ip6_ipsec.c revision 288418
1/*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30#include <sys/cdefs.h> 31__FBSDID("$FreeBSD: head/sys/netinet6/ip6_ipsec.c 288418 2015-09-30 08:16:33Z ae $"); 32 33#include "opt_inet.h" 34#include "opt_sctp.h" 35#include "opt_ipsec.h" 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/kernel.h> 40#include <sys/mac.h> 41#include <sys/malloc.h> 42#include <sys/mbuf.h> 43#include <sys/protosw.h> 44#include <sys/socket.h> 45#include <sys/socketvar.h> 46#include <sys/sysctl.h> 47#include <sys/syslog.h> 48 49#include <net/if.h> 50#include <net/if_var.h> 51#include <net/vnet.h> 52 53#include <netinet/in.h> 54#include <netinet/in_systm.h> 55#include <netinet/in_var.h> 56#include <netinet/ip.h> 57#include <netinet/ip6.h> 58#include <netinet/in_pcb.h> 59#include <netinet/ip_var.h> 60#include <netinet/ip_options.h> 61#ifdef SCTP 62#include <netinet/sctp_crc32.h> 63#endif 64 65#include <machine/in_cksum.h> 66 67#include <netipsec/ipsec.h> 68#include <netipsec/ipsec6.h> 69#include <netipsec/xform.h> 70#include <netipsec/key.h> 71#ifdef IPSEC_DEBUG 72#include <netipsec/key_debug.h> 73#else 74#define KEYDEBUG(lev,arg) 75#endif 76 77#include <netinet6/ip6_ipsec.h> 78#include <netinet6/ip6_var.h> 79 80extern struct protosw inet6sw[]; 81 82#ifdef IPSEC_FILTERTUNNEL 83static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1; 84#else 85static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0; 86#endif 87#define V_ip6_ipsec6_filtertunnel VNET(ip6_ipsec6_filtertunnel) 88 89SYSCTL_DECL(_net_inet6_ipsec6); 90SYSCTL_INT(_net_inet6_ipsec6, OID_AUTO, filtertunnel, 91 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel), 0, 92 "If set filter packets from an IPsec tunnel."); 93 94/* 95 * Check if we have to jump over firewall processing for this packet. 96 * Called from ip6_input(). 97 * 1 = jump over firewall, 0 = packet goes through firewall. 98 */ 99int 100ip6_ipsec_filtertunnel(struct mbuf *m) 101{ 102 103 /* 104 * Bypass packet filtering for packets previously handled by IPsec. 105 */ 106 if (!V_ip6_ipsec6_filtertunnel && 107 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 108 return (1); 109 return (0); 110} 111 112/* 113 * Check if this packet has an active SA and needs to be dropped instead 114 * of forwarded. 115 * Called from ip6_forward(). 116 * 1 = drop packet, 0 = forward packet. 117 */ 118int 119ip6_ipsec_fwd(struct mbuf *m) 120{ 121 122 return (ipsec6_in_reject(m, NULL)); 123} 124 125/* 126 * Check if protocol type doesn't have a further header and do IPSEC 127 * decryption or reject right now. Protocols with further headers get 128 * their IPSEC treatment within the protocol specific processing. 129 * Called from ip6_input(). 130 * 1 = drop packet, 0 = continue processing packet. 131 */ 132int 133ip6_ipsec_input(struct mbuf *m, int nxt) 134{ 135 136 /* 137 * enforce IPsec policy checking if we are seeing last header. 138 * note that we do not visit this with protocols with pcb layer 139 * code - like udp/tcp/raw ip. 140 */ 141 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0) 142 return (ipsec6_in_reject(m, NULL)); 143 return (0); 144} 145 146/* 147 * Called from ip6_output(). 148 * 1 = drop packet, 0 = continue processing packet, 149 * -1 = packet was reinjected and stop processing packet 150 */ 151 152int 153ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *error) 154{ 155 struct secpolicy *sp; 156 157 /* 158 * Check the security policy (SP) for the packet and, if 159 * required, do IPsec-related processing. There are two 160 * cases here; the first time a packet is sent through 161 * it will be untagged and handled by ipsec4_checkpolicy. 