1 /* $NetBSD: xform_ah.c,v 1.12.2.1 2007/10/31 12:39:29 liamjfoy 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 1.12.2.1 2007/10/31 12:39:29 liamjfoy 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
57 #include <net/if.h>
58
59 #include <netinet/in.h>
60 #include <netinet/in_systm.h>
61 #include <netinet/ip.h>
62 #include <netinet/ip_ecn.h>
63 #include <netinet/ip6.h>
64
65 #include <net/route.h>
66 #include <netipsec/ipsec.h>
67 #include <netipsec/ah.h>
68 #include <netipsec/ah_var.h>
69 #include <netipsec/xform.h>
70
71 #ifdef INET6
72 #include <netinet6/ip6_var.h>
73 #include <netipsec/ipsec6.h>
74 # ifdef __FreeBSD__
75 # include <netinet6/ip6_ecn.h>
76 # endif
77 #endif
78
79 #include <netipsec/key.h>
80 #include <netipsec/key_debug.h>
81 #include <netipsec/ipsec_osdep.h>
82
83 #include <opencrypto/cryptodev.h>
84
85 /*
86 * Return header size in bytes. The old protocol did not support
87 * the replay counter; the new protocol always includes the counter.
88 */
89 #define HDRSIZE(sav) \
90 (((sav)->flags & SADB_X_EXT_OLD) ? \
91 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
92 /*
93 * Return authenticator size in bytes. The old protocol is known
94 * to use a fixed 16-byte authenticator. The new algorithm gets
95 * this size from the xform but is (currently) always 12.
96 */
97 #define AUTHSIZE(sav) \
98 ((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize)
99
100 int ah_enable = 1; /* control flow of packets with AH */
101 int ah_cleartos = 1; /* clear ip_tos when doing AH calc */
102 struct ahstat ahstat;
103
104 #ifdef __FreeBSD__
105 SYSCTL_DECL(_net_inet_ah);
106 SYSCTL_INT(_net_inet_ah, OID_AUTO,
107 ah_enable, CTLFLAG_RW, &ah_enable, 0, "");
108 SYSCTL_INT(_net_inet_ah, OID_AUTO,
109 ah_cleartos, CTLFLAG_RW, &ah_cleartos, 0, "");
110 SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
111 stats, CTLFLAG_RD, &ahstat, ahstat, "");
112
113 #endif /* __FreeBSD__ */
114
115 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
116
117 static int ah_input_cb(struct cryptop*);
118 static int ah_output_cb(struct cryptop*);
119
120 /*
121 * NB: this is public for use by the PF_KEY support.
122 */
123 struct auth_hash *
124 ah_algorithm_lookup(int alg)
125 {
126 if (alg >= AH_ALG_MAX)
127 return NULL;
128 switch (alg) {
129 case SADB_X_AALG_NULL:
130 return &auth_hash_null;
131 case SADB_AALG_MD5HMAC:
132 return &auth_hash_hmac_md5_96;
133 case SADB_AALG_SHA1HMAC:
134 return &auth_hash_hmac_sha1_96;
135 case SADB_X_AALG_RIPEMD160HMAC:
136 return &auth_hash_hmac_ripemd_160_96;
137 case SADB_X_AALG_MD5:
138 return &auth_hash_key_md5;
139 case SADB_X_AALG_SHA:
140 return &auth_hash_key_sha1;
141 case SADB_X_AALG_SHA2_256:
142 return &auth_hash_hmac_sha2_256;
143 case SADB_X_AALG_SHA2_384:
144 return &auth_hash_hmac_sha2_384;
145 case SADB_X_AALG_SHA2_512:
146 return &auth_hash_hmac_sha2_512;
147 }
148 return NULL;
149 }
150
151 size_t
152 ah_hdrsiz(struct secasvar *sav)
153 {
154 size_t size;
155
156 if (sav != NULL) {
157 int authsize;
158 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
159 ("ah_hdrsiz: null xform"));
160 /*XXX not right for null algorithm--does it matter??*/
161 authsize = AUTHSIZE(sav);
162 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
163 } else {
164 /* default guess */
165 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
166 }
167 return size;
168 }
169
170 /*
171 * NB: public for use by esp_init.
172 */
173 int
174 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
175 {
176 struct auth_hash *thash;
177 int keylen;
178
179 thash = ah_algorithm_lookup(sav->alg_auth);
180 if (thash == NULL) {
181 DPRINTF(("ah_init: unsupported authentication algorithm %u\n",
182 sav->alg_auth));
183 return EINVAL;
184 }
185 /*
186 * Verify the replay state block allocation is consistent with
187 * the protocol type. We check here so we can make assumptions
188 * later during protocol processing.
