1 /* $FreeBSD: releng/11.0/sys/netipsec/xform_ah.c 288418 2015-09-30 08:16:33Z ae $ */
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/lock.h>
49 #include <sys/rwlock.h>
50 #include <sys/sysctl.h>
51
52 #include <net/if.h>
53 #include <net/vnet.h>
54
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/ip_ecn.h>
59 #include <netinet/ip6.h>
60
61 #include <netipsec/ipsec.h>
62 #include <netipsec/ah.h>
63 #include <netipsec/ah_var.h>
64 #include <netipsec/xform.h>
65
66 #ifdef INET6
67 #include <netinet6/ip6_var.h>
68 #include <netipsec/ipsec6.h>
69 #include <netinet6/ip6_ecn.h>
70 #endif
71
72 #include <netipsec/key.h>
73 #include <netipsec/key_debug.h>
74
75 #include <opencrypto/cryptodev.h>
76
77 /*
78 * Return header size in bytes. The old protocol did not support
79 * the replay counter; the new protocol always includes the counter.
80 */
81 #define HDRSIZE(sav) \
82 (((sav)->flags & SADB_X_EXT_OLD) ? \
83 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
84 /*
85 * Return authenticator size in bytes, based on a field in the
86 * algorithm descriptor.
87 */
88 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \
89 xform_ah_authsize((sav)->tdb_authalgxform))
90
91 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
92 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
93 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat);
94 VNET_PCPUSTAT_SYSINIT(ahstat);
95
96 #ifdef VIMAGE
97 VNET_PCPUSTAT_SYSUNINIT(ahstat);
98 #endif /* VIMAGE */
99
100 #ifdef INET
101 SYSCTL_DECL(_net_inet_ah);
102 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable,
103 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
104 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos,
105 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
106 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat,
107 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)");
108 #endif
109
110 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
111
112 static int ah_input_cb(struct cryptop*);
113 static int ah_output_cb(struct cryptop*);
114
115 int
116 xform_ah_authsize(struct auth_hash *esph)
117 {
118 int alen;
119
120 if (esph == NULL)
121 return 0;
122
123 switch (esph->type) {
124 case CRYPTO_SHA2_256_HMAC:
125 case CRYPTO_SHA2_384_HMAC:
126 case CRYPTO_SHA2_512_HMAC:
127 alen = esph->hashsize / 2; /* RFC4868 2.3 */
128 break;
129
130 case CRYPTO_AES_128_NIST_GMAC:
131 case CRYPTO_AES_192_NIST_GMAC:
132 case CRYPTO_AES_256_NIST_GMAC:
133 alen = esph->hashsize;
134 break;
135
136 default:
137 alen = AH_HMAC_HASHLEN;
138 break;
139 }
140
141 return alen;
142 }
143
144 /*
145 * NB: this is public for use by the PF_KEY support.
146 */
147 struct auth_hash *
148 ah_algorithm_lookup(int alg)
149 {
150 if (alg > SADB_AALG_MAX)
151 return NULL;
152 switch (alg) {
153 case SADB_X_AALG_NULL:
154 return &auth_hash_null;
155 case SADB_AALG_MD5HMAC:
156 return &auth_hash_hmac_md5;
157 case SADB_AALG_SHA1HMAC:
158 return &auth_hash_hmac_sha1;
159 case SADB_X_AALG_RIPEMD160HMAC:
160 return &auth_hash_hmac_ripemd_160;
161 case SADB_X_AALG_MD5:
162 return &auth_hash_key_md5;
163 case SADB_X_AALG_SHA:
164 return &auth_hash_key_sha1;
165 case SADB_X_AALG_SHA2_256:
166 return &auth_hash_hmac_sha2_256;
167 case SADB_X_AALG_SHA2_384:
168 return &auth_hash_hmac_sha2_384;
169 case SADB_X_AALG_SHA2_512:
170 return &auth_hash_hmac_sha2_512;
171 case SADB_X_AALG_AES128GMAC:
172 return &auth_hash_nist_gmac_aes_128;
173 case SADB_X_AALG_AES192GMAC:
174 return &auth_hash_nist_gmac_aes_192;
175 case SADB_X_AALG_AES256GMAC:
176 return &auth_hash_nist_gmac_aes_256;
177 }
178 return NULL;
179 }
180
181 size_t
182 ah_hdrsiz(struct secasvar *sav)
183 {
184 size_t size;
185
186 if (sav != NULL) {
187 int authsize;
188 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
189 /*XXX not right for null algorithm--does it matter??*/
190 authsize = AUTHSIZE(sav);
191 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
192 } else {
193 /* default guess */
194 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
195 }
196 return size;
197 }
198
199 /*
200 * NB: public for use by esp_init.
