1 /* $FreeBSD: releng/12.0/sys/netipsec/xform_ah.c 336439 2018-07-18 00:56:25Z cem $ */
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/mutex.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(const 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 size_t
145 ah_hdrsiz(struct secasvar *sav)
146 {
147 size_t size;
148
149 if (sav != NULL) {
150 int authsize, rplen, align;
151
152 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
153 /*XXX not right for null algorithm--does it matter??*/
154
155 /* RFC4302: use the correct alignment. */
156 align = sizeof(uint32_t);
157 #ifdef INET6
158 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) {
159 align = sizeof(uint64_t);
160 }
161 #endif
162 rplen = HDRSIZE(sav);
163 authsize = AUTHSIZE(sav);
164 size = roundup(rplen + authsize, align);
165 } else {
166 /* default guess */
167 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
168 }
169 return size;
170 }
171
172 /*
173 * NB: public for use by esp_init.
174 */
175 int
176 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
177 {
178 const struct auth_hash *thash;
179 int keylen;
180
181 thash = auth_algorithm_lookup(sav->alg_auth);
182 if (thash == NULL) {
183 DPRINTF(("%s: unsupported authentication algorithm %u\n",
184 __func__, sav->alg_auth));
185 return EINVAL;
186 }
187 /*
188 * Verify the replay state block allocation is consistent with
189 * the protocol type. We check here so we can make assumptions
190 * later during protocol processing.
191 */
192 /* NB: replay state is setup elsewhere (sigh) */
193 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
194 DPRINTF(("%s: replay state block inconsistency, "
195 "%s algorithm %s replay state\n", __func__,
196 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
197 sav->replay == NULL ? "without" : "with"));
198 return EINVAL;
199 }
200 if (sav->key_auth == NULL) {
201 DPRINTF(("%s: no authentication key for %s algorithm\n",
202 __func__, thash->name));
203 return EINVAL;
204 }
205 keylen = _KEYLEN(sav->key_auth);
206 if (keylen > thash->keysize && thash->keysize != 0) {
207 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
208 "keysize less than %d\n", __func__,
209 keylen, thash->name, thash->keysize));
210 return EINVAL;
211 }
212
213 sav->tdb_xform = xsp;
214 sav->tdb_authalgxform = thash;
215
216 /* Initialize crypto session. */
217 bzero(cria, sizeof (*cria));
218 cria->cri_alg = sav->tdb_authalgxform->type;
219 cria->cri_klen = _KEYBITS(sav->key_auth);
220 cria->cri_key = sav->key_auth->key_data;
221 cria->cri_mlen = AUTHSIZE(sav);
222
223 return 0;
224 }
225
226 /*
227 * ah_init() is called when an SPI is being set up.
228 */
229 static int
230 ah_init(struct secasvar *sav, struct xformsw *xsp)
231 {
232 struct cryptoini cria;
233 int error;
234
235 error = ah_init0(sav, xsp, &cria);
236 return error ? error :
237 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
238 }
239
240 /*
241 * Paranoia.
242 *
243 * NB: public for use by esp_zeroize (XXX).
244 */
245 int
246 ah_zeroize(struct secasvar *sav)
247 {
248
249 if (sav->key_auth)
250 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
251
252 crypto_freesession(sav->tdb_cryptoid);
253 sav->tdb_cryptoid = NULL;
254 sav->tdb_authalgxform = NULL;
255 sav->tdb_xform = NULL;
256 return 0;
257 }
258
259 /*
260 * Massage IPv4/IPv6 headers for AH processing.
261 */
262 static int
263 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
264 {
265 struct mbuf *m = *m0;
266 unsigned char *ptr;
267 int off, count;
268
269 #ifdef INET
270 struct ip *ip;
271 #endif /* INET */
272
273 #ifdef INET6
274 struct ip6_ext *ip6e;
275 struct ip6_hdr ip6;
276 int ad, alloc, nxt, noff;
277 #endif /* INET6 */
278
279 switch (proto) {
280 #ifdef INET
281 case AF_INET:
282 /*
283 * This is the least painful way of dealing with IPv4 header
284 * and option processing -- just make sure they're in
285 * contiguous memory.
