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
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/ip.h>
55 #include <netinet/ip_ecn.h>
56 #include <netinet/ip6.h>
57
58 #include <net/route.h>
59 #include <netipsec/ipsec.h>
60 #include <netipsec/ah.h>
61 #include <netipsec/ah_var.h>
62 #include <netipsec/xform.h>
63
64 #ifdef INET6
65 #include <netinet6/ip6_var.h>
66 #include <netipsec/ipsec6.h>
67 #include <netinet6/ip6_ecn.h>
68 #endif
69
70 #include <netipsec/key.h>
71 #include <netipsec/key_debug.h>
72
73 #include <opencrypto/cryptodev.h>
74
75 /*
76 * Return header size in bytes. The old protocol did not support
77 * the replay counter; the new protocol always includes the counter.
78 */
79 #define HDRSIZE(sav) \
80 (((sav)->flags & SADB_X_EXT_OLD) ? \
81 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
82 /*
83 * Return authenticator size in bytes. The old protocol is known
84 * to use a fixed 16-byte authenticator. The new algorithm gets
85 * this size from the xform but is (currently) always 12.
86 */
87 #define AUTHSIZE(sav) \
88 ((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize)
89
90 int ah_enable = 1; /* control flow of packets with AH */
91 int ah_cleartos = 1; /* clear ip_tos when doing AH calc */
92 struct ahstat ahstat;
93
94 SYSCTL_DECL(_net_inet_ah);
95 SYSCTL_INT(_net_inet_ah, OID_AUTO,
96 ah_enable, CTLFLAG_RW, &ah_enable, 0, "");
97 SYSCTL_INT(_net_inet_ah, OID_AUTO,
98 ah_cleartos, CTLFLAG_RW, &ah_cleartos, 0, "");
99 SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
100 stats, CTLFLAG_RD, &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 /*
108 * NB: this is public for use by the PF_KEY support.
109 */
110 struct auth_hash *
111 ah_algorithm_lookup(int alg)
112 {
113 if (alg >= AH_ALG_MAX)
114 return NULL;
115 switch (alg) {
116 case SADB_X_AALG_NULL:
117 return &auth_hash_null;
118 case SADB_AALG_MD5HMAC:
119 return &auth_hash_hmac_md5_96;
120 case SADB_AALG_SHA1HMAC:
121 return &auth_hash_hmac_sha1_96;
122 case SADB_X_AALG_RIPEMD160HMAC:
123 return &auth_hash_hmac_ripemd_160_96;
124 case SADB_X_AALG_MD5:
125 return &auth_hash_key_md5;
126 case SADB_X_AALG_SHA:
127 return &auth_hash_key_sha1;
128 case SADB_X_AALG_SHA2_256:
129 return &auth_hash_hmac_sha2_256;
130 case SADB_X_AALG_SHA2_384:
131 return &auth_hash_hmac_sha2_384;
132 case SADB_X_AALG_SHA2_512:
133 return &auth_hash_hmac_sha2_512;
134 }
135 return NULL;
136 }
137
138 size_t
139 ah_hdrsiz(struct secasvar *sav)
140 {
141 size_t size;
142
143 if (sav != NULL) {
144 int authsize;
145 KASSERT(sav->tdb_authalgxform != NULL,
146 ("ah_hdrsiz: null xform"));
147 /*XXX not right for null algorithm--does it matter??*/
148 authsize = AUTHSIZE(sav);
149 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
150 } else {
151 /* default guess */
152 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
153 }
154 return size;
155 }
156
157 /*
158 * NB: public for use by esp_init.
159 */
160 int
161 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
162 {
163 struct auth_hash *thash;
164 int keylen;
165
166 thash = ah_algorithm_lookup(sav->alg_auth);
167 if (thash == NULL) {
168 DPRINTF(("ah_init: unsupported authentication algorithm %u\n",
169 sav->alg_auth));
170 return EINVAL;
171 }
172 /*
173 * Verify the replay state block allocation is consistent with
174 * the protocol type. We check here so we can make assumptions
175 * later during protocol processing.
