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 <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 use 12-byte
85 * authenticator.
86 */
87 #define AUTHSIZE(sav) ah_authsize(sav)
88
89 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
90 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
91 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat);
92 VNET_PCPUSTAT_SYSINIT(ahstat);
93
94 #ifdef VIMAGE
95 VNET_PCPUSTAT_SYSUNINIT(ahstat);
96 #endif /* VIMAGE */
97
98 #ifdef INET
99 SYSCTL_DECL(_net_inet_ah);
100 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO,
101 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
102 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO,
103 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
104 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat,
105 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)");
106 #endif
107
108 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
109
110 static int ah_input_cb(struct cryptop*);
111 static int ah_output_cb(struct cryptop*);
112
113 static int
ah_authsize(struct secasvar * sav)114 ah_authsize(struct secasvar *sav)
115 {
116
117 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__));
118
119 if (sav->flags & SADB_X_EXT_OLD)
120 return 16;
121
122 switch (sav->alg_auth) {
123 case SADB_X_AALG_SHA2_256:
124 return 16;
125 case SADB_X_AALG_SHA2_384:
126 return 24;
127 case SADB_X_AALG_SHA2_512:
128 return 32;
129 default:
130 return AH_HMAC_HASHLEN;
131 }
132 /* NOTREACHED */
133 }
134 /*
135 * NB: this is public for use by the PF_KEY support.
136 */
137 struct auth_hash *
ah_algorithm_lookup(int alg)138 ah_algorithm_lookup(int alg)
139 {
140 if (alg > SADB_AALG_MAX)
141 return NULL;
142 switch (alg) {
143 case SADB_X_AALG_NULL:
144 return &auth_hash_null;
145 case SADB_AALG_MD5HMAC:
146 return &auth_hash_hmac_md5;
147 case SADB_AALG_SHA1HMAC:
148 return &auth_hash_hmac_sha1;
149 case SADB_X_AALG_RIPEMD160HMAC:
150 return &auth_hash_hmac_ripemd_160;
151 case SADB_X_AALG_MD5:
152 return &auth_hash_key_md5;
153 case SADB_X_AALG_SHA:
154 return &auth_hash_key_sha1;
155 case SADB_X_AALG_SHA2_256:
156 return &auth_hash_hmac_sha2_256;
157 case SADB_X_AALG_SHA2_384:
158 return &auth_hash_hmac_sha2_384;
159 case SADB_X_AALG_SHA2_512:
160 return &auth_hash_hmac_sha2_512;
161 }
162 return NULL;
163 }
164
165 size_t
ah_hdrsiz(struct secasvar * sav)166 ah_hdrsiz(struct secasvar *sav)
167 {
168 size_t size;
169
170 if (sav != NULL) {
171 int authsize;
172 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
173 /*XXX not right for null algorithm--does it matter??*/
174 authsize = AUTHSIZE(sav);
175 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
176 } else {
177 /* default guess */
178 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
179 }
180 return size;
181 }
182
183 /*
184 * NB: public for use by esp_init.
185 */
186 int
ah_init0(struct secasvar * sav,struct xformsw * xsp,struct cryptoini * cria)187 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
188 {
189 struct auth_hash *thash;
190 int keylen;
191
192 thash = ah_algorithm_lookup(sav->alg_auth);
193 if (thash == NULL) {
194 DPRINTF(("%s: unsupported authentication algorithm %u\n",
195 __func__, sav->alg_auth));
196 return EINVAL;
197 }
198 /*
199 * Verify the replay state block allocation is consistent with
200 * the protocol type. We check here so we can make assumptions
201 * later during protocol processing.
202 */
203 /* NB: replay state is setup elsewhere (sigh) */
204 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
205 DPRINTF(("%s: replay state block inconsistency, "
206 "%s algorithm %s replay state\n", __func__,
207 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
208 sav->replay == NULL ? "without" : "with"));
209 return EINVAL;
210 }
211 if (sav->key_auth == NULL) {
212 DPRINTF(("%s: no authentication key for %s algorithm\n",
213 __func__, thash->name));
214 return EINVAL;
215 }
216 keylen = _KEYLEN(sav->key_auth);
217 if (keylen != thash->keysize && thash->keysize != 0) {
218 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
219 "keysize %d\n", __func__,
220 keylen, thash->name, thash->keysize));
221 return EINVAL;
222 }
223
224 sav->tdb_xform = xsp;
225 sav->tdb_authalgxform = thash;
226
227 /* Initialize crypto session. */
228 bzero(cria, sizeof (*cria));
229 cria->cri_alg = sav->tdb_authalgxform->type;
230 cria->cri_klen = _KEYBITS(sav->key_auth);
231 cria->cri_key = sav->key_auth->key_data;
232 cria->cri_mlen = AUTHSIZE(sav);
233
234 return 0;
235 }
236
237 /*
238 * ah_init() is called when an SPI is being set up.
