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freebsd-dev/sys/netgraph/ng_mppc.c

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/*
* ng_mppc.c
*/
/*-
* Copyright (c) 1996-2000 Whistle Communications, Inc.
* All rights reserved.
*
* Subject to the following obligations and disclaimer of warranty, use and
* redistribution of this software, in source or object code forms, with or
* without modifications are expressly permitted by Whistle Communications;
* provided, however, that:
* 1. Any and all reproductions of the source or object code must include the
* copyright notice above and the following disclaimer of warranties; and
* 2. No rights are granted, in any manner or form, to use Whistle
* Communications, Inc. trademarks, including the mark "WHISTLE
* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
* such appears in the above copyright notice or in the software.
*
* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* Author: Archie Cobbs <archie@freebsd.org>
*
* $Whistle: ng_mppc.c,v 1.4 1999/11/25 00:10:12 archie Exp $
* $FreeBSD$
*/
/*
* Microsoft PPP compression (MPPC) and encryption (MPPE) netgraph node type.
*
* You must define one or both of the NETGRAPH_MPPC_COMPRESSION and/or
* NETGRAPH_MPPC_ENCRYPTION options for this node type to be useful.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_mppc.h>
#include "opt_netgraph.h"
#if !defined(NETGRAPH_MPPC_COMPRESSION) && !defined(NETGRAPH_MPPC_ENCRYPTION)
#ifdef KLD_MODULE
/* XXX NETGRAPH_MPPC_COMPRESSION isn't functional yet */
#define NETGRAPH_MPPC_ENCRYPTION
#else
/* This case is indicative of an error in sys/conf files */
#error Need either NETGRAPH_MPPC_COMPRESSION or NETGRAPH_MPPC_ENCRYPTION
#endif
#endif
#ifdef NG_SEPARATE_MALLOC
static MALLOC_DEFINE(M_NETGRAPH_MPPC, "netgraph_mppc", "netgraph mppc node");
#else
#define M_NETGRAPH_MPPC M_NETGRAPH
#endif
#ifdef NETGRAPH_MPPC_COMPRESSION
/* XXX this file doesn't exist yet, but hopefully someday it will... */
#include <net/mppc.h>
#endif
#ifdef NETGRAPH_MPPC_ENCRYPTION
#include <crypto/rc4/rc4.h>
#endif
#include <crypto/sha1.h>
/* Decompression blowup */
#define MPPC_DECOMP_BUFSIZE 8092 /* allocate buffer this big */
#define MPPC_DECOMP_SAFETY 100 /* plus this much margin */
/* MPPC/MPPE header length */
#define MPPC_HDRLEN 2
/* Key length */
#define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8)
/*
* When packets are lost with MPPE, we may have to re-key arbitrarily
* many times to 'catch up' to the new jumped-ahead sequence number.
* Since this can be expensive, we pose a limit on how many re-keyings
* we will do at one time to avoid a possible D.O.S. vulnerability.
* This should instead be a configurable parameter.
