1 /* $FreeBSD: src/sys/netipsec/xform_tcp.c,v 1.6 2008/03/21 18:31:42 bz Exp $ */
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 */
82 static int
83 tcpsignature_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 */
115 static int
116 tcpsignature_zeroize(struct secasvar *sav)
117 {
118
119 if (sav->key_auth)
120 bzero(sav->key_auth->key_data, _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 */
134 static int
135 tcpsignature_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 */
147 static int
148 tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr,
149 struct mbuf **mp, int skip, int protoff)
150 {
151
152 return (EINVAL);
153 }
154
155 static struct xformsw tcpsignature_xformsw = {
156 XF_TCPSIGNATURE, XFT_AUTH, "TCPMD5",
157 tcpsignature_init, tcpsignature_zeroize,
158 tcpsignature_input, tcpsignature_output
159 };
160
161 static void
162 tcpsignature_attach(void)
163 {
164
165 xform_register(&tcpsignature_xformsw);
166 }
167
168 SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST,
169 tcpsignature_attach, NULL);
170
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