xform_tcp.c revision 195699
1/* $FreeBSD: head/sys/netipsec/xform_tcp.c 195699 2009-07-14 22:48:30Z rwatson $ */ 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#include <sys/vimage.h> 43 44#include <netinet/in.h> 45#include <netinet/in_systm.h> 46#include <netinet/ip.h> 47#include <netinet/ip_var.h> 48#include <netinet/tcp.h> 49#include <netinet/tcp_var.h> 50 51#include <net/route.h> 52#include <net/vnet.h> 53 54#include <netipsec/ipsec.h> 55#include <netipsec/xform.h> 56 57#ifdef INET6 58#include <netinet/ip6.h> 59#include <netipsec/ipsec6.h> 60#endif 61 62#include <netipsec/key.h> 63#include <netipsec/key_debug.h> 64 65/* 66 * Initialize a TCP-MD5 SA. Called when the SA is being set up. 67 * 68 * We don't need to set up the tdb prefixed fields, as we don't use the 69 * opencrypto code; we just perform a key length check. 70 * 71 * XXX: Currently we only allow a single 'magic' SPI to be used. 72 * 73 * This allows per-host granularity without affecting the userland 74 * interface, which is a simple socket option toggle switch, 75 * TCP_SIGNATURE_ENABLE. 76 * 77 * To allow per-service granularity requires that we have a means 78 * of mapping port to SPI. The mandated way of doing this is to 79 * use SPD entries to specify packet flows which get the TCP-MD5 80 * treatment, however the code to do this is currently unstable 81 * and unsuitable for production use. 82 * 83 * Therefore we use this compromise in the meantime. 84 */ 85static int 86tcpsignature_init(struct secasvar *sav, struct xformsw *xsp) 87{ 88 int keylen; 89 90 if (sav->spi != htonl(TCP_SIG_SPI)) { 91 DPRINTF(("%s: SPI must be TCP_SIG_SPI (0x1000)\n", 92 __func__)); 93 return (EINVAL); 94 } 95 if (sav->alg_auth != SADB_X_AALG_TCP_MD5) { 96 DPRINTF(("%s: unsupported authentication algorithm %u\n", 97 __func__, sav->alg_auth)); 98 return (EINVAL); 99 } 100 if (sav->key_auth == NULL) { 101 DPRINTF(("%s: no authentication key present\n", __func__)); 102 return (EINVAL); 103 } 104 keylen = _KEYLEN(sav->key_auth); 105 if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) { 106 DPRINTF(("%s: invalid key length %u\n", __func__, keylen)); 107 return (EINVAL); 108 } 109 110 return (0); 111} 112 113/* 114 * Paranoia. 115 * 116 * Called when the SA is deleted. 117 */ 118static int 119tcpsignature_zeroize(struct secasvar *sav) 120{ 121 122 if (sav->key_auth) 123 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 124 125 sav->tdb_cryptoid = 0; 126 sav->tdb_authalgxform = NULL; 127 sav->tdb_xform = NULL; 128 129 return (0); 130} 131 132/* 133 * Verify that an input packet passes authentication. 134 * Called from the ipsec layer. 135 * We do this from within tcp itself, so this routine is just a stub. 136 */ 137static int 138tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip, 139 int protoff) 140{ 141 142 return (0); 143} 144 145/* 146 * Prepend the authentication header. 147 * Called from the ipsec layer. 148 * We do this from within tcp itself, so this routine is just a stub. 149 */ 150static int 151tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr, 152 struct mbuf **mp, int skip, int protoff) 153{ 154 155 return (EINVAL); 156} 157 158static struct xformsw tcpsignature_xformsw = { 159 XF_TCPSIGNATURE, XFT_AUTH, "TCPMD5", 160 tcpsignature_init, tcpsignature_zeroize, 161 tcpsignature_input, tcpsignature_output 162}; 163 164static void 165tcpsignature_attach(void) 166{ 167 168 xform_register(&tcpsignature_xformsw); 169} 170 171SYSINIT(tcpsignature_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, 172 tcpsignature_attach, NULL); 173