ip6_ipsec.c revision 262763
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 262763 2014-03-05 01:17:47Z glebius $"); 32 33#include "opt_inet.h" 34#include "opt_inet6.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/route.h> 52#include <net/vnet.h> 53 54#include <netinet/in.h> 55#include <netinet/in_systm.h> 56#include <netinet/in_var.h> 57#include <netinet/ip.h> 58#include <netinet/ip6.h> 59#include <netinet/in_pcb.h> 60#include <netinet/ip_var.h> 61#include <netinet/ip_options.h> 62 63#include <machine/in_cksum.h> 64 65#ifdef IPSEC 66#include <netipsec/ipsec.h> 67#include <netipsec/ipsec6.h> 68#include <netipsec/xform.h> 69#include <netipsec/key.h> 70#ifdef IPSEC_DEBUG 71#include <netipsec/key_debug.h> 72#else 73#define KEYDEBUG(lev,arg) 74#endif 75#endif /*IPSEC*/ 76 77#include <netinet6/ip6_ipsec.h> 78#include <netinet6/ip6_var.h> 79 80extern struct protosw inet6sw[]; 81 82 83#ifdef INET6 84#ifdef IPSEC 85#ifdef IPSEC_FILTERTUNNEL 86static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1; 87#else 88static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0; 89#endif 90#define V_ip6_ipsec6_filtertunnel VNET(ip6_ipsec6_filtertunnel) 91 92SYSCTL_DECL(_net_inet6_ipsec6); 93SYSCTL_VNET_INT(_net_inet6_ipsec6, OID_AUTO, 94 filtertunnel, CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel), 0, 95 "If set filter packets from an IPsec tunnel."); 96#endif /* IPSEC */ 97#endif /* INET6 */ 98 99/* 100 * Check if we have to jump over firewall processing for this packet. 101 * Called from ip6_input(). 102 * 1 = jump over firewall, 0 = packet goes through firewall. 103 */ 104int 105ip6_ipsec_filtertunnel(struct mbuf *m) 106{ 107#ifdef IPSEC 108 109 /* 110 * Bypass packet filtering for packets previously handled by IPsec. 111 */ 112 if (!V_ip6_ipsec6_filtertunnel && 113 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 114 return 1; 115#endif 116 return 0; 117} 118 119/* 120 * Check if this packet has an active SA and needs to be dropped instead 121 * of forwarded. 122 * Called from ip6_input(). 123 * 1 = drop packet, 0 = forward packet. 124 */ 125int 126ip6_ipsec_fwd(struct mbuf *m) 127{ 128#ifdef IPSEC 129 struct m_tag *mtag; 130 struct tdb_ident *tdbi; 131 struct secpolicy *sp; 132 int error; 133 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 134 if (mtag != NULL) { 135 tdbi = (struct tdb_ident *)(mtag + 1); 136 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 137 } else { 138 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 139 IP_FORWARDING, &error); 140 } 141 if (sp == NULL) { /* NB: can happen if error */ 142 /*XXX error stat???*/ 143 DPRINTF(("%s: no SP for forwarding\n", __func__)); /*XXX*/ 144 return 1; 145 } 146 147 /* 148 * Check security policy against packet attributes. 149 */ 150 error = ipsec_in_reject(sp, m); 151 KEY_FREESP(&sp); 152 if (error) { 153 IP6STAT_INC(ip6s_cantforward); 154 return 1; 155 } 156#endif /* IPSEC */ 157 return 0; 158} 159 160/* 161 * Check if protocol type doesn't have a further header and do IPSEC 162 * decryption or reject right now. Protocols with further headers get 163 * their IPSEC treatment within the protocol specific processing. 164 * Called from ip6_input(). 165 * 1 = drop packet, 0 = continue processing packet. 166 */ 167int 168ip6_ipsec_input(struct mbuf *m, int nxt) 169{ 170#ifdef IPSEC 171 struct m_tag *mtag; 172 struct tdb_ident *tdbi; 173 struct secpolicy *sp; 174 int error; 175 /* 176 * enforce IPsec policy checking if we are seeing last header. 177 * note that we do not visit this with protocols with pcb layer 178 * code - like udp/tcp/raw ip. 179 */ 180 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 181 ipsec6_in_reject(m, NULL)) { 182 183 /* 184 * Check if the packet has already had IPsec processing 185 * done. If so, then just pass it along. This tag gets 186 * set during AH, ESP, etc. input handling, before the 187 * packet is returned to the ip input queue for delivery. 188 */ 189 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 190 if (mtag != NULL) { 191 tdbi = (struct tdb_ident *)(mtag + 1); 192 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 193 } else { 194 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 195 IP_FORWARDING, &error); 196 } 197 if (sp != NULL) { 198 /* 199 * Check security policy against packet attributes. 200 */ 201 error = ipsec_in_reject(sp, m); 202 KEY_FREESP(&sp); 203 } else { 204 /* XXX error stat??? */ 205 error = EINVAL; 206 DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/ 207 return 1; 208 } 209 if (error) 210 return 1; 211 } 212#endif /* IPSEC */ 213 return 0; 214} 215 216/* 217 * Called from ip6_output(). 