ip6_ipsec.c revision 188306
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 188306 2009-02-08 09:27:07Z bz $"); 32 33#include "opt_ipsec.h" 34 35#include <sys/param.h> 36#include <sys/systm.h> 37#include <sys/kernel.h> 38#include <sys/mac.h> 39#include <sys/malloc.h> 40#include <sys/mbuf.h> 41#include <sys/protosw.h> 42#include <sys/socket.h> 43#include <sys/socketvar.h> 44#include <sys/sysctl.h> 45#include <sys/vimage.h> 46 47#include <net/if.h> 48#include <net/route.h> 49 50#include <netinet/in.h> 51#include <netinet/in_systm.h> 52#include <netinet/in_var.h> 53#include <netinet/ip.h> 54#include <netinet/ip6.h> 55#include <netinet/in_pcb.h> 56#include <netinet/ip_var.h> 57#include <netinet/ip_options.h> 58 59#include <machine/in_cksum.h> 60 61#ifdef IPSEC 62#include <netipsec/ipsec.h> 63#include <netipsec/ipsec6.h> 64#include <netipsec/xform.h> 65#include <netipsec/key.h> 66#ifdef IPSEC_DEBUG 67#include <netipsec/key_debug.h> 68#else 69#define KEYDEBUG(lev,arg) 70#endif 71#endif /*IPSEC*/ 72 73#include <netinet6/ip6_ipsec.h> 74#include <netinet6/ip6_var.h> 75#include <netinet6/vinet6.h> 76 77extern struct protosw inet6sw[]; 78 79/* 80 * Check if we have to jump over firewall processing for this packet. 81 * Called from ip_input(). 82 * 1 = jump over firewall, 0 = packet goes through firewall. 83 */ 84int 85ip6_ipsec_filtertunnel(struct mbuf *m) 86{ 87#if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL) 88 /* 89 * Bypass packet filtering for packets from a tunnel. 90 */ 91 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 92 return 1; 93#endif 94 return 0; 95} 96 97/* 98 * Check if this packet has an active SA and needs to be dropped instead 99 * of forwarded. 100 * Called from ip_input(). 101 * 1 = drop packet, 0 = forward packet. 102 */ 103int 104ip6_ipsec_fwd(struct mbuf *m) 105{ 106#ifdef IPSEC 107 INIT_VNET_INET6(curvnet); 108 INIT_VNET_IPSEC(curvnet); 109 struct m_tag *mtag; 110 struct tdb_ident *tdbi; 111 struct secpolicy *sp; 112 int s, error; 113 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 114 s = splnet(); 115 if (mtag != NULL) { 116 tdbi = (struct tdb_ident *)(mtag + 1); 117 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 118 } else { 119 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 120 IP_FORWARDING, &error); 121 } 122 if (sp == NULL) { /* NB: can happen if error */ 123 splx(s); 124 /*XXX error stat???*/ 125 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 126 return 1; 127 } 128 129 /* 130 * Check security policy against packet attributes. 131 */ 132 error = ipsec_in_reject(sp, m); 133 KEY_FREESP(&sp); 134 splx(s); 135 if (error) { 136 V_ip6stat.ip6s_cantforward++; 137 return 1; 138 } 139#endif /* IPSEC */ 140 return 0; 141} 142 143/* 144 * Check if protocol type doesn't have a further header and do IPSEC 145 * decryption or reject right now. Protocols with further headers get 146 * their IPSEC treatment within the protocol specific processing. 147 * Called from ip_input(). 148 * 1 = drop packet, 0 = continue processing packet. 149 */ 150int 151ip6_ipsec_input(struct mbuf *m, int nxt) 152{ 153#ifdef IPSEC 154 INIT_VNET_IPSEC(curvnet); 155 struct m_tag *mtag; 156 struct tdb_ident *tdbi; 157 struct secpolicy *sp; 158 int s, error; 159 /* 160 * enforce IPsec policy checking if we are seeing last header. 161 * note that we do not visit this with protocols with pcb layer 162 * code - like udp/tcp/raw ip. 163 */ 164 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 165 ipsec6_in_reject(m, NULL)) { 166 167 /* 168 * Check if the packet has already had IPsec processing 169 * done. If so, then just pass it along. This tag gets 170 * set during AH, ESP, etc. input handling, before the 171 * packet is returned to the ip input queue for delivery. 172 */ 173 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 174 s = splnet(); 175 if (mtag != NULL) { 176 tdbi = (struct tdb_ident *)(mtag + 1); 177 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 178 } else { 179 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 180 IP_FORWARDING, &error); 181 } 182 if (sp != NULL) { 183 /* 184 * Check security policy against packet attributes. 185 */ 186 error = ipsec_in_reject(sp, m); 187 KEY_FREESP(&sp); 188 } else { 189 /* XXX error stat??? */ 190 error = EINVAL; 191 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 192 return 1; 193 } 194 splx(s); 195 if (error) 196 return 1; 197 } 198#endif /* IPSEC */ 199 return 0; 200} 201 202/* 203 * Called from ip6_output(). 