ip6_ipsec.c revision 180090
121308Sache/*- 221308Sache * Copyright (c) 1982, 1986, 1988, 1993 321308Sache * The Regents of the University of California. All rights reserved. 421308Sache * 521308Sache * Redistribution and use in source and binary forms, with or without 621308Sache * modification, are permitted provided that the following conditions 721308Sache * are met: 821308Sache * 1. Redistributions of source code must retain the above copyright 921308Sache * notice, this list of conditions and the following disclaimer. 1021308Sache * 2. Redistributions in binary form must reproduce the above copyright 1121308Sache * notice, this list of conditions and the following disclaimer in the 1221308Sache * documentation and/or other materials provided with the distribution. 1321308Sache * 4. Neither the name of the University nor the names of its contributors 1421308Sache * may be used to endorse or promote products derived from this software 1521308Sache * without specific prior written permission. 1621308Sache * 1721308Sache * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 1821308Sache * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1921308Sache * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2021308Sache * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2121308Sache * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2221308Sache * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2321308Sache * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2421308Sache * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2521308Sache * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2621308Sache * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2721308Sache * SUCH DAMAGE. 2821308Sache */ 2921308Sache 3021308Sache#include <sys/cdefs.h> 3121308Sache__FBSDID("$FreeBSD: head/sys/netinet6/ip6_ipsec.c 180090 2008-06-29 07:34:21Z bz $"); 3221308Sache 3321308Sache#include "opt_ipsec.h" 3421308Sache 3521308Sache#include <sys/param.h> 3621308Sache#include <sys/systm.h> 3721308Sache#include <sys/kernel.h> 3821308Sache#include <sys/mac.h> 3921308Sache#include <sys/malloc.h> 4021308Sache#include <sys/mbuf.h> 4121308Sache#include <sys/protosw.h> 4221308Sache#include <sys/socket.h> 4321308Sache#include <sys/socketvar.h> 4421308Sache#include <sys/sysctl.h> 4521308Sache 4621308Sache#include <net/if.h> 4721308Sache#include <net/route.h> 4821308Sache 4921308Sache#include <netinet/in.h> 50#include <netinet/in_systm.h> 51#include <netinet/in_var.h> 52#include <netinet/ip.h> 53#include <netinet/ip6.h> 54#include <netinet/in_pcb.h> 55#include <netinet/ip_var.h> 56#include <netinet/ip_options.h> 57 58#include <machine/in_cksum.h> 59 60#ifdef IPSEC 61#include <netipsec/ipsec.h> 62#include <netipsec/ipsec6.h> 63#include <netipsec/xform.h> 64#include <netipsec/key.h> 65#ifdef IPSEC_DEBUG 66#include <netipsec/key_debug.h> 67#else 68#define KEYDEBUG(lev,arg) 69#endif 70#endif /*IPSEC*/ 71 72#include <netinet6/ip6_ipsec.h> 73#include <netinet6/ip6_var.h> 74 75extern struct protosw inet6sw[]; 76 77/* 78 * Check if we have to jump over firewall processing for this packet. 79 * Called from ip_input(). 80 * 1 = jump over firewall, 0 = packet goes through firewall. 81 */ 82int 83ip6_ipsec_filtertunnel(struct mbuf *m) 84{ 85#if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL) 86 /* 87 * Bypass packet filtering for packets from a tunnel. 88 */ 89 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 90 return 1; 91#endif 92 return 0; 93} 94 95/* 96 * Check if this packet has an active SA and needs to be dropped instead 97 * of forwarded. 98 * Called from ip_input(). 99 * 1 = drop packet, 0 = forward packet. 100 */ 101int 102ip6_ipsec_fwd(struct mbuf *m) 103{ 104#ifdef IPSEC 105 struct m_tag *mtag; 106 struct tdb_ident *tdbi; 107 struct secpolicy *sp; 108 int s, error; 109 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 110 s = splnet(); 111 if (mtag != NULL) { 112 tdbi = (struct tdb_ident *)(mtag + 1); 113 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 114 } else { 115 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 116 IP_FORWARDING, &error); 117 } 118 if (sp == NULL) { /* NB: can happen if error */ 119 splx(s); 120 /*XXX error stat???*/ 121 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 122 return 1; 123 } 124 125 /* 126 * Check security policy against packet attributes. 127 */ 128 error = ipsec_in_reject(sp, m); 129 KEY_FREESP(&sp); 130 splx(s); 131 if (error) { 132 ip6stat.ip6s_cantforward++; 133 return 1; 134 } 135#endif /* IPSEC */ 136 return 0; 137} 138 139/* 140 * Check if protocol type doesn't have a further header and do IPSEC 141 * decryption or reject right now. Protocols with further headers get 142 * their IPSEC treatment within the protocol specific processing. 143 * Called from ip_input(). 144 * 1 = drop packet, 0 = continue processing packet. 145 */ 146int 147ip6_ipsec_input(struct mbuf *m, int nxt) 148{ 149#ifdef IPSEC 150 struct m_tag *mtag; 151 struct tdb_ident *tdbi; 152 struct secpolicy *sp; 153 int s, error; 154 /* 155 * enforce IPsec policy checking if we are seeing last header. 156 * note that we do not visit this with protocols with pcb layer 157 * code - like udp/tcp/raw ip. 158 */ 159 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 160 ipsec6_in_reject(m, NULL)) { 161 162 /* 163 * Check if the packet has already had IPsec processing 164 * done. If so, then just pass it along. This tag gets 165 * set during AH, ESP, etc. input handling, before the 166 * packet is returned to the ip input queue for delivery. 