1 /* $FreeBSD$ */
2 /* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos 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 * The original version of this code was written by John Ioannidis
9 * for BSD/OS in Athens, Greece, 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 and Niklas Hallqvist.
18 *
19 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
20 * Angelos D. Keromytis and Niels Provos.
21 * Copyright (c) 1999 Niklas Hallqvist.
22 * Copyright (c) 2001 Angelos D. Keromytis.
23 *
24 * Permission to use, copy, and modify this software with or without fee
25 * is hereby granted, provided that this entire notice is included in
26 * all copies of any software which is or includes a copy or
27 * modification of this software.
28 * You may use this code under the GNU public license if you so wish. Please
29 * contribute changes back to the authors under this freer than GPL license
30 * so that we may further the use of strong encryption without limitations to
31 * all.
32 *
33 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
34 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
35 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
36 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
37 * PURPOSE.
38 */
39 #include "opt_inet.h"
40 #include "opt_inet6.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/mbuf.h>
45 #include <sys/socket.h>
46 #include <sys/syslog.h>
47 #include <sys/kernel.h>
48 #include <sys/sysctl.h>
49
50 #include <net/if.h>
51 #include <net/vnet.h>
52
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_ecn.h>
57 #include <netinet/ip6.h>
58
59 #include <net/route.h>
60 #include <netipsec/ipsec.h>
61 #include <netipsec/ah.h>
62 #include <netipsec/ah_var.h>
63 #include <netipsec/xform.h>
64
65 #ifdef INET6
66 #include <netinet6/ip6_var.h>
67 #include <netipsec/ipsec6.h>
68 #include <netinet6/ip6_ecn.h>
69 #endif
70
71 #include <netipsec/key.h>
72 #include <netipsec/key_debug.h>
73
74 #include <opencrypto/cryptodev.h>
75
76 /*
77 * Return header size in bytes. The old protocol did not support
78 * the replay counter; the new protocol always includes the counter.
79 */
80 #define HDRSIZE(sav) \
81 (((sav)->flags & SADB_X_EXT_OLD) ? \
82 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
83 /*
84 * Return authenticator size in bytes. The old protocol is known
85 * to use a fixed 16-byte authenticator. The new algorithm use 12-byte
86 * authenticator.
87 */
88 #define AUTHSIZE(sav) ah_authsize(sav)
89
90 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
91 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
92 VNET_DEFINE(struct ahstat, ahstat);
93
94 SYSCTL_DECL(_net_inet_ah);
95 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO,
96 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
97 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO,
98 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
99 SYSCTL_VNET_STRUCT(_net_inet_ah, IPSECCTL_STATS,
100 stats, CTLFLAG_RD, &VNET_NAME(ahstat), ahstat, "");
101
102 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
103
104 static int ah_input_cb(struct cryptop*);
105 static int ah_output_cb(struct cryptop*);
106
107 static int
108 ah_authsize(struct secasvar *sav)
109 {
110
111 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__));
112
113 if (sav->flags & SADB_X_EXT_OLD)
114 return 16;
115
116 switch (sav->alg_auth) {
117 case SADB_X_AALG_SHA2_256:
118 return 16;
119 case SADB_X_AALG_SHA2_384:
120 return 24;
121 case SADB_X_AALG_SHA2_512:
122 return 32;
123 default:
124 return AH_HMAC_HASHLEN;
125 }
126 /* NOTREACHED */
127 }
128 /*
129 * NB: this is public for use by the PF_KEY support.
130 */
131 struct auth_hash *
132 ah_algorithm_lookup(int alg)
133 {
134 if (alg > SADB_AALG_MAX)
135 return NULL;
136 switch (alg) {
137 case SADB_X_AALG_NULL:
138 return &auth_hash_null;
139 case SADB_AALG_MD5HMAC:
140 return &auth_hash_hmac_md5;
141 case SADB_AALG_SHA1HMAC:
142 return &auth_hash_hmac_sha1;
143 case SADB_X_AALG_RIPEMD160HMAC:
144 return &auth_hash_hmac_ripemd_160;
145 case SADB_X_AALG_MD5:
146 return &auth_hash_key_md5;
147 case SADB_X_AALG_SHA:
148 return &auth_hash_key_sha1;
149 case SADB_X_AALG_SHA2_256:
150 return &auth_hash_hmac_sha2_256;
151 case SADB_X_AALG_SHA2_384:
152 return &auth_hash_hmac_sha2_384;
153 case SADB_X_AALG_SHA2_512:
154 return &auth_hash_hmac_sha2_512;
155 }
156 return NULL;
157 }
158
159 size_t
160 ah_hdrsiz(struct secasvar *sav)
161 {
162 size_t size;
163
164 if (sav != NULL) {
165 int authsize;
166 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
167 /*XXX not right for null algorithm--does it matter??*/
168 authsize = AUTHSIZE(sav);
169 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
170 } else {
171 /* default guess */
172 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
173 }
174 return size;
175 }
176
177 /*
178 * NB: public for use by esp_init.
