* RFC: [0/3] PPP MPPE module @ 2004-06-18 16:10 Matt Domsch 2004-06-18 16:10 ` RFC: [1/3] " Matt Domsch 2004-06-18 16:12 ` RFC: [1/2] " Matt Domsch 0 siblings, 2 replies; 7+ messages in thread From: Matt Domsch @ 2004-06-18 16:10 UTC (permalink / raw) To: netdev, pptpclient-devel [-- Attachment #1: Type: text/plain, Size: 1009 bytes --] The pptpclient project at SourceForge has for several years maintained the PPP MPPE (Microsoft Point-to-Point Encryption) ppp compressor/decompressor module outside of the Linux kernel tree, as it has needed arc4 and sha1 crypto routines which were not in-kernel yet. As they now are, I'd like to submit this code for review, and when deemed ready, inclusion, into 2.6.x. MPPE is a requirement for connecting Linux clients to Linux and Microsoft PPTP (Point to Point Tunneling Protocol) servers. Following two emails each contain patches. 1) Add ppp_mppe.c file to drivers/net 2) minimal touches to Makefile, KConfig, ppp_generic.c, and include/linux/ppp-comp.h I've asked that the pptpclient-devel list be opened to posts by non-subscribers during this review period at least. Feedback welcome. Thanks, Matt -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com [-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --] ^ permalink raw reply [flat|nested] 7+ messages in thread
* RFC: [1/3] PPP MPPE module 2004-06-18 16:10 RFC: [0/3] PPP MPPE module Matt Domsch @ 2004-06-18 16:10 ` Matt Domsch 2004-06-18 18:03 ` Stephen Hemminger 2004-06-18 16:12 ` RFC: [1/2] " Matt Domsch 1 sibling, 1 reply; 7+ messages in thread From: Matt Domsch @ 2004-06-18 16:10 UTC (permalink / raw) To: netdev, pptpclient-devel [-- Attachment #1: Type: text/plain, Size: 22156 bytes --] On Fri, Jun 18, 2004 at 11:10:01AM -0500, Matt Domsch wrote: > 1) Add ppp_mppe.c file to drivers/net -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com --- /dev/null Thu Apr 11 09:25:15 2002 +++ linux-2.6-mppe/drivers/net/ppp_mppe.c Fri Jun 18 10:42:11 2004 @@ -0,0 +1,695 @@ +/* + * ppp_mppe_compress.c - interface MPPE to the PPP code. + * This version is for use with Linux kernel 2.2.19+, 2.4.18+ and 2.6.2+. + * + * By Frank Cusack <frank@google.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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * + * Changelog: + * 06/18/04 - Matt Domsch <Matt_Domsch@dell.com> + * 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/module.h> +#include <linux/kernel.h> +#include <linux/version.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 <asm/scatterlist.h> + +#include <linux/ppp_defs.h> +#include <linux/ppp-comp.h> + +static void +setup_sg(struct scatterlist *sg, const void *address, unsigned int length) +{ + sg[0].page = virt_to_page(address); + sg[0].offset = offset_in_page(address); + + if (sg[0].offset + length <= PAGE_SIZE) { + sg[0].length = length; + sg[1].page = 0; + sg[1].offset = 0; + sg[1].length = 0; + } else { + sg[0].length = PAGE_SIZE - sg[0].offset; + sg[1].length = length - sg[0].length; + sg[1].page = virt_to_page(address + sg[0].length); + sg[1].offset = offset_in_page(address + sg[0].length); /* 0 */ + } +} + +/* + * State for an MPPE (de)compressor. + */ +typedef struct ppp_mppe_state { + struct crypto_tfm *arc4; + struct crypto_tfm *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; +} 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 */ + +#define MPPE_OVHD 2 /* MPPE overhead/packet */ +#define SANITY_MAX 1600 /* Max bogon factor we will tolerate */ + +#define SHA1_PAD_SIZE 40 +/* + * Key Derivation, from RFC 3078, RFC 3079. + * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079. + */ +static void GetNewKeyFromSHA(ppp_mppe_state * state, unsigned char *InterimKey) +{ + static const unsigned char SHApad1[SHA1_PAD_SIZE] = + { 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 + }; + static const unsigned char SHApad2[SHA1_PAD_SIZE] = + { 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 + }; + struct scatterlist