xref: /netbsd-src/sys/netipsec/xform_ah.c (revision b757af438b42b93f8c6571f026d8b8ef3eaf5fc9)
1 /*	$NetBSD: xform_ah.c,v 1.37 2012/01/26 21:10:24 drochner Exp $	*/
2 /*	$FreeBSD: src/sys/netipsec/xform_ah.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $	*/
3 /*	$OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */
4 /*
5  * The authors of this code are John Ioannidis (ji@tla.org),
6  * Angelos D. Keromytis (kermit@csd.uch.gr) and
7  * Niels Provos (provos@physnet.uni-hamburg.de).
8  *
9  * The original version of this code was written by John Ioannidis
10  * for BSD/OS in Athens, Greece, in November 1995.
11  *
12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
13  * by Angelos D. Keromytis.
14  *
15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
16  * and Niels Provos.
17  *
18  * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist.
19  *
20  * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
21  * Angelos D. Keromytis and Niels Provos.
22  * Copyright (c) 1999 Niklas Hallqvist.
23  * Copyright (c) 2001 Angelos D. Keromytis.
24  *
25  * Permission to use, copy, and modify this software with or without fee
26  * is hereby granted, provided that this entire notice is included in
27  * all copies of any software which is or includes a copy or
28  * modification of this software.
29  * You may use this code under the GNU public license if you so wish. Please
30  * contribute changes back to the authors under this freer than GPL license
31  * so that we may further the use of strong encryption without limitations to
32  * all.
33  *
34  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
35  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
36  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
37  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
38  * PURPOSE.
39  */
40 
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: xform_ah.c,v 1.37 2012/01/26 21:10:24 drochner Exp $");
43 
44 #include "opt_inet.h"
45 #ifdef __FreeBSD__
46 #include "opt_inet6.h"
47 #endif
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.h>
54 #include <sys/kernel.h>
55 #include <sys/sysctl.h>
56 #include <sys/socketvar.h> /* for softnet_lock */
57 
58 #include <net/if.h>
59 
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/ip.h>
63 #include <netinet/ip_ecn.h>
64 #include <netinet/ip6.h>
65 
66 #include <net/route.h>
67 #include <netipsec/ipsec.h>
68 #include <netipsec/ipsec_private.h>
69 #include <netipsec/ah.h>
70 #include <netipsec/ah_var.h>
71 #include <netipsec/xform.h>
72 
73 #ifdef INET6
74 #include <netinet6/ip6_var.h>
75 #include <netinet6/scope6_var.h>
76 #include <netipsec/ipsec6.h>
77 #  ifdef __FreeBSD__
78 #  include <netinet6/ip6_ecn.h>
79 #  endif
80 #endif
81 
82 #include <netipsec/key.h>
83 #include <netipsec/key_debug.h>
84 #include <netipsec/ipsec_osdep.h>
85 
86 #include <opencrypto/cryptodev.h>
87 
88 /*
89  * Return header size in bytes.  The old protocol did not support
90  * the replay counter; the new protocol always includes the counter.
91  */
92 #define HDRSIZE(sav) \
93 	(((sav)->flags & SADB_X_EXT_OLD) ? \
94 		sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
95 /*
96  * Return authenticator size in bytes.  The old protocol is known
97  * to use a fixed 16-byte authenticator.  The new algorithm gets
98  * this size from the xform but is (currently) always 12.
99  */
100 #define	AUTHSIZE(sav) \
101 	((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize)
102 
103 percpu_t *ahstat_percpu;
104 
105 int	ah_enable = 1;			/* control flow of packets with AH */
106 int	ip4_ah_cleartos = 1;		/* clear ip_tos when doing AH calc */
107 
108 #ifdef __FreeBSD__
109 SYSCTL_DECL(_net_inet_ah);
110 SYSCTL_INT(_net_inet_ah, OID_AUTO,
111 	ah_enable,	CTLFLAG_RW,	&ah_enable,	0, "");
112 SYSCTL_INT(_net_inet_ah, OID_AUTO,
113 	ah_cleartos,	CTLFLAG_RW,	&ip4_ah_cleartos,	0, "");
114 SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
115 	stats,		CTLFLAG_RD,	&ahstat,	ahstat, "");
116 
117 #endif /* __FreeBSD__ */
118 
119 static unsigned char ipseczeroes[256];	/* larger than an ip6 extension hdr */
120 
121 static int ah_input_cb(struct cryptop*);
122 static int ah_output_cb(struct cryptop*);
123 
124 /*
125  * NB: this is public for use by the PF_KEY support.
126  */
127 const struct auth_hash *
128 ah_algorithm_lookup(int alg)
129 {
130 	if (alg >= AH_ALG_MAX)
131 		return NULL;
132 	switch (alg) {
133 	case SADB_X_AALG_NULL:
134 		return &auth_hash_null;
135 	case SADB_AALG_MD5HMAC:
136 		return &auth_hash_hmac_md5_96;
137 	case SADB_AALG_SHA1HMAC:
138 		return &auth_hash_hmac_sha1_96;
139 	case SADB_X_AALG_RIPEMD160HMAC:
140 		return &auth_hash_hmac_ripemd_160_96;
141 	case SADB_X_AALG_MD5:
142 		return &auth_hash_key_md5;
143 	case SADB_X_AALG_SHA:
144 		return &auth_hash_key_sha1;
145 	case SADB_X_AALG_SHA2_256:
146 		return &auth_hash_hmac_sha2_256;
147 	case SADB_X_AALG_SHA2_384:
148 		return &auth_hash_hmac_sha2_384;
149 	case SADB_X_AALG_SHA2_512:
150 		return &auth_hash_hmac_sha2_512;
151 	case SADB_X_AALG_AES_XCBC_MAC:
152 		return &auth_hash_aes_xcbc_mac_96;
153 	}
154 	return NULL;
155 }
156 
157 size_t
158 ah_hdrsiz(const struct secasvar *sav)
159 {
160 	size_t size;
161 
162 	if (sav != NULL) {
163 		int authsize;
164 		IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
165 			("ah_hdrsiz: null xform"));
166 		/*XXX not right for null algorithm--does it matter??*/
167 		authsize = AUTHSIZE(sav);
168 		size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
169 	} else {
170 		/* default guess */
171 		size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
172 	}
173 	return size;
174 }
175 
176 /*
177  * NB: public for use by esp_init.
