1 /* $FreeBSD: releng/11.1/sys/netipsec/xform_ah.c 331985 2018-04-04 05:37:52Z gordon $ */
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;
151 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
152 /*XXX not right for null algorithm--does it matter??*/
153 authsize = AUTHSIZE(sav);
154 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
155 } else {
156 /* default guess */
157 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
158 }
159 return size;
160 }
161
162 /*
163 * NB: public for use by esp_init.
164 */
165 int
166 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
167 {
168 const struct auth_hash *thash;
169 int keylen;
170
171 thash = auth_algorithm_lookup(sav->alg_auth);
172 if (thash == NULL) {
173 DPRINTF(("%s: unsupported authentication algorithm %u\n",
174 __func__, sav->alg_auth));
175 return EINVAL;
176 }
177 /*
178 * Verify the replay state block allocation is consistent with
179 * the protocol type. We check here so we can make assumptions
180 * later during protocol processing.
181 */
182 /* NB: replay state is setup elsewhere (sigh) */
183 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
184 DPRINTF(("%s: replay state block inconsistency, "
185 "%s algorithm %s replay state\n", __func__,
186 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
187 sav->replay == NULL ? "without" : "with"));
188 return EINVAL;
189 }
190 if (sav->key_auth == NULL) {
191 DPRINTF(("%s: no authentication key for %s algorithm\n",
192 __func__, thash->name));
193 return EINVAL;
194 }
195 keylen = _KEYLEN(sav->key_auth);
196 if (keylen != thash->keysize && thash->keysize != 0) {
197 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
198 "keysize %d\n", __func__,
199 keylen, thash->name, thash->keysize));
200 return EINVAL;
201 }
202
203 sav->tdb_xform = xsp;
204 sav->tdb_authalgxform = thash;
205
206 /* Initialize crypto session. */
207 bzero(cria, sizeof (*cria));
208 cria->cri_alg = sav->tdb_authalgxform->type;
209 cria->cri_klen = _KEYBITS(sav->key_auth);
210 cria->cri_key = sav->key_auth->key_data;
211 cria->cri_mlen = AUTHSIZE(sav);
212
213 return 0;
214 }
215
216 /*
217 * ah_init() is called when an SPI is being set up.
218 */
219 static int
220 ah_init(struct secasvar *sav, struct xformsw *xsp)
221 {
222 struct cryptoini cria;
223 int error;
224
225 error = ah_init0(sav, xsp, &cria);
226 return error ? error :
227 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
228 }
229
230 /*
231 * Paranoia.
232 *
233 * NB: public for use by esp_zeroize (XXX).
234 */
235 int
236 ah_zeroize(struct secasvar *sav)
237 {
238 int err;
239
240 if (sav->key_auth)
241 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
242
243 err = crypto_freesession(sav->tdb_cryptoid);
244 sav->tdb_cryptoid = 0;
245 sav->tdb_authalgxform = NULL;
246 sav->tdb_xform = NULL;
247 return err;
248 }
249
250 /*
251 * Massage IPv4/IPv6 headers for AH processing.
252 */
253 static int
254 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
255 {
256 struct mbuf *m = *m0;
257 unsigned char *ptr;
258 int off, count;
259
260 #ifdef INET
261 struct ip *ip;
262 #endif /* INET */
263
264 #ifdef INET6
265 struct ip6_ext *ip6e;
266 struct ip6_hdr ip6;
267 int ad, alloc, nxt, noff;
268 #endif /* INET6 */
269
270 switch (proto) {
271 #ifdef INET
272 case AF_INET:
273 /*
274 * This is the least painful way of dealing with IPv4 header
275 * and option processing -- just make sure they're in
276 * contiguous memory.