189 */
190 /* NB: replay state is setup elsewhere (sigh) */
191 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
192 DPRINTF(("ah_init: replay state block inconsistency, "
193 "%s algorithm %s replay state\n",
194 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
195 sav->replay == NULL ? "without" : "with"));
196 return EINVAL;
197 }
198 if (sav->key_auth == NULL) {
199 DPRINTF(("ah_init: no authentication key for %s "
200 "algorithm\n", thash->name));
201 return EINVAL;
202 }
203 keylen = _KEYLEN(sav->key_auth);
204 if (keylen != thash->keysize && thash->keysize != 0) {
205 DPRINTF(("ah_init: invalid keylength %d, algorithm "
206 "%s requires keysize %d\n",
207 keylen, thash->name, thash->keysize));
208 return EINVAL;
209 }
210
211 sav->tdb_xform = xsp;
212 sav->tdb_authalgxform = thash;
213
214 /* Initialize crypto session. */
215 bzero(cria, sizeof (*cria));
216 cria->cri_alg = sav->tdb_authalgxform->type;
217 cria->cri_klen = _KEYBITS(sav->key_auth);
218 cria->cri_key = _KEYBUF(sav->key_auth);
219
220 return 0;
221 }
222
223 /*
224 * ah_init() is called when an SPI is being set up.
225 */
226 static int
227 ah_init(struct secasvar *sav, struct xformsw *xsp)
228 {
229 struct cryptoini cria;
230 int error;
231
232 error = ah_init0(sav, xsp, &cria);
233 return error ? error :
234 crypto_newsession(&sav->tdb_cryptoid, &cria, crypto_support);
235 }
236
237 /*
238 * Paranoia.
239 *
240 * NB: public for use by esp_zeroize (XXX).
241 */
242 int
243 ah_zeroize(struct secasvar *sav)
244 {
245 int err;
246
247 if (sav->key_auth)
248 bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
249
250 err = crypto_freesession(sav->tdb_cryptoid);
251 sav->tdb_cryptoid = 0;
252 sav->tdb_authalgxform = NULL;
253 sav->tdb_xform = NULL;
254 return err;
255 }
256
257 /*
258 * Massage IPv4/IPv6 headers for AH processing.
259 */
260 static int
261 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
262 {
263 struct mbuf *m = *m0;
264 unsigned char *ptr;
265 int off, count;
266
267 #ifdef INET
268 struct ip *ip;
269 #endif /* INET */
270
271 #ifdef INET6
272 struct ip6_ext *ip6e;
273 struct ip6_hdr ip6;
274 int alloc, len, ad;
275 #endif /* INET6 */
276
277 switch (proto) {
278 #ifdef INET
279 case AF_INET:
280 /*
281 * This is the least painful way of dealing with IPv4 header
282 * and option processing -- just make sure they're in
283 * contiguous memory.
284 */
285 *m0 = m = m_pullup(m, skip);
286 if (m == NULL) {
287 DPRINTF(("ah_massage_headers: m_pullup failed\n"));
288 return ENOBUFS;
289 }
290
291 /* Fix the IP header */
292 ip = mtod(m, struct ip *);
293 if (ah_cleartos)
294 ip->ip_tos = 0;
295 ip->ip_ttl = 0;
296 ip->ip_sum = 0;
297
298 /*
299 * On FreeBSD, ip_off and ip_len assumed in host endian;
300 * they are converted (if necessary) by ip_input().
301 * On NetBSD, ip_off and ip_len are in network byte order.
302 * They must be massaged back to network byte order
303 * before verifying the HMAC. Moreover, on FreeBSD,
304 * we should add `skip' back into the massaged ip_len
305 * (presumably ip_input() deducted it before we got here?)
306 * whereas on NetBSD, we should not.
307 */
308 #ifdef __FreeBSD__
309 #define TOHOST(x) (x)
310 #else
311 #define TOHOST(x) (ntohs(x))
312 #endif
313 if (!out) {
314 u_int16_t inlen = TOHOST(ip->ip_len);
315
316 #ifdef __FreeBSD__
317 ip->ip_len = htons(inlen + skip);
318 #else /*!__FreeBSD__ */
319 ip->ip_len = htons(inlen);
320 #endif /*!__FreeBSD__ */
321 DPRINTF(("ip len: skip %d, "
322 "in %d host %d: new: raw %d host %d\n",
323 skip,
324 inlen, TOHOST(inlen),
325 ip->ip_len, ntohs(ip->ip_len)));
326
327
328 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
329 ip->ip_off &= IP_OFF_CONVERT(IP_DF);
330 else
331 ip->ip_off = 0;
332 } else {
333 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
334 ip->ip_off &= IP_OFF_CONVERT(IP_DF);
335 else
336 ip->ip_off = 0;
337 }
338
339 ptr = mtod(m, unsigned char *) + sizeof(struct ip);
340
341 /* IPv4 option processing */
342 for (off = sizeof(struct ip); off < skip;) {
343 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
344 off + 1 < skip)
345 ;
346 else {
347 DPRINTF(("ah_massage_headers: illegal IPv4 "
348 "option length for option %d\n",
349 ptr[off]));
350
351 m_freem(m);
352 return EINVAL;
353 }
354
355 switch (ptr[off]) {
356 case IPOPT_EOL:
357 off = skip; /* End the loop. */
358 break;
359
360 case IPOPT_NOP:
361 off++;
362 break;
363
364 case IPOPT_SECURITY: /* 0x82 */
365 case 0x85: /* Extended security. */
366 case 0x86: /* Commercial security. */
367 case 0x94: /* Router alert */
368 case 0x95: /* RFC1770 */
369 /* Sanity check for option length. */
370 if (ptr[off + 1] < 2) {
371 DPRINTF(("ah_massage_headers: "
372 "illegal IPv4 option length for "
373 "option %d\n", ptr[off]));
374
375 m_freem(m);
376 return EINVAL;
377 }
378
379 off += ptr[off + 1];
380 break;
381
382 case IPOPT_LSRR:
383 case IPOPT_SSRR:
384 /* Sanity check for option length. */
385 if (ptr[off + 1] < 2) {
386 DPRINTF(("ah_massage_headers: "
387 "illegal IPv4 option length for "
388 "option %d\n", ptr[off]));
389
390 m_freem(m);
391 return EINVAL;
392 }
393
394 /*
395 * On output, if we have either of the
396 * source routing options, we should
397 * swap the destination address of the
398 * IP header with the last address
399 * specified in the option, as that is
400 * what the destination's IP header
401 * will look like.