178  */
179 int
180 ah_init0(struct secasvar *sav, const struct xformsw *xsp,
181 	 struct cryptoini *cria)
182 {
183 	const struct auth_hash *thash;
184 	int keylen;
185 
186 	thash = ah_algorithm_lookup(sav->alg_auth);
187 	if (thash == NULL) {
188 		DPRINTF(("ah_init: unsupported authentication algorithm %u\n",
189 			sav->alg_auth));
190 		return EINVAL;
191 	}
192 	/*
193 	 * Verify the replay state block allocation is consistent with
194 	 * the protocol type.  We check here so we can make assumptions
195 	 * later during protocol processing.
196 	 */
197 	/* NB: replay state is setup elsewhere (sigh) */
198 	if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
199 		DPRINTF(("ah_init: replay state block inconsistency, "
200 			"%s algorithm %s replay state\n",
201 			(sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
202 			sav->replay == NULL ? "without" : "with"));
203 		return EINVAL;
204 	}
205 	if (sav->key_auth == NULL) {
206 		DPRINTF(("ah_init: no authentication key for %s "
207 			"algorithm\n", thash->name));
208 		return EINVAL;
209 	}
210 	keylen = _KEYLEN(sav->key_auth);
211 	if (keylen != thash->keysize && thash->keysize != 0) {
212 		DPRINTF(("ah_init: invalid keylength %d, algorithm "
213 			 "%s requires keysize %d\n",
214 			 keylen, thash->name, thash->keysize));
215 		return EINVAL;
216 	}
217 
218 	sav->tdb_xform = xsp;
219 	sav->tdb_authalgxform = thash;
220 
221 	/* Initialize crypto session. */
222 	memset(cria, 0, sizeof (*cria));
223 	cria->cri_alg = sav->tdb_authalgxform->type;
224 	cria->cri_klen = _KEYBITS(sav->key_auth);
225 	cria->cri_key = _KEYBUF(sav->key_auth);
226 
227 	return 0;
228 }
229 
230 /*
231  * ah_init() is called when an SPI is being set up.
232  */
233 static int
234 ah_init(struct secasvar *sav, const struct xformsw *xsp)
235 {
236 	struct cryptoini cria;
237 	int error;
238 
239 	error = ah_init0(sav, xsp, &cria);
240 	if (!error)
241 		error = crypto_newsession(&sav->tdb_cryptoid,
242 					   &cria, crypto_support);
243 	return error;
244 }
245 
246 /*
247  * Paranoia.
248  *
249  * NB: public for use by esp_zeroize (XXX).
250  */
251 int
252 ah_zeroize(struct secasvar *sav)
253 {
254 	int err;
255 
256 	if (sav->key_auth)
257 		memset(_KEYBUF(sav->key_auth), 0, _KEYLEN(sav->key_auth));
258 
259 	err = crypto_freesession(sav->tdb_cryptoid);
260 	sav->tdb_cryptoid = 0;
261 	sav->tdb_authalgxform = NULL;
262 	sav->tdb_xform = NULL;
263 	return err;
264 }
265 
266 /*
267  * Massage IPv4/IPv6 headers for AH processing.
268  */
269 static int
270 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
271 {
272 	struct mbuf *m = *m0;
273 	unsigned char *ptr;
274 	int off, count;
275 
276 #ifdef INET
277 	struct ip *ip;
278 #endif /* INET */
279 
280 #ifdef INET6
281 	struct ip6_ext *ip6e;
282 	struct ip6_hdr ip6;
283 	int alloc, ad, nxt;
284 #endif /* INET6 */
285 
286 	switch (proto) {
287 #ifdef INET
288 	case AF_INET:
289 		/*
290 		 * This is the least painful way of dealing with IPv4 header
291 		 * and option processing -- just make sure they're in
292 		 * contiguous memory.
293 		 */
294 		*m0 = m = m_pullup(m, skip);
295 		if (m == NULL) {
296 			DPRINTF(("ah_massage_headers: m_pullup failed\n"));
297 			return ENOBUFS;
298 		}
299 
300 		/* Fix the IP header */
301 		ip = mtod(m, struct ip *);
302 		if (ip4_ah_cleartos)
303 			ip->ip_tos = 0;
304 		ip->ip_ttl = 0;
305 		ip->ip_sum = 0;
306 		ip->ip_off = htons(ntohs(ip->ip_off) & ip4_ah_offsetmask);
307 
308 		/*
309 		 * On FreeBSD, ip_off and ip_len assumed in host endian;
310 		 * they are converted (if necessary) by ip_input().
311 		 * On NetBSD, ip_off and ip_len are in network byte order.
312 		 * They must be massaged back to network byte order
313 		 * before verifying the  HMAC. Moreover, on FreeBSD,
314 		 * we should add `skip' back into the massaged ip_len
315 		 * (presumably ip_input() deducted it before we got here?)
316 		 * whereas on NetBSD, we should not.