167 */ 168 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 169 s = splnet(); 170 if (mtag != NULL) { 171 tdbi = (struct tdb_ident *)(mtag + 1); 172 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 173 } else { 174 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 175 IP_FORWARDING, &error); 176 } 177 if (sp != NULL) { 178 /* 179 * Check security policy against packet attributes. 180 */ 181 error = ipsec_in_reject(sp, m); 182 KEY_FREESP(&sp); 183 } else { 184 /* XXX error stat??? */ 185 error = EINVAL; 186 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 187 return 1; 188 } 189 splx(s); 190 if (error) 191 return 1; 192 } 193#endif /* IPSEC */ 194 return 0; 195} 196 197/* 198 * Called from ip6_output(). 199 * 1 = drop packet, 0 = continue processing packet, 200 * -1 = packet was reinjected and stop processing packet 201 */ 202 203int 204ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 205 struct ifnet **ifp, struct secpolicy **sp) 206{ 207#ifdef IPSEC 208 struct tdb_ident *tdbi; 209 struct m_tag *mtag; 210 /* XXX int s; */ 211 if (sp == NULL) 212 return 1; 213 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 214 if (mtag != NULL) { 215 tdbi = (struct tdb_ident *)(mtag + 1); 216 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 217 if (*sp == NULL) 218 *error = -EINVAL; /* force silent drop */ 219 m_tag_delete(*m, mtag); 220 } else { 221 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 222 error, inp); 223 } 224 225 /* 226 * There are four return cases: 227 * sp != NULL apply IPsec policy 228 * sp == NULL, error == 0 no IPsec handling needed 229 * sp == NULL, error == -EINVAL discard packet w/o error 230 * sp == NULL, error != 0 discard packet, report error 231 */ 232 if (*sp != NULL) { 233 /* Loop detection, check if ipsec processing already done */ 234 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 235 for (mtag = m_tag_first(*m); mtag != NULL; 236 mtag = m_tag_next(*m, mtag)) { 237 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 238 continue; 239 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 240 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 241 continue; 242 /* 243 * Check if policy has an SA associated with it. 244 * This can happen when an SP has yet to acquire 245 * an SA; e.g. on first reference. If it occurs, 246 * then we let ipsec4_process_packet do its thing. 247 */ 248 if ((*sp)->req->sav == NULL) 249 break; 250 tdbi = (struct tdb_ident *)(mtag + 1); 251 if (tdbi->spi == (*sp)->req->sav->spi && 252 tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 253 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 254 sizeof (union sockaddr_union)) == 0) { 255 /* 256 * No IPsec processing is needed, free 257 * reference to SP. 258 * 259 * NB: null pointer to avoid free at 260 * done: below. 261 */ 262 KEY_FREESP(sp), *sp = NULL; 263 /* XXX splx(s); */ 264 goto done; 265 } 266 } 267 268 /* 269 * Do delayed checksums now because we send before 270 * this is done in the normal processing path. 271 */ 272 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 273 in_delayed_cksum(*m); 274 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 275 } 276 277 /* 278 * Preserve KAME behaviour: ENOENT can be returned 279 * when an SA acquire is in progress. Don't propagate 280 * this to user-level; it confuses applications. 281 * 282 * XXX this will go away when the SADB is redone. 283 */ 284 if (*error == ENOENT) 285 *error = 0; 286 goto do_ipsec; 287 } else { /* sp == NULL */ 288 if (*error != 0) { 289 /* 290 * Hack: -EINVAL is used to signal that a packet 291 * should be silently discarded. This is typically 292 * because we asked key management for an SA and 293 * it was delayed (e.g. kicked up to IKE). 294 */ 295 if (*error == -EINVAL) 296 *error = 0; 297 goto bad; 298 } else { 299 /* No IPsec processing for this packet. */ 300 } 301 } 302done: 303 return 0; 304do_ipsec: 305 return -1; 306bad: 307 return 1; 308#endif /* IPSEC */ 309 return 0; 310} 311 312#if 0 313/* 314 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 315 * Called from ip_forward(). 316 * Returns MTU suggestion for ICMP needfrag reply. 317 */ 318int 319ip6_ipsec_mtu(struct mbuf *m) 320{ 321 int mtu = 0; 322 /* 323 * If the packet is routed over IPsec tunnel, tell the 324 * originator the tunnel MTU. 325 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 326 * XXX quickhack!!! 327 */ 328#ifdef IPSEC 329 struct secpolicy *sp = NULL; 330 int ipsecerror; 331 int ipsechdr; 332 struct route *ro; 333 sp = ipsec_getpolicybyaddr(m, 334 IPSEC_DIR_OUTBOUND, 335 IP_FORWARDING, 336 &ipsecerror); 337 if (sp != NULL) { 338 /* count IPsec header size */ 339 ipsechdr = ipsec4_hdrsiz(m, 340 IPSEC_DIR_OUTBOUND, 341 NULL); 342 343 /* 344 * find the correct route for outer IPv4 345 * header, compute tunnel MTU. 346 */ 347 if (sp->req != NULL && 348 sp->req->sav != NULL && 349 sp->req->sav->sah != NULL) { 350 ro = &sp->req->sav->sah->sa_route; 351 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 352 mtu = 353 ro->ro_rt->rt_rmx.rmx_mtu ? 354 ro->ro_rt->rt_rmx.rmx_mtu : 355 ro->ro_rt->rt_ifp->if_mtu; 356 mtu -= ipsechdr; 357 } 358 } 359 KEY_FREESP(&sp); 360 } 361#endif /* IPSEC */ 362 /* XXX else case missing. */ 363 return mtu; 364} 365#endif 366