201 */
202 int
203 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
204 {
205 struct auth_hash *thash;
206 int keylen;
207
208 thash = ah_algorithm_lookup(sav->alg_auth);
209 if (thash == NULL) {
210 DPRINTF(("%s: unsupported authentication algorithm %u\n",
211 __func__, sav->alg_auth));
212 return EINVAL;
213 }
214 /*
215 * Verify the replay state block allocation is consistent with
216 * the protocol type. We check here so we can make assumptions
217 * later during protocol processing.
218 */
219 /* NB: replay state is setup elsewhere (sigh) */
220 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
221 DPRINTF(("%s: replay state block inconsistency, "
222 "%s algorithm %s replay state\n", __func__,
223 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
224 sav->replay == NULL ? "without" : "with"));
225 return EINVAL;
226 }
227 if (sav->key_auth == NULL) {
228 DPRINTF(("%s: no authentication key for %s algorithm\n",
229 __func__, thash->name));
230 return EINVAL;
231 }
232 keylen = _KEYLEN(sav->key_auth);
233 if (keylen != thash->keysize && thash->keysize != 0) {
234 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
235 "keysize %d\n", __func__,
236 keylen, thash->name, thash->keysize));
237 return EINVAL;
238 }
239
240 sav->tdb_xform = xsp;
241 sav->tdb_authalgxform = thash;
242
243 /* Initialize crypto session. */
244 bzero(cria, sizeof (*cria));
245 cria->cri_alg = sav->tdb_authalgxform->type;
246 cria->cri_klen = _KEYBITS(sav->key_auth);
247 cria->cri_key = sav->key_auth->key_data;
248 cria->cri_mlen = AUTHSIZE(sav);
249
250 return 0;
251 }
252
253 /*
254 * ah_init() is called when an SPI is being set up.
255 */
256 static int
257 ah_init(struct secasvar *sav, struct xformsw *xsp)
258 {
259 struct cryptoini cria;
260 int error;
261
262 error = ah_init0(sav, xsp, &cria);
263 return error ? error :
264 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
265 }
266
267 /*
268 * Paranoia.
269 *
270 * NB: public for use by esp_zeroize (XXX).
271 */
272 int
273 ah_zeroize(struct secasvar *sav)
274 {
275 int err;
276
277 if (sav->key_auth)
278 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
279
280 err = crypto_freesession(sav->tdb_cryptoid);
281 sav->tdb_cryptoid = 0;
282 sav->tdb_authalgxform = NULL;
283 sav->tdb_xform = NULL;
284 return err;
285 }
286
287 /*
288 * Massage IPv4/IPv6 headers for AH processing.
289 */
290 static int
291 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
292 {
293 struct mbuf *m = *m0;
294 unsigned char *ptr;
295 int off, count;
296
297 #ifdef INET
298 struct ip *ip;
299 #endif /* INET */
300
301 #ifdef INET6
302 struct ip6_ext *ip6e;
303 struct ip6_hdr ip6;
304 int alloc, len, ad;
305 #endif /* INET6 */
306
307 switch (proto) {
308 #ifdef INET
309 case AF_INET:
310 /*
311 * This is the least painful way of dealing with IPv4 header
312 * and option processing -- just make sure they're in
313 * contiguous memory.
