1 /* $NetBSD: xform_tcp.c,v 1.25 2022/05/22 11:39:08 riastradh Exp $ */
2 /* $FreeBSD: xform_tcp.c,v 1.1.2.1 2004/02/14 22:24:09 bms Exp $ */
3
4 /*
5 * Copyright (c) 2003 Bruce M. Simpson <bms@spc.org>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 * derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 /*
32 * TCP MD5 Signature Option (RFC2385). Dummy code, everything is handled
33 * in TCP directly.
34 */
35
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: xform_tcp.c,v 1.25 2022/05/22 11:39:08 riastradh Exp $");
38
39 #if defined(_KERNEL_OPT)
40 #include "opt_inet.h"
41 #endif
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/mbuf.h>
46 #include <sys/kernel.h>
47
48 #include <netinet/in.h>
49 #include <netinet/in_systm.h>
50 #include <netinet/ip.h>
51 #include <netinet/ip_var.h>
52 #ifdef TCP_SIGNATURE
53 #include <netinet/tcp_timer.h>
54 #include <netinet/tcp.h>
55 #include <netinet/tcp_var.h>
56 #endif
57
58 #include <netipsec/ipsec.h>
59 #include <netipsec/xform.h>
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 */
84 static int
tcpsignature_init(struct secasvar * sav,const struct xformsw * xsp)85 tcpsignature_init(struct secasvar *sav, const struct xformsw *xsp)
86 {
87 int keylen;
88
89 if (sav->spi != htonl(TCP_SIG_SPI)) {
90 DPRINTF("SPI %x must be TCP_SIG_SPI (0x1000)\n", sav->alg_auth);
91 return EINVAL;
92 }
93 if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
94 DPRINTF("unsupported authentication algorithm %u\n",
95 sav->alg_auth);
96 return EINVAL;
97 }
98 if (sav->key_auth == NULL) {
99 DPRINTF("no authentication key present\n");
100 return EINVAL;
101 }
102 keylen = _KEYLEN(sav->key_auth);
103 if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
104 DPRINTF("invalid key length %u\n", keylen);
105 return EINVAL;
106 }
107
108 return 0;
109 }
110
111 static void
tcpsignature_zeroize(struct secasvar * sav)112 tcpsignature_zeroize(struct secasvar *sav)
113 {
114 if (sav->key_auth) {
115 explicit_memset(_KEYBUF(sav->key_auth), 0,
116 _KEYLEN(sav->key_auth));
117 }
118
119 sav->tdb_cryptoid = 0;
120 sav->tdb_authalgxform = NULL;
121 sav->tdb_xform = NULL;
122 }
123
124 static int
tcpsignature_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)125 tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip,
126 int protoff)
127 {
128 panic("%s: should not have been called", __func__);
129 }
130
131 static int
tcpsignature_output(struct mbuf * m,const struct ipsecrequest * isr,struct secasvar * sav,int skip,int protoff,int flags)132 tcpsignature_output(struct mbuf *m, const struct ipsecrequest *isr,
133 struct secasvar *sav, int skip, int protoff, int flags)
134 {
135 panic("%s: should not have been called", __func__);
136 }
137
138 static struct xformsw tcpsignature_xformsw = {
139 .xf_type = XF_TCPSIGNATURE,
140 .xf_flags = XFT_AUTH,
141 .xf_name = "TCPMD5",
142 .xf_init = tcpsignature_init,
143 .xf_zeroize = tcpsignature_zeroize,
144 .xf_input = tcpsignature_input,
145 .xf_output = tcpsignature_output,
146 .xf_next = NULL,
147 };
148
149 void
tcpsignature_attach(void)150 tcpsignature_attach(void)
151 {
152 xform_register(&tcpsignature_xformsw);
153 }
154