402 */
403 if (out)
404 bcopy(ptr + off + ptr[off + 1] -
405 sizeof(struct in_addr),
406 &(ip->ip_dst), sizeof(struct in_addr));
407
408 /* Fall through */
409 default:
410 /* Sanity check for option length. */
411 if (ptr[off + 1] < 2) {
412 DPRINTF(("ah_massage_headers: "
413 "illegal IPv4 option length for "
414 "option %d\n", ptr[off]));
415 m_freem(m);
416 return EINVAL;
417 }
418
419 /* Zeroize all other options. */
420 count = ptr[off + 1];
421 bcopy(ipseczeroes, ptr, count);
422 off += count;
423 break;
424 }
425
426 /* Sanity check. */
427 if (off > skip) {
428 DPRINTF(("ah_massage_headers(): malformed "
429 "IPv4 options header\n"));
430
431 m_freem(m);
432 return EINVAL;
433 }
434 }
435
436 break;
437 #endif /* INET */
438
439 #ifdef INET6
440 case AF_INET6: /* Ugly... */
441 /* Copy and "cook" the IPv6 header. */
442 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
443
444 /* We don't do IPv6 Jumbograms. */
445 if (ip6.ip6_plen == 0) {
446 DPRINTF(("ah_massage_headers: unsupported IPv6 jumbogram\n"));
447 m_freem(m);
448 return EMSGSIZE;
449 }
450
451 ip6.ip6_flow = 0;
452 ip6.ip6_hlim = 0;
453 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
454 ip6.ip6_vfc |= IPV6_VERSION;
455
456 /* Scoped address handling. */
457 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
458 ip6.ip6_src.s6_addr16[1] = 0;
459 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
460 ip6.ip6_dst.s6_addr16[1] = 0;
461
462 /* Done with IPv6 header. */
463 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
464
465 /* Let's deal with the remaining headers (if any). */
466 if (skip - sizeof(struct ip6_hdr) > 0) {
467 if (m->m_len <= skip) {
468 ptr = (unsigned char *) malloc(
469 skip - sizeof(struct ip6_hdr),
470 M_XDATA, M_NOWAIT);
471 if (ptr == NULL) {
472 DPRINTF(("ah_massage_headers: failed "
473 "to allocate memory for IPv6 "
474 "headers\n"));
475 m_freem(m);
476 return ENOBUFS;
477 }
478
479 /*
480 * Copy all the protocol headers after
481 * the IPv6 header.
482 */
483 m_copydata(m, sizeof(struct ip6_hdr),
484 skip - sizeof(struct ip6_hdr), ptr);
485 alloc = 1;
486 } else {
487 /* No need to allocate memory. */
488 ptr = mtod(m, unsigned char *) +
489 sizeof(struct ip6_hdr);
490 alloc = 0;
491 }
492 } else
493 break;
494
495 off = ip6.ip6_nxt & 0xff; /* Next header type. */
496
497 for (len = 0; len < skip - sizeof(struct ip6_hdr);)
498 switch (off) {
499 case IPPROTO_HOPOPTS:
500 case IPPROTO_DSTOPTS:
501 ip6e = (struct ip6_ext *) (ptr + len);
502
503 /*
504 * Process the mutable/immutable
505 * options -- borrows heavily from the
506 * KAME code.
507 */
508 for (count = len + sizeof(struct ip6_ext);
509 count < len + ((ip6e->ip6e_len + 1) << 3);) {
510 if (ptr[count] == IP6OPT_PAD1) {
511 count++;
512 continue; /* Skip padding. */
513 }
514
515 /* Sanity check. */
516 if (count > len +
517 ((ip6e->ip6e_len + 1) << 3)) {
518 m_freem(m);
519
520 /* Free, if we allocated. */
521 if (alloc)
522 FREE(ptr, M_XDATA);
523 return EINVAL;
524 }
525
526 ad = ptr[count + 1];
527
528 /* If mutable option, zeroize. */
529 if (ptr[count] & IP6OPT_MUTABLE)
530 bcopy(ipseczeroes, ptr + count,
531 ptr[count + 1]);
532
533 count += ad;
534
535 /* Sanity check. */
536 if (count >
537 skip - sizeof(struct ip6_hdr)) {
538 m_freem(m);
539
540 /* Free, if we allocated. */
541 if (alloc)
542 FREE(ptr, M_XDATA);
543 return EINVAL;
544 }
545 }
546
547 /* Advance. */
548 len += ((ip6e->ip6e_len + 1) << 3);
549 off = ip6e->ip6e_nxt;
550 break;
551
552 case IPPROTO_ROUTING:
553 /*
554 * Always include routing headers in
555 * computation.
