--- /dev/null
+/*
+ * arcfour.c
+ * by Frank Cusack <frank@google.com>
+ * 100% public domain
+ *
+ * Implemented from the description in _Applied Cryptography_, 2nd ed.
+ *
+ * ** Distribution ** of this software is unlimited and unrestricted.
+ *
+ * ** Use ** of this software is almost certainly legal; however, refer
+ * to <http://theory.lcs.mit.edu/~rivest/faq.html>.
+ */
+
+#include "arcfour.h"
+
+#define swap(a, b) \
+{ \
+ unsigned char t = b; \
+ b = a; \
+ a = t; \
+}
+
+/*
+ * Initialize arcfour from a key.
+ */
+void
+arcfour_setkey(arcfour_context *context, const unsigned char *key,
+ unsigned keylen)
+{
+ unsigned i, j;
+ unsigned char K[256];
+
+ context->i = context->j = 0;
+
+ for (i = 0; i < 256; i++) {
+ context->S[i] = i;
+ K[i] = key[i % keylen];
+ }
+
+ j = 0;
+ for (i = 0; i < 256; i++) {
+ j = (j + context->S[i] + K[i]) % 256;
+ swap(context->S[i], context->S[j]);
+ }
+
+ memset(K, 0, sizeof(K));
+}
+
+/*
+ * plaintext -> ciphertext (or vice versa)
+ */
+void
+arcfour_encrypt(arcfour_context *context, const unsigned char *in, unsigned len,
+ unsigned char *out)
+{
+ unsigned i = context->i;
+ unsigned j = context->j;
+ unsigned char *S = context->S;
+ unsigned char K;
+
+ while (len--) {
+ i = (i + 1) % 256;
+ j = (j + S[i]) % 256;
+ swap(S[i], S[j]);
+ K = S[(S[i] + S[j]) % 256];
+ *out++ = *in++ ^ K;
+ }
+
+ context->i = i;
+ context->j = j;
+}
+
--- /dev/null
+/* arcfour.h */
+
+#ifndef _ARCFOUR_H
+#define _ARCFOUR_H
+
+typedef struct {
+ unsigned i;
+ unsigned j;
+ unsigned char S[256];
+} arcfour_context;
+
+extern void arcfour_setkey(arcfour_context *, const unsigned char *, unsigned);
+extern void arcfour_encrypt(arcfour_context *, const unsigned char *, unsigned,
+ unsigned char *);
+#define arcfour_decrypt arcfour_encrypt
+
+#endif /* _ARCFOUR_H */
--- /dev/null
+--- linux-2.2.20/include/linux/ppp-comp.h.orig Sun Mar 25 08:31:04 2001
++++ linux-2.2.20/include/linux/ppp-comp.h Tue Mar 19 09:39:19 2002
+@@ -187,6 +187,100 @@
+ #define DEFLATE_CHK_SEQUENCE 0
+
+ /*
++ * Definitions for MPPE.
++ */
++
++#define CI_MPPE 18 /* config option for MPPE */
++#define CILEN_MPPE 6 /* length of config option */
++
++#define MPPE_PAD 4 /* MPPE growth per frame */
++#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
++
++/* option bits for ccp_options.mppe */
++#define MPPE_OPT_40 0x01 /* 40 bit */
++#define MPPE_OPT_128 0x02 /* 128 bit */
++#define MPPE_OPT_STATEFUL 0x04 /* stateful mode */
++/* unsupported opts */
++#define MPPE_OPT_56 0x08 /* 56 bit */
++#define MPPE_OPT_MPPC 0x10 /* MPPC compression */
++#define MPPE_OPT_D 0x20 /* Unknown */
++#define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
++#define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */
++
++/*
++ * This is not nice ... the alternative is a bitfield struct though.
++ * And unfortunately, we cannot share the same bits for the option
++ * names above since C and H are the same bit. We could do a u_int32
++ * but then we have to do a htonl() all the time and/or we still need
++ * to know which octet is which.
