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@@ -0,0 +1,724 @@
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+/*
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+ * ppp_mppe.c - interface MPPE to the PPP code.
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+ * This version is for use with Linux kernel 2.6.14+
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+ *
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+ * By Frank Cusack <fcusack@fcusack.com>.
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+ * Copyright (c) 2002,2003,2004 Google, Inc.
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+ * All rights reserved.
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+ *
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+ * License:
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+ * Permission to use, copy, modify, and distribute this software and its
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+ * documentation is hereby granted, provided that the above copyright
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+ * notice appears in all copies. This software is provided without any
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+ * warranty, express or implied.
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+ *
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+ * ALTERNATIVELY, provided that this notice is retained in full, this product
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+ * may be distributed under the terms of the GNU General Public License (GPL),
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+ * in which case the provisions of the GPL apply INSTEAD OF those given above.
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2 of the License, or
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+ * (at your option) any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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+ *
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+ *
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+ * Changelog:
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+ * 08/12/05 - Matt Domsch <Matt_Domsch@dell.com>
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+ * Only need extra skb padding on transmit, not receive.
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+ * 06/18/04 - Matt Domsch <Matt_Domsch@dell.com>, Oleg Makarenko <mole@quadra.ru>
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+ * Use Linux kernel 2.6 arc4 and sha1 routines rather than
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+ * providing our own.
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+ * 2/15/04 - TS: added #include <version.h> and testing for Kernel
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+ * version before using
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+ * MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are
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+ * deprecated in 2.6
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+ */
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+
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+#include <linux/config.h>
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+#include <linux/module.h>
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+#include <linux/kernel.h>
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+#include <linux/version.h>
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+#include <linux/init.h>
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+#include <linux/types.h>
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+#include <linux/slab.h>
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+#include <linux/string.h>
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+#include <linux/crypto.h>
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+#include <linux/mm.h>
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+#include <linux/ppp_defs.h>
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+#include <linux/ppp-comp.h>
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+#include <asm/scatterlist.h>
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+
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+#include "ppp_mppe.h"
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+
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+MODULE_AUTHOR("Frank Cusack <fcusack@fcusack.com>");
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+MODULE_DESCRIPTION("Point-to-Point Protocol Microsoft Point-to-Point Encryption support");
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+MODULE_LICENSE("Dual BSD/GPL");
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+MODULE_ALIAS("ppp-compress-" __stringify(CI_MPPE));
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+MODULE_VERSION("1.0.2");
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+
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+static void
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+setup_sg(struct scatterlist *sg, const void *address, unsigned int length)
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+{
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+ sg[0].page = virt_to_page(address);
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+ sg[0].offset = offset_in_page(address);
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+ sg[0].length = length;
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+}
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+
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+#define SHA1_PAD_SIZE 40
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+
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+/*
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+ * kernel crypto API needs its arguments to be in kmalloc'd memory, not in the module
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+ * static data area. That means sha_pad needs to be kmalloc'd.
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+ */
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+
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+struct sha_pad {
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+ unsigned char sha_pad1[SHA1_PAD_SIZE];
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+ unsigned char sha_pad2[SHA1_PAD_SIZE];
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+};
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+static struct sha_pad *sha_pad;
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+
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+static inline void sha_pad_init(struct sha_pad *shapad)
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+{
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+ memset(shapad->sha_pad1, 0x00, sizeof(shapad->sha_pad1));
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+ memset(shapad->sha_pad2, 0xF2, sizeof(shapad->sha_pad2));
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+}
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+
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+/*
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+ * State for an MPPE (de)compressor.