556 */
557 ip6e = (struct ip6_ext *) (ptr + len);
558 len += ((ip6e->ip6e_len + 1) << 3);
559 off = ip6e->ip6e_nxt;
560 break;
561
562 default:
563 DPRINTF(("ah_massage_headers: unexpected "
564 "IPv6 header type %d", off));
565 if (alloc)
566 FREE(ptr, M_XDATA);
567 m_freem(m);
568 return EINVAL;
569 }
570
571 /* Copyback and free, if we allocated. */
572 if (alloc) {
573 m_copyback(m, sizeof(struct ip6_hdr),
574 skip - sizeof(struct ip6_hdr), ptr);
575 free(ptr, M_XDATA);
576 }
577
578 break;
579 #endif /* INET6 */
580 }
581
582 return 0;
583 }
584
585 /*
586 * ah_input() gets called to verify that an input packet
587 * passes authentication.
588 */
589 static int
590 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
591 {
592 struct auth_hash *ahx;
593 struct tdb_ident *tdbi;
594 struct tdb_crypto *tc;
595 struct m_tag *mtag;
596 struct newah *ah;
597 int hl, rplen, authsize;
598
599 struct cryptodesc *crda;
600 struct cryptop *crp;
601
602 IPSEC_SPLASSERT_SOFTNET("ah_input");
603
604 IPSEC_ASSERT(sav != NULL, ("ah_input: null SA"));
605 IPSEC_ASSERT(sav->key_auth != NULL,
606 ("ah_input: null authentication key"));
607 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
608 ("ah_input: null authentication xform"));
609
610 /* Figure out header size. */
611 rplen = HDRSIZE(sav);
612
613 /* XXX don't pullup, just copy header */
614 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
615 if (ah == NULL) {
616 DPRINTF(("ah_input: cannot pullup header\n"));
617 ahstat.ahs_hdrops++; /*XXX*/
618 m_freem(m);
619 return ENOBUFS;
620 }
621
622 /* Check replay window, if applicable. */
623 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
624 ahstat.ahs_replay++;
625 DPRINTF(("ah_input: packet replay failure: %s\n",
626 ipsec_logsastr(sav)));
627 m_freem(m);
628 return ENOBUFS;
629 }
630
631 /* Verify AH header length. */
632 hl = ah->ah_len * sizeof (u_int32_t);
633 ahx = sav->tdb_authalgxform;
634 authsize = AUTHSIZE(sav);
635 if (hl != authsize + rplen - sizeof (struct ah)) {
636 DPRINTF(("ah_input: bad authenticator length %u (expecting %lu)"
637 " for packet in SA %s/%08lx\n",
638 hl, (u_long) (authsize + rplen - sizeof (struct ah)),
639 ipsec_address(&sav->sah->saidx.dst),
640 (u_long) ntohl(sav->spi)));
641 ahstat.ahs_badauthl++;
642 m_freem(m);
643 return EACCES;
644 }
645 ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl;
646 DPRINTF(("ah_input skip %d poff %d\n"
647 "len: hl %d authsize %d rpl %d expect %ld\n",
648 skip, protoff,
649 hl, authsize, rplen,
650 (long)(authsize + rplen - sizeof(struct ah))));
651
652 /* Get crypto descriptors. */
653 crp = crypto_getreq(1);
654 if (crp == NULL) {
655 DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
656 ahstat.ahs_crypto++;
657 m_freem(m);
658 return ENOBUFS;
659 }
660
661 crda = crp->crp_desc;
662 IPSEC_ASSERT(crda != NULL, ("ah_input: null crypto descriptor"));
663
664 crda->crd_skip = 0;
665 crda->crd_len = m->m_pkthdr.len;
666 crda->crd_inject = skip + rplen;
667
668 /* Authentication operation. */
669 crda->crd_alg = ahx->type;
670 crda->crd_key = _KEYBUF(sav->key_auth);
671 crda->crd_klen = _KEYBITS(sav->key_auth);
672
673 /* Find out if we've already done crypto. */
674 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
675 mtag != NULL;
676 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
677 tdbi = (struct tdb_ident *) (mtag + 1);
678 if (tdbi->proto == sav->sah->saidx.proto &&
679 tdbi->spi == sav->spi &&
680 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
681 sizeof (union sockaddr_union)))
682 break;
683 }
684
685 /* Allocate IPsec-specific opaque crypto info. */
686 if (mtag == NULL) {
687 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
688 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
689 } else {
690 /* Hash verification has already been done successfully. */
691 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
692 M_XDATA, M_NOWAIT|M_ZERO);
693 }
694 if (tc == NULL) {
695 DPRINTF(("ah_input: failed to allocate tdb_crypto\n"));
696 ahstat.ahs_crypto++;
697 crypto_freereq(crp);
698 m_freem(m);
699 return ENOBUFS;
700 }
701
702 /* Only save information if crypto processing is needed. */
703 if (mtag == NULL) {
704 int error;
705
706 /*
707 * Save the authenticator, the skipped portion of the packet,
708 * and the AH header.