239 */
240 static int
ah_init(struct secasvar * sav,struct xformsw * xsp)241 ah_init(struct secasvar *sav, struct xformsw *xsp)
242 {
243 struct cryptoini cria;
244 int error;
245
246 error = ah_init0(sav, xsp, &cria);
247 return error ? error :
248 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
249 }
250
251 /*
252 * Paranoia.
253 *
254 * NB: public for use by esp_zeroize (XXX).
255 */
256 int
ah_zeroize(struct secasvar * sav)257 ah_zeroize(struct secasvar *sav)
258 {
259 int err;
260
261 if (sav->key_auth)
262 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
263
264 err = crypto_freesession(sav->tdb_cryptoid);
265 sav->tdb_cryptoid = 0;
266 sav->tdb_authalgxform = NULL;
267 sav->tdb_xform = NULL;
268 return err;
269 }
270
271 /*
272 * Massage IPv4/IPv6 headers for AH processing.
273 */
274 static int
ah_massage_headers(struct mbuf ** m0,int proto,int skip,int alg,int out)275 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
276 {
277 struct mbuf *m = *m0;
278 unsigned char *ptr;
279 int off, count;
280
281 #ifdef INET
282 struct ip *ip;
283 #endif /* INET */
284
285 #ifdef INET6
286 struct ip6_ext *ip6e;
287 struct ip6_hdr ip6;
288 int alloc, len, ad;
289 #endif /* INET6 */
290
291 switch (proto) {
292 #ifdef INET
293 case AF_INET:
294 /*
295 * This is the least painful way of dealing with IPv4 header
296 * and option processing -- just make sure they're in
297 * contiguous memory.
298 */
299 *m0 = m = m_pullup(m, skip);
300 if (m == NULL) {
301 DPRINTF(("%s: m_pullup failed\n", __func__));
302 return ENOBUFS;
303 }
304
305 /* Fix the IP header */
306 ip = mtod(m, struct ip *);
307 if (V_ah_cleartos)
308 ip->ip_tos = 0;
309 ip->ip_ttl = 0;
310 ip->ip_sum = 0;
311
312 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
313 ip->ip_off &= htons(IP_DF);
314 else
315 ip->ip_off = htons(0);
316
317 ptr = mtod(m, unsigned char *) + sizeof(struct ip);
318
319 /* IPv4 option processing */
320 for (off = sizeof(struct ip); off < skip;) {
321 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
322 off + 1 < skip)
323 ;
324 else {
325 DPRINTF(("%s: illegal IPv4 option length for "
326 "option %d\n", __func__, ptr[off]));
327
328 m_freem(m);
329 return EINVAL;
330 }
331
332 switch (ptr[off]) {
333 case IPOPT_EOL:
334 off = skip; /* End the loop. */
335 break;
336
337 case IPOPT_NOP:
338 off++;
339 break;
340
341 case IPOPT_SECURITY: /* 0x82 */
342 case 0x85: /* Extended security. */
343 case 0x86: /* Commercial security. */
344 case 0x94: /* Router alert */
345 case 0x95: /* RFC1770 */
346 /* Sanity check for option length. */
347 if (ptr[off + 1] < 2) {
348 DPRINTF(("%s: illegal IPv4 option "
349 "length for option %d\n",
350 __func__, ptr[off]));
351
352 m_freem(m);
353 return EINVAL;
354 }
355
356 off += ptr[off + 1];
357 break;
358
359 case IPOPT_LSRR:
360 case IPOPT_SSRR:
361 /* Sanity check for option length. */
362 if (ptr[off + 1] < 2) {
363 DPRINTF(("%s: illegal IPv4 option "
364 "length for option %d\n",
365 __func__, ptr[off]));
366
367 m_freem(m);
368 return EINVAL;
369 }
370
371 /*
372 * On output, if we have either of the
373 * source routing options, we should
374 * swap the destination address of the
375 * IP header with the last address
376 * specified in the option, as that is
377 * what the destination's IP header
378 * will look like.
