ip6_ipsec.c revision 171133
1171133Sgnn/*- 2171133Sgnn * Copyright (c) 1982, 1986, 1988, 1993 3171133Sgnn * The Regents of the University of California. All rights reserved. 4171133Sgnn * 5171133Sgnn * Redistribution and use in source and binary forms, with or without 6171133Sgnn * modification, are permitted provided that the following conditions 7171133Sgnn * are met: 8171133Sgnn * 1. Redistributions of source code must retain the above copyright 9171133Sgnn * notice, this list of conditions and the following disclaimer. 10171133Sgnn * 2. Redistributions in binary form must reproduce the above copyright 11171133Sgnn * notice, this list of conditions and the following disclaimer in the 12171133Sgnn * documentation and/or other materials provided with the distribution. 13171133Sgnn * 4. Neither the name of the University nor the names of its contributors 14171133Sgnn * may be used to endorse or promote products derived from this software 15171133Sgnn * without specific prior written permission. 16171133Sgnn * 17171133Sgnn * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18171133Sgnn * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19171133Sgnn * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20171133Sgnn * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21171133Sgnn * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22171133Sgnn * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23171133Sgnn * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24171133Sgnn * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25171133Sgnn * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26171133Sgnn * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27171133Sgnn * SUCH DAMAGE. 28171133Sgnn * 29171133Sgnn * $FreeBSD: head/sys/netinet6/ip6_ipsec.c 171133 2007-07-01 11:41:27Z gnn $ 30171133Sgnn */ 31171133Sgnn 32171133Sgnn#include "opt_ipsec.h" 33171133Sgnn 34171133Sgnn#include <sys/param.h> 35171133Sgnn#include <sys/systm.h> 36171133Sgnn#include <sys/kernel.h> 37171133Sgnn#include <sys/mac.h> 38171133Sgnn#include <sys/malloc.h> 39171133Sgnn#include <sys/mbuf.h> 40171133Sgnn#include <sys/protosw.h> 41171133Sgnn#include <sys/socket.h> 42171133Sgnn#include <sys/socketvar.h> 43171133Sgnn#include <sys/sysctl.h> 44171133Sgnn 45171133Sgnn#include <net/if.h> 46171133Sgnn#include <net/route.h> 47171133Sgnn 48171133Sgnn#include <netinet/in.h> 49171133Sgnn#include <netinet/in_systm.h> 50171133Sgnn#include <netinet/in_var.h> 51171133Sgnn#include <netinet/ip.h> 52171133Sgnn#include <netinet/in_pcb.h> 53171133Sgnn#include <netinet/ip_var.h> 54171133Sgnn#include <netinet/ip_options.h> 55171133Sgnn 56171133Sgnn#include <machine/in_cksum.h> 57171133Sgnn 58171133Sgnn#ifdef FAST_IPSEC 59171133Sgnn#include <netipsec/ipsec.h> 60171133Sgnn#include <netipsec/ipsec6.h> 61171133Sgnn#include <netipsec/xform.h> 62171133Sgnn#include <netipsec/key.h> 63171133Sgnn#ifdef IPSEC_DEBUG 64171133Sgnn#include <netipsec/key_debug.h> 65171133Sgnn#else 66171133Sgnn#define KEYDEBUG(lev,arg) 67171133Sgnn#endif 68171133Sgnn#endif /*FAST_IPSEC*/ 69171133Sgnn 70171133Sgnn#include <netinet6/ip6_ipsec.h> 71171133Sgnn 72171133Sgnnextern struct protosw inet6sw[]; 73171133Sgnn 74171133Sgnn/* 75171133Sgnn * Check if we have to jump over firewall processing for this packet. 76171133Sgnn * Called from ip_input(). 77171133Sgnn * 1 = jump over firewall, 0 = packet goes through firewall. 