++ */
++#define MPPE_C_BIT 0x01 /* MPPC */
++#define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */
++#define MPPE_L_BIT 0x20 /* 40-bit */
++#define MPPE_S_BIT 0x40 /* 128-bit */
++#define MPPE_M_BIT 0x80 /* 56-bit, not supported */
++#define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */
++
++/* Does not include H bit; used for least significant octet only. */
++#define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
++
++/* Build a CI from mppe opts (see RFC 3078) */
++#define MPPE_OPTS_TO_CI(opts, ci) \
++ do { \
++ u_char *ptr = ci; /* u_char[4] */ \
++ \
++ /* H bit */ \
++ if (opts & MPPE_OPT_STATEFUL) \
++ *ptr++ = 0x0; \
++ else \
++ *ptr++ = MPPE_H_BIT; \
++ *ptr++ = 0; \
++ *ptr++ = 0; \
++ \
++ /* S,L bits */ \
++ *ptr = 0; \
++ if (opts & MPPE_OPT_128) \
++ *ptr |= MPPE_S_BIT; \
++ if (opts & MPPE_OPT_40) \
++ *ptr |= MPPE_L_BIT; \
++ /* M,D,C bits not supported */ \
++ } while (/* CONSTCOND */ 0)
++
++/* The reverse of the above */
++#define MPPE_CI_TO_OPTS(ci, opts) \
++ do { \
++ u_char *ptr = ci; /* u_char[4] */ \
++ \
++ opts = 0; \
++ \
++ /* H bit */ \
++ if (!(ptr[0] & MPPE_H_BIT)) \
++ opts |= MPPE_OPT_STATEFUL; \
++ \
++ /* S,L bits */ \
++ if (ptr[3] & MPPE_S_BIT) \
++ opts |= MPPE_OPT_128; \
++ if (ptr[3] & MPPE_L_BIT) \
++ opts |= MPPE_OPT_40; \
++ \
++ /* M,D,C bits */ \
++ if (ptr[3] & MPPE_M_BIT) \
++ opts |= MPPE_OPT_56; \
++ if (ptr[3] & MPPE_D_BIT) \
++ opts |= MPPE_OPT_D; \
++ if (ptr[3] & MPPE_C_BIT) \
++ opts |= MPPE_OPT_MPPC; \
++ \
++ /* Other bits */ \
++ if (ptr[0] & ~MPPE_H_BIT) \
++ opts |= MPPE_OPT_UNKNOWN; \
++ if (ptr[1] || ptr[2]) \
++ opts |= MPPE_OPT_UNKNOWN; \
++ if (ptr[3] & ~MPPE_ALL_BITS) \
++ opts |= MPPE_OPT_UNKNOWN; \
++ } while (/* CONSTCOND */ 0)
++
++/*
+ * Definitions for other, as yet unsupported, compression methods.
+ */
+
--- /dev/null
+--- linux/drivers/net/Makefile.orig Fri Nov 2 08:39:07 2001
++++ linux/drivers/net/Makefile Tue Mar 19 09:31:06 2002
+@@ -325,11 +325,13 @@
+ CONFIG_BSDCOMP_BUILTIN = y
+ CONFIG_SLHC_BUILTIN = y
+ CONFIG_PPPDEF_BUILTIN = y
++CONFIG_PPPMPPE_BUILTIN = y
+ else
+ ifeq ($(CONFIG_PPP),m)
+ CONFIG_BSDCOMP_MODULE = y
+ CONFIG_SLHC_MODULE = y
+ CONFIG_PPPDEF_MODULE = y
++ CONFIG_PPPMPPE_MODULE = y
+ MX_OBJS += ppp.o
+ endif
+ endif
+@@ -1100,6 +1102,17 @@
+ endif
+ endif
+
++# If anything built-in uses ppp_mppe, then build it into the kernel also.
++# If not, but a module uses it, build as a module.
++ifdef CONFIG_PPPMPPE_BUILTIN
++L_OBJS += ppp_mppe_compress.o arcfour.o sha1.o
++else
++ ifdef CONFIG_PPPMPPE_MODULE
++ PPPMPPE_OBJS = ppp_mppe_compress.o arcfour.o sha1.o
++ M_OBJS += ppp_mppe.o
++ endif
++endif
++
+ ifeq ($(CONFIG_ARIADNE2),y)
+ L_OBJS += ariadne2.o
+ CONFIG_8390_BUILTIN = y
+@@ -1449,3 +1462,8 @@
+
+ rcpci.o: rcpci45.o rclanmtl.o
+ $(LD) -r -o rcpci.o rcpci45.o rclanmtl.o
++
++ifdef CONFIG_PPPMPPE_MODULE
++ppp_mppe.o: $(PPPMPPE_OBJS)
++ $(LD) -r -o $@ $(PPPMPPE_OBJS)
++endif
--- /dev/null
+--- linux/drivers/net/ppp.c.orig Sun Mar 25 08:31:15 2001
++++ linux/drivers/net/ppp.c Tue Mar 19 07:15:40 2002
+@@ -2468,10 +2468,14 @@
+ (proto != PPP_LCP) &&
+ (proto != PPP_CCP)) {
+ struct sk_buff *new_skb;
++ int new_skb_size = ppp->mtu + PPP_HDRLEN;
+ int new_count;
+
+ /* Allocate an skb for the compressed frame. */
+- new_skb = alloc_skb(ppp->mtu + PPP_HDRLEN, GFP_ATOMIC);
++ if (ppp->sc_xcomp->compress_proto == CI_MPPE)
++ /* CCP [must have] reduced MTU by MPPE_PAD. */
++ new_skb_size += MPPE_PAD;
++ new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
+ if (new_skb == NULL) {
+ printk(KERN_ERR "ppp_send_frame: no memory\n");
+ kfree_skb(skb);
+@@ -2489,12 +2493,25 @@
+ skb_put(new_skb, new_count);
+ kfree_skb(skb);
+ skb = new_skb;
+- } else {
++ } else if (new_count == 0) {
+ /*
+ * The frame could not be compressed, or it could not
+ * be sent in compressed form because CCP is down.