sg[2]; + + crypto_digest_init(state->sha1); + setup_sg(sg, state->master_key, state->keylen); + crypto_digest_update(state->sha1, sg, state->keylen); + setup_sg(sg, SHApad1, sizeof(SHApad1)); + crypto_digest_update(state->sha1, sg, sizeof(SHApad1)); + setup_sg(sg, state->session_key, state->keylen); + crypto_digest_update(state->sha1, sg, state->keylen); + setup_sg(sg, SHApad2, sizeof(SHApad2)); + crypto_digest_update(state->sha1, sg, sizeof(SHApad2)); + crypto_digest_final(state->sha1, state->sha1_digest); + memcpy(InterimKey, state->sha1_digest, state->keylen); +} + +/* + * 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]; + struct scatterlist sg_in[2], sg_out[2]; + + GetNewKeyFromSHA(state, InterimKey); + if (!initial_key) { + crypto_cipher_setkey(state->arc4, InterimKey, state->keylen); + setup_sg(sg_in, InterimKey, state->keylen); + setup_sg(sg_out, state->session_key, state->keylen); + crypto_cipher_encrypt(state->arc4, sg_out, sg_in, + state->keylen); + } 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; + } + crypto_cipher_setkey(state->arc4, state->session_key, state->keylen); +} + +/* + * Allocate space for a (de)compressor. + */ +static void *mppe_alloc(unsigned char *options, int optlen) +{ + 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 = (ppp_mppe_state *) kmalloc(sizeof(*state), GFP_KERNEL); + if (state == NULL) + goto out; + + memset(state, 0, sizeof(*state)); + + state->arc4 = crypto_alloc_tfm("arc4", 0); + if (!state->arc4) + goto out_free; + state->sha1 = crypto_alloc_tfm("sha1", 0); + if (!state->sha1) + goto out_arc4; + digestsize = crypto_tfm_alg_digestsize(state->sha1); + if (digestsize < MPPE_MAX_KEY_LEN) + goto out_sha1; + state->sha1_digest = kmalloc(digestsize, GFP_KERNEL); + if (!state->sha1_digest) + goto out_sha1; + + /* 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_sha1: + crypto_free_tfm(state->sha1); + out_arc4: + crypto_free_tfm(state->arc4); + out_free: + kfree(state); + out: + return NULL; +} + +/* + * Deallocate space for a (de)compressor. + */ +static void mppe_free(void *arg) +{ + ppp_mppe_state *state = (ppp_mppe_state *) arg; + + if (state) { + if (state->arc4) + crypto_free_tfm(state->arc4); + if (state->sha1) + crypto_free_tfm(state->sha1); + if (state->sha1_digest) + kfree(state->sha1_digest); + kfree(state); + } +} + +/* + * 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) * 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, "%.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; + struct scatterlist sg_in[2], sg_out[2]; + + /* + * 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; + 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); + crypto_cipher_encrypt(state->arc4, sg_out, sg_in, isize); + + 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; + struct scatterlist sg_in[2], sg_out[2]; + + 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); + crypto_cipher_decrypt(state->arc4, sg_out, sg_in, 1); + + /* + * 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); + crypto_cipher_decrypt(state->arc4, sg_out, sg_in, isize - 1); + + 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 + *************************************************************/ + +/* + * 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 */ +}; + +/* + * 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. + */ + +int __init ppp_mppe_init(void) +{ + if (!(crypto_alg_available("arc4", 0) && + crypto_alg_available("sha1", 0))) + return -ENODEV; + + int answer = ppp_register_compressor(&ppp_mppe); + + if (answer == 0) + printk(KERN_INFO "PPP MPPE Compression module registered\n"); + return answer; +} + +void __exit ppp_mppe_cleanup(void) +{ + ppp_unregister_compressor(&ppp_mppe); +} + +module_init(ppp_mppe_init); +module_exit(ppp_mppe_cleanup); +MODULE_LICENSE("Dual BSD/GPL"); [-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --] ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RFC: [1/3] PPP MPPE module 2004-06-18 16:10 ` RFC: [1/3] " Matt Domsch @ 2004-06-18 18:03 ` Stephen Hemminger 2004-06-18 19:31 ` [pptp-devel] " Matt Domsch 0 siblings, 1 reply; 7+ messages in thread From: Stephen Hemminger @ 2004-06-18 18:03 UTC (permalink / raw) To: Matt Domsch; +Cc: netdev, pptpclient-devel Minor stuff. > +/* > + * State