314 */
315 *m0 = m = m_pullup(m, skip);
316 if (m == NULL) {
317 DPRINTF(("%s: m_pullup failed\n", __func__));
318 return ENOBUFS;
319 }
320
321 /* Fix the IP header */
322 ip = mtod(m, struct ip *);
323 if (V_ah_cleartos)
324 ip->ip_tos = 0;
325 ip->ip_ttl = 0;
326 ip->ip_sum = 0;
327
328 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
329 ip->ip_off &= htons(IP_DF);
330 else
331 ip->ip_off = htons(0);
332
333 ptr = mtod(m, unsigned char *) + sizeof(struct ip);
334
335 /* IPv4 option processing */
336 for (off = sizeof(struct ip); off < skip;) {
337 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
338 off + 1 < skip)
339 ;
340 else {
341 DPRINTF(("%s: illegal IPv4 option length for "
342 "option %d\n", __func__, ptr[off]));
343
344 m_freem(m);
345 return EINVAL;
346 }
347
348 switch (ptr[off]) {
349 case IPOPT_EOL:
350 off = skip; /* End the loop. */
351 break;
352
353 case IPOPT_NOP:
354 off++;
355 break;
356
357 case IPOPT_SECURITY: /* 0x82 */
358 case 0x85: /* Extended security. */
359 case 0x86: /* Commercial security. */
360 case 0x94: /* Router alert */
361 case 0x95: /* RFC1770 */
362 /* Sanity check for option length. */
363 if (ptr[off + 1] < 2) {
364 DPRINTF(("%s: illegal IPv4 option "
365 "length for option %d\n",
366 __func__, ptr[off]));
367
368 m_freem(m);
369 return EINVAL;
370 }
371
372 off += ptr[off + 1];
373 break;
374
375 case IPOPT_LSRR:
376 case IPOPT_SSRR:
377 /* Sanity check for option length. */
378 if (ptr[off + 1] < 2) {
379 DPRINTF(("%s: illegal IPv4 option "
380 "length for option %d\n",
381 __func__, ptr[off]));
382
383 m_freem(m);
384 return EINVAL;
385 }
386
387 /*
388 * On output, if we have either of the
389 * source routing options, we should
390 * swap the destination address of the
391 * IP header with the last address
392 * specified in the option, as that is
393 * what the destination's IP header
394 * will look like.
395 */
396 if (out)
397 bcopy(ptr + off + ptr[off + 1] -
398 sizeof(struct in_addr),
399 &(ip->ip_dst), sizeof(struct in_addr));
400
401 /* Fall through */
402 default:
403 /* Sanity check for option length. */
404 if (ptr[off + 1] < 2) {
405 DPRINTF(("%s: illegal IPv4 option "
406 "length for option %d\n",
407 __func__, ptr[off]));
408 m_freem(m);
409 return EINVAL;
410 }
411
412 /* Zeroize all other options. */
413 count = ptr[off + 1];
414 bcopy(ipseczeroes, ptr, count);
415 off += count;
416 break;
417 }
418
419 /* Sanity check. */
420 if (off > skip) {
421 DPRINTF(("%s: malformed IPv4 options header\n",
422 __func__));
423
424 m_freem(m);
425 return EINVAL;
426 }
427 }
428
429 break;
430 #endif /* INET */
431
432 #ifdef INET6
433 case AF_INET6: /* Ugly... */
434 /* Copy and "cook" the IPv6 header. */
435 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
436
437 /* We don't do IPv6 Jumbograms. */
438 if (ip6.ip6_plen == 0) {
439 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
440 m_freem(m);
441 return EMSGSIZE;
442 }
443
444 ip6.ip6_flow = 0;
445 ip6.ip6_hlim = 0;
446 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
447 ip6.ip6_vfc |= IPV6_VERSION;
448
449 /* Scoped address handling. */
450 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
451 ip6.ip6_src.s6_addr16[1] = 0;
452 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
453 ip6.ip6_dst.s6_addr16[1] = 0;
454
455 /* Done with IPv6 header. */
456 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
457
458 /* Let's deal with the remaining headers (if any). */
459 if (skip - sizeof(struct ip6_hdr) > 0) {
460 if (m->m_len <= skip) {
461 ptr = (unsigned char *) malloc(
462 skip - sizeof(struct ip6_hdr),
463 M_XDATA, M_NOWAIT);
464 if (ptr == NULL) {
465 DPRINTF(("%s: failed to allocate memory"
466 "for IPv6 headers\n",__func__));
467 m_freem(m);
468 return ENOBUFS;
469 }
470
471 /*
472 * Copy all the protocol headers after
473 * the IPv6 header.
474 */
475 m_copydata(m, sizeof(struct ip6_hdr),
476 skip - sizeof(struct ip6_hdr), ptr);
477 alloc = 1;
478 } else {
479 /* No need to allocate memory. */
480 ptr = mtod(m, unsigned char *) +
481 sizeof(struct ip6_hdr);
482 alloc = 0;
483 }
484 } else
485 break;
486
487 off = ip6.ip6_nxt & 0xff; /* Next header type. */
488
489 for (len = 0; len < skip - sizeof(struct ip6_hdr);)
490 switch (off) {
491 case IPPROTO_HOPOPTS:
492 case IPPROTO_DSTOPTS:
493 ip6e = (struct ip6_ext *) (ptr + len);
494
495 /*
496 * Process the mutable/immutable
497 * options -- borrows heavily from the
498 * KAME code.