179 */
180 int
181 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
182 {
183 struct auth_hash *thash;
184 int keylen;
185
186 thash = ah_algorithm_lookup(sav->alg_auth);
187 if (thash == NULL) {
188 DPRINTF(("%s: unsupported authentication algorithm %u\n",
189 __func__, 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(("%s: replay state block inconsistency, "
200 "%s algorithm %s replay state\n", __func__,
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(("%s: no authentication key for %s algorithm\n",
207 __func__, thash->name));
208 return EINVAL;
209 }
210 keylen = _KEYLEN(sav->key_auth);
211 if (keylen != thash->keysize && thash->keysize != 0) {
212 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
213 "keysize %d\n", __func__,
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 bzero(cria, sizeof (*cria));
223 cria->cri_alg = sav->tdb_authalgxform->type;
224 cria->cri_klen = _KEYBITS(sav->key_auth);
225 cria->cri_key = sav->key_auth->key_data;
226 cria->cri_mlen = AUTHSIZE(sav);
227
228 return 0;
229 }
230
231 /*
232 * ah_init() is called when an SPI is being set up.
233 */
234 static int
235 ah_init(struct secasvar *sav, struct xformsw *xsp)
236 {
237 struct cryptoini cria;
238 int error;
239
240 error = ah_init0(sav, xsp, &cria);
241 return error ? error :
242 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
243 }
244
245 /*
246 * Paranoia.
247 *
248 * NB: public for use by esp_zeroize (XXX).
249 */
250 int
251 ah_zeroize(struct secasvar *sav)
252 {
253 int err;
254
255 if (sav->key_auth)
256 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
257
258 err = crypto_freesession(sav->tdb_cryptoid);
259 sav->tdb_cryptoid = 0;
260 sav->tdb_authalgxform = NULL;
261 sav->tdb_xform = NULL;
262 return err;
263 }
264
265 /*
266 * Massage IPv4/IPv6 headers for AH processing.
267 */
268 static int
269 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
270 {
271 struct mbuf *m = *m0;
272 unsigned char *ptr;
273 int off, count;
274
275 #ifdef INET
276 struct ip *ip;
277 #endif /* INET */
278
279 #ifdef INET6
280 struct ip6_ext *ip6e;
281 struct ip6_hdr ip6;
282 int alloc, len, ad;
283 #endif /* INET6 */
284
285 switch (proto) {
286 #ifdef INET
287 case AF_INET:
288 /*
289 * This is the least painful way of dealing with IPv4 header
290 * and option processing -- just make sure they're in
291 * contiguous memory.
292 */
293 *m0 = m = m_pullup(m, skip);
294 if (m == NULL) {
295 DPRINTF(("%s: m_pullup failed\n", __func__));
296 return ENOBUFS;
297 }
298
299 /* Fix the IP header */
300 ip = mtod(m, struct ip *);
301 if (V_ah_cleartos)
302 ip->ip_tos = 0;
303 ip->ip_ttl = 0;
304 ip->ip_sum = 0;
305
306 /*
307 * On input, fix ip_len which has been byte-swapped
308 * at ip_input().
309 */
310 if (!out) {
311 ip->ip_len = htons(ip->ip_len + skip);
312
313 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
314 ip->ip_off = htons(ip->ip_off & IP_DF);
315 else
316 ip->ip_off = 0;
317 } else {
318 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
319 ip->ip_off = htons(ntohs(ip->ip_off) & IP_DF);
320 else
321 ip->ip_off = 0;
322 }
323
324 ptr = mtod(m, unsigned char *) + sizeof(struct ip);
325
326 /* IPv4 option processing */
327 for (off = sizeof(struct ip); off < skip;) {
328 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
329 off + 1 < skip)
330 ;
331 else {
332 DPRINTF(("%s: illegal IPv4 option length for "
333 "option %d\n", __func__, ptr[off]));
334
335 m_freem(m);
336 return EINVAL;
337 }
338
339 switch (ptr[off]) {
340 case IPOPT_EOL:
341 off = skip; /* End the loop. */
342 break;
343
344 case IPOPT_NOP:
345 off++;
346 break;
347
348 case IPOPT_SECURITY: /* 0x82 */
349 case 0x85: /* Extended security. */
350 case 0x86: /* Commercial security. */
351 case 0x94: /* Router alert */
352 case 0x95: /* RFC1770 */
353 /* Sanity check for option length. */
354 if (ptr[off + 1] < 2) {
355 DPRINTF(("%s: illegal IPv4 option "
356 "length for option %d\n",
357 __func__, ptr[off]));
358
359 m_freem(m);
360 return EINVAL;
361 }
362
363 off += ptr[off + 1];
364 break;
365
366 case IPOPT_LSRR:
367 case IPOPT_SSRR:
368 /* Sanity check for option length. */
369 if (ptr[off + 1] < 2) {
370 DPRINTF(("%s: illegal IPv4 option "
371 "length for option %d\n",
372 __func__, ptr[off]));
373
374 m_freem(m);
375 return EINVAL;
376 }
377
378 /*
379 * On output, if we have either of the
380 * source routing options, we should
381 * swap the destination address of the
382 * IP header with the last address
383 * specified in the option, as that is
384 * what the destination's IP header
385 * will look like.