176 */
177 /* NB: replay state is setup elsewhere (sigh) */
178 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
179 DPRINTF(("ah_init: replay state block inconsistency, "
180 "%s algorithm %s replay state\n",
181 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
182 sav->replay == NULL ? "without" : "with"));
183 return EINVAL;
184 }
185 if (sav->key_auth == NULL) {
186 DPRINTF(("ah_init: no authentication key for %s "
187 "algorithm\n", thash->name));
188 return EINVAL;
189 }
190 keylen = _KEYLEN(sav->key_auth);
191 if (keylen != thash->keysize && thash->keysize != 0) {
192 DPRINTF(("ah_init: invalid keylength %d, algorithm "
193 "%s requires keysize %d\n",
194 keylen, thash->name, thash->keysize));
195 return EINVAL;
196 }
197
198 sav->tdb_xform = xsp;
199 sav->tdb_authalgxform = thash;
200
201 /* Initialize crypto session. */
202 bzero(cria, sizeof (*cria));
203 cria->cri_alg = sav->tdb_authalgxform->type;
204 cria->cri_klen = _KEYBITS(sav->key_auth);
205 cria->cri_key = _KEYBUF(sav->key_auth);
206
207 return 0;
208 }
209
210 /*
211 * ah_init() is called when an SPI is being set up.
212 */
213 static int
214 ah_init(struct secasvar *sav, struct xformsw *xsp)
215 {
216 struct cryptoini cria;
217 int error;
218
219 error = ah_init0(sav, xsp, &cria);
220 return error ? error :
221 crypto_newsession(&sav->tdb_cryptoid, &cria, crypto_support);
222 }
223
224 /*
225 * Paranoia.
226 *
227 * NB: public for use by esp_zeroize (XXX).
228 */
229 int
230 ah_zeroize(struct secasvar *sav)
231 {
232 int err;
233
234 if (sav->key_auth)
235 bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
236
237 err = crypto_freesession(sav->tdb_cryptoid);
238 sav->tdb_cryptoid = 0;
239 sav->tdb_authalgxform = NULL;
240 sav->tdb_xform = NULL;
241 return err;
242 }
243
244 /*
245 * Massage IPv4/IPv6 headers for AH processing.
246 */
247 static int
248 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
249 {
250 struct mbuf *m = *m0;
251 unsigned char *ptr;
252 int off, count;
253
254 #ifdef INET
255 struct ip *ip;
256 #endif /* INET */
257
258 #ifdef INET6
259 struct ip6_ext *ip6e;
260 struct ip6_hdr ip6;
261 int alloc, len, ad;
262 #endif /* INET6 */
263
264 switch (proto) {
265 #ifdef INET
266 case AF_INET:
267 /*
268 * This is the least painful way of dealing with IPv4 header
269 * and option processing -- just make sure they're in
270 * contiguous memory.
271 */
272 *m0 = m = m_pullup(m, skip);
273 if (m == NULL) {
274 DPRINTF(("ah_massage_headers: m_pullup failed\n"));
275 return ENOBUFS;
276 }
277
278 /* Fix the IP header */
279 ip = mtod(m, struct ip *);
280 if (ah_cleartos)
281 ip->ip_tos = 0;
282 ip->ip_ttl = 0;
283 ip->ip_sum = 0;
284
285 /*
286 * On input, fix ip_len which has been byte-swapped
287 * at ip_input().
288 */
289 if (!out) {
290 ip->ip_len = htons(ip->ip_len + skip);
291
292 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
293 ip->ip_off = htons(ip->ip_off & IP_DF);
294 else
295 ip->ip_off = 0;
296 } else {
297 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
298 ip->ip_off = htons(ntohs(ip->ip_off) & IP_DF);
299 else
300 ip->ip_off = 0;
301 }
302
303 ptr = mtod(m, unsigned char *) + sizeof(struct ip);
304
305 /* IPv4 option processing */
306 for (off = sizeof(struct ip); off < skip;) {
307 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
308 off + 1 < skip)
309 ;
310 else {
311 DPRINTF(("ah_massage_headers: illegal IPv4 "
312 "option length for option %d\n",
313 ptr[off]));
314
315 m_freem(m);
316 return EINVAL;
317 }
318
319 switch (ptr[off]) {
320 case IPOPT_EOL:
321 off = skip; /* End the loop. */
322 break;
323
324 case IPOPT_NOP:
325 off++;
326 break;
327
328 case IPOPT_SECURITY: /* 0x82 */
329 case 0x85: /* Extended security. */
330 case 0x86: /* Commercial security. */
331 case 0x94: /* Router alert */
332 case 0x95: /* RFC1770 */
333 /* Sanity check for option length. */
334 if (ptr[off + 1] < 2) {
335 DPRINTF(("ah_massage_headers: "
336 "illegal IPv4 option length for "
337 "option %d\n", ptr[off]));
338
339 m_freem(m);
340 return EINVAL;
341 }
342
343 off += ptr[off + 1];
344 break;
345
346 case IPOPT_LSRR:
347 case IPOPT_SSRR:
348 /* Sanity check for option length. */
349 if (ptr[off + 1] < 2) {
350 DPRINTF(("ah_massage_headers: "
351 "illegal IPv4 option length for "
352 "option %d\n", ptr[off]));
353
354 m_freem(m);
355 return EINVAL;
356 }
357
358 /*
359 * On output, if we have either of the
360 * source routing options, we should
361 * swap the destination address of the
362 * IP header with the last address
363 * specified in the option, as that is
364 * what the destination's IP header
365 * will look like.
