ip6_ipsec.c revision 263478
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: stable/10/sys/netinet6/ip6_ipsec.c 263478 2014-03-21 15:15:30Z 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/route.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 62#include <machine/in_cksum.h> 63 64#ifdef IPSEC 65#include <netipsec/ipsec.h> 66#include <netipsec/ipsec6.h> 67#include <netipsec/xform.h> 68#include <netipsec/key.h> 69#ifdef IPSEC_DEBUG 70#include <netipsec/key_debug.h> 71#else 72#define KEYDEBUG(lev,arg) 73#endif 74#endif /*IPSEC*/ 75 76#include <netinet6/ip6_ipsec.h> 77#include <netinet6/ip6_var.h> 78 79extern struct protosw inet6sw[]; 80 81 82#ifdef INET6 83#ifdef IPSEC 84#ifdef IPSEC_FILTERTUNNEL 85static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1; 86#else 87static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0; 88#endif 89#define V_ip6_ipsec6_filtertunnel VNET(ip6_ipsec6_filtertunnel) 90 91SYSCTL_DECL(_net_inet6_ipsec6); 92SYSCTL_VNET_INT(_net_inet6_ipsec6, OID_AUTO, 93 filtertunnel, CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel), 0, 94 "If set filter packets from an IPsec tunnel."); 95#endif /* IPSEC */ 96#endif /* INET6 */ 97 98/* 99 * Check if we have to jump over firewall processing for this packet. 100 * Called from ip6_input(). 101 * 1 = jump over firewall, 0 = packet goes through firewall. 102 */ 103int 104ip6_ipsec_filtertunnel(struct mbuf *m) 105{ 106#ifdef IPSEC 107 108 /* 109 * Bypass packet filtering for packets previously handled by IPsec. 110 */ 111 if (!V_ip6_ipsec6_filtertunnel && 112 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 113 return 1; 114#endif 115 return 0; 116} 117 118/* 119 * Check if this packet has an active SA and needs to be dropped instead 120 * of forwarded. 121 * Called from ip6_input(). 122 * 1 = drop packet, 0 = forward packet. 123 */ 124int 125ip6_ipsec_fwd(struct mbuf *m) 126{ 127#ifdef IPSEC 128 struct m_tag *mtag; 129 struct tdb_ident *tdbi; 130 struct secpolicy *sp; 131 int error; 132 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 133 if (mtag != NULL) { 134 tdbi = (struct tdb_ident *)(mtag + 1); 135 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 136 } else { 137 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 138 IP_FORWARDING, &error); 139 } 140 if (sp == NULL) { /* NB: can happen if error */ 141 /*XXX error stat???*/ 142 DPRINTF(("%s: no SP for forwarding\n", __func__)); /*XXX*/ 143 return 1; 144 } 145 146 /* 147 * Check security policy against packet attributes. 148 */ 149 error = ipsec_in_reject(sp, m); 150 KEY_FREESP(&sp); 151 if (error) { 152 IP6STAT_INC(ip6s_cantforward); 153 return 1; 154 } 155#endif /* IPSEC */ 156 return 0; 157} 158 159/* 160 * Check if protocol type doesn't have a further header and do IPSEC 161 * decryption or reject right now. Protocols with further headers get 162 * their IPSEC treatment within the protocol specific processing. 163 * Called from ip6_input(). 164 * 1 = drop packet, 0 = continue processing packet. 165 */ 166int 167ip6_ipsec_input(struct mbuf *m, int nxt) 168{ 169#ifdef IPSEC 170 struct m_tag *mtag; 171 struct tdb_ident *tdbi; 172 struct secpolicy *sp; 173 int error; 174 /* 175 * enforce IPsec policy checking if we are seeing last header. 176 * note that we do not visit this with protocols with pcb layer 177 * code - like udp/tcp/raw ip. 178 */ 179 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 180 ipsec6_in_reject(m, NULL)) { 181 182 /* 183 * Check if the packet has already had IPsec processing 184 * done. If so, then just pass it along. This tag gets 185 * set during AH, ESP, etc. input handling, before the 186 * packet is returned to the ip input queue for delivery. 187 */ 188 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 189 if (mtag != NULL) { 190 tdbi = (struct tdb_ident *)(mtag + 1); 191 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 192 } else { 193 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 194 IP_FORWARDING, &error); 195 } 196 if (sp != NULL) { 197 /* 198 * Check security policy against packet attributes. 199 */ 200 error = ipsec_in_reject(sp, m); 201 KEY_FREESP(&sp); 202 } else { 203 /* XXX error stat??? */ 204 error = EINVAL; 205 DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/ 206 return 1; 207 } 208 if (error) 209 return 1; 210 } 211#endif /* IPSEC */ 212 return 0; 213} 214 215/* 216 * Called from ip6_output(). 