xref: /freebsd/sys/netipsec/ipsec_input.c (revision a0d3f1e5bcc62750f8908a2ab807115a0197077a)
1 /*	$FreeBSD$	*/
2 /*	$OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $	*/
3 /*-
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).
7  *
8  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
9  * in November 1995.
10  *
11  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
12  * by Angelos D. Keromytis.
13  *
14  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
15  * and Niels Provos.
16  *
17  * Additional features in 1999 by Angelos D. Keromytis.
18  *
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.
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 "opt_inet.h"
44 #include "opt_inet6.h"
45 #include "opt_ipsec.h"
46 #include "opt_enc.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/domain.h>
53 #include <sys/protosw.h>
54 #include <sys/socket.h>
55 #include <sys/errno.h>
56 #include <sys/syslog.h>
57 
58 #include <net/if.h>
59 #include <net/pfil.h>
60 #include <net/route.h>
61 #include <net/netisr.h>
62 #include <net/vnet.h>
63 
64 #include <netinet/in.h>
65 #include <netinet/in_systm.h>
66 #include <netinet/ip.h>
67 #include <netinet/ip_var.h>
68 #include <netinet/in_var.h>
69 
70 #include <netinet/ip6.h>
71 #ifdef INET6
72 #include <netinet6/ip6_var.h>
73 #endif
74 #include <netinet/in_pcb.h>
75 #ifdef INET6
76 #include <netinet/icmp6.h>
77 #endif
78 
79 #include <netipsec/ipsec.h>
80 #ifdef INET6
81 #include <netipsec/ipsec6.h>
82 #endif
83 #include <netipsec/ah_var.h>
84 #include <netipsec/esp.h>
85 #include <netipsec/esp_var.h>
86 #include <netipsec/ipcomp_var.h>
87 
88 #include <netipsec/key.h>
89 #include <netipsec/keydb.h>
90 
91 #include <netipsec/xform.h>
92 #include <netinet6/ip6protosw.h>
93 
94 #include <machine/in_cksum.h>
95 #include <machine/stdarg.h>
96 
97 #ifdef DEV_ENC
98 #include <net/if_enc.h>
99 #endif
100 
101 
102 #define	IPSEC_ISTAT(proto, name)	do {	\
103 	if ((proto) == IPPROTO_ESP)		\
104 		ESPSTAT_INC(esps_##name);	\
105 	else if ((proto) == IPPROTO_AH)		\
106 		AHSTAT_INC(ahs_##name);		\
107 	else					\
108 		IPCOMPSTAT_INC(ipcomps_##name);	\
109 } while (0)
110 
111 #ifdef INET
112 static void ipsec4_common_ctlinput(int, struct sockaddr *, void *, int);
113 #endif
114 
115 /*
116  * ipsec_common_input gets called when an IPsec-protected packet
117  * is received by IPv4 or IPv6.  Its job is to find the right SA
118  * and call the appropriate transform.  The transform callback
119  * takes care of further processing (like ingress filtering).
120  */
121 static int
122 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
123 {
124 	union sockaddr_union dst_address;
125 	struct secasvar *sav;
126 	u_int32_t spi;
127 	int error;
128 #ifdef INET
129 #ifdef IPSEC_NAT_T
130 	struct m_tag *tag;
131 #endif
132 #endif
133 
134 	IPSEC_ISTAT(sproto, input);
135 
136 	IPSEC_ASSERT(m != NULL, ("null packet"));
137 
138 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
139 		sproto == IPPROTO_IPCOMP,
140 		("unexpected security protocol %u", sproto));
141 
142 	if ((sproto == IPPROTO_ESP && !V_esp_enable) ||
143 	    (sproto == IPPROTO_AH && !V_ah_enable) ||
144 	    (sproto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
145 		m_freem(m);
146 		IPSEC_ISTAT(sproto, pdrops);
147 		return EOPNOTSUPP;
148 	}
149 
150 	if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
151 		m_freem(m);
152 		IPSEC_ISTAT(sproto, hdrops);
153 		DPRINTF(("%s: packet too small\n", __func__));
154 		return EINVAL;
155 	}
156 
157 	/* Retrieve the SPI from the relevant IPsec header */
158 	if (sproto == IPPROTO_ESP)
159 		m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
160 	else if (sproto == IPPROTO_AH)
161 		m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
162 		    (caddr_t) &spi);
163 	else if (sproto == IPPROTO_IPCOMP) {
164 		u_int16_t cpi;
165 		m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
166 		    (caddr_t) &cpi);
167 		spi = ntohl(htons(cpi));
168 	}
169 
170 	/*
171 	 * Find the SA and (indirectly) call the appropriate
172 	 * kernel crypto routine. The resulting mbuf chain is a valid
173 	 * IP packet ready to go through input processing.