366 */
367 if (out)
368 bcopy(ptr + off + ptr[off + 1] -
369 sizeof(struct in_addr),
370 &(ip->ip_dst), sizeof(struct in_addr));
371
372 /* Fall through */
373 default:
374 /* Sanity check for option length. */
375 if (ptr[off + 1] < 2) {
376 DPRINTF(("ah_massage_headers: "
377 "illegal IPv4 option length for "
378 "option %d\n", ptr[off]));
379 m_freem(m);
380 return EINVAL;
381 }
382
383 /* Zeroize all other options. */
384 count = ptr[off + 1];
385 bcopy(ipseczeroes, ptr, count);
386 off += count;
387 break;
388 }
389
390 /* Sanity check. */
391 if (off > skip) {
392 DPRINTF(("ah_massage_headers(): malformed "
393 "IPv4 options header\n"));
394
395 m_freem(m);
396 return EINVAL;
397 }
398 }
399
400 break;
401 #endif /* INET */
402
403 #ifdef INET6
404 case AF_INET6: /* Ugly... */
405 /* Copy and "cook" the IPv6 header. */
406 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
407
408 /* We don't do IPv6 Jumbograms. */
409 if (ip6.ip6_plen == 0) {
410 DPRINTF(("ah_massage_headers: unsupported IPv6 jumbogram\n"));
411 m_freem(m);
412 return EMSGSIZE;
413 }
414
415 ip6.ip6_flow = 0;
416 ip6.ip6_hlim = 0;
417 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
418 ip6.ip6_vfc |= IPV6_VERSION;
419
420 /* Scoped address handling. */
421 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
422 ip6.ip6_src.s6_addr16[1] = 0;
423 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
424 ip6.ip6_dst.s6_addr16[1] = 0;
425
426 /* Done with IPv6 header. */
427 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
428
429 /* Let's deal with the remaining headers (if any). */
430 if (skip - sizeof(struct ip6_hdr) > 0) {
431 if (m->m_len <= skip) {
432 ptr = (unsigned char *) malloc(
433 skip - sizeof(struct ip6_hdr),
434 M_XDATA, M_NOWAIT);
435 if (ptr == NULL) {
436 DPRINTF(("ah_massage_headers: failed "
437 "to allocate memory for IPv6 "
438 "headers\n"));
439 m_freem(m);
440 return ENOBUFS;
441 }
442
443 /*
444 * Copy all the protocol headers after
445 * the IPv6 header.
446 */
447 m_copydata(m, sizeof(struct ip6_hdr),
448 skip - sizeof(struct ip6_hdr), ptr);
449 alloc = 1;
450 } else {
451 /* No need to allocate memory. */
452 ptr = mtod(m, unsigned char *) +
453 sizeof(struct ip6_hdr);
454 alloc = 0;
455 }
456 } else
457 break;
458
459 off = ip6.ip6_nxt & 0xff; /* Next header type. */
460
461 for (len = 0; len < skip - sizeof(struct ip6_hdr);)
462 switch (off) {
463 case IPPROTO_HOPOPTS:
464 case IPPROTO_DSTOPTS:
465 ip6e = (struct ip6_ext *) (ptr + len);
466
467 /*
468 * Process the mutable/immutable
469 * options -- borrows heavily from the
470 * KAME code.
471 */
472 for (count = len + sizeof(struct ip6_ext);
473 count < len + ((ip6e->ip6e_len + 1) << 3);) {
474 if (ptr[count] == IP6OPT_PAD1) {
475 count++;
476 continue; /* Skip padding. */
477 }
478
479 /* Sanity check. */
480 if (count > len +
481 ((ip6e->ip6e_len + 1) << 3)) {
482 m_freem(m);
483
484 /* Free, if we allocated. */
485 if (alloc)
486 FREE(ptr, M_XDATA);
487 return EINVAL;
488 }
489
490 ad = ptr[count + 1];
491
492 /* If mutable option, zeroize. */
493 if (ptr[count] & IP6OPT_MUTABLE)
494 bcopy(ipseczeroes, ptr + count,
495 ptr[count + 1]);
496
497 count += ad;
498
499 /* Sanity check. */
500 if (count >
501 skip - sizeof(struct ip6_hdr)) {
502 m_freem(m);
503
504 /* Free, if we allocated. */
505 if (alloc)
506 FREE(ptr, M_XDATA);
507 return EINVAL;
508 }
509 }
510
511 /* Advance. */
512 len += ((ip6e->ip6e_len + 1) << 3);
513 off = ip6e->ip6e_nxt;
514 break;
515
516 case IPPROTO_ROUTING:
517 /*
518 * Always include routing headers in
519 * computation.