386 */
387 if (out)
388 bcopy(ptr + off + ptr[off + 1] -
389 sizeof(struct in_addr),
390 &(ip->ip_dst), sizeof(struct in_addr));
391
392 /* Fall through */
393 default:
394 /* Sanity check for option length. */
395 if (ptr[off + 1] < 2) {
396 DPRINTF(("%s: illegal IPv4 option "
397 "length for option %d\n",
398 __func__, ptr[off]));
399 m_freem(m);
400 return EINVAL;
401 }
402
403 /* Zeroize all other options. */
404 count = ptr[off + 1];
405 bcopy(ipseczeroes, ptr, count);
406 off += count;
407 break;
408 }
409
410 /* Sanity check. */
411 if (off > skip) {
412 DPRINTF(("%s: malformed IPv4 options header\n",
413 __func__));
414
415 m_freem(m);
416 return EINVAL;
417 }
418 }
419
420 break;
421 #endif /* INET */
422
423 #ifdef INET6
424 case AF_INET6: /* Ugly... */
425 /* Copy and "cook" the IPv6 header. */
426 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
427
428 /* We don't do IPv6 Jumbograms. */
429 if (ip6.ip6_plen == 0) {
430 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
431 m_freem(m);
432 return EMSGSIZE;
433 }
434
435 ip6.ip6_flow = 0;
436 ip6.ip6_hlim = 0;
437 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
438 ip6.ip6_vfc |= IPV6_VERSION;
439
440 /* Scoped address handling. */
441 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
442 ip6.ip6_src.s6_addr16[1] = 0;
443 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
444 ip6.ip6_dst.s6_addr16[1] = 0;
445
446 /* Done with IPv6 header. */
447 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
448
449 /* Let's deal with the remaining headers (if any). */
450 if (skip - sizeof(struct ip6_hdr) > 0) {
451 if (m->m_len <= skip) {
452 ptr = (unsigned char *) malloc(
453 skip - sizeof(struct ip6_hdr),
454 M_XDATA, M_NOWAIT);
455 if (ptr == NULL) {
456 DPRINTF(("%s: failed to allocate memory"
457 "for IPv6 headers\n",__func__));
458 m_freem(m);
459 return ENOBUFS;
460 }
461
462 /*
463 * Copy all the protocol headers after
464 * the IPv6 header.
465 */
466 m_copydata(m, sizeof(struct ip6_hdr),
467 skip - sizeof(struct ip6_hdr), ptr);
468 alloc = 1;
469 } else {
470 /* No need to allocate memory. */
471 ptr = mtod(m, unsigned char *) +
472 sizeof(struct ip6_hdr);
473 alloc = 0;
474 }
475 } else
476 break;
477
478 off = ip6.ip6_nxt & 0xff; /* Next header type. */
479
480 for (len = 0; len < skip - sizeof(struct ip6_hdr);)
481 switch (off) {
482 case IPPROTO_HOPOPTS:
483 case IPPROTO_DSTOPTS:
484 ip6e = (struct ip6_ext *) (ptr + len);
485
486 /*
487 * Process the mutable/immutable
488 * options -- borrows heavily from the
489 * KAME code.
