1/*	$FreeBSD$ */
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 <net/vnet.h>
52
53#include <netipsec/ipsec.h>
54#include <netipsec/xform.h>
55
56#ifdef INET6
57#include <netinet/ip6.h>
58#include <netipsec/ipsec6.h>
59#endif
60
61#include <netipsec/key.h>
62#include <netipsec/key_debug.h>
63
64/*
65 * Initialize a TCP-MD5 SA. Called when the SA is being set up.
66 *
67 * We don't need to set up the tdb prefixed fields, as we don't use the
68 * opencrypto code; we just perform a key length check.
69 *
70 * XXX: Currently we only allow a single 'magic' SPI to be used.
71 *
72 * This allows per-host granularity without affecting the userland
73 * interface, which is a simple socket option toggle switch,
74 * TCP_SIGNATURE_ENABLE.
75 *
76 * To allow per-service granularity requires that we have a means
77 * of mapping port to SPI. The mandated way of doing this is to
78 * use SPD entries to specify packet flows which get the TCP-MD5
79 * treatment, however the code to do this is currently unstable
80 * and unsuitable for production use.
81 *
82 * Therefore we use this compromise in the meantime.
83 */
84static int
85tcpsignature_init(struct secasvar *sav, struct xformsw *xsp)
86{
87	int keylen;
88
89	if (sav->spi != htonl(TCP_SIG_SPI)) {
90		DPRINTF(("%s: SPI must be TCP_SIG_SPI (0x1000)\n",
91		    __func__));
92		return (EINVAL);
93	}
94	if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
95		DPRINTF(("%s: unsupported authentication algorithm %u\n",
96		    __func__, sav->alg_auth));
97		return (EINVAL);
98	}
99	if (sav->key_auth == NULL) {
100		DPRINTF(("%s: no authentication key present\n", __func__));
101		return (EINVAL);
102	}
103	keylen = _KEYLEN(sav->key_auth);
104	if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
105		DPRINTF(("%s: invalid key length %u\n", __func__, keylen));
106		return (EINVAL);
107	}
108
109	return (0);
110}
111
112/*
113 * Paranoia.
114 *
115 * Called when the SA is deleted.
116 */
117static int
118tcpsignature_zeroize(struct secasvar *sav)
119{
120
121	if (sav->key_auth)
122		bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
123
124	sav->tdb_cryptoid = 0;
125	sav->tdb_authalgxform = NULL;
126	sav->tdb_xform = NULL;
127
128	return (0);
129}
130
131/*
132 * Verify that an input packet passes authentication.
133 * Called from the ipsec layer.
134 * We do this from within tcp itself, so this routine is just a stub.
135 */
136static int
137tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip,
138    int protoff)
139{
140
141	return (0);
142}
143
144/*
145 * Prepend the authentication header.
146 * Called from the ipsec layer.
147 * We do this from within tcp itself, so this routine is just a stub.
148 */
149static int
150tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr,
151    struct mbuf **mp, int skip, int protoff)
152{
153
154	return (EINVAL);
155}
156
157static struct xformsw tcpsignature_xformsw = {
158	XF_TCPSIGNATURE,	XFT_AUTH,		"TCPMD5",
159	tcpsignature_init,	tcpsignature_zeroize,
160	tcpsignature_input,	tcpsignature_output
161};
162
163static void
164tcpsignature_attach(void)
165{
166
167	xform_register(&tcpsignature_xformsw);
168}
169
170SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST,
171    tcpsignature_attach, NULL);
172