277 */
278 *m0 = m = m_pullup(m, skip);
279 if (m == NULL) {
280 DPRINTF(("%s: m_pullup failed\n", __func__));
281 return ENOBUFS;
282 }
283
284 /* Fix the IP header */
285 ip = mtod(m, struct ip *);
286 if (V_ah_cleartos)
287 ip->ip_tos = 0;
288 ip->ip_ttl = 0;
289 ip->ip_sum = 0;
290
291 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
292 ip->ip_off &= htons(IP_DF);
293 else
294 ip->ip_off = htons(0);
295
296 ptr = mtod(m, unsigned char *);
297
298 /* IPv4 option processing */
299 for (off = sizeof(struct ip); off < skip;) {
300 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
301 off + 1 < skip)
302 ;
303 else {
304 DPRINTF(("%s: illegal IPv4 option length for "
305 "option %d\n", __func__, ptr[off]));
306
307 m_freem(m);
308 return EINVAL;
309 }
310
311 switch (ptr[off]) {
312 case IPOPT_EOL:
313 off = skip; /* End the loop. */
314 break;
315
316 case IPOPT_NOP:
317 off++;
318 break;
319
320 case IPOPT_SECURITY: /* 0x82 */
321 case 0x85: /* Extended security. */
322 case 0x86: /* Commercial security. */
323 case 0x94: /* Router alert */
324 case 0x95: /* RFC1770 */
325 /* Sanity check for option length. */
326 if (ptr[off + 1] < 2) {
327 DPRINTF(("%s: illegal IPv4 option "
328 "length for option %d\n",
329 __func__, ptr[off]));
330
331 m_freem(m);
332 return EINVAL;
333 }
334
335 off += ptr[off + 1];
336 break;
337
338 case IPOPT_LSRR:
339 case IPOPT_SSRR:
340 /* Sanity check for option length. */
341 if (ptr[off + 1] < 2) {
342 DPRINTF(("%s: illegal IPv4 option "
343 "length for option %d\n",
344 __func__, ptr[off]));
345
346 m_freem(m);
347 return EINVAL;
348 }
349
350 /*
351 * On output, if we have either of the
352 * source routing options, we should
353 * swap the destination address of the
354 * IP header with the last address
355 * specified in the option, as that is
356 * what the destination's IP header
357 * will look like.
358 */
359 if (out)
360 bcopy(ptr + off + ptr[off + 1] -
361 sizeof(struct in_addr),
362 &(ip->ip_dst), sizeof(struct in_addr));
363
364 /* Fall through */
365 default:
366 /* Sanity check for option length. */
367 if (ptr[off + 1] < 2) {
368 DPRINTF(("%s: illegal IPv4 option "
369 "length for option %d\n",
370 __func__, ptr[off]));
371 m_freem(m);
372 return EINVAL;
373 }
374
375 /* Zeroize all other options. */
376 count = ptr[off + 1];
377 bcopy(ipseczeroes, ptr + off, count);
378 off += count;
379 break;
380 }
381
382 /* Sanity check. */
383 if (off > skip) {
384 DPRINTF(("%s: malformed IPv4 options header\n",
385 __func__));
386
387 m_freem(m);
388 return EINVAL;
389 }
390 }
391
392 break;
393 #endif /* INET */
394
395 #ifdef INET6
396 case AF_INET6: /* Ugly... */
397 /* Copy and "cook" the IPv6 header. */
398 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
399
400 /* We don't do IPv6 Jumbograms. */
401 if (ip6.ip6_plen == 0) {
402 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
403 m_freem(m);
404 return EMSGSIZE;
405 }
406
407 ip6.ip6_flow = 0;
408 ip6.ip6_hlim = 0;
409 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
410 ip6.ip6_vfc |= IPV6_VERSION;
411
412 /* Scoped address handling. */
413 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
414 ip6.ip6_src.s6_addr16[1] = 0;
415 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
416 ip6.ip6_dst.s6_addr16[1] = 0;
417
418 /* Done with IPv6 header. */
419 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
420
421 /* Let's deal with the remaining headers (if any). */
422 if (skip - sizeof(struct ip6_hdr) > 0) {
423 if (m->m_len <= skip) {
424 ptr = (unsigned char *) malloc(
425 skip - sizeof(struct ip6_hdr),
426 M_XDATA, M_NOWAIT);
427 if (ptr == NULL) {
428 DPRINTF(("%s: failed to allocate memory"
429 "for IPv6 headers\n",__func__));
430 m_freem(m);
431 return ENOBUFS;
432 }
433
434 /*
435 * Copy all the protocol headers after
436 * the IPv6 header.