709 */
710 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
711
712 {
713 u_int8_t *pppp = ((caddr_t)(tc+1))+skip+rplen;
714 DPRINTF(("ah_input: zeroing %d bytes of authent " \
715 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
716 authsize,
717 pppp[0], pppp[1], pppp[2], pppp[3],
718 pppp[4], pppp[5], pppp[6], pppp[7],
719 pppp[8], pppp[9], pppp[10], pppp[11]));
720 }
721
722 /* Zeroize the authenticator on the packet. */
723 m_copyback(m, skip + rplen, authsize, ipseczeroes);
724
725 /* "Massage" the packet headers for crypto processing. */
726 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
727 skip, ahx->type, 0);
728 if (error != 0) {
729 /* NB: mbuf is free'd by ah_massage_headers */
730 ahstat.ahs_hdrops++;
731 free(tc, M_XDATA);
732 crypto_freereq(crp);
733 return error;
734 }
735 }
736
737 /* Crypto operation descriptor. */
738 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
739 crp->crp_flags = CRYPTO_F_IMBUF;
740 crp->crp_buf = (caddr_t) m;
741 crp->crp_callback = ah_input_cb;
742 crp->crp_sid = sav->tdb_cryptoid;
743 crp->crp_opaque = (caddr_t) tc;
744
745 /* These are passed as-is to the callback. */
746 tc->tc_spi = sav->spi;
747 tc->tc_dst = sav->sah->saidx.dst;
748 tc->tc_proto = sav->sah->saidx.proto;
749 tc->tc_nxt = ah->ah_nxt;
750 tc->tc_protoff = protoff;
751 tc->tc_skip = skip;
752 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
753
754 DPRINTF(("ah: hash over %d bytes, skip %d: "
755 "crda len %d skip %d inject %d\n",
756 crp->crp_ilen, tc->tc_skip,
757 crda->crd_len, crda->crd_skip, crda->crd_inject));
758
759 if (mtag == NULL)
760 return crypto_dispatch(crp);
761 else
762 return ah_input_cb(crp);
763 }
764
765 #ifdef INET6
766 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
767 if (saidx->dst.sa.sa_family == AF_INET6) { \
768 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
769 } else { \
770 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
771 } \
772 } while (0)
773 #else
774 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
775 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
776 #endif
777
778 /*
779 * AH input callback from the crypto driver.
780 */
781 static int
782 ah_input_cb(struct cryptop *crp)
783 {
784 int rplen, error, skip, protoff;
785 unsigned char calc[AH_ALEN_MAX];
786 struct mbuf *m;
787 struct cryptodesc *crd;
788 struct auth_hash *ahx;
789 struct tdb_crypto *tc;
790 struct m_tag *mtag;
791 struct secasvar *sav;
792 struct secasindex *saidx;
793 u_int8_t nxt;
794 caddr_t ptr;
795 int s, authsize;
796
797 crd = crp->crp_desc;
798
799 tc = (struct tdb_crypto *) crp->crp_opaque;
800 IPSEC_ASSERT(tc != NULL, ("ah_input_cb: null opaque crypto data area!"));
801 skip = tc->tc_skip;
802 nxt = tc->tc_nxt;
803 protoff = tc->tc_protoff;
804 mtag = (struct m_tag *) tc->tc_ptr;
805 m = (struct mbuf *) crp->crp_buf;
806
807 s = splsoftnet();
808
809 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
810 if (sav == NULL) {
811 ahstat.ahs_notdb++;
812 DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
813 error = ENOBUFS; /*XXX*/
814 goto bad;
815 }
816
817 saidx = &sav->sah->saidx;
818 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
819 saidx->dst.sa.sa_family == AF_INET6,
820 ("ah_input_cb: unexpected protocol family %u",
821 saidx->dst.sa.sa_family));
822
823 ahx = (struct auth_hash *) sav->tdb_authalgxform;
824
825 /* Check for crypto errors. */
826 if (crp->crp_etype) {
827 if (sav->tdb_cryptoid != 0)
828 sav->tdb_cryptoid = crp->crp_sid;
829
830 if (crp->crp_etype == EAGAIN)
831 return crypto_dispatch(crp);
832
833 ahstat.ahs_noxform++;
834 DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
835 error = crp->crp_etype;
836 goto bad;
837 } else {
838 ahstat.ahs_hist[sav->alg_auth]++;
839 crypto_freereq(crp); /* No longer needed. */
840 crp = NULL;
841 }
842
843 /* Shouldn't happen... */
844 if (m == NULL) {
845 ahstat.ahs_crypto++;
846 DPRINTF(("ah_input_cb: bogus returned buffer from crypto\n"));
847 error = EINVAL;
848 goto bad;
849 }
850
851 /* Figure out header size. */
852 rplen = HDRSIZE(sav);
853 authsize = AUTHSIZE(sav);
854
855 if (ipsec_debug)
856 bzero(calc, sizeof(calc));
857
858 /* Copy authenticator off the packet. */
859 m_copydata(m, skip + rplen, authsize, calc);
860
861 /*
862 * If we have an mtag, we don't need to verify the authenticator --
863 * it has been verified by an IPsec-aware NIC.