379 */
380 if (out)
381 bcopy(ptr + off + ptr[off + 1] -
382 sizeof(struct in_addr),
383 &(ip->ip_dst), sizeof(struct in_addr));
384
385 /* Fall through */
386 default:
387 /* Sanity check for option length. */
388 if (ptr[off + 1] < 2) {
389 DPRINTF(("%s: illegal IPv4 option "
390 "length for option %d\n",
391 __func__, ptr[off]));
392 m_freem(m);
393 return EINVAL;
394 }
395
396 /* Zeroize all other options. */
397 count = ptr[off + 1];
398 bcopy(ipseczeroes, ptr, count);
399 off += count;
400 break;
401 }
402
403 /* Sanity check. */
404 if (off > skip) {
405 DPRINTF(("%s: malformed IPv4 options header\n",
406 __func__));
407
408 m_freem(m);
409 return EINVAL;
410 }
411 }
412
413 break;
414 #endif /* INET */
415
416 #ifdef INET6
417 case AF_INET6: /* Ugly... */
418 /* Copy and "cook" the IPv6 header. */
419 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
420
421 /* We don't do IPv6 Jumbograms. */
422 if (ip6.ip6_plen == 0) {
423 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
424 m_freem(m);
425 return EMSGSIZE;
426 }
427
428 ip6.ip6_flow = 0;
429 ip6.ip6_hlim = 0;
430 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
431 ip6.ip6_vfc |= IPV6_VERSION;
432
433 /* Scoped address handling. */
434 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
435 ip6.ip6_src.s6_addr16[1] = 0;
436 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
437 ip6.ip6_dst.s6_addr16[1] = 0;
438
439 /* Done with IPv6 header. */
440 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
441
442 /* Let's deal with the remaining headers (if any). */
443 if (skip - sizeof(struct ip6_hdr) > 0) {
444 if (m->m_len <= skip) {
445 ptr = (unsigned char *) malloc(
446 skip - sizeof(struct ip6_hdr),
447 M_XDATA, M_NOWAIT);
448 if (ptr == NULL) {
449 DPRINTF(("%s: failed to allocate memory"
450 "for IPv6 headers\n",__func__));
451 m_freem(m);
452 return ENOBUFS;
453 }
454
455 /*
456 * Copy all the protocol headers after
457 * the IPv6 header.
458 */
459 m_copydata(m, sizeof(struct ip6_hdr),
460 skip - sizeof(struct ip6_hdr), ptr);
461 alloc = 1;
462 } else {
463 /* No need to allocate memory. */
464 ptr = mtod(m, unsigned char *) +
465 sizeof(struct ip6_hdr);
466 alloc = 0;
467 }
468 } else
469 break;
470
471 off = ip6.ip6_nxt & 0xff; /* Next header type. */
472
473 for (len = 0; len < skip - sizeof(struct ip6_hdr);)
474 switch (off) {
475 case IPPROTO_HOPOPTS:
476 case IPPROTO_DSTOPTS:
477 ip6e = (struct ip6_ext *) (ptr + len);
478
479 /*
480 * Process the mutable/immutable
481 * options -- borrows heavily from the
482 * KAME code.
483 */
484 for (count = len + sizeof(struct ip6_ext);
485 count < len + ((ip6e->ip6e_len + 1) << 3);) {
486 if (ptr[count] == IP6OPT_PAD1) {
487 count++;
488 continue; /* Skip padding. */
489 }
490
491 /* Sanity check. */
492 if (count > len +
493 ((ip6e->ip6e_len + 1) << 3)) {
494 m_freem(m);
495
496 /* Free, if we allocated. */
497 if (alloc)
498 free(ptr, M_XDATA);
499 return EINVAL;
500 }
501
502 ad = ptr[count + 1];
503
504 /* If mutable option, zeroize. */
505 if (ptr[count] & IP6OPT_MUTABLE)
506 bcopy(ipseczeroes, ptr + count,
507 ptr[count + 1]);
508
509 count += ad;
510
511 /* Sanity check. */
512 if (count >
513 skip - sizeof(struct ip6_hdr)) {
514 m_freem(m);
515
516 /* Free, if we allocated. */
517 if (alloc)
518 free(ptr, M_XDATA);
519 return EINVAL;
520 }
521 }
522
523 /* Advance. */
524 len += ((ip6e->ip6e_len + 1) << 3);
525 off = ip6e->ip6e_nxt;
526 break;
527
528 case IPPROTO_ROUTING:
529 /*
530 * Always include routing headers in
531 * computation.