286 */
287 *m0 = m = m_pullup(m, skip);
288 if (m == NULL) {
289 DPRINTF(("%s: m_pullup failed\n", __func__));
290 return ENOBUFS;
291 }
292
293 /* Fix the IP header */
294 ip = mtod(m, struct ip *);
295 if (V_ah_cleartos)
296 ip->ip_tos = 0;
297 ip->ip_ttl = 0;
298 ip->ip_sum = 0;
299
300 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
301 ip->ip_off &= htons(IP_DF);
302 else
303 ip->ip_off = htons(0);
304
305 ptr = mtod(m, unsigned char *);
306
307 /* IPv4 option processing */
308 for (off = sizeof(struct ip); off < skip;) {
309 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
310 off + 1 < skip)
311 ;
312 else {
313 DPRINTF(("%s: illegal IPv4 option length for "
314 "option %d\n", __func__, ptr[off]));
315
316 m_freem(m);
317 return EINVAL;
318 }
319
320 switch (ptr[off]) {
321 case IPOPT_EOL:
322 off = skip; /* End the loop. */
323 break;
324
325 case IPOPT_NOP:
326 off++;
327 break;
328
329 case IPOPT_SECURITY: /* 0x82 */
330 case 0x85: /* Extended security. */
331 case 0x86: /* Commercial security. */
332 case 0x94: /* Router alert */
333 case 0x95: /* RFC1770 */
334 /* Sanity check for option length. */
335 if (ptr[off + 1] < 2) {
336 DPRINTF(("%s: illegal IPv4 option "
337 "length for option %d\n",
338 __func__, ptr[off]));
339
340 m_freem(m);
341 return EINVAL;
342 }
343
344 off += ptr[off + 1];
345 break;
346
347 case IPOPT_LSRR:
348 case IPOPT_SSRR:
349 /* Sanity check for option length. */
350 if (ptr[off + 1] < 2) {
351 DPRINTF(("%s: illegal IPv4 option "
352 "length for option %d\n",
353 __func__, ptr[off]));
354
355 m_freem(m);
356 return EINVAL;
357 }
358
359 /*
360 * On output, if we have either of the
361 * source routing options, we should
362 * swap the destination address of the
363 * IP header with the last address
364 * specified in the option, as that is
365 * what the destination's IP header
366 * will look like.
367 */
368 if (out)
369 bcopy(ptr + off + ptr[off + 1] -
370 sizeof(struct in_addr),
371 &(ip->ip_dst), sizeof(struct in_addr));
372
373 /* Fall through */
374 default:
375 /* Sanity check for option length. */
376 if (ptr[off + 1] < 2) {
377 DPRINTF(("%s: illegal IPv4 option "
378 "length for option %d\n",
379 __func__, ptr[off]));
380 m_freem(m);
381 return EINVAL;
382 }
383
384 /* Zeroize all other options. */
385 count = ptr[off + 1];
386 bcopy(ipseczeroes, ptr + off, count);
387 off += count;
388 break;
389 }
390
391 /* Sanity check. */
392 if (off > skip) {
393 DPRINTF(("%s: malformed IPv4 options header\n",
394 __func__));
395
396 m_freem(m);
397 return EINVAL;
398 }
399 }
400
401 break;
402 #endif /* INET */
403
404 #ifdef INET6
405 case AF_INET6: /* Ugly... */
406 /* Copy and "cook" the IPv6 header. */
407 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
408
409 /* We don't do IPv6 Jumbograms. */
410 if (ip6.ip6_plen == 0) {
411 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
412 m_freem(m);
413 return EMSGSIZE;
414 }
415
416 ip6.ip6_flow = 0;
417 ip6.ip6_hlim = 0;
418 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
419 ip6.ip6_vfc |= IPV6_VERSION;
420
421 /* Scoped address handling. */
422 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
423 ip6.ip6_src.s6_addr16[1] = 0;
424 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
425 ip6.ip6_dst.s6_addr16[1] = 0;
426
427 /* Done with IPv6 header. */
428 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
429
430 /* Let's deal with the remaining headers (if any). */
431 if (skip - sizeof(struct ip6_hdr) > 0) {
432 if (m->m_len <= skip) {
433 ptr = (unsigned char *) malloc(
434 skip - sizeof(struct ip6_hdr),
435 M_XDATA, M_NOWAIT);
436 if (ptr == NULL) {
437 DPRINTF(("%s: failed to allocate memory"
438 "for IPv6 headers\n",__func__));
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 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
460
461 for (off = 0; off < skip - sizeof(struct ip6_hdr);)
462 switch (nxt) {
463 case IPPROTO_HOPOPTS:
464 case IPPROTO_DSTOPTS:
465 ip6e = (struct ip6_ext *)(ptr + off);
466 noff = off + ((ip6e->ip6e_len + 1) << 3);
467
468 /* Sanity check. */
469 if (noff > skip - sizeof(struct ip6_hdr))
470 goto error6;
471
472 /*
473 * Zero out mutable options.