78171133Sgnn */ 79171133Sgnnint 80171133Sgnnip6_ipsec_filtergif(struct mbuf *m) 81171133Sgnn{ 82171133Sgnn#if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 83171133Sgnn /* 84171133Sgnn * Bypass packet filtering for packets from a tunnel (gif). 85171133Sgnn */ 86171133Sgnn if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 87171133Sgnn return 1; 88171133Sgnn#endif 89171133Sgnn return 0; 90171133Sgnn} 91171133Sgnn 92171133Sgnn/* 93171133Sgnn * Check if this packet has an active SA and needs to be dropped instead 94171133Sgnn * of forwarded. 95171133Sgnn * Called from ip_input(). 96171133Sgnn * 1 = drop packet, 0 = forward packet. 97171133Sgnn */ 98171133Sgnnint 99171133Sgnnip6_ipsec_fwd(struct mbuf *m) 100171133Sgnn{ 101171133Sgnn#ifdef FAST_IPSEC 102171133Sgnn struct m_tag *mtag; 103171133Sgnn struct tdb_ident *tdbi; 104171133Sgnn struct secpolicy *sp; 105171133Sgnn int s, error; 106171133Sgnn mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 107171133Sgnn s = splnet(); 108171133Sgnn if (mtag != NULL) { 109171133Sgnn tdbi = (struct tdb_ident *)(mtag + 1); 110171133Sgnn sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 111171133Sgnn } else { 112171133Sgnn sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 113171133Sgnn IP_FORWARDING, &error); 114171133Sgnn } 115171133Sgnn if (sp == NULL) { /* NB: can happen if error */ 116171133Sgnn splx(s); 117171133Sgnn /*XXX error stat???*/ 118171133Sgnn DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 119171133Sgnn return 1; 120171133Sgnn } 121171133Sgnn 122171133Sgnn /* 123171133Sgnn * Check security policy against packet attributes. 124171133Sgnn */ 125171133Sgnn error = ipsec_in_reject(sp, m); 126171133Sgnn KEY_FREESP(&sp); 127171133Sgnn splx(s); 128171133Sgnn if (error) { 129171133Sgnn ipstat.ips_cantforward++; 130171133Sgnn return 1; 131171133Sgnn } 132171133Sgnn#endif /* FAST_IPSEC */ 133171133Sgnn return 0; 134171133Sgnn} 135171133Sgnn 136171133Sgnn/* 137171133Sgnn * Check if protocol type doesn't have a further header and do IPSEC 138171133Sgnn * decryption or reject right now. Protocols with further headers get 139171133Sgnn * their IPSEC treatment within the protocol specific processing. 140171133Sgnn * Called from ip_input(). 141171133Sgnn * 1 = drop packet, 0 = continue processing packet. 142171133Sgnn */ 143171133Sgnnint 144171133Sgnnip6_ipsec_input(struct mbuf *m, int nxt) 145171133Sgnn 146171133Sgnn{ 147171133Sgnn#ifdef FAST_IPSEC 148171133Sgnn struct m_tag *mtag; 149171133Sgnn struct tdb_ident *tdbi; 150171133Sgnn struct secpolicy *sp; 151171133Sgnn int s, error; 152171133Sgnn /* 153171133Sgnn * enforce IPsec policy checking if we are seeing last header. 154171133Sgnn * note that we do not visit this with protocols with pcb layer 155171133Sgnn * code - like udp/tcp/raw ip. 156171133Sgnn */ 157171133Sgnn if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 && 158171133Sgnn ipsec6_in_reject(m, NULL)) { 159171133Sgnn 160171133Sgnn /* 161171133Sgnn * Check if the packet has already had IPsec processing 162171133Sgnn * done. If so, then just pass it along. This tag gets 163171133Sgnn * set during AH, ESP, etc. input handling, before the 164171133Sgnn * packet is returned to the ip input queue for delivery. 165171133Sgnn */ 166171133Sgnn mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 167171133Sgnn s = splnet(); 168171133Sgnn if (mtag != NULL) { 169171133Sgnn tdbi = (struct tdb_ident *)(mtag + 1); 170171133Sgnn sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 171171133Sgnn } else { 172171133Sgnn sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 173171133Sgnn IP_FORWARDING, &error); 174171133Sgnn } 175171133Sgnn if (sp != NULL) { 176171133Sgnn /* 177171133Sgnn * Check security policy against packet attributes. 