mppe_increase_ccount(state); + if (seq != state->ccount) { + /* Packet loss detected, enter the discard state. */ + if (state->debug) + printk(KERN_DEBUG "%s%d: bad sequence number: %d, expected: %d\n", + __FUNCTION__, state->unit, seq, state->ccount); + state->flushexpected = 1; + return DECOMP_ERROR; + } + } + if (state->mppe && (bits & MPPE_BIT_FLUSHED)) { + arc4_setkey(state, state->session_key, state->keylen); + } + } + + if (state->mppc && (bits & (MPPE_BIT_FLUSHED | MPPE_BIT_RESET))) { + state->histptr = MPPE_HIST_LEN; + if ((bits & MPPE_BIT_FLUSHED)) { + memset(state->hist + MPPE_HIST_LEN, 0, MPPE_HIST_LEN*sizeof(u8)); + } else + if ((bits & MPPE_BIT_RESET)) { + memcpy(state->hist, state->hist + MPPE_HIST_LEN, MPPE_HIST_LEN); + } + } + + /* Fill in the first part of the PPP header. The protocol field + comes from the decompressed data. */ + obuf[0] = PPP_ADDRESS(ibuf); + obuf[1] = PPP_CONTROL(ibuf); + obuf += PPP_HDRLEN / 2; + + if (state->mppe) { /* process encrypted packet */ + if ((bits & MPPE_BIT_ENCRYPTED)) { + /* OK, packet encrypted, so decrypt it */ + if (state->mppc && (bits & MPPE_BIT_COMP)) { + /* Hack warning !!! RC4 implementation which we use does + decryption "in place" - it means that input and output + buffers can be *the same* memory area. Therefore we don't + need to use a temporary buffer. But be careful - other + implementations don't have to be so nice. */ + arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), isize - + PPP_HDRLEN - (MPPE_OVHD / 2), ibuf + PPP_HDRLEN + + (MPPE_OVHD / 2)); + uncomplen = mppc_decompress(state, ibuf + PPP_HDRLEN + + (MPPE_OVHD / 2), obuf, isize - + PPP_HDRLEN - (MPPE_OVHD / 2), + osize - (PPP_HDRLEN / 2)); + if (uncomplen == DECOMP_ERROR) { + state->flushexpected = 1; + return DECOMP_ERROR; + } + uncomplen += PPP_HDRLEN / 2; + (state->stats).comp_bytes += isize; + (state->stats).comp_packets++; + } else { + uncomplen = isize - MPPE_OVHD; + /* Decrypt the first byte in order to check if it is + compressed or uncompressed protocol field */ + arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), 1, obuf); + /* Do PFC decompression */ + if ((obuf[0] & 0x01) != 0) { + obuf[1] = obuf[0]; + obuf[0] = 0; + obuf++; + uncomplen++; + } + /* And finally, decrypt the rest of the frame. */ + arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2) + 1, + isize - PPP_HDRLEN - (MPPE_OVHD / 2) - 1, obuf + 1); + (state->stats).inc_bytes += isize; + (state->stats).inc_packets++; + } + } else { /* this shouldn't happen */ + if (state->debug) + printk(KERN_ERR "%s%d: encryption negotiated but not an " + "encrypted packet received\n", __FUNCTION__, state->unit); + mppe_change_key(state, 0); + state->flushexpected = 1; + return DECOMP_ERROR; + } + } else { + if (state->mppc) { /* no MPPE, only MPPC */ + if ((bits & MPPE_BIT_COMP)) { + uncomplen = mppc_decompress(state, ibuf + PPP_HDRLEN + + (MPPE_OVHD / 2), obuf, isize - + PPP_HDRLEN - (MPPE_OVHD / 2), + osize - (PPP_HDRLEN / 2)); + if (uncomplen == DECOMP_ERROR) { + state->flushexpected = 1; + return DECOMP_ERROR; + } + uncomplen += PPP_HDRLEN / 2; + (state->stats).comp_bytes += isize; + (state->stats).comp_packets++; + } else { + memcpy(obuf, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), isize - + PPP_HDRLEN - (MPPE_OVHD / 2)); + uncomplen = isize - MPPE_OVHD; + (state->stats).inc_bytes += isize; + (state->stats).inc_packets++; + } + } else { /* this shouldn't happen */ + if (state->debug) + printk(KERN_ERR "%s%d: error - not an MPPC or MPPE frame " + "received\n", __FUNCTION__, state->unit); + state->flushexpected = 1; + return DECOMP_ERROR; + } + } + + (state->stats).unc_bytes += uncomplen; + (state->stats).unc_packets++; + + return uncomplen; +} + + +/************************************************************ + * Module interface table + ************************************************************/ + +/* These are in ppp_generic.c */ +extern int ppp_register_compressor (struct compressor *cp); +extern void ppp_unregister_compressor (struct compressor *cp); + +/* + * Functions exported to ppp_generic.c. + * + * In case of MPPC/MPPE there is no need to process incompressible data + * because such a data is sent in MPPC/MPPE frame. Therefore the (*incomp) + * callback function isn't needed. + */ +struct compressor ppp_mppe = { + CI_MPPE, /* compress_proto */ + mppe_comp_alloc, /* comp_alloc */ + mppe_comp_free, /* comp_free */ + mppe_comp_init, /* comp_init */ + mppe_comp_reset, /* comp_reset */ + mppe_compress, /* compress */ + mppe_stats, /* comp_stat */ + mppe_decomp_alloc, /* decomp_alloc */ + mppe_comp_free, /* decomp_free */ + mppe_decomp_init, /* decomp_init */ + mppe_decomp_reset, /* decomp_reset */ + mppe_decompress, /* decompress */ + NULL, /* incomp */ + mppe_stats, /* decomp_stat */ +}; + +/************************************************************ + * Module support routines + ************************************************************/ + +int __init mppe_module_init(void) +{ + int answer; + + /* When the module is compiled into kernel, it is initialized before + * CryptoAPI. Therefore the code below reports that there is no crypto + * stuff in the kernel. Marlon de Boer who has pointed out the problem, + * has sent also a message to CryptoAPI developers, so maybe in the future + * the code will be uncommented. + * + if (!(crypto_alg_available("arc4", 0) && crypto_alg_available("sha1", 0))) { + printk(KERN_ERR "Kernel doesn't provide ARC4 and/or SHA1 algorithms " + "required by MPPE/MPPC. Check CryptoAPI configuration.\n"); + return -ENODEV; + } + */ + + /* Allocate space for SHAPad1, SHAPad2 and ... */ + sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL); + if (sha_pad == NULL) + return -ENOMEM; + /* ... initialize them */ + memset(sha_pad->sha_pad1, 0x00, sizeof(sha_pad->sha_pad1)); + memset(sha_pad->sha_pad2, 0xf2, sizeof(sha_pad->sha_pad2)); + + answer = ppp_register_compressor(&ppp_mppe); + if (answer == 0) { + printk(KERN_INFO "MPPE/MPPC encryption/compression module registered\n"); + } + return answer; +} + +void __exit mppe_module_cleanup(void) +{ + kfree(sha_pad); + ppp_unregister_compressor(&ppp_mppe); + printk(KERN_INFO "MPPE/MPPC encryption/compression module unregistered\n"); +} + +module_init(mppe_module_init); +module_exit(mppe_module_cleanup); + +MODULE_AUTHOR("Jan Dubiec "); +MODULE_DESCRIPTION("MPPE/MPPC encryption/compression module for Linux"); +MODULE_LICENSE("Dual BSD/GPL"); --- a/include/linux/ppp-comp.h +++ b/include/linux/ppp-comp.h @@ -28,7 +28,7 @@ */ /* - * ==FILEVERSION 980319== + * ==FILEVERSION 20040509== * * NOTE TO MAINTAINERS: * If you modify this file at all, please set the above date. @@ -78,7 +78,7 @@ struct compressor { /* Compress a packet */ int (*compress) (void *state, unsigned char *rptr, - unsigned char *obuf, int isize, int osize); + unsigned char *obuf, int isize, int osize); /* Return compression statistics */ void (*comp_stat) (void *state, struct compstat *stats); @@ -99,7 +99,7 @@ struct compressor { /* Decompress a packet. */ int (*decompress) (void *state, unsigned char *ibuf, int isize, - unsigned char *obuf, int osize); + unsigned char *obuf, int osize); /* Update state for an incompressible packet received */ void (*incomp) (void *state, unsigned char *ibuf, int icnt); @@ -187,6 +187,42 @@ struct compressor { #define DEFLATE_CHK_SEQUENCE 0 /* + * Definitions for MPPE/MPPC. + */ + +#define CI_MPPE 18 /* config option for MPPE */ +#define CILEN_MPPE 6 /* length of config option */ + +#define MPPE_OVHD 4 /* MPPE overhead */ +#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */ + +#define MPPE_STATELESS 0x01 /* configuration bit H */ +#define MPPE_40BIT 0x20 /* configuration bit L */ +#define MPPE_56BIT 0x80 /* configuration bit M */ +#define MPPE_128BIT 0x40 /* configuration bit S */ +#define MPPE_MPPC 0x01 /* configuration bit C */ + +/* + * Definitions for Stac LZS. + */ + +#define CI_LZS 17 /* config option for Stac LZS */ +#define CILEN_LZS 5 /* length of config option */ + +#define LZS_OVHD 4 /* max. LZS overhead */ +#define LZS_HIST_LEN 2048 /* LZS history size */ +#define LZS_MAX_CCOUNT 0x0FFF /* max. coherency counter value */ + +#define LZS_MODE_NONE 0 +#define LZS_MODE_LCB 1 +#define LZS_MODE_CRC 2 +#define LZS_MODE_SEQ 3 +#define LZS_MODE_EXT 4 + +#define LZS_EXT_BIT_FLUSHED 0x80 /* bit A */ +#define LZS_EXT_BIT_COMP 0x20 /* bit C */ + +/* * Definitions for other, as yet unsupported, compression methods. */