From: David F. Skoll Date: Tue, 2 Apr 2002 14:01:37 +0000 (+0000) Subject: Added kernel MPPE patches (2.2.20 kernel only!) from Frank Cusack. X-Git-Tag: ppp-2.4.7~425 X-Git-Url: http://git.ozlabs.org/?p=ppp.git;a=commitdiff_plain;h=dbab7400abf57617a9334735a64ff00c6552cec5;hp=67ccbff7ff8402cce48d15994713c196f683a280 Added kernel MPPE patches (2.2.20 kernel only!) from Frank Cusack. --- diff --git a/linux/mppe/arcfour.c b/linux/mppe/arcfour.c new file mode 100644 index 0000000..35b3f42 --- /dev/null +++ b/linux/mppe/arcfour.c @@ -0,0 +1,72 @@ +/* + * arcfour.c + * by Frank Cusack + * 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 . + */ + +#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; +} + diff --git a/linux/mppe/arcfour.h b/linux/mppe/arcfour.h new file mode 100644 index 0000000..27abefb --- /dev/null +++ b/linux/mppe/arcfour.h @@ -0,0 +1,17 @@ +/* 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 */ diff --git a/linux/mppe/linux-2.2.20-include.patch b/linux/mppe/linux-2.2.20-include.patch new file mode 100644 index 0000000..e248834 --- /dev/null +++ b/linux/mppe/linux-2.2.20-include.patch @@ -0,0 +1,103 @@ +--- 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. + */ + diff --git a/linux/mppe/linux-2.2.20-make.patch b/linux/mppe/linux-2.2.20-make.patch new file mode 100644 index 0000000..b0a936e --- /dev/null +++ b/linux/mppe/linux-2.2.20-make.patch @@ -0,0 +1,43 @@ +--- 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 diff --git a/linux/mppe/linux-2.2.20-pad.patch b/linux/mppe/linux-2.2.20-pad.patch new file mode 100644 index 0000000..a0b714a --- /dev/null +++ b/linux/mppe/linux-2.2.20-pad.patch @@ -0,0 +1,45 @@ +--- 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; + } + } + diff --git a/linux/mppe/modutils-2.3.21-mppe.patch b/linux/mppe/modutils-2.3.21-mppe.patch new file mode 100644 index 0000000..3135757 --- /dev/null +++ b/linux/mppe/modutils-2.3.21-mppe.patch @@ -0,0 +1,10 @@ +--- 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", diff --git a/linux/mppe/mppeinstall.sh b/linux/mppe/mppeinstall.sh new file mode 100644 index 0000000..f2f1740 --- /dev/null +++ b/linux/mppe/mppeinstall.sh @@ -0,0 +1,28 @@ +#!/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 diff --git a/linux/mppe/ppp_mppe_compress.c b/linux/mppe/ppp_mppe_compress.c new file mode 100644 index 0000000..8b62ba7 --- /dev/null +++ b/linux/mppe/ppp_mppe_compress.c @@ -0,0 +1,611 @@ +/* + * ==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 . + * 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 +#include +#include +#include +#include +#include + +#include +#include + +#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 diff --git a/linux/mppe/sha1.c b/linux/mppe/sha1.c new file mode 100644 index 0000000..79ef20d --- /dev/null +++ b/linux/mppe/sha1.c @@ -0,0 +1,185 @@ +/* + * ftp://ftp.funet.fi/pub/crypt/hash/sha/sha1.c + * + * SHA-1 in C + * By Steve Reid + * 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 +#include +#else if defined(__solaris__) +#include +#include +#include +#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 +} + diff --git a/linux/mppe/sha1.h b/linux/mppe/sha1.h new file mode 100644 index 0000000..b23356b --- /dev/null +++ b/linux/mppe/sha1.h @@ -0,0 +1,18 @@ +/* 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 */