520 */
521 ip6e = (struct ip6_ext *) (ptr + len);
522 len += ((ip6e->ip6e_len + 1) << 3);
523 off = ip6e->ip6e_nxt;
524 break;
525
526 default:
527 DPRINTF(("ah_massage_headers: unexpected "
528 "IPv6 header type %d", off));
529 if (alloc)
530 FREE(ptr, M_XDATA);
531 m_freem(m);
532 return EINVAL;
533 }
534
535 /* Copyback and free, if we allocated. */
536 if (alloc) {
537 m_copyback(m, sizeof(struct ip6_hdr),
538 skip - sizeof(struct ip6_hdr), ptr);
539 free(ptr, M_XDATA);
540 }
541
542 break;
543 #endif /* INET6 */
544 }
545
546 return 0;
547 }
548
549 /*
550 * ah_input() gets called to verify that an input packet
551 * passes authentication.
552 */
553 static int
554 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
555 {
556 struct auth_hash *ahx;
557 struct tdb_ident *tdbi;
558 struct tdb_crypto *tc;
559 struct m_tag *mtag;
560 struct newah *ah;
561 int hl, rplen, authsize;
562
563 struct cryptodesc *crda;
564 struct cryptop *crp;
565
566 SPLASSERT(net, "ah_input");
567
568 KASSERT(sav != NULL, ("ah_input: null SA"));
569 KASSERT(sav->key_auth != NULL,
570 ("ah_input: null authentication key"));
571 KASSERT(sav->tdb_authalgxform != NULL,
572 ("ah_input: null authentication xform"));
573
574 /* Figure out header size. */
575 rplen = HDRSIZE(sav);
576
577 /* XXX don't pullup, just copy header */
578 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
579 if (ah == NULL) {
580 DPRINTF(("ah_input: cannot pullup header\n"));
581 ahstat.ahs_hdrops++; /*XXX*/
582 m_freem(m);
583 return ENOBUFS;
584 }
585
586 /* Check replay window, if applicable. */
587 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
588 ahstat.ahs_replay++;
589 DPRINTF(("ah_input: packet replay failure: %s\n",
590 ipsec_logsastr(sav)));
591 m_freem(m);
592 return ENOBUFS;
593 }
594
595 /* Verify AH header length. */
596 hl = ah->ah_len * sizeof (u_int32_t);
597 ahx = sav->tdb_authalgxform;
598 authsize = AUTHSIZE(sav);
599 if (hl != authsize + rplen - sizeof (struct ah)) {
600 DPRINTF(("ah_input: bad authenticator length %u (expecting %lu)"
601 " for packet in SA %s/%08lx\n",
602 hl, (u_long) (authsize + rplen - sizeof (struct ah)),
603 ipsec_address(&sav->sah->saidx.dst),
604 (u_long) ntohl(sav->spi)));
605 ahstat.ahs_badauthl++;
606 m_freem(m);
607 return EACCES;
608 }
609 ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl;
610
611 /* Get crypto descriptors. */
612 crp = crypto_getreq(1);
613 if (crp == NULL) {
614 DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
615 ahstat.ahs_crypto++;
616 m_freem(m);
617 return ENOBUFS;
618 }
619
620 crda = crp->crp_desc;
621 KASSERT(crda != NULL, ("ah_input: null crypto descriptor"));
622
623 crda->crd_skip = 0;
624 crda->crd_len = m->m_pkthdr.len;
625 crda->crd_inject = skip + rplen;
626
627 /* Authentication operation. */
628 crda->crd_alg = ahx->type;
629 crda->crd_key = _KEYBUF(sav->key_auth);
630 crda->crd_klen = _KEYBITS(sav->key_auth);
631
632 /* Find out if we've already done crypto. */
633 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
634 mtag != NULL;
635 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
636 tdbi = (struct tdb_ident *) (mtag + 1);
637 if (tdbi->proto == sav->sah->saidx.proto &&
638 tdbi->spi == sav->spi &&
639 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
640 sizeof (union sockaddr_union)))
641 break;
642 }
643
644 /* Allocate IPsec-specific opaque crypto info. */
645 if (mtag == NULL) {
646 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
647 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
648 } else {
649 /* Hash verification has already been done successfully. */
650 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
651 M_XDATA, M_NOWAIT|M_ZERO);
652 }
653 if (tc == NULL) {
654 DPRINTF(("ah_input: failed to allocate tdb_crypto\n"));
655 ahstat.ahs_crypto++;
656 crypto_freereq(crp);
657 m_freem(m);
658 return ENOBUFS;
659 }
660
661 /* Only save information if crypto processing is needed. */
662 if (mtag == NULL) {
663 int error;
664
665 /*
666 * Save the authenticator, the skipped portion of the packet,
667 * and the AH header.