*/
#define MPPE_MAX_REKEY 1000
SYSCTL_NODE(_net_graph, OID_AUTO, mppe, CTLFLAG_RW, 0, "MPPE");
static int mppe_block_on_max_rekey = 0;
SYSCTL_INT(_net_graph_mppe, OID_AUTO, block_on_max_rekey, CTLFLAG_RWTUN,
&mppe_block_on_max_rekey, 0, "Block node on max MPPE key re-calculations");
static int mppe_log_max_rekey = 1;
SYSCTL_INT(_net_graph_mppe, OID_AUTO, log_max_rekey, CTLFLAG_RWTUN,
&mppe_log_max_rekey, 0, "Log max MPPE key re-calculations event");
static int mppe_max_rekey = MPPE_MAX_REKEY;
SYSCTL_INT(_net_graph_mppe, OID_AUTO, max_rekey, CTLFLAG_RWTUN,
&mppe_max_rekey, 0, "Maximum number of MPPE key re-calculations");
/* MPPC packet header bits */
#define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */
#define MPPC_FLAG_RESTART 0x4000 /* compress history restart */
#define MPPC_FLAG_COMPRESSED 0x2000 /* packet is compresed */
#define MPPC_FLAG_ENCRYPTED 0x1000 /* packet is encrypted */
#define MPPC_CCOUNT_MASK 0x0fff /* sequence number mask */
#define MPPC_CCOUNT_INC(d) ((d) = (((d) + 1) & MPPC_CCOUNT_MASK))
#define MPPE_UPDATE_MASK 0xff /* coherency count when we're */
#define MPPE_UPDATE_FLAG 0xff /* supposed to update key */
#define MPPC_COMP_OK 0x05
#define MPPC_DECOMP_OK 0x05
/* Per direction info */
struct ng_mppc_dir {
struct ng_mppc_config cfg; /* configuration */
hook_p hook; /* netgraph hook */
u_int16_t cc:12; /* coherency count */
u_char flushed; /* clean history (xmit only) */
#ifdef NETGRAPH_MPPC_COMPRESSION
u_char *history; /* compression history */
#endif
#ifdef NETGRAPH_MPPC_ENCRYPTION
u_char key[MPPE_KEY_LEN]; /* session key */
struct rc4_state rc4; /* rc4 state */
#endif
};
/* Node private data */
struct ng_mppc_private {
struct ng_mppc_dir xmit; /* compress/encrypt config */
struct ng_mppc_dir recv; /* decompress/decrypt config */
ng_ID_t ctrlnode; /* path to controlling node */
};
typedef struct ng_mppc_private *priv_p;
/* Netgraph node methods */
static ng_constructor_t ng_mppc_constructor;
static ng_rcvmsg_t ng_mppc_rcvmsg;
static ng_shutdown_t ng_mppc_shutdown;
static ng_newhook_t ng_mppc_newhook;
static ng_rcvdata_t ng_mppc_rcvdata;
static ng_disconnect_t ng_mppc_disconnect;
/* Helper functions */
static int ng_mppc_compress(node_p node,
struct mbuf **datap);
static int ng_mppc_decompress(node_p node,
struct mbuf **datap);
#ifdef NETGRAPH_MPPC_ENCRYPTION
static void ng_mppc_getkey(const u_char *h, u_char *h2, int len);
static void ng_mppc_updatekey(u_int32_t bits,
u_char *key0, u_char *key, struct rc4_state *rc4);
#endif
static void ng_mppc_reset_req(node_p node);
/* Node type descriptor */
static struct ng_type ng_mppc_typestruct = {
.version = NG_ABI_VERSION,
.name = NG_MPPC_NODE_TYPE,
.constructor = ng_mppc_constructor,
.rcvmsg = ng_mppc_rcvmsg,
.shutdown = ng_mppc_shutdown,
.newhook = ng_mppc_newhook,
.rcvdata = ng_mppc_rcvdata,
.disconnect = ng_mppc_disconnect,
};
NETGRAPH_INIT(mppc, &ng_mppc_typestruct);
#ifdef NETGRAPH_MPPC_ENCRYPTION
/* Depend on separate rc4 module */
MODULE_DEPEND(ng_mppc, rc4, 1, 1, 1);
#endif
/* Fixed bit pattern to weaken keysize down to 40 or 56 bits */
static const u_char ng_mppe_weakenkey[3] = { 0xd1, 0x26, 0x9e };
#define ERROUT(x) do { error = (x); goto done; } while (0)
/************************************************************************
NETGRAPH NODE STUFF
************************************************************************/
/*
* Node type constructor
*/
static int
ng_mppc_constructor(node_p node)
{
priv_p priv;
/* Allocate private structure */
priv = malloc(sizeof(*priv), M_NETGRAPH_MPPC, M_WAITOK | M_ZERO);
NG_NODE_SET_PRIVATE(node, priv);
/* This node is not thread safe. */
NG_NODE_FORCE_WRITER(node);
/* Done */
return (0);
}
/*
* Give our OK for a hook to be added
*/
static int
ng_mppc_newhook(node_p node, hook_p hook, const char *name)
{
const priv_p priv = NG_NODE_PRIVATE(node);
hook_p *hookPtr;
/* Check hook name */
if (strcmp(name, NG_MPPC_HOOK_COMP) == 0)
hookPtr = &priv->xmit.hook;
else if (strcmp(name, NG_MPPC_HOOK_DECOMP) == 0)
hookPtr = &priv->recv.hook;
else
return (EINVAL);
/* See if already connected */
if (*hookPtr != NULL)
return (EISCONN);
/* OK */
*hookPtr = hook;
return (0);
}
/*
* Receive a control message
*/
static int
ng_mppc_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
const priv_p priv = NG_NODE_PRIVATE(node);
struct ng_mesg *resp = NULL;
int error = 0;
struct ng_mesg *msg;
NGI_GET_MSG(item, msg);
switch (msg->header.typecookie) {
case NGM_MPPC_COOKIE:
switch (msg->header.cmd) {
case NGM_MPPC_CONFIG_COMP:
case NGM_MPPC_CONFIG_DECOMP:
{
struct ng_mppc_config *const cfg
= (struct ng_mppc_config *)msg->data;
const int isComp =
msg->header.cmd == NGM_MPPC_CONFIG_COMP;
struct ng_mppc_dir *const d = isComp ?
