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openwrt-mirror/target/linux/generic-2.4/patches/106-mppe_mppc.patch

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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
Index: linux-2.4.35.4/Documentation/Configure.help
===================================================================
--- linux-2.4.35.4.orig/Documentation/Configure.help 2007-12-15 05:19:49.287229757 +0100
+++ linux-2.4.35.4/Documentation/Configure.help 2007-12-15 05:19:51.927380210 +0100
@@ -9974,6 +9974,28 @@
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.
Index: linux-2.4.35.4/crypto/Config.in
===================================================================
--- linux-2.4.35.4.orig/crypto/Config.in 2007-12-15 05:19:42.094819886 +0100
+++ linux-2.4.35.4/crypto/Config.in 2007-12-15 05:19:51.927380210 +0100
@@ -11,7 +11,9 @@
"$CONFIG_INET6_AH" = "y" -o \
"$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 \
+ "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then
define_bool CONFIG_CRYPTO y
else
bool 'Cryptographic API' CONFIG_CRYPTO
@@ -51,11 +53,24 @@
"$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 \
+ "$CONFIG_CRYPTO_SHA1" != "m" ]; then
+ define_tristate CONFIG_CRYPTO_SHA1 m
+ fi
+ fi
fi
+ tristate ' SHA1 digest algorithm' CONFIG_CRYPTO_SHA1
+
tristate ' SHA256 digest algorithm' CONFIG_CRYPTO_SHA256
tristate ' SHA384 and SHA512 digest algorithms' CONFIG_CRYPTO_SHA512
tristate ' Whirlpool digest algorithms' CONFIG_CRYPTO_WP512
@@ -76,7 +91,20 @@
tristate ' TEA and XTEA cipher algorithms' CONFIG_CRYPTO_TEA
tristate ' Khazad cipher algorithm' CONFIG_CRYPTO_KHAZAD
tristate ' Anubis cipher algorithm' CONFIG_CRYPTO_ANUBIS
+
+ if [ "$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 \
Index: linux-2.4.35.4/drivers/net/Config.in
===================================================================
--- linux-2.4.35.4.orig/drivers/net/Config.in 2007-12-15 05:19:42.102820341 +0100
+++ linux-2.4.35.4/drivers/net/Config.in 2007-12-15 05:19:51.931380439 +0100
@@ -336,6 +336,7 @@
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 $CONFIG_PPP
fi
Index: linux-2.4.35.4/drivers/net/Makefile
===================================================================
--- linux-2.4.35.4.orig/drivers/net/Makefile 2007-12-15 05:19:42.110820796 +0100
+++ linux-2.4.35.4/drivers/net/Makefile 2007-12-15 05:19:51.931380439 +0100
@@ -166,6 +166,7 @@
obj-$(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
Index: linux-2.4.35.4/drivers/net/ppp_generic.c
===================================================================
--- linux-2.4.35.4.orig/drivers/net/ppp_generic.c 2007-12-15 05:19:42.114821025 +0100
+++ linux-2.4.35.4/drivers/net/ppp_generic.c 2007-12-15 05:19:51.931380439 +0100
@@ -19,7 +19,7 @@
* PPP driver, written by Michael Callahan and Al Longyear, and
* subsequently hacked by Paul Mackerras.
*
- * ==FILEVERSION 20020217==
+ * ==FILEVERSION 20040509==
*/
#include <linux/config.h>
@@ -102,6 +102,7 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
/* 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)
Index: linux-2.4.35.4/drivers/net/ppp_mppe_mppc.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.4.35.4/drivers/net/ppp_mppe_mppc.c 2007-12-15 05:19:51.935380668 +0100
@@ -0,0 +1,1312 @@
+/*
+ * ppp_mppe_mppc.c - MPPC/MPPE "compressor/decompressor" module.
+ *
+ * Copyright (c) 1994 <20>rp<72>d Magos<6F>nyi <mag@bunuel.tii.matav.hu>
+ * Copyright (c) 1999 Tim Hockin, Cobalt Networks Inc. <thockin@cobaltnet.com>
+ * Copyright (c) 2002-2005 Jan Dubiec <jdx@slackware.pl>
+ *
+ * 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 <20>rp<72>d Magos<6F>nyi 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 <linux/init.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/scatterlist.h>
+#include <linux/vmalloc.h>
+#include <linux/crypto.h>
+
+#include <linux/ppp_defs.h>
+#include <linux/ppp-comp.h>
+
+/*
+ * 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 <jdx@slackware.pl>");
+MODULE_DESCRIPTION("MPPE/MPPC encryption/compression module for Linux");
+MODULE_LICENSE("Dual BSD/GPL");
Index: linux-2.4.35.4/include/linux/ppp-comp.h
===================================================================
--- linux-2.4.35.4.orig/include/linux/ppp-comp.h 2007-12-15 05:19:42.134822165 +0100
+++ linux-2.4.35.4/include/linux/ppp-comp.h 2007-12-15 05:19:51.935380668 +0100
@@ -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 @@
/* 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 @@
/* 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 @@
#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.
*/
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