499 */
500 for (count = len + sizeof(struct ip6_ext);
501 count < len + ((ip6e->ip6e_len + 1) << 3);) {
502 if (ptr[count] == IP6OPT_PAD1) {
503 count++;
504 continue; /* Skip padding. */
505 }
506
507 /* Sanity check. */
508 if (count > len +
509 ((ip6e->ip6e_len + 1) << 3)) {
510 m_freem(m);
511
512 /* Free, if we allocated. */
513 if (alloc)
514 free(ptr, M_XDATA);
515 return EINVAL;
516 }
517
518 ad = ptr[count + 1];
519
520 /* If mutable option, zeroize. */
521 if (ptr[count] & IP6OPT_MUTABLE)
522 bcopy(ipseczeroes, ptr + count,
523 ptr[count + 1]);
524
525 count += ad;
526
527 /* Sanity check. */
528 if (count >
529 skip - sizeof(struct ip6_hdr)) {
530 m_freem(m);
531
532 /* Free, if we allocated. */
533 if (alloc)
534 free(ptr, M_XDATA);
535 return EINVAL;
536 }
537 }
538
539 /* Advance. */
540 len += ((ip6e->ip6e_len + 1) << 3);
541 off = ip6e->ip6e_nxt;
542 break;
543
544 case IPPROTO_ROUTING:
545 /*
546 * Always include routing headers in
547 * computation.
548 */
549 ip6e = (struct ip6_ext *) (ptr + len);
550 len += ((ip6e->ip6e_len + 1) << 3);
551 off = ip6e->ip6e_nxt;
552 break;
553
554 default:
555 DPRINTF(("%s: unexpected IPv6 header type %d",
556 __func__, off));
557 if (alloc)
558 free(ptr, M_XDATA);
559 m_freem(m);
560 return EINVAL;
561 }
562
563 /* Copyback and free, if we allocated. */
564 if (alloc) {
565 m_copyback(m, sizeof(struct ip6_hdr),
566 skip - sizeof(struct ip6_hdr), ptr);
567 free(ptr, M_XDATA);
568 }
569
570 break;
571 #endif /* INET6 */
572 }
573
574 return 0;
575 }
576
577 /*
578 * ah_input() gets called to verify that an input packet
579 * passes authentication.
580 */
581 static int
582 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
583 {
584 char buf[128];
585 struct auth_hash *ahx;
586 struct tdb_crypto *tc;
587 struct newah *ah;
588 int hl, rplen, authsize, error;
589
590 struct cryptodesc *crda;
591 struct cryptop *crp;
592
593 IPSEC_ASSERT(sav != NULL, ("null SA"));
594 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
595 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
596 ("null authentication xform"));
597
598 /* Figure out header size. */
599 rplen = HDRSIZE(sav);
600
601 /* XXX don't pullup, just copy header */
602 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
603 if (ah == NULL) {
604 DPRINTF(("ah_input: cannot pullup header\n"));
605 AHSTAT_INC(ahs_hdrops); /*XXX*/
606 m_freem(m);
607 return ENOBUFS;
608 }
609
610 /* Check replay window, if applicable. */
611 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
612 AHSTAT_INC(ahs_replay);
613 DPRINTF(("%s: packet replay failure: %s\n", __func__,
614 ipsec_logsastr(sav, buf, sizeof(buf))));
615 m_freem(m);
616 return ENOBUFS;
617 }
618
619 /* Verify AH header length. */
620 hl = ah->ah_len * sizeof (u_int32_t);
621 ahx = sav->tdb_authalgxform;
622 authsize = AUTHSIZE(sav);
623 if (hl != authsize + rplen - sizeof (struct ah)) {
624 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
625 " for packet in SA %s/%08lx\n", __func__, hl,
626 (u_long) (authsize + rplen - sizeof (struct ah)),
627 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
628 (u_long) ntohl(sav->spi)));
629 AHSTAT_INC(ahs_badauthl);
630 m_freem(m);
631 return EACCES;
632 }
633 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
634
635 /* Get crypto descriptors. */
636 crp = crypto_getreq(1);
637 if (crp == NULL) {
638 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
639 AHSTAT_INC(ahs_crypto);
640 m_freem(m);
641 return ENOBUFS;
642 }
643
644 crda = crp->crp_desc;
645 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
646
647 crda->crd_skip = 0;
648 crda->crd_len = m->m_pkthdr.len;
649 crda->crd_inject = skip + rplen;
650
651 /* Authentication operation. */
652 crda->crd_alg = ahx->type;
653 crda->crd_klen = _KEYBITS(sav->key_auth);
654 crda->crd_key = sav->key_auth->key_data;
655
656 /* Allocate IPsec-specific opaque crypto info. */
657 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
658 skip + rplen + authsize, M_XDATA, M_NOWAIT | M_ZERO);
659 if (tc == NULL) {
660 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
661 AHSTAT_INC(ahs_crypto);
662 crypto_freereq(crp);
663 m_freem(m);
664 return ENOBUFS;
665 }
666
667 /*
668 * Save the authenticator, the skipped portion of the packet,
669 * and the AH header.