&priv->xmit : &priv->recv;
/* Check configuration */
if (msg->header.arglen != sizeof(*cfg))
ERROUT(EINVAL);
if (cfg->enable) {
if ((cfg->bits & ~MPPC_VALID_BITS) != 0)
ERROUT(EINVAL);
#ifndef NETGRAPH_MPPC_COMPRESSION
if ((cfg->bits & MPPC_BIT) != 0)
ERROUT(EPROTONOSUPPORT);
#endif
#ifndef NETGRAPH_MPPC_ENCRYPTION
if ((cfg->bits & MPPE_BITS) != 0)
ERROUT(EPROTONOSUPPORT);
#endif
} else
cfg->bits = 0;
/* Save return address so we can send reset-req's */
if (!isComp)
priv->ctrlnode = NGI_RETADDR(item);
/* Configuration is OK, reset to it */
d->cfg = *cfg;
#ifdef NETGRAPH_MPPC_COMPRESSION
/* Initialize state buffers for compression */
if (d->history != NULL) {
free(d->history, M_NETGRAPH_MPPC);
d->history = NULL;
}
if ((cfg->bits & MPPC_BIT) != 0) {
d->history = malloc(isComp ?
MPPC_SizeOfCompressionHistory() :
MPPC_SizeOfDecompressionHistory(),
M_NETGRAPH_MPPC, M_NOWAIT);
if (d->history == NULL)
ERROUT(ENOMEM);
if (isComp)
MPPC_InitCompressionHistory(d->history);
else {
MPPC_InitDecompressionHistory(
d->history);
}
}
#endif
#ifdef NETGRAPH_MPPC_ENCRYPTION
/* Generate initial session keys for encryption */
if ((cfg->bits & MPPE_BITS) != 0) {
const int keylen = KEYLEN(cfg->bits);
bcopy(cfg->startkey, d->key, keylen);
ng_mppc_getkey(cfg->startkey, d->key, keylen);
if ((cfg->bits & MPPE_40) != 0)
bcopy(&ng_mppe_weakenkey, d->key, 3);
else if ((cfg->bits & MPPE_56) != 0)
bcopy(&ng_mppe_weakenkey, d->key, 1);
rc4_init(&d->rc4, d->key, keylen);
}
#endif
/* Initialize other state */
d->cc = 0;
d->flushed = 0;
break;
}
case NGM_MPPC_RESETREQ:
ng_mppc_reset_req(node);
break;
default:
error = EINVAL;
break;
}
break;
default:
error = EINVAL;
break;
}
done:
NG_RESPOND_MSG(error, node, item, resp);
NG_FREE_MSG(msg);
return (error);
}
/*
* Receive incoming data on our hook.
