xref: /freebsd-13.1/sys/netipsec/ipsec_input.c (revision 1ebe8e0f)
1 /*	$OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $	*/
2 /*-
3  * The authors of this code are John Ioannidis ([email protected]),
4  * Angelos D. Keromytis ([email protected]) and
5  * Niels Provos ([email protected]).
6  *
7  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
8  * in November 1995.
9  *
10  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
11  * by Angelos D. Keromytis.
12  *
13  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
14  * and Niels Provos.
15  *
16  * Additional features in 1999 by Angelos D. Keromytis.
17  *
18  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
19  * Angelos D. Keromytis and Niels Provos.
20  * Copyright (c) 2001, Angelos D. Keromytis.
21  * Copyright (c) 2016 Andrey V. Elsukov <[email protected]>
22  *
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
30  * all.
31  *
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
36  * PURPOSE.
37  */
38 
39 /*
40  * IPsec input processing.
41  */
42 
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45 
46 #include "opt_inet.h"
47 #include "opt_inet6.h"
48 #include "opt_ipsec.h"
49 
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/malloc.h>
53 #include <sys/mbuf.h>
54 #include <sys/domain.h>
55 #include <sys/protosw.h>
56 #include <sys/socket.h>
57 #include <sys/errno.h>
58 #include <sys/hhook.h>
59 #include <sys/syslog.h>
60 
61 #include <net/if.h>
62 #include <net/if_var.h>
63 #include <net/if_enc.h>
64 #include <net/netisr.h>
65 #include <net/vnet.h>
66 
67 #include <netinet/in.h>
68 #include <netinet/in_systm.h>
69 #include <netinet/ip.h>
70 #include <netinet/ip_var.h>
71 #include <netinet/in_var.h>
72 
73 #include <netinet/ip6.h>
74 #ifdef INET6
75 #include <netinet6/ip6_var.h>
76 #endif
77 #include <netinet/in_pcb.h>
78 #ifdef INET6
79 #include <netinet/icmp6.h>
80 #endif
81 
82 #include <netipsec/ipsec.h>
83 #ifdef INET6
84 #include <netipsec/ipsec6.h>
85 #endif
86 #include <netipsec/ah_var.h>
87 #include <netipsec/esp.h>
88 #include <netipsec/esp_var.h>
89 #include <netipsec/ipcomp_var.h>
90 
91 #include <netipsec/key.h>
92 #include <netipsec/keydb.h>
93 #include <netipsec/key_debug.h>
94 
95 #include <netipsec/xform.h>
96 #include <netinet6/ip6protosw.h>
97 
98 #include <machine/in_cksum.h>
99 #include <machine/stdarg.h>
100 
101 #define	IPSEC_ISTAT(proto, name)	do {	\
102 	if ((proto) == IPPROTO_ESP)		\
103 		ESPSTAT_INC(esps_##name);	\
104 	else if ((proto) == IPPROTO_AH)		\
105 		AHSTAT_INC(ahs_##name);		\
106 	else					\
107 		IPCOMPSTAT_INC(ipcomps_##name);	\
108 } while (0)
109 
110 /*
111  * ipsec_common_input gets called when an IPsec-protected packet
112  * is received by IPv4 or IPv6.  Its job is to find the right SA
113  * and call the appropriate transform.  The transform callback
114  * takes care of further processing (like ingress filtering).
