--- /dev/null
+/*
+ * ppp_mppe.c - interface MPPE to the PPP code.
+ * This version is for use with Linux kernel 2.6.14+
+ *
+ * By Frank Cusack <fcusack@fcusack.com>.
+ * Copyright (c) 2002,2003,2004 Google, Inc.
+ * All rights reserved.
+ *
+ * License:
+ * 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.
+ *
+ * ALTERNATIVELY, provided that this notice is retained in full, this product
+ * may be distributed under the terms of the GNU General Public License (GPL),
+ * in which case the provisions of the GPL apply INSTEAD OF those given above.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Changelog:
+ * 08/12/05 - Matt Domsch <Matt_Domsch@dell.com>
+ * Only need extra skb padding on transmit, not receive.
+ * 06/18/04 - Matt Domsch <Matt_Domsch@dell.com>, Oleg Makarenko <mole@quadra.ru>
+ * Use Linux kernel 2.6 arc4 and sha1 routines rather than
+ * providing our own.
+ * 2/15/04 - TS: added #include <version.h> and testing for Kernel
+ * version before using
+ * MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are
+ * deprecated in 2.6
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+#include <linux/mm.h>
+#include <linux/ppp_defs.h>
+#include <linux/ppp-comp.h>
+#include <linux/scatterlist.h>
+#include <asm/unaligned.h>
+
+#include "ppp_mppe.h"
+
+MODULE_AUTHOR("Frank Cusack <fcusack@fcusack.com>");
+MODULE_DESCRIPTION("Point-to-Point Protocol Microsoft Point-to-Point Encryption support");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("ppp-compress-" __stringify(CI_MPPE));
+MODULE_VERSION("1.0.2");
+
+static unsigned int
+setup_sg(struct scatterlist *sg, const void *address, unsigned int length)
+{
+ sg_set_buf(sg, address, length);
+ return length;
+}
+
+#define SHA1_PAD_SIZE 40
+
+/*
+ * kernel crypto API needs its arguments to be in kmalloc'd memory, not in the module
+ * static data area. That means sha_pad needs to be kmalloc'd.
+ */
+
+struct sha_pad {
+ unsigned char sha_pad1[SHA1_PAD_SIZE];
+ unsigned char sha_pad2[SHA1_PAD_SIZE];
+};
+static struct sha_pad *sha_pad;
+
+static inline void sha_pad_init(struct sha_pad *shapad)
+{
+ memset(shapad->sha_pad1, 0x00, sizeof(shapad->sha_pad1));
+ memset(shapad->sha_pad2, 0xF2, sizeof(shapad->sha_pad2));
+}
+
+/*
+ * State for an MPPE (de)compressor.
+ */
+struct ppp_mppe_state {
+ struct crypto_blkcipher *arc4;
+ struct crypto_hash *sha1;
+ unsigned char *sha1_digest;
+ unsigned char master_key[MPPE_MAX_KEY_LEN];
+ unsigned char session_key[MPPE_MAX_KEY_LEN];
+ 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;
+};
+
+/* struct 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 */
+
+#define MPPE_OVHD 2 /* MPPE overhead/packet */
+#define SANITY_MAX 1600 /* Max bogon factor we will tolerate */
+
+/*
+ * Key Derivation, from RFC 3078, RFC 3079.
+ * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
+ */
+static void get_new_key_from_sha(struct ppp_mppe_state * state)
+{
+ struct hash_desc desc;
+ struct scatterlist sg[4];
+ unsigned int nbytes;
+
+ sg_init_table(sg, 4);
+
+ nbytes = setup_sg(&sg[0], state->master_key, state->keylen);
+ nbytes += setup_sg(&sg[1], sha_pad->sha_pad1,
+ sizeof(sha_pad->sha_pad1));
+ nbytes += setup_sg(&sg[2], state->session_key, state->keylen);
+ nbytes += setup_sg(&sg[3], sha_pad->sha_pad2,
+ sizeof(sha_pad->sha_pad2));
+
+ desc.tfm = state->sha1;
+ desc.flags = 0;
+
+ crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
+}
+
+/*
+ * 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(struct ppp_mppe_state * state, int initial_key)
+{
+ struct scatterlist sg_in[1], sg_out[1];
+ struct blkcipher_desc desc = { .tfm = state->arc4 };
+
+ get_new_key_from_sha(state);
+ if (!initial_key) {
+ crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
+ state->keylen);
+ sg_init_table(sg_in, 1);
+ sg_init_table(sg_out, 1);
+ setup_sg(sg_in, state->sha1_digest, state->keylen);
+ setup_sg(sg_out, state->session_key, state->keylen);
+ if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
+ state->keylen) != 0) {
+ printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
+ }
+ } else {
+ memcpy(state->session_key, state->sha1_digest, state->keylen);
+ }
+ if (state->keylen == 8) {
+ /* See RFC 3078 */
+ state->session_key[0] = 0xd1;
+ state->session_key[1] = 0x26;
+ state->session_key[2] = 0x9e;
+ }
+ crypto_blkcipher_setkey(state->arc4, state->session_key, state->keylen);
+}
+
+/*
+ * Allocate space for a (de)compressor.