474 */
475 for (count = off + sizeof(struct ip6_ext);
476 count < noff;) {
477 if (ptr[count] == IP6OPT_PAD1) {
478 count++;
479 continue; /* Skip padding. */
480 }
481
482 ad = ptr[count + 1] + 2;
483 if (count + ad > noff)
484 goto error6;
485
486 if (ptr[count] & IP6OPT_MUTABLE)
487 memset(ptr + count, 0, ad);
488 count += ad;
489 }
490
491 if (count != noff)
492 goto error6;
493
494 /* Advance. */
495 off += ((ip6e->ip6e_len + 1) << 3);
496 nxt = ip6e->ip6e_nxt;
497 break;
498
499 case IPPROTO_ROUTING:
500 /*
501 * Always include routing headers in
502 * computation.
503 */
504 ip6e = (struct ip6_ext *) (ptr + off);
505 off += ((ip6e->ip6e_len + 1) << 3);
506 nxt = ip6e->ip6e_nxt;
507 break;
508
509 default:
510 DPRINTF(("%s: unexpected IPv6 header type %d",
511 __func__, off));
512 error6:
513 if (alloc)
514 free(ptr, M_XDATA);
515 m_freem(m);
516 return EINVAL;
517 }
518
519 /* Copyback and free, if we allocated. */
520 if (alloc) {
521 m_copyback(m, sizeof(struct ip6_hdr),
522 skip - sizeof(struct ip6_hdr), ptr);
523 free(ptr, M_XDATA);
524 }
525
526 break;
527 #endif /* INET6 */
528 }
529
530 return 0;
531 }
532
533 /*
534 * ah_input() gets called to verify that an input packet
535 * passes authentication.