864 */
865 if (mtag == NULL) {
866 ptr = (caddr_t) (tc + 1);
867
868 /* Verify authenticator. */
869 if (bcmp(ptr + skip + rplen, calc, authsize)) {
870 u_int8_t *pppp = ptr + skip+rplen;
871 DPRINTF(("ah_input: authentication hash mismatch " \
872 "over %d bytes " \
873 "for packet in SA %s/%08lx:\n" \
874 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \
875 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
876 authsize,
877 ipsec_address(&saidx->dst),
878 (u_long) ntohl(sav->spi),
879 calc[0], calc[1], calc[2], calc[3],
880 calc[4], calc[5], calc[6], calc[7],
881 calc[8], calc[9], calc[10], calc[11],
882 pppp[0], pppp[1], pppp[2], pppp[3],
883 pppp[4], pppp[5], pppp[6], pppp[7],
884 pppp[8], pppp[9], pppp[10], pppp[11]
885 ));
886 ahstat.ahs_badauth++;
887 error = EACCES;
888 goto bad;
889 }
890
891 /* Fix the Next Protocol field. */
892 ((u_int8_t *) ptr)[protoff] = nxt;
893
894 /* Copyback the saved (uncooked) network headers. */
895 m_copyback(m, 0, skip, ptr);
896 } else {
897 /* Fix the Next Protocol field. */
898 m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
899 }
900
901 free(tc, M_XDATA), tc = NULL; /* No longer needed */
902
903 /*
904 * Header is now authenticated.
905 */
906 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
907
908 /*
909 * Update replay sequence number, if appropriate.
910 */
911 if (sav->replay) {
912 u_int32_t seq;
913
914 m_copydata(m, skip + offsetof(struct newah, ah_seq),
915 sizeof (seq), (caddr_t) &seq);
916 if (ipsec_updatereplay(ntohl(seq), sav)) {
917 ahstat.ahs_replay++;
918 error = ENOBUFS; /*XXX as above*/
919 goto bad;
920 }
921 }
922
923 /*
924 * Remove the AH header and authenticator from the mbuf.
925 */
926 error = m_striphdr(m, skip, rplen + authsize);
927 if (error) {
928 DPRINTF(("ah_input_cb: mangled mbuf chain for SA %s/%08lx\n",
929 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
930
931 ahstat.ahs_hdrops++;
932 goto bad;
933 }
934
935 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
936
937 KEY_FREESAV(&sav);
938 splx(s);
939 return error;
940 bad:
941 if (sav)
942 KEY_FREESAV(&sav);
943 splx(s);
944 if (m != NULL)
945 m_freem(m);
946 if (tc != NULL)
947 free(tc, M_XDATA);
948 if (crp != NULL)
949 crypto_freereq(crp);
950 return error;
951 }
952
953 /*
954 * AH output routine, called by ipsec[46]_process_packet().
955 */
956 static int
957 ah_output(
958 struct mbuf *m,
959 struct ipsecrequest *isr,
960 struct mbuf **mp,
961 int skip,
962 int protoff
963 )
964 {
965 struct secasvar *sav;
966 struct auth_hash *ahx;
967 struct cryptodesc *crda;
968 struct tdb_crypto *tc;
969 struct mbuf *mi;
970 struct cryptop *crp;
971 u_int16_t iplen;
972 int error, rplen, authsize, maxpacketsize, roff;
973 u_int8_t prot;
974 struct newah *ah;
975
976 IPSEC_SPLASSERT_SOFTNET("ah_output");
977
978 sav = isr->sav;
979 IPSEC_ASSERT(sav != NULL, ("ah_output: null SA"));
980 ahx = sav->tdb_authalgxform;
981 IPSEC_ASSERT(ahx != NULL, ("ah_output: null authentication xform"));
982
983 ahstat.ahs_output++;
984
985 /* Figure out header size. */
986 rplen = HDRSIZE(sav);
987
988 /* Check for maximum packet size violations. */
989 switch (sav->sah->saidx.dst.sa.sa_family) {
990 #ifdef INET
991 case AF_INET:
992 maxpacketsize = IP_MAXPACKET;
993 break;
994 #endif /* INET */
995 #ifdef INET6
996 case AF_INET6:
997 maxpacketsize = IPV6_MAXPACKET;
998 break;
999 #endif /* INET6 */
1000 default:
1001 DPRINTF(("ah_output: unknown/unsupported protocol "
1002 "family %u, SA %s/%08lx\n",
1003 sav->sah->saidx.dst.sa.sa_family,