+ */
+static void *mppe_alloc(unsigned char *options, int optlen)
+{
+ struct ppp_mppe_state *state;
+ unsigned int digestsize;
+
+ if (optlen != CILEN_MPPE + sizeof(state->master_key) ||
+ options[0] != CI_MPPE || options[1] != CILEN_MPPE)
+ goto out;
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (state == NULL)
+ goto out;
+
+
+ state->arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(state->arc4)) {
+ state->arc4 = NULL;
+ goto out_free;
+ }
+
+ state->sha1 = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(state->sha1)) {
+ state->sha1 = NULL;
+ goto out_free;
+ }
+
+ digestsize = crypto_hash_digestsize(state->sha1);
+ if (digestsize < MPPE_MAX_KEY_LEN)
+ goto out_free;
+
+ state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
+ if (!state->sha1_digest)
+ goto out_free;
+
+ /* 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;
+
+ out_free:
+ if (state->sha1_digest)
+ kfree(state->sha1_digest);
+ if (state->sha1)
+ crypto_free_hash(state->sha1);
+ if (state->arc4)
+ crypto_free_blkcipher(state->arc4);
+ kfree(state);
+ out:
+ return NULL;
+}
+
+/*
+ * Deallocate space for a (de)compressor.
+ */
+static void mppe_free(void *arg)
+{
+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
+ if (state) {
+ if (state->sha1_digest)
+ kfree(state->sha1_digest);
+ if (state->sha1)
+ crypto_free_hash(state->sha1);
+ if (state->arc4)
+ crypto_free_blkcipher(state->arc4);
+ kfree(state);
+ }
+}
+
+/*
+ * Initialize (de)compressor state.
+ */
+static int
+mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug,
+ const char *debugstr)
+{
+ struct ppp_mppe_state *state = (struct 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) * 2 + 1];
+ char skey[sizeof(state->session_key) * 2 + 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, "%02x", state->master_key[i]);
+ for (i = 0; i < sizeof(state->session_key); i++)
+ sprintf(skey + i * 2, "%02x", 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)
+{
+ struct ppp_mppe_state *state = (struct 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.
+ */
+static int
+mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
+ int isize, int osize)
+{
+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
+ struct blkcipher_desc desc = { .tfm = state->arc4 };
+ int proto;
+ struct scatterlist sg_in[1], sg_out[1];
+
+ /*
+ * 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);
+ put_unaligned_be16(PPP_COMP, obuf + 2);
+ obuf += PPP_HDRLEN;
+
+ state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
+ if (state->debug >= 7)
+ printk(KERN_DEBUG "mppe_compress[%d]: ccount %d\n", state->unit,
+ state->ccount);
+ put_unaligned_be16(state->ccount, obuf);
+
+ 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 */
+ sg_init_table(sg_in, 1);
+ sg_init_table(sg_out, 1);
+ setup_sg(sg_in, ibuf, isize);
+ setup_sg(sg_out, obuf, osize);
+ if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in, isize) != 0) {
+ printk(KERN_DEBUG "crypto_cypher_encrypt failed\n");
+ return -1;
+ }
+
+ 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)
+{
+ struct ppp_mppe_state *state = (struct 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.
+ */
+static int
+mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf,
+ int osize)
+{
+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
+ struct blkcipher_desc desc = { .tfm = state->arc4 };
+ unsigned ccount;
+ int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED;
+ struct scatterlist sg_in[1], sg_out[1];
+
+ 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;
+ }
+
+ /*
+ * Make sure we have enough room to decrypt the packet.
+ * Note that for our test we only subtract 1 byte whereas in
+ * mppe_compress() we added 2 bytes (+MPPE_OVHD);
+ * this is to account for possible PFC.