+ */
+ kfree_skb(new_skb);
++ } else {
++ /*
++ * (new_count < 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);
++ ppp->xmit_busy = 0;
++ return;
+ }
+ }
+
--- /dev/null
+--- modutils-2.3.21.orig/util/alias.h Tue Mar 19 21:23:02 2002
++++ modutils-2.3.21/util/alias.h Tue Mar 19 21:25:55 2002
+@@ -162,6 +162,7 @@
+ "slip1 slip",
+ "tty-ldisc-1 slip",
+ "tty-ldisc-3 ppp",
++ "ppp-compress-18 ppp_mppe",
+ "ppp-compress-21 bsd_comp",
+ "ppp-compress-24 ppp_deflate",
+ "ppp-compress-26 ppp_deflate",
--- /dev/null
+#!/bin/sh
+#
+# A quickie script to install MPPE into the 2.2.20 kernel.
+# Does no error checking!!!
+#
+
+mppe_files="sha1.[ch] arcfour.[ch] ppp_mppe.c"
+
+[ $1 ] || exit 1
+[ -d "$1" ] || exit 1
+
+echo "I will now patch the kernel in directory $1"
+echo -n "Press ret to continue, CTRL-C to exit: "
+read
+
+patchdir=`pwd`
+pushd "$1" >/dev/null
+for patch in $patchdir/linux*.patch; do
+ patch -p1 < $patch
+done
+
+for file in $mppe_files; do
+ cp $patchdir/$file drivers/net
+done
+
+popd >/dev/null
+
+exit 0
--- /dev/null
+/*
+ * ==FILEVERSION 20020320==
+ *
+ * ppp_mppe_compress.c - interface MPPE to the PPP code.
+ * This version is for use with Linux kernel 2.2.x (ppp driver 2.3.x).
+ *
+ * By Frank Cusack <frank@google.com>.
+ * Copyright (c) 2002 Google, Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/malloc.h>
+#include <linux/string.h>
+
+#include <linux/ppp_defs.h>
+#include <linux/ppp-comp.h>
+
+#include "arcfour.h"
+#include "sha1.h"
+
+/*
+ * State for an MPPE (de)compressor.
+ */
+typedef struct ppp_mppe_state {
+ unsigned char master_key[MPPE_MAX_KEY_LEN];
+ unsigned char session_key[MPPE_MAX_KEY_LEN];
+ arcfour_context arcfour_context; /* encryption state */
+ unsigned keylen; /* key length in bytes */
+ /* NB: 128-bit == 16, 40-bit == 8! */
+ /* If we want to support 56-bit, */
+ /* the unit has to change to bits */
+ unsigned char bits; /* MPPE control bits */
+ unsigned ccount; /* 12-bit coherency count (seqno) */
+ unsigned stateful; /* stateful mode flag */
+ int discard; /* stateful mode packet loss flag */
+ int sanity_errors; /* take down LCP if too many */
+ int unit;
+ int debug;
+ struct compstat stats;
+} ppp_mppe_state;
+
+/* ppp_mppe_state.bits definitions */
+#define MPPE_BIT_A 0x80 /* Encryption table were (re)inititalized */
+#define MPPE_BIT_B 0x40 /* MPPC only (not implemented) */
+#define MPPE_BIT_C 0x20 /* MPPC only (not implemented) */
+#define MPPE_BIT_D 0x10 /* This is an encrypted frame */
+
+#define MPPE_BIT_FLUSHED MPPE_BIT_A
+#define MPPE_BIT_ENCRYPTED MPPE_BIT_D
+
+#define MPPE_BITS(p) ((p)[4] & 0xf0)
+#define MPPE_CCOUNT(p) ((((p)[4] & 0x0f) << 8) + (p)[5])
+#define MPPE_CCOUNT_SPACE 0x1000 /* The size of the ccount space */
+
+/*
+ * MPPE overhead/packet.
+ * Note that we use this differently than other compressors.