670 */
671 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
672
673 /* Zeroize the authenticator on the packet. */
674 m_copyback(m, skip + rplen, authsize, ipseczeroes);
675
676 /* "Massage" the packet headers for crypto processing. */
677 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
678 skip, ahx->type, 0);
679 if (error != 0) {
680 /* NB: mbuf is free'd by ah_massage_headers */
681 AHSTAT_INC(ahs_hdrops);
682 free(tc, M_XDATA);
683 crypto_freereq(crp);
684 return (error);
685 }
686
687 /* Crypto operation descriptor. */
688 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
689 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
690 crp->crp_buf = (caddr_t) m;
691 crp->crp_callback = ah_input_cb;
692 crp->crp_sid = sav->tdb_cryptoid;
693 crp->crp_opaque = (caddr_t) tc;
694
695 /* These are passed as-is to the callback. */
696 tc->tc_spi = sav->spi;
697 tc->tc_dst = sav->sah->saidx.dst;
698 tc->tc_proto = sav->sah->saidx.proto;
699 tc->tc_nxt = ah->ah_nxt;
700 tc->tc_protoff = protoff;
701 tc->tc_skip = skip;
702 KEY_ADDREFSA(sav);
703 tc->tc_sav = sav;
704 return (crypto_dispatch(crp));
705 }
706
707 /*
708 * AH input callback from the crypto driver.
709 */
710 static int
711 ah_input_cb(struct cryptop *crp)
712 {
713 char buf[INET6_ADDRSTRLEN];
714 int rplen, error, skip, protoff;
715 unsigned char calc[AH_ALEN_MAX];
716 struct mbuf *m;
717 struct cryptodesc *crd;
718 struct auth_hash *ahx;
719 struct tdb_crypto *tc;
720 struct secasvar *sav;
721 struct secasindex *saidx;
722 u_int8_t nxt;
723 caddr_t ptr;
724 int authsize;
725
726 crd = crp->crp_desc;
727
728 tc = (struct tdb_crypto *) crp->crp_opaque;
729 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
730 skip = tc->tc_skip;
731 nxt = tc->tc_nxt;
732 protoff = tc->tc_protoff;
733 m = (struct mbuf *) crp->crp_buf;
734
735 sav = tc->tc_sav;
736 IPSEC_ASSERT(sav != NULL, ("null SA!"));
737
738 saidx = &sav->sah->saidx;
739 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
740 saidx->dst.sa.sa_family == AF_INET6,
741 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
742
743 ahx = (struct auth_hash *) sav->tdb_authalgxform;
744
745 /* Check for crypto errors. */
746 if (crp->crp_etype) {
747 if (sav->tdb_cryptoid != 0)
748 sav->tdb_cryptoid = crp->crp_sid;
749
750 if (crp->crp_etype == EAGAIN)
751 return (crypto_dispatch(crp));
752
753 AHSTAT_INC(ahs_noxform);
754 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
755 error = crp->crp_etype;
756 goto bad;
757 } else {
758 AHSTAT_INC(ahs_hist[sav->alg_auth]);
759 crypto_freereq(crp); /* No longer needed. */
760 crp = NULL;
761 }
762
763 /* Shouldn't happen... */
764 if (m == NULL) {
765 AHSTAT_INC(ahs_crypto);
766 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
767 error = EINVAL;
768 goto bad;
769 }
770
771 /* Figure out header size. */
772 rplen = HDRSIZE(sav);
773 authsize = AUTHSIZE(sav);
774
775 /* Copy authenticator off the packet. */
776 m_copydata(m, skip + rplen, authsize, calc);
777
778 /* Verify authenticator. */
779 ptr = (caddr_t) (tc + 1);
780 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
781 DPRINTF(("%s: authentication hash mismatch for packet "
782 "in SA %s/%08lx\n", __func__,
783 ipsec_address(&saidx->dst, buf, sizeof(buf)),
784 (u_long) ntohl(sav->spi)));
785 AHSTAT_INC(ahs_badauth);
786 error = EACCES;
787 goto bad;
788 }
789 /* Fix the Next Protocol field. */
790 ((u_int8_t *) ptr)[protoff] = nxt;
791
792 /* Copyback the saved (uncooked) network headers. */
793 m_copyback(m, 0, skip, ptr);
794 free(tc, M_XDATA), tc = NULL; /* No longer needed */
795
796 /*
797 * Header is now authenticated.