174 	 */
175 	bzero(&dst_address, sizeof (dst_address));
176 	dst_address.sa.sa_family = af;
177 	switch (af) {
178 #ifdef INET
179 	case AF_INET:
180 		dst_address.sin.sin_len = sizeof(struct sockaddr_in);
181 		m_copydata(m, offsetof(struct ip, ip_dst),
182 		    sizeof(struct in_addr),
183 		    (caddr_t) &dst_address.sin.sin_addr);
184 #ifdef IPSEC_NAT_T
185 		/* Find the source port for NAT-T; see udp*_espdecap. */
186 		tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL);
187 		if (tag != NULL)
188 			dst_address.sin.sin_port = ((u_int16_t *)(tag + 1))[1];
189 #endif /* IPSEC_NAT_T */
190 		break;
191 #endif /* INET */
192 #ifdef INET6
193 	case AF_INET6:
194 		dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
195 		m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
196 		    sizeof(struct in6_addr),
197 		    (caddr_t) &dst_address.sin6.sin6_addr);
198 		break;
199 #endif /* INET6 */
200 	default:
201 		DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
202 		m_freem(m);
203 		IPSEC_ISTAT(sproto, nopf);
204 		return EPFNOSUPPORT;
205 	}
206 
207 	/* NB: only pass dst since key_allocsa follows RFC2401 */
208 	sav = KEY_ALLOCSA(&dst_address, sproto, spi);
209 	if (sav == NULL) {
210 		DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
211 			  __func__, ipsec_address(&dst_address),
212 			  (u_long) ntohl(spi), sproto));
213 		IPSEC_ISTAT(sproto, notdb);
214 		m_freem(m);
215 		return ENOENT;
216 	}
217 
218 	if (sav->tdb_xform == NULL) {
219 		DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
220 			 __func__, ipsec_address(&dst_address),
221 			 (u_long) ntohl(spi), sproto));
222 		IPSEC_ISTAT(sproto, noxform);
223 		KEY_FREESAV(&sav);
224 		m_freem(m);
225 		return ENXIO;
226 	}
227 
228 	/*
229 	 * Call appropriate transform and return -- callback takes care of
230 	 * everything else.
231 	 */
232 	error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
233 	KEY_FREESAV(&sav);
234 	return error;
235 }
236 
237 #ifdef INET
238 /*
239  * Common input handler for IPv4 AH, ESP, and IPCOMP.
240  */
241 int
242 ipsec4_common_input(struct mbuf *m, ...)
243 {
244 	va_list ap;
245 	int off, nxt;
246 
247 	va_start(ap, m);
248 	off = va_arg(ap, int);
249 	nxt = va_arg(ap, int);
250 	va_end(ap);
251 
252 	return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
253 				  AF_INET, nxt);
254 }
255 
256 void
257 ah4_input(struct mbuf *m, int off)
258 {
259 	ipsec4_common_input(m, off, IPPROTO_AH);
260 }
261 void
262 ah4_ctlinput(int cmd, struct sockaddr *sa, void *v)
263 {
264 	if (sa->sa_family == AF_INET &&
265 	    sa->sa_len == sizeof(struct sockaddr_in))
266 		ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_AH);
267 }
268 
269 void
270 esp4_input(struct mbuf *m, int off)
271 {
272 	ipsec4_common_input(m, off, IPPROTO_ESP);
273 }
274 void
275 esp4_ctlinput(int cmd, struct sockaddr *sa, void *v)
276 {
277 	if (sa->sa_family == AF_INET &&
278 	    sa->sa_len == sizeof(struct sockaddr_in))
279 		ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_ESP);
280 }
281 
282 void
283 ipcomp4_input(struct mbuf *m, int off)
284 {
285 	ipsec4_common_input(m, off, IPPROTO_IPCOMP);
286 }
287 
288 /*
289  * IPsec input callback for INET protocols.