162 * If the packet is resubmitted to ip6_output (e.g. after 163 * AH, ESP, etc. processing), there will be a tag to bypass 164 * the lookup and related policy checking. 165 */ 166 if (m_tag_find(*m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) { 167 *error = 0; 168 return (0); 169 } 170 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, error, inp); 171 /* 172 * There are four return cases: 173 * sp != NULL apply IPsec policy 174 * sp == NULL, error == 0 no IPsec handling needed 175 * sp == NULL, error == -EINVAL discard packet w/o error 176 * sp == NULL, error != 0 discard packet, report error 177 */ 178 if (sp != NULL) { 179 /* 180 * Do delayed checksums now because we send before 181 * this is done in the normal processing path. 182 */ 183#ifdef INET 184 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 185 in_delayed_cksum(*m); 186 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 187 } 188#endif 189 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 190 in6_delayed_cksum(*m, (*m)->m_pkthdr.len - sizeof(struct ip6_hdr), 191 sizeof(struct ip6_hdr)); 192 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; 193 } 194#ifdef SCTP 195 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { 196 sctp_delayed_cksum(*m, sizeof(struct ip6_hdr)); 197 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; 198 } 199#endif 200 201 /* NB: callee frees mbuf */ 202 *error = ipsec6_process_packet(*m, sp->req); 203 KEY_FREESP(&sp); 204 if (*error == EJUSTRETURN) { 205 /* 206 * We had a SP with a level of 'use' and no SA. We 207 * will just continue to process the packet without 208 * IPsec processing. 209 */ 210 *error = 0; 211 goto done; 212 } 213 214 /* 215 * Preserve KAME behaviour: ENOENT can be returned 216 * when an SA acquire is in progress. Don't propagate 217 * this to user-level; it confuses applications. 218 * 219 * XXX this will go away when the SADB is redone. 220 */ 221 if (*error == ENOENT) 222 *error = 0; 223 goto reinjected; 224 } else { /* sp == NULL */ 225 if (*error != 0) { 226 /* 227 * Hack: -EINVAL is used to signal that a packet 228 * should be silently discarded. This is typically 229 * because we asked key management for an SA and 230 * it was delayed (e.g. kicked up to IKE). 231 */ 232 if (*error == -EINVAL) 233 *error = 0; 234 goto bad; 235 } 236 /* No IPsec processing for this packet. */ 237 } 238done: 239 return (0); 240reinjected: 241 return (-1); 242bad: 243 if (sp != NULL) 244 KEY_FREESP(&sp); 245 return (1); 246} 247 248#if 0 249/* 250 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 251 * Called from ip_forward(). 252 * Returns MTU suggestion for ICMP needfrag reply. 253 */ 254int 255ip6_ipsec_mtu(struct mbuf *m) 256{ 257 int mtu = 0; 258 /* 259 * If the packet is routed over IPsec tunnel, tell the 260 * originator the tunnel MTU. 261 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 262 * XXX quickhack!!! 263 */ 264#ifdef IPSEC 265 struct secpolicy *sp = NULL; 266 int ipsecerror; 267 int ipsechdr; 268 struct route *ro; 269 sp = ipsec_getpolicybyaddr(m, 270 IPSEC_DIR_OUTBOUND, 271 IP_FORWARDING, 272 &ipsecerror); 273 if (sp != NULL) { 274 /* count IPsec header size */ 275 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 276 277 /* 278 * find the correct route for outer IPv4 279 * header, compute tunnel MTU. 280 */ 281 if (sp->req != NULL && 282 sp->req->sav != NULL && 283 sp->req->sav->sah != NULL) { 284 ro = &sp->req->sav->sah->route_cache.sa_route; 285 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 286 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu : 287 ro->ro_rt->rt_ifp->if_mtu; 288 mtu -= ipsechdr; 289 } 290 } 291 KEY_FREESP(&sp); 292 } 293#endif /* IPSEC */ 294 /* XXX else case missing. */ 295 return mtu; 296} 297#endif 298