sys/netipsec/xform_tcp.c

   1 /*      $NetBSD: xform_tcp.c,v 1.4 2007/12/11 12:40:10 lukem 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 1.4 2007/12/11 12:40:10 lukem 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