668 */
669 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
670
671 /* Zeroize the authenticator on the packet. */
672 m_copyback(m, skip + rplen, authsize, ipseczeroes);
673
674 /* "Massage" the packet headers for crypto processing. */
675 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
676 skip, ahx->type, 0);
677 if (error != 0) {
678 /* NB: mbuf is free'd by ah_massage_headers */
679 ahstat.ahs_hdrops++;
680 free(tc, M_XDATA);
681 crypto_freereq(crp);
682 return error;
683 }
684 }
685
686 /* Crypto operation descriptor. */
687 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
688 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
689 crp->crp_buf = (caddr_t) m;
690 crp->crp_callback = ah_input_cb;
691 crp->crp_sid = sav->tdb_cryptoid;
692 crp->crp_opaque = (caddr_t) tc;
693
694 /* These are passed as-is to the callback. */
695 tc->tc_spi = sav->spi;
696 tc->tc_dst = sav->sah->saidx.dst;
697 tc->tc_proto = sav->sah->saidx.proto;
698 tc->tc_nxt = ah->ah_nxt;
699 tc->tc_protoff = protoff;
700 tc->tc_skip = skip;
701 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
702
703 if (mtag == NULL)
704 return crypto_dispatch(crp);
705 else
706 return ah_input_cb(crp);
707 }
708
709 #ifdef INET6
710 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
711 if (saidx->dst.sa.sa_family == AF_INET6) { \
712 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
713 } else { \
714 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
715 } \
716 } while (0)
717 #else
718 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
719 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
720 #endif
721
722 /*
723 * AH input callback from the crypto driver.
724 */
725 static int
726 ah_input_cb(struct cryptop *crp)
727 {
728 int rplen, error, skip, protoff;
729 unsigned char calc[AH_ALEN_MAX];
730 struct mbuf *m;
731 struct cryptodesc *crd;
732 struct auth_hash *ahx;
733 struct tdb_crypto *tc;
734 struct m_tag *mtag;
735 struct secasvar *sav;
736 struct secasindex *saidx;
737 u_int8_t nxt;
738 caddr_t ptr;
739 int s, authsize;
740
741 crd = crp->crp_desc;
742
743 tc = (struct tdb_crypto *) crp->crp_opaque;
744 KASSERT(tc != NULL, ("ah_input_cb: null opaque crypto data area!"));
745 skip = tc->tc_skip;
746 nxt = tc->tc_nxt;
747 protoff = tc->tc_protoff;
748 mtag = (struct m_tag *) tc->tc_ptr;
749 m = (struct mbuf *) crp->crp_buf;
750
751 s = splnet();
752
753 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
754 if (sav == NULL) {
755 ahstat.ahs_notdb++;
756 DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
757 error = ENOBUFS; /*XXX*/
758 goto bad;
759 }
760
761 saidx = &sav->sah->saidx;
762 KASSERT(saidx->dst.sa.sa_family == AF_INET ||
763 saidx->dst.sa.sa_family == AF_INET6,
764 ("ah_input_cb: unexpected protocol family %u",
765 saidx->dst.sa.sa_family));
766
767 ahx = (struct auth_hash *) sav->tdb_authalgxform;
768
769 /* Check for crypto errors. */
770 if (crp->crp_etype) {
771 if (sav->tdb_cryptoid != 0)
772 sav->tdb_cryptoid = crp->crp_sid;
773
774 if (crp->crp_etype == EAGAIN)
775 return crypto_dispatch(crp);
776
777 ahstat.ahs_noxform++;
778 DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
779 error = crp->crp_etype;
780 goto bad;
781 } else {
782 ahstat.ahs_hist[sav->alg_auth]++;
783 crypto_freereq(crp); /* No longer needed. */
784 crp = NULL;
785 }
786
787 /* Shouldn't happen... */
788 if (m == NULL) {
789 ahstat.ahs_crypto++;
790 DPRINTF(("ah_input_cb: bogus returned buffer from crypto\n"));
791 error = EINVAL;
792 goto bad;
793 }
794
795 /* Figure out header size. */
796 rplen = HDRSIZE(sav);
797 authsize = AUTHSIZE(sav);
798
799 /* Copy authenticator off the packet. */
800 m_copydata(m, skip + rplen, authsize, calc);
801
802 /*
803 * If we have an mtag, we don't need to verify the authenticator --
804 * it has been verified by an IPsec-aware NIC.
