ip6_ipsec.c revision 236170
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 236170 2012-05-28 09:30:13Z bz $"); 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 s, error; 132 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 133 s = splnet(); 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 splx(s); 143 /*XXX error stat???*/ 144 DPRINTF(("%s: no SP for forwarding\n", __func__)); /*XXX*/ 145 return 1; 146 } 147 148 /* 149 * Check security policy against packet attributes. 150 */ 151 error = ipsec_in_reject(sp, m); 152 KEY_FREESP(&sp); 153 splx(s); 154 if (error) { 155 V_ip6stat.ip6s_cantforward++; 156 return 1; 157 } 158#endif /* IPSEC */ 159 return 0; 160} 161 162/* 163 * Check if protocol type doesn't have a further header and do IPSEC 164 * decryption or reject right now. Protocols with further headers get 165 * their IPSEC treatment within the protocol specific processing. 166 * Called from ip6_input(). 167 * 1 = drop packet, 0 = continue processing packet. 168 */ 169int 170ip6_ipsec_input(struct mbuf *m, int nxt) 171{ 172#ifdef IPSEC 173 struct m_tag *mtag; 174 struct tdb_ident *tdbi; 175 struct secpolicy *sp; 176 int s, error; 177 /* 178 * enforce IPsec policy checking if we are seeing last header. 179 * note that we do not visit this with protocols with pcb layer 180 * code - like udp/tcp/raw ip. 181 */ 182 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 183 ipsec6_in_reject(m, NULL)) { 184 185 /* 186 * Check if the packet has already had IPsec processing 187 * done. If so, then just pass it along. This tag gets 188 * set during AH, ESP, etc. input handling, before the 189 * packet is returned to the ip input queue for delivery. 190 */ 191 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 192 s = splnet(); 193 if (mtag != NULL) { 194 tdbi = (struct tdb_ident *)(mtag + 1); 195 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 196 } else { 197 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 198 IP_FORWARDING, &error); 199 } 200 if (sp != NULL) { 201 /* 202 * Check security policy against packet attributes. 203 */ 204 error = ipsec_in_reject(sp, m); 205 KEY_FREESP(&sp); 206 } else { 207 /* XXX error stat??? */ 208 error = EINVAL; 209 DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/ 210 return 1; 211 } 212 splx(s); 213 if (error) 214 return 1; 215 } 216#endif /* IPSEC */ 217 return 0; 218} 219 220/* 221 * Called from ip6_output(). 222 * 1 = drop packet, 0 = continue processing packet, 223 * -1 = packet was reinjected and stop processing packet 224 */ 225 226int 227ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 228 struct ifnet **ifp, struct secpolicy **sp) 229{ 230#ifdef IPSEC 231 struct tdb_ident *tdbi; 232 struct m_tag *mtag; 233 /* XXX int s; */ 234 if (sp == NULL) 235 return 1; 236 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 237 if (mtag != NULL) { 238 tdbi = (struct tdb_ident *)(mtag + 1); 239 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 240 if (*sp == NULL) 241 *error = -EINVAL; /* force silent drop */ 242 m_tag_delete(*m, mtag); 243 } else { 244 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 245 error, inp); 246 } 247 248 /* 249 * There are four return cases: 250 * sp != NULL apply IPsec policy 251 * sp == NULL, error == 0 no IPsec handling needed 252 * sp == NULL, error == -EINVAL discard packet w/o error 253 * sp == NULL, error != 0 discard packet, report error 254 */ 255 if (*sp != NULL) { 256 /* Loop detection, check if ipsec processing already done */ 257 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 258 for (mtag = m_tag_first(*m); mtag != NULL; 259 mtag = m_tag_next(*m, mtag)) { 260 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 261 continue; 262 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 263 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 264 continue; 265 /* 266 * Check if policy has an SA associated with it. 267 * This can happen when an SP has yet to acquire 268 * an SA; e.g. on first reference. If it occurs, 269 * then we let ipsec4_process_packet do its thing. 270 */ 271 if ((*sp)->req->sav == NULL) 272 break; 273 tdbi = (struct tdb_ident *)(mtag + 1); 274 if (tdbi->spi == (*sp)->req->sav->spi && 275 tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 276 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 277 sizeof (union sockaddr_union)) == 0) { 278 /* 279 * No IPsec processing is needed, free 280 * reference to SP. 281 * 282 * NB: null pointer to avoid free at 283 * done: below. 284 */ 285 KEY_FREESP(sp), *sp = NULL; 286 /* XXX splx(s); */ 287 goto done; 288 } 289 } 290 291 /* 292 * Do delayed checksums now because we send before 293 * this is done in the normal processing path. 294 * XXX-BZ CSUM_DELAY_DATA_IPV6? 295 */ 296 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 297 ipseclog((LOG_DEBUG, 298 "%s: we do not support IPv4 over IPv6", __func__)); 299#ifdef INET 300 in_delayed_cksum(*m); 301#endif 302 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 303 } 304 305 /* 306 * Preserve KAME behaviour: ENOENT can be returned 307 * when an SA acquire is in progress. Don't propagate 308 * this to user-level; it confuses applications. 309 * 310 * XXX this will go away when the SADB is redone. 311 */ 312 if (*error == ENOENT) 313 *error = 0; 314 goto do_ipsec; 315 } else { /* sp == NULL */ 316 if (*error != 0) { 317 /* 318 * Hack: -EINVAL is used to signal that a packet 319 * should be silently discarded. This is typically 320 * because we asked key management for an SA and 321 * it was delayed (e.g. kicked up to IKE). 322 */ 323 if (*error == -EINVAL) 324 *error = 0; 325 goto bad; 326 } else { 327 /* No IPsec processing for this packet. */ 328 } 329 } 330done: 331 return 0; 332do_ipsec: 333 return -1; 334bad: 335 return 1; 336#endif /* IPSEC */ 337 return 0; 338} 339 340#if 0 341/* 342 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 343 * Called from ip_forward(). 344 * Returns MTU suggestion for ICMP needfrag reply. 345 */ 346int 347ip6_ipsec_mtu(struct mbuf *m) 348{ 349 int mtu = 0; 350 /* 351 * If the packet is routed over IPsec tunnel, tell the 352 * originator the tunnel MTU. 353 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 354 * XXX quickhack!!! 355 */ 356#ifdef IPSEC 357 struct secpolicy *sp = NULL; 358 int ipsecerror; 359 int ipsechdr; 360 struct route *ro; 361 sp = ipsec_getpolicybyaddr(m, 362 IPSEC_DIR_OUTBOUND, 363 IP_FORWARDING, 364 &ipsecerror); 365 if (sp != NULL) { 366 /* count IPsec header size */ 367 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 368 369 /* 370 * find the correct route for outer IPv4 371 * header, compute tunnel MTU. 372 */ 373 if (sp->req != NULL && 374 sp->req->sav != NULL && 375 sp->req->sav->sah != NULL) { 376 ro = &sp->req->sav->sah->route_cache.sa_route; 377 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 378 mtu = 379 ro->ro_rt->rt_rmx.rmx_mtu ? 380 ro->ro_rt->rt_rmx.rmx_mtu : 381 ro->ro_rt->rt_ifp->if_mtu; 382 mtu -= ipsechdr; 383 } 384 } 385 KEY_FREESP(&sp); 386 } 387#endif /* IPSEC */ 388 /* XXX else case missing. */ 389 return mtu; 390} 391#endif 392