536 */
537 static int
538 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
539 {
540 IPSEC_DEBUG_DECLARE(char buf[128]);
541 const struct auth_hash *ahx;
542 struct cryptodesc *crda;
543 struct cryptop *crp;
544 struct xform_data *xd;
545 struct newah *ah;
546 crypto_session_t cryptoid;
547 int hl, rplen, authsize, ahsize, error;
548
549 IPSEC_ASSERT(sav != NULL, ("null SA"));
550 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
551 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
552 ("null authentication xform"));
553
554 /* Figure out header size. */
555 rplen = HDRSIZE(sav);
556
557 /* XXX don't pullup, just copy header */
558 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
559 if (ah == NULL) {
560 DPRINTF(("ah_input: cannot pullup header\n"));
561 AHSTAT_INC(ahs_hdrops); /*XXX*/
562 error = ENOBUFS;
563 goto bad;
564 }
565
566 /* Check replay window, if applicable. */
567 SECASVAR_LOCK(sav);
568 if (sav->replay != NULL && sav->replay->wsize != 0 &&
569 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) {
570 SECASVAR_UNLOCK(sav);
571 AHSTAT_INC(ahs_replay);
572 DPRINTF(("%s: packet replay failure: %s\n", __func__,
573 ipsec_sa2str(sav, buf, sizeof(buf))));
574 error = EACCES;
575 goto bad;
576 }
577 cryptoid = sav->tdb_cryptoid;
578 SECASVAR_UNLOCK(sav);
579
580 /* Verify AH header length. */
581 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t));
582 ahx = sav->tdb_authalgxform;
583 authsize = AUTHSIZE(sav);
584 ahsize = ah_hdrsiz(sav);
585 if (hl != ahsize) {
586 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
587 " for packet in SA %s/%08lx\n", __func__, hl,
588 (u_long)ahsize,
589 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
590 (u_long) ntohl(sav->spi)));
591 AHSTAT_INC(ahs_badauthl);
592 error = EACCES;
593 goto bad;
594 }
595 if (skip + ahsize > m->m_pkthdr.len) {
596 DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
597 " for packet in SA %s/%08lx\n", __func__,
598 m->m_pkthdr.len, (u_long)(skip + ahsize),
599 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
600 (u_long) ntohl(sav->spi)));
601 AHSTAT_INC(ahs_badauthl);
602 error = EACCES;
603 goto bad;
604 }
605 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
606
607 /* Get crypto descriptors. */
608 crp = crypto_getreq(1);
609 if (crp == NULL) {
610 DPRINTF(("%s: failed to acquire crypto descriptor\n",
611 __func__));
612 AHSTAT_INC(ahs_crypto);
613 error = ENOBUFS;
614 goto bad;
615 }
616
617 crda = crp->crp_desc;
618 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
619
620 crda->crd_skip = 0;
621 crda->crd_len = m->m_pkthdr.len;
622 crda->crd_inject = skip + rplen;
623
624 /* Authentication operation. */
625 crda->crd_alg = ahx->type;
626 crda->crd_klen = _KEYBITS(sav->key_auth);
627 crda->crd_key = sav->key_auth->key_data;
628
629 /* Allocate IPsec-specific opaque crypto info. */
630 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA,
631 M_NOWAIT | M_ZERO);
632 if (xd == NULL) {
633 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
634 AHSTAT_INC(ahs_crypto);
635 crypto_freereq(crp);
636 error = ENOBUFS;
637 goto bad;
638 }
639
640 /*
641 * Save the authenticator, the skipped portion of the packet,
642 * and the AH header.
643 */
644 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1));
645
646 /* Zeroize the authenticator on the packet. */
647 m_copyback(m, skip + rplen, authsize, ipseczeroes);
648
649 /* Save ah_nxt, since ah pointer can become invalid after "massage" */
650 hl = ah->ah_nxt;
651
652 /* "Massage" the packet headers for crypto processing. */
653 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
654 skip, ahx->type, 0);
655 if (error != 0) {
656 /* NB: mbuf is free'd by ah_massage_headers */
657 AHSTAT_INC(ahs_hdrops);
658 free(xd, M_XDATA);
659 crypto_freereq(crp);
660 key_freesav(&sav);
661 return (error);
662 }
663
664 /* Crypto operation descriptor. */
665 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
666 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
667 if (V_async_crypto)
668 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
669 crp->crp_buf = (caddr_t) m;
670 crp->crp_callback = ah_input_cb;
671 crp->crp_session = cryptoid;
672 crp->crp_opaque = (caddr_t) xd;
673
674 /* These are passed as-is to the callback. */
675 xd->sav = sav;
676 xd->nxt = hl;
677 xd->protoff = protoff;
678 xd->skip = skip;
679 xd->cryptoid = cryptoid;
680 xd->vnet = curvnet;
681 return (crypto_dispatch(crp));
682 bad:
683 m_freem(m);
684 key_freesav(&sav);
685 return (error);
686 }
687
688 /*
689 * AH input callback from the crypto driver.