+ */
+#define MPPE_OVHD 2 /* MPPE overhead/packet */
+/* Max bogon factor we will tolerate */
+#define SANITY_MAX 1600
+
+static void GetNewKeyFromSHA __P((unsigned char *StartKey,
+ unsigned char *SessionKey,
+ unsigned SessionKeyLength,
+ unsigned char *InterimKey));
+static void mppe_rekey __P((ppp_mppe_state *state, int));
+static void *mppe_alloc __P((unsigned char *options, int optlen));
+static void mppe_free __P((void *state));
+static int mppe_init __P((void *state, unsigned char *options,
+ int optlen, int unit, int debug, const char *));
+static int mppe_comp_init __P((void *state, unsigned char *options,
+ int optlen,
+ int unit, int hdrlen, int debug));
+static int mppe_decomp_init __P((void *state, unsigned char *options,
+ int optlen, int unit,
+ int hdrlen, int mru, int debug));
+static int mppe_compress __P((void *state, unsigned char *ibuf,
+ unsigned char *obuf,
+ int isize, int osize));
+static void mppe_incomp __P((void *state, unsigned char *ibuf, int icnt));
+static int mppe_decompress __P((void *state, unsigned char *ibuf,
+ int isize, unsigned char *obuf,int osize));
+static void mppe_comp_reset __P((void *state));
+static void mppe_decomp_reset __P((void *state));
+static void mppe_comp_stats __P((void *state, struct compstat *stats));
+
+
+/*
+ * Key Derivation, from RFC 3078, RFC 3079.
+ * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
+ */
+static void
+GetNewKeyFromSHA(unsigned char *MasterKey, unsigned char *SessionKey,
+ unsigned SessionKeyLength, unsigned char *InterimKey)
+{
+ SHA1_CTX Context;
+ unsigned char Digest[SHA1_SIGNATURE_SIZE];
+
+ unsigned char SHApad1[40] =
+ { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+ unsigned char SHApad2[40] =
+ { 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+ 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+ 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+ 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2 };
+
+ /* assert(SessionKeyLength <= SHA1_SIGNATURE_SIZE); */
+
+ SHA1_Init(&Context);
+ SHA1_Update(&Context, MasterKey, SessionKeyLength);
+ SHA1_Update(&Context, SHApad1, sizeof(SHApad1));
+ SHA1_Update(&Context, SessionKey, SessionKeyLength);
+ SHA1_Update(&Context, SHApad2, sizeof(SHApad2));
+ SHA1_Final(Digest, &Context);
+
+ memcpy(InterimKey, Digest, SessionKeyLength);
+}
+
+/*
+ * Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3.
+ * Well, not what's written there, but rather what they meant.
+ */
+static void
+mppe_rekey(ppp_mppe_state *state, int initial_key)
+{
+ unsigned char InterimKey[MPPE_MAX_KEY_LEN];
+
+ GetNewKeyFromSHA(state->master_key, state->session_key,
+ state->keylen, InterimKey);
+ if (!initial_key) {
+ arcfour_setkey(&state->arcfour_context, InterimKey, state->keylen);
+ arcfour_encrypt(&state->arcfour_context, InterimKey, state->keylen,
+ state->session_key);
+ } else {
+ memcpy(state->session_key, InterimKey, state->keylen);
+ }
+ if (state->keylen == 8) {
+ /* See RFC 3078 */
+ state->session_key[0] = 0xd1;
+ state->session_key[1] = 0x26;
+ state->session_key[2] = 0x9e;
+ }
+ arcfour_setkey(&state->arcfour_context, state->session_key, state->keylen);
+}
+
+
+/*
+ * Allocate space for a (de)compressor.
+ */
+static void *
+mppe_alloc(unsigned char *options, int optlen)
+{
+ ppp_mppe_state *state;
+
+ if (optlen != CILEN_MPPE + sizeof(state->master_key)
+ || options[0] != CI_MPPE
+ || options[1] != CILEN_MPPE)
+ return NULL;
+
+ state = (ppp_mppe_state *) kmalloc(sizeof(*state), GFP_KERNEL);
+ if (state == NULL)
+ return NULL;
+
+ MOD_INC_USE_COUNT;
+ memset(state, 0, sizeof(*state));
+
+ /* Save keys. */
+ memcpy(state->master_key, &options[CILEN_MPPE], sizeof(state->master_key));
+ memcpy(state->session_key, state->master_key, sizeof(state->master_key));
+ /*
+ * We defer initial key generation until mppe_init(), as mppe_alloc()
+ * is called frequently during negotiation.
+ */
+
+ return (void *) state;
+}
+
+/*
+ * Deallocate space for a (de)compressor.
+ */
+static void
+mppe_free(void *arg)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+
+ if (state) {
+ kfree(state);
+ MOD_DEC_USE_COUNT;
+ }
+}
+
+
+/*
+ * Initialize (de)compressor state.