437 */
438 m_copydata(m, sizeof(struct ip6_hdr),
439 skip - sizeof(struct ip6_hdr), ptr);
440 alloc = 1;
441 } else {
442 /* No need to allocate memory. */
443 ptr = mtod(m, unsigned char *) +
444 sizeof(struct ip6_hdr);
445 alloc = 0;
446 }
447 } else
448 break;
449
450 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
451
452 for (off = 0; off < skip - sizeof(struct ip6_hdr);)
453 switch (nxt) {
454 case IPPROTO_HOPOPTS:
455 case IPPROTO_DSTOPTS:
456 ip6e = (struct ip6_ext *)(ptr + off);
457 noff = off + ((ip6e->ip6e_len + 1) << 3);
458
459 /* Sanity check. */
460 if (noff > skip - sizeof(struct ip6_hdr))
461 goto error6;
462
463 /*
464 * Zero out mutable options.
465 */
466 for (count = off + sizeof(struct ip6_ext);
467 count < noff;) {
468 if (ptr[count] == IP6OPT_PAD1) {
469 count++;
470 continue; /* Skip padding. */
471 }
472
473 ad = ptr[count + 1] + 2;
474 if (count + ad > noff)
475 goto error6;
476
477 if (ptr[count] & IP6OPT_MUTABLE)
478 memset(ptr + count, 0, ad);
479 count += ad;
480 }
481
482 if (count != noff)
483 goto error6;
484
485 /* Advance. */
486 off += ((ip6e->ip6e_len + 1) << 3);
487 nxt = ip6e->ip6e_nxt;
488 break;
489
490 case IPPROTO_ROUTING:
491 /*
492 * Always include routing headers in
493 * computation.
494 */
495 ip6e = (struct ip6_ext *) (ptr + off);
496 off += ((ip6e->ip6e_len + 1) << 3);
497 nxt = ip6e->ip6e_nxt;
498 break;
499
500 default:
501 DPRINTF(("%s: unexpected IPv6 header type %d",
502 __func__, off));
503 error6:
504 if (alloc)
505 free(ptr, M_XDATA);
506 m_freem(m);
507 return EINVAL;
508 }
509
510 /* Copyback and free, if we allocated. */
511 if (alloc) {
512 m_copyback(m, sizeof(struct ip6_hdr),
513 skip - sizeof(struct ip6_hdr), ptr);
514 free(ptr, M_XDATA);
515 }
516
517 break;
518 #endif /* INET6 */
519 }
520
521 return 0;
522 }
523
524 /*
525 * ah_input() gets called to verify that an input packet
526 * passes authentication.
