1 /* $FreeBSD: src/sys/netipsec/ipsec_input.c,v 1.2.4.2 2003/03/28 20:32:53 sam Exp $ */
2 /* $OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $ */
4 * The authors of this code are John Ioannidis (ji@tla.org),
5 * Angelos D. Keromytis (kermit@csd.uch.gr) and
6 * Niels Provos (provos@physnet.uni-hamburg.de).
8 * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
12 * by Angelos D. Keromytis.
14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
17 * Additional features in 1999 by Angelos D. Keromytis.
19 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
20 * Angelos D. Keromytis and Niels Provos.
21 * Copyright (c) 2001, Angelos D. Keromytis.
23 * Permission to use, copy, and modify this software with or without fee
24 * is hereby granted, provided that this entire notice is included in
25 * all copies of any software which is or includes a copy or
26 * modification of this software.
27 * You may use this code under the GNU public license if you so wish. Please
28 * contribute changes back to the authors under this freer than GPL license
29 * so that we may further the use of strong encryption without limitations to
32 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
33 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
34 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
35 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
40 * IPsec input processing.
44 #include "opt_inet6.h"
45 #include "opt_ipsec.h"
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/malloc.h>
51 #include <sys/domain.h>
52 #include <sys/protosw.h>
53 #include <sys/socket.h>
54 #include <sys/errno.h>
55 #include <sys/syslog.h>
58 #include <net/route.h>
59 #include <net/netisr.h>
61 #include <netinet/in.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/ip.h>
64 #include <netinet/ip_var.h>
65 #include <netinet/in_var.h>
67 #include <netinet/ip6.h>
69 #include <netinet6/ip6_var.h>
71 #include <netinet/in_pcb.h>
73 #include <netinet/icmp6.h>
76 #include <netipsec/ipsec.h>
78 #include <netipsec/ipsec6.h>
80 #include <netipsec/ah_var.h>
81 #include <netipsec/esp.h>
82 #include <netipsec/esp_var.h>
83 #include <netipsec/ipcomp_var.h>
85 #include <netipsec/key.h>
86 #include <netipsec/keydb.h>
88 #include <netipsec/xform.h>
89 #include <netinet6/ip6protosw.h>
91 #include <machine/in_cksum.h>
92 #include <machine/stdarg.h>
94 #include <net/net_osdep.h>
96 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
97 (p) == IPPROTO_AH ? (y)++ : (z)++)
100 * ipsec_common_input gets called when an IPsec-protected packet
101 * is received by IPv4 or IPv6. It's job is to find the right SA
102 # and call the appropriate transform. The transform callback
103 * takes care of further processing (like ingress filtering).
106 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
108 union sockaddr_union dst_address;
109 struct secasvar *sav;
113 IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input,
114 ipcompstat.ipcomps_input);
116 KASSERT(m != NULL, ("ipsec_common_input: null packet"));
118 if ((sproto == IPPROTO_ESP && !esp_enable) ||
119 (sproto == IPPROTO_AH && !ah_enable) ||
120 (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) {
122 IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops,
123 ipcompstat.ipcomps_pdrops);
127 if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
129 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
130 ipcompstat.ipcomps_hdrops);
131 DPRINTF(("ipsec_common_input: packet too small\n"));
135 /* Retrieve the SPI from the relevant IPsec header */
136 if (sproto == IPPROTO_ESP)
137 m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
138 else if (sproto == IPPROTO_AH)
139 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
141 else if (sproto == IPPROTO_IPCOMP) {
143 m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
145 spi = ntohl(htons(cpi));
149 * Find the SA and (indirectly) call the appropriate
150 * kernel crypto routine. The resulting mbuf chain is a valid
151 * IP packet ready to go through input processing.
153 bzero(&dst_address, sizeof (dst_address));
154 dst_address.sa.sa_family = af;
158 dst_address.sin.sin_len = sizeof(struct sockaddr_in);
159 m_copydata(m, offsetof(struct ip, ip_dst),
160 sizeof(struct in_addr),
161 (caddr_t) &dst_address.sin.sin_addr);
166 dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
167 m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
168 sizeof(struct in6_addr),
169 (caddr_t) &dst_address.sin6.sin6_addr);
173 DPRINTF(("ipsec_common_input: unsupported protocol "
176 IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf,
177 ipcompstat.ipcomps_nopf);
183 /* NB: only pass dst since key_allocsa follows RFC2401 */
184 sav = KEY_ALLOCSA(&dst_address, sproto, spi);
186 DPRINTF(("ipsec_common_input: no key association found for"
188 ipsec_address(&dst_address),
189 (u_long) ntohl(spi), sproto));
190 IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb,
191 ipcompstat.ipcomps_notdb);
197 if (sav->tdb_xform == NULL) {
198 DPRINTF(("ipsec_common_input: attempted to use uninitialized"
200 ipsec_address(&dst_address),
201 (u_long) ntohl(spi), sproto));
202 IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform,
203 ipcompstat.ipcomps_noxform);
211 * Call appropriate transform and return -- callback takes care of
214 error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
222 * Common input handler for IPv4 AH, ESP, and IPCOMP.
