xref: /freebsd/sys/netipsec/xform_tcp.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 <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