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: releng/10.3/sys/netinet6/ip6_ipsec.c 283901 2015-06-02 03:14:42Z ae $"); 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/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(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 ip6_input(). 100 * 1 = jump over firewall, 0 = packet goes through firewall. 101 */ 102int 103ip6_ipsec_filtertunnel(struct mbuf *m) 104{ 105#ifdef IPSEC 106 107 /* 108 * Bypass packet filtering for packets previously handled by IPsec. 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 ip6_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 error; 131 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 132 if (mtag != NULL) { 133 tdbi = (struct tdb_ident *)(mtag + 1); 134 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 135 } else { 136 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 137 IP_FORWARDING, &error); 138 } 139 if (sp == NULL) { /* NB: can happen if error */ 140 /*XXX error stat???*/ 141 DPRINTF(("%s: no SP for forwarding\n", __func__)); /*XXX*/ 142 return 1; 143 } 144 145 /* 146 * Check security policy against packet attributes. 147 */ 148 error = ipsec_in_reject(sp, m); 149 KEY_FREESP(&sp); 150 if (error) { 151 IP6STAT_INC(ip6s_cantforward); 152 return 1; 153 } 154#endif /* IPSEC */ 155 return 0; 156} 157 158/* 159 * Check if protocol type doesn't have a further header and do IPSEC 160 * decryption or reject right now. Protocols with further headers get 161 * their IPSEC treatment within the protocol specific processing. 162 * Called from ip6_input(). 163 * 1 = drop packet, 0 = continue processing packet. 164 */ 165int 166ip6_ipsec_input(struct mbuf *m, int nxt) 167{ 168#ifdef IPSEC 169 struct m_tag *mtag; 170 struct tdb_ident *tdbi; 171 struct secpolicy *sp; 172 int error; 173 /* 174 * enforce IPsec policy checking if we are seeing last header. 175 * note that we do not visit this with protocols with pcb layer 176 * code - like udp/tcp/raw ip. 177 */ 178 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 179 ipsec6_in_reject(m, NULL)) { 180 181 /* 182 * Check if the packet has already had IPsec processing 183 * done. If so, then just pass it along. This tag gets 184 * set during AH, ESP, etc. input handling, before the 185 * packet is returned to the ip input queue for delivery. 186 */ 187 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 188 if (mtag != NULL) { 189 tdbi = (struct tdb_ident *)(mtag + 1); 190 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 191 } else { 192 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 193 IP_FORWARDING, &error); 194 } 195 if (sp != NULL) { 196 /* 197 * Check security policy against packet attributes. 198 */ 199 error = ipsec_in_reject(sp, m); 200 KEY_FREESP(&sp); 201 } else { 202 /* XXX error stat??? */ 203 error = EINVAL; 204 DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/ 205 return 1; 206 } 207 if (error) 208 return 1; 209 } 210#endif /* IPSEC */ 211 return 0; 212} 213 214/* 215 * Called from ip6_output(). 216 * 1 = drop packet, 0 = continue processing packet, 217 * -1 = packet was reinjected and stop processing packet 218 */ 219 220int 221ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 222 struct ifnet **ifp) 223{ 224#ifdef IPSEC 225 struct secpolicy *sp = NULL; 226 struct tdb_ident *tdbi; 227 struct m_tag *mtag; 228 /* XXX int s; */ 229 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 230 if (mtag != NULL) { 231 tdbi = (struct tdb_ident *)(mtag + 1); 232 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 233 if (sp == NULL) 234 *error = -EINVAL; /* force silent drop */ 235 m_tag_delete(*m, mtag); 236 } else { 237 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 238 error, inp); 239 } 240 241 /* 242 * There are four return cases: 243 * sp != NULL apply IPsec policy 244 * sp == NULL, error == 0 no IPsec handling needed 245 * sp == NULL, error == -EINVAL discard packet w/o error 246 * sp == NULL, error != 0 discard packet, report error 247 */ 248 if (sp != NULL) { 249 /* Loop detection, check if ipsec processing already done */ 250 KASSERT(sp->req != NULL, ("ip_output: no ipsec request")); 251 for (mtag = m_tag_first(*m); mtag != NULL; 252 mtag = m_tag_next(*m, mtag)) { 253 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 254 continue; 255 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 256 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 257 continue; 258 /* 259 * Check if policy has no SA associated with it. 260 * This can happen when an SP has yet to acquire 261 * an SA; e.g. on first reference. If it occurs, 262 * then we let ipsec4_process_packet do its thing. 