115  */
116 static int
ipsec_common_input(struct mbuf * m,int skip,int protoff,int af,int sproto)117 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
118 {
119 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
120 	union sockaddr_union dst_address;
121 	struct secasvar *sav;
122 	uint32_t spi;
123 	int error;
124 
125 	IPSEC_ISTAT(sproto, input);
126 
127 	IPSEC_ASSERT(m != NULL, ("null packet"));
128 
129 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
130 		sproto == IPPROTO_IPCOMP,
131 		("unexpected security protocol %u", sproto));
132 
133 	if ((sproto == IPPROTO_ESP && !V_esp_enable) ||
134 	    (sproto == IPPROTO_AH && !V_ah_enable) ||
135 	    (sproto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
136 		m_freem(m);
137 		IPSEC_ISTAT(sproto, pdrops);
138 		return EOPNOTSUPP;
139 	}
140 
141 	if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
142 		m_freem(m);
143 		IPSEC_ISTAT(sproto, hdrops);
144 		DPRINTF(("%s: packet too small\n", __func__));
145 		return EINVAL;
146 	}
147 
148 	/* Retrieve the SPI from the relevant IPsec header */
149 	if (sproto == IPPROTO_ESP)
150 		m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
151 	else if (sproto == IPPROTO_AH)
152 		m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
153 		    (caddr_t) &spi);
154 	else if (sproto == IPPROTO_IPCOMP) {
155 		u_int16_t cpi;
156 		m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
157 		    (caddr_t) &cpi);
158 		spi = ntohl(htons(cpi));
159 	}
160 
161 	/*
162 	 * Find the SA and (indirectly) call the appropriate
163 	 * kernel crypto routine. The resulting mbuf chain is a valid
164 	 * IP packet ready to go through input processing.
165 	 */
166 	bzero(&dst_address, sizeof (dst_address));
167 	dst_address.sa.sa_family = af;
168 	switch (af) {
169 #ifdef INET
170 	case AF_INET:
171 		dst_address.sin.sin_len = sizeof(struct sockaddr_in);
172 		m_copydata(m, offsetof(struct ip, ip_dst),
173 		    sizeof(struct in_addr),
174 		    (caddr_t) &dst_address.sin.sin_addr);
175 		break;
176 #endif /* INET */
177 #ifdef INET6
178 	case AF_INET6:
179 		dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
180 		m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
181 		    sizeof(struct in6_addr),
182 		    (caddr_t) &dst_address.sin6.sin6_addr);
183 		/* We keep addresses in SADB without embedded scope id */
184 		if (IN6_IS_SCOPE_LINKLOCAL(&dst_address.sin6.sin6_addr)) {
185 			/* XXX: sa6_recoverscope() */
186 			dst_address.sin6.sin6_scope_id =
187 			    ntohs(dst_address.sin6.sin6_addr.s6_addr16[1]);
188 			dst_address.sin6.sin6_addr.s6_addr16[1] = 0;
189 		}
190 		break;
191 #endif /* INET6 */
192 	default:
193 		DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
194 		m_freem(m);
195 		IPSEC_ISTAT(sproto, nopf);
196 		return EPFNOSUPPORT;
197 	}
198 
199 	/* NB: only pass dst since key_allocsa follows RFC2401 */
200 	sav = key_allocsa(&dst_address, sproto, spi);
201 	if (sav == NULL) {
202 		DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
203 		    __func__, ipsec_address(&dst_address, buf, sizeof(buf)),
204 		    (u_long) ntohl(spi), sproto));
205 		IPSEC_ISTAT(sproto, notdb);
206 		m_freem(m);
207 		return ENOENT;
208 	}
209 
210 	if (sav->tdb_xform == NULL) {
211 		DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
212 		    __func__, ipsec_address(&dst_address, buf, sizeof(buf)),
213 		    (u_long) ntohl(spi), sproto));
214 		IPSEC_ISTAT(sproto, noxform);
215 		key_freesav(&sav);
216 		m_freem(m);
217 		return ENXIO;
218 	}
219 
220 	/*
221 	 * Call appropriate transform and return -- callback takes care of
222 	 * everything else.
223 	 */
224 	error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
225 	return (error);
226 }
227 
228 #ifdef INET
229 extern struct protosw inetsw[];
230 
231 /*
232  * IPSEC_INPUT() method implementation for IPv4.
233  *  0 - Permitted by inbound security policy for further processing.
234  *  EACCES - Forbidden by inbound security policy.
235  *  EINPROGRESS - consumed by IPsec.