532 */
533 ip6e = (struct ip6_ext *) (ptr + len);
534 len += ((ip6e->ip6e_len + 1) << 3);
535 off = ip6e->ip6e_nxt;
536 break;
537
538 default:
539 DPRINTF(("%s: unexpected IPv6 header type %d",
540 __func__, off));
541 if (alloc)
542 free(ptr, M_XDATA);
543 m_freem(m);
544 return EINVAL;
545 }
546
547 /* Copyback and free, if we allocated. */
548 if (alloc) {
549 m_copyback(m, sizeof(struct ip6_hdr),
550 skip - sizeof(struct ip6_hdr), ptr);
551 free(ptr, M_XDATA);
552 }
553
554 break;
555 #endif /* INET6 */
556 }
557
558 return 0;
559 }
560
561 /*
562 * ah_input() gets called to verify that an input packet
563 * passes authentication.
564 */
565 static int
ah_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)566 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
567 {
568 struct auth_hash *ahx;
569 struct tdb_ident *tdbi;
570 struct tdb_crypto *tc;
571 struct m_tag *mtag;
572 struct newah *ah;
573 int hl, rplen, authsize;
574
575 struct cryptodesc *crda;
576 struct cryptop *crp;
577
578 IPSEC_ASSERT(sav != NULL, ("null SA"));
579 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
580 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
581 ("null authentication xform"));
582
583 /* Figure out header size. */
584 rplen = HDRSIZE(sav);
585
586 /* XXX don't pullup, just copy header */
587 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
588 if (ah == NULL) {
589 DPRINTF(("ah_input: cannot pullup header\n"));
590 AHSTAT_INC(ahs_hdrops); /*XXX*/
591 m_freem(m);
592 return ENOBUFS;
593 }
594
595 /* Check replay window, if applicable. */
596 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
597 AHSTAT_INC(ahs_replay);
598 DPRINTF(("%s: packet replay failure: %s\n", __func__,
599 ipsec_logsastr(sav)));
600 m_freem(m);
601 return ENOBUFS;
602 }
603
604 /* Verify AH header length. */
605 hl = ah->ah_len * sizeof (u_int32_t);
606 ahx = sav->tdb_authalgxform;
607 authsize = AUTHSIZE(sav);
608 if (hl != authsize + rplen - sizeof (struct ah)) {
609 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
610 " for packet in SA %s/%08lx\n", __func__,
611 hl, (u_long) (authsize + rplen - sizeof (struct ah)),
612 ipsec_address(&sav->sah->saidx.dst),
613 (u_long) ntohl(sav->spi)));
614 AHSTAT_INC(ahs_badauthl);
615 m_freem(m);
616 return EACCES;
617 }
618 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
619
620 /* Get crypto descriptors. */
621 crp = crypto_getreq(1);
622 if (crp == NULL) {
623 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
624 AHSTAT_INC(ahs_crypto);
625 m_freem(m);
626 return ENOBUFS;
627 }
628
629 crda = crp->crp_desc;
630 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
631
632 crda->crd_skip = 0;
633 crda->crd_len = m->m_pkthdr.len;
634 crda->crd_inject = skip + rplen;
635
636 /* Authentication operation. */
637 crda->crd_alg = ahx->type;
638 crda->crd_klen = _KEYBITS(sav->key_auth);
639 crda->crd_key = sav->key_auth->key_data;
640
641 /* Find out if we've already done crypto. */
642 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
643 mtag != NULL;
644 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
645 tdbi = (struct tdb_ident *) (mtag + 1);
646 if (tdbi->proto == sav->sah->saidx.proto &&
647 tdbi->spi == sav->spi &&
648 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
649 sizeof (union sockaddr_union)))
650 break;
651 }
652
653 /* Allocate IPsec-specific opaque crypto info. */
654 if (mtag == NULL) {
655 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
656 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
657 } else {
658 /* Hash verification has already been done successfully. */
659 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
660 M_XDATA, M_NOWAIT|M_ZERO);
661 }
662 if (tc == NULL) {
663 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
664 AHSTAT_INC(ahs_crypto);
665 crypto_freereq(crp);
666 m_freem(m);
667 return ENOBUFS;
668 }
669
670 /* Only save information if crypto processing is needed. */
671 if (mtag == NULL) {
672 int error;
673
674 /*
675 * Save the authenticator, the skipped portion of the packet,
676 * and the AH header.