217 * 1 = drop packet, 0 = continue processing packet, 218 * -1 = packet was reinjected and stop processing packet 219 */ 220 221int 222ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 223 struct ifnet **ifp, struct secpolicy **sp) 224{ 225#ifdef IPSEC 226 struct tdb_ident *tdbi; 227 struct m_tag *mtag; 228 /* XXX int s; */ 229 if (sp == NULL) 230 return 1; 231 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 232 if (mtag != NULL) { 233 tdbi = (struct tdb_ident *)(mtag + 1); 234 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 235 if (*sp == NULL) 236 *error = -EINVAL; /* force silent drop */ 237 m_tag_delete(*m, mtag); 238 } else { 239 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 240 error, inp); 241 } 242 243 /* 244 * There are four return cases: 245 * sp != NULL apply IPsec policy 246 * sp == NULL, error == 0 no IPsec handling needed 247 * sp == NULL, error == -EINVAL discard packet w/o error 248 * sp == NULL, error != 0 discard packet, report error 249 */ 250 if (*sp != NULL) { 251 /* Loop detection, check if ipsec processing already done */ 252 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 253 for (mtag = m_tag_first(*m); mtag != NULL; 254 mtag = m_tag_next(*m, mtag)) { 255 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 256 continue; 257 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 258 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 259 continue; 260 /* 261 * Check if policy has no SA associated with it. 262 * This can happen when an SP has yet to acquire 263 * an SA; e.g. on first reference. If it occurs, 264 * then we let ipsec4_process_packet do its thing. 265 */ 266 if ((*sp)->req->sav == NULL) 267 break; 268 tdbi = (struct tdb_ident *)(mtag + 1); 269 if (tdbi->spi == (*sp)->req->sav->spi && 270 tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 271 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 272 sizeof (union sockaddr_union)) == 0) { 273 /* 274 * No IPsec processing is needed, free 275 * reference to SP. 276 * 277 * NB: null pointer to avoid free at 278 * done: below. 279 */ 280 KEY_FREESP(sp), *sp = NULL; 281 goto done; 282 } 283 } 284 285 /* 286 * Do delayed checksums now because we send before 287 * this is done in the normal processing path. 288 * For IPv6 we do delayed checksums in ip6_output.c. 289 */ 290#ifdef INET 291 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 292 ipseclog((LOG_DEBUG, 293 "%s: we do not support IPv4 over IPv6", __func__)); 294 in_delayed_cksum(*m); 295 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 296 } 297#endif 298 299 /* 300 * Preserve KAME behaviour: ENOENT can be returned 301 * when an SA acquire is in progress. Don't propagate 302 * this to user-level; it confuses applications. 303 * 304 * XXX this will go away when the SADB is redone. 305 */ 306 if (*error == ENOENT) 307 *error = 0; 308 goto do_ipsec; 309 } else { /* sp == NULL */ 310 if (*error != 0) { 311 /* 312 * Hack: -EINVAL is used to signal that a packet 313 * should be silently discarded. This is typically 314 * because we asked key management for an SA and 315 * it was delayed (e.g. kicked up to IKE). 316 */ 317 if (*error == -EINVAL) 318 *error = 0; 319 goto bad; 320 } else { 321 /* No IPsec processing for this packet. */ 322 } 323 } 324done: 325 return 0; 326do_ipsec: 327 return -1; 328bad: 329 return 1; 330#endif /* IPSEC */ 331 return 0; 332} 333 334#if 0 335/* 336 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 337 * Called from ip_forward(). 338 * Returns MTU suggestion for ICMP needfrag reply. 339 */ 340int 341ip6_ipsec_mtu(struct mbuf *m) 342{ 343 int mtu = 0; 344 /* 345 * If the packet is routed over IPsec tunnel, tell the 346 * originator the tunnel MTU. 347 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 348 * XXX quickhack!!! 349 */ 350#ifdef IPSEC 351 struct secpolicy *sp = NULL; 352 int ipsecerror; 353 int ipsechdr; 354 struct route *ro; 355 sp = ipsec_getpolicybyaddr(m, 356 IPSEC_DIR_OUTBOUND, 357 IP_FORWARDING, 358 &ipsecerror); 359 if (sp != NULL) { 360 /* count IPsec header size */ 361 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 362 363 /* 364 * find the correct route for outer IPv4 365 * header, compute tunnel MTU. 366 */ 367 if (sp->req != NULL && 368 sp->req->sav != NULL && 369 sp->req->sav->sah != NULL) { 370 ro = &sp->req->sav->sah->route_cache.sa_route; 371 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 372 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu : 373 ro->ro_rt->rt_ifp->if_mtu; 374 mtu -= ipsechdr; 375 } 376 } 377 KEY_FREESP(&sp); 378 } 379#endif /* IPSEC */ 380 /* XXX else case missing. */ 381 return mtu; 382} 383#endif 384