290  * This routine is called as the transform callback.
291  * Takes care of filtering and other sanity checks on
292  * the processed packet.
293  */
294 int
295 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
296 			int skip, int protoff, struct m_tag *mt)
297 {
298 	int prot, af, sproto;
299 	struct ip *ip;
300 	struct m_tag *mtag;
301 	struct tdb_ident *tdbi;
302 	struct secasindex *saidx;
303 	int error;
304 #ifdef INET6
305 #ifdef notyet
306 	char ip6buf[INET6_ADDRSTRLEN];
307 #endif
308 #endif
309 
310 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
311 	IPSEC_ASSERT(sav != NULL, ("null SA"));
312 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
313 	saidx = &sav->sah->saidx;
314 	af = saidx->dst.sa.sa_family;
315 	IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
316 	sproto = saidx->proto;
317 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
318 		sproto == IPPROTO_IPCOMP,
319 		("unexpected security protocol %u", sproto));
320 
321 	/* Sanity check */
322 	if (m == NULL) {
323 		DPRINTF(("%s: null mbuf", __func__));
324 		IPSEC_ISTAT(sproto, badkcr);
325 		KEY_FREESAV(&sav);
326 		return EINVAL;
327 	}
328 
329 	if (skip != 0) {
330 		/*
331 		 * Fix IPv4 header
332 		 * XXXGL: do we need this entire block?
333 		 */
334 		if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
335 			DPRINTF(("%s: processing failed for SA %s/%08lx\n",
336 			    __func__, ipsec_address(&sav->sah->saidx.dst),
337 			    (u_long) ntohl(sav->spi)));
338 			IPSEC_ISTAT(sproto, hdrops);
339 			error = ENOBUFS;
340 			goto bad;
341 		}
342 
343 		ip = mtod(m, struct ip *);
344 		ip->ip_len = htons(m->m_pkthdr.len);
345 		ip->ip_sum = 0;
346 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
347 	} else {
348 		ip = mtod(m, struct ip *);
349 	}
350 	prot = ip->ip_p;
351 
352 #ifdef notyet
353 	/* IP-in-IP encapsulation */
354 	if (prot == IPPROTO_IPIP) {
355 		struct ip ipn;
356 
357 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
358 			IPSEC_ISTAT(sproto, hdrops);
359 			error = EINVAL;
360 			goto bad;
361 		}
362 		/* ipn will now contain the inner IPv4 header */
363 		m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
364 		    (caddr_t) &ipn);
365 
366 		/* XXX PROXY address isn't recorded in SAH */
367 		/*
368 		 * Check that the inner source address is the same as
369 		 * the proxy address, if available.
370 		 */
371 		if ((saidx->proxy.sa.sa_family == AF_INET &&
372 		    saidx->proxy.sin.sin_addr.s_addr !=
373 		    INADDR_ANY &&
374 		    ipn.ip_src.s_addr !=
375 		    saidx->proxy.sin.sin_addr.s_addr) ||
376 		    (saidx->proxy.sa.sa_family != AF_INET &&
377 			saidx->proxy.sa.sa_family != 0)) {
378 
379 			DPRINTF(("%s: inner source address %s doesn't "
380 			    "correspond to expected proxy source %s, "
381 			    "SA %s/%08lx\n", __func__,
382 			    inet_ntoa4(ipn.ip_src),
383 			    ipsp_address(saidx->proxy),
384 			    ipsp_address(saidx->dst),
385 			    (u_long) ntohl(sav->spi)));
386 
387 			IPSEC_ISTAT(sproto, pdrops);
388 			error = EACCES;
389 			goto bad;
390 		}
391 	}
392 #ifdef INET6
393 	/* IPv6-in-IP encapsulation. */
394 	if (prot == IPPROTO_IPV6) {
395 		struct ip6_hdr ip6n;
396 
397 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
398 			IPSEC_ISTAT(sproto, hdrops);
399 			error = EINVAL;
400 			goto bad;
401 		}
402 		/* ip6n will now contain the inner IPv6 header. */
403 		m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
404 		    (caddr_t) &ip6n);
405 
406 		/*
407 		 * Check that the inner source address is the same as
408 		 * the proxy address, if available.