805 */
806 if (mtag == NULL) {
807 ptr = (caddr_t) (tc + 1);
808
809 /* Verify authenticator. */
810 if (bcmp(ptr + skip + rplen, calc, authsize)) {
811 DPRINTF(("ah_input: authentication hash mismatch "
812 "for packet in SA %s/%08lx\n",
813 ipsec_address(&saidx->dst),
814 (u_long) ntohl(sav->spi)));
815 ahstat.ahs_badauth++;
816 error = EACCES;
817 goto bad;
818 }
819
820 /* Fix the Next Protocol field. */
821 ((u_int8_t *) ptr)[protoff] = nxt;
822
823 /* Copyback the saved (uncooked) network headers. */
824 m_copyback(m, 0, skip, ptr);
825 } else {
826 /* Fix the Next Protocol field. */
827 m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
828 }
829
830 free(tc, M_XDATA), tc = NULL; /* No longer needed */
831
832 /*
833 * Header is now authenticated.
834 */
835 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
836
837 /*
838 * Update replay sequence number, if appropriate.
839 */
840 if (sav->replay) {
841 u_int32_t seq;
842
843 m_copydata(m, skip + offsetof(struct newah, ah_seq),
844 sizeof (seq), (caddr_t) &seq);
845 if (ipsec_updatereplay(ntohl(seq), sav)) {
846 ahstat.ahs_replay++;
847 error = ENOBUFS; /*XXX as above*/
848 goto bad;
849 }
850 }
851
852 /*
853 * Remove the AH header and authenticator from the mbuf.
854 */
855 error = m_striphdr(m, skip, rplen + authsize);
856 if (error) {
857 DPRINTF(("ah_input_cb: mangled mbuf chain for SA %s/%08lx\n",
858 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
859
860 ahstat.ahs_hdrops++;
861 goto bad;
862 }
863
864 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
865
866 KEY_FREESAV(&sav);
867 splx(s);
868 return error;
869 bad:
870 if (sav)
871 KEY_FREESAV(&sav);
872 splx(s);
873 if (m != NULL)
874 m_freem(m);
875 if (tc != NULL)
876 free(tc, M_XDATA);
877 if (crp != NULL)
878 crypto_freereq(crp);
879 return error;
880 }
881
882 /*
883 * AH output routine, called by ipsec[46]_process_packet().
884 */
885 static int
886 ah_output(
887 struct mbuf *m,
888 struct ipsecrequest *isr,
889 struct mbuf **mp,
890 int skip,
891 int protoff)
892 {
893 struct secasvar *sav;
894 struct auth_hash *ahx;
895 struct cryptodesc *crda;
896 struct tdb_crypto *tc;
897 struct mbuf *mi;
898 struct cryptop *crp;
899 u_int16_t iplen;
900 int error, rplen, authsize, maxpacketsize, roff;
901 u_int8_t prot;
902 struct newah *ah;
903
904 SPLASSERT(net, "ah_output");
905
906 sav = isr->sav;
907 KASSERT(sav != NULL, ("ah_output: null SA"));
908 ahx = sav->tdb_authalgxform;
909 KASSERT(ahx != NULL, ("ah_output: null authentication xform"));
910
911 ahstat.ahs_output++;
912
913 /* Figure out header size. */
914 rplen = HDRSIZE(sav);
915
916 /* Check for maximum packet size violations. */
917 switch (sav->sah->saidx.dst.sa.sa_family) {
918 #ifdef INET
919 case AF_INET:
920 maxpacketsize = IP_MAXPACKET;
921 break;
922 #endif /* INET */
923 #ifdef INET6
924 case AF_INET6:
925 maxpacketsize = IPV6_MAXPACKET;
926 break;
927 #endif /* INET6 */
928 default:
929 DPRINTF(("ah_output: unknown/unsupported protocol "
930 "family %u, SA %s/%08lx\n",
931 sav->sah->saidx.dst.sa.sa_family,
932 ipsec_address(&sav->sah->saidx.dst),
933 (u_long) ntohl(sav->spi)));
934 ahstat.ahs_nopf++;
935 error = EPFNOSUPPORT;
936 goto bad;
937 }