for an MPPE (de)compressor. > + */ > +typedef struct ppp_mppe_state { > + struct crypto_tfm *arc4; > + struct crypto_tfm *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; > +} ppp_mppe_state; Is the typedef really making things clearer? no. > +/* 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 */ > + > +#define SHA1_PAD_SIZE 40 > +/* > + * Key Derivation, from RFC 3078, RFC 3079. > + * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079. > + */ > +static void GetNewKeyFromSHA(ppp_mppe_state * state, unsigned char *InterimKey) annoying RandomCaptialization > > +/* > + * 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) > +{ This can be static since only call should be through table. > + > +/* > + * Decompress (decrypt) an MPPE packet. > + */ > +int > +mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf, > + int osize) > +{ Also can be static. > + > +/************************************************************* > + * Module interface table > + *************************************************************/ > + > +/* > + * 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 */ > +}; Table can be static since it is hooked in with register call. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [pptp-devel] Re: RFC: [1/3] PPP MPPE module 2004-06-18 18:03 ` Stephen Hemminger @ 2004-06-18 19:31 ` Matt Domsch 0 siblings, 0 replies; 7+ messages in thread From: Matt Domsch @ 2004-06-18 19:31 UTC (permalink / raw) To: Stephen Hemminger; +Cc: netdev, pptpclient-devel [-- Attachment #1: Type: text/plain, Size: 325 bytes --] On Fri, Jun 18, 2004 at 11:03:50AM -0700, Stephen Hemminger wrote: > Minor stuff. All valid. I'll clean them up in the next pass. Thanks, Matt -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com [-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --] ^ permalink raw reply [flat|nested] 7+ messages in thread
* RFC: [1/2] PPP MPPE module 2004-06-18 16:10 RFC: [0/3] PPP MPPE module Matt Domsch 2004-06-18 16:10 ` RFC: [1/3] " Matt Domsch @ 2004-06-18 16:12 ` Matt Domsch 2004-06-18 16:15 ` Christoph Hellwig 1 sibling, 1 reply; 7+ messages in thread From: Matt Domsch @ 2004-06-18 16:12 UTC (permalink / raw) To: netdev, pptpclient-devel [-- Attachment #1: Type: text/plain, Size: 8761 bytes --] On Fri, Jun 18, 2004 at 11:10:01AM -0500, Matt Domsch wrote: > Following two emails each contain patches. Of course, that subject should have been [0,1,2/2], not of 3. > 2) minimal touches to Makefile, KConfig, ppp_generic.c, and > include/linux/ppp-comp.h -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com ===== drivers/net/Kconfig 1.75 vs edited ===== --- 1.75/drivers/net/Kconfig 2004-06-02 15:04:38 -05:00 +++ edited/drivers/net/Kconfig 2004-06-18 09:48:16 -05:00 @@ -2410,6 +2410,12 @@ module; it is called bsd_comp and will show up in the directory modules once you have said "make modules". If unsure, say N. +config PPP_MPPE + tristate "PPP MPPE compression (encryption)" + depends on PPP + ---help--- + Support for the MPPE Encryption protocol. + config PPPOE tristate "PPP over Ethernet (EXPERIMENTAL)" depends on EXPERIMENTAL && PPP ===== drivers/net/Makefile 1.79 vs edited ===== --- 1.79/drivers/net/Makefile 2004-05-22 12:13:08 -05:00 +++ edited/drivers/net/Makefile 2004-06-18 10:22:41 -05:00 @@ -100,6 +100,7 @@ obj-$(CONFIG_PPP_SYNC_TTY) += ppp_synctty.o obj-$(CONFIG_PPP_DEFLATE) += ppp_deflate.o obj-$(CONFIG_PPP_BSDCOMP) += bsd_comp.o +obj-$(CONFIG_PPP_MPPE) += ppp_mppe.o obj-$(CONFIG_PPPOE) += pppox.o pppoe.o obj-$(CONFIG_SLIP) += slip.o ===== drivers/net/ppp_generic.c 1.45 vs edited ===== --- 1.45/drivers/net/ppp_generic.c 2004-04-09 18:21:06 -05:00 +++ edited/drivers/net/ppp_generic.c 2004-06-18 09:47:10 -05:00 @@ -1066,8 +1066,15 @@ /* try to do packet compression */ if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0 && proto != PPP_LCP && proto != PPP_CCP) { - new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len, - GFP_ATOMIC); + int new_skb_size = ppp->dev->mtu + ppp->dev->hard_header_len; + int compressor_skb_size = ppp->dev->mtu + PPP_HDRLEN; + + if (ppp->xcomp->compress_proto == CI_MPPE) { + /* CCP [must have] reduced MTU by MPPE_PAD. */ + new_skb_size += MPPE_PAD; + compressor_skb_size += MPPE_PAD; + } + new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); if (new_skb == 0) { printk(KERN_ERR "PPP: no memory (comp pkt)\n"); goto drop; @@ -1079,15 +1086,27 @@ /* compressor still expects A/C bytes in hdr */ len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, new_skb->data, skb->len + 2, - ppp->dev->mtu + PPP_HDRLEN); + compressor_skb_size); if (len > 0 && (ppp->flags & SC_CCP_UP)) { kfree_skb(skb); skb = new_skb; skb_put(skb, len); skb_pull(skb, 2); /* pull off A/C bytes */ - } else { + } else if (len == 0) { /* didn't compress, or CCP not up yet */ kfree_skb(new_skb); + } else { + /* + * (len < 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); + goto drop; } } @@ -1596,7 +1615,7 @@ goto err; if (proto == PPP_COMP) { - ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN); + ns = dev_alloc_skb(ppp->mru + 128 + PPP_HDRLEN); if (ns == 0) { printk(KERN_ERR "ppp_decompress_frame: no memory\n"); goto err; ===== include/linux/ppp-comp.h 1.4 vs edited ===== --- 1.4/include/linux/ppp-comp.h 2003-08-07 18:57:19 -05:00 +++ edited/include/linux/ppp-comp.h 2004-06-18 09:46:32 -05:00 @@ -191,6 +191,100 @@ #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 8 /* 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. */ [-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --] ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RFC: [1/2] PPP MPPE module 2004-06-18 16:12 ` RFC: [1/2] " Matt Domsch @ 2004-06-18 16:15 ` Christoph Hellwig 2004-06-21 16:39 ` Matt Domsch 0 siblings, 1 reply; 7+ messages in thread From: Christoph Hellwig @ 2004-06-18 16:15 UTC (permalink / raw) To: Matt Domsch; +Cc: netdev, pptpclient-devel, paulus Last time I talked to Paul on MPPE he didn't like those hacks in the ppp core. > --- 1.45/drivers/net/ppp_generic.c 2004-04-09 18:21:06 -05:00 > +++ edited/drivers/net/ppp_generic.c 2004-06-18 09:47:10 -05:00 > @@ -1066,8 +1066,15 @@ > /* try to do packet compression */ > if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0 > && proto != PPP_LCP && proto != PPP_CCP) { > - new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len, > - GFP_ATOMIC); > + int new_skb_size = ppp->dev->mtu + ppp->dev->hard_header_len; > + int compressor_skb_size = ppp->dev->mtu + PPP_HDRLEN; > + > + if (ppp->xcomp->compress_proto == CI_MPPE) { > + /* CCP [must have] reduced MTU by MPPE_PAD. */ > + new_skb_size += MPPE_PAD; > + compressor_skb_size += MPPE_PAD; > + } > + new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); > if (new_skb == 0) { > printk(KERN_ERR "PPP: no memory (comp pkt)\n"); > goto drop; > @@ -1079,15 +1086,27 @@ > /* compressor still expects A/C bytes in hdr */ > len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, > new_skb->data, skb->len + 2, > - ppp->dev->mtu + PPP_HDRLEN); > + compressor_skb_size); > if (len > 0 && (ppp->flags & SC_CCP_UP)) { > kfree_skb(skb); > skb = new_skb; > skb_put(skb, len); > skb_pull(skb, 2); /* pull off A/C bytes */ > - } else { > + } else if (len == 0) { > /* didn't compress, or CCP not up yet */ > kfree_skb(new_skb); > + } else { > + /* > + * (len < 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); > + goto drop; > } > } > > @@ -1596,7 +1615,7 @@ > goto err; > > if (proto == PPP_COMP) { > - ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN); > + ns = dev_alloc_skb(ppp->mru + 128 + PPP_HDRLEN); > if (ns == 0) { > printk(KERN_ERR "ppp_decompress_frame: no memory\n"); > goto err; > ===== include/linux/ppp-comp.h 1.4 vs edited ===== > --- 1.4/include/linux/ppp-comp.h 2003-08-07 18:57:19 -05:00 > +++ edited/include/linux/ppp-comp.h 2004-06-18 09:46:32 -05:00 > @@ -191,6 +191,100 @@ > #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 8 /* 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. > */ > ---end quoted text--- ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RFC: [1/2] PPP MPPE module 2004-06-18 16:15 ` Christoph Hellwig @ 2004-06-21 16:39 ` Matt Domsch 0 siblings, 0 replies; 7+ messages in thread From: Matt