317 		 */
318 #ifdef __FreeBSD__
319   #define TOHOST(x) (x)
320 #else
321   #define TOHOST(x) (ntohs(x))
322 #endif
323 		if (!out) {
324 			u_int16_t inlen = TOHOST(ip->ip_len);
325 
326 #ifdef __FreeBSD__
327 			ip->ip_len = htons(inlen + skip);
328 #else  /*!__FreeBSD__ */
329 			ip->ip_len = htons(inlen);
330 #endif /*!__FreeBSD__ */
331 
332 			if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
333 				ip->ip_off  &= IP_OFF_CONVERT(IP_DF);
334 			else
335 				ip->ip_off = 0;
336 		} else {
337 			if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
338 				ip->ip_off &= IP_OFF_CONVERT(IP_DF);
339 			else
340 				ip->ip_off = 0;
341 		}
342 
343 		ptr = mtod(m, unsigned char *);
344 
345 		/* IPv4 option processing */
346 		for (off = sizeof(struct ip); off < skip;) {
347 			if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
348 			    off + 1 < skip)
349 				;
350 			else {
351 				DPRINTF(("ah_massage_headers: illegal IPv4 "
352 				    "option length for option %d\n",
353 				    ptr[off]));
354 
355 				m_freem(m);
356 				return EINVAL;
357 			}
358 
359 			switch (ptr[off]) {
360 			case IPOPT_EOL:
361 				off = skip;  /* End the loop. */
362 				break;
363 
364 			case IPOPT_NOP:
365 				off++;
366 				break;
367 
368 			case IPOPT_SECURITY:	/* 0x82 */
369 			case 0x85:	/* Extended security. */
370 			case 0x86:	/* Commercial security. */
371 			case 0x94:	/* Router alert */
372 			case 0x95:	/* RFC1770 */
373 				/* Sanity check for option length. */
374 				if (ptr[off + 1] < 2) {
375 					DPRINTF(("ah_massage_headers: "
376 					    "illegal IPv4 option length for "
377 					    "option %d\n", ptr[off]));
378 
379 					m_freem(m);
380 					return EINVAL;
381 				}
382 
383 				off += ptr[off + 1];
384 				break;
385 
386 			case IPOPT_LSRR:
387 			case IPOPT_SSRR:
388 				/* Sanity check for option length. */
389 				if (ptr[off + 1] < 2) {
390 					DPRINTF(("ah_massage_headers: "
391 					    "illegal IPv4 option length for "
392 					    "option %d\n", ptr[off]));
393 
394 					m_freem(m);
395 					return EINVAL;
396 				}
397 
398 				/*
399 				 * On output, if we have either of the
400 				 * source routing options, we should
401 				 * swap the destination address of the
402 				 * IP header with the last address
403 				 * specified in the option, as that is
404 				 * what the destination's IP header
405 				 * will look like.
406 				 */
407 				if (out)
408 					bcopy(ptr + off + ptr[off + 1] -
409 					    sizeof(struct in_addr),
410 					    &(ip->ip_dst), sizeof(struct in_addr));
411 
412 				/* Fall through */
413 			default:
414 				/* Sanity check for option length. */
415 				if (ptr[off + 1] < 2) {
416 					DPRINTF(("ah_massage_headers: "
417 					    "illegal IPv4 option length for "
418 					    "option %d\n", ptr[off]));
419 					m_freem(m);
420 					return EINVAL;
421 				}
422 
423 				/* Zeroize all other options. */
424 				count = ptr[off + 1];
425 				memcpy(ptr + off, ipseczeroes, count);
426 				off += count;
427 				break;
428 			}
429 
430 			/* Sanity check. */
431 			if (off > skip)	{
432 				DPRINTF(("ah_massage_headers(): malformed "
433 				    "IPv4 options header\n"));
434 
435 				m_freem(m);
436 				return EINVAL;
437 			}
438 		}
439 
440 		break;
441 #endif /* INET */
442 
443 #ifdef INET6
444 	case AF_INET6:  /* Ugly... */
445 		/* Copy and "cook" the IPv6 header. */
446 		m_copydata(m, 0, sizeof(ip6), &ip6);
447 
448 		/* We don't do IPv6 Jumbograms. */
449 		if (ip6.ip6_plen == 0) {
450 			DPRINTF(("ah_massage_headers: unsupported IPv6 jumbogram\n"));
451 			m_freem(m);
452 			return EMSGSIZE;
453 		}
454 
455 		ip6.ip6_flow = 0;
456 		ip6.ip6_hlim = 0;
457 		ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
458 		ip6.ip6_vfc |= IPV6_VERSION;
459 
460 		/* Scoped address handling. */
461 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
462 			ip6.ip6_src.s6_addr16[1] = 0;
463 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
464 			ip6.ip6_dst.s6_addr16[1] = 0;
465 
466 		/* Done with IPv6 header. */
467 		m_copyback(m, 0, sizeof(struct ip6_hdr), &ip6);
468 
469 		/* Let's deal with the remaining headers (if any). */
470 		if (skip - sizeof(struct ip6_hdr) > 0) {
471 			if (m->m_len <= skip) {
472 				ptr = (unsigned char *) malloc(
473 				    skip - sizeof(struct ip6_hdr),
474 				    M_XDATA, M_NOWAIT);
475 				if (ptr == NULL) {
476 					DPRINTF(("ah_massage_headers: failed "
477 					    "to allocate memory for IPv6 "
478 					    "headers\n"));
479 					m_freem(m);
480 					return ENOBUFS;
481 				}
482 
483 				/*
484 				 * Copy all the protocol headers after
485 				 * the IPv6 header.
486 				 */
487 				m_copydata(m, sizeof(struct ip6_hdr),
488 				    skip - sizeof(struct ip6_hdr), ptr);
489 				alloc = 1;
490 			} else {
491 				/* No need to allocate memory. */
492 				ptr = mtod(m, unsigned char *) +
493 				    sizeof(struct ip6_hdr);
494 				alloc = 0;
495 			}
496 		} else
497 			break;
498 
499 		nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
500 
501 		for (off = 0; off < skip - sizeof(struct ip6_hdr);)
502 			switch (nxt) {
503 			case IPPROTO_HOPOPTS:
504 			case IPPROTO_DSTOPTS:
505 				ip6e = (struct ip6_ext *) (ptr + off);
506 
507 				/*
508 				 * Process the mutable/immutable
509 				 * options -- borrows heavily from the
510 				 * KAME code.
511 				 */
512 				for (count = off + sizeof(struct ip6_ext);
513 				     count < off + ((ip6e->ip6e_len + 1) << 3);) {
514 					if (ptr[count] == IP6OPT_PAD1) {
515 						count++;
516 						continue; /* Skip padding. */
517 					}
518 
519 					/* Sanity check. */
520 					if (count > off +
521 					    ((ip6e->ip6e_len + 1) << 3)) {
522 						m_freem(m);
523 
524 						/* Free, if we allocated. */
525 						if (alloc)
526 							free(ptr, M_XDATA);
527 						return EINVAL;
528 					}
529 
530 					ad = ptr[count + 1];
531 
532 					/* If mutable option, zeroize. */
533 					if (ptr[count] & IP6OPT_MUTABLE)
534 						memcpy(ptr + count, ipseczeroes,
535 						    ptr[count + 1]);
536 
537 					count += ad;
538 
539 					/* Sanity check. */
540 					if (count >
541 					    skip - sizeof(struct ip6_hdr)) {
542 						m_freem(m);
543 
544 						/* Free, if we allocated. */
545 						if (alloc)
546 							free(ptr, M_XDATA);
547 						return EINVAL;
548 					}
549 				}
550 
551 				/* Advance. */
552 				off += ((ip6e->ip6e_len + 1) << 3);
553 				nxt = ip6e->ip6e_nxt;
554 				break;
555 
556 			case IPPROTO_ROUTING:
557 				/*
558 				 * Always include routing headers in
559 				 * computation.