236  */
237 int
ipsec4_input(struct mbuf * m,int offset,int proto)238 ipsec4_input(struct mbuf *m, int offset, int proto)
239 {
240 
241 	switch (proto) {
242 	case IPPROTO_AH:
243 	case IPPROTO_ESP:
244 	case IPPROTO_IPCOMP:
245 		/* Do inbound IPsec processing for AH/ESP/IPCOMP */
246 		ipsec_common_input(m, offset,
247 		    offsetof(struct ip, ip_p), AF_INET, proto);
248 		return (EINPROGRESS); /* mbuf consumed by IPsec */
249 	default:
250 		/*
251 		 * Protocols with further headers get their IPsec treatment
252 		 * within the protocol specific processing.
253 		 */
254 		if ((inetsw[ip_protox[proto]].pr_flags & PR_LASTHDR) == 0)
255 			return (0);
256 		/* FALLTHROUGH */
257 	};
258 	/*
259 	 * Enforce IPsec policy checking if we are seeing last header.
260 	 */
261 	if (ipsec4_in_reject(m, NULL) != 0) {
262 		/* Forbidden by inbound security policy */
263 		m_freem(m);
264 		return (EACCES);
265 	}
266 	return (0);
267 }
268 
269 /*
270  * IPsec input callback for INET protocols.
271  * This routine is called as the transform callback.
272  * Takes care of filtering and other sanity checks on
273  * the processed packet.
274  */
275 int
ipsec4_common_input_cb(struct mbuf * m,struct secasvar * sav,int skip,int protoff)276 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip,
277     int protoff)
278 {
279 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
280 	struct epoch_tracker et;
281 	struct ipsec_ctx_data ctx;
282 	struct xform_history *xh;
283 	struct secasindex *saidx;
284 	struct m_tag *mtag;
285 	struct ip *ip;
286 	int error, prot, af, sproto, isr_prot;
287 
288 	IPSEC_ASSERT(sav != NULL, ("null SA"));
289 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
290 	saidx = &sav->sah->saidx;
291 	af = saidx->dst.sa.sa_family;
292 	IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
293 	sproto = saidx->proto;
294 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
295 		sproto == IPPROTO_IPCOMP,
296 		("unexpected security protocol %u", sproto));
297 
298 	if (skip != 0) {
299 		/*
300 		 * Fix IPv4 header
301 		 */
302 		if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
303 			DPRINTF(("%s: processing failed for SA %s/%08lx\n",
304 			    __func__, ipsec_address(&sav->sah->saidx.dst,
305 			    buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
306 			IPSEC_ISTAT(sproto, hdrops);
307 			error = ENOBUFS;
308 			goto bad_noepoch;
309 		}
310 
311 		ip = mtod(m, struct ip *);
312 		ip->ip_len = htons(m->m_pkthdr.len);
313 		ip->ip_sum = 0;
314 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
315 	} else {
316 		ip = mtod(m, struct ip *);
317 	}
318 	prot = ip->ip_p;
319 	/*
320 	 * Check that we have NAT-T enabled and apply transport mode
321 	 * decapsulation NAT procedure (RFC3948).
322 	 * Do this before invoking into the PFIL.
323 	 */
324 	if (sav->natt != NULL &&
325 	    (prot == IPPROTO_UDP || prot == IPPROTO_TCP))
326 		udp_ipsec_adjust_cksum(m, sav, prot, skip);
327 
328 	/*
329 	 * Needed for ipsec_run_hooks and netisr_queue_src
330 	 */
331 	NET_EPOCH_ENTER(et);
332 
333 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, AF_INET, IPSEC_ENC_BEFORE);
334 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
335 		goto bad;
336 	ip = mtod(m, struct ip *);	/* update pointer */
337 
338 	/* IP-in-IP encapsulation */
339 	if (prot == IPPROTO_IPIP &&
340 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
341 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
342 			IPSEC_ISTAT(sproto, hdrops);
343 			error = EINVAL;
344 			goto bad;
345 		}
346 		/* enc0: strip outer IPv4 header */
347 		m_striphdr(m, 0, ip->ip_hl << 2);
348 	}
349 #ifdef INET6
350 	/* IPv6-in-IP encapsulation. */
351 	else if (prot == IPPROTO_IPV6 &&
352 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
353 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
354 			IPSEC_ISTAT(sproto, hdrops);
355 			error = EINVAL;
356 			goto bad;
357 		}
358 		/* enc0: strip IPv4 header, keep IPv6 header only */
359 		m_striphdr(m, 0, ip->ip_hl << 2);
360 	}
361 #endif /* INET6 */
362 	else if (prot != IPPROTO_IPV6 && saidx->mode == IPSEC_MODE_ANY) {
363 		/*
364 		 * When mode is wildcard, inner protocol is IPv6 and
365 		 * we have no INET6 support - drop this packet a bit later.