677 */
678 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
679
680 /* Zeroize the authenticator on the packet. */
681 m_copyback(m, skip + rplen, authsize, ipseczeroes);
682
683 /* "Massage" the packet headers for crypto processing. */
684 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
685 skip, ahx->type, 0);
686 if (error != 0) {
687 /* NB: mbuf is free'd by ah_massage_headers */
688 AHSTAT_INC(ahs_hdrops);
689 free(tc, M_XDATA);
690 crypto_freereq(crp);
691 return error;
692 }
693 }
694
695 /* Crypto operation descriptor. */
696 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
697 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
698 crp->crp_buf = (caddr_t) m;
699 crp->crp_callback = ah_input_cb;
700 crp->crp_sid = sav->tdb_cryptoid;
701 crp->crp_opaque = (caddr_t) tc;
702
703 /* These are passed as-is to the callback. */
704 tc->tc_spi = sav->spi;
705 tc->tc_dst = sav->sah->saidx.dst;
706 tc->tc_proto = sav->sah->saidx.proto;
707 tc->tc_nxt = ah->ah_nxt;
708 tc->tc_protoff = protoff;
709 tc->tc_skip = skip;
710 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
711 KEY_ADDREFSA(sav);
712 tc->tc_sav = sav;
713
714 if (mtag == NULL)
715 return crypto_dispatch(crp);
716 else
717 return ah_input_cb(crp);
718 }
719
720 /*
721 * AH input callback from the crypto driver.
722 */
723 static int
ah_input_cb(struct cryptop * crp)724 ah_input_cb(struct cryptop *crp)
725 {
726 int rplen, error, skip, protoff;
727 unsigned char calc[AH_ALEN_MAX];
728 struct mbuf *m;
729 struct cryptodesc *crd;
730 struct auth_hash *ahx;
731 struct tdb_crypto *tc;
732 struct m_tag *mtag;
733 struct secasvar *sav;
734 struct secasindex *saidx;
735 u_int8_t nxt;
736 caddr_t ptr;
737 int authsize;
738
739 crd = crp->crp_desc;
740
741 tc = (struct tdb_crypto *) crp->crp_opaque;
742 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
743 skip = tc->tc_skip;
744 nxt = tc->tc_nxt;
745 protoff = tc->tc_protoff;
746 mtag = (struct m_tag *) tc->tc_ptr;
747 m = (struct mbuf *) crp->crp_buf;
748
749 sav = tc->tc_sav;
750 IPSEC_ASSERT(sav != NULL, ("null SA!"));
751
752 saidx = &sav->sah->saidx;
753 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
754 saidx->dst.sa.sa_family == AF_INET6,
755 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
756
757 ahx = (struct auth_hash *) sav->tdb_authalgxform;
758
759 /* Check for crypto errors. */
760 if (crp->crp_etype) {
761 if (sav->tdb_cryptoid != 0)
762 sav->tdb_cryptoid = crp->crp_sid;
763
764 if (crp->crp_etype == EAGAIN)
765 return (crypto_dispatch(crp));
766
767 AHSTAT_INC(ahs_noxform);
768 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
769 error = crp->crp_etype;
770 goto bad;
771 } else {
772 AHSTAT_INC(ahs_hist[sav->alg_auth]);
773 crypto_freereq(crp); /* No longer needed. */
774 crp = NULL;
775 }
776
777 /* Shouldn't happen... */
778 if (m == NULL) {
779 AHSTAT_INC(ahs_crypto);
780 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
781 error = EINVAL;
782 goto bad;
783 }
784
785 /* Figure out header size. */
786 rplen = HDRSIZE(sav);
787 authsize = AUTHSIZE(sav);
788
789 /* Copy authenticator off the packet. */
790 m_copydata(m, skip + rplen, authsize, calc);
791
792 /*
793 * If we have an mtag, we don't need to verify the authenticator --
794 * it has been verified by an IPsec-aware NIC.