225 ipsec4_common_input(struct mbuf *m, ...)
231 off = va_arg(ap, int);
232 nxt = va_arg(ap, int);
235 return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
240 * IPsec input callback for INET protocols.
241 * This routine is called as the transform callback.
242 * Takes care of filtering and other sanity checks on
243 * the processed packet.
246 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
247 int skip, int protoff, struct m_tag *mt)
249 int prot, af, sproto;
252 struct tdb_ident *tdbi;
253 struct secasindex *saidx;
256 SPLASSERT(net, "ipsec4_common_input_cb");
258 KASSERT(m != NULL, ("ipsec4_common_input_cb: null mbuf"));
259 KASSERT(sav != NULL, ("ipsec4_common_input_cb: null SA"));
260 KASSERT(sav->sah != NULL, ("ipsec4_common_input_cb: null SAH"));
261 saidx = &sav->sah->saidx;
262 af = saidx->dst.sa.sa_family;
263 KASSERT(af == AF_INET, ("ipsec4_common_input_cb: unexpected af %u",af));
264 sproto = saidx->proto;
265 KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
266 sproto == IPPROTO_IPCOMP,
267 ("ipsec4_common_input_cb: unexpected security protocol %u",
272 DPRINTF(("ipsec4_common_input_cb: null mbuf"));
273 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
274 ipcompstat.ipcomps_badkcr);
280 /* Fix IPv4 header */
281 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
282 DPRINTF(("ipsec4_common_input_cb: processing failed "
284 ipsec_address(&sav->sah->saidx.dst),
285 (u_long) ntohl(sav->spi)));
286 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
287 ipcompstat.ipcomps_hdrops);
292 ip = mtod(m, struct ip *);
293 ip->ip_len = htons(m->m_pkthdr.len);
294 ip->ip_off = htons(ip->ip_off);
296 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
298 ip = mtod(m, struct ip *);
302 /* IP-in-IP encapsulation */
303 if (prot == IPPROTO_IPIP) {
306 /* ipn will now contain the inner IPv4 header */
307 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
311 /* XXX PROXY address isn't recorded in SAH */
313 * Check that the inner source address is the same as
314 * the proxy address, if available.
316 if ((saidx->proxy.sa.sa_family == AF_INET &&
317 saidx->proxy.sin.sin_addr.s_addr !=
320 saidx->proxy.sin.sin_addr.s_addr) ||
321 (saidx->proxy.sa.sa_family != AF_INET &&
322 saidx->proxy.sa.sa_family != 0)) {
324 DPRINTF(("ipsec4_common_input_cb: inner "
325 "source address %s doesn't correspond to "
326 "expected proxy source %s, SA %s/%08lx\n",
327 inet_ntoa4(ipn.ip_src),
328 ipsp_address(saidx->proxy),
329 ipsp_address(saidx->dst),
330 (u_long) ntohl(sav->spi)));
332 IPSEC_ISTAT(sproto, espstat.esps_pdrops,
334 ipcompstat.ipcomps_pdrops);
341 /* IPv6-in-IP encapsulation. */
342 if (prot == IPPROTO_IPV6) {
345 /* ip6n will now contain the inner IPv6 header. */
346 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
351 * Check that the inner source address is the same as
352 * the proxy address, if available.
354 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
355 !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
356 !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
357 &saidx->proxy.sin6.sin6_addr)) ||
358 (saidx->proxy.sa.sa_family != AF_INET6 &&
359 saidx->proxy.sa.sa_family != 0)) {
361 DPRINTF(("ipsec4_common_input_cb: inner "
362 "source address %s doesn't correspond to "
363 "expected proxy source %s, SA %s/%08lx\n",
364 ip6_sprintf(&ip6n.ip6_src),
365 ipsec_address(&saidx->proxy),
366 ipsec_address(&saidx->dst),
367 (u_long) ntohl(sav->spi)));
369 IPSEC_ISTAT(sproto, espstat.esps_pdrops,
371 ipcompstat.ipcomps_pdrops);
380 * Record what we've done to the packet (under what SA it was
381 * processed). If we've been passed an mtag, it means the packet
382 * was already processed by an ethernet/crypto combo card and
383 * thus has a tag attached with all the right information, but
384 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
385 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
387 if (mt == NULL && sproto != IPPROTO_IPCOMP) {
388 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
389 sizeof(struct tdb_ident), M_NOWAIT);
391 DPRINTF(("ipsec4_common_input_cb: failed to get tag\n"));
392 IPSEC_ISTAT(sproto, espstat.esps_hdrops,
393 ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
398 tdbi = (struct tdb_ident *)(mtag + 1);
399 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
400 tdbi->proto = sproto;
401 tdbi->spi = sav->spi;
403 m_tag_prepend(m, mtag);
405 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
406 /* XXX do we need to mark m_flags??? */
409 key_sa_recordxfer(sav, m); /* record data transfer */
412 * Re-dispatch via software interrupt.