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+ */
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+struct ppp_mppe_state {
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+ struct crypto_tfm *arc4;
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+ struct crypto_tfm *sha1;
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+ unsigned char *sha1_digest;
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+ unsigned char master_key[MPPE_MAX_KEY_LEN];
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+ unsigned char session_key[MPPE_MAX_KEY_LEN];
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+ unsigned keylen; /* key length in bytes */
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+ /* NB: 128-bit == 16, 40-bit == 8! */
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+ /* If we want to support 56-bit, */
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+ /* the unit has to change to bits */
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+ unsigned char bits; /* MPPE control bits */
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+ unsigned ccount; /* 12-bit coherency count (seqno) */
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+ unsigned stateful; /* stateful mode flag */
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+ int discard; /* stateful mode packet loss flag */
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+ int sanity_errors; /* take down LCP if too many */
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+ int unit;
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+ int debug;
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+ struct compstat stats;
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+};
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+
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+/* struct ppp_mppe_state.bits definitions */
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+#define MPPE_BIT_A 0x80 /* Encryption table were (re)inititalized */
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+#define MPPE_BIT_B 0x40 /* MPPC only (not implemented) */
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+#define MPPE_BIT_C 0x20 /* MPPC only (not implemented) */
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+#define MPPE_BIT_D 0x10 /* This is an encrypted frame */
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+
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+#define MPPE_BIT_FLUSHED MPPE_BIT_A
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+#define MPPE_BIT_ENCRYPTED MPPE_BIT_D
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+
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+#define MPPE_BITS(p) ((p)[4] & 0xf0)
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+#define MPPE_CCOUNT(p) ((((p)[4] & 0x0f) << 8) + (p)[5])
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+#define MPPE_CCOUNT_SPACE 0x1000 /* The size of the ccount space */
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+
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+#define MPPE_OVHD 2 /* MPPE overhead/packet */
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+#define SANITY_MAX 1600 /* Max bogon factor we will tolerate */
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+
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+/*
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+ * Key Derivation, from RFC 3078, RFC 3079.
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+ * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
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+ */
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+static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *InterimKey)
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+{
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+ struct scatterlist sg[4];
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+
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+ setup_sg(&sg[0], state->master_key, state->keylen);
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+ setup_sg(&sg[1], sha_pad->sha_pad1, sizeof(sha_pad->sha_pad1));
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+ setup_sg(&sg[2], state->session_key, state->keylen);
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+ setup_sg(&sg[3], sha_pad->sha_pad2, sizeof(sha_pad->sha_pad2));
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+
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+ crypto_digest_digest (state->sha1, sg, 4, state->sha1_digest);
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+
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+ memcpy(InterimKey, state->sha1_digest, state->keylen);
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+}
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+
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+/*
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+ * Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3.
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+ * Well, not what's written there, but rather what they meant.
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+ */
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+static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
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+{
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+ unsigned char InterimKey[MPPE_MAX_KEY_LEN];
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+ struct scatterlist sg_in[1], sg_out[1];
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+
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+ get_new_key_from_sha(state, InterimKey);
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+ if (!initial_key) {
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+ crypto_cipher_setkey(state->arc4, InterimKey, state->keylen);
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+ setup_sg(sg_in, InterimKey, state->keylen);
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+ setup_sg(sg_out, state->session_key, state->keylen);
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+ if (crypto_cipher_encrypt(state->arc4, sg_out, sg_in,
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+ state->keylen) != 0) {
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+ printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
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+ }
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+ } else {
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+ memcpy(state->session_key, InterimKey, state->keylen);
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+ }
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+ if (state->keylen == 8) {
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+ /* See RFC 3078 */
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+ state->session_key[0] = 0xd1;
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+ state->session_key[1] = 0x26;
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+ state->session_key[2] = 0x9e;
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+ }
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+ crypto_cipher_setkey(state->arc4, state->session_key, state->keylen);
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+}
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+
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+/*
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+ * Allocate space for a (de)compressor.
