xform_tcp.c revision 139823 
1/*	$FreeBSD: head/sys/netipsec/xform_tcp.c 139823 2005-01-07 01:45:51Z imp $ */
2
3/*-
4 * Copyright (c) 2003 Bruce M. Simpson <bms@spc.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *   notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *   notice, this list of conditions and the following disclaimer in the
14 *   documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *   derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/* TCP MD5 Signature Option (RFC2385) */
31#include "opt_inet.h"
32#include "opt_inet6.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/mbuf.h>
37#include <sys/lock.h>
38#include <sys/socket.h>
39#include <sys/kernel.h>
40#include <sys/protosw.h>
41#include <sys/sysctl.h>
42
43#include <netinet/in.h>
44#include <netinet/in_systm.h>
45#include <netinet/ip.h>
46#include <netinet/ip_var.h>
47#include <netinet/tcp.h>
48#include <netinet/tcp_var.h>
49
50#include <net/route.h>
51#include <netipsec/ipsec.h>
52#include <netipsec/xform.h>
53
54#ifdef INET6
55#include <netinet/ip6.h>
56#include <netipsec/ipsec6.h>
57#endif
58
59#include <netipsec/key.h>
60#include <netipsec/key_debug.h>
61
62/*
63 * Initialize a TCP-MD5 SA. Called when the SA is being set up.
64 *
65 * We don't need to set up the tdb prefixed fields, as we don't use the
66 * opencrypto code; we just perform a key length check.
67 *
68 * XXX: Currently we only allow a single 'magic' SPI to be used.
69 *
70 * This allows per-host granularity without affecting the userland
71 * interface, which is a simple socket option toggle switch,
72 * TCP_SIGNATURE_ENABLE.
73 *
74 * To allow per-service granularity requires that we have a means
75 * of mapping port to SPI. The mandated way of doing this is to
76 * use SPD entries to specify packet flows which get the TCP-MD5
77 * treatment, however the code to do this is currently unstable
78 * and unsuitable for production use.
79 *
80 * Therefore we use this compromise in the meantime.
81 */
82static int
83tcpsignature_init(struct secasvar *sav, struct xformsw *xsp)
84{
85	int keylen;
86
87	if (sav->spi != htonl(TCP_SIG_SPI)) {
88		DPRINTF(("%s: SPI must be TCP_SIG_SPI (0x1000)\n",
89		    __func__));
90		return (EINVAL);
91	}
92	if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
93		DPRINTF(("%s: unsupported authentication algorithm %u\n",
94		    __func__, sav->alg_auth));
95		return (EINVAL);
96	}
97	if (sav->key_auth == NULL) {
98		DPRINTF(("%s: no authentication key present\n", __func__));
99		return (EINVAL);
100	}
101	keylen = _KEYLEN(sav->key_auth);
102	if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
103		DPRINTF(("%s: invalid key length %u\n", __func__, keylen));
104		return (EINVAL);
105	}
106
107	return (0);
108}
109
110/*
111 * Paranoia.
112 *
113 * Called when the SA is deleted.
114 */
115static int
116tcpsignature_zeroize(struct secasvar *sav)
117{
118
119	if (sav->key_auth)
120		bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
121
122	sav->tdb_cryptoid = 0;
123	sav->tdb_authalgxform = NULL;
124	sav->tdb_xform = NULL;
125
126	return (0);
127}
128
129/*
130 * Verify that an input packet passes authentication.
131 * Called from the ipsec layer.
132 * We do this from within tcp itself, so this routine is just a stub.
133 */
134static int
135tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip,
136    int protoff)
137{
138
139	return (0);
140}
141
142/*
143 * Prepend the authentication header.
144 * Called from the ipsec layer.
145 * We do this from within tcp itself, so this routine is just a stub.
146 */
147static int
148tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr,
149    struct mbuf **mp, int skip, int protoff)
150{
151
152	return (EINVAL);
153}
154
155static struct xformsw tcpsignature_xformsw = {
156	XF_TCPSIGNATURE,	XFT_AUTH,		"TCPMD5",
157	tcpsignature_init,	tcpsignature_zeroize,
158	tcpsignature_input,	tcpsignature_output
159};
160
161static void
162tcpsignature_attach(void)
163{
164
165	xform_register(&tcpsignature_xformsw);
166}
167
168SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST,
169    tcpsignature_attach, NULL)
170