409 		 */
410 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
411 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
412 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
413 			&saidx->proxy.sin6.sin6_addr)) ||
414 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
415 			saidx->proxy.sa.sa_family != 0)) {
416 
417 			DPRINTF(("%s: inner source address %s doesn't "
418 			    "correspond to expected proxy source %s, "
419 			    "SA %s/%08lx\n", __func__,
420 			    ip6_sprintf(ip6buf, &ip6n.ip6_src),
421 			    ipsec_address(&saidx->proxy),
422 			    ipsec_address(&saidx->dst),
423 			    (u_long) ntohl(sav->spi)));
424 
425 			IPSEC_ISTAT(sproto, pdrops);
426 			error = EACCES;
427 			goto bad;
428 		}
429 	}
430 #endif /* INET6 */
431 #endif /*XXX*/
432 
433 	/*
434 	 * Record what we've done to the packet (under what SA it was
435 	 * processed). If we've been passed an mtag, it means the packet
436 	 * was already processed by an ethernet/crypto combo card and
437 	 * thus has a tag attached with all the right information, but
438 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
439 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
440 	 */
441 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
442 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
443 		    sizeof(struct tdb_ident), M_NOWAIT);
444 		if (mtag == NULL) {
445 			DPRINTF(("%s: failed to get tag\n", __func__));
446 			IPSEC_ISTAT(sproto, hdrops);
447 			error = ENOMEM;
448 			goto bad;
449 		}
450 
451 		tdbi = (struct tdb_ident *)(mtag + 1);
452 		bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
453 		tdbi->proto = sproto;
454 		tdbi->spi = sav->spi;
455 		/* Cache those two for enc(4) in xform_ipip. */
456 		tdbi->alg_auth = sav->alg_auth;
457 		tdbi->alg_enc = sav->alg_enc;
458 
459 		m_tag_prepend(m, mtag);
460 	} else if (mt != NULL) {
461 		mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
462 		/* XXX do we need to mark m_flags??? */
463 	}
464 
465 	key_sa_recordxfer(sav, m);		/* record data transfer */
466 
467 #ifdef DEV_ENC
468 	encif->if_ipackets++;
469 	encif->if_ibytes += m->m_pkthdr.len;
470 
471 	/*
472 	 * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
473 	 * packet later after it has been decapsulated.
474 	 */
475 	ipsec_bpf(m, sav, AF_INET, ENC_IN|ENC_BEFORE);
476 
477 	if (prot != IPPROTO_IPIP)
478 		if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_BEFORE)) != 0)
479 			return (error);
480 #endif
481 
482 	/*
483 	 * Re-dispatch via software interrupt.