178171133Sgnn */ 179171133Sgnn error = ipsec_in_reject(sp, m); 180171133Sgnn KEY_FREESP(&sp); 181171133Sgnn } else { 182171133Sgnn /* XXX error stat??? */ 183171133Sgnn error = EINVAL; 184171133Sgnn DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 185171133Sgnn return 1; 186171133Sgnn } 187171133Sgnn splx(s); 188171133Sgnn if (error) 189171133Sgnn return 1; 190171133Sgnn } 191171133Sgnn#endif /* FAST_IPSEC */ 192171133Sgnn return 0; 193171133Sgnn} 194171133Sgnn 195171133Sgnn/* 196171133Sgnn * Called from ip6_output(). 197171133Sgnn * 1 = drop packet, 0 = continue processing packet, 198171133Sgnn * -1 = packet was reinjected and stop processing packet (FAST_IPSEC only) 199171133Sgnn */ 200171133Sgnn 201171133Sgnnint 202171133Sgnnip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error, 203171133Sgnn struct ifnet **ifp, struct secpolicy **sp) 204171133Sgnn{ 205171133Sgnn#ifdef FAST_IPSEC 206171133Sgnn struct tdb_ident *tdbi; 207171133Sgnn struct m_tag *mtag; 208171133Sgnn int s; 209171133Sgnn if (sp == NULL) 210171133Sgnn return 1; 211171133Sgnn mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 212171133Sgnn if (mtag != NULL) { 213171133Sgnn tdbi = (struct tdb_ident *)(mtag + 1); 214171133Sgnn *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 215171133Sgnn if (*sp == NULL) 216171133Sgnn *error = -EINVAL; /* force silent drop */ 217171133Sgnn m_tag_delete(*m, mtag); 218171133Sgnn } else { 219171133Sgnn *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 220171133Sgnn error, inp); 221171133Sgnn } 222171133Sgnn 223171133Sgnn /* 224171133Sgnn * There are four return cases: 225171133Sgnn * sp != NULL apply IPsec policy 226171133Sgnn * sp == NULL, error == 0 no IPsec handling needed 227171133Sgnn * sp == NULL, error == -EINVAL discard packet w/o error 228171133Sgnn * sp == NULL, error != 0 discard packet, report error 229171133Sgnn */ 230171133Sgnn if (*sp != NULL) { 231171133Sgnn /* Loop detection, check if ipsec processing already done */ 232171133Sgnn KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request")); 233171133Sgnn for (mtag = m_tag_first(*m); mtag != NULL; 234171133Sgnn mtag = m_tag_next(*m, mtag)) { 235171133Sgnn if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 236171133Sgnn continue; 237171133Sgnn if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 238171133Sgnn mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 239171133Sgnn continue; 240171133Sgnn /* 241171133Sgnn * Check if policy has an SA associated with it. 242171133Sgnn * This can happen when an SP has yet to acquire 243171133Sgnn * an SA; e.g. on first reference. If it occurs, 244171133Sgnn * then we let ipsec4_process_packet do its thing. 245171133Sgnn */ 246171133Sgnn if ((*sp)->req->sav == NULL) 247171133Sgnn break; 248171133Sgnn tdbi = (struct tdb_ident *)(mtag + 1); 249171133Sgnn if (tdbi->spi == (*sp)->req->sav->spi && 250171133Sgnn tdbi->proto == (*sp)->req->sav->sah->saidx.proto && 251171133Sgnn bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst, 252171133Sgnn sizeof (union sockaddr_union)) == 0) { 253171133Sgnn /* 254171133Sgnn * No IPsec processing is needed, free 255171133Sgnn * reference to SP. 256171133Sgnn * 257171133Sgnn * NB: null pointer to avoid free at 258171133Sgnn * done: below. 