*/
static int
ng_mppc_rcvdata(hook_p hook, item_p item)
{
const node_p node = NG_HOOK_NODE(hook);
const priv_p priv = NG_NODE_PRIVATE(node);
int error;
struct mbuf *m;
NGI_GET_M(item, m);
/* Compress and/or encrypt */
if (hook == priv->xmit.hook) {
if (!priv->xmit.cfg.enable) {
NG_FREE_M(m);
NG_FREE_ITEM(item);
return (ENXIO);
}
if ((error = ng_mppc_compress(node, &m)) != 0) {
NG_FREE_ITEM(item);
return(error);
}
NG_FWD_NEW_DATA(error, item, priv->xmit.hook, m);
return (error);
}
/* Decompress and/or decrypt */
if (hook == priv->recv.hook) {
if (!priv->recv.cfg.enable) {
NG_FREE_M(m);
NG_FREE_ITEM(item);
return (ENXIO);
}
if ((error = ng_mppc_decompress(node, &m)) != 0) {
NG_FREE_ITEM(item);
if (error == EINVAL && priv->ctrlnode != 0) {
struct ng_mesg *msg;
/* Need to send a reset-request */
NG_MKMESSAGE(msg, NGM_MPPC_COOKIE,
NGM_MPPC_RESETREQ, 0, M_NOWAIT);
if (msg == NULL)
return (error);
NG_SEND_MSG_ID(error, node, msg,
priv->ctrlnode, 0);
}
return (error);
}
NG_FWD_NEW_DATA(error, item, priv->recv.hook, m);
return (error);
}
/* Oops */
panic("%s: unknown hook", __func__);
}
/*
* Destroy node
*/
static int
ng_mppc_shutdown(node_p node)
{
const priv_p priv = NG_NODE_PRIVATE(node);
/* Take down netgraph node */
#ifdef NETGRAPH_MPPC_COMPRESSION
if (priv->xmit.history != NULL)
free(priv->xmit.history, M_NETGRAPH_MPPC);
if (priv->recv.history != NULL)
free(priv->recv.history, M_NETGRAPH_MPPC);
#endif
bzero(priv, sizeof(*priv));
free(priv, M_NETGRAPH_MPPC);
NG_NODE_SET_PRIVATE(node, NULL);
NG_NODE_UNREF(node); /* let the node escape */
return (0);
}
/*
* Hook disconnection
*/
static int
ng_mppc_disconnect(hook_p hook)
{
const node_p node = NG_HOOK_NODE(hook);
const priv_p priv = NG_NODE_PRIVATE(node);
/* Zero out hook pointer */
if (hook == priv->xmit.hook)
priv->xmit.hook = NULL;
if (hook == priv->recv.hook)
priv->recv.hook = NULL;
/* Go away if no longer connected */
if ((NG_NODE_NUMHOOKS(node) == 0)
&& NG_NODE_IS_VALID(node))
ng_rmnode_self(node);
return (0);
}
/************************************************************************
HELPER STUFF
************************************************************************/
/*
* Compress/encrypt a packet and put the result in a new mbuf at *resultp.
* The original mbuf is not free'd.
*/
static int
ng_mppc_compress(node_p node, struct mbuf **datap)
{
const priv_p priv = NG_NODE_PRIVATE(node);
struct ng_mppc_dir *const d = &priv->xmit;
u_int16_t header;
struct mbuf *m = *datap;
/* We must own the mbuf chain exclusively to modify it. */
m = m_unshare(m, M_NOWAIT);
if (m == NULL)
return (ENOMEM);
/* Initialize */
header = d->cc;
/* Always set the flushed bit in stateless mode */
if (d->flushed || ((d->cfg.bits & MPPE_STATELESS) != 0)) {
header |= MPPC_FLAG_FLUSHED;
d->flushed = 0;
}
/* Compress packet (if compression enabled) */
#ifdef NETGRAPH_MPPC_COMPRESSION
if ((d->cfg.bits & MPPC_BIT) != 0) {
u_short flags = MPPC_MANDATORY_COMPRESS_FLAGS;
u_char *inbuf, *outbuf;
int outlen, inlen, ina;
u_char *source, *dest;
u_long sourceCnt, destCnt;
int rtn;
/* Work with contiguous regions of memory. */
inlen = m->m_pkthdr.len;
if (m->m_next == NULL) {
inbuf = mtod(m, u_char *);
ina = 0;
} else {
inbuf = malloc(inlen, M_NETGRAPH_MPPC, M_NOWAIT);
if (inbuf == NULL)
goto err1;
m_copydata(m, 0, inlen, (caddr_t)inbuf);
ina = 1;
}
outlen = MPPC_MAX_BLOWUP(inlen);