484 	 */
485 	if ((error = netisr_queue_src(NETISR_IP, (uintptr_t)sav->spi, m))) {
486 		IPSEC_ISTAT(sproto, qfull);
487 		DPRINTF(("%s: queue full; proto %u packet dropped\n",
488 			__func__, sproto));
489 		return error;
490 	}
491 	return 0;
492 bad:
493 	m_freem(m);
494 	return error;
495 }
496 
497 void
498 ipsec4_common_ctlinput(int cmd, struct sockaddr *sa, void *v, int proto)
499 {
500 	/* XXX nothing just yet */
501 }
502 #endif /* INET */
503 
504 #ifdef INET6
505 /* IPv6 AH wrapper. */
506 int
507 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
508 {
509 	int l = 0;
510 	int protoff;
511 	struct ip6_ext ip6e;
512 
513 	if (*offp < sizeof(struct ip6_hdr)) {
514 		DPRINTF(("%s: bad offset %u\n", __func__, *offp));
515 		return IPPROTO_DONE;
516 	} else if (*offp == sizeof(struct ip6_hdr)) {
517 		protoff = offsetof(struct ip6_hdr, ip6_nxt);
518 	} else {
519 		/* Chase down the header chain... */
520 		protoff = sizeof(struct ip6_hdr);
521 
522 		do {
523 			protoff += l;
524 			m_copydata(*mp, protoff, sizeof(ip6e),
525 			    (caddr_t) &ip6e);
526 
527 			if (ip6e.ip6e_nxt == IPPROTO_AH)
528 				l = (ip6e.ip6e_len + 2) << 2;
529 			else
530 				l = (ip6e.ip6e_len + 1) << 3;
531 			IPSEC_ASSERT(l > 0, ("l went zero or negative"));
532 		} while (protoff + l < *offp);
533 
534 		/* Malformed packet check */
535 		if (protoff + l != *offp) {
536 			DPRINTF(("%s: bad packet header chain, protoff %u, "
537 				"l %u, off %u\n", __func__, protoff, l, *offp));
538 			IPSEC_ISTAT(proto, hdrops);
539 			m_freem(*mp);
540 			*mp = NULL;
541 			return IPPROTO_DONE;
542 		}
543 		protoff += offsetof(struct ip6_ext, ip6e_nxt);
544 	}
545 	(void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
546 	return IPPROTO_DONE;
547 }
548 
549 /*
550  * IPsec input callback, called by the transform callback. Takes care of
551  * filtering and other sanity checks on the processed packet.
552  */
553 int
554 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
555     struct m_tag *mt)
556 {
557 	int prot, af, sproto;
558 	struct ip6_hdr *ip6;
559 	struct m_tag *mtag;
560 	struct tdb_ident *tdbi;
561 	struct secasindex *saidx;
562 	int nxt;
563 	u_int8_t nxt8;
564 	int error, nest;
565 #ifdef notyet
566 	char ip6buf[INET6_ADDRSTRLEN];
567 #endif
568 
569 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
570 	IPSEC_ASSERT(sav != NULL, ("null SA"));
571 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
572 	saidx = &sav->sah->saidx;
573 	af = saidx->dst.sa.sa_family;
574 	IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
575 	sproto = saidx->proto;
576 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
577 		sproto == IPPROTO_IPCOMP,
578 		("unexpected security protocol %u", sproto));
579 
580 	/* Sanity check */
581 	if (m == NULL) {
582 		DPRINTF(("%s: null mbuf", __func__));
583 		IPSEC_ISTAT(sproto, badkcr);
584 		error = EINVAL;
585 		goto bad;
586 	}
587 
588 	/* Fix IPv6 header */
589 	if (m->m_len < sizeof(struct ip6_hdr) &&
590 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
591 
592 		DPRINTF(("%s: processing failed for SA %s/%08lx\n",
593 		    __func__, ipsec_address(&sav->sah->saidx.dst),
594 		    (u_long) ntohl(sav->spi)));
595 
596 		IPSEC_ISTAT(sproto, hdrops);
597 		error = EACCES;
598 		goto bad;
599 	}
600 
601 	ip6 = mtod(m, struct ip6_hdr *);
602 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
603 
604 	/* Save protocol */
605 	m_copydata(m, protoff, 1, (unsigned char *) &prot);
606 
607 #ifdef notyet
608 #ifdef INET
609 	/* IP-in-IP encapsulation */
610 	if (prot == IPPROTO_IPIP) {
611 		struct ip ipn;
612 
613 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
614 			IPSEC_ISTAT(sproto, hdrops);
615 			error = EINVAL;
616 			goto bad;
617 		}
618 		/* ipn will now contain the inner IPv4 header */
619 		m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
620 
621 		/*
622 		 * Check that the inner source address is the same as
623 		 * the proxy address, if available.
