/
xform_tcp.c
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/
xform_tcp.c
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/* $NetBSD: xform_tcp.c,v 1.3 2005/12/11 12:25:06 christos Exp $ */
/* $FreeBSD: sys/netipsec/xform_tcp.c,v 1.1.2.1 2004/02/14 22:24:09 bms Exp $ */
/*
* Copyright (c) 2003 Bruce M. Simpson <bms@spc.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 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 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* TCP MD5 Signature Option (RFC2385) */
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/lock.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <net/route.h>
#include <netipsec/ipsec.h>
#include <netipsec/xform.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netipsec/ipsec6.h>
#endif
#include <netipsec/key.h>
#include <netipsec/key_debug.h>
/*
* Initialize a TCP-MD5 SA. Called when the SA is being set up.
*
* We don't need to set up the tdb prefixed fields, as we don't use the
* opencrypto code; we just perform a key length check.
*
* XXX: Currently we only allow a single 'magic' SPI to be used.
*
* This allows per-host granularity without affecting the userland
* interface, which is a simple socket option toggle switch,
* TCP_SIGNATURE_ENABLE.
*
* To allow per-service granularity requires that we have a means
* of mapping port to SPI. The mandated way of doing this is to
* use SPD entries to specify packet flows which get the TCP-MD5
* treatment, however the code to do this is currently unstable
* and unsuitable for production use.
*
* Therefore we use this compromise in the meantime.
*/
static int
tcpsignature_init(struct secasvar *sav, struct xformsw *xsp)
{
int keylen;
if (sav->spi != htonl(TCP_SIG_SPI)) {
DPRINTF(("%s: SPI %x must be TCP_SIG_SPI (0x1000)\n",
__func__, sav->alg_auth));
return (EINVAL);
}
if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
DPRINTF(("%s: unsupported authentication algorithm %u\n",
__func__, sav->alg_auth));
return (EINVAL);
}
if (sav->key_auth == NULL) {
DPRINTF(("%s: no authentication key present\n", __func__));
return (EINVAL);
}
keylen = _KEYLEN(sav->key_auth);
if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
DPRINTF(("%s: invalid key length %u\n", __func__, keylen));
return (EINVAL);
}
return (0);
}
/*
* Paranoia.
*
* Called when the SA is deleted.
*/
static int
tcpsignature_zeroize(struct secasvar *sav)
{
if (sav->key_auth)
bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
sav->tdb_cryptoid = 0;
sav->tdb_authalgxform = NULL;
sav->tdb_xform = NULL;
return (0);
}
/*
* Verify that an input packet passes authentication.
* Called from the ipsec layer.
* We do this from within tcp itself, so this routine is just a stub.
*/
static int
tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip,
int protoff)
{
return (0);
}
/*
* Prepend the authentication header.
* Called from the ipsec layer.
* We do this from within tcp itself, so this routine is just a stub.
*/
static int
tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr,
struct mbuf **mp, int skip, int protoff)
{
return (EINVAL);
}
static struct xformsw tcpsignature_xformsw = {
XF_TCPSIGNATURE, XFT_AUTH, "TCPMD5",
tcpsignature_init, tcpsignature_zeroize,
tcpsignature_input, tcpsignature_output
};
INITFN void
tcpsignature_attach(void)
{
xform_register(&tcpsignature_xformsw);
}
#ifdef __FreeBSD__
SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST,
tcpsignature_attach, NULL)
#endif