798 */
799 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
800
801 /*
802 * Update replay sequence number, if appropriate.
803 */
804 if (sav->replay) {
805 u_int32_t seq;
806
807 m_copydata(m, skip + offsetof(struct newah, ah_seq),
808 sizeof (seq), (caddr_t) &seq);
809 if (ipsec_updatereplay(ntohl(seq), sav)) {
810 AHSTAT_INC(ahs_replay);
811 error = ENOBUFS; /*XXX as above*/
812 goto bad;
813 }
814 }
815
816 /*
817 * Remove the AH header and authenticator from the mbuf.
818 */
819 error = m_striphdr(m, skip, rplen + authsize);
820 if (error) {
821 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
822 ipsec_address(&saidx->dst, buf, sizeof(buf)),
823 (u_long) ntohl(sav->spi)));
824 AHSTAT_INC(ahs_hdrops);
825 goto bad;
826 }
827
828 switch (saidx->dst.sa.sa_family) {
829 #ifdef INET6
830 case AF_INET6:
831 error = ipsec6_common_input_cb(m, sav, skip, protoff);
832 break;
833 #endif
834 #ifdef INET
835 case AF_INET:
836 error = ipsec4_common_input_cb(m, sav, skip, protoff);
837 break;
838 #endif
839 default:
840 panic("%s: Unexpected address family: %d saidx=%p", __func__,
841 saidx->dst.sa.sa_family, saidx);
842 }
843
844 KEY_FREESAV(&sav);
845 return error;
846 bad:
847 if (sav)
848 KEY_FREESAV(&sav);
849 if (m != NULL)
850 m_freem(m);
851 if (tc != NULL)
852 free(tc, M_XDATA);
853 if (crp != NULL)
854 crypto_freereq(crp);
855 return error;
856 }
857
858 /*
859 * AH output routine, called by ipsec[46]_process_packet().
860 */
861 static int
862 ah_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
863 int skip, int protoff)
864 {
865 char buf[INET6_ADDRSTRLEN];
866 struct secasvar *sav;
867 struct auth_hash *ahx;
868 struct cryptodesc *crda;
869 struct tdb_crypto *tc;
870 struct mbuf *mi;
871 struct cryptop *crp;
872 u_int16_t iplen;
873 int error, rplen, authsize, maxpacketsize, roff;
874 u_int8_t prot;
875 struct newah *ah;
876
877 sav = isr->sav;
878 IPSEC_ASSERT(sav != NULL, ("null SA"));
879 ahx = sav->tdb_authalgxform;
880 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
881
882 AHSTAT_INC(ahs_output);
883
884 /* Figure out header size. */
885 rplen = HDRSIZE(sav);
886
887 /* Check for maximum packet size violations. */
888 switch (sav->sah->saidx.dst.sa.sa_family) {
889 #ifdef INET
890 case AF_INET:
891 maxpacketsize = IP_MAXPACKET;
892 break;
893 #endif /* INET */
894 #ifdef INET6
895 case AF_INET6:
896 maxpacketsize = IPV6_MAXPACKET;
897 break;
898 #endif /* INET6 */
899 default:
900 DPRINTF(("%s: unknown/unsupported protocol family %u, "
901 "SA %s/%08lx\n", __func__,
902 sav->sah->saidx.dst.sa.sa_family,
903 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
904 (u_long) ntohl(sav->spi)));
905 AHSTAT_INC(ahs_nopf);
906 error = EPFNOSUPPORT;
907 goto bad;
908 }
909 authsize = AUTHSIZE(sav);
910 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
911 DPRINTF(("%s: packet in SA %s/%08lx got too big "
912 "(len %u, max len %u)\n", __func__,
913 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
914 (u_long) ntohl(sav->spi),
915 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
916 AHSTAT_INC(ahs_toobig);
917 error = EMSGSIZE;
918 goto bad;
919 }
920
921 /* Update the counters. */
922 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
923
924 m = m_unshare(m, M_NOWAIT);
925 if (m == NULL) {
926 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
927 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
928 (u_long) ntohl(sav->spi)));
929 AHSTAT_INC(ahs_hdrops);
930 error = ENOBUFS;
931 goto bad;
932 }
933
934 /* Inject AH header. */
935 mi = m_makespace(m, skip, rplen + authsize, &roff);
936 if (mi == NULL) {
937 DPRINTF(("%s: failed to inject %u byte AH header for SA "
938 "%s/%08lx\n", __func__,
939 rplen + authsize,
940 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
941 (u_long) ntohl(sav->spi)));
942 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
943 error = ENOBUFS;
944 goto bad;
945 }
946
947 /*
948 * The AH header is guaranteed by m_makespace() to be in
949 * contiguous memory, at roff bytes offset into the returned mbuf.