560 				 */
561 				{
562 					struct ip6_rthdr *rh;
563 
564 					ip6e = (struct ip6_ext *) (ptr + off);
565 					rh = (struct ip6_rthdr *)(ptr + off);
566 					/*
567 					 * must adjust content to make it look like
568 					 * its final form (as seen at the final
569 					 * destination).
570 					 * we only know how to massage type 0 routing
571 					 * header.
572 					 */
573 					if (out && rh->ip6r_type == IPV6_RTHDR_TYPE_0) {
574 						struct ip6_rthdr0 *rh0;
575 						struct in6_addr *addr, finaldst;
576 						int i;
577 
578 						rh0 = (struct ip6_rthdr0 *)rh;
579 						addr = (struct in6_addr *)(rh0 + 1);
580 
581 						for (i = 0; i < rh0->ip6r0_segleft; i++)
582 							in6_clearscope(&addr[i]);
583 
584 						finaldst = addr[rh0->ip6r0_segleft - 1];
585 						memmove(&addr[1], &addr[0],
586 							sizeof(struct in6_addr) *
587 							(rh0->ip6r0_segleft - 1));
588 
589 						m_copydata(m, 0, sizeof(ip6), &ip6);
590 						addr[0] = ip6.ip6_dst;
591 						ip6.ip6_dst = finaldst;
592 						m_copyback(m, 0, sizeof(ip6), &ip6);
593 
594 						rh0->ip6r0_segleft = 0;
595 					}
596 
597 					/* advance */
598 					off += ((ip6e->ip6e_len + 1) << 3);
599 					nxt = ip6e->ip6e_nxt;
600 					break;
601 				}
602 
603 			default:
604 				DPRINTF(("ah_massage_headers: unexpected "
605 				    "IPv6 header type %d", off));
606 				if (alloc)
607 					free(ptr, M_XDATA);
608 				m_freem(m);
609 				return EINVAL;
610 			}
611 
612 		/* Copyback and free, if we allocated. */
613 		if (alloc) {
614 			m_copyback(m, sizeof(struct ip6_hdr),
615 			    skip - sizeof(struct ip6_hdr), ptr);
616 			free(ptr, M_XDATA);
617 		}
618 
619 		break;
620 #endif /* INET6 */
621 	}
622 
623 	return 0;
624 }
625 
626 /*
627  * ah_input() gets called to verify that an input packet
628  * passes authentication.
629  */
630 static int
631 ah_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff)
632 {
633 	const struct auth_hash *ahx;
634 	struct tdb_ident *tdbi;
635 	struct tdb_crypto *tc;
636 	struct m_tag *mtag;
637 	struct newah *ah;
638 	int hl, rplen, authsize, error;
639 
640 	struct cryptodesc *crda;
641 	struct cryptop *crp;
642 
643 	IPSEC_SPLASSERT_SOFTNET("ah_input");
644 
645 	IPSEC_ASSERT(sav != NULL, ("ah_input: null SA"));
646 	IPSEC_ASSERT(sav->key_auth != NULL,
647 		("ah_input: null authentication key"));
648 	IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
649 		("ah_input: null authentication xform"));
650 
651 	/* Figure out header size. */
652 	rplen = HDRSIZE(sav);
653 
654 	/* XXX don't pullup, just copy header */
655 	IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
656 	if (ah == NULL) {
657 		DPRINTF(("ah_input: cannot pullup header\n"));
658 		AH_STATINC(AH_STAT_HDROPS);	/*XXX*/
659 		m_freem(m);
660 		return ENOBUFS;
661 	}
662 
663 	/* Check replay window, if applicable. */
664 	if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
665 		AH_STATINC(AH_STAT_REPLAY);
666 		DPRINTF(("ah_input: packet replay failure: %s\n",
667 			  ipsec_logsastr(sav)));
668 		m_freem(m);
669 		return ENOBUFS;
670 	}
671 
672 	/* Verify AH header length. */
673 	hl = ah->ah_len * sizeof (u_int32_t);
674 	ahx = sav->tdb_authalgxform;
675 	authsize = AUTHSIZE(sav);
676 	if (hl != authsize + rplen - sizeof (struct ah)) {
677 		DPRINTF(("ah_input: bad authenticator length %u (expecting %lu)"
678 			" for packet in SA %s/%08lx\n",
679 			hl, (u_long) (authsize + rplen - sizeof (struct ah)),
680 			ipsec_address(&sav->sah->saidx.dst),
681 			(u_long) ntohl(sav->spi)));
682 		AH_STATINC(AH_STAT_BADAUTHL);
683 		m_freem(m);
684 		return EACCES;
685 	}
686 	AH_STATADD(AH_STAT_IBYTES, m->m_pkthdr.len - skip - hl);
687 
688 	/* Get crypto descriptors. */
689 	crp = crypto_getreq(1);
690 	if (crp == NULL) {
691 		DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
692 		AH_STATINC(AH_STAT_CRYPTO);
693 		m_freem(m);
694 		return ENOBUFS;
695 	}
696 
697 	crda = crp->crp_desc;
698 	IPSEC_ASSERT(crda != NULL, ("ah_input: null crypto descriptor"));
699 
700 	crda->crd_skip = 0;
701 	crda->crd_len = m->m_pkthdr.len;
702 	crda->crd_inject = skip + rplen;
703 
704 	/* Authentication operation. */
705 	crda->crd_alg = ahx->type;
706 	crda->crd_key = _KEYBUF(sav->key_auth);
707 	crda->crd_klen = _KEYBITS(sav->key_auth);
708 
709 	/* Find out if we've already done crypto. */
710 	for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
711 	     mtag != NULL;
712 	     mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
713 		tdbi = (struct tdb_ident *) (mtag + 1);
714 		if (tdbi->proto == sav->sah->saidx.proto &&
715 		    tdbi->spi == sav->spi &&
716 		    !memcmp(&tdbi->dst, &sav->sah->saidx.dst,
717 			  sizeof (union sockaddr_union)))
718 			break;
719 	}
720 
721 	/* Allocate IPsec-specific opaque crypto info. */
722 	if (mtag == NULL) {
723 		tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
724 			skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
725 	} else {
726 		/* Hash verification has already been done successfully. */
727 		tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
728 						    M_XDATA, M_NOWAIT|M_ZERO);
729 	}
730 	if (tc == NULL) {
731 		DPRINTF(("ah_input: failed to allocate tdb_crypto\n"));
732 		AH_STATINC(AH_STAT_CRYPTO);
733 		crypto_freereq(crp);
734 		m_freem(m);
735 		return ENOBUFS;
736 	}
737 
738 	error = m_makewritable(&m, 0, skip + rplen + authsize, M_NOWAIT);
739 	if (error) {
740 		m_freem(m);
741 		DPRINTF(("ah_input: failed to copyback_cow\n"));
742 		AH_STATINC(AH_STAT_HDROPS);
743 		free(tc, M_XDATA);
744 		crypto_freereq(crp);
745 		return error;
746 	}
747 
748 	/* Only save information if crypto processing is needed. */
749 	if (mtag == NULL) {
750 		/*
751 		 * Save the authenticator, the skipped portion of the packet,
752 		 * and the AH header.