+ */
+static int
+mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug,
+ const char *debugstr)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+ unsigned char mppe_opts;
+
+ if (optlen != CILEN_MPPE
+ || options[0] != CI_MPPE
+ || options[1] != CILEN_MPPE)
+ return 0;
+
+ MPPE_CI_TO_OPTS(&options[2], mppe_opts);
+ if (mppe_opts & MPPE_OPT_128)
+ state->keylen = 16;
+ else if (mppe_opts & MPPE_OPT_40)
+ state->keylen = 8;
+ else {
+ printk(KERN_WARNING "%s[%d]: unknown key length\n", debugstr, unit);
+ return 0;
+ }
+ if (mppe_opts & MPPE_OPT_STATEFUL)
+ state->stateful = 1;
+
+ /* Generate the initial session key. */
+ mppe_rekey(state, 1);
+
+ if (debug) {
+ int i;
+ char mkey[sizeof(state->master_key) * 3 + 1];
+ char skey[sizeof(state->session_key) * 3 + 1];
+
+ printk(KERN_DEBUG "%s[%d]: initialized with %d-bit %s mode\n", debugstr,
+ unit, (state->keylen == 16)? 128: 40,
+ (state->stateful)? "stateful": "stateless");
+
+ for (i = 0; i < sizeof(state->master_key); i++)
+ sprintf(mkey + i * 2, "%.2x ", state->master_key[i]);
+ for (i = 0; i < sizeof(state->session_key); i++)
+ sprintf(skey + i * 2, "%.2x ", state->session_key[i]);
+ printk(KERN_DEBUG "%s[%d]: keys: master: %s initial session: %s\n",
+ debugstr, unit, mkey, skey);
+ }
+
+ /*
+ * Initialize the coherency count. The initial value is not specified
+ * in RFC 3078, but we can make a reasonable assumption that it will
+ * start at 0. Setting it to the max here makes the comp/decomp code
+ * do the right thing (determined through experiment).
+ */
+ state->ccount = MPPE_CCOUNT_SPACE - 1;
+
+ /*
+ * Note that even though we have initialized the key table, we don't
+ * set the FLUSHED bit. This is contrary to RFC 3078, sec. 3.1.
+ */
+ state->bits = MPPE_BIT_ENCRYPTED;
+
+ state->unit = unit;
+ state->debug = debug;
+
+ return 1;
+}
+
+
+
+static int
+mppe_comp_init(void *arg, unsigned char *options, int optlen, int unit,
+ int hdrlen, int debug)
+{
+ /* ARGSUSED */
+ return mppe_init(arg, options, optlen, unit, debug, "mppe_comp_init");
+}
+
+/*
+ * We received a CCP Reset-Request (actually, we are sending a Reset-Ack),
+ * tell the compressor to rekey. Note that we MUST NOT rekey for
+ * every CCP Reset-Request; we only rekey on the next xmit packet.
+ * We might get multiple CCP Reset-Requests if our CCP Reset-Ack is lost.
+ * So, rekeying for every CCP Reset-Request is broken as the peer will not
+ * know how many times we've rekeyed. (If we rekey and THEN get another
+ * CCP Reset-Request, we must rekey again.)
+ */
+static void
+mppe_comp_reset(void *arg)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+
+ state->bits |= MPPE_BIT_FLUSHED;
+}
+
+/*
+ * Compress (encrypt) a packet.
+ * It's strange to call this a compressor, since the output is always
+ * MPPE_OVHD + 2 bytes larger than the input.
+ */
+int
+mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
+ int isize, int osize)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+ int proto;
+
+ /*
+ * Check that the protocol is in the range we handle.
+ */
+ proto = PPP_PROTOCOL(ibuf);
+ if (proto < 0x0021 || proto > 0x00fa)
+ return 0;
+
+ /* Make sure we have enough room to generate an encrypted packet. */
+ if (osize < isize + MPPE_OVHD + 2) {
+ /* Drop the packet if we should encrypt it, but can't. */
+ printk(KERN_DEBUG "mppe_compress[%d]: osize too small! "
+ "(have: %d need: %d)\n", state->unit,
+ osize, osize + MPPE_OVHD + 2);
+ return -1;
+ }
+
+ osize = isize + MPPE_OVHD + 2;
+
+ /*
+ * Copy over the PPP header and set control bits.
+ */
+ obuf[0] = PPP_ADDRESS(ibuf);
+ obuf[1] = PPP_CONTROL(ibuf);
+ obuf[2] = PPP_COMP >> 8; /* isize + MPPE_OVHD + 1 */
+ obuf[3] = PPP_COMP; /* isize + MPPE_OVHD + 2 */
+ obuf += PPP_HDRLEN;
+
+ state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
+ obuf[0] = state->ccount >> 8;
+ obuf[1] = state->ccount & 0xff;
+
+ if (!state->stateful || /* stateless mode */
+ ((state->ccount & 0xff) == 0xff) || /* "flag" packet */
+ (state->bits & MPPE_BIT_FLUSHED)) { /* CCP Reset-Request */
+ /* We must rekey */
+ if (state->debug && state->stateful)
+ printk(KERN_DEBUG "mppe_compress[%d]: rekeying\n", state->unit);
+ mppe_rekey(state, 0);
+ state->bits |= MPPE_BIT_FLUSHED;
+ }
+ obuf[0] |= state->bits;
+ state->bits &= ~MPPE_BIT_FLUSHED; /* reset for next xmit */
+
+ obuf += MPPE_OVHD;
+ ibuf += 2; /* skip to proto field */
+ isize -= 2;
+
+ /* Encrypt packet */
+ arcfour_encrypt(&state->arcfour_context, ibuf, isize, obuf);
+
+ state->stats.unc_bytes += isize;
+ state->stats.unc_packets++;
+ state->stats.comp_bytes += osize;
+ state->stats.comp_packets++;
+
+ return osize;
+}
+
+/*
+ * Since every frame grows by MPPE_OVHD + 2 bytes, this is always going
+ * to look bad ... and the longer the link is up the worse it will get.
