ip6_ipsec.c revision 195699
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 195699 2009-07-14 22:48:30Z rwatson $"); 32 33#include "opt_inet6.h" 34#include "opt_ipsec.h" 35 36#include <sys/param.h> 37#include <sys/systm.h> 38#include <sys/kernel.h> 39#include <sys/mac.h> 40#include <sys/malloc.h> 41#include <sys/mbuf.h> 42#include <sys/protosw.h> 43#include <sys/socket.h> 44#include <sys/socketvar.h> 45#include <sys/sysctl.h> 46#include <sys/vimage.h> 47 48#include <net/if.h> 49#include <net/route.h> 50#include <net/vnet.h> 51 52#include <netinet/in.h> 53#include <netinet/in_systm.h> 54#include <netinet/in_var.h> 55#include <netinet/ip.h> 56#include <netinet/ip6.h> 57#include <netinet/in_pcb.h> 58#include <netinet/ip_var.h> 59#include <netinet/ip_options.h> 60 61#include <machine/in_cksum.h> 62 63#ifdef IPSEC 64#include <netipsec/ipsec.h> 65#include <netipsec/ipsec6.h> 66#include <netipsec/xform.h> 67#include <netipsec/key.h> 68#ifdef IPSEC_DEBUG 69#include <netipsec/key_debug.h> 70#else 71#define KEYDEBUG(lev,arg) 72#endif 73#endif /*IPSEC*/ 74 75#include <netinet6/ip6_ipsec.h> 76#include <netinet6/ip6_var.h> 77 78extern struct protosw inet6sw[]; 79 80 81#ifdef INET6 82#ifdef IPSEC 83#ifdef IPSEC_FILTERTUNNEL 84static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1; 85#else 86static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0; 87#endif 88#define V_ip6_ipsec6_filtertunnel VNET_GET(ip6_ipsec6_filtertunnel) 89 90SYSCTL_DECL(_net_inet6_ipsec6); 91SYSCTL_VNET_INT(_net_inet6_ipsec6, OID_AUTO, 92 filtertunnel, CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel), 0, 93 "If set filter packets from an IPsec tunnel."); 94#endif /* IPSEC */ 95#endif /* INET6 */ 96 97/* 98 * Check if we have to jump over firewall processing for this packet. 99 * Called from ip_input(). 100 * 1 = jump over firewall, 0 = packet goes through firewall. 101 */ 102int 103ip6_ipsec_filtertunnel(struct mbuf *m) 104{ 105#if defined(IPSEC) 106 107 /* 108 * Bypass packet filtering for packets from a tunnel. 109 */ 110 if (!V_ip6_ipsec6_filtertunnel && 111 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 112 return 1; 113#endif 114 return 0; 115} 116 117/* 118 * Check if this packet has an active SA and needs to be dropped instead 119 * of forwarded. 120 * Called from ip_input(). 121 * 1 = drop packet, 0 = forward packet. 122 */ 123int 124ip6_ipsec_fwd(struct mbuf *m) 125{ 126#ifdef IPSEC 127 struct m_tag *mtag; 128 struct tdb_ident *tdbi; 129 struct secpolicy *sp; 130 int s, error; 131 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 132 s = splnet(); 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 splx(s); 142 /*XXX error stat???*/ 143 DPRINTF(("ip_input: no SP for forwarding\n")); /*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 splx(s); 153 if (error) { 154 V_ip6stat.ip6s_cantforward++; 155 return 1; 156 } 157#endif /* IPSEC */ 158 return 0; 159} 160 161/* 162 * Check if protocol type doesn't have a further header and do IPSEC 163 * decryption or reject right now. Protocols with further headers get 164 * their IPSEC treatment within the protocol specific processing. 165 * Called from ip_input(). 166 * 1 = drop packet, 0 = continue processing packet. 167 */ 168int 169ip6_ipsec_input(struct mbuf *m, int nxt) 170{ 171#ifdef IPSEC 172 struct m_tag *mtag; 173 struct tdb_ident *tdbi; 174 struct secpolicy *sp; 175 int s, error; 176 /* 177 * enforce IPsec policy checking if we are seeing last header. 178 * note that we do not visit this with protocols with pcb layer 179 * code - like udp/tcp/raw ip. 180 */ 181 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 182 ipsec6_in_reject(m, NULL)) { 183 184 /* 185 * Check if the packet has already had IPsec processing 186 * done. If so, then just pass it along. This tag gets 187 * set during AH, ESP, etc. input handling, before the 188 * packet is returned to the ip input queue for delivery. 