753 		 */
754 		m_copydata(m, 0, skip + rplen + authsize, (tc + 1));
755 
756 		/* Zeroize the authenticator on the packet. */
757 		m_copyback(m, skip + rplen, authsize, ipseczeroes);
758 
759 		/* "Massage" the packet headers for crypto processing. */
760 		error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
761 		    skip, ahx->type, 0);
762 		if (error != 0) {
763 			/* NB: mbuf is free'd by ah_massage_headers */
764 			AH_STATINC(AH_STAT_HDROPS);
765 			free(tc, M_XDATA);
766 			crypto_freereq(crp);
767 			return error;
768 		}
769 	}
770 
771 	/* Crypto operation descriptor. */
772 	crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
773 	crp->crp_flags = CRYPTO_F_IMBUF;
774 	crp->crp_buf = m;
775 	crp->crp_callback = ah_input_cb;
776 	crp->crp_sid = sav->tdb_cryptoid;
777 	crp->crp_opaque = tc;
778 
779 	/* These are passed as-is to the callback. */
780 	tc->tc_spi = sav->spi;
781 	tc->tc_dst = sav->sah->saidx.dst;
782 	tc->tc_proto = sav->sah->saidx.proto;
783 	tc->tc_nxt = ah->ah_nxt;
784 	tc->tc_protoff = protoff;
785 	tc->tc_skip = skip;
786 	tc->tc_ptr = mtag; /* Save the mtag we've identified. */
787 
788 	DPRINTF(("ah: hash over %d bytes, skip %d: "
789 		 "crda len %d skip %d inject %d\n",
790 		 crp->crp_ilen, tc->tc_skip,
791 		 crda->crd_len, crda->crd_skip, crda->crd_inject));
792 
793 	if (mtag == NULL)
794 		return crypto_dispatch(crp);
795 	else
796 		return ah_input_cb(crp);
797 }
798 
799 #ifdef INET6
800 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {		     \
801 	if (saidx->dst.sa.sa_family == AF_INET6) {			     \
802 		error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
803 	} else {							     \
804 		error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
805 	}								     \
806 } while (0)
807 #else
808 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)		     \
809 	(error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
810 #endif
811 
812 /*
813  * AH input callback from the crypto driver.
814  */
815 static int
816 ah_input_cb(struct cryptop *crp)
817 {
818 	int rplen, error, skip, protoff;
819 	unsigned char calc[AH_ALEN_MAX];
820 	struct mbuf *m;
821 	struct cryptodesc *crd;
822 	const struct auth_hash *ahx;
823 	struct tdb_crypto *tc;
824 	struct m_tag *mtag;
825 	struct secasvar *sav;
826 	struct secasindex *saidx;
827 	u_int8_t nxt;
828 	char *ptr;
829 	int s, authsize;
830 	u_int16_t dport = 0;
831 	u_int16_t sport = 0;
832 #ifdef IPSEC_NAT_T
833 	struct m_tag * tag = NULL;
834 #endif
835 
836 	crd = crp->crp_desc;
837 
838 	tc = (struct tdb_crypto *) crp->crp_opaque;
839 	IPSEC_ASSERT(tc != NULL, ("ah_input_cb: null opaque crypto data area!"));
840 	skip = tc->tc_skip;
841 	nxt = tc->tc_nxt;
842 	protoff = tc->tc_protoff;
843 	mtag = (struct m_tag *) tc->tc_ptr;
844 	m = (struct mbuf *) crp->crp_buf;
845 
846 
847 #ifdef IPSEC_NAT_T
848 	/* find the source port for NAT-T */
849 	if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) {
850 		sport = ((u_int16_t *)(tag + 1))[0];
851 		dport = ((u_int16_t *)(tag + 1))[1];
852 	}
853 #endif
854 
855 	s = splsoftnet();
856 	mutex_enter(softnet_lock);
857 
858 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport);
859 	if (sav == NULL) {
860 		AH_STATINC(AH_STAT_NOTDB);
861 		DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
862 		error = ENOBUFS;		/*XXX*/
863 		goto bad;
864 	}
865 
866 	saidx = &sav->sah->saidx;
867 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
868 		saidx->dst.sa.sa_family == AF_INET6,
869 		("ah_input_cb: unexpected protocol family %u",
870 		 saidx->dst.sa.sa_family));
871 
872 	ahx = sav->tdb_authalgxform;
873 
874 	/* Check for crypto errors. */
875 	if (crp->crp_etype) {
876 		if (sav->tdb_cryptoid != 0)
877 			sav->tdb_cryptoid = crp->crp_sid;
878 
879 		if (crp->crp_etype == EAGAIN) {
880 			mutex_exit(softnet_lock);
881 			splx(s);
882 			return crypto_dispatch(crp);
883 		}
884 
885 		AH_STATINC(AH_STAT_NOXFORM);
886 		DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
887 		error = crp->crp_etype;
888 		goto bad;
889 	} else {
890 		AH_STATINC(AH_STAT_HIST + sav->alg_auth);
891 		crypto_freereq(crp);		/* No longer needed. */
892 		crp = NULL;
893 	}
894 
895 	/* Shouldn't happen... */
896 	if (m == NULL) {
897 		AH_STATINC(AH_STAT_CRYPTO);
898 		DPRINTF(("ah_input_cb: bogus returned buffer from crypto\n"));
899 		error = EINVAL;
900 		goto bad;
901 	}
902 
903 	/* Figure out header size. */
904 	rplen = HDRSIZE(sav);
905 	authsize = AUTHSIZE(sav);
906 
907 	if (ipsec_debug)
908 	  memset(calc, 0, sizeof(calc));
909 
910 	/* Copy authenticator off the packet. */
911 	m_copydata(m, skip + rplen, authsize, calc);
912 
913 	/*
914 	 * If we have an mtag, we don't need to verify the authenticator --
915 	 * it has been verified by an IPsec-aware NIC.