414 if (!IF_HANDOFF(&ipintrq, m, NULL)) {
415 IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
416 ipcompstat.ipcomps_qfull);
418 DPRINTF(("ipsec4_common_input_cb: queue full; "
419 "proto %u packet dropped\n", sproto));
422 schednetisr(NETISR_IP);
431 /* IPv6 AH wrapper. */
433 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
439 if (*offp < sizeof(struct ip6_hdr)) {
440 DPRINTF(("ipsec6_common_input: bad offset %u\n", *offp));
442 } else if (*offp == sizeof(struct ip6_hdr)) {
443 protoff = offsetof(struct ip6_hdr, ip6_nxt);
445 /* Chase down the header chain... */
446 protoff = sizeof(struct ip6_hdr);
450 m_copydata(*mp, protoff, sizeof(ip6e),
453 if (ip6e.ip6e_nxt == IPPROTO_AH)
454 l = (ip6e.ip6e_len + 2) << 2;
456 l = (ip6e.ip6e_len + 1) << 3;
457 KASSERT(l > 0, ("ah6_input: l went zero or negative"));
458 } while (protoff + l < *offp);
460 /* Malformed packet check */
461 if (protoff + l != *offp) {
462 DPRINTF(("ipsec6_common_input: bad packet header chain, "
463 "protoff %u, l %u, off %u\n", protoff, l, *offp));
464 IPSEC_ISTAT(proto, espstat.esps_hdrops,
466 ipcompstat.ipcomps_hdrops);
471 protoff += offsetof(struct ip6_ext, ip6e_nxt);
473 (void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
478 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
480 if (sa->sa_family != AF_INET6 ||
481 sa->sa_len != sizeof(struct sockaddr_in6))
483 if ((unsigned)cmd >= PRC_NCMDS)
486 /* if the parameter is from icmp6, decode it. */
488 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
489 struct mbuf *m = ip6cp->ip6c_m;
490 int off = ip6cp->ip6c_off;
492 struct ip6ctlparam ip6cp1;
495 * Notify the error to all possible sockets via pfctlinput2.
496 * Since the upper layer information (such as protocol type,
497 * source and destination ports) is embedded in the encrypted
498 * data and might have been cut, we can't directly call
499 * an upper layer ctlinput function. However, the pcbnotify
500 * function will consider source and destination addresses
501 * as well as the flow info value, and may be able to find
502 * some PCB that should be notified.
503 * Although pfctlinput2 will call esp6_ctlinput(), there is
504 * no possibility of an infinite loop of function calls,
505 * because we don't pass the inner IPv6 header.
507 bzero(&ip6cp1, sizeof(ip6cp1));
508 ip6cp1.ip6c_src = ip6cp->ip6c_src;
509 pfctlinput2(cmd, sa, (void *)&ip6cp1);
512 * Then go to special cases that need ESP header information.
513 * XXX: We assume that when ip6 is non NULL,
514 * M and OFF are valid.
517 if (cmd == PRC_MSGSIZE) {
518 struct secasvar *sav;
522 /* check header length before using m_copydata */
523 if (m->m_pkthdr.len < off + sizeof (struct esp))
525 m_copydata(m, off + offsetof(struct esp, esp_spi),
526 sizeof(u_int32_t), (caddr_t) &spi);
528 * Check to see if we have a valid SA corresponding to
529 * the address in the ICMP message payload.
531 sav = KEY_ALLOCSA((union sockaddr_union *)sa,
533 valid = (sav != NULL);
537 /* XXX Further validation? */
540 * Depending on whether the SA is "valid" and
541 * routing table size (mtudisc_{hi,lo}wat), we will:
542 * - recalcurate the new MTU and create the
543 * corresponding routing entry, or
544 * - ignore the MTU change notification.
546 icmp6_mtudisc_update(ip6cp, valid);
549 /* we normally notify any pcb here */
553 extern struct ip6protosw inet6sw[];
554 extern u_char ip6_protox[];
557 * IPsec input callback, called by the transform callback. Takes care of
558 * filtering and other sanity checks on the processed packet.