950 */
951 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
952
953 /* Initialize the AH header. */
954 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
955 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
956 ah->ah_reserve = 0;
957 ah->ah_spi = sav->spi;
958
959 /* Zeroize authenticator. */
960 m_copyback(m, skip + rplen, authsize, ipseczeroes);
961
962 /* Insert packet replay counter, as requested. */
963 if (sav->replay) {
964 if (sav->replay->count == ~0 &&
965 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
966 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
967 __func__, ipsec_address(&sav->sah->saidx.dst, buf,
968 sizeof(buf)), (u_long) ntohl(sav->spi)));
969 AHSTAT_INC(ahs_wrap);
970 error = EINVAL;
971 goto bad;
972 }
973 #ifdef REGRESSION
974 /* Emulate replay attack when ipsec_replay is TRUE. */
975 if (!V_ipsec_replay)
976 #endif
977 sav->replay->count++;
978 ah->ah_seq = htonl(sav->replay->count);
979 }
980
981 /* Get crypto descriptors. */
982 crp = crypto_getreq(1);
983 if (crp == NULL) {
984 DPRINTF(("%s: failed to acquire crypto descriptors\n",
985 __func__));
986 AHSTAT_INC(ahs_crypto);
987 error = ENOBUFS;
988 goto bad;
989 }
990
991 crda = crp->crp_desc;
992
993 crda->crd_skip = 0;
994 crda->crd_inject = skip + rplen;
995 crda->crd_len = m->m_pkthdr.len;
996
997 /* Authentication operation. */
998 crda->crd_alg = ahx->type;
999 crda->crd_key = sav->key_auth->key_data;
1000 crda->crd_klen = _KEYBITS(sav->key_auth);
1001
1002 /* Allocate IPsec-specific opaque crypto info. */
1003 tc = (struct tdb_crypto *) malloc(
1004 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1005 if (tc == NULL) {
1006 crypto_freereq(crp);
1007 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
1008 AHSTAT_INC(ahs_crypto);
1009 error = ENOBUFS;
1010 goto bad;
1011 }
1012
1013 /* Save the skipped portion of the packet. */
1014 m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1015
1016 /*
1017 * Fix IP header length on the header used for
1018 * authentication. We don't need to fix the original
1019 * header length as it will be fixed by our caller.
1020 */
1021 switch (sav->sah->saidx.dst.sa.sa_family) {
1022 #ifdef INET
1023 case AF_INET:
1024 bcopy(((caddr_t)(tc + 1)) +
1025 offsetof(struct ip, ip_len),
1026 (caddr_t) &iplen, sizeof(u_int16_t));
1027 iplen = htons(ntohs(iplen) + rplen + authsize);
1028 m_copyback(m, offsetof(struct ip, ip_len),
1029 sizeof(u_int16_t), (caddr_t) &iplen);
1030 break;
1031 #endif /* INET */
1032
1033 #ifdef INET6
1034 case AF_INET6:
1035 bcopy(((caddr_t)(tc + 1)) +
1036 offsetof(struct ip6_hdr, ip6_plen),
1037 (caddr_t) &iplen, sizeof(u_int16_t));
1038 iplen = htons(ntohs(iplen) + rplen + authsize);
1039 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1040 sizeof(u_int16_t), (caddr_t) &iplen);
1041 break;
1042 #endif /* INET6 */
1043 }
1044
1045 /* Fix the Next Header field in saved header. */
1046 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1047
1048 /* Update the Next Protocol field in the IP header. */
1049 prot = IPPROTO_AH;
1050 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1051
1052 /* "Massage" the packet headers for crypto processing. */
1053 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1054 skip, ahx->type, 1);
1055 if (error != 0) {
1056 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1057 free(tc, M_XDATA);
1058 crypto_freereq(crp);
1059 goto bad;
1060 }
1061
1062 /* Crypto operation descriptor. */
1063 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1064 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1065 crp->crp_buf = (caddr_t) m;
1066 crp->crp_callback = ah_output_cb;
1067 crp->crp_sid = sav->tdb_cryptoid;
1068 crp->crp_opaque = (caddr_t) tc;
1069
1070 /* These are passed as-is to the callback. */
1071 key_addref(isr->sp);
1072 tc->tc_isr = isr;
1073 KEY_ADDREFSA(sav);
1074 tc->tc_sav = sav;
1075 tc->tc_spi = sav->spi;
1076 tc->tc_dst = sav->sah->saidx.dst;
1077 tc->tc_proto = sav->sah->saidx.proto;
1078 tc->tc_skip = skip;
1079 tc->tc_protoff = protoff;
1080
1081 return crypto_dispatch(crp);
1082 bad:
1083 if (m)
1084 m_freem(m);
1085 return (error);
1086 }
1087
1088 /*
1089 * AH output callback from the crypto driver.