204 * 1 = drop packet, 0 = continue processing packet, 205 * -1 = packet was reinjected and stop processing packet 206 */ 207 208int 209ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 210 struct ifnet **ifp, struct secpolicy **sp) 211{ 212#ifdef IPSEC 213 struct tdb_ident *tdbi; 214 struct m_tag *mtag; 215 /* XXX int s; */ 216 if (sp == NULL) 217 return 1; 218 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 219 if (mtag != NULL) { 220 tdbi = (struct tdb_ident *)(mtag + 1); 221 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 222 if (*sp == NULL) 223 *error = -EINVAL; /* force silent drop */ 224 m_tag_delete(*m, mtag); 225 } else { 226 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 227 error, inp); 228 } 229 230 /* 231 * There are four return cases: 232 * sp != NULL apply IPsec policy 233 * sp == NULL, error == 0 no IPsec handling needed 234 * sp == NULL, error == -EINVAL discard packet w/o error 235 * sp == NULL, error != 0 discard packet, report error 236 */ 237 if (*sp != NULL) { 238 /* Loop detection, check if ipsec processing already done */ 239 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 240 for (mtag = m_tag_first(*m); mtag != NULL; 241 mtag = m_tag_next(*m, mtag)) { 242 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 243 continue; 244 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 245 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 246 continue; 247 /* 248 * Check if policy has an SA associated with it. 249 * This can happen when an SP has yet to acquire 250 * an SA; e.g. on first reference. If it occurs, 251 * then we let ipsec4_process_packet do its thing. 252 */ 253 if ((*sp)->req->sav == NULL) 254 break; 255 tdbi = (struct tdb_ident *)(mtag + 1); 256 if (tdbi->spi == (*sp)->req->sav->spi && 257 tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 258 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 259 sizeof (union sockaddr_union)) == 0) { 260 /* 261 * No IPsec processing is needed, free 262 * reference to SP. 263 * 264 * NB: null pointer to avoid free at 265 * done: below. 266 */ 267 KEY_FREESP(sp), *sp = NULL; 268 /* XXX splx(s); */ 269 goto done; 270 } 271 } 272 273 /* 274 * Do delayed checksums now because we send before 275 * this is done in the normal processing path. 276 */ 277 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 278 in_delayed_cksum(*m); 279 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 280 } 281 282 /* 283 * Preserve KAME behaviour: ENOENT can be returned 284 * when an SA acquire is in progress. Don't propagate 285 * this to user-level; it confuses applications. 286 * 287 * XXX this will go away when the SADB is redone. 288 */ 289 if (*error == ENOENT) 290 *error = 0; 291 goto do_ipsec; 292 } else { /* sp == NULL */ 293 if (*error != 0) { 294 /* 295 * Hack: -EINVAL is used to signal that a packet 296 * should be silently discarded. This is typically 297 * because we asked key management for an SA and 298 * it was delayed (e.g. kicked up to IKE). 299 */ 300 if (*error == -EINVAL) 301 *error = 0; 302 goto bad; 303 } else { 304 /* No IPsec processing for this packet. */ 305 } 306 } 307done: 308 return 0; 309do_ipsec: 310 return -1; 311bad: 312 return 1; 313#endif /* IPSEC */ 314 return 0; 315} 316 317#if 0 318/* 319 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 320 * Called from ip_forward(). 321 * Returns MTU suggestion for ICMP needfrag reply. 322 */ 323int 324ip6_ipsec_mtu(struct mbuf *m) 325{ 326 int mtu = 0; 327 /* 328 * If the packet is routed over IPsec tunnel, tell the 329 * originator the tunnel MTU. 330 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 331 * XXX quickhack!!! 332 */ 333#ifdef IPSEC 334 struct secpolicy *sp = NULL; 335 int ipsecerror; 336 int ipsechdr; 337 struct route *ro; 338 sp = ipsec_getpolicybyaddr(m, 339 IPSEC_DIR_OUTBOUND, 340 IP_FORWARDING, 341 &ipsecerror); 342 if (sp != NULL) { 343 /* count IPsec header size */ 344 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 345 346 /* 347 * find the correct route for outer IPv4 348 * header, compute tunnel MTU. 349 */ 350 if (sp->req != NULL && 351 sp->req->sav != NULL && 352 sp->req->sav->sah != NULL) { 353 ro = &sp->req->sav->sah->sa_route; 354 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 355 mtu = 356 ro->ro_rt->rt_rmx.rmx_mtu ? 357 ro->ro_rt->rt_rmx.rmx_mtu : 358 ro->ro_rt->rt_ifp->if_mtu; 359 mtu -= ipsechdr; 360 } 361 } 362 KEY_FREESP(&sp); 363 } 364#endif /* IPSEC */ 365 /* XXX else case missing. */ 366 return mtu; 367} 368#endif 369