1004 ipsec_address(&sav->sah->saidx.dst),
1005 (u_long) ntohl(sav->spi)));
1006 ahstat.ahs_nopf++;
1007 error = EPFNOSUPPORT;
1008 goto bad;
1009 }
1010 authsize = AUTHSIZE(sav);
1011 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
1012 DPRINTF(("ah_output: packet in SA %s/%08lx got too big "
1013 "(len %u, max len %u)\n",
1014 ipsec_address(&sav->sah->saidx.dst),
1015 (u_long) ntohl(sav->spi),
1016 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
1017 ahstat.ahs_toobig++;
1018 error = EMSGSIZE;
1019 goto bad;
1020 }
1021
1022 /* Update the counters. */
1023 ahstat.ahs_obytes += m->m_pkthdr.len - skip;
1024
1025 m = m_clone(m);
1026 if (m == NULL) {
1027 DPRINTF(("ah_output: cannot clone mbuf chain, SA %s/%08lx\n",
1028 ipsec_address(&sav->sah->saidx.dst),
1029 (u_long) ntohl(sav->spi)));
1030 ahstat.ahs_hdrops++;
1031 error = ENOBUFS;
1032 goto bad;
1033 }
1034
1035 /* Inject AH header. */
1036 mi = m_makespace(m, skip, rplen + authsize, &roff);
1037 if (mi == NULL) {
1038 DPRINTF(("ah_output: failed to inject %u byte AH header for SA "
1039 "%s/%08lx\n",
1040 rplen + authsize,
1041 ipsec_address(&sav->sah->saidx.dst),
1042 (u_long) ntohl(sav->spi)));
1043 ahstat.ahs_hdrops++; /*XXX differs from openbsd */
1044 error = ENOBUFS;
1045 goto bad;
1046 }
1047
1048 /*
1049 * The AH header is guaranteed by m_makespace() to be in
1050 * contiguous memory, at roff bytes offset into the returned mbuf.
1051 */
1052 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
1053
1054 /* Initialize the AH header. */
1055 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
1056 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
1057 ah->ah_reserve = 0;
1058 ah->ah_spi = sav->spi;
1059
1060 /* Zeroize authenticator. */
1061 m_copyback(m, skip + rplen, authsize, ipseczeroes);
1062
1063 /* Insert packet replay counter, as requested. */
1064 if (sav->replay) {
1065 if (sav->replay->count == ~0 &&
1066 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
1067 DPRINTF(("ah_output: replay counter wrapped for SA "
1068 "%s/%08lx\n",
1069 ipsec_address(&sav->sah->saidx.dst),
1070 (u_long) ntohl(sav->spi)));
1071 ahstat.ahs_wrap++;
1072 error = EINVAL;
1073 goto bad;
1074 }
1075 #ifdef IPSEC_DEBUG
1076 /* Emulate replay attack when ipsec_replay is TRUE. */
1077 if (!ipsec_replay)
1078 #endif
1079 sav->replay->count++;
1080 ah->ah_seq = htonl(sav->replay->count);
1081 }
1082
1083 /* Get crypto descriptors. */
1084 crp = crypto_getreq(1);
1085 if (crp == NULL) {
1086 DPRINTF(("ah_output: failed to acquire crypto descriptors\n"));
1087 ahstat.ahs_crypto++;
1088 error = ENOBUFS;
1089 goto bad;
1090 }
1091
1092 crda = crp->crp_desc;
1093
1094 crda->crd_skip = 0;
1095 crda->crd_inject = skip + rplen;
1096 crda->crd_len = m->m_pkthdr.len;
1097
1098 /* Authentication operation. */
1099 crda->crd_alg = ahx->type;
1100 crda->crd_key = _KEYBUF(sav->key_auth);
1101 crda->crd_klen = _KEYBITS(sav->key_auth);
1102
1103 /* Allocate IPsec-specific opaque crypto info. */
1104 tc = (struct tdb_crypto *) malloc(
1105 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1106 if (tc == NULL) {
1107 crypto_freereq(crp);
1108 DPRINTF(("ah_output: failed to allocate tdb_crypto\n"));
1109 ahstat.ahs_crypto++;
1110 error = ENOBUFS;
1111 goto bad;
1112 }
1113
1114 /* Save the skipped portion of the packet. */
1115 m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1116
1117 /*
1118 * Fix IP header length on the header used for
1119 * authentication. We don't need to fix the original
1120 * header length as it will be fixed by our caller.