1090 */
1091 static int
1092 ah_output_cb(struct cryptop *crp)
1093 {
1094 int skip, protoff, error;
1095 struct tdb_crypto *tc;
1096 struct ipsecrequest *isr;
1097 struct secasvar *sav;
1098 struct mbuf *m;
1099 caddr_t ptr;
1100
1101 tc = (struct tdb_crypto *) crp->crp_opaque;
1102 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
1103 skip = tc->tc_skip;
1104 protoff = tc->tc_protoff;
1105 ptr = (caddr_t) (tc + 1);
1106 m = (struct mbuf *) crp->crp_buf;
1107
1108 isr = tc->tc_isr;
1109 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
1110 IPSECREQUEST_LOCK(isr);
1111 sav = tc->tc_sav;
1112 /* With the isr lock released SA pointer can be updated. */
1113 if (sav != isr->sav) {
1114 AHSTAT_INC(ahs_notdb);
1115 DPRINTF(("%s: SA expired while in crypto\n", __func__));
1116 error = ENOBUFS; /*XXX*/
1117 goto bad;
1118 }
1119
1120 /* Check for crypto errors. */
1121 if (crp->crp_etype) {
1122 if (sav->tdb_cryptoid != 0)
1123 sav->tdb_cryptoid = crp->crp_sid;
1124
1125 if (crp->crp_etype == EAGAIN) {
1126 IPSECREQUEST_UNLOCK(isr);
1127 return (crypto_dispatch(crp));
1128 }
1129
1130 AHSTAT_INC(ahs_noxform);
1131 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1132 error = crp->crp_etype;
1133 goto bad;
1134 }
1135
1136 /* Shouldn't happen... */
1137 if (m == NULL) {
1138 AHSTAT_INC(ahs_crypto);
1139 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1140 error = EINVAL;
1141 goto bad;
1142 }
1143 AHSTAT_INC(ahs_hist[sav->alg_auth]);
1144
1145 /*
1146 * Copy original headers (with the new protocol number) back
1147 * in place.
1148 */
1149 m_copyback(m, 0, skip, ptr);
1150
1151 /* No longer needed. */
1152 free(tc, M_XDATA);
1153 crypto_freereq(crp);
1154
1155 #ifdef REGRESSION
1156 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1157 if (V_ipsec_integrity) {
1158 int alen;
1159
1160 /*
1161 * Corrupt HMAC if we want to test integrity verification of
1162 * the other side.
1163 */
1164 alen = AUTHSIZE(sav);
1165 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1166 }
1167 #endif
1168
1169 /* NB: m is reclaimed by ipsec_process_done. */
1170 error = ipsec_process_done(m, isr);
1171 KEY_FREESAV(&sav);
1172 IPSECREQUEST_UNLOCK(isr);
1173 KEY_FREESP(&isr->sp);
1174 return (error);
1175 bad:
1176 if (sav)
1177 KEY_FREESAV(&sav);
1178 IPSECREQUEST_UNLOCK(isr);
1179 KEY_FREESP(&isr->sp);
1180 if (m)
1181 m_freem(m);
1182 free(tc, M_XDATA);
1183 crypto_freereq(crp);
1184 return (error);
1185 }
1186
1187 static struct xformsw ah_xformsw = {
1188 XF_AH, XFT_AUTH, "IPsec AH",
1189 ah_init, ah_zeroize, ah_input, ah_output,
1190 };
1191
1192 static void
1193 ah_attach(void)
1194 {
1195
1196 xform_register(&ah_xformsw);
1197 }
1198
1199 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
Cache object: 290804f70592f1f886af38664b0e7bd3
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