1155179Sandre/*- 2155179Sandre * Copyright (c) 1982, 1986, 1988, 1993 3155179Sandre * The Regents of the University of California. All rights reserved. 4155179Sandre * 5155179Sandre * Redistribution and use in source and binary forms, with or without 6155179Sandre * modification, are permitted provided that the following conditions 7155179Sandre * are met: 8155179Sandre * 1. Redistributions of source code must retain the above copyright 9155179Sandre * notice, this list of conditions and the following disclaimer. 10155179Sandre * 2. Redistributions in binary form must reproduce the above copyright 11155179Sandre * notice, this list of conditions and the following disclaimer in the 12155179Sandre * documentation and/or other materials provided with the distribution. 13155179Sandre * 4. Neither the name of the University nor the names of its contributors 14155179Sandre * may be used to endorse or promote products derived from this software 15155179Sandre * without specific prior written permission. 16155179Sandre * 17155179Sandre * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18155179Sandre * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19155179Sandre * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20155179Sandre * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21155179Sandre * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22155179Sandre * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23155179Sandre * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24155179Sandre * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25155179Sandre * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26155179Sandre * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27155179Sandre * SUCH DAMAGE. 28155179Sandre */ 29155179Sandre 30172467Ssilby#include <sys/cdefs.h> 31172467Ssilby__FBSDID("$FreeBSD$"); 32172467Ssilby 33155179Sandre#include "opt_ipsec.h" 34188066Srrs#include "opt_sctp.h" 35155179Sandre 36155179Sandre#include <sys/param.h> 37155179Sandre#include <sys/systm.h> 38177175Sbz#include <sys/errno.h> 39155179Sandre#include <sys/kernel.h> 40155179Sandre#include <sys/malloc.h> 41155179Sandre#include <sys/mbuf.h> 42155179Sandre#include <sys/protosw.h> 43155179Sandre#include <sys/socket.h> 44155179Sandre#include <sys/socketvar.h> 45155179Sandre#include <sys/sysctl.h> 46155179Sandre 47155179Sandre#include <net/if.h> 48155179Sandre#include <net/route.h> 49195699Srwatson#include <net/vnet.h> 50155179Sandre 51155179Sandre#include <netinet/in.h> 52155179Sandre#include <netinet/in_systm.h> 53155179Sandre#include <netinet/in_var.h> 54155179Sandre#include <netinet/ip.h> 55155179Sandre#include <netinet/in_pcb.h> 56155179Sandre#include <netinet/ip_var.h> 57155179Sandre#include <netinet/ip_options.h> 58155179Sandre#include <netinet/ip_ipsec.h> 59188066Srrs#ifdef SCTP 60188066Srrs#include <netinet/sctp_crc32.h> 61188066Srrs#endif 62155179Sandre 63155179Sandre#include <machine/in_cksum.h> 64155179Sandre 65171167Sgnn#ifdef IPSEC 66155179Sandre#include <netipsec/ipsec.h> 67155179Sandre#include <netipsec/xform.h> 68155179Sandre#include <netipsec/key.h> 69171167Sgnn#endif /*IPSEC*/ 70155179Sandre 71155179Sandreextern struct protosw inetsw[]; 72155179Sandre 73195699Srwatson#ifdef IPSEC 74195699Srwatson#ifdef IPSEC_FILTERTUNNEL 75215701Sdimstatic VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 1; 76195699Srwatson#else 77215701Sdimstatic VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 0; 78192648Sbz#endif 79195727Srwatson#define V_ip4_ipsec_filtertunnel VNET(ip4_ipsec_filtertunnel) 80192648Sbz 81195699SrwatsonSYSCTL_DECL(_net_inet_ipsec); 82195699SrwatsonSYSCTL_VNET_INT(_net_inet_ipsec, OID_AUTO, filtertunnel, 83195699Srwatson CTLFLAG_RW, &VNET_NAME(ip4_ipsec_filtertunnel), 0, 84195699Srwatson "If set filter packets from an IPsec tunnel."); 85195699Srwatson#endif /* IPSEC */ 86195699Srwatson 87155179Sandre/* 88155179Sandre * Check if we have to jump over firewall processing for this packet. 89155179Sandre * Called from ip_input(). 