490 */
491 for (count = len + sizeof(struct ip6_ext);
492 count < len + ((ip6e->ip6e_len + 1) << 3);) {
493 if (ptr[count] == IP6OPT_PAD1) {
494 count++;
495 continue; /* Skip padding. */
496 }
497
498 /* Sanity check. */
499 if (count > len +
500 ((ip6e->ip6e_len + 1) << 3)) {
501 m_freem(m);
502
503 /* Free, if we allocated. */
504 if (alloc)
505 free(ptr, M_XDATA);
506 return EINVAL;
507 }
508
509 ad = ptr[count + 1];
510
511 /* If mutable option, zeroize. */
512 if (ptr[count] & IP6OPT_MUTABLE)
513 bcopy(ipseczeroes, ptr + count,
514 ptr[count + 1]);
515
516 count += ad;
517
518 /* Sanity check. */
519 if (count >
520 skip - sizeof(struct ip6_hdr)) {
521 m_freem(m);
522
523 /* Free, if we allocated. */
524 if (alloc)
525 free(ptr, M_XDATA);
526 return EINVAL;
527 }
528 }
529
530 /* Advance. */
531 len += ((ip6e->ip6e_len + 1) << 3);
532 off = ip6e->ip6e_nxt;
533 break;
534
535 case IPPROTO_ROUTING:
536 /*
537 * Always include routing headers in
538 * computation.
539 */
540 ip6e = (struct ip6_ext *) (ptr + len);
541 len += ((ip6e->ip6e_len + 1) << 3);
542 off = ip6e->ip6e_nxt;
543 break;
544
545 default:
546 DPRINTF(("%s: unexpected IPv6 header type %d",
547 __func__, off));
548 if (alloc)
549 free(ptr, M_XDATA);
550 m_freem(m);
551 return EINVAL;
552 }
553
554 /* Copyback and free, if we allocated. */
555 if (alloc) {
556 m_copyback(m, sizeof(struct ip6_hdr),
557 skip - sizeof(struct ip6_hdr), ptr);
558 free(ptr, M_XDATA);
559 }
560
561 break;
562 #endif /* INET6 */
563 }
564
565 return 0;
566 }
567
568 /*
569 * ah_input() gets called to verify that an input packet
570 * passes authentication.
571 */
572 static int
573 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
574 {
575 struct auth_hash *ahx;
576 struct tdb_ident *tdbi;
577 struct tdb_crypto *tc;
578 struct m_tag *mtag;
579 struct newah *ah;
580 int hl, rplen, authsize;
581
582 struct cryptodesc *crda;
583 struct cryptop *crp;
584
585 IPSEC_ASSERT(sav != NULL, ("null SA"));
586 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
587 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
588 ("null authentication xform"));
589
590 /* Figure out header size. */
591 rplen = HDRSIZE(sav);
592
593 /* XXX don't pullup, just copy header */
594 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
595 if (ah == NULL) {
596 DPRINTF(("ah_input: cannot pullup header\n"));
597 V_ahstat.ahs_hdrops++; /*XXX*/
598 m_freem(m);
599 return ENOBUFS;
600 }
601
602 /* Check replay window, if applicable. */
603 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
604 V_ahstat.ahs_replay++;
605 DPRINTF(("%s: packet replay failure: %s\n", __func__,
606 ipsec_logsastr(sav)));
607 m_freem(m);
608 return ENOBUFS;
609 }
610
611 /* Verify AH header length. */
612 hl = ah->ah_len * sizeof (u_int32_t);
613 ahx = sav->tdb_authalgxform;
614 authsize = AUTHSIZE(sav);
615 if (hl != authsize + rplen - sizeof (struct ah)) {
616 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
617 " for packet in SA %s/%08lx\n", __func__,
618 hl, (u_long) (authsize + rplen - sizeof (struct ah)),
619 ipsec_address(&sav->sah->saidx.dst),
620 (u_long) ntohl(sav->spi)));
621 V_ahstat.ahs_badauthl++;
622 m_freem(m);
623 return EACCES;
624 }
625 V_ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl;
626
627 /* Get crypto descriptors. */
628 crp = crypto_getreq(1);
629 if (crp == NULL) {
630 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
631 V_ahstat.ahs_crypto++;
632 m_freem(m);
633 return ENOBUFS;
634 }
635
636 crda = crp->crp_desc;
637 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
638
639 crda->crd_skip = 0;
640 crda->crd_len = m->m_pkthdr.len;
641 crda->crd_inject = skip + rplen;
642
643 /* Authentication operation. */
644 crda->crd_alg = ahx->type;
645 crda->crd_klen = _KEYBITS(sav->key_auth);
646 crda->crd_key = sav->key_auth->key_data;
647
648 /* Find out if we've already done crypto. */
649 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
650 mtag != NULL;
651 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
652 tdbi = (struct tdb_ident *) (mtag + 1);
653 if (tdbi->proto == sav->sah->saidx.proto &&
654 tdbi->spi == sav->spi &&
655 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
656 sizeof (union sockaddr_union)))
657 break;
658 }
659
660 /* Allocate IPsec-specific opaque crypto info. */
661 if (mtag == NULL) {
662 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
663 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
664 } else {
665 /* Hash verification has already been done successfully. */
666 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
667 M_XDATA, M_NOWAIT|M_ZERO);
668 }
669 if (tc == NULL) {
670 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
671 V_ahstat.ahs_crypto++;
672 crypto_freereq(crp);
673 m_freem(m);
674 return ENOBUFS;
675 }
676
677 /* Only save information if crypto processing is needed. */
678 if (mtag == NULL) {
679 int error;
680
681 /*
682 * Save the authenticator, the skipped portion of the packet,
683 * and the AH header.