+ */
+static void
+mppe_comp_stats(void *arg, struct compstat *stats)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+
+ *stats = state->stats;
+}
+
+
+static int
+mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit,
+ int hdrlen, int mru, int debug)
+{
+ /* ARGSUSED */
+ return mppe_init(arg, options, optlen, unit, debug, "mppe_decomp_init");
+}
+
+/*
+ * We received a CCP Reset-Ack. Just ignore it.
+ */
+static void
+mppe_decomp_reset(void *arg)
+{
+ /* ARGSUSED */
+ return;
+}
+
+/*
+ * Decompress (decrypt) an MPPE packet.
+ */
+int
+mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf,
+ int osize)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+ unsigned ccount;
+ int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED;
+ int sanity = 0;
+
+ if (isize <= PPP_HDRLEN + MPPE_OVHD) {
+ if (state->debug)
+ printk(KERN_DEBUG "mppe_decompress[%d]: short pkt (%d)\n",
+ state->unit, isize);
+ return DECOMP_ERROR;
+ }
+ /* Strange ... our output size is always LESS than the input size. */
+ /* assert(osize >= isize - MPPE_OVHD - 2); */
+
+ osize = isize - MPPE_OVHD - 2;
+
+ ccount = MPPE_CCOUNT(ibuf);
+
+ /* sanity checks -- terminate with extreme prejudice */
+ if (!(MPPE_BITS(ibuf) & MPPE_BIT_ENCRYPTED)) {
+ printk(KERN_DEBUG "mppe_decompress[%d]: ENCRYPTED bit not set!\n",
+ state->unit);
+ state->sanity_errors += 100;
+ sanity = 1;
+ }
+ if (!state->stateful && !flushed) {
+ printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set in "
+ "stateless mode!\n", state->unit);
+ state->sanity_errors += 100;
+ sanity = 1;
+ }
+ if (state->stateful && ((ccount & 0xff) == 0xff) && !flushed) {
+ printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set on "
+ "flag packet!\n", state->unit);
+ state->sanity_errors += 100;
+ sanity = 1;
+ }
+
+ if (sanity) {
+ if (state->sanity_errors < SANITY_MAX)
+ return DECOMP_ERROR;
+ else
+ /*
+ * Take LCP down if the peer is sending too many bogons.
+ * We don't want to do this for a single or just a few
+ * instances since it could just be due to packet corruption.
+ */
+ return DECOMP_FATALERROR;
+ }
+
+ /*
+ * Check the coherency count.
+ */
+
+ if (!state->stateful) {
+ /* RFC 3078, sec 8.1. Rekey for every packet. */
+ while (state->ccount != ccount) {
+ mppe_rekey(state, 0);
+ state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
+ }
+ } else {
+ /* RFC 3078, sec 8.2. */
+ if (!state->discard) {
+ /* normal state */
+ state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
+ if (ccount != state->ccount) {
+ /*
+ * (ccount > state->ccount)
+ * Packet loss detected, enter the discard state.
+ * Signal the peer to rekey (by sending a CCP Reset-Request).
+ */
+ state->discard = 1;
+ return DECOMP_ERROR;
+ }
+ } else {
+ /* discard state */
+ if (!flushed) {
+ /* ccp.c will be silent (no additional CCP Reset-Requests). */
+ return DECOMP_ERROR;
+ } else {
+ /* Rekey for every missed "flag" packet. */
+ while ((ccount & ~0xff) != (state->ccount & ~0xff)) {
+ mppe_rekey(state, 0);
+ state->ccount = (state->ccount + 256) % MPPE_CCOUNT_SPACE;
+ }
+
+ /* reset */
+ state->discard = 0;
+ state->ccount = ccount;
+ /*
+ * Another problem with RFC 3078 here. It implies that the
+ * peer need not send a Reset-Ack packet. But RFC 1962
+ * requires it. Hopefully, M$ does send a Reset-Ack; even
+ * though it isn't required for MPPE synchronization, it is
+ * required to reset CCP state.