527 */
528 static int
529 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
530 {
531 IPSEC_DEBUG_DECLARE(char buf[128]);
532 const struct auth_hash *ahx;
533 struct cryptodesc *crda;
534 struct cryptop *crp;
535 struct xform_data *xd;
536 struct newah *ah;
537 uint64_t cryptoid;
538 int hl, rplen, authsize, error;
539
540 IPSEC_ASSERT(sav != NULL, ("null SA"));
541 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
542 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
543 ("null authentication xform"));
544
545 /* Figure out header size. */
546 rplen = HDRSIZE(sav);
547
548 /* XXX don't pullup, just copy header */
549 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
550 if (ah == NULL) {
551 DPRINTF(("ah_input: cannot pullup header\n"));
552 AHSTAT_INC(ahs_hdrops); /*XXX*/
553 error = ENOBUFS;
554 goto bad;
555 }
556
557 /* Check replay window, if applicable. */
558 SECASVAR_LOCK(sav);
559 if (sav->replay != NULL && sav->replay->wsize != 0 &&
560 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) {
561 SECASVAR_UNLOCK(sav);
562 AHSTAT_INC(ahs_replay);
563 DPRINTF(("%s: packet replay failure: %s\n", __func__,
564 ipsec_sa2str(sav, buf, sizeof(buf))));
565 error = EACCES;
566 goto bad;
567 }
568 cryptoid = sav->tdb_cryptoid;
569 SECASVAR_UNLOCK(sav);
570
571 /* Verify AH header length. */
572 hl = ah->ah_len * sizeof (u_int32_t);
573 ahx = sav->tdb_authalgxform;
574 authsize = AUTHSIZE(sav);
575 if (hl != authsize + rplen - sizeof (struct ah)) {
576 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
577 " for packet in SA %s/%08lx\n", __func__, hl,
578 (u_long) (authsize + rplen - sizeof (struct ah)),
579 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
580 (u_long) ntohl(sav->spi)));
581 AHSTAT_INC(ahs_badauthl);
582 error = EACCES;
583 goto bad;
584 }
585 if (skip + authsize + rplen > m->m_pkthdr.len) {
586 DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
587 " for packet in SA %s/%08lx\n", __func__,
588 m->m_pkthdr.len, (u_long) (skip + authsize + rplen),
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 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
596
597 /* Get crypto descriptors. */
598 crp = crypto_getreq(1);
599 if (crp == NULL) {
600 DPRINTF(("%s: failed to acquire crypto descriptor\n",
601 __func__));
602 AHSTAT_INC(ahs_crypto);
603 error = ENOBUFS;
604 goto bad;
605 }
606
607 crda = crp->crp_desc;
608 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
609
610 crda->crd_skip = 0;
611 crda->crd_len = m->m_pkthdr.len;
612 crda->crd_inject = skip + rplen;
613
614 /* Authentication operation. */
615 crda->crd_alg = ahx->type;
616 crda->crd_klen = _KEYBITS(sav->key_auth);
617 crda->crd_key = sav->key_auth->key_data;
618
619 /* Allocate IPsec-specific opaque crypto info. */
620 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA,
621 M_NOWAIT | M_ZERO);
622 if (xd == NULL) {
623 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
624 AHSTAT_INC(ahs_crypto);
625 crypto_freereq(crp);
626 error = ENOBUFS;
627 goto bad;
628 }
629
630 /*
631 * Save the authenticator, the skipped portion of the packet,
632 * and the AH header.
633 */
634 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1));
635
636 /* Zeroize the authenticator on the packet. */
637 m_copyback(m, skip + rplen, authsize, ipseczeroes);
638
639 /* Save ah_nxt, since ah pointer can become invalid after "massage" */
640 hl = ah->ah_nxt;
641
642 /* "Massage" the packet headers for crypto processing. */
643 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
644 skip, ahx->type, 0);
645 if (error != 0) {
646 /* NB: mbuf is free'd by ah_massage_headers */
647 AHSTAT_INC(ahs_hdrops);
648 free(xd, M_XDATA);
649 crypto_freereq(crp);
650 key_freesav(&sav);
651 return (error);
652 }
653
654 /* Crypto operation descriptor. */
655 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
656 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
657 crp->crp_buf = (caddr_t) m;
658 crp->crp_callback = ah_input_cb;
659 crp->crp_sid = cryptoid;
660 crp->crp_opaque = (caddr_t) xd;
661
662 /* These are passed as-is to the callback. */
663 xd->sav = sav;
664 xd->nxt = hl;
665 xd->protoff = protoff;
666 xd->skip = skip;
667 xd->cryptoid = cryptoid;
668 return (crypto_dispatch(crp));
669 bad:
670 m_freem(m);
671 key_freesav(&sav);
672 return (error);
673 }
674
675 /*
676 * AH input callback from the crypto driver.