916 	 */
917 	if (mtag == NULL) {
918 		ptr = (char *) (tc + 1);
919 
920 		/* Verify authenticator. */
921 		if (memcmp(ptr + skip + rplen, calc, authsize)) {
922 			u_int8_t *pppp = ptr + skip+rplen;
923 			DPRINTF(("ah_input: authentication hash mismatch " \
924 			    "over %d bytes " \
925 			    "for packet in SA %s/%08lx:\n" \
926 		    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \
927 		    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
928 			    authsize,
929 			    ipsec_address(&saidx->dst),
930 			    (u_long) ntohl(sav->spi),
931 				 calc[0], calc[1], calc[2], calc[3],
932 				 calc[4], calc[5], calc[6], calc[7],
933 				 calc[8], calc[9], calc[10], calc[11],
934 				 pppp[0], pppp[1], pppp[2], pppp[3],
935 				 pppp[4], pppp[5], pppp[6], pppp[7],
936 				 pppp[8], pppp[9], pppp[10], pppp[11]
937 				 ));
938 			AH_STATINC(AH_STAT_BADAUTH);
939 			error = EACCES;
940 			goto bad;
941 		}
942 
943 		/* Fix the Next Protocol field. */
944 		((u_int8_t *) ptr)[protoff] = nxt;
945 
946 		/* Copyback the saved (uncooked) network headers. */
947 		m_copyback(m, 0, skip, ptr);
948 	} else {
949 		/* Fix the Next Protocol field. */
950 		m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
951 	}
952 
953 	free(tc, M_XDATA), tc = NULL;			/* No longer needed */
954 
955 	/*
956 	 * Header is now authenticated.
957 	 */
958 	m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
959 
960 	/*
961 	 * Update replay sequence number, if appropriate.
962 	 */
963 	if (sav->replay) {
964 		u_int32_t seq;
965 
966 		m_copydata(m, skip + offsetof(struct newah, ah_seq),
967 			   sizeof (seq), &seq);
968 		if (ipsec_updatereplay(ntohl(seq), sav)) {
969 			AH_STATINC(AH_STAT_REPLAY);
970 			error = ENOBUFS;			/*XXX as above*/
971 			goto bad;
972 		}
973 	}
974 
975 	/*
976 	 * Remove the AH header and authenticator from the mbuf.
977 	 */
978 	error = m_striphdr(m, skip, rplen + authsize);
979 	if (error) {
980 		DPRINTF(("ah_input_cb: mangled mbuf chain for SA %s/%08lx\n",
981 		    ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
982 
983 		AH_STATINC(AH_STAT_HDROPS);
984 		goto bad;
985 	}
986 
987 	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
988 
989 	KEY_FREESAV(&sav);
990 	mutex_exit(softnet_lock);
991 	splx(s);
992 	return error;
993 bad:
994 	if (sav)
995 		KEY_FREESAV(&sav);
996 	mutex_exit(softnet_lock);
997 	splx(s);
998 	if (m != NULL)
999 		m_freem(m);
1000 	if (tc != NULL)
1001 		free(tc, M_XDATA);
1002 	if (crp != NULL)
1003 		crypto_freereq(crp);
1004 	return error;
1005 }
1006 
1007 /*
1008  * AH output routine, called by ipsec[46]_process_packet().