366 		 * In other cases we assume transport mode. Set prot to
367 		 * correctly choose netisr.
368 		 */
369 		prot = IPPROTO_IPIP;
370 	}
371 
372 	/*
373 	 * Record what we've done to the packet (under what SA it was
374 	 * processed).
375 	 */
376 	if (sproto != IPPROTO_IPCOMP) {
377 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
378 		    sizeof(struct xform_history), M_NOWAIT);
379 		if (mtag == NULL) {
380 			DPRINTF(("%s: failed to get tag\n", __func__));
381 			IPSEC_ISTAT(sproto, hdrops);
382 			error = ENOMEM;
383 			goto bad;
384 		}
385 
386 		xh = (struct xform_history *)(mtag + 1);
387 		bcopy(&saidx->dst, &xh->dst, saidx->dst.sa.sa_len);
388 		xh->spi = sav->spi;
389 		xh->proto = sproto;
390 		xh->mode = saidx->mode;
391 		m_tag_prepend(m, mtag);
392 	}
393 
394 	key_sa_recordxfer(sav, m);		/* record data transfer */
395 
396 	/*
397 	 * In transport mode requeue decrypted mbuf back to IPv4 protocol
398 	 * handler. This is necessary to correctly expose rcvif.
399 	 */
400 	if (saidx->mode == IPSEC_MODE_TRANSPORT)
401 		prot = IPPROTO_IPIP;
402 	/*
403 	 * Re-dispatch via software interrupt.
404 	 */
405 	switch (prot) {
406 	case IPPROTO_IPIP:
407 		isr_prot = NETISR_IP;
408 		af = AF_INET;
409 		break;
410 #ifdef INET6
411 	case IPPROTO_IPV6:
412 		isr_prot = NETISR_IPV6;
413 		af = AF_INET6;
414 		break;
415 #endif
416 	default:
417 		DPRINTF(("%s: cannot handle inner ip proto %d\n",
418 			    __func__, prot));
419 		IPSEC_ISTAT(sproto, nopf);
420 		error = EPFNOSUPPORT;
421 		goto bad;
422 	}
423 
424 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_AFTER);
425 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
426 		goto bad;
427 
428 	/* Handle virtual tunneling interfaces */
429 	if (saidx->mode == IPSEC_MODE_TUNNEL)
430 		error = ipsec_if_input(m, sav, af);
431 	if (error == 0) {
432 		error = netisr_queue_src(isr_prot, (uintptr_t)sav->spi, m);
433 		if (error) {
434 			IPSEC_ISTAT(sproto, qfull);
435 			DPRINTF(("%s: queue full; proto %u packet dropped\n",
436 			    __func__, sproto));
437 		}
438 	}
439 	NET_EPOCH_EXIT(et);
440 	key_freesav(&sav);
441 	return (error);
442 bad:
443 	NET_EPOCH_EXIT(et);
444 bad_noepoch:
445 	key_freesav(&sav);
446 	if (m != NULL)
447 		m_freem(m);
448 	return (error);
449 }
450 #endif /* INET */
451 
452 #ifdef INET6
453 /*
454  * IPSEC_INPUT() method implementation for IPv6.
455  *  0 - Permitted by inbound security policy for further processing.
456  *  EACCES - Forbidden by inbound security policy.