90155179Sandre * 1 = jump over firewall, 0 = packet goes through firewall. 91155179Sandre */ 92155179Sandreint 93171732Sbzip_ipsec_filtertunnel(struct mbuf *m) 94155179Sandre{ 95230442Sbz#ifdef IPSEC 96192648Sbz 97155179Sandre /* 98222845Sbz * Bypass packet filtering for packets previously handled by IPsec. 99155179Sandre */ 100192648Sbz if (!V_ip4_ipsec_filtertunnel && 101192648Sbz m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 102155179Sandre return 1; 103155179Sandre#endif 104155179Sandre return 0; 105155179Sandre} 106155179Sandre 107155179Sandre/* 108155179Sandre * Check if this packet has an active SA and needs to be dropped instead 109155179Sandre * of forwarded. 110155179Sandre * Called from ip_input(). 111155179Sandre * 1 = drop packet, 0 = forward packet. 112155179Sandre */ 113155179Sandreint 114155179Sandreip_ipsec_fwd(struct mbuf *m) 115155179Sandre{ 116171167Sgnn#ifdef IPSEC 117155179Sandre struct m_tag *mtag; 118155179Sandre struct tdb_ident *tdbi; 119155179Sandre struct secpolicy *sp; 120241686Sandre int error; 121171133Sgnn 122155179Sandre mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 123155179Sandre if (mtag != NULL) { 124155179Sandre tdbi = (struct tdb_ident *)(mtag + 1); 125155179Sandre sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 126155179Sandre } else { 127155179Sandre sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 128155179Sandre IP_FORWARDING, &error); 129155179Sandre } 130155179Sandre if (sp == NULL) { /* NB: can happen if error */ 131155179Sandre /*XXX error stat???*/ 132155179Sandre DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 133155179Sandre return 1; 134155179Sandre } 135155179Sandre 136155179Sandre /* 137155179Sandre * Check security policy against packet attributes. 138155179Sandre */ 139155179Sandre error = ipsec_in_reject(sp, m); 140155179Sandre KEY_FREESP(&sp); 141155179Sandre if (error) { 142190951Srwatson IPSTAT_INC(ips_cantforward); 143155179Sandre return 1; 144155179Sandre } 145171167Sgnn#endif /* IPSEC */ 146155179Sandre return 0; 147155179Sandre} 148155179Sandre 149155179Sandre/* 150155179Sandre * Check if protocol type doesn't have a further header and do IPSEC 151155179Sandre * decryption or reject right now. Protocols with further headers get 152155179Sandre * their IPSEC treatment within the protocol specific processing. 153155179Sandre * Called from ip_input(). 154155179Sandre * 1 = drop packet, 0 = continue processing packet. 155155179Sandre */ 156155179Sandreint 157155179Sandreip_ipsec_input(struct mbuf *m) 158155179Sandre{ 159195699Srwatson#ifdef IPSEC 160155179Sandre struct ip *ip = mtod(m, struct ip *); 161155179Sandre struct m_tag *mtag; 162155179Sandre struct tdb_ident *tdbi; 163155179Sandre struct secpolicy *sp; 164241686Sandre int error; 165155179Sandre /* 166155179Sandre * enforce IPsec policy checking if we are seeing last header. 167155179Sandre * note that we do not visit this with protocols with pcb layer 168155179Sandre * code - like udp/tcp/raw ip. 169155179Sandre */ 170155179Sandre if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 171155179Sandre /* 172155179Sandre * Check if the packet has already had IPsec processing 173155179Sandre * done. If so, then just pass it along. This tag gets 174155179Sandre * set during AH, ESP, etc. input handling, before the 175155179Sandre * packet is returned to the ip input queue for delivery. 176155179Sandre */ 177155179Sandre mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 178155179Sandre if (mtag != NULL) { 179155179Sandre tdbi = (struct tdb_ident *)(mtag + 1); 180155179Sandre sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 181155179Sandre } else { 182155179Sandre sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 183155179Sandre IP_FORWARDING, &error); 184155179Sandre } 185155179Sandre if (sp != NULL) { 186155179Sandre /* 187155179Sandre * Check security policy against packet attributes. 