+ */
+ if (osize < isize - MPPE_OVHD - 1) {
+ printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! "
+ "(have: %d need: %d)\n", state->unit,
+ osize, isize - MPPE_OVHD - 1);
+ return DECOMP_ERROR;
+ }
+ osize = isize - MPPE_OVHD - 2; /* assume no PFC */
+
+ ccount = MPPE_CCOUNT(ibuf);
+ if (state->debug >= 7)
+ printk(KERN_DEBUG "mppe_decompress[%d]: ccount %d\n",
+ state->unit, ccount);
+
+ /* 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;
+ goto sanity_error;
+ }
+ if (!state->stateful && !flushed) {
+ printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set in "
+ "stateless mode!\n", state->unit);
+ state->sanity_errors += 100;
+ goto sanity_error;
+ }
+ 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;
+ goto sanity_error;
+ }
+
+ /*
+ * Check the coherency count.
+ */
+
+ if (!state->stateful) {
+ /* Discard late packet */
+ if ((ccount - state->ccount) % MPPE_CCOUNT_SPACE
+ > MPPE_CCOUNT_SPACE / 2) {
+ state->sanity_errors++;
+ goto sanity_error;
+ }
+
+ /* 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); /* +1 */
+ obuf += 2;
+ ibuf += PPP_HDRLEN + MPPE_OVHD;
+ isize -= PPP_HDRLEN + MPPE_OVHD; /* -6 */
+ /* net osize: isize-4 */
+
+ /*
+ * Decrypt the first byte in order to check if it is
+ * a compressed or uncompressed protocol field.
+ */
+ sg_init_table(sg_in, 1);
+ sg_init_table(sg_out, 1);
+ setup_sg(sg_in, ibuf, 1);
+ setup_sg(sg_out, obuf, 1);
+ if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, 1) != 0) {
+ printk(KERN_DEBUG "crypto_cypher_decrypt failed\n");
+ return DECOMP_ERROR;
+ }
+
+ /*
+ * Do PFC decompression.
+ * This would be nicer if we were given the actual sk_buff
+ * instead of a char *.
+ */
+ if ((obuf[0] & 0x01) != 0) {
+ obuf[1] = obuf[0];
+ obuf[0] = 0;
+ obuf++;
+ osize++;
+ }
+
+ /* And finally, decrypt the rest of the packet. */
+ setup_sg(sg_in, ibuf + 1, isize - 1);
+ setup_sg(sg_out, obuf + 1, osize - 1);
+ if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, isize - 1)) {
+ printk(KERN_DEBUG "crypto_cypher_decrypt failed\n");
+ return DECOMP_ERROR;
+ }
+
+ 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;
+
+sanity_error:
+ 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;
+}
+
+/*
+ * 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)
+{
+ struct ppp_mppe_state *state = (struct 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
+ *************************************************************/
+
+/*
+ * Procedures exported to if_ppp.c.
+ */
+static struct compressor ppp_mppe = {
+ .compress_proto = CI_MPPE,
+ .comp_alloc = mppe_alloc,
+ .comp_free = mppe_free,
+ .comp_init = mppe_comp_init,
+ .comp_reset = mppe_comp_reset,
+ .compress = mppe_compress,
+ .comp_stat = mppe_comp_stats,
+ .decomp_alloc = mppe_alloc,
+ .decomp_free = mppe_free,
+ .decomp_init = mppe_decomp_init,
+ .decomp_reset = mppe_decomp_reset,
+ .decompress = mppe_decompress,
+ .incomp = mppe_incomp,
+ .decomp_stat = mppe_comp_stats,
+ .owner = THIS_MODULE,
+ .comp_extra = MPPE_PAD,
+};
+
+/*
+ * ppp_mppe_init()
+ *
+ * Prior to allowing load, try to load the arc4 and sha1 crypto
+ * libraries. The actual use will be allocated later, but
+ * this way the module will fail to insmod if they aren't available.
+ */
+
+static int __init ppp_mppe_init(void)
+{
+ int answer;
+ if (!(crypto_has_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC) &&
+ crypto_has_hash("sha1", 0, CRYPTO_ALG_ASYNC)))
+ return -ENODEV;
+
+ sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL);
+ if (!sha_pad)
+ return -ENOMEM;
+ sha_pad_init(sha_pad);
+
+ answer = ppp_register_compressor(&ppp_mppe);
+
+ if (answer == 0)
+ printk(KERN_INFO "PPP MPPE Compression module registered\n");
+ else
+ kfree(sha_pad);
+
+ return answer;
+}
+
+static void __exit ppp_mppe_cleanup(void)
+{
+ ppp_unregister_compressor(&ppp_mppe);
+ kfree(sha_pad);
+}
+
+module_init(ppp_mppe_init);
+module_exit(ppp_mppe_cleanup);
Code Review / kvmfornfv.git / blobdiff