684 */
685 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
686
687 /* Zeroize the authenticator on the packet. */
688 m_copyback(m, skip + rplen, authsize, ipseczeroes);
689
690 /* "Massage" the packet headers for crypto processing. */
691 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
692 skip, ahx->type, 0);
693 if (error != 0) {
694 /* NB: mbuf is free'd by ah_massage_headers */
695 V_ahstat.ahs_hdrops++;
696 free(tc, M_XDATA);
697 crypto_freereq(crp);
698 return error;
699 }
700 }
701
702 /* Crypto operation descriptor. */
703 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
704 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
705 crp->crp_buf = (caddr_t) m;
706 crp->crp_callback = ah_input_cb;
707 crp->crp_sid = sav->tdb_cryptoid;
708 crp->crp_opaque = (caddr_t) tc;
709
710 /* These are passed as-is to the callback. */
711 tc->tc_spi = sav->spi;
712 tc->tc_dst = sav->sah->saidx.dst;
713 tc->tc_proto = sav->sah->saidx.proto;
714 tc->tc_nxt = ah->ah_nxt;
715 tc->tc_protoff = protoff;
716 tc->tc_skip = skip;
717 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
718 KEY_ADDREFSA(sav);
719 tc->tc_sav = sav;
720
721 if (mtag == NULL)
722 return crypto_dispatch(crp);
723 else
724 return ah_input_cb(crp);
725 }
726
727 #ifdef INET6
728 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
729 if (saidx->dst.sa.sa_family == AF_INET6) { \
730 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
731 } else { \
732 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
733 } \
734 } while (0)
735 #else
736 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
737 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
738 #endif
739
740 /*
741 * AH input callback from the crypto driver.
742 */
743 static int
744 ah_input_cb(struct cryptop *crp)
745 {
746 int rplen, error, skip, protoff;
747 unsigned char calc[AH_ALEN_MAX];
748 struct mbuf *m;
749 struct cryptodesc *crd;
750 struct auth_hash *ahx;
751 struct tdb_crypto *tc;
752 struct m_tag *mtag;
753 struct secasvar *sav;
754 struct secasindex *saidx;
755 u_int8_t nxt;
756 caddr_t ptr;
757 int authsize;
758
759 crd = crp->crp_desc;
760
761 tc = (struct tdb_crypto *) crp->crp_opaque;
762 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
763 skip = tc->tc_skip;
764 nxt = tc->tc_nxt;
765 protoff = tc->tc_protoff;
766 mtag = (struct m_tag *) tc->tc_ptr;
767 m = (struct mbuf *) crp->crp_buf;
768
769 sav = tc->tc_sav;
770 IPSEC_ASSERT(sav != NULL, ("null SA!"));
771
772 saidx = &sav->sah->saidx;
773 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
774 saidx->dst.sa.sa_family == AF_INET6,
775 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
776
777 ahx = (struct auth_hash *) sav->tdb_authalgxform;
778
779 /* Check for crypto errors. */
780 if (crp->crp_etype) {
781 if (sav->tdb_cryptoid != 0)
782 sav->tdb_cryptoid = crp->crp_sid;
783
784 if (crp->crp_etype == EAGAIN) {
785 error = crypto_dispatch(crp);
786 return error;
787 }
788
789 V_ahstat.ahs_noxform++;
790 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
791 error = crp->crp_etype;
792 goto bad;
793 } else {
794 V_ahstat.ahs_hist[sav->alg_auth]++;
795 crypto_freereq(crp); /* No longer needed. */
796 crp = NULL;
797 }
798
799 /* Shouldn't happen... */
800 if (m == NULL) {
801 V_ahstat.ahs_crypto++;
802 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
803 error = EINVAL;
804 goto bad;
805 }
806
807 /* Figure out header size. */
808 rplen = HDRSIZE(sav);
809 authsize = AUTHSIZE(sav);
810
811 /* Copy authenticator off the packet. */
812 m_copydata(m, skip + rplen, authsize, calc);
813
814 /*
815 * If we have an mtag, we don't need to verify the authenticator --
816 * it has been verified by an IPsec-aware NIC.