Domsch @ 2004-06-21 16:39 UTC (permalink / raw) To: Christoph Hellwig, linux-ppp; +Cc: netdev, pptpclient-devel, paulus [-- Attachment #1: Type: text/plain, Size: 4910 bytes --] On Fri, Jun 18, 2004 at 05:15:58PM +0100, Christoph Hellwig wrote: > Last time I talked to Paul on MPPE he didn't like those hacks in > the ppp core. Adding the linux-ppp list to the discussion. Rather than have code in ppp_generic.c testing for CI_MPPE and doing code conditionally (which I agree was ugly), how about adding two new fields to struct compressor: + /* Extra skb space needed by the compressor algorithm */ + unsigned int comp_skb_extra_space; + /* Extra skb space needed by the decompressor algorithm */ + unsigned int decomp_skb_extra_space; which the compressor modules can fill in if needed? Presently, bsd_comp.c and ppp_deflate.c don't need these, so they will be filled with zeros automatically at struct compressor instantiation. This hunk may still be contriversial though. It adds a negative return value to the compress() method, which is only (presently) used by ppp_mppe (bsd_comp.c and ppp_deflate.c always return 0 if they couldn't compress), to indicate the frame should be dropped. - } else { + } else if (len == 0) { /* didn't compress, or CCP not up yet */ kfree_skb(new_skb); + } else { + /* + * (len < 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); + goto drop; Thoughts? Patch below against 2.6.7-bk ppp_generic.c and ppp-comp.h to add such, for comment only. Thanks, Matt -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com ===== drivers/net/ppp_generic.c 1.45 vs edited ===== --- 1.45/drivers/net/ppp_generic.c 2004-04-09 18:21:06 -05:00 +++ edited/drivers/net/ppp_generic.c 2004-06-21 10:56:34 -05:00 @@ -1066,8 +1066,9 @@ /* try to do packet compression */ if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0 && proto != PPP_LCP && proto != PPP_CCP) { - new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len, - GFP_ATOMIC); + int new_skb_size = ppp->dev->mtu + ppp->xcomp->comp_skb_extra_space + ppp->dev->hard_header_len; + int compressor_skb_size = ppp->dev->mtu + ppp->xcomp->comp_skb_extra_space + PPP_HDRLEN; + new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); if (new_skb == 0) { printk(KERN_ERR "PPP: no memory (comp pkt)\n"); goto drop; @@ -1079,15 +1080,27 @@ /* compressor still expects A/C bytes in hdr */ len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, new_skb->data, skb->len + 2, - ppp->dev->mtu + PPP_HDRLEN); + compressor_skb_size); if (len > 0 && (ppp->flags & SC_CCP_UP)) { kfree_skb(skb); skb = new_skb; skb_put(skb, len); skb_pull(skb, 2); /* pull off A/C bytes */ - } else { + } else if (len == 0) { /* didn't compress, or CCP not up yet */ kfree_skb(new_skb); + } else { + /* + * (len < 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); + goto drop; } } @@ -1596,7 +1609,7 @@ goto err; if (proto == PPP_COMP) { - ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN); + ns = dev_alloc_skb(ppp->mru + ppp->rcomp->decomp_skb_extra_space + PPP_HDRLEN); if (ns == 0) { printk(KERN_ERR "ppp_decompress_frame: no memory\n"); goto err; ===== include/linux/ppp-comp.h 1.4 vs edited ===== --- 1.4/include/linux/ppp-comp.h 2003-08-07 18:57:19 -05:00 +++ edited/include/linux/ppp-comp.h 2004-06-21 10:59:44 -05:00 @@ -111,6 +111,10 @@ /* Used in locking compressor modules */ struct module *owner; + /* Extra skb space needed by the compressor algorithm */ + unsigned int comp_skb_extra_space; + /* Extra skb space needed by the decompressor algorithm */ + unsigned int decomp_skb_extra_space; }; /* [-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --] ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2004-06-21 16:39 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2004-06-18 16:10 RFC: [0/3] PPP MPPE module Matt Domsch 2004-06-18 16:10 ` RFC: [1/3] " Matt Domsch 2004-06-18 18:03 ` Stephen Hemminger 2004-06-18 19:31 ` [pptp-devel] " Matt Domsch 2004-06-18 16:12 ` RFC: [1/2] " Matt Domsch 2004-06-18 16:15 ` Christoph Hellwig 2004-06-21 16:39 ` Matt Domsch
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