457  *  EINPROGRESS - consumed by IPsec.
458  */
459 int
ipsec6_input(struct mbuf * m,int offset,int proto)460 ipsec6_input(struct mbuf *m, int offset, int proto)
461 {
462 
463 	switch (proto) {
464 	case IPPROTO_AH:
465 	case IPPROTO_ESP:
466 	case IPPROTO_IPCOMP:
467 		/* Do inbound IPsec processing for AH/ESP/IPCOMP */
468 		ipsec_common_input(m, offset,
469 		    offsetof(struct ip6_hdr, ip6_nxt), AF_INET6, proto);
470 		return (EINPROGRESS); /* mbuf consumed by IPsec */
471 	default:
472 		/*
473 		 * Protocols with further headers get their IPsec treatment
474 		 * within the protocol specific processing.
475 		 */
476 		if ((inet6sw[ip6_protox[proto]].pr_flags & PR_LASTHDR) == 0)
477 			return (0);
478 		/* FALLTHROUGH */
479 	};
480 	/*
481 	 * Enforce IPsec policy checking if we are seeing last header.
482 	 */
483 	if (ipsec6_in_reject(m, NULL) != 0) {
484 		/* Forbidden by inbound security policy */
485 		m_freem(m);
486 		return (EACCES);
487 	}
488 	return (0);
489 }
490 
491 /*
492  * IPsec input callback, called by the transform callback. Takes care of
493  * filtering and other sanity checks on the processed packet.
494  */
495 int
ipsec6_common_input_cb(struct mbuf * m,struct secasvar * sav,int skip,int protoff)496 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip,
497     int protoff)
498 {
499 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
500 	struct epoch_tracker et;
501 	struct ipsec_ctx_data ctx;
502 	struct xform_history *xh;
503 	struct secasindex *saidx;
504 	struct ip6_hdr *ip6;
505 	struct m_tag *mtag;
506 	int prot, af, sproto;
507 	int nxt, isr_prot;
508 	int error, nest;
509 	uint8_t nxt8;
510 
511 	IPSEC_ASSERT(sav != NULL, ("null SA"));
512 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
513 	saidx = &sav->sah->saidx;
514 	af = saidx->dst.sa.sa_family;
515 	IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
516 	sproto = saidx->proto;
517 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
518 		sproto == IPPROTO_IPCOMP,
519 		("unexpected security protocol %u", sproto));
520 
521 	NET_EPOCH_ENTER(et);
522 
523 	/* Fix IPv6 header */
524 	if (m->m_len < sizeof(struct ip6_hdr) &&
525 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
526 		DPRINTF(("%s: processing failed for SA %s/%08lx\n",
527 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
528 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
529 
530 		IPSEC_ISTAT(sproto, hdrops);
531 		error = EACCES;
532 		goto bad;
533 	}
534 
535 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_BEFORE);
536 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
537 		goto bad;
538 
539 	ip6 = mtod(m, struct ip6_hdr *);
540 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
541 
542 	/* Save protocol */
543 	m_copydata(m, protoff, 1, &nxt8);
544 	prot = nxt8;
545 
546 	/* IPv6-in-IP encapsulation */
547 	if (prot == IPPROTO_IPV6 &&
548 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
549 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
550 			IPSEC_ISTAT(sproto, hdrops);
551 			error = EINVAL;
552 			goto bad;
553 		}
554 		/* ip6n will now contain the inner IPv6 header. */
555 		m_striphdr(m, 0, skip);
556 		skip = 0;
557 	}
558 #ifdef INET
559 	/* IP-in-IP encapsulation */
560 	else if (prot == IPPROTO_IPIP &&
561 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
562 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
563 			IPSEC_ISTAT(sproto, hdrops);
564 			error = EINVAL;
565 			goto bad;
566 		}
567 		/* ipn will now contain the inner IPv4 header */
568 		m_striphdr(m, 0, skip);
569 		skip = 0;
570 	}
571 #endif /* INET */
572 	else {
573 		prot = IPPROTO_IPV6; /* for correct BPF processing */
574 	}
575 
576 	/*
577 	 * Record what we've done to the packet (under what SA it was
578 	 * processed).