795 */
796 if (mtag == NULL) {
797 ptr = (caddr_t) (tc + 1);
798
799 /* Verify authenticator. */
800 if (bcmp(ptr + skip + rplen, calc, authsize)) {
801 DPRINTF(("%s: authentication hash mismatch for packet "
802 "in SA %s/%08lx\n", __func__,
803 ipsec_address(&saidx->dst),
804 (u_long) ntohl(sav->spi)));
805 AHSTAT_INC(ahs_badauth);
806 error = EACCES;
807 goto bad;
808 }
809
810 /* Fix the Next Protocol field. */
811 ((u_int8_t *) ptr)[protoff] = nxt;
812
813 /* Copyback the saved (uncooked) network headers. */
814 m_copyback(m, 0, skip, ptr);
815 } else {
816 /* Fix the Next Protocol field. */
817 m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
818 }
819
820 free(tc, M_XDATA), tc = NULL; /* No longer needed */
821
822 /*
823 * Header is now authenticated.
824 */
825 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
826
827 /*
828 * Update replay sequence number, if appropriate.
829 */
830 if (sav->replay) {
831 u_int32_t seq;
832
833 m_copydata(m, skip + offsetof(struct newah, ah_seq),
834 sizeof (seq), (caddr_t) &seq);
835 if (ipsec_updatereplay(ntohl(seq), sav)) {
836 AHSTAT_INC(ahs_replay);
837 error = ENOBUFS; /*XXX as above*/
838 goto bad;
839 }
840 }
841
842 /*
843 * Remove the AH header and authenticator from the mbuf.
844 */
845 error = m_striphdr(m, skip, rplen + authsize);
846 if (error) {
847 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
848 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
849
850 AHSTAT_INC(ahs_hdrops);
851 goto bad;
852 }
853
854 switch (saidx->dst.sa.sa_family) {
855 #ifdef INET6
856 case AF_INET6:
857 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag);
858 break;
859 #endif
860 #ifdef INET
861 case AF_INET:
862 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag);
863 break;
864 #endif
865 default:
866 panic("%s: Unexpected address family: %d saidx=%p", __func__,
867 saidx->dst.sa.sa_family, saidx);
868 }
869
870 KEY_FREESAV(&sav);
871 return error;
872 bad:
873 if (sav)
874 KEY_FREESAV(&sav);
875 if (m != NULL)
876 m_freem(m);
877 if (tc != NULL)
878 free(tc, M_XDATA);
879 if (crp != NULL)
880 crypto_freereq(crp);
881 return error;
882 }
883
884 /*
885 * AH output routine, called by ipsec[46]_process_packet().
886 */
887 static int
ah_output(struct mbuf * m,struct ipsecrequest * isr,struct mbuf ** mp,int skip,int protoff)888 ah_output(
889 struct mbuf *m,
890 struct ipsecrequest *isr,
891 struct mbuf **mp,
892 int skip,
893 int protoff)
894 {
895 struct secasvar *sav;
896 struct auth_hash *ahx;
897 struct cryptodesc *crda;
898 struct tdb_crypto *tc;
899 struct mbuf *mi;
900 struct cryptop *crp;
901 u_int16_t iplen;
902 int error, rplen, authsize, maxpacketsize, roff;
903 u_int8_t prot;
904 struct newah *ah;
905
906 sav = isr->sav;
907 IPSEC_ASSERT(sav != NULL, ("null SA"));
908 ahx = sav->tdb_authalgxform;
909 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
910
911 AHSTAT_INC(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(("%s: unknown/unsupported protocol family %u, "
930 "SA %s/%08lx\n", __func__,
931 sav->sah->saidx.dst.sa.sa_family,
932 ipsec_address(&sav->sah->saidx.dst),
933 (u_long) ntohl(sav->spi)));
934 AHSTAT_INC(ahs_nopf);
935 error = EPFNOSUPPORT;
936 goto bad;
937 }
938 authsize = AUTHSIZE(sav);
939 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
940 DPRINTF(("%s: packet in SA %s/%08lx got too big "
941 "(len %u, max len %u)\n", __func__,
942 ipsec_address(&sav->sah->saidx.dst),
943 (u_long) ntohl(sav->spi),
944 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
945 AHSTAT_INC(ahs_toobig);
946 error = EMSGSIZE;
947 goto bad;
948 }
949
950 /* Update the counters. */
951 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
952
953 m = m_unshare(m, M_NOWAIT);
954 if (m == NULL) {
955 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
956 ipsec_address(&sav->sah->saidx.dst),
957 (u_long) ntohl(sav->spi)));