1121 */
1122 switch (sav->sah->saidx.dst.sa.sa_family) {
1123 #ifdef INET
1124 case AF_INET:
1125 bcopy(((caddr_t)(tc + 1)) +
1126 offsetof(struct ip, ip_len),
1127 (caddr_t) &iplen, sizeof(u_int16_t));
1128 iplen = htons(ntohs(iplen) + rplen + authsize);
1129 m_copyback(m, offsetof(struct ip, ip_len),
1130 sizeof(u_int16_t), (caddr_t) &iplen);
1131 break;
1132 #endif /* INET */
1133
1134 #ifdef INET6
1135 case AF_INET6:
1136 bcopy(((caddr_t)(tc + 1)) +
1137 offsetof(struct ip6_hdr, ip6_plen),
1138 (caddr_t) &iplen, sizeof(u_int16_t));
1139 iplen = htons(ntohs(iplen) + rplen + authsize);
1140 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1141 sizeof(u_int16_t), (caddr_t) &iplen);
1142 break;
1143 #endif /* INET6 */
1144 }
1145
1146 /* Fix the Next Header field in saved header. */
1147 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1148
1149 /* Update the Next Protocol field in the IP header. */
1150 prot = IPPROTO_AH;
1151 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1152
1153 /* "Massage" the packet headers for crypto processing. */
1154 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1155 skip, ahx->type, 1);
1156 if (error != 0) {
1157 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1158 free(tc, M_XDATA);
1159 crypto_freereq(crp);
1160 goto bad;
1161 }
1162
1163 /* Crypto operation descriptor. */
1164 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1165 crp->crp_flags = CRYPTO_F_IMBUF;
1166 crp->crp_buf = (caddr_t) m;
1167 crp->crp_callback = ah_output_cb;
1168 crp->crp_sid = sav->tdb_cryptoid;
1169 crp->crp_opaque = (caddr_t) tc;
1170
1171 /* These are passed as-is to the callback. */
1172 tc->tc_isr = isr;
1173 tc->tc_spi = sav->spi;
1174 tc->tc_dst = sav->sah->saidx.dst;
1175 tc->tc_proto = sav->sah->saidx.proto;
1176 tc->tc_skip = skip;
1177 tc->tc_protoff = protoff;
1178
1179 return crypto_dispatch(crp);
1180 bad:
1181 if (m)
1182 m_freem(m);
1183 return (error);
1184 }
1185
1186 /*
1187 * AH output callback from the crypto driver.
1188 */
1189 static int
1190 ah_output_cb(struct cryptop *crp)
1191 {
1192 int skip, protoff, error;
1193 struct tdb_crypto *tc;
1194 struct ipsecrequest *isr;
1195 struct secasvar *sav;
1196 struct mbuf *m;
1197 caddr_t ptr;
1198 int s, err;
1199
1200 tc = (struct tdb_crypto *) crp->crp_opaque;
1201 IPSEC_ASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
1202 skip = tc->tc_skip;
1203 protoff = tc->tc_protoff;
1204 ptr = (caddr_t) (tc + 1);
1205 m = (struct mbuf *) crp->crp_buf;
1206
1207 s = splsoftnet();
1208
1209 isr = tc->tc_isr;
1210 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
1211 if (sav == NULL) {
1212 ahstat.ahs_notdb++;
1213 DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
1214 error = ENOBUFS; /*XXX*/
1215 goto bad;
1216 }
1217 IPSEC_ASSERT(isr->sav == sav, ("ah_output_cb: SA changed\n"));
1218
1219 /* Check for crypto errors. */
1220 if (crp->crp_etype) {
1221 if (sav->tdb_cryptoid != 0)
1222 sav->tdb_cryptoid = crp->crp_sid;
1223
1224 if (crp->crp_etype == EAGAIN) {
1225 KEY_FREESAV(&sav);
1226 splx(s);
1227 return crypto_dispatch(crp);
1228 }
1229
1230 ahstat.ahs_noxform++;
1231 DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
1232 error = crp->crp_etype;
1233 goto bad;
1234 }
1235
1236 /* Shouldn't happen... */
1237 if (m == NULL) {
1238 ahstat.ahs_crypto++;
1239 DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
1240 error = EINVAL;
1241 goto bad;
1242 }
1243 ahstat.ahs_hist[sav->alg_auth]++;
1244
1245 /*
1246 * Copy original headers (with the new protocol number) back
1247 * in place.
1248 */
1249 m_copyback(m, 0, skip, ptr);
1250
1251 /* No longer needed. */
1252 free(tc, M_XDATA);
1253 crypto_freereq(crp);
1254
1255 #ifdef IPSEC_DEBUG
1256 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1257 if (ipsec_integrity) {
1258 int alen;
1259
1260 /*
1261 * Corrupt HMAC if we want to test integrity verification of
1262 * the other side.
1263 */
1264 alen = AUTHSIZE(sav);
1265 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1266 }
1267 #endif
1268
1269 /* NB: m is reclaimed by ipsec_process_done. */
1270 err = ipsec_process_done(m, isr);
1271 KEY_FREESAV(&sav);
1272 splx(s);
1273 return err;
1274 bad:
1275 if (sav)
1276 KEY_FREESAV(&sav);
1277 splx(s);
1278 if (m)
1279 m_freem(m);
1280 free(tc, M_XDATA);
1281 crypto_freereq(crp);
1282 return error;
1283 }
1284
1285 static struct xformsw ah_xformsw = {
1286 XF_AH, XFT_AUTH, "IPsec AH",
1287 ah_init, ah_zeroize, ah_input, ah_output,
1288 NULL,
1289 };
1290
1291 INITFN void
1292 ah_attach(void)
1293 {
1294 xform_register(&ah_xformsw);
1295 }
1296
1297 #ifdef __FreeBSD__
1298 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
1299 #endif
Cache object: 9bd33bc0d96b45ae394c9389c445b788
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