817 */
818 if (mtag == NULL) {
819 ptr = (caddr_t) (tc + 1);
820
821 /* Verify authenticator. */
822 if (bcmp(ptr + skip + rplen, calc, authsize)) {
823 DPRINTF(("%s: authentication hash mismatch for packet "
824 "in SA %s/%08lx\n", __func__,
825 ipsec_address(&saidx->dst),
826 (u_long) ntohl(sav->spi)));
827 V_ahstat.ahs_badauth++;
828 error = EACCES;
829 goto bad;
830 }
831
832 /* Fix the Next Protocol field. */
833 ((u_int8_t *) ptr)[protoff] = nxt;
834
835 /* Copyback the saved (uncooked) network headers. */
836 m_copyback(m, 0, skip, ptr);
837 } else {
838 /* Fix the Next Protocol field. */
839 m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
840 }
841
842 free(tc, M_XDATA), tc = NULL; /* No longer needed */
843
844 /*
845 * Header is now authenticated.
846 */
847 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
848
849 /*
850 * Update replay sequence number, if appropriate.
851 */
852 if (sav->replay) {
853 u_int32_t seq;
854
855 m_copydata(m, skip + offsetof(struct newah, ah_seq),
856 sizeof (seq), (caddr_t) &seq);
857 if (ipsec_updatereplay(ntohl(seq), sav)) {
858 V_ahstat.ahs_replay++;
859 error = ENOBUFS; /*XXX as above*/
860 goto bad;
861 }
862 }
863
864 /*
865 * Remove the AH header and authenticator from the mbuf.
866 */
867 error = m_striphdr(m, skip, rplen + authsize);
868 if (error) {
869 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
870 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
871
872 V_ahstat.ahs_hdrops++;
873 goto bad;
874 }
875
876 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
877
878 KEY_FREESAV(&sav);
879 return error;
880 bad:
881 if (sav)
882 KEY_FREESAV(&sav);
883 if (m != NULL)
884 m_freem(m);
885 if (tc != NULL)
886 free(tc, M_XDATA);
887 if (crp != NULL)
888 crypto_freereq(crp);
889 return error;
890 }
891
892 /*
893 * AH output routine, called by ipsec[46]_process_packet().
894 */
895 static int
896 ah_output(
897 struct mbuf *m,
898 struct ipsecrequest *isr,
899 struct mbuf **mp,
900 int skip,
901 int protoff)
902 {
903 struct secasvar *sav;
904 struct auth_hash *ahx;
905 struct cryptodesc *crda;
906 struct tdb_crypto *tc;
907 struct mbuf *mi;
908 struct cryptop *crp;
909 u_int16_t iplen;
910 int error, rplen, authsize, maxpacketsize, roff;
911 u_int8_t prot;
912 struct newah *ah;
913
914 sav = isr->sav;
915 IPSEC_ASSERT(sav != NULL, ("null SA"));
916 ahx = sav->tdb_authalgxform;
917 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
918
919 V_ahstat.ahs_output++;
920
921 /* Figure out header size. */
922 rplen = HDRSIZE(sav);
923
924 /* Check for maximum packet size violations. */
925 switch (sav->sah->saidx.dst.sa.sa_family) {
926 #ifdef INET
927 case AF_INET:
928 maxpacketsize = IP_MAXPACKET;
929 break;
930 #endif /* INET */
931 #ifdef INET6
932 case AF_INET6:
933 maxpacketsize = IPV6_MAXPACKET;
934 break;
935 #endif /* INET6 */
936 default:
937 DPRINTF(("%s: unknown/unsupported protocol family %u, "
938 "SA %s/%08lx\n", __func__,
939 sav->sah->saidx.dst.sa.sa_family,
940 ipsec_address(&sav->sah->saidx.dst),
941 (u_long) ntohl(sav->spi)));
942 V_ahstat.ahs_nopf++;
943 error = EPFNOSUPPORT;
944 goto bad;
945 }
946 authsize = AUTHSIZE(sav);
947 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
948 DPRINTF(("%s: packet in SA %s/%08lx got too big "
949 "(len %u, max len %u)\n", __func__,
950 ipsec_address(&sav->sah->saidx.dst),
951 (u_long) ntohl(sav->spi),
952 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
953 V_ahstat.ahs_toobig++;
954 error = EMSGSIZE;
955 goto bad;
956 }
957
958 /* Update the counters. */
959 V_ahstat.ahs_obytes += m->m_pkthdr.len - skip;
960
961 m = m_unshare(m, M_NOWAIT);
962 if (m == NULL) {
963 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
964 ipsec_address(&sav->sah->saidx.dst),
965 (u_long) ntohl(sav->spi)));
966 V_ahstat.ahs_hdrops++;
967 error = ENOBUFS;
968 goto bad;
969 }
970
971 /* Inject AH header. */
972 mi = m_makespace(m, skip, rplen + authsize, &roff);
973 if (mi == NULL) {
974 DPRINTF(("%s: failed to inject %u byte AH header for SA "
975 "%s/%08lx\n", __func__,
976 rplen + authsize,
977 ipsec_address(&sav->sah->saidx.dst),
978 (u_long) ntohl(sav->spi)));
979 V_ahstat.ahs_hdrops++; /*XXX differs from openbsd */
980 error = ENOBUFS;
981 goto bad;
982 }
983
984 /*
985 * The AH header is guaranteed by m_makespace() to be in
986 * contiguous memory, at roff bytes offset into the returned mbuf.