outbuf = malloc(outlen, M_NETGRAPH_MPPC, M_NOWAIT);
if (outbuf == NULL) {
if (ina)
free(inbuf, M_NETGRAPH_MPPC);
err1:
m_freem(m);
MPPC_InitCompressionHistory(d->history);
d->flushed = 1;
return (ENOMEM);
}
/* Prepare to compress */
source = inbuf;
sourceCnt = inlen;
dest = outbuf;
destCnt = outlen;
if ((d->cfg.bits & MPPE_STATELESS) == 0)
flags |= MPPC_SAVE_HISTORY;
/* Compress */
rtn = MPPC_Compress(&source, &dest, &sourceCnt,
&destCnt, d->history, flags, 0);
/* Check return value */
KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__));
if ((rtn & MPPC_EXPANDED) == 0
&& (rtn & MPPC_COMP_OK) == MPPC_COMP_OK) {
outlen -= destCnt;
header |= MPPC_FLAG_COMPRESSED;
if ((rtn & MPPC_RESTART_HISTORY) != 0)
header |= MPPC_FLAG_RESTART;
/* Replace m by the compresed one. */
m_copyback(m, 0, outlen, (caddr_t)outbuf);
if (m->m_pkthdr.len < outlen) {
m_freem(m);
m = NULL;
} else if (outlen < m->m_pkthdr.len)
m_adj(m, outlen - m->m_pkthdr.len);
}
d->flushed = (rtn & MPPC_EXPANDED) != 0
|| (flags & MPPC_SAVE_HISTORY) == 0;
if (ina)
free(inbuf, M_NETGRAPH_MPPC);
free(outbuf, M_NETGRAPH_MPPC);
/* Check mbuf chain reload result. */
if (m == NULL) {
if (!d->flushed) {
MPPC_InitCompressionHistory(d->history);
d->flushed = 1;
}
return (ENOMEM);
}
}
#endif
/* Now encrypt packet (if encryption enabled) */
#ifdef NETGRAPH_MPPC_ENCRYPTION
if ((d->cfg.bits & MPPE_BITS) != 0) {
struct mbuf *m1;
/* Set header bits */
header |= MPPC_FLAG_ENCRYPTED;
/* Update key if it's time */
if ((d->cfg.bits & MPPE_STATELESS) != 0
|| (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) {
ng_mppc_updatekey(d->cfg.bits,
d->cfg.startkey, d->key, &d->rc4);
} else if ((header & MPPC_FLAG_FLUSHED) != 0) {
/* Need to reset key if we say we did
and ng_mppc_updatekey wasn't called to do it also. */
rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
}
/* Encrypt packet */
m1 = m;
while (m1) {
rc4_crypt(&d->rc4, mtod(m1, u_char *),
mtod(m1, u_char *), m1->m_len);
m1 = m1->m_next;
}
}
#endif
/* Update coherency count for next time (12 bit arithmetic) */
MPPC_CCOUNT_INC(d->cc);
/* Install header */
M_PREPEND(m, MPPC_HDRLEN, M_NOWAIT);
if (m != NULL)
be16enc(mtod(m, void *), header);
*datap = m;
return (*datap == NULL ? ENOBUFS : 0);
}
/*
* Decompress/decrypt packet and put the result in a new mbuf at *resultp.
* The original mbuf is not free'd.
*/
static int
ng_mppc_decompress(node_p node, struct mbuf **datap)
{
const priv_p priv = NG_NODE_PRIVATE(node);
struct ng_mppc_dir *const d = &priv->recv;
u_int16_t header, cc;
u_int numLost;
struct mbuf *m = *datap;
/* We must own the mbuf chain exclusively to modify it. */
m = m_unshare(m, M_NOWAIT);
if (m == NULL)
return (ENOMEM);
/* Pull off header */
if (m->m_pkthdr.len < MPPC_HDRLEN) {
m_freem(m);
return (EINVAL);
}
header = be16dec(mtod(m, void *));
cc = (header & MPPC_CCOUNT_MASK);
m_adj(m, MPPC_HDRLEN);
/* Check for an unexpected jump in the sequence number */
numLost = ((cc - d->cc) & MPPC_CCOUNT_MASK);
/* If flushed bit set, we can always handle packet */
if ((header & MPPC_FLAG_FLUSHED) != 0) {
#ifdef NETGRAPH_MPPC_COMPRESSION
if (d->history != NULL)
MPPC_InitDecompressionHistory(d->history);
#endif
#ifdef NETGRAPH_MPPC_ENCRYPTION
if ((d->cfg.bits & MPPE_BITS) != 0) {
u_int rekey;
/* How many times are we going to have to re-key? */
rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ?