690 */
691 static int
692 ah_input_cb(struct cryptop *crp)
693 {
694 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
695 unsigned char calc[AH_ALEN_MAX];
696 struct mbuf *m;
697 struct xform_data *xd;
698 struct secasvar *sav;
699 struct secasindex *saidx;
700 caddr_t ptr;
701 crypto_session_t cryptoid;
702 int authsize, rplen, ahsize, error, skip, protoff;
703 uint8_t nxt;
704
705 m = (struct mbuf *) crp->crp_buf;
706 xd = (struct xform_data *) crp->crp_opaque;
707 CURVNET_SET(xd->vnet);
708 sav = xd->sav;
709 skip = xd->skip;
710 nxt = xd->nxt;
711 protoff = xd->protoff;
712 cryptoid = xd->cryptoid;
713 saidx = &sav->sah->saidx;
714 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
715 saidx->dst.sa.sa_family == AF_INET6,
716 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
717
718 /* Check for crypto errors. */
719 if (crp->crp_etype) {
720 if (crp->crp_etype == EAGAIN) {
721 /* Reset the session ID */
722 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
723 crypto_freesession(cryptoid);
724 xd->cryptoid = crp->crp_session;
725 CURVNET_RESTORE();
726 return (crypto_dispatch(crp));
727 }
728 AHSTAT_INC(ahs_noxform);
729 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
730 error = crp->crp_etype;
731 goto bad;
732 } else {
733 AHSTAT_INC(ahs_hist[sav->alg_auth]);
734 crypto_freereq(crp); /* No longer needed. */
735 crp = NULL;
736 }
737
738 /* Shouldn't happen... */
739 if (m == NULL) {
740 AHSTAT_INC(ahs_crypto);
741 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
742 error = EINVAL;
743 goto bad;
744 }
745
746 /* Figure out header size. */
747 rplen = HDRSIZE(sav);
748 authsize = AUTHSIZE(sav);
749 ahsize = ah_hdrsiz(sav);
750
751 /* Copy authenticator off the packet. */
752 m_copydata(m, skip + rplen, authsize, calc);
753
754 /* Verify authenticator. */
755 ptr = (caddr_t) (xd + 1);
756 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
757 DPRINTF(("%s: authentication hash mismatch for packet "
758 "in SA %s/%08lx\n", __func__,
759 ipsec_address(&saidx->dst, buf, sizeof(buf)),
760 (u_long) ntohl(sav->spi)));
761 AHSTAT_INC(ahs_badauth);
762 error = EACCES;
763 goto bad;
764 }
765 /* Fix the Next Protocol field. */
766 ((uint8_t *) ptr)[protoff] = nxt;
767
768 /* Copyback the saved (uncooked) network headers. */
769 m_copyback(m, 0, skip, ptr);
770 free(xd, M_XDATA), xd = NULL; /* No longer needed */
771
772 /*
773 * Header is now authenticated.
774 */
775 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
776
777 /*
778 * Update replay sequence number, if appropriate.
779 */
780 if (sav->replay) {
781 u_int32_t seq;
782
783 m_copydata(m, skip + offsetof(struct newah, ah_seq),
784 sizeof (seq), (caddr_t) &seq);
785 SECASVAR_LOCK(sav);
786 if (ipsec_updatereplay(ntohl(seq), sav)) {
787 SECASVAR_UNLOCK(sav);
788 AHSTAT_INC(ahs_replay);
789 error = EACCES;
790 goto bad;
791 }
792 SECASVAR_UNLOCK(sav);
793 }
794
795 /*
796 * Remove the AH header and authenticator from the mbuf.