+ */
+ }
+ }
+ if (flushed)
+ mppe_rekey(state, 0);
+ }
+
+ /*
+ * Fill in the first part of the PPP header. The protocol field
+ * comes from the decrypted data.
+ */
+ obuf[0] = PPP_ADDRESS(ibuf); /* +1 */
+ obuf[1] = PPP_CONTROL(ibuf); /* +2 */
+ obuf += 2;
+ ibuf += PPP_HDRLEN + MPPE_OVHD;
+ isize -= PPP_HDRLEN + MPPE_OVHD; /* -6 */
+ /* net: -4 */
+
+ /* And finally, decrypt the packet. */
+ arcfour_decrypt(&state->arcfour_context, ibuf, isize, obuf);
+
+ state->stats.unc_bytes += osize;
+ state->stats.unc_packets++;
+ state->stats.comp_bytes += isize;
+ state->stats.comp_packets++;
+
+ /* good packet credit */
+ state->sanity_errors >>= 1;
+
+ return osize;
+}
+
+/*
+ * Incompressible data has arrived (this should never happen!).
+ * We should probably drop the link if the protocol is in the range
+ * of what should be encrypted. At the least, we should drop this
+ * packet. (How to do this?)
+ */
+static void
+mppe_incomp(void *arg, unsigned char *ibuf, int icnt)
+{
+ ppp_mppe_state *state = (ppp_mppe_state *) arg;
+
+ if (state->debug &&
+ (PPP_PROTOCOL(ibuf) >= 0x0021 && PPP_PROTOCOL(ibuf) <= 0x00fa))
+ printk(KERN_DEBUG "mppe_incomp[%d]: incompressible (unencrypted) data! "
+ "(proto %04x)\n", state->unit, PPP_PROTOCOL(ibuf));
+
+ state->stats.inc_bytes += icnt;
+ state->stats.inc_packets++;
+ state->stats.unc_bytes += icnt;
+ state->stats.unc_packets++;
+}
+
+/*************************************************************
+ * Module interface table
+ *************************************************************/
+
+/* These are in ppp.c */
+extern int ppp_register_compressor (struct compressor *cp);
+extern void ppp_unregister_compressor (struct compressor *cp);
+
+/*
+ * Procedures exported to if_ppp.c.
+ */
+struct compressor ppp_mppe = {
+ CI_MPPE, /* compress_proto */
+ mppe_alloc, /* comp_alloc */
+ mppe_free, /* comp_free */
+ mppe_comp_init, /* comp_init */
+ mppe_comp_reset, /* comp_reset */
+ mppe_compress, /* compress */
+ mppe_comp_stats, /* comp_stat */
+ mppe_alloc, /* decomp_alloc */
+ mppe_free, /* decomp_free */
+ mppe_decomp_init, /* decomp_init */
+ mppe_decomp_reset, /* decomp_reset */
+ mppe_decompress, /* decompress */
+ mppe_incomp, /* incomp */
+ mppe_comp_stats, /* decomp_stat */
+};
+
+__initfunc(int ppp_mppe_install(void))
+{
+ int answer = ppp_register_compressor(&ppp_mppe);
+
+ if (answer == 0)
+ printk(KERN_INFO "PPP MPPE Compression module registered\n");
+ return answer;
+}
+
+#ifdef MODULE
+
+int
+init_module(void)
+{
+ return ppp_mppe_install();
+}
+
+void
+cleanup_module(void)
+{
+ if (MOD_IN_USE)
+ printk(KERN_INFO "PPP MPPE Compression module busy\n");
+ else
+ ppp_unregister_compressor(&ppp_mppe);
+}
+#endif
--- /dev/null
+/*
+ * ftp://ftp.funet.fi/pub/crypt/hash/sha/sha1.c
+ *
+ * SHA-1 in C
+ * By Steve Reid <steve@edmweb.com>
+ * 100% Public Domain
+ *
+ * Test Vectors (from FIPS PUB 180-1)
+ * "abc"
+ * A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
+ * "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
+ * 84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1
+ * A million repetitions of "a"
+ * 34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
+ */
+
+/* #define SHA1HANDSOFF * Copies data before messing with it. */
+
+#if defined(__linux__)
+#include <asm/byteorder.h>
+#include <linux/string.h>
+#else if defined(__solaris__)
+#include <sys/isa_defs.h>
+#include <sys/ddi.h>
+#include <sys/sunddi.h>
+#define memcpy(d, s, c) bcopy(s, d, c)
+#define memset(d, b, c) bzero(d, c)
+#endif
+
+#include "sha1.h"
+
+static void SHA1_Transform(unsigned long[5], const unsigned char[64]);
+
+#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
+
+/* blk0() and blk() perform the initial expand. */
+/* I got the idea of expanding during the round function from SSLeay */
+#if defined(__LITTLE_ENDIAN) || defined(_LITTLE_ENDIAN)
+#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
+ |(rol(block->l[i],8)&0x00FF00FF))
+#elif defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN)
+#define blk0(i) block->l[i]
+#else
+#error Endianness not defined
+#endif
+#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
+ ^block->l[(i+2)&15]^block->l[i&15],1))
+
+/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
+#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
+#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
+#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