987 */
988 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
989
990 /* Initialize the AH header. */
991 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
992 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
993 ah->ah_reserve = 0;
994 ah->ah_spi = sav->spi;
995
996 /* Zeroize authenticator. */
997 m_copyback(m, skip + rplen, authsize, ipseczeroes);
998
999 /* Insert packet replay counter, as requested. */
1000 if (sav->replay) {
1001 if (sav->replay->count == ~0 &&
1002 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
1003 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
1004 __func__,
1005 ipsec_address(&sav->sah->saidx.dst),
1006 (u_long) ntohl(sav->spi)));
1007 V_ahstat.ahs_wrap++;
1008 error = EINVAL;
1009 goto bad;
1010 }
1011 #ifdef REGRESSION
1012 /* Emulate replay attack when ipsec_replay is TRUE. */
1013 if (!V_ipsec_replay)
1014 #endif
1015 sav->replay->count++;
1016 ah->ah_seq = htonl(sav->replay->count);
1017 }
1018
1019 /* Get crypto descriptors. */
1020 crp = crypto_getreq(1);
1021 if (crp == NULL) {
1022 DPRINTF(("%s: failed to acquire crypto descriptors\n",
1023 __func__));
1024 V_ahstat.ahs_crypto++;
1025 error = ENOBUFS;
1026 goto bad;
1027 }
1028
1029 crda = crp->crp_desc;
1030
1031 crda->crd_skip = 0;
1032 crda->crd_inject = skip + rplen;
1033 crda->crd_len = m->m_pkthdr.len;
1034
1035 /* Authentication operation. */
1036 crda->crd_alg = ahx->type;
1037 crda->crd_key = sav->key_auth->key_data;
1038 crda->crd_klen = _KEYBITS(sav->key_auth);
1039
1040 /* Allocate IPsec-specific opaque crypto info. */
1041 tc = (struct tdb_crypto *) malloc(
1042 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1043 if (tc == NULL) {
1044 crypto_freereq(crp);
1045 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
1046 V_ahstat.ahs_crypto++;
1047 error = ENOBUFS;
1048 goto bad;
1049 }
1050
1051 /* Save the skipped portion of the packet. */
1052 m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1053
1054 /*
1055 * Fix IP header length on the header used for
1056 * authentication. We don't need to fix the original
1057 * header length as it will be fixed by our caller.
1058 */
1059 switch (sav->sah->saidx.dst.sa.sa_family) {
1060 #ifdef INET
1061 case AF_INET:
1062 bcopy(((caddr_t)(tc + 1)) +
1063 offsetof(struct ip, ip_len),
1064 (caddr_t) &iplen, sizeof(u_int16_t));
1065 iplen = htons(ntohs(iplen) + rplen + authsize);
1066 m_copyback(m, offsetof(struct ip, ip_len),
1067 sizeof(u_int16_t), (caddr_t) &iplen);
1068 break;
1069 #endif /* INET */
1070
1071 #ifdef INET6
1072 case AF_INET6:
1073 bcopy(((caddr_t)(tc + 1)) +
1074 offsetof(struct ip6_hdr, ip6_plen),
1075 (caddr_t) &iplen, sizeof(u_int16_t));
1076 iplen = htons(ntohs(iplen) + rplen + authsize);
1077 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1078 sizeof(u_int16_t), (caddr_t) &iplen);
1079 break;
1080 #endif /* INET6 */
1081 }
1082
1083 /* Fix the Next Header field in saved header. */
1084 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1085
1086 /* Update the Next Protocol field in the IP header. */
1087 prot = IPPROTO_AH;
1088 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1089
1090 /* "Massage" the packet headers for crypto processing. */
1091 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1092 skip, ahx->type, 1);
1093 if (error != 0) {
1094 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1095 free(tc, M_XDATA);
1096 crypto_freereq(crp);
1097 goto bad;
1098 }
1099
1100 /* Crypto operation descriptor. */
1101 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1102 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1103 crp->crp_buf = (caddr_t) m;
1104 crp->crp_callback = ah_output_cb;
1105 crp->crp_sid = sav->tdb_cryptoid;
1106 crp->crp_opaque = (caddr_t) tc;
1107
1108 /* These are passed as-is to the callback. */
1109 tc->tc_isr = isr;
1110 KEY_ADDREFSA(sav);
1111 tc->tc_sav = sav;
1112 tc->tc_spi = sav->spi;
1113 tc->tc_dst = sav->sah->saidx.dst;
1114 tc->tc_proto = sav->sah->saidx.proto;
1115 tc->tc_skip = skip;
1116 tc->tc_protoff = protoff;
1117
1118 return crypto_dispatch(crp);
1119 bad:
1120 if (m)
1121 m_freem(m);
1122 return (error);
1123 }
1124
1125 /*
1126 * AH output callback from the crypto driver.