797 */
798 error = m_striphdr(m, skip, ahsize);
799 if (error) {
800 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
801 ipsec_address(&saidx->dst, buf, sizeof(buf)),
802 (u_long) ntohl(sav->spi)));
803 AHSTAT_INC(ahs_hdrops);
804 goto bad;
805 }
806
807 switch (saidx->dst.sa.sa_family) {
808 #ifdef INET6
809 case AF_INET6:
810 error = ipsec6_common_input_cb(m, sav, skip, protoff);
811 break;
812 #endif
813 #ifdef INET
814 case AF_INET:
815 error = ipsec4_common_input_cb(m, sav, skip, protoff);
816 break;
817 #endif
818 default:
819 panic("%s: Unexpected address family: %d saidx=%p", __func__,
820 saidx->dst.sa.sa_family, saidx);
821 }
822 CURVNET_RESTORE();
823 return error;
824 bad:
825 CURVNET_RESTORE();
826 if (sav)
827 key_freesav(&sav);
828 if (m != NULL)
829 m_freem(m);
830 if (xd != NULL)
831 free(xd, M_XDATA);
832 if (crp != NULL)
833 crypto_freereq(crp);
834 return error;
835 }
836
837 /*
838 * AH output routine, called by ipsec[46]_perform_request().
839 */
840 static int
841 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
842 u_int idx, int skip, int protoff)
843 {
844 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
845 const struct auth_hash *ahx;
846 struct cryptodesc *crda;
847 struct xform_data *xd;
848 struct mbuf *mi;
849 struct cryptop *crp;
850 struct newah *ah;
851 crypto_session_t cryptoid;
852 uint16_t iplen;
853 int error, rplen, authsize, ahsize, maxpacketsize, roff;
854 uint8_t prot;
855
856 IPSEC_ASSERT(sav != NULL, ("null SA"));
857 ahx = sav->tdb_authalgxform;
858 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
859
860 AHSTAT_INC(ahs_output);
861
862 /* Figure out header size. */
863 rplen = HDRSIZE(sav);
864 authsize = AUTHSIZE(sav);
865 ahsize = ah_hdrsiz(sav);
866
867 /* Check for maximum packet size violations. */
868 switch (sav->sah->saidx.dst.sa.sa_family) {
869 #ifdef INET
870 case AF_INET:
871 maxpacketsize = IP_MAXPACKET;
872 break;
873 #endif /* INET */
874 #ifdef INET6
875 case AF_INET6:
876 maxpacketsize = IPV6_MAXPACKET;
877 break;
878 #endif /* INET6 */
879 default:
880 DPRINTF(("%s: unknown/unsupported protocol family %u, "
881 "SA %s/%08lx\n", __func__,
882 sav->sah->saidx.dst.sa.sa_family,
883 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
884 (u_long) ntohl(sav->spi)));
885 AHSTAT_INC(ahs_nopf);
886 error = EPFNOSUPPORT;
887 goto bad;
888 }
889 if (ahsize + m->m_pkthdr.len > maxpacketsize) {
890 DPRINTF(("%s: packet in SA %s/%08lx got too big "
891 "(len %u, max len %u)\n", __func__,
892 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
893 (u_long) ntohl(sav->spi),
894 ahsize + m->m_pkthdr.len, maxpacketsize));
895 AHSTAT_INC(ahs_toobig);
896 error = EMSGSIZE;
897 goto bad;
898 }
899
900 /* Update the counters. */
901 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
902
903 m = m_unshare(m, M_NOWAIT);
904 if (m == NULL) {
905 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
906 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
907 (u_long) ntohl(sav->spi)));
908 AHSTAT_INC(ahs_hdrops);
909 error = ENOBUFS;
910 goto bad;
911 }
912
913 /* Inject AH header. */
914 mi = m_makespace(m, skip, ahsize, &roff);
915 if (mi == NULL) {
916 DPRINTF(("%s: failed to inject %u byte AH header for SA "
917 "%s/%08lx\n", __func__, ahsize,
918 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
919 (u_long) ntohl(sav->spi)));
920 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
921 error = ENOBUFS;
922 goto bad;
923 }
924
925 /*
926 * The AH header is guaranteed by m_makespace() to be in
927 * contiguous memory, at roff bytes offset into the returned mbuf.