677 */
678 static int
679 ah_input_cb(struct cryptop *crp)
680 {
681 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
682 unsigned char calc[AH_ALEN_MAX];
683 const struct auth_hash *ahx;
684 struct mbuf *m;
685 struct cryptodesc *crd;
686 struct xform_data *xd;
687 struct secasvar *sav;
688 struct secasindex *saidx;
689 caddr_t ptr;
690 uint64_t cryptoid;
691 int authsize, rplen, error, skip, protoff;
692 uint8_t nxt;
693
694 crd = crp->crp_desc;
695 m = (struct mbuf *) crp->crp_buf;
696 xd = (struct xform_data *) crp->crp_opaque;
697 sav = xd->sav;
698 skip = xd->skip;
699 nxt = xd->nxt;
700 protoff = xd->protoff;
701 cryptoid = xd->cryptoid;
702 saidx = &sav->sah->saidx;
703 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
704 saidx->dst.sa.sa_family == AF_INET6,
705 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
706
707 ahx = sav->tdb_authalgxform;
708
709 /* Check for crypto errors. */
710 if (crp->crp_etype) {
711 if (crp->crp_etype == EAGAIN) {
712 /* Reset the session ID */
713 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
714 crypto_freesession(cryptoid);
715 xd->cryptoid = crp->crp_sid;
716 return (crypto_dispatch(crp));
717 }
718 AHSTAT_INC(ahs_noxform);
719 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
720 error = crp->crp_etype;
721 goto bad;
722 } else {
723 AHSTAT_INC(ahs_hist[sav->alg_auth]);
724 crypto_freereq(crp); /* No longer needed. */
725 crp = NULL;
726 }
727
728 /* Shouldn't happen... */
729 if (m == NULL) {
730 AHSTAT_INC(ahs_crypto);
731 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
732 error = EINVAL;
733 goto bad;
734 }
735
736 /* Figure out header size. */
737 rplen = HDRSIZE(sav);
738 authsize = AUTHSIZE(sav);
739
740 /* Copy authenticator off the packet. */
741 m_copydata(m, skip + rplen, authsize, calc);
742
743 /* Verify authenticator. */
744 ptr = (caddr_t) (xd + 1);
745 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
746 DPRINTF(("%s: authentication hash mismatch for packet "
747 "in SA %s/%08lx\n", __func__,
748 ipsec_address(&saidx->dst, buf, sizeof(buf)),
749 (u_long) ntohl(sav->spi)));
750 AHSTAT_INC(ahs_badauth);
751 error = EACCES;
752 goto bad;
753 }
754 /* Fix the Next Protocol field. */
755 ((uint8_t *) ptr)[protoff] = nxt;
756
757 /* Copyback the saved (uncooked) network headers. */
758 m_copyback(m, 0, skip, ptr);
759 free(xd, M_XDATA), xd = NULL; /* No longer needed */
760
761 /*
762 * Header is now authenticated.
763 */
764 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
765
766 /*
767 * Update replay sequence number, if appropriate.
768 */
769 if (sav->replay) {
770 u_int32_t seq;
771
772 m_copydata(m, skip + offsetof(struct newah, ah_seq),
773 sizeof (seq), (caddr_t) &seq);
774 SECASVAR_LOCK(sav);
775 if (ipsec_updatereplay(ntohl(seq), sav)) {
776 SECASVAR_UNLOCK(sav);
777 AHSTAT_INC(ahs_replay);
778 error = EACCES;
779 goto bad;
780 }
781 SECASVAR_UNLOCK(sav);
782 }
783
784 /*
785 * Remove the AH header and authenticator from the mbuf.