1009  */
1010 static int
1011 ah_output(
1012     struct mbuf *m,
1013     struct ipsecrequest *isr,
1014     struct mbuf **mp,
1015     int skip,
1016     int protoff
1017 )
1018 {
1019 	const struct secasvar *sav;
1020 	const struct auth_hash *ahx;
1021 	struct cryptodesc *crda;
1022 	struct tdb_crypto *tc;
1023 	struct mbuf *mi;
1024 	struct cryptop *crp;
1025 	u_int16_t iplen;
1026 	int error, rplen, authsize, maxpacketsize, roff;
1027 	u_int8_t prot;
1028 	struct newah *ah;
1029 
1030 	IPSEC_SPLASSERT_SOFTNET("ah_output");
1031 
1032 	sav = isr->sav;
1033 	IPSEC_ASSERT(sav != NULL, ("ah_output: null SA"));
1034 	ahx = sav->tdb_authalgxform;
1035 	IPSEC_ASSERT(ahx != NULL, ("ah_output: null authentication xform"));
1036 
1037 	AH_STATINC(AH_STAT_OUTPUT);
1038 
1039 	/* Figure out header size. */
1040 	rplen = HDRSIZE(sav);
1041 
1042 	/* Check for maximum packet size violations. */
1043 	switch (sav->sah->saidx.dst.sa.sa_family) {
1044 #ifdef INET
1045 	case AF_INET:
1046 		maxpacketsize = IP_MAXPACKET;
1047 		break;
1048 #endif /* INET */
1049 #ifdef INET6
1050 	case AF_INET6:
1051 		maxpacketsize = IPV6_MAXPACKET;
1052 		break;
1053 #endif /* INET6 */
1054 	default:
1055 		DPRINTF(("ah_output: unknown/unsupported protocol "
1056 		    "family %u, SA %s/%08lx\n",
1057 		    sav->sah->saidx.dst.sa.sa_family,
1058 		    ipsec_address(&sav->sah->saidx.dst),
1059 		    (u_long) ntohl(sav->spi)));
1060 		AH_STATINC(AH_STAT_NOPF);
1061 		error = EPFNOSUPPORT;
1062 		goto bad;
1063 	}
1064 	authsize = AUTHSIZE(sav);
1065 	if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
1066 		DPRINTF(("ah_output: packet in SA %s/%08lx got too big "
1067 		    "(len %u, max len %u)\n",
1068 		    ipsec_address(&sav->sah->saidx.dst),
1069 		    (u_long) ntohl(sav->spi),
1070 		    rplen + authsize + m->m_pkthdr.len, maxpacketsize));
1071 		AH_STATINC(AH_STAT_TOOBIG);
1072 		error = EMSGSIZE;
1073 		goto bad;
1074 	}
1075 
1076 	/* Update the counters. */
1077 	AH_STATADD(AH_STAT_OBYTES, m->m_pkthdr.len - skip);
1078 
1079 	m = m_clone(m);
1080 	if (m == NULL) {
1081 		DPRINTF(("ah_output: cannot clone mbuf chain, SA %s/%08lx\n",
1082 		    ipsec_address(&sav->sah->saidx.dst),
1083 		    (u_long) ntohl(sav->spi)));
1084 		AH_STATINC(AH_STAT_HDROPS);
1085 		error = ENOBUFS;
1086 		goto bad;
1087 	}
1088 
1089 	/* Inject AH header. */
1090 	mi = m_makespace(m, skip, rplen + authsize, &roff);
1091 	if (mi == NULL) {
1092 		DPRINTF(("ah_output: failed to inject %u byte AH header for SA "
1093 		    "%s/%08lx\n",
1094 		    rplen + authsize,
1095 		    ipsec_address(&sav->sah->saidx.dst),
1096 		    (u_long) ntohl(sav->spi)));
1097 		AH_STATINC(AH_STAT_HDROPS);	/*XXX differs from openbsd */
1098 		error = ENOBUFS;
1099 		goto bad;
1100 	}
1101 
1102 	/*
1103 	 * The AH header is guaranteed by m_makespace() to be in
1104 	 * contiguous memory, at roff bytes offset into the returned mbuf.
1105 	 */
1106 	ah = (struct newah *)(mtod(mi, char *) + roff);
1107 
1108 	/* Initialize the AH header. */
1109 	m_copydata(m, protoff, sizeof(u_int8_t), &ah->ah_nxt);
1110 	ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
1111 	ah->ah_reserve = 0;
1112 	ah->ah_spi = sav->spi;
1113 
1114 	/* Zeroize authenticator. */
1115 	m_copyback(m, skip + rplen, authsize, ipseczeroes);
1116 
1117 	/* Insert packet replay counter, as requested.  */
1118 	if (sav->replay) {
1119 		if (sav->replay->count == ~0 &&
1120 		    (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
1121 			DPRINTF(("ah_output: replay counter wrapped for SA "
1122 				"%s/%08lx\n",
1123 				ipsec_address(&sav->sah->saidx.dst),
1124 				(u_long) ntohl(sav->spi)));
1125 			AH_STATINC(AH_STAT_WRAP);
1126 			error = EINVAL;
1127 			goto bad;
1128 		}
1129 #ifdef IPSEC_DEBUG
1130 		/* Emulate replay attack when ipsec_replay is TRUE. */
1131 		if (!ipsec_replay)
1132 #endif
1133 			sav->replay->count++;
1134 		ah->ah_seq = htonl(sav->replay->count);
1135 	}
1136 
1137 	/* Get crypto descriptors. */
1138 	crp = crypto_getreq(1);
1139 	if (crp == NULL) {
1140 		DPRINTF(("ah_output: failed to acquire crypto descriptors\n"));
1141 		AH_STATINC(AH_STAT_CRYPTO);
1142 		error = ENOBUFS;
1143 		goto bad;
1144 	}
1145 
1146 	crda = crp->crp_desc;
1147 
1148 	crda->crd_skip = 0;
1149 	crda->crd_inject = skip + rplen;
1150 	crda->crd_len = m->m_pkthdr.len;
1151 
1152 	/* Authentication operation. */
1153 	crda->crd_alg = ahx->type;
1154 	crda->crd_key = _KEYBUF(sav->key_auth);
1155 	crda->crd_klen = _KEYBITS(sav->key_auth);
1156 
1157 	/* Allocate IPsec-specific opaque crypto info. */
1158 	tc = (struct tdb_crypto *) malloc(
1159 		sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1160 	if (tc == NULL) {
1161 		crypto_freereq(crp);
1162 		DPRINTF(("ah_output: failed to allocate tdb_crypto\n"));
1163 		AH_STATINC(AH_STAT_CRYPTO);
1164 		error = ENOBUFS;
1165 		goto bad;
1166 	}
1167 
1168 	/* Save the skipped portion of the packet. */
1169 	m_copydata(m, 0, skip, (tc + 1));
1170 
1171 	/*
1172 	 * Fix IP header length on the header used for
1173 	 * authentication. We don't need to fix the original
1174 	 * header length as it will be fixed by our caller.