188155179Sandre */ 189155179Sandre error = ipsec_in_reject(sp, m); 190155179Sandre KEY_FREESP(&sp); 191155179Sandre } else { 192155179Sandre /* XXX error stat??? */ 193155179Sandre error = EINVAL; 194155179Sandre DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 195155179Sandre return 1; 196155179Sandre } 197155179Sandre if (error) 198155179Sandre return 1; 199155179Sandre } 200171167Sgnn#endif /* IPSEC */ 201155179Sandre return 0; 202155179Sandre} 203155179Sandre 204155179Sandre/* 205155179Sandre * Compute the MTU for a forwarded packet that gets IPSEC encapsulated. 206155179Sandre * Called from ip_forward(). 207155179Sandre * Returns MTU suggestion for ICMP needfrag reply. 208155179Sandre */ 209155179Sandreint 210178029Sbzip_ipsec_mtu(struct mbuf *m, int mtu) 211155179Sandre{ 212155179Sandre /* 213155179Sandre * If the packet is routed over IPsec tunnel, tell the 214155179Sandre * originator the tunnel MTU. 215155179Sandre * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 216155179Sandre * XXX quickhack!!! 217155179Sandre */ 218155179Sandre struct secpolicy *sp = NULL; 219155179Sandre int ipsecerror; 220155179Sandre int ipsechdr; 221155179Sandre struct route *ro; 222155179Sandre sp = ipsec_getpolicybyaddr(m, 223155179Sandre IPSEC_DIR_OUTBOUND, 224155179Sandre IP_FORWARDING, 225155179Sandre &ipsecerror); 226155179Sandre if (sp != NULL) { 227155179Sandre /* count IPsec header size */ 228188306Sbz ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL); 229155179Sandre 230155179Sandre /* 231155179Sandre * find the correct route for outer IPv4 232155179Sandre * header, compute tunnel MTU. 233155179Sandre */ 234155179Sandre if (sp->req != NULL && 235155179Sandre sp->req->sav != NULL && 236155179Sandre sp->req->sav->sah != NULL) { 237214250Sbz ro = &sp->req->sav->sah->route_cache.sa_route; 238155179Sandre if (ro->ro_rt && ro->ro_rt->rt_ifp) { 239263478Sglebius mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu : 240155179Sandre ro->ro_rt->rt_ifp->if_mtu; 241155179Sandre mtu -= ipsechdr; 242155179Sandre } 243155179Sandre } 244155179Sandre KEY_FREESP(&sp); 245155179Sandre } 246155179Sandre return mtu; 247155179Sandre} 248155179Sandre 249155179Sandre/* 250155179Sandre * 251155179Sandre * Called from ip_output(). 252155179Sandre * 1 = drop packet, 0 = continue processing packet, 253171167Sgnn * -1 = packet was reinjected and stop processing packet 254155179Sandre */ 255155179Sandreint 256199102Straszip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error) 257155179Sandre{ 258171167Sgnn#ifdef IPSEC 259155179Sandre struct secpolicy *sp = NULL; 260155179Sandre struct tdb_ident *tdbi; 261155179Sandre struct m_tag *mtag; 262155179Sandre /* 263155179Sandre * Check the security policy (SP) for the packet and, if 264155179Sandre * required, do IPsec-related processing. There are two 265155179Sandre * cases here; the first time a packet is sent through 266155179Sandre * it will be untagged and handled by ipsec4_checkpolicy. 267155179Sandre * If the packet is resubmitted to ip_output (e.g. after 268155179Sandre * AH, ESP, etc. processing), there will be a tag to bypass 269155179Sandre * the lookup and related policy checking. 270155179Sandre */ 271155179Sandre mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 272155179Sandre if (mtag != NULL) { 273155179Sandre tdbi = (struct tdb_ident *)(mtag + 1); 274155179Sandre sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND); 275155179Sandre if (sp == NULL) 276155179Sandre *error = -EINVAL; /* force silent drop */ 277155179Sandre m_tag_delete(*m, mtag); 278155179Sandre } else { 279155179Sandre sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, 280155179Sandre error, inp); 281155179Sandre } 282155179Sandre /* 283155179Sandre * There are four return cases: 284155179Sandre * sp != NULL apply IPsec policy 285155179Sandre * sp == NULL, error == 0 no IPsec handling needed 286155179Sandre * sp == NULL, error == -EINVAL discard packet w/o error 287155179Sandre * sp == NULL, error != 0 discard packet, report error 288155179Sandre */ 289155179Sandre if (sp != NULL) { 290155179Sandre /* Loop detection, check if ipsec processing already done */ 291155179Sandre