numLost : (numLost / (MPPE_UPDATE_MASK + 1));
if (rekey > mppe_max_rekey) {
if (mppe_block_on_max_rekey) {
if (mppe_log_max_rekey) {
log(LOG_ERR, "%s: too many (%d) packets"
" dropped, disabling node %p!\n",
__func__, numLost, node);
}
priv->recv.cfg.enable = 0;
goto failed;
} else {
if (mppe_log_max_rekey) {
log(LOG_ERR, "%s: %d packets"
" dropped, node %p\n",
__func__, numLost, node);
}
goto failed;
}
}
/* Re-key as necessary to catch up to peer */
while (d->cc != cc) {
if ((d->cfg.bits & MPPE_STATELESS) != 0
|| (d->cc & MPPE_UPDATE_MASK)
== MPPE_UPDATE_FLAG) {
ng_mppc_updatekey(d->cfg.bits,
d->cfg.startkey, d->key, &d->rc4);
}
MPPC_CCOUNT_INC(d->cc);
}
/* Reset key (except in stateless mode, see below) */
if ((d->cfg.bits & MPPE_STATELESS) == 0)
rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
}
#endif
d->cc = cc; /* skip over lost seq numbers */
numLost = 0; /* act like no packets were lost */
}
/* Can't decode non-sequential packets without a flushed bit */
if (numLost != 0)
goto failed;
/* Decrypt packet */
if ((header & MPPC_FLAG_ENCRYPTED) != 0) {
#ifdef NETGRAPH_MPPC_ENCRYPTION
struct mbuf *m1;
#endif
/* Are we not expecting encryption? */
if ((d->cfg.bits & MPPE_BITS) == 0) {
log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
__func__, "encrypted");
goto failed;
}
#ifdef NETGRAPH_MPPC_ENCRYPTION
/* Update key if it's time (always in stateless mode) */
if ((d->cfg.bits & MPPE_STATELESS) != 0
|| (d->cc & MPPE_UPDATE_MASK) == MPPE_UPDATE_FLAG) {
ng_mppc_updatekey(d->cfg.bits,
d->cfg.startkey, d->key, &d->rc4);
}
/* Decrypt packet */
m1 = m;
while (m1 != NULL) {
rc4_crypt(&d->rc4, mtod(m1, u_char *),
mtod(m1, u_char *), m1->m_len);
m1 = m1->m_next;
}
#endif
} else {
/* Are we expecting encryption? */
if ((d->cfg.bits & MPPE_BITS) != 0) {
log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
__func__, "unencrypted");
goto failed;
}
}
/* Update coherency count for next time (12 bit arithmetic) */
MPPC_CCOUNT_INC(d->cc);
/* Check for unexpected compressed packet */
if ((header & MPPC_FLAG_COMPRESSED) != 0
&& (d->cfg.bits & MPPC_BIT) == 0) {
log(LOG_ERR, "%s: rec'd unexpectedly %s packet",
__func__, "compressed");
failed:
m_freem(m);
return (EINVAL);
}
#ifdef NETGRAPH_MPPC_COMPRESSION
/* Decompress packet */
if ((header & MPPC_FLAG_COMPRESSED) != 0) {
int flags = MPPC_MANDATORY_DECOMPRESS_FLAGS;
u_char *inbuf, *outbuf;
int inlen, outlen, ina;
u_char *source, *dest;
u_long sourceCnt, destCnt;
int rtn;
/* Copy payload into a contiguous region of memory. */
inlen = m->m_pkthdr.len;
if (m->m_next == NULL) {
inbuf = mtod(m, u_char *);
ina = 0;
} else {
inbuf = malloc(inlen, M_NETGRAPH_MPPC, M_NOWAIT);
if (inbuf == NULL) {
m_freem(m);
return (ENOMEM);
}
m_copydata(m, 0, inlen, (caddr_t)inbuf);
ina = 1;
}
/* Allocate a buffer for decompressed data */