189 */ 190 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 191 s = splnet(); 192 if (mtag != NULL) { 193 tdbi = (struct tdb_ident *)(mtag + 1); 194 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 195 } else { 196 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 197 IP_FORWARDING, &error); 198 } 199 if (sp != NULL) { 200 /* 201 * Check security policy against packet attributes. 202 */ 203 error = ipsec_in_reject(sp, m); 204 KEY_FREESP(&sp); 205 } else { 206 /* XXX error stat??? */ 207 error = EINVAL; 208 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 209 return 1; 210 } 211 splx(s); 212 if (error) 213 return 1; 214 } 215#endif /* IPSEC */ 216 return 0; 217} 218 219/* 220 * Called from ip6_output(). 221 * 1 = drop packet, 0 = continue processing packet, 222 * -1 = packet was reinjected and stop processing packet 223 */ 224 225int 226ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 227 struct ifnet **ifp, struct secpolicy **sp) 228{ 229#ifdef IPSEC 230 struct tdb_ident *tdbi; 231 struct m_tag *mtag; 232 /* XXX int s; */ 233 if (sp == NULL) 234 return 1; 235 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 236 if (mtag != NULL) { 237 tdbi = (struct tdb_ident *)(mtag + 1); 238 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 239 if (*sp == NULL) 240 *error = -EINVAL; /* force silent drop */ 241 m_tag_delete(*m, mtag); 242 } else { 243 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 244 error, inp); 245 } 246 247 /* 248 * There are four return cases: 249 * sp != NULL apply IPsec policy 250 * sp == NULL, error == 0 no IPsec handling needed 251 * sp == NULL, error == -EINVAL discard packet w/o error 252 * sp == NULL, error != 0 discard packet, report error 253 */ 254 if (*sp != NULL) { 255 /* Loop detection, check if ipsec processing already done */ 256 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 257 for (mtag = m_tag_first(*m); mtag != NULL; 258 mtag = m_tag_next(*m, mtag)) { 259 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 260 continue; 261 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 262 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 263 continue; 264 /* 265 * Check if policy has an SA associated with it. 266 * This can happen when an SP has yet to acquire 267 * an SA; e.g. on first reference. If it occurs, 268 * then we let ipsec4_process_packet do its thing. 269 */ 270 if ((*sp)->req->sav == NULL) 271 break; 272 tdbi = (struct tdb_ident *)(mtag + 1); 273 if (tdbi->spi == (*sp)->req->sav->spi && 274 tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 275 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 276 sizeof (union sockaddr_union)) == 0) { 277 /* 278 * No IPsec processing is needed, free 279 * reference to SP. 280 * 281 * NB: null pointer to avoid free at 282 * done: below. 283 */ 284 KEY_FREESP(sp), *sp = NULL; 285 /* XXX splx(s); */ 286 goto done; 287 } 288 } 289 290 /* 291 * Do delayed checksums now because we send before 292 * this is done in the normal processing path. 293 */ 294 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 295 in_delayed_cksum(*m); 296 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 297 } 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->sa_route; 371 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 372 mtu = 373 ro->ro_rt->rt_rmx.rmx_mtu ? 374 ro->ro_rt->rt_rmx.rmx_mtu : 375 ro->ro_rt->rt_ifp->if_mtu; 376 mtu -= ipsechdr; 377 } 378 } 379 KEY_FREESP(&sp); 380 } 381#endif /* IPSEC */ 382 /* XXX else case missing. */ 383 return mtu; 384} 385#endif 386