218 * 1 = drop packet, 0 = continue processing packet, 219 * -1 = packet was reinjected and stop processing packet 220 */ 221 222int 223ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 224 struct ifnet **ifp, struct secpolicy **sp) 225{ 226#ifdef IPSEC 227 struct tdb_ident *tdbi; 228 struct m_tag *mtag; 229 /* XXX int s; */ 230 if (sp == NULL) 231 return 1; 232 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 233 if (mtag != NULL) { 234 tdbi = (struct tdb_ident *)(mtag + 1); 235 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 236 if (*sp == NULL) 237 *error = -EINVAL; /* force silent drop */ 238 m_tag_delete(*m, mtag); 239 } else { 240 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 241 error, inp); 242 } 243 244 /* 245 * There are four return cases: 246 * sp != NULL apply IPsec policy 247 * sp == NULL, error == 0 no IPsec handling needed 248 * sp == NULL, error == -EINVAL discard packet w/o error 249 * sp == NULL, error != 0 discard packet, report error 250 */ 251 if (*sp != NULL) { 252 /* Loop detection, check if ipsec processing already done */ 253 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 254 for (mtag = m_tag_first(*m); mtag != NULL; 255 mtag = m_tag_next(*m, mtag)) { 256 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 257 continue; 258 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 259 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 260 continue; 261 /* 262 * Check if policy has no SA associated with it. 263 * This can happen when an SP has yet to acquire 264 * an SA; e.g. on first reference. If it occurs, 265 * then we let ipsec4_process_packet do its thing. 266 */ 267 if ((*sp)->req->sav == NULL) 268 break; 269 tdbi = (struct tdb_ident *)(mtag + 1); 270 if (tdbi->spi == (*sp)->req->sav->spi && 271 tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 272 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 273 sizeof (union sockaddr_union)) == 0) { 274 /* 275 * No IPsec processing is needed, free 276 * reference to SP. 277 * 278 * NB: null pointer to avoid free at 279 * done: below. 280 */ 281 KEY_FREESP(sp), *sp = NULL; 282 goto done; 283 } 284 } 285 286 /* 287 * Do delayed checksums now because we send before 288 * this is done in the normal processing path. 289 * For IPv6 we do delayed checksums in ip6_output.c. 290 */ 291#ifdef INET 292 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 293 ipseclog((LOG_DEBUG, 294 "%s: we do not support IPv4 over IPv6", __func__)); 295 in_delayed_cksum(*m); 296 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 297 } 298#endif 299 300 /* 301 * Preserve KAME behaviour: ENOENT can be returned 302 * when an SA acquire is in progress. Don't propagate 303 * this to user-level; it confuses applications. 304 * 305 * XXX this will go away when the SADB is redone. 306 */ 307 if (*error == ENOENT) 308 *error = 0; 309 goto do_ipsec; 310 } else { /* sp == NULL */ 311 if (*error != 0) { 312 /* 313 * Hack: -EINVAL is used to signal that a packet 314 * should be silently discarded. This is typically 315 * because we asked key management for an SA and 316 * it was delayed (e.g. kicked up to IKE). 317 */ 318 if (*error == -EINVAL) 319 *error = 0; 320 goto bad; 321 } else { 322 /* No IPsec processing for this packet. */ 323 } 324 } 325done: 326 return 0; 327do_ipsec: 328 return -1; 329bad: 330 return 1; 331#endif /* IPSEC */ 332 return 0; 333} 334 335#if 0 336/* 337 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 338 * Called from ip_forward(). 339 * Returns MTU suggestion for ICMP needfrag reply. 340 */ 341int 342ip6_ipsec_mtu(struct mbuf *m) 343{ 344 int mtu = 0; 345 /* 346 * If the packet is routed over IPsec tunnel, tell the 347 * originator the tunnel MTU. 348 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 349 * XXX quickhack!!! 350 */ 351#ifdef IPSEC 352 struct secpolicy *sp = NULL; 353 int ipsecerror; 354 int ipsechdr; 355 struct route *ro; 356 sp = ipsec_getpolicybyaddr(m, 357 IPSEC_DIR_OUTBOUND, 358 IP_FORWARDING, 359 &ipsecerror); 360 if (sp != NULL) { 361 /* count IPsec header size */ 362 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 363 364 /* 365 * find the correct route for outer IPv4 366 * header, compute tunnel MTU. 367 */ 368 if (sp->req != NULL && 369 sp->req->sav != NULL && 370 sp->req->sav->sah != NULL) { 371 ro = &sp->req->sav->sah->route_cache.sa_route; 372 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 373 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu : 374 ro->ro_rt->rt_ifp->if_mtu; 375 mtu -= ipsechdr; 376 } 377 } 378 KEY_FREESP(&sp); 379 } 380#endif /* IPSEC */ 381 /* XXX else case missing. */ 382 return mtu; 383} 384#endif 385