938 authsize = AUTHSIZE(sav);
939 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
940 DPRINTF(("ah_output: packet in SA %s/%08lx got too big "
941 "(len %u, max len %u)\n",
942 ipsec_address(&sav->sah->saidx.dst),
943 (u_long) ntohl(sav->spi),
944 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
945 ahstat.ahs_toobig++;
946 error = EMSGSIZE;
947 goto bad;
948 }
949
950 /* Update the counters. */
951 ahstat.ahs_obytes += m->m_pkthdr.len - skip;
952
953 m = m_clone(m);
954 if (m == NULL) {
955 DPRINTF(("ah_output: cannot clone mbuf chain, SA %s/%08lx\n",
956 ipsec_address(&sav->sah->saidx.dst),
957 (u_long) ntohl(sav->spi)));
958 ahstat.ahs_hdrops++;
959 error = ENOBUFS;
960 goto bad;
961 }
962
963 /* Inject AH header. */
964 mi = m_makespace(m, skip, rplen + authsize, &roff);
965 if (mi == NULL) {
966 DPRINTF(("ah_output: failed to inject %u byte AH header for SA "
967 "%s/%08lx\n",
968 rplen + authsize,
969 ipsec_address(&sav->sah->saidx.dst),
970 (u_long) ntohl(sav->spi)));
971 ahstat.ahs_hdrops++; /*XXX differs from openbsd */
972 error = ENOBUFS;
973 goto bad;
974 }
975
976 /*
977 * The AH header is guaranteed by m_makespace() to be in
978 * contiguous memory, at roff bytes offset into the returned mbuf.
979 */
980 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
981
982 /* Initialize the AH header. */
983 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
984 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
985 ah->ah_reserve = 0;
986 ah->ah_spi = sav->spi;
987
988 /* Zeroize authenticator. */
989 m_copyback(m, skip + rplen, authsize, ipseczeroes);
990
991 /* Insert packet replay counter, as requested. */
992 if (sav->replay) {
993 if (sav->replay->count == ~0 &&
994 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
995 DPRINTF(("ah_output: replay counter wrapped for SA "
996 "%s/%08lx\n",
997 ipsec_address(&sav->sah->saidx.dst),
998 (u_long) ntohl(sav->spi)));
999 ahstat.ahs_wrap++;
1000 error = EINVAL;
1001 goto bad;
1002 }
1003 sav->replay->count++;
1004 ah->ah_seq = htonl(sav->replay->count);
1005 }
1006
1007 /* Get crypto descriptors. */
1008 crp = crypto_getreq(1);
1009 if (crp == NULL) {
1010 DPRINTF(("ah_output: failed to acquire crypto descriptors\n"));
1011 ahstat.ahs_crypto++;
1012 error = ENOBUFS;
1013 goto bad;
1014 }
1015
1016 crda = crp->crp_desc;
1017
1018 crda->crd_skip = 0;
1019 crda->crd_inject = skip + rplen;
1020 crda->crd_len = m->m_pkthdr.len;
1021
1022 /* Authentication operation. */
1023 crda->crd_alg = ahx->type;
1024 crda->crd_key = _KEYBUF(sav->key_auth);
1025 crda->crd_klen = _KEYBITS(sav->key_auth);
1026
1027 /* Allocate IPsec-specific opaque crypto info. */
1028 tc = (struct tdb_crypto *) malloc(
1029 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1030 if (tc == NULL) {
1031 crypto_freereq(crp);
1032 DPRINTF(("ah_output: failed to allocate tdb_crypto\n"));
1033 ahstat.ahs_crypto++;
1034 error = ENOBUFS;
1035 goto bad;
1036 }
1037
1038 /* Save the skipped portion of the packet. */
1039 m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1040
1041 /*
1042 * Fix IP header length on the header used for
1043 * authentication. We don't need to fix the original
1044 * header length as it will be fixed by our caller.