outbuf = malloc(MPPC_DECOMP_BUFSIZE + MPPC_DECOMP_SAFETY,
M_NETGRAPH_MPPC, M_NOWAIT);
if (outbuf == NULL) {
m_freem(m);
if (ina)
free(inbuf, M_NETGRAPH_MPPC);
return (ENOMEM);
}
outlen = MPPC_DECOMP_BUFSIZE;
/* Prepare to decompress */
source = inbuf;
sourceCnt = inlen;
dest = outbuf;
destCnt = outlen;
if ((header & MPPC_FLAG_RESTART) != 0)
flags |= MPPC_RESTART_HISTORY;
/* Decompress */
rtn = MPPC_Decompress(&source, &dest,
&sourceCnt, &destCnt, d->history, flags);
/* Check return value */
KASSERT(rtn != MPPC_INVALID, ("%s: invalid", __func__));
if ((rtn & MPPC_DEST_EXHAUSTED) != 0
|| (rtn & MPPC_DECOMP_OK) != MPPC_DECOMP_OK) {
log(LOG_ERR, "%s: decomp returned 0x%x",
__func__, rtn);
if (ina)
free(inbuf, M_NETGRAPH_MPPC);
free(outbuf, M_NETGRAPH_MPPC);
goto failed;
}
/* Replace compressed data with decompressed data */
if (ina)
free(inbuf, M_NETGRAPH_MPPC);
outlen -= destCnt;
m_copyback(m, 0, outlen, (caddr_t)outbuf);
if (m->m_pkthdr.len < outlen) {
m_freem(m);
m = NULL;
} else if (outlen < m->m_pkthdr.len)
m_adj(m, outlen - m->m_pkthdr.len);
free(outbuf, M_NETGRAPH_MPPC);
}
#endif
/* Return result in an mbuf */
*datap = m;
return (*datap == NULL ? ENOBUFS : 0);
}
/*
* The peer has sent us a CCP ResetRequest, so reset our transmit state.
*/
static void
ng_mppc_reset_req(node_p node)
{
const priv_p priv = NG_NODE_PRIVATE(node);
struct ng_mppc_dir *const d = &priv->xmit;
#ifdef NETGRAPH_MPPC_COMPRESSION
if (d->history != NULL)
MPPC_InitCompressionHistory(d->history);
#endif
#ifdef NETGRAPH_MPPC_ENCRYPTION
if ((d->cfg.bits & MPPE_STATELESS) == 0)
rc4_init(&d->rc4, d->key, KEYLEN(d->cfg.bits));
#endif
d->flushed = 1;
}
#ifdef NETGRAPH_MPPC_ENCRYPTION
/*
* Generate a new encryption key
*/
static void
ng_mppc_getkey(const u_char *h, u_char *h2, int len)
{
static const u_char pad1[40] =
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
static const u_char pad2[40] =
{ 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2,
0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2,
0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2,
0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2 };
u_char hash[20];
SHA1_CTX c;
SHA1Init(&c);
SHA1Update(&c, h, len);
SHA1Update(&c, pad1, sizeof(pad1));
SHA1Update(&c, h2, len);
SHA1Update(&c, pad2, sizeof(pad2));
SHA1Final(hash, &c);
bcopy(hash, h2, len);
}
/*
* Update the encryption key
*/
static void
ng_mppc_updatekey(u_int32_t bits,
u_char *key0, u_char *key, struct rc4_state *rc4)
{
const int keylen = KEYLEN(bits);
ng_mppc_getkey(key0, key, keylen);
rc4_init(rc4, key, keylen);
rc4_crypt(rc4, key, key, keylen);
if ((bits & MPPE_40) != 0)
bcopy(&ng_mppe_weakenkey, key, 3);
else if ((bits & MPPE_56) != 0)
bcopy(&ng_mppe_weakenkey, key, 1);
rc4_init(rc4, key, keylen);
}
#endif
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