1 /* $NetBSD: xform_tcp.c,v 1.5 2009/03/18 16:00:23 cegger Exp $ */ 2 /* $FreeBSD: sys/netipsec/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 /* TCP MD5 Signature Option (RFC2385) */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: xform_tcp.c,v 1.5 2009/03/18 16:00:23 cegger Exp $"); 35 36 #include "opt_inet.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/mbuf.h> 41 #include <sys/lock.h> 42 #include <sys/socket.h> 43 #include <sys/kernel.h> 44 #include <sys/protosw.h> 45 #include <sys/sysctl.h> 46 47 #include <netinet/in.h> 48 #include <netinet/in_systm.h> 49 #include <netinet/ip.h> 50 #include <netinet/ip_var.h> 51 #include <netinet/tcp_timer.h> 52 #include <netinet/tcp.h> 53 #include <netinet/tcp_var.h> 54 55 #include <net/route.h> 56 #include <netipsec/ipsec.h> 57 #include <netipsec/xform.h> 58 59 #ifdef INET6 60 #include <netinet/ip6.h> 61 #include <netipsec/ipsec6.h> 62 #endif 63 64 #include <netipsec/key.h> 65 #include <netipsec/key_debug.h> 66 67 /* 68 * Initialize a TCP-MD5 SA. Called when the SA is being set up. 69 * 70 * We don't need to set up the tdb prefixed fields, as we don't use the 71 * opencrypto code; we just perform a key length check. 72 * 73 * XXX: Currently we only allow a single 'magic' SPI to be used. 74 * 75 * This allows per-host granularity without affecting the userland 76 * interface, which is a simple socket option toggle switch, 77 * TCP_SIGNATURE_ENABLE. 78 * 79 * To allow per-service granularity requires that we have a means 80 * of mapping port to SPI. The mandated way of doing this is to 81 * use SPD entries to specify packet flows which get the TCP-MD5 82 * treatment, however the code to do this is currently unstable 83 * and unsuitable for production use. 84 * 85 * Therefore we use this compromise in the meantime. 86 */ 87 static int 88 tcpsignature_init(struct secasvar *sav, struct xformsw *xsp) 89 { 90 int keylen; 91 92 if (sav->spi != htonl(TCP_SIG_SPI)) { 93 DPRINTF(("%s: SPI %x must be TCP_SIG_SPI (0x1000)\n", 94 __func__, sav->alg_auth)); 95 return (EINVAL); 96 } 97 if (sav->alg_auth != SADB_X_AALG_TCP_MD5) { 98 DPRINTF(("%s: unsupported authentication algorithm %u\n", 99 __func__, sav->alg_auth)); 100 return (EINVAL); 101 } 102 if (sav->key_auth == NULL) { 103 DPRINTF(("%s: no authentication key present\n", __func__)); 104 return (EINVAL); 105 } 106 keylen = _KEYLEN(sav->key_auth); 107 if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) { 108 DPRINTF(("%s: invalid key length %u\n", __func__, keylen)); 109 return (EINVAL); 110 } 111 112 return (0); 113 } 114 115 /* 116 * Paranoia. 117 * 118 * Called when the SA is deleted. 119 */ 120 static int 121 tcpsignature_zeroize(struct secasvar *sav) 122 { 123 124 if (sav->key_auth) 125 memset(_KEYBUF(sav->key_auth), 0, _KEYLEN(sav->key_auth)); 126 127 sav->tdb_cryptoid = 0; 128 sav->tdb_authalgxform = NULL; 129 sav->tdb_xform = NULL; 130 131 return (0); 132 } 133 134 /* 135 * Verify that an input packet passes authentication. 136 * Called from the ipsec layer. 137 * We do this from within tcp itself, so this routine is just a stub. 138 */ 139 static int 140 tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip, 141 int protoff) 142 { 143 144 return (0); 145 } 146 147 /* 148 * Prepend the authentication header. 149 * Called from the ipsec layer. 150 * We do this from within tcp itself, so this routine is just a stub. 151 */ 152 static int 153 tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr, 154 struct mbuf **mp, int skip, int protoff) 155 { 156 157 return (EINVAL); 158 } 159 160 static struct xformsw tcpsignature_xformsw = { 161 XF_TCPSIGNATURE, XFT_AUTH, "TCPMD5", 162 tcpsignature_init, tcpsignature_zeroize, 163 tcpsignature_input, tcpsignature_output 164 }; 165 166 INITFN void 167 tcpsignature_attach(void) 168 { 169 170 xform_register(&tcpsignature_xformsw); 171 } 172 173 #ifdef __FreeBSD__ 174 SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, 175 tcpsignature_attach, NULL) 176 177 #endif 178 179