624 		 */
625 		if ((saidx->proxy.sa.sa_family == AF_INET &&
626 		    saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
627 		    ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
628 		    (saidx->proxy.sa.sa_family != AF_INET &&
629 			saidx->proxy.sa.sa_family != 0)) {
630 
631 			DPRINTF(("%s: inner source address %s doesn't "
632 			    "correspond to expected proxy source %s, "
633 			    "SA %s/%08lx\n", __func__,
634 			    inet_ntoa4(ipn.ip_src),
635 			    ipsec_address(&saidx->proxy),
636 			    ipsec_address(&saidx->dst),
637 			    (u_long) ntohl(sav->spi)));
638 
639 			IPSEC_ISTAT(sproto, pdrops);
640 			error = EACCES;
641 			goto bad;
642 		}
643 	}
644 #endif /* INET */
645 
646 	/* IPv6-in-IP encapsulation */
647 	if (prot == IPPROTO_IPV6) {
648 		struct ip6_hdr ip6n;
649 
650 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
651 			IPSEC_ISTAT(sproto, hdrops);
652 			error = EINVAL;
653 			goto bad;
654 		}
655 		/* ip6n will now contain the inner IPv6 header. */
656 		m_copydata(m, skip, sizeof(struct ip6_hdr),
657 		    (caddr_t) &ip6n);
658 
659 		/*
660 		 * Check that the inner source address is the same as
661 		 * the proxy address, if available.
662 		 */
663 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
664 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
665 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
666 			&saidx->proxy.sin6.sin6_addr)) ||
667 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
668 			saidx->proxy.sa.sa_family != 0)) {
669 
670 			DPRINTF(("%s: inner source address %s doesn't "
671 			    "correspond to expected proxy source %s, "
672 			    "SA %s/%08lx\n", __func__,
673 			    ip6_sprintf(ip6buf, &ip6n.ip6_src),
674 			    ipsec_address(&saidx->proxy),
675 			    ipsec_address(&saidx->dst),
676 			    (u_long) ntohl(sav->spi)));
677 
678 			IPSEC_ISTAT(sproto, pdrops);
679 			error = EACCES;
680 			goto bad;
681 		}
682 	}
683 #endif /*XXX*/
684 
685 	/*
686 	 * Record what we've done to the packet (under what SA it was
687 	 * processed). If we've been passed an mtag, it means the packet
688 	 * was already processed by an ethernet/crypto combo card and
689 	 * thus has a tag attached with all the right information, but
690 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
691 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
692 	 */
693 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
694 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
695 		    sizeof(struct tdb_ident), M_NOWAIT);
696 		if (mtag == NULL) {
697 			DPRINTF(("%s: failed to get tag\n", __func__));
698 			IPSEC_ISTAT(sproto, hdrops);
699 			error = ENOMEM;
700 			goto bad;
701 		}
702 
703 		tdbi = (struct tdb_ident *)(mtag + 1);
704 		bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
705 		tdbi->proto = sproto;
706 		tdbi->spi = sav->spi;
707 		/* Cache those two for enc(4) in xform_ipip. */
708 		tdbi->alg_auth = sav->alg_auth;
709 		tdbi->alg_enc = sav->alg_enc;
710 
711 		m_tag_prepend(m, mtag);
712 	} else {
713 		if (mt != NULL)
714 			mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
715 		/* XXX do we need to mark m_flags??? */
716 	}
717 
718 	key_sa_recordxfer(sav, m);
719 
720 #ifdef DEV_ENC
721 	encif->if_ipackets++;
722 	encif->if_ibytes += m->m_pkthdr.len;
723 
724 	/*
725 	 * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
726 	 * packet later after it has been decapsulated.
727 	 */
728 	ipsec_bpf(m, sav, AF_INET6, ENC_IN|ENC_BEFORE);
729 
730 	/* XXX-BZ does not make sense. */
731 	if (prot != IPPROTO_IPIP)
732 		if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_BEFORE)) != 0)
733 			return (error);
734 #endif
735 
736 	/* Retrieve new protocol */
737 	m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
738 
739 	/*
740 	 * See the end of ip6_input for this logic.
741 	 * IPPROTO_IPV[46] case will be processed just like other ones
742 	 */
743 	nest = 0;
744 	nxt = nxt8;
745 	while (nxt != IPPROTO_DONE) {
746 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
747 			IP6STAT_INC(ip6s_toomanyhdr);
748 			error = EINVAL;
749 			goto bad;
750 		}
751 
752 		/*
753 		 * Protection against faulty packet - there should be
754 		 * more sanity checks in header chain processing.
