xform_tcp.c revision 1.19
1 /* $NetBSD: xform_tcp.c,v 1.19 2018/05/07 09:16:46 maxv 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 (at) 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 1.19 2018/05/07 09:16:46 maxv Exp $"); 35 36 #if defined(_KERNEL_OPT) 37 #include "opt_inet.h" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/mbuf.h> 43 #include <sys/lock.h> 44 #include <sys/socket.h> 45 #include <sys/kernel.h> 46 #include <sys/protosw.h> 47 #include <sys/sysctl.h> 48 49 #include <netinet/in.h> 50 #include <netinet/in_systm.h> 51 #include <netinet/ip.h> 52 #include <netinet/ip_var.h> 53 #include <netinet/tcp_timer.h> 54 #include <netinet/tcp.h> 55 #include <netinet/tcp_var.h> 56 57 #include <net/route.h> 58 #include <netipsec/ipsec.h> 59 #include <netipsec/xform.h> 60 61 #ifdef INET6 62 #include <netinet/ip6.h> 63 #include <netipsec/ipsec6.h> 64 #endif 65 66 #include <netipsec/key.h> 67 #include <netipsec/key_debug.h> 68 69 /* 70 * Initialize a TCP-MD5 SA. Called when the SA is being set up. 71 * 72 * We don't need to set up the tdb prefixed fields, as we don't use the 73 * opencrypto code; we just perform a key length check. 74 * 75 * XXX: Currently we only allow a single 'magic' SPI to be used. 76 * 77 * This allows per-host granularity without affecting the userland 78 * interface, which is a simple socket option toggle switch, 79 * TCP_SIGNATURE_ENABLE. 80 * 81 * To allow per-service granularity requires that we have a means 82 * of mapping port to SPI. The mandated way of doing this is to 83 * use SPD entries to specify packet flows which get the TCP-MD5 84 * treatment, however the code to do this is currently unstable 85 * and unsuitable for production use. 86 * 87 * Therefore we use this compromise in the meantime. 88 */ 89 static int 90 tcpsignature_init(struct secasvar *sav, const struct xformsw *xsp) 91 { 92 int keylen; 93 94 if (sav->spi != htonl(TCP_SIG_SPI)) { 95 DPRINTF(("%s: SPI %x must be TCP_SIG_SPI (0x1000)\n", 96 __func__, sav->alg_auth)); 97 return (EINVAL); 98 } 99 if (sav->alg_auth != SADB_X_AALG_TCP_MD5) { 100 DPRINTF(("%s: unsupported authentication algorithm %u\n", 101 __func__, sav->alg_auth)); 102 return (EINVAL); 103 } 104 if (sav->key_auth == NULL) { 105 DPRINTF(("%s: no authentication key present\n", __func__)); 106 return (EINVAL); 107 } 108 keylen = _KEYLEN(sav->key_auth); 109 if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) { 110 DPRINTF(("%s: invalid key length %u\n", __func__, keylen)); 111 return (EINVAL); 112 } 113 114 return (0); 115 } 116 117 /* 118 * Paranoia. 119 * 120 * Called when the SA is deleted. 121 */ 122 static int 123 tcpsignature_zeroize(struct secasvar *sav) 124 { 125 126 if (sav->key_auth) { 127 explicit_memset(_KEYBUF(sav->key_auth), 0, 128 _KEYLEN(sav->key_auth)); 129 } 130 131 sav->tdb_cryptoid = 0; 132 sav->tdb_authalgxform = NULL; 133 sav->tdb_xform = NULL; 134 135 return (0); 136 } 137 138 /* 139 * Verify that an input packet passes authentication. 140 * Called from the ipsec layer. 141 * We do this from within tcp itself, so this routine is just a stub. 142 */ 143 static int 144 tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip, 145 int protoff) 146 { 147 /* XXX m_freem(m)? */ 148 return (0); 149 } 150 151 /* 152 * Prepend the authentication header. 153 * Called from the ipsec layer. 154 * We do this from within tcp itself, so this routine is just a stub. 155 */ 156 static int 157 tcpsignature_output(struct mbuf *m, const struct ipsecrequest *isr, 158 struct secasvar *sav, int skip, int protoff) 159 { 160 161 return (EINVAL); 162 } 163 164 static struct xformsw tcpsignature_xformsw = { 165 .xf_type = XF_TCPSIGNATURE, 166 .xf_flags = XFT_AUTH, 167 .xf_name = "TCPMD5", 168 .xf_init = tcpsignature_init, 169 .xf_zeroize = tcpsignature_zeroize, 170 .xf_input = tcpsignature_input, 171 .xf_output = tcpsignature_output, 172 .xf_next = NULL, 173 }; 174 175 void 176 tcpsignature_attach(void) 177 { 178 179 xform_register(&tcpsignature_xformsw); 180 } 181
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