1175 	 */
1176 	switch (sav->sah->saidx.dst.sa.sa_family) {
1177 #ifdef INET
1178 	case AF_INET:
1179 		bcopy(((char *)(tc + 1)) +
1180 		    offsetof(struct ip, ip_len),
1181 		    &iplen, sizeof(u_int16_t));
1182 		iplen = htons(ntohs(iplen) + rplen + authsize);
1183 		m_copyback(m, offsetof(struct ip, ip_len),
1184 		    sizeof(u_int16_t), &iplen);
1185 		break;
1186 #endif /* INET */
1187 
1188 #ifdef INET6
1189 	case AF_INET6:
1190 		bcopy(((char *)(tc + 1)) +
1191 		    offsetof(struct ip6_hdr, ip6_plen),
1192 		    &iplen, sizeof(u_int16_t));
1193 		iplen = htons(ntohs(iplen) + rplen + authsize);
1194 		m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1195 		    sizeof(u_int16_t), &iplen);
1196 		break;
1197 #endif /* INET6 */
1198 	}
1199 
1200 	/* Fix the Next Header field in saved header. */
1201 	((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1202 
1203 	/* Update the Next Protocol field in the IP header. */
1204 	prot = IPPROTO_AH;
1205 	m_copyback(m, protoff, sizeof(u_int8_t), &prot);
1206 
1207 	/* "Massage" the packet headers for crypto processing. */
1208 	error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1209 			skip, ahx->type, 1);
1210 	if (error != 0) {
1211 		m = NULL;	/* mbuf was free'd by ah_massage_headers. */
1212 		free(tc, M_XDATA);
1213 		crypto_freereq(crp);
1214 		goto bad;
1215 	}
1216 
1217 	/* Crypto operation descriptor. */
1218 	crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1219 	crp->crp_flags = CRYPTO_F_IMBUF;
1220 	crp->crp_buf = m;
1221 	crp->crp_callback = ah_output_cb;
1222 	crp->crp_sid = sav->tdb_cryptoid;
1223 	crp->crp_opaque = tc;
1224 
1225 	/* These are passed as-is to the callback. */
1226 	tc->tc_isr = isr;
1227 	tc->tc_spi = sav->spi;
1228 	tc->tc_dst = sav->sah->saidx.dst;
1229 	tc->tc_proto = sav->sah->saidx.proto;
1230 	tc->tc_skip = skip;
1231 	tc->tc_protoff = protoff;
1232 
1233 	return crypto_dispatch(crp);
1234 bad:
1235 	if (m)
1236 		m_freem(m);
1237 	return (error);
1238 }
1239 
1240 /*
1241  * AH output callback from the crypto driver.
1242  */
1243 static int
1244 ah_output_cb(struct cryptop *crp)
1245 {
1246 	int skip, protoff, error;
1247 	struct tdb_crypto *tc;
1248 	struct ipsecrequest *isr;
1249 	struct secasvar *sav;
1250 	struct mbuf *m;
1251 	void *ptr;
1252 	int s, err;
1253 
1254 	tc = (struct tdb_crypto *) crp->crp_opaque;
1255 	IPSEC_ASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
1256 	skip = tc->tc_skip;
1257 	protoff = tc->tc_protoff;
1258 	ptr = (tc + 1);
1259 	m = (struct mbuf *) crp->crp_buf;
1260 
1261 	s = splsoftnet();
1262 	mutex_enter(softnet_lock);
1263 
1264 	isr = tc->tc_isr;
1265 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0);
1266 	if (sav == NULL) {
1267 		AH_STATINC(AH_STAT_NOTDB);
1268 		DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
1269 		error = ENOBUFS;		/*XXX*/
1270 		goto bad;
1271 	}
1272 	IPSEC_ASSERT(isr->sav == sav, ("ah_output_cb: SA changed\n"));
1273 
1274 	/* Check for crypto errors. */
1275 	if (crp->crp_etype) {
1276 		if (sav->tdb_cryptoid != 0)
1277 			sav->tdb_cryptoid = crp->crp_sid;
1278 
1279 		if (crp->crp_etype == EAGAIN) {
1280 			KEY_FREESAV(&sav);
1281 			mutex_exit(softnet_lock);
1282 			splx(s);
1283 			return crypto_dispatch(crp);
1284 		}
1285 
1286 		AH_STATINC(AH_STAT_NOXFORM);
1287 		DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
1288 		error = crp->crp_etype;
1289 		goto bad;
1290 	}
1291 
1292 	/* Shouldn't happen... */
1293 	if (m == NULL) {
1294 		AH_STATINC(AH_STAT_CRYPTO);
1295 		DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
1296 		error = EINVAL;
1297 		goto bad;
1298 	}
1299 	AH_STATINC(AH_STAT_HIST + sav->alg_auth);
1300 
1301 	/*
1302 	 * Copy original headers (with the new protocol number) back
1303 	 * in place.
1304 	 */
1305 	m_copyback(m, 0, skip, ptr);
1306 
1307 	/* No longer needed. */
1308 	free(tc, M_XDATA);
1309 	crypto_freereq(crp);
1310 
1311 #ifdef IPSEC_DEBUG
1312 	/* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1313 	if (ipsec_integrity) {
1314 		int alen;
1315 
1316 		/*
1317 		 * Corrupt HMAC if we want to test integrity verification of
1318 		 * the other side.
1319 		 */
1320 		alen = AUTHSIZE(sav);
1321 		m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1322 	}
1323 #endif
1324 
1325 	/* NB: m is reclaimed by ipsec_process_done. */
1326 	err = ipsec_process_done(m, isr);
1327 	KEY_FREESAV(&sav);
1328 	mutex_exit(softnet_lock);
1329 	splx(s);
1330 	return err;
1331 bad:
1332 	if (sav)
1333 		KEY_FREESAV(&sav);
1334 	mutex_exit(softnet_lock);
1335 	splx(s);
1336 	if (m)
1337 		m_freem(m);
1338 	free(tc, M_XDATA);
1339 	crypto_freereq(crp);
1340 	return error;
1341 }
1342 
1343 static struct xformsw ah_xformsw = {
1344 	XF_AH,		XFT_AUTH,	"IPsec AH",
1345 	ah_init,	ah_zeroize,	ah_input,	ah_output,
1346 	NULL,
1347 };
1348 
1349 INITFN void
1350 ah_attach(void)
1351 {
1352 	ahstat_percpu = percpu_alloc(sizeof(uint64_t) * AH_NSTATS);
1353 	xform_register(&ah_xformsw);
1354 }
1355 
1356 #ifdef __FreeBSD__
1357 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
1358 #endif
1359