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+ */
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+static void *mppe_alloc(unsigned char *options, int optlen)
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+{
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+ struct ppp_mppe_state *state;
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+ unsigned int digestsize;
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+
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+ if (optlen != CILEN_MPPE + sizeof(state->master_key)
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+ || options[0] != CI_MPPE || options[1] != CILEN_MPPE)
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+ goto out;
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+
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+ state = (struct ppp_mppe_state *) kmalloc(sizeof(*state), GFP_KERNEL);
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+ if (state == NULL)
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+ goto out;
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+
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+ memset(state, 0, sizeof(*state));
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+
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+ state->arc4 = crypto_alloc_tfm("arc4", 0);
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+ if (!state->arc4)
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+ goto out_free;
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+
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+ state->sha1 = crypto_alloc_tfm("sha1", 0);
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+ if (!state->sha1)
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+ goto out_free;
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+
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+ digestsize = crypto_tfm_alg_digestsize(state->sha1);
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+ if (digestsize < MPPE_MAX_KEY_LEN)
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+ goto out_free;
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+
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+ state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
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+ if (!state->sha1_digest)
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+ goto out_free;
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+
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+ /* Save keys. */
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+ memcpy(state->master_key, &options[CILEN_MPPE],
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+ sizeof(state->master_key));
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+ memcpy(state->session_key, state->master_key,
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+ sizeof(state->master_key));
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+
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+ /*
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+ * We defer initial key generation until mppe_init(), as mppe_alloc()
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+ * is called frequently during negotiation.
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+ */
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+
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+ return (void *)state;
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+
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+ out_free:
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+ if (state->sha1_digest)
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+ kfree(state->sha1_digest);
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+ if (state->sha1)
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+ crypto_free_tfm(state->sha1);
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+ if (state->arc4)
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+ crypto_free_tfm(state->arc4);
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+ kfree(state);
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+ out:
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+ return NULL;
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+}
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+
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+/*
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+ * Deallocate space for a (de)compressor.
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+ */
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+static void mppe_free(void *arg)
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+{
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+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
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+ if (state) {
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+ if (state->sha1_digest)
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+ kfree(state->sha1_digest);
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+ if (state->sha1)
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+ crypto_free_tfm(state->sha1);
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+ if (state->arc4)
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+ crypto_free_tfm(state->arc4);
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+ kfree(state);
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+ }
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+}
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+
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+/*
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+ * Initialize (de)compressor state.
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+ */
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+static int
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+mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug,
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+ const char *debugstr)
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+{
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+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
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+ unsigned char mppe_opts;
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+
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+ if (optlen != CILEN_MPPE
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+ || options[0] != CI_MPPE || options[1] != CILEN_MPPE)
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+ return 0;
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+
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+ MPPE_CI_TO_OPTS(&options[2], mppe_opts);
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+ if (mppe_opts & MPPE_OPT_128)
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+ state->keylen = 16;
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+ else if (mppe_opts & MPPE_OPT_40)
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+ state->keylen = 8;
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+ else {
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+ printk(KERN_WARNING "%s[%d]: unknown key length\n", debugstr,
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+ unit);
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+ return 0;
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+ }
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+ if (mppe_opts & MPPE_OPT_STATEFUL)
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+ state->stateful = 1;
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+
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+ /* Generate the initial session key. */
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+ mppe_rekey(state, 1);
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+
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+ if (debug) {
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+ int i;
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+ char mkey[sizeof(state->master_key) * 2 + 1];
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+ char skey[sizeof(state->session_key) * 2 + 1];
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+
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+ printk(KERN_DEBUG "%s[%d]: initialized with %d-bit %s mode\n",
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+ debugstr, unit, (state->keylen == 16) ? 128 : 40,
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+ (state->stateful) ? "stateful" : "stateless");
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+
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+ for (i = 0; i < sizeof(state->master_key); i++)
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+ sprintf(mkey + i * 2, "%02x", state->master_key[i]);
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+ for (i = 0; i < sizeof(state->session_key); i++)
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+ sprintf(skey + i * 2, "%02x", state->session_key[i]);
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+ printk(KERN_DEBUG
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+ "%s[%d]: keys: master: %s initial session: %s\n",
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+ debugstr, unit, mkey, skey);
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+ }
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+
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+ /*
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+ * Initialize the coherency count. The initial value is not specified
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+ * in RFC 3078, but we can make a reasonable assumption that it will
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+ * start at 0. Setting it to the max here makes the comp/decomp code
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+ * do the right thing (determined through experiment).