755 		 */
756 		if (m->m_pkthdr.len < skip) {
757 			IP6STAT_INC(ip6s_tooshort);
758 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
759 			error = EINVAL;
760 			goto bad;
761 		}
762 		/*
763 		 * Enforce IPsec policy checking if we are seeing last header.
764 		 * note that we do not visit this with protocols with pcb layer
765 		 * code - like udp/tcp/raw ip.
766 		 */
767 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
768 		    ipsec6_in_reject(m, NULL)) {
769 			error = EINVAL;
770 			goto bad;
771 		}
772 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
773 	}
774 	return 0;
775 bad:
776 	if (m)
777 		m_freem(m);
778 	return error;
779 }
780 
781 void
782 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
783 {
784 	struct ip6ctlparam *ip6cp = NULL;
785 	struct mbuf *m = NULL;
786 	struct ip6_hdr *ip6;
787 	int off;
788 
789 	if (sa->sa_family != AF_INET6 ||
790 	    sa->sa_len != sizeof(struct sockaddr_in6))
791 		return;
792 	if ((unsigned)cmd >= PRC_NCMDS)
793 		return;
794 
795 	/* if the parameter is from icmp6, decode it. */
796 	if (d != NULL) {
797 		ip6cp = (struct ip6ctlparam *)d;
798 		m = ip6cp->ip6c_m;
799 		ip6 = ip6cp->ip6c_ip6;
800 		off = ip6cp->ip6c_off;
801 	} else {
802 		m = NULL;
803 		ip6 = NULL;
804 		off = 0;	/* calm gcc */
805 	}
806 
807 	if (ip6 != NULL) {
808 
809 		struct ip6ctlparam ip6cp1;
810 
811 		/*
812 		 * Notify the error to all possible sockets via pfctlinput2.
813 		 * Since the upper layer information (such as protocol type,
814 		 * source and destination ports) is embedded in the encrypted
815 		 * data and might have been cut, we can't directly call
816 		 * an upper layer ctlinput function. However, the pcbnotify
817 		 * function will consider source and destination addresses
818 		 * as well as the flow info value, and may be able to find
819 		 * some PCB that should be notified.
820 		 * Although pfctlinput2 will call esp6_ctlinput(), there is
821 		 * no possibility of an infinite loop of function calls,
822 		 * because we don't pass the inner IPv6 header.
823 		 */
824 		bzero(&ip6cp1, sizeof(ip6cp1));
825 		ip6cp1.ip6c_src = ip6cp->ip6c_src;
826 		pfctlinput2(cmd, sa, (void *)&ip6cp1);
827 
828 		/*
829 		 * Then go to special cases that need ESP header information.
830 		 * XXX: We assume that when ip6 is non NULL,
831 		 * M and OFF are valid.
832 		 */
833 
834 		if (cmd == PRC_MSGSIZE) {
835 			struct secasvar *sav;
836 			u_int32_t spi;
837 			int valid;
838 
839 			/* check header length before using m_copydata */
840 			if (m->m_pkthdr.len < off + sizeof (struct esp))
841 				return;
842 			m_copydata(m, off + offsetof(struct esp, esp_spi),
843 				sizeof(u_int32_t), (caddr_t) &spi);
844 			/*
845 			 * Check to see if we have a valid SA corresponding to
846 			 * the address in the ICMP message payload.
847 			 */
848 			sav = KEY_ALLOCSA((union sockaddr_union *)sa,
849 					IPPROTO_ESP, spi);
850 			valid = (sav != NULL);
851 			if (sav)
852 				KEY_FREESAV(&sav);
853 
854 			/* XXX Further validation? */
855 
856 			/*
857 			 * Depending on whether the SA is "valid" and
858 			 * routing table size (mtudisc_{hi,lo}wat), we will:
859 			 * - recalcurate the new MTU and create the
860 			 *   corresponding routing entry, or
861 			 * - ignore the MTU change notification.
862 			 */
863 			icmp6_mtudisc_update(ip6cp, valid);
864 		}
865 	} else {
866 		/* we normally notify any pcb here */
867 	}
868 }
869 #endif /* INET6 */
870