263 */ 264 if (sp->req->sav == NULL) 265 break; 266 tdbi = (struct tdb_ident *)(mtag + 1); 267 if (tdbi->spi == sp->req->sav->spi && 268 tdbi->proto == sp->req->sav->sah->saidx.proto && 269 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst, 270 sizeof (union sockaddr_union)) == 0) { 271 /* 272 * No IPsec processing is needed, free 273 * reference to SP. 274 */ 275 goto done; 276 } 277 } 278 279 /* 280 * Do delayed checksums now because we send before 281 * this is done in the normal processing path. 282 */ 283#ifdef INET 284 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 285 in_delayed_cksum(*m); 286 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 287 } 288#endif 289 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 290 in6_delayed_cksum(*m, (*m)->m_pkthdr.len - sizeof(struct ip6_hdr), 291 sizeof(struct ip6_hdr)); 292 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; 293 } 294#ifdef SCTP 295 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { 296 sctp_delayed_cksum(*m, sizeof(struct ip6_hdr)); 297 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; 298 } 299#endif 300 301 /* NB: callee frees mbuf */ 302 *error = ipsec6_process_packet(*m, sp->req); 303 304 if (*error == EJUSTRETURN) { 305 /* 306 * We had a SP with a level of 'use' and no SA. We 307 * will just continue to process the packet without 308 * IPsec processing. 309 */ 310 *error = 0; 311 goto done; 312 } 313 314 /* 315 * Preserve KAME behaviour: ENOENT can be returned 316 * when an SA acquire is in progress. Don't propagate 317 * this to user-level; it confuses applications. 318 * 319 * XXX this will go away when the SADB is redone. 320 */ 321 if (*error == ENOENT) 322 *error = 0; 323 goto reinjected; 324 } else { /* sp == NULL */ 325 if (*error != 0) { 326 /* 327 * Hack: -EINVAL is used to signal that a packet 328 * should be silently discarded. This is typically 329 * because we asked key management for an SA and 330 * it was delayed (e.g. kicked up to IKE). 331 */ 332 if (*error == -EINVAL) 333 *error = 0; 334 goto bad; 335 } else { 336 /* No IPsec processing for this packet. */ 337 } 338 } 339done: 340 if (sp != NULL) 341 KEY_FREESP(&sp); 342 return 0; 343reinjected: 344 if (sp != NULL) 345 KEY_FREESP(&sp); 346 return -1; 347bad: 348 if (sp != NULL) 349 KEY_FREESP(&sp); 350 return 1; 351#endif /* IPSEC */ 352 return 0; 353} 354 355#if 0 356/* 357 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 358 * Called from ip_forward(). 359 * Returns MTU suggestion for ICMP needfrag reply. 360 */ 361int 362ip6_ipsec_mtu(struct mbuf *m) 363{ 364 int mtu = 0; 365 /* 366 * If the packet is routed over IPsec tunnel, tell the 367 * originator the tunnel MTU. 368 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 369 * XXX quickhack!!! 370 */ 371#ifdef IPSEC 372 struct secpolicy *sp = NULL; 373 int ipsecerror; 374 int ipsechdr; 375 struct route *ro; 376 sp = ipsec_getpolicybyaddr(m, 377 IPSEC_DIR_OUTBOUND, 378 IP_FORWARDING, 379 &ipsecerror); 380 if (sp != NULL) { 381 /* count IPsec header size */ 382 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 383 384 /* 385 * find the correct route for outer IPv4 386 * header, compute tunnel MTU. 387 */ 388 if (sp->req != NULL && 389 sp->req->sav != NULL && 390 sp->req->sav->sah != NULL) { 391 ro = &sp->req->sav->sah->route_cache.sa_route; 392 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 393 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu : 394 ro->ro_rt->rt_ifp->if_mtu; 395 mtu -= ipsechdr; 396 } 397 } 398 KEY_FREESP(&sp); 399 } 400#endif /* IPSEC */ 401 /* XXX else case missing. */ 402 return mtu; 403} 404#endif 405