1045 */
1046 switch (sav->sah->saidx.dst.sa.sa_family) {
1047 #ifdef INET
1048 case AF_INET:
1049 bcopy(((caddr_t)(tc + 1)) +
1050 offsetof(struct ip, ip_len),
1051 (caddr_t) &iplen, sizeof(u_int16_t));
1052 iplen = htons(ntohs(iplen) + rplen + authsize);
1053 m_copyback(m, offsetof(struct ip, ip_len),
1054 sizeof(u_int16_t), (caddr_t) &iplen);
1055 break;
1056 #endif /* INET */
1057
1058 #ifdef INET6
1059 case AF_INET6:
1060 bcopy(((caddr_t)(tc + 1)) +
1061 offsetof(struct ip6_hdr, ip6_plen),
1062 (caddr_t) &iplen, sizeof(u_int16_t));
1063 iplen = htons(ntohs(iplen) + rplen + authsize);
1064 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1065 sizeof(u_int16_t), (caddr_t) &iplen);
1066 break;
1067 #endif /* INET6 */
1068 }
1069
1070 /* Fix the Next Header field in saved header. */
1071 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1072
1073 /* Update the Next Protocol field in the IP header. */
1074 prot = IPPROTO_AH;
1075 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1076
1077 /* "Massage" the packet headers for crypto processing. */
1078 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1079 skip, ahx->type, 1);
1080 if (error != 0) {
1081 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1082 free(tc, M_XDATA);
1083 crypto_freereq(crp);
1084 goto bad;
1085 }
1086
1087 /* Crypto operation descriptor. */
1088 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1089 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1090 crp->crp_buf = (caddr_t) m;
1091 crp->crp_callback = ah_output_cb;
1092 crp->crp_sid = sav->tdb_cryptoid;
1093 crp->crp_opaque = (caddr_t) tc;
1094
1095 /* These are passed as-is to the callback. */
1096 tc->tc_isr = isr;
1097 tc->tc_spi = sav->spi;
1098 tc->tc_dst = sav->sah->saidx.dst;
1099 tc->tc_proto = sav->sah->saidx.proto;
1100 tc->tc_skip = skip;
1101 tc->tc_protoff = protoff;
1102
1103 return crypto_dispatch(crp);
1104 bad:
1105 if (m)
1106 m_freem(m);
1107 return (error);
1108 }
1109
1110 /*
1111 * AH output callback from the crypto driver.
1112 */
1113 static int
1114 ah_output_cb(struct cryptop *crp)
1115 {
1116 int skip, protoff, error;
1117 struct tdb_crypto *tc;
1118 struct ipsecrequest *isr;
1119 struct secasvar *sav;
1120 struct mbuf *m;
1121 caddr_t ptr;
1122 int s, err;
1123
1124 tc = (struct tdb_crypto *) crp->crp_opaque;
1125 KASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
1126 skip = tc->tc_skip;
1127 protoff = tc->tc_protoff;
1128 ptr = (caddr_t) (tc + 1);
1129 m = (struct mbuf *) crp->crp_buf;
1130
1131 s = splnet();
1132
1133 isr = tc->tc_isr;
1134 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
1135 if (sav == NULL) {
1136 ahstat.ahs_notdb++;
1137 DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
1138 error = ENOBUFS; /*XXX*/
1139 goto bad;
1140 }
1141 KASSERT(isr->sav == sav, ("ah_output_cb: SA changed\n"));
1142
1143 /* Check for crypto errors. */
1144 if (crp->crp_etype) {
1145 if (sav->tdb_cryptoid != 0)
1146 sav->tdb_cryptoid = crp->crp_sid;
1147
1148 if (crp->crp_etype == EAGAIN) {
1149 KEY_FREESAV(&sav);
1150 splx(s);
1151 return crypto_dispatch(crp);
1152 }
1153
1154 ahstat.ahs_noxform++;
1155 DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
1156 error = crp->crp_etype;
1157 goto bad;
1158 }
1159
1160 /* Shouldn't happen... */
1161 if (m == NULL) {
1162 ahstat.ahs_crypto++;
1163 DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
1164 error = EINVAL;
1165 goto bad;
1166 }
1167 ahstat.ahs_hist[sav->alg_auth]++;
1168
1169 /*
1170 * Copy original headers (with the new protocol number) back
1171 * in place.
1172 */
1173 m_copyback(m, 0, skip, ptr);
1174
1175 /* No longer needed. */
1176 free(tc, M_XDATA);
1177 crypto_freereq(crp);
1178
1179 /* NB: m is reclaimed by ipsec_process_done. */
1180 err = ipsec_process_done(m, isr);
1181 KEY_FREESAV(&sav);
1182 splx(s);
1183 return err;
1184 bad:
1185 if (sav)
1186 KEY_FREESAV(&sav);
1187 splx(s);
1188 if (m)
1189 m_freem(m);
1190 free(tc, M_XDATA);
1191 crypto_freereq(crp);
1192 return error;
1193 }
1194
1195 static struct xformsw ah_xformsw = {
1196 XF_AH, XFT_AUTH, "IPsec AH",
1197 ah_init, ah_zeroize, ah_input, ah_output,
1198 };
1199
1200 static void
1201 ah_attach(void)
1202 {
1203 xform_register(&ah_xformsw);
1204 }
1205 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
Cache object: 04fd0abb1725b101bf7e621832e33acb
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