KASSERT(sp->req != NULL, ("ip_output: no ipsec request")); 292155179Sandre for (mtag = m_tag_first(*m); mtag != NULL; 293155179Sandre mtag = m_tag_next(*m, mtag)) { 294155179Sandre if (mtag->m_tag_cookie != MTAG_ABI_COMPAT) 295155179Sandre continue; 296155179Sandre if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && 297155179Sandre mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) 298155179Sandre continue; 299155179Sandre /* 300155179Sandre * Check if policy has an SA associated with it. 301155179Sandre * This can happen when an SP has yet to acquire 302155179Sandre * an SA; e.g. on first reference. If it occurs, 303155179Sandre * then we let ipsec4_process_packet do its thing. 304155179Sandre */ 305155179Sandre if (sp->req->sav == NULL) 306155179Sandre break; 307155179Sandre tdbi = (struct tdb_ident *)(mtag + 1); 308155179Sandre if (tdbi->spi == sp->req->sav->spi && 309155179Sandre tdbi->proto == sp->req->sav->sah->saidx.proto && 310155179Sandre bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst, 311155179Sandre sizeof (union sockaddr_union)) == 0) { 312155179Sandre /* 313155179Sandre * No IPsec processing is needed, free 314155179Sandre * reference to SP. 315155179Sandre * 316155179Sandre * NB: null pointer to avoid free at 317155179Sandre * done: below. 318155179Sandre */ 319155179Sandre KEY_FREESP(&sp), sp = NULL; 320155179Sandre goto done; 321155179Sandre } 322155179Sandre } 323155179Sandre 324155179Sandre /* 325155179Sandre * Do delayed checksums now because we send before 326155179Sandre * this is done in the normal processing path. 327155179Sandre */ 328155179Sandre if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 329155179Sandre in_delayed_cksum(*m); 330155179Sandre (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 331155179Sandre } 332188066Srrs#ifdef SCTP 333188066Srrs if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) { 334241913Sglebius struct ip *ip = mtod(*m, struct ip *); 335241913Sglebius 336205104Srrs sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2)); 337188066Srrs (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP; 338188066Srrs } 339188066Srrs#endif 340155179Sandre 341155179Sandre /* NB: callee frees mbuf */ 342155179Sandre *error = ipsec4_process_packet(*m, sp->req, *flags, 0); 343177175Sbz if (*error == EJUSTRETURN) { 344177175Sbz /* 345177175Sbz * We had a SP with a level of 'use' and no SA. We 346177175Sbz * will just continue to process the packet without 347177175Sbz * IPsec processing and return without error. 348177175Sbz */ 349177175Sbz *error = 0; 350177175Sbz goto done; 351177175Sbz } 352155179Sandre /* 353155179Sandre * Preserve KAME behaviour: ENOENT can be returned 354155179Sandre * when an SA acquire is in progress. Don't propagate 355155179Sandre * this to user-level; it confuses applications. 356155179Sandre * 357155179Sandre * XXX this will go away when the SADB is redone. 358155179Sandre */ 359155179Sandre if (*error == ENOENT) 360155179Sandre *error = 0; 361155179Sandre goto reinjected; 362155179Sandre } else { /* sp == NULL */ 363155179Sandre 364155179Sandre if (*error != 0) { 365155179Sandre /* 366155179Sandre * Hack: -EINVAL is used to signal that a packet 367155179Sandre * should be silently discarded. This is typically 368155179Sandre * because we asked key management for an SA and 369155179Sandre * it was delayed (e.g. kicked up to IKE). 370155179Sandre */ 371155179Sandre if (*error == -EINVAL) 372155179Sandre *error = 0; 373155179Sandre goto bad; 374155179Sandre } else { 375155179Sandre /* No IPsec processing for this packet. */ 376155179Sandre } 377155179Sandre } 378155179Sandredone: 379155179Sandre if (sp != NULL) 380155179Sandre KEY_FREESP(&sp); 381155179Sandre return 0; 382155179Sandrereinjected: 383155179Sandre if (sp != NULL) 384155179Sandre KEY_FREESP(&sp); 385155179Sandre return -1; 386155179Sandrebad: 387155179Sandre if (sp != NULL) 388155179Sandre KEY_FREESP(&sp); 389155179Sandre return 1; 390171167Sgnn#endif /* IPSEC */ 391155179Sandre return 0; 392155179Sandre} 393