170 lines
4.7 KiB
C
170 lines
4.7 KiB
C
/* $FreeBSD$ */
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/*
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* Copyright (c) 2003 Bruce M. Simpson <bms@spc.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* TCP MD5 Signature Option (RFC2385) */
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/lock.h>
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#include <sys/socket.h>
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#include <sys/kernel.h>
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#include <sys/protosw.h>
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#include <sys/sysctl.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_var.h>
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#include <net/route.h>
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#include <netipsec/ipsec.h>
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#include <netipsec/xform.h>
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#ifdef INET6
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#include <netinet/ip6.h>
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#include <netipsec/ipsec6.h>
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#endif
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#include <netipsec/key.h>
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#include <netipsec/key_debug.h>
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/*
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* Initialize a TCP-MD5 SA. Called when the SA is being set up.
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*
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* We don't need to set up the tdb prefixed fields, as we don't use the
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* opencrypto code; we just perform a key length check.
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*
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* XXX: Currently we only allow a single 'magic' SPI to be used.
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*
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* This allows per-host granularity without affecting the userland
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* interface, which is a simple socket option toggle switch,
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* TCP_SIGNATURE_ENABLE.
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*
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* To allow per-service granularity requires that we have a means
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* of mapping port to SPI. The mandated way of doing this is to
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* use SPD entries to specify packet flows which get the TCP-MD5
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* treatment, however the code to do this is currently unstable
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* and unsuitable for production use.
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*
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* Therefore we use this compromise in the meantime.
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*/
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static int
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tcpsignature_init(struct secasvar *sav, struct xformsw *xsp)
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{
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int keylen;
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if (sav->spi != htonl(TCP_SIG_SPI)) {
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DPRINTF(("%s: SPI must be TCP_SIG_SPI (0x1000)\n",
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__func__));
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return (EINVAL);
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}
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if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
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DPRINTF(("%s: unsupported authentication algorithm %u\n",
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__func__, sav->alg_auth));
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return (EINVAL);
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}
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if (sav->key_auth == NULL) {
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DPRINTF(("%s: no authentication key present\n", __func__));
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return (EINVAL);
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}
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keylen = _KEYLEN(sav->key_auth);
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if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
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DPRINTF(("%s: invalid key length %u\n", __func__, keylen));
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return (EINVAL);
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}
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return (0);
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}
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/*
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* Paranoia.
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*
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* Called when the SA is deleted.
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*/
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static int
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tcpsignature_zeroize(struct secasvar *sav)
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{
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if (sav->key_auth)
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bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
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sav->tdb_cryptoid = 0;
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sav->tdb_authalgxform = NULL;
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sav->tdb_xform = NULL;
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return (0);
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}
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/*
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* Verify that an input packet passes authentication.
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* Called from the ipsec layer.
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* We do this from within tcp itself, so this routine is just a stub.
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*/
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static int
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tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip,
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int protoff)
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{
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return (0);
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}
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/*
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* Prepend the authentication header.
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* Called from the ipsec layer.
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* We do this from within tcp itself, so this routine is just a stub.
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*/
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static int
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tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr,
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struct mbuf **mp, int skip, int protoff)
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{
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return (EINVAL);
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}
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static struct xformsw tcpsignature_xformsw = {
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XF_TCPSIGNATURE, XFT_AUTH, "TCPMD5",
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tcpsignature_init, tcpsignature_zeroize,
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tcpsignature_input, tcpsignature_output
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};
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static void
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tcpsignature_attach(void)
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{
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xform_register(&tcpsignature_xformsw);
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}
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SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST,
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tcpsignature_attach, NULL)
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