+#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
+#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
+
+
+/* Hash a single 512-bit block. This is the core of the algorithm. */
+
+static void
+SHA1_Transform(unsigned long state[5], const unsigned char buffer[64])
+{
+ unsigned long a, b, c, d, e;
+ typedef union {
+ unsigned char c[64];
+ unsigned long l[16];
+ } CHAR64LONG16;
+ CHAR64LONG16 *block;
+
+#ifdef SHA1HANDSOFF
+ static unsigned char workspace[64];
+ block = (CHAR64LONG16 *) workspace;
+ memcpy(block, buffer, 64);
+#else
+ block = (CHAR64LONG16 *) buffer;
+#endif
+ /* Copy context->state[] to working vars */
+ a = state[0];
+ b = state[1];
+ c = state[2];
+ d = state[3];
+ e = state[4];
+ /* 4 rounds of 20 operations each. Loop unrolled. */
+ R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
+ R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
+ R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
+ R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
+ R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
+ R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
+ R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
+ R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
+ R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
+ R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
+ R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
+ R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
+ R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
+ R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
+ R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
+ R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
+ R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
+ R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
+ R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
+ R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
+ /* Add the working vars back into context.state[] */
+ state[0] += a;
+ state[1] += b;
+ state[2] += c;
+ state[3] += d;
+ state[4] += e;
+ /* Wipe variables */
+ a = b = c = d = e = 0;
+}
+
+
+/* SHA1Init - Initialize new context */
+
+void
+SHA1_Init(SHA1_CTX *context)
+{
+ /* SHA1 initialization constants */
+ context->state[0] = 0x67452301;
+ context->state[1] = 0xEFCDAB89;
+ context->state[2] = 0x98BADCFE;
+ context->state[3] = 0x10325476;
+ context->state[4] = 0xC3D2E1F0;
+ context->count[0] = context->count[1] = 0;
+}
+
+
+/* Run your data through this. */
+
+void
+SHA1_Update(SHA1_CTX *context, const unsigned char *data, unsigned int len)
+{
+ unsigned int i, j;
+
+ j = (context->count[0] >> 3) & 63;
+ if ((context->count[0] += len << 3) < (len << 3)) context->count[1]++;
+ context->count[1] += (len >> 29);
+ if ((j + len) > 63) {
+ memcpy(&context->buffer[j], data, (i = 64-j));
+ SHA1_Transform(context->state, context->buffer);
+ for ( ; i + 63 < len; i += 64) {
+ SHA1_Transform(context->state, &data[i]);
+ }
+ j = 0;
+ }
+ else
+ i = 0;
+
+ memcpy(&context->buffer[j], &data[i], len - i);
+}
+
+
+/* Add padding and return the message digest. */
+
+void
+SHA1_Final(unsigned char digest[20], SHA1_CTX *context)
+{
+ unsigned long i, j;
+ unsigned char finalcount[8];
+
+ for (i = 0; i < 8; i++) {
+ finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
+ >> ((3-(i & 3)) * 8) ) & 255); /* Endian independent */
+ }
+ SHA1_Update(context, (unsigned char *) "\200", 1);
+ while ((context->count[0] & 504) != 448) {
+ SHA1_Update(context, (unsigned char *) "\0", 1);
+ }
+ SHA1_Update(context, finalcount, 8); /* Should cause a SHA1Transform() */
+ for (i = 0; i < 20; i++) {
+ digest[i] = (unsigned char)
+ ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
+ }
+ /* Wipe variables */
+ i = j = 0;
+ memset(context->buffer, 0, 64);
+ memset(context->state, 0, 20);
+ memset(context->count, 0, 8);
+ memset(&finalcount, 0, 8);
+#ifdef SHA1HANDSOFF /* make SHA1Transform overwrite it's own static vars */
+ SHA1Transform(context->state, context->buffer);
+#endif
+}
+
--- /dev/null
+/* sha1.h */
+
+#ifndef _SHA1_H
+#define _SHA1_H
+
+typedef struct {
+ unsigned long state[5];
+ unsigned long count[2];
+ unsigned char buffer[64];
+} SHA1_CTX;
+
+#define SHA1_SIGNATURE_SIZE 20
+
+extern void SHA1_Init(SHA1_CTX *);
+extern void SHA1_Update(SHA1_CTX *, const unsigned char *, unsigned int);
+extern void SHA1_Final(unsigned char[SHA1_SIGNATURE_SIZE], SHA1_CTX *);
+
+#endif /* _SHA1_H */
projects / ppp.git / commitdiff