1127 */
1128 static int
1129 ah_output_cb(struct cryptop *crp)
1130 {
1131 int skip, protoff, error;
1132 struct tdb_crypto *tc;
1133 struct ipsecrequest *isr;
1134 struct secasvar *sav;
1135 struct mbuf *m;
1136 caddr_t ptr;
1137 int err;
1138
1139 tc = (struct tdb_crypto *) crp->crp_opaque;
1140 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
1141 skip = tc->tc_skip;
1142 protoff = tc->tc_protoff;
1143 ptr = (caddr_t) (tc + 1);
1144 m = (struct mbuf *) crp->crp_buf;
1145
1146 isr = tc->tc_isr;
1147 IPSECREQUEST_LOCK(isr);
1148 sav = tc->tc_sav;
1149 /* With the isr lock released SA pointer can be updated. */
1150 if (sav != isr->sav) {
1151 V_ahstat.ahs_notdb++;
1152 DPRINTF(("%s: SA expired while in crypto\n", __func__));
1153 error = ENOBUFS; /*XXX*/
1154 goto bad;
1155 }
1156
1157 /* Check for crypto errors. */
1158 if (crp->crp_etype) {
1159 if (sav->tdb_cryptoid != 0)
1160 sav->tdb_cryptoid = crp->crp_sid;
1161
1162 if (crp->crp_etype == EAGAIN) {
1163 IPSECREQUEST_UNLOCK(isr);
1164 error = crypto_dispatch(crp);
1165 return error;
1166 }
1167
1168 V_ahstat.ahs_noxform++;
1169 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1170 error = crp->crp_etype;
1171 goto bad;
1172 }
1173
1174 /* Shouldn't happen... */
1175 if (m == NULL) {
1176 V_ahstat.ahs_crypto++;
1177 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1178 error = EINVAL;
1179 goto bad;
1180 }
1181 V_ahstat.ahs_hist[sav->alg_auth]++;
1182
1183 /*
1184 * Copy original headers (with the new protocol number) back
1185 * in place.
1186 */
1187 m_copyback(m, 0, skip, ptr);
1188
1189 /* No longer needed. */
1190 free(tc, M_XDATA);
1191 crypto_freereq(crp);
1192
1193 #ifdef REGRESSION
1194 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1195 if (V_ipsec_integrity) {
1196 int alen;
1197
1198 /*
1199 * Corrupt HMAC if we want to test integrity verification of
1200 * the other side.
1201 */
1202 alen = AUTHSIZE(sav);
1203 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1204 }
1205 #endif
1206
1207 /* NB: m is reclaimed by ipsec_process_done. */
1208 err = ipsec_process_done(m, isr);
1209 KEY_FREESAV(&sav);
1210 IPSECREQUEST_UNLOCK(isr);
1211 return err;
1212 bad:
1213 if (sav)
1214 KEY_FREESAV(&sav);
1215 IPSECREQUEST_UNLOCK(isr);
1216 if (m)
1217 m_freem(m);
1218 free(tc, M_XDATA);
1219 crypto_freereq(crp);
1220 return error;
1221 }
1222
1223 static struct xformsw ah_xformsw = {
1224 XF_AH, XFT_AUTH, "IPsec AH",
1225 ah_init, ah_zeroize, ah_input, ah_output,
1226 };
1227
1228 static void
1229 ah_attach(void)
1230 {
1231
1232 xform_register(&ah_xformsw);
1233 }
1234
1235 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
Cache object: 8c3f2c7e9da674dab531264c2cb3b9fa
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