Added kernel MPPE patches (2.2.20 kernel only!) from Frank Cusack.
authorDavid F. Skoll <dfs@roaringpenguin.com>
Tue, 2 Apr 2002 14:01:37 +0000 (14:01 +0000)
committerDavid F. Skoll <dfs@roaringpenguin.com>
Tue, 2 Apr 2002 14:01:37 +0000 (14:01 +0000)
linux/mppe/arcfour.c [new file with mode: 0644]
linux/mppe/arcfour.h [new file with mode: 0644]
linux/mppe/linux-2.2.20-include.patch [new file with mode: 0644]
linux/mppe/linux-2.2.20-make.patch [new file with mode: 0644]
linux/mppe/linux-2.2.20-pad.patch [new file with mode: 0644]
linux/mppe/modutils-2.3.21-mppe.patch [new file with mode: 0644]
linux/mppe/mppeinstall.sh [new file with mode: 0644]
linux/mppe/ppp_mppe_compress.c [new file with mode: 0644]
linux/mppe/sha1.c [new file with mode: 0644]
linux/mppe/sha1.h [new file with mode: 0644]

diff --git a/linux/mppe/arcfour.c b/linux/mppe/arcfour.c
new file mode 100644 (file)
index 0000000..35b3f42
--- /dev/null
@@ -0,0 +1,72 @@
+/*
+ * 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;
+}
+
diff --git a/linux/mppe/arcfour.h b/linux/mppe/arcfour.h
new file mode 100644 (file)
index 0000000..27abefb
--- /dev/null
@@ -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 (file)
index 0000000..e248834
--- /dev/null
@@ -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 (file)
index 0000000..b0a936e
--- /dev/null
@@ -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 (file)
index 0000000..a0b714a
--- /dev/null
@@ -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 (file)
index 0000000..3135757
--- /dev/null
@@ -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 (file)
index 0000000..f2f1740
--- /dev/null
@@ -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 (file)
index 0000000..8b62ba7
--- /dev/null
@@ -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 <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
diff --git a/linux/mppe/sha1.c b/linux/mppe/sha1.c
new file mode 100644 (file)
index 0000000..79ef20d
--- /dev/null
@@ -0,0 +1,185 @@
+/*
+ * 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
+}
+
diff --git a/linux/mppe/sha1.h b/linux/mppe/sha1.h
new file mode 100644 (file)
index 0000000..b23356b
--- /dev/null
@@ -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 */