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+ */
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+ state->ccount = MPPE_CCOUNT_SPACE - 1;
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+
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+ /*
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+ * Note that even though we have initialized the key table, we don't
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+ * set the FLUSHED bit. This is contrary to RFC 3078, sec. 3.1.
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+ */
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+ state->bits = MPPE_BIT_ENCRYPTED;
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+
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+ state->unit = unit;
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+ state->debug = debug;
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+
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+ return 1;
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+}
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+
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+static int
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+mppe_comp_init(void *arg, unsigned char *options, int optlen, int unit,
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+ int hdrlen, int debug)
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+{
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+ /* ARGSUSED */
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+ return mppe_init(arg, options, optlen, unit, debug, "mppe_comp_init");
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+}
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+
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+/*
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+ * We received a CCP Reset-Request (actually, we are sending a Reset-Ack),
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+ * tell the compressor to rekey. Note that we MUST NOT rekey for
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+ * every CCP Reset-Request; we only rekey on the next xmit packet.
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+ * We might get multiple CCP Reset-Requests if our CCP Reset-Ack is lost.
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+ * So, rekeying for every CCP Reset-Request is broken as the peer will not
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+ * know how many times we've rekeyed. (If we rekey and THEN get another
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+ * CCP Reset-Request, we must rekey again.)
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+ */
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+static void mppe_comp_reset(void *arg)
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+{
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+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
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+
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+ state->bits |= MPPE_BIT_FLUSHED;
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+}
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+
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+/*
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+ * Compress (encrypt) a packet.
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+ * It's strange to call this a compressor, since the output is always
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+ * MPPE_OVHD + 2 bytes larger than the input.
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+ */
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+static int
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+mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
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+ int isize, int osize)
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+{
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+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
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+ int proto;
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+ struct scatterlist sg_in[1], sg_out[1];
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+
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+ /*
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+ * Check that the protocol is in the range we handle.
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+ */
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+ proto = PPP_PROTOCOL(ibuf);
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+ if (proto < 0x0021 || proto > 0x00fa)
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+ return 0;
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+
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+ /* Make sure we have enough room to generate an encrypted packet. */
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+ if (osize < isize + MPPE_OVHD + 2) {
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+ /* Drop the packet if we should encrypt it, but can't. */
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+ printk(KERN_DEBUG "mppe_compress[%d]: osize too small! "
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+ "(have: %d need: %d)\n", state->unit,
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+ osize, osize + MPPE_OVHD + 2);
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+ return -1;
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+ }
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+
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+ osize = isize + MPPE_OVHD + 2;
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+
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+ /*
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+ * Copy over the PPP header and set control bits.
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|
|
+ */
|
|
|
+ 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;
|
|
|
+ if (state->debug >= 7)
|
|
|
+ printk(KERN_DEBUG "mppe_compress[%d]: ccount %d\n", state->unit,
|
|
|
+ state->ccount);
|
|
|
+ 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 */
|
|
|
+ setup_sg(sg_in, ibuf, isize);
|
|
|
+ setup_sg(sg_out, obuf, osize);
|
|
|
+ if (crypto_cipher_encrypt(state->arc4, 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;
|
|
|
+ unsigned ccount;
|
|
|
+ int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED;
|
|
|
+ int sanity = 0;
|
|
|
+ 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;
|
|
|
+ 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); /* +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.
|
|
|
+ */
|
|
|
+ setup_sg(sg_in, ibuf, 1);
|
|
|
+ setup_sg(sg_out, obuf, 1);
|
|
|
+ if (crypto_cipher_decrypt(state->arc4, 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_cipher_decrypt(state->arc4, sg_out, sg_in, isize - 1) != 0) {
|
|
|
+ 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;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * 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_alg_available("arc4", 0) &&
|
|
|
+ crypto_alg_available("sha1", 0)))
|
|
|
+ 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);
|
Matt Domsch