958 AHSTAT_INC(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(("%s: failed to inject %u byte AH header for SA "
967 "%s/%08lx\n", __func__,
968 rplen + authsize,
969 ipsec_address(&sav->sah->saidx.dst),
970 (u_long) ntohl(sav->spi)));
971 AHSTAT_INC(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(("%s: replay counter wrapped for SA %s/%08lx\n",
996 __func__,
997 ipsec_address(&sav->sah->saidx.dst),
998 (u_long) ntohl(sav->spi)));
999 AHSTAT_INC(ahs_wrap);
1000 error = EINVAL;
1001 goto bad;
1002 }
1003 #ifdef REGRESSION
1004 /* Emulate replay attack when ipsec_replay is TRUE. */
1005 if (!V_ipsec_replay)
1006 #endif
1007 sav->replay->count++;
1008 ah->ah_seq = htonl(sav->replay->count);
1009 }
1010
1011 /* Get crypto descriptors. */
1012 crp = crypto_getreq(1);
1013 if (crp == NULL) {
1014 DPRINTF(("%s: failed to acquire crypto descriptors\n",
1015 __func__));
1016 AHSTAT_INC(ahs_crypto);
1017 error = ENOBUFS;
1018 goto bad;
1019 }
1020
1021 crda = crp->crp_desc;
1022
1023 crda->crd_skip = 0;
1024 crda->crd_inject = skip + rplen;
1025 crda->crd_len = m->m_pkthdr.len;
1026
1027 /* Authentication operation. */
1028 crda->crd_alg = ahx->type;
1029 crda->crd_key = sav->key_auth->key_data;
1030 crda->crd_klen = _KEYBITS(sav->key_auth);
1031
1032 /* Allocate IPsec-specific opaque crypto info. */
1033 tc = (struct tdb_crypto *) malloc(
1034 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1035 if (tc == NULL) {
1036 crypto_freereq(crp);
1037 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
1038 AHSTAT_INC(ahs_crypto);
1039 error = ENOBUFS;
1040 goto bad;
1041 }
1042
1043 /* Save the skipped portion of the packet. */
1044 m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1045
1046 /*
1047 * Fix IP header length on the header used for
1048 * authentication. We don't need to fix the original
1049 * header length as it will be fixed by our caller.
1050 */
1051 switch (sav->sah->saidx.dst.sa.sa_family) {
1052 #ifdef INET
1053 case AF_INET:
1054 bcopy(((caddr_t)(tc + 1)) +
1055 offsetof(struct ip, ip_len),
1056 (caddr_t) &iplen, sizeof(u_int16_t));
1057 iplen = htons(ntohs(iplen) + rplen + authsize);
1058 m_copyback(m, offsetof(struct ip, ip_len),
1059 sizeof(u_int16_t), (caddr_t) &iplen);
1060 break;
1061 #endif /* INET */
1062
1063 #ifdef INET6
1064 case AF_INET6:
1065 bcopy(((caddr_t)(tc + 1)) +
1066 offsetof(struct ip6_hdr, ip6_plen),
1067 (caddr_t) &iplen, sizeof(u_int16_t));
1068 iplen = htons(ntohs(iplen) + rplen + authsize);
1069 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1070 sizeof(u_int16_t), (caddr_t) &iplen);
1071 break;
1072 #endif /* INET6 */
1073 }
1074
1075 /* Fix the Next Header field in saved header. */
1076 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1077
1078 /* Update the Next Protocol field in the IP header. */
1079 prot = IPPROTO_AH;
1080 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1081
1082 /* "Massage" the packet headers for crypto processing. */
1083 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1084 skip, ahx->type, 1);
1085 if (error != 0) {
1086 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1087 free(tc, M_XDATA);
1088 crypto_freereq(crp);
1089 goto bad;
1090 }
1091
1092 /* Crypto operation descriptor. */
1093 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1094 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1095 crp->crp_buf = (caddr_t) m;
1096 crp->crp_callback = ah_output_cb;
1097 crp->crp_sid = sav->tdb_cryptoid;
1098 crp->crp_opaque = (caddr_t) tc;
1099
1100 /* These are passed as-is to the callback. */
1101 tc->tc_isr = isr;
1102 KEY_ADDREFSA(sav);
1103 tc->tc_sav = sav;
1104 tc->tc_spi = sav->spi;
1105 tc->tc_dst = sav->sah->saidx.dst;
1106 tc->tc_proto = sav->sah->saidx.proto;
1107 tc->tc_skip = skip;
1108 tc->tc_protoff = protoff;
1109
1110 return crypto_dispatch(crp);
1111 bad:
1112 if (m)
1113 m_freem(m);
1114 return (error);
1115 }
1116
1117 /*
1118 * AH output callback from the crypto driver.
