NetBSD/sys/netipsec/xform_tcp.c

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Initial commit of a port of the FreeBSD implementation of RFC 2385 (MD5 signatures for TCP, as used with BGP). Credit for original FreeBSD code goes to Bruce M. Simpson, with FreeBSD sponsorship credited to sentex.net. Shortening of the setsockopt() name attributed to Vincent Jardin. This commit is a minimal, working version of the FreeBSD code, as MFC'ed to FreeBSD-4. It has received minimal testing with a ttcp modified to set the TCP-MD5 option; BMS's additions to tcpdump-current (tcpdump -M) confirm that the MD5 signatures are correct. Committed as-is for further testing between a NetBSD BGP speaker (e.g., quagga) and industry-standard BGP speakers (e.g., Cisco, Juniper). NOTE: This version has two potential flaws. First, I do see any code that verifies recieved TCP-MD5 signatures. Second, the TCP-MD5 options are internally padded and assumed to be 32-bit aligned. A more space-efficient scheme is to pack all TCP options densely (and possibly unaligned) into the TCP header ; then do one final padding to a 4-byte boundary. Pre-existing comments note that accounting for TCP-option space when we add SACK is yet to be done. For now, I'm punting on that; we can solve it properly, in a way that will handle SACK blocks, as a separate exercise. In case a pullup to NetBSD-2 is requested, this adds sys/netipsec/xform_tcp.c ,and modifies: sys/net/pfkeyv2.h,v 1.15 sys/netinet/files.netinet,v 1.5 sys/netinet/ip.h,v 1.25 sys/netinet/tcp.h,v 1.15 sys/netinet/tcp_input.c,v 1.200 sys/netinet/tcp_output.c,v 1.109 sys/netinet/tcp_subr.c,v 1.165 sys/netinet/tcp_usrreq.c,v 1.89 sys/netinet/tcp_var.h,v 1.109 sys/netipsec/files.netipsec,v 1.3 sys/netipsec/ipsec.c,v 1.11 sys/netipsec/ipsec.h,v 1.7 sys/netipsec/key.c,v 1.11 share/man/man4/tcp.4,v 1.16 lib/libipsec/pfkey.c,v 1.20 lib/libipsec/pfkey_dump.c,v 1.17 lib/libipsec/policy_token.l,v 1.8 sbin/setkey/parse.y,v 1.14 sbin/setkey/setkey.8,v 1.27 sbin/setkey/token.l,v 1.15 Note that the preceding two revisions to tcp.4 will be required to cleanly apply this diff.
2004-04-26 02:25:03 +04:00
/* $NetBSD: xform_tcp.c,v 1.1 2004/04/25 22:25:03 jonathan 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