928 */
929 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
930
931 /* Initialize the AH header. */
932 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
933 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t);
934 ah->ah_reserve = 0;
935 ah->ah_spi = sav->spi;
936
937 /* Zeroize authenticator. */
938 m_copyback(m, skip + rplen, authsize, ipseczeroes);
939
940 /* Zeroize padding */
941 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize),
942 ipseczeroes);
943
944 /* Insert packet replay counter, as requested. */
945 SECASVAR_LOCK(sav);
946 if (sav->replay) {
947 if (sav->replay->count == ~0 &&
948 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
949 SECASVAR_UNLOCK(sav);
950 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
951 __func__, ipsec_address(&sav->sah->saidx.dst, buf,
952 sizeof(buf)), (u_long) ntohl(sav->spi)));
953 AHSTAT_INC(ahs_wrap);
954 error = EACCES;
955 goto bad;
956 }
957 #ifdef REGRESSION
958 /* Emulate replay attack when ipsec_replay is TRUE. */
959 if (!V_ipsec_replay)
960 #endif
961 sav->replay->count++;
962 ah->ah_seq = htonl(sav->replay->count);
963 }
964 cryptoid = sav->tdb_cryptoid;
965 SECASVAR_UNLOCK(sav);
966
967 /* Get crypto descriptors. */
968 crp = crypto_getreq(1);
969 if (crp == NULL) {
970 DPRINTF(("%s: failed to acquire crypto descriptors\n",
971 __func__));
972 AHSTAT_INC(ahs_crypto);
973 error = ENOBUFS;
974 goto bad;
975 }
976
977 crda = crp->crp_desc;
978 crda->crd_skip = 0;
979 crda->crd_inject = skip + rplen;
980 crda->crd_len = m->m_pkthdr.len;
981
982 /* Authentication operation. */
983 crda->crd_alg = ahx->type;
984 crda->crd_key = sav->key_auth->key_data;
985 crda->crd_klen = _KEYBITS(sav->key_auth);
986
987 /* Allocate IPsec-specific opaque crypto info. */
988 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA,
989 M_NOWAIT | M_ZERO);
990 if (xd == NULL) {
991 crypto_freereq(crp);
992 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
993 AHSTAT_INC(ahs_crypto);
994 error = ENOBUFS;
995 goto bad;
996 }
997
998 /* Save the skipped portion of the packet. */
999 m_copydata(m, 0, skip, (caddr_t) (xd + 1));
1000
1001 /*
1002 * Fix IP header length on the header used for
1003 * authentication. We don't need to fix the original
1004 * header length as it will be fixed by our caller.
1005 */
1006 switch (sav->sah->saidx.dst.sa.sa_family) {
1007 #ifdef INET
1008 case AF_INET:
1009 bcopy(((caddr_t)(xd + 1)) +
1010 offsetof(struct ip, ip_len),
1011 (caddr_t) &iplen, sizeof(u_int16_t));
1012 iplen = htons(ntohs(iplen) + ahsize);
1013 m_copyback(m, offsetof(struct ip, ip_len),
1014 sizeof(u_int16_t), (caddr_t) &iplen);
1015 break;
1016 #endif /* INET */
1017
1018 #ifdef INET6
1019 case AF_INET6:
1020 bcopy(((caddr_t)(xd + 1)) +
1021 offsetof(struct ip6_hdr, ip6_plen),
1022 (caddr_t) &iplen, sizeof(uint16_t));
1023 iplen = htons(ntohs(iplen) + ahsize);
1024 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1025 sizeof(uint16_t), (caddr_t) &iplen);
1026 break;
1027 #endif /* INET6 */
1028 }
1029
1030 /* Fix the Next Header field in saved header. */
1031 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH;
1032
1033 /* Update the Next Protocol field in the IP header. */
1034 prot = IPPROTO_AH;
1035 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot);
1036
1037 /* "Massage" the packet headers for crypto processing. */
1038 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1039 skip, ahx->type, 1);
1040 if (error != 0) {
1041 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1042 free(xd, M_XDATA);
1043 crypto_freereq(crp);
1044 goto bad;
1045 }
1046
1047 /* Crypto operation descriptor. */
1048 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1049 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1050 if (V_async_crypto)
1051 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
1052 crp->crp_buf = (caddr_t) m;
1053 crp->crp_callback = ah_output_cb;
1054 crp->crp_session = cryptoid;
1055 crp->crp_opaque = (caddr_t) xd;
1056
1057 /* These are passed as-is to the callback. */
1058 xd->sp = sp;
1059 xd->sav = sav;
1060 xd->skip = skip;
1061 xd->idx = idx;
1062 xd->cryptoid = cryptoid;
1063 xd->vnet = curvnet;
1064
1065 return crypto_dispatch(crp);
1066 bad:
1067 if (m)
1068 m_freem(m);
1069 key_freesav(&sav);
1070 key_freesp(&sp);
1071 return (error);
1072 }
1073
1074 /*
1075 * AH output callback from the crypto driver.