1119 */
1120 static int
ah_output_cb(struct cryptop * crp)1121 ah_output_cb(struct cryptop *crp)
1122 {
1123 int skip, protoff, error;
1124 struct tdb_crypto *tc;
1125 struct ipsecrequest *isr;
1126 struct secasvar *sav;
1127 struct mbuf *m;
1128 caddr_t ptr;
1129
1130 tc = (struct tdb_crypto *) crp->crp_opaque;
1131 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
1132 skip = tc->tc_skip;
1133 protoff = tc->tc_protoff;
1134 ptr = (caddr_t) (tc + 1);
1135 m = (struct mbuf *) crp->crp_buf;
1136
1137 isr = tc->tc_isr;
1138 IPSECREQUEST_LOCK(isr);
1139 sav = tc->tc_sav;
1140 /* With the isr lock released SA pointer can be updated. */
1141 if (sav != isr->sav) {
1142 AHSTAT_INC(ahs_notdb);
1143 DPRINTF(("%s: SA expired while in crypto\n", __func__));
1144 error = ENOBUFS; /*XXX*/
1145 goto bad;
1146 }
1147
1148 /* Check for crypto errors. */
1149 if (crp->crp_etype) {
1150 if (sav->tdb_cryptoid != 0)
1151 sav->tdb_cryptoid = crp->crp_sid;
1152
1153 if (crp->crp_etype == EAGAIN) {
1154 IPSECREQUEST_UNLOCK(isr);
1155 return (crypto_dispatch(crp));
1156 }
1157
1158 AHSTAT_INC(ahs_noxform);
1159 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1160 error = crp->crp_etype;
1161 goto bad;
1162 }
1163
1164 /* Shouldn't happen... */
1165 if (m == NULL) {
1166 AHSTAT_INC(ahs_crypto);
1167 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1168 error = EINVAL;
1169 goto bad;
1170 }
1171 AHSTAT_INC(ahs_hist[sav->alg_auth]);
1172
1173 /*
1174 * Copy original headers (with the new protocol number) back
1175 * in place.
1176 */
1177 m_copyback(m, 0, skip, ptr);
1178
1179 /* No longer needed. */
1180 free(tc, M_XDATA);
1181 crypto_freereq(crp);
1182
1183 #ifdef REGRESSION
1184 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1185 if (V_ipsec_integrity) {
1186 int alen;
1187
1188 /*
1189 * Corrupt HMAC if we want to test integrity verification of
1190 * the other side.
1191 */
1192 alen = AUTHSIZE(sav);
1193 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1194 }
1195 #endif
1196
1197 /* NB: m is reclaimed by ipsec_process_done. */
1198 error = ipsec_process_done(m, isr);
1199 KEY_FREESAV(&sav);
1200 IPSECREQUEST_UNLOCK(isr);
1201 return error;
1202 bad:
1203 if (sav)
1204 KEY_FREESAV(&sav);
1205 IPSECREQUEST_UNLOCK(isr);
1206 if (m)
1207 m_freem(m);
1208 free(tc, M_XDATA);
1209 crypto_freereq(crp);
1210 return error;
1211 }
1212
1213 static struct xformsw ah_xformsw = {
1214 XF_AH, XFT_AUTH, "IPsec AH",
1215 ah_init, ah_zeroize, ah_input, ah_output,
1216 };
1217
1218 static void
ah_attach(void)1219 ah_attach(void)
1220 {
1221
1222 xform_register(&ah_xformsw);
1223 }
1224
1225 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
1226