786 */
787 error = m_striphdr(m, skip, rplen + authsize);
788 if (error) {
789 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
790 ipsec_address(&saidx->dst, buf, sizeof(buf)),
791 (u_long) ntohl(sav->spi)));
792 AHSTAT_INC(ahs_hdrops);
793 goto bad;
794 }
795
796 switch (saidx->dst.sa.sa_family) {
797 #ifdef INET6
798 case AF_INET6:
799 error = ipsec6_common_input_cb(m, sav, skip, protoff);
800 break;
801 #endif
802 #ifdef INET
803 case AF_INET:
804 error = ipsec4_common_input_cb(m, sav, skip, protoff);
805 break;
806 #endif
807 default:
808 panic("%s: Unexpected address family: %d saidx=%p", __func__,
809 saidx->dst.sa.sa_family, saidx);
810 }
811 return error;
812 bad:
813 if (sav)
814 key_freesav(&sav);
815 if (m != NULL)
816 m_freem(m);
817 if (xd != NULL)
818 free(xd, M_XDATA);
819 if (crp != NULL)
820 crypto_freereq(crp);
821 return error;
822 }
823
824 /*
825 * AH output routine, called by ipsec[46]_perform_request().
826 */
827 static int
828 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
829 u_int idx, int skip, int protoff)
830 {
831 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
832 const struct auth_hash *ahx;
833 struct cryptodesc *crda;
834 struct xform_data *xd;
835 struct mbuf *mi;
836 struct cryptop *crp;
837 struct newah *ah;
838 uint64_t cryptoid;
839 uint16_t iplen;
840 int error, rplen, authsize, maxpacketsize, roff;
841 uint8_t prot;
842
843 IPSEC_ASSERT(sav != NULL, ("null SA"));
844 ahx = sav->tdb_authalgxform;
845 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
846
847 AHSTAT_INC(ahs_output);
848
849 /* Figure out header size. */
850 rplen = HDRSIZE(sav);
851
852 /* Check for maximum packet size violations. */
853 switch (sav->sah->saidx.dst.sa.sa_family) {
854 #ifdef INET
855 case AF_INET:
856 maxpacketsize = IP_MAXPACKET;
857 break;
858 #endif /* INET */
859 #ifdef INET6
860 case AF_INET6:
861 maxpacketsize = IPV6_MAXPACKET;
862 break;
863 #endif /* INET6 */
864 default:
865 DPRINTF(("%s: unknown/unsupported protocol family %u, "
866 "SA %s/%08lx\n", __func__,
867 sav->sah->saidx.dst.sa.sa_family,
868 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
869 (u_long) ntohl(sav->spi)));
870 AHSTAT_INC(ahs_nopf);
871 error = EPFNOSUPPORT;
872 goto bad;
873 }
874 authsize = AUTHSIZE(sav);
875 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
876 DPRINTF(("%s: packet in SA %s/%08lx got too big "
877 "(len %u, max len %u)\n", __func__,
878 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
879 (u_long) ntohl(sav->spi),
880 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
881 AHSTAT_INC(ahs_toobig);
882 error = EMSGSIZE;
883 goto bad;
884 }
885
886 /* Update the counters. */
887 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
888
889 m = m_unshare(m, M_NOWAIT);
890 if (m == NULL) {
891 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
892 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
893 (u_long) ntohl(sav->spi)));
894 AHSTAT_INC(ahs_hdrops);
895 error = ENOBUFS;
896 goto bad;
897 }
898
899 /* Inject AH header. */
900 mi = m_makespace(m, skip, rplen + authsize, &roff);
901 if (mi == NULL) {
902 DPRINTF(("%s: failed to inject %u byte AH header for SA "
903 "%s/%08lx\n", __func__,
904 rplen + authsize,
905 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
906 (u_long) ntohl(sav->spi)));
907 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
908 error = ENOBUFS;
909 goto bad;
910 }
911
912 /*
913 * The AH header is guaranteed by m_makespace() to be in
914 * contiguous memory, at roff bytes offset into the returned mbuf.