1076 */
1077 static int
1078 ah_output_cb(struct cryptop *crp)
1079 {
1080 struct xform_data *xd;
1081 struct secpolicy *sp;
1082 struct secasvar *sav;
1083 struct mbuf *m;
1084 crypto_session_t cryptoid;
1085 caddr_t ptr;
1086 u_int idx;
1087 int skip, error;
1088
1089 m = (struct mbuf *) crp->crp_buf;
1090 xd = (struct xform_data *) crp->crp_opaque;
1091 CURVNET_SET(xd->vnet);
1092 sp = xd->sp;
1093 sav = xd->sav;
1094 skip = xd->skip;
1095 idx = xd->idx;
1096 cryptoid = xd->cryptoid;
1097 ptr = (caddr_t) (xd + 1);
1098
1099 /* Check for crypto errors. */
1100 if (crp->crp_etype) {
1101 if (crp->crp_etype == EAGAIN) {
1102 /* Reset the session ID */
1103 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
1104 crypto_freesession(cryptoid);
1105 xd->cryptoid = crp->crp_session;
1106 CURVNET_RESTORE();
1107 return (crypto_dispatch(crp));
1108 }
1109 AHSTAT_INC(ahs_noxform);
1110 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1111 error = crp->crp_etype;
1112 m_freem(m);
1113 goto bad;
1114 }
1115
1116 /* Shouldn't happen... */
1117 if (m == NULL) {
1118 AHSTAT_INC(ahs_crypto);
1119 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1120 error = EINVAL;
1121 goto bad;
1122 }
1123 /*
1124 * Copy original headers (with the new protocol number) back
1125 * in place.
1126 */
1127 m_copyback(m, 0, skip, ptr);
1128
1129 free(xd, M_XDATA);
1130 crypto_freereq(crp);
1131 AHSTAT_INC(ahs_hist[sav->alg_auth]);
1132 #ifdef REGRESSION
1133 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1134 if (V_ipsec_integrity) {
1135 int alen;
1136
1137 /*
1138 * Corrupt HMAC if we want to test integrity verification of
1139 * the other side.
1140 */
1141 alen = AUTHSIZE(sav);
1142 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1143 }
1144 #endif
1145
1146 /* NB: m is reclaimed by ipsec_process_done. */
1147 error = ipsec_process_done(m, sp, sav, idx);
1148 CURVNET_RESTORE();
1149 return (error);
1150 bad:
1151 CURVNET_RESTORE();
1152 free(xd, M_XDATA);
1153 crypto_freereq(crp);
1154 key_freesav(&sav);
1155 key_freesp(&sp);
1156 return (error);
1157 }
1158
1159 static struct xformsw ah_xformsw = {
1160 .xf_type = XF_AH,
1161 .xf_name = "IPsec AH",
1162 .xf_init = ah_init,
1163 .xf_zeroize = ah_zeroize,
1164 .xf_input = ah_input,
1165 .xf_output = ah_output,
1166 };
1167
1168 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1169 xform_attach, &ah_xformsw);
1170 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1171 xform_detach, &ah_xformsw);
Cache object: fe0239185ce995e4919c3c552318c6e0
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