561 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
564 int prot, af, sproto;
567 struct tdb_ident *tdbi;
568 struct secasindex *saidx;
573 KASSERT(m != NULL, ("ipsec6_common_input_cb: null mbuf"));
574 KASSERT(sav != NULL, ("ipsec6_common_input_cb: null SA"));
575 KASSERT(sav->sah != NULL, ("ipsec6_common_input_cb: null SAH"));
576 saidx = &sav->sah->saidx;
577 af = saidx->dst.sa.sa_family;
578 KASSERT(af == AF_INET6,
579 ("ipsec6_common_input_cb: unexpected af %u", af));
580 sproto = saidx->proto;
581 KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
582 sproto == IPPROTO_IPCOMP,
583 ("ipsec6_common_input_cb: unexpected security protocol %u",
588 DPRINTF(("ipsec4_common_input_cb: null mbuf"));
589 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
590 ipcompstat.ipcomps_badkcr);
595 /* Fix IPv6 header */
596 if (m->m_len < sizeof(struct ip6_hdr) &&
597 (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
599 DPRINTF(("ipsec_common_input_cb: processing failed "
600 "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst),
601 (u_long) ntohl(sav->spi)));
603 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
604 ipcompstat.ipcomps_hdrops);
609 ip6 = mtod(m, struct ip6_hdr *);
610 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
613 m_copydata(m, protoff, 1, (unsigned char *) &prot);
616 /* IP-in-IP encapsulation */
617 if (prot == IPPROTO_IPIP) {
620 /* ipn will now contain the inner IPv4 header */
621 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
625 * Check that the inner source address is the same as
626 * the proxy address, if available.
628 if ((saidx->proxy.sa.sa_family == AF_INET &&
629 saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
630 ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
631 (saidx->proxy.sa.sa_family != AF_INET &&
632 saidx->proxy.sa.sa_family != 0)) {
634 DPRINTF(("ipsec_common_input_cb: inner "
635 "source address %s doesn't correspond to "
636 "expected proxy source %s, SA %s/%08lx\n",
637 inet_ntoa4(ipn.ip_src),
638 ipsec_address(&saidx->proxy),
639 ipsec_address(&saidx->dst),
640 (u_long) ntohl(sav->spi)));
642 IPSEC_ISTATsproto, (espstat.esps_pdrops,
643 ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
651 /* IPv6-in-IP encapsulation */
652 if (prot == IPPROTO_IPV6) {
655 /* ip6n will now contain the inner IPv6 header. */
656 m_copydata(m, skip, sizeof(struct ip6_hdr),
661 * Check that the inner source address is the same as
662 * the proxy address, if available.
664 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
665 !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
666 !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
667 &saidx->proxy.sin6.sin6_addr)) ||
668 (saidx->proxy.sa.sa_family != AF_INET6 &&
669 saidx->proxy.sa.sa_family != 0)) {
671 DPRINTF(("ipsec_common_input_cb: inner "
672 "source address %s doesn't correspond to "
673 "expected proxy source %s, SA %s/%08lx\n",
674 ip6_sprintf(&ip6n.ip6_src),
675 ipsec_address(&saidx->proxy),
676 ipsec_address(&saidx->dst),
677 (u_long) ntohl(sav->spi)));
679 IPSEC_ISTAT(sproto, espstat.esps_pdrops,
680 ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
688 * Record what we've done to the packet (under what SA it was
689 * processed). If we've been passed an mtag, it means the packet
690 * was already processed by an ethernet/crypto combo card and
691 * thus has a tag attached with all the right information, but
692 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
693 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
695 if (mt == NULL && sproto != IPPROTO_IPCOMP) {
696 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
697 sizeof(struct tdb_ident), M_NOWAIT);
699 DPRINTF(("ipsec_common_input_cb: failed to "
701 IPSEC_ISTAT(sproto, espstat.esps_hdrops,
702 ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
707 tdbi = (struct tdb_ident *)(mtag + 1);
708 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
709 tdbi->proto = sproto;
710 tdbi->spi = sav->spi;
712 m_tag_prepend(m, mtag);
714 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
715 /* XXX do we need to mark m_flags??? */
718 key_sa_recordxfer(sav, m);
720 /* Retrieve new protocol */
721 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
724 * See the end of ip6_input for this logic.
725 * IPPROTO_IPV[46] case will be processed just like other ones
729 while (nxt != IPPROTO_DONE) {
730 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
731 ip6stat.ip6s_toomanyhdr++;
737 * Protection against faulty packet - there should be
738 * more sanity checks in header chain processing.
740 if (m->m_pkthdr.len < skip) {
741 ip6stat.ip6s_tooshort++;
742 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
747 * Enforce IPsec policy checking if we are seeing last header.
748 * note that we do not visit this with protocols with pcb layer
749 * code - like udp/tcp/raw ip.
751 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
752 ipsec6_in_reject(m, NULL)) {
756 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);