915 */
916 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
917
918 /* Initialize the AH header. */
919 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
920 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
921 ah->ah_reserve = 0;
922 ah->ah_spi = sav->spi;
923
924 /* Zeroize authenticator. */
925 m_copyback(m, skip + rplen, authsize, ipseczeroes);
926
927 /* Insert packet replay counter, as requested. */
928 SECASVAR_LOCK(sav);
929 if (sav->replay) {
930 if (sav->replay->count == ~0 &&
931 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
932 SECASVAR_UNLOCK(sav);
933 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
934 __func__, ipsec_address(&sav->sah->saidx.dst, buf,
935 sizeof(buf)), (u_long) ntohl(sav->spi)));
936 AHSTAT_INC(ahs_wrap);
937 error = EACCES;
938 goto bad;
939 }
940 #ifdef REGRESSION
941 /* Emulate replay attack when ipsec_replay is TRUE. */
942 if (!V_ipsec_replay)
943 #endif
944 sav->replay->count++;
945 ah->ah_seq = htonl(sav->replay->count);
946 }
947 cryptoid = sav->tdb_cryptoid;
948 SECASVAR_UNLOCK(sav);
949
950 /* Get crypto descriptors. */
951 crp = crypto_getreq(1);
952 if (crp == NULL) {
953 DPRINTF(("%s: failed to acquire crypto descriptors\n",
954 __func__));
955 AHSTAT_INC(ahs_crypto);
956 error = ENOBUFS;
957 goto bad;
958 }
959
960 crda = crp->crp_desc;
961 crda->crd_skip = 0;
962 crda->crd_inject = skip + rplen;
963 crda->crd_len = m->m_pkthdr.len;
964
965 /* Authentication operation. */
966 crda->crd_alg = ahx->type;
967 crda->crd_key = sav->key_auth->key_data;
968 crda->crd_klen = _KEYBITS(sav->key_auth);
969
970 /* Allocate IPsec-specific opaque crypto info. */
971 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA,
972 M_NOWAIT | M_ZERO);
973 if (xd == NULL) {
974 crypto_freereq(crp);
975 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
976 AHSTAT_INC(ahs_crypto);
977 error = ENOBUFS;
978 goto bad;
979 }
980
981 /* Save the skipped portion of the packet. */
982 m_copydata(m, 0, skip, (caddr_t) (xd + 1));
983
984 /*
985 * Fix IP header length on the header used for
986 * authentication. We don't need to fix the original
987 * header length as it will be fixed by our caller.
988 */
989 switch (sav->sah->saidx.dst.sa.sa_family) {
990 #ifdef INET
991 case AF_INET:
992 bcopy(((caddr_t)(xd + 1)) +
993 offsetof(struct ip, ip_len),
994 (caddr_t) &iplen, sizeof(u_int16_t));
995 iplen = htons(ntohs(iplen) + rplen + authsize);
996 m_copyback(m, offsetof(struct ip, ip_len),
997 sizeof(u_int16_t), (caddr_t) &iplen);
998 break;
999 #endif /* INET */
1000
1001 #ifdef INET6
1002 case AF_INET6:
1003 bcopy(((caddr_t)(xd + 1)) +
1004 offsetof(struct ip6_hdr, ip6_plen),
1005 (caddr_t) &iplen, sizeof(uint16_t));
1006 iplen = htons(ntohs(iplen) + rplen + authsize);
1007 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1008 sizeof(uint16_t), (caddr_t) &iplen);
1009 break;
1010 #endif /* INET6 */
1011 }
1012
1013 /* Fix the Next Header field in saved header. */
1014 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH;
1015
1016 /* Update the Next Protocol field in the IP header. */
1017 prot = IPPROTO_AH;
1018 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot);
1019
1020 /* "Massage" the packet headers for crypto processing. */
1021 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1022 skip, ahx->type, 1);
1023 if (error != 0) {
1024 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1025 free(xd, M_XDATA);
1026 crypto_freereq(crp);
1027 goto bad;
1028 }
1029
1030 /* Crypto operation descriptor. */
1031 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1032 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1033 crp->crp_buf = (caddr_t) m;
1034 crp->crp_callback = ah_output_cb;
1035 crp->crp_sid = cryptoid;
1036 crp->crp_opaque = (caddr_t) xd;
1037
1038 /* These are passed as-is to the callback. */
1039 xd->sp = sp;
1040 xd->sav = sav;
1041 xd->skip = skip;
1042 xd->idx = idx;
1043 xd->cryptoid = cryptoid;
1044
1045 return crypto_dispatch(crp);
1046 bad:
1047 if (m)
1048 m_freem(m);
1049 key_freesav(&sav);
1050 key_freesp(&sp);
1051 return (error);
1052 }
1053
1054 /*
1055 * AH output callback from the crypto driver.