579 	 */
580 	if (sproto != IPPROTO_IPCOMP) {
581 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
582 		    sizeof(struct xform_history), M_NOWAIT);
583 		if (mtag == NULL) {
584 			DPRINTF(("%s: failed to get tag\n", __func__));
585 			IPSEC_ISTAT(sproto, hdrops);
586 			error = ENOMEM;
587 			goto bad;
588 		}
589 
590 		xh = (struct xform_history *)(mtag + 1);
591 		bcopy(&saidx->dst, &xh->dst, saidx->dst.sa.sa_len);
592 		xh->spi = sav->spi;
593 		xh->proto = sproto;
594 		xh->mode = saidx->mode;
595 		m_tag_prepend(m, mtag);
596 	}
597 
598 	key_sa_recordxfer(sav, m);
599 
600 #ifdef INET
601 	if (prot == IPPROTO_IPIP)
602 		af = AF_INET;
603 	else
604 #endif
605 		af = AF_INET6;
606 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_AFTER);
607 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
608 		goto bad;
609 	if (skip == 0) {
610 		/*
611 		 * We stripped outer IPv6 header.
612 		 * Now we should requeue decrypted packet via netisr.
613 		 */
614 		switch (prot) {
615 #ifdef INET
616 		case IPPROTO_IPIP:
617 			isr_prot = NETISR_IP;
618 			break;
619 #endif
620 		case IPPROTO_IPV6:
621 			isr_prot = NETISR_IPV6;
622 			break;
623 		default:
624 			DPRINTF(("%s: cannot handle inner ip proto %d\n",
625 			    __func__, prot));
626 			IPSEC_ISTAT(sproto, nopf);
627 			error = EPFNOSUPPORT;
628 			goto bad;
629 		}
630 		/* Handle virtual tunneling interfaces */
631 		if (saidx->mode == IPSEC_MODE_TUNNEL)
632 			error = ipsec_if_input(m, sav, af);
633 		if (error == 0) {
634 			error = netisr_queue_src(isr_prot,
635 			    (uintptr_t)sav->spi, m);
636 			if (error) {
637 				IPSEC_ISTAT(sproto, qfull);
638 				DPRINTF(("%s: queue full; proto %u packet"
639 				    " dropped\n", __func__, sproto));
640 			}
641 		}
642 		NET_EPOCH_EXIT(et);
643 		key_freesav(&sav);
644 		return (error);
645 	}
646 	/*
647 	 * See the end of ip6_input for this logic.
648 	 * IPPROTO_IPV[46] case will be processed just like other ones
649 	 */
650 	nest = 0;
651 	nxt = nxt8;
652 	while (nxt != IPPROTO_DONE) {
653 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
654 			IP6STAT_INC(ip6s_toomanyhdr);
655 			error = EINVAL;
656 			goto bad;
657 		}
658 
659 		/*
660 		 * Protection against faulty packet - there should be
661 		 * more sanity checks in header chain processing.
662 		 */
663 		if (m->m_pkthdr.len < skip) {
664 			IP6STAT_INC(ip6s_tooshort);
665 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
666 			error = EINVAL;
667 			goto bad;
668 		}
669 		/*
670 		 * Enforce IPsec policy checking if we are seeing last header.
671 		 * note that we do not visit this with protocols with pcb layer
672 		 * code - like udp/tcp/raw ip.
673 		 */
674 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
675 		    ipsec6_in_reject(m, NULL)) {
676 			error = EINVAL;
677 			goto bad;
678 		}
679 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
680 	}
681 	NET_EPOCH_EXIT(et);
682 	key_freesav(&sav);
683 	return (0);
684 bad:
685 	NET_EPOCH_EXIT(et);
686 	key_freesav(&sav);
687 	if (m)
688 		m_freem(m);
689 	return (error);
690 }
691 #endif /* INET6 */
692