259171133Sgnn */ 260171133Sgnn KEY_FREESP(sp), sp = NULL; 261171133Sgnn splx(s); 262171133Sgnn goto done; 263171133Sgnn } 264171133Sgnn } 265171133Sgnn 266171133Sgnn /* 267171133Sgnn * Do delayed checksums now because we send before 268171133Sgnn * this is done in the normal processing path. 269171133Sgnn */ 270171133Sgnn if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 271171133Sgnn in_delayed_cksum(*m); 272171133Sgnn (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 273171133Sgnn } 274171133Sgnn 275171133Sgnn /* 276171133Sgnn * Preserve KAME behaviour: ENOENT can be returned 277171133Sgnn * when an SA acquire is in progress. Don't propagate 278171133Sgnn * this to user-level; it confuses applications. 279171133Sgnn * 280171133Sgnn * XXX this will go away when the SADB is redone. 281171133Sgnn */ 282171133Sgnn if (*error == ENOENT) 283171133Sgnn *error = 0; 284171133Sgnn goto do_ipsec; 285171133Sgnn } else { /* sp == NULL */ 286171133Sgnn if (*error != 0) { 287171133Sgnn /* 288171133Sgnn * Hack: -EINVAL is used to signal that a packet 289171133Sgnn * should be silently discarded. This is typically 290171133Sgnn * because we asked key management for an SA and 291171133Sgnn * it was delayed (e.g. kicked up to IKE). 292171133Sgnn */ 293171133Sgnn if (*error == -EINVAL) 294171133Sgnn *error = 0; 295171133Sgnn goto bad; 296171133Sgnn } else { 297171133Sgnn /* No IPsec processing for this packet. */ 298171133Sgnn } 299171133Sgnn } 300171133Sgnndone: 301171133Sgnn if (sp != NULL) 302171133Sgnn if (*sp != NULL) 303171133Sgnn KEY_FREESP(sp); 304171133Sgnn return 0; 305171133Sgnndo_ipsec: 306171133Sgnn return -1; 307171133Sgnnbad: 308171133Sgnn if (sp != NULL) 309171133Sgnn if (*sp != NULL) 310171133Sgnn KEY_FREESP(sp); 311171133Sgnn return 1; 312171133Sgnn#endif /* FAST_IPSEC */ 313171133Sgnn return 0; 314171133Sgnn} 315171133Sgnn 316171133Sgnn/* 317171133Sgnn * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 318171133Sgnn * Called from ip_forward(). 319171133Sgnn * Returns MTU suggestion for ICMP needfrag reply. 320171133Sgnn */ 321171133Sgnnint 322171133Sgnnip6_ipsec_mtu(struct mbuf *m) 323171133Sgnn{ 324171133Sgnn int mtu = 0; 325171133Sgnn /* 326171133Sgnn * If the packet is routed over IPsec tunnel, tell the 327171133Sgnn * originator the tunnel MTU. 328171133Sgnn * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 329171133Sgnn * XXX quickhack!!! 330171133Sgnn */ 331171133Sgnn struct secpolicy *sp = NULL; 332171133Sgnn int ipsecerror; 333171133Sgnn int ipsechdr; 334171133Sgnn struct route *ro; 335171133Sgnn#ifdef FAST_IPSEC 336171133Sgnn sp = ipsec_getpolicybyaddr(m, 337171133Sgnn IPSEC_DIR_OUTBOUND, 338171133Sgnn IP_FORWARDING, 339171133Sgnn &ipsecerror); 340171133Sgnn#endif /* FAST_IPSEC */ 341171133Sgnn if (sp != NULL) { 342171133Sgnn /* count IPsec header size */ 343171133Sgnn ipsechdr = ipsec4_hdrsiz(m, 344171133Sgnn IPSEC_DIR_OUTBOUND, 345171133Sgnn NULL); 346171133Sgnn 347171133Sgnn /* 348171133Sgnn * find the correct route for outer IPv4 349171133Sgnn * header, compute tunnel MTU. 350171133Sgnn */ 351171133Sgnn if (sp->req != NULL && 352171133Sgnn sp->req->sav != NULL && 353171133Sgnn sp->req->sav->sah != NULL) { 354171133Sgnn ro = &sp->req->sav->sah->sa_route; 355171133Sgnn if (ro->ro_rt && ro->ro_rt->rt_ifp) { 356171133Sgnn mtu = 357171133Sgnn ro->ro_rt->rt_rmx.rmx_mtu ? 358171133Sgnn ro->ro_rt->rt_rmx.rmx_mtu : 359171133Sgnn ro->ro_rt->rt_ifp->if_mtu; 360171133Sgnn mtu -= ipsechdr; 361171133Sgnn } 362171133Sgnn } 363171133Sgnn#ifdef FAST_IPSEC 364171133Sgnn KEY_FREESP(&sp); 365171133Sgnn#endif /* FAST_IPSEC */ 366171133Sgnn } 367171133Sgnn return mtu; 368171133Sgnn} 369171133Sgnn 370