1056 */
1057 static int
1058 ah_output_cb(struct cryptop *crp)
1059 {
1060 struct xform_data *xd;
1061 struct secpolicy *sp;
1062 struct secasvar *sav;
1063 struct mbuf *m;
1064 uint64_t cryptoid;
1065 caddr_t ptr;
1066 u_int idx;
1067 int skip, error;
1068
1069 m = (struct mbuf *) crp->crp_buf;
1070 xd = (struct xform_data *) crp->crp_opaque;
1071 sp = xd->sp;
1072 sav = xd->sav;
1073 skip = xd->skip;
1074 idx = xd->idx;
1075 cryptoid = xd->cryptoid;
1076 ptr = (caddr_t) (xd + 1);
1077
1078 /* Check for crypto errors. */
1079 if (crp->crp_etype) {
1080 if (crp->crp_etype == EAGAIN) {
1081 /* Reset the session ID */
1082 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
1083 crypto_freesession(cryptoid);
1084 xd->cryptoid = crp->crp_sid;
1085 return (crypto_dispatch(crp));
1086 }
1087 AHSTAT_INC(ahs_noxform);
1088 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1089 error = crp->crp_etype;
1090 m_freem(m);
1091 goto bad;
1092 }
1093
1094 /* Shouldn't happen... */
1095 if (m == NULL) {
1096 AHSTAT_INC(ahs_crypto);
1097 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1098 error = EINVAL;
1099 goto bad;
1100 }
1101 /*
1102 * Copy original headers (with the new protocol number) back
1103 * in place.
1104 */
1105 m_copyback(m, 0, skip, ptr);
1106
1107 free(xd, M_XDATA);
1108 crypto_freereq(crp);
1109 AHSTAT_INC(ahs_hist[sav->alg_auth]);
1110 #ifdef REGRESSION
1111 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1112 if (V_ipsec_integrity) {
1113 int alen;
1114
1115 /*
1116 * Corrupt HMAC if we want to test integrity verification of
1117 * the other side.
1118 */
1119 alen = AUTHSIZE(sav);
1120 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1121 }
1122 #endif
1123
1124 /* NB: m is reclaimed by ipsec_process_done. */
1125 error = ipsec_process_done(m, sp, sav, idx);
1126 return (error);
1127 bad:
1128 free(xd, M_XDATA);
1129 crypto_freereq(crp);
1130 key_freesav(&sav);
1131 key_freesp(&sp);
1132 return (error);
1133 }
1134
1135 static struct xformsw ah_xformsw = {
1136 .xf_type = XF_AH,
1137 .xf_name = "IPsec AH",
1138 .xf_init = ah_init,
1139 .xf_zeroize = ah_zeroize,
1140 .xf_input = ah_input,
1141 .xf_output = ah_output,
1142 };
1143
1144 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1145 xform_attach, &ah_xformsw);
1146 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1147 xform_detach, &ah_xformsw);
Cache object: 40e16f2797bb90afacfeee528b5e7e48
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