1 /* $FreeBSD: stable/10/sys/netipsec/xform_ah.c 330609 2018-03-07 16:55:15Z 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/sysctl.h>
49
50 #include <net/if.h>
51 #include <net/vnet.h>
52
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_ecn.h>
57 #include <netinet/ip6.h>
58
59 #include <netipsec/ipsec.h>
60 #include <netipsec/ah.h>
61 #include <netipsec/ah_var.h>
62 #include <netipsec/xform.h>
63
64 #ifdef INET6
65 #include <netinet6/ip6_var.h>
66 #include <netipsec/ipsec6.h>
67 #include <netinet6/ip6_ecn.h>
68 #endif
69
70 #include <netipsec/key.h>
71 #include <netipsec/key_debug.h>
72
73 #include <opencrypto/cryptodev.h>
74
75 /*
76 * Return header size in bytes. The old protocol did not support
77 * the replay counter; the new protocol always includes the counter.
78 */
79 #define HDRSIZE(sav) \
80 (((sav)->flags & SADB_X_EXT_OLD) ? \
81 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
82 /*
83 * Return authenticator size in bytes. The old protocol is known
84 * to use a fixed 16-byte authenticator. The new algorithm use 12-byte
85 * authenticator.
86 */
87 #define AUTHSIZE(sav) ah_authsize(sav)
88
89 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
90 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
91 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat);
92 VNET_PCPUSTAT_SYSINIT(ahstat);
93
94 #ifdef VIMAGE
95 VNET_PCPUSTAT_SYSUNINIT(ahstat);
96 #endif /* VIMAGE */
97
98 #ifdef INET
99 SYSCTL_DECL(_net_inet_ah);
100 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO,
101 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
102 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO,
103 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
104 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat,
105 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)");
106 #endif
107
108 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
109
110 static int ah_input_cb(struct cryptop*);
111 static int ah_output_cb(struct cryptop*);
112
113 static int
ah_authsize(struct secasvar * sav)114 ah_authsize(struct secasvar *sav)
115 {
116
117 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__));
118
119 if (sav->flags & SADB_X_EXT_OLD)
120 return 16;
121
122 switch (sav->alg_auth) {
123 case SADB_X_AALG_SHA2_256:
124 return 16;
125 case SADB_X_AALG_SHA2_384:
126 return 24;
127 case SADB_X_AALG_SHA2_512:
128 return 32;
129 default:
130 return AH_HMAC_HASHLEN;
131 }
132 /* NOTREACHED */
133 }
134 /*
135 * NB: this is public for use by the PF_KEY support.
136 */
137 struct auth_hash *
ah_algorithm_lookup(int alg)138 ah_algorithm_lookup(int alg)
139 {
140 if (alg > SADB_AALG_MAX)
141 return NULL;
142 switch (alg) {
143 case SADB_X_AALG_NULL:
144 return &auth_hash_null;
145 case SADB_AALG_MD5HMAC:
146 return &auth_hash_hmac_md5;
147 case SADB_AALG_SHA1HMAC:
148 return &auth_hash_hmac_sha1;
149 case SADB_X_AALG_RIPEMD160HMAC:
150 return &auth_hash_hmac_ripemd_160;
151 case SADB_X_AALG_MD5:
152 return &auth_hash_key_md5;
153 case SADB_X_AALG_SHA:
154 return &auth_hash_key_sha1;
155 case SADB_X_AALG_SHA2_256:
156 return &auth_hash_hmac_sha2_256;
157 case SADB_X_AALG_SHA2_384:
158 return &auth_hash_hmac_sha2_384;
159 case SADB_X_AALG_SHA2_512:
160 return &auth_hash_hmac_sha2_512;
161 }
162 return NULL;
163 }
164
165 size_t
ah_hdrsiz(struct secasvar * sav)166 ah_hdrsiz(struct secasvar *sav)
167 {
168 size_t size;
169
170 if (sav != NULL) {
171 int authsize;
172 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
173 /*XXX not right for null algorithm--does it matter??*/
174 authsize = AUTHSIZE(sav);
175 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
176 } else {
177 /* default guess */
178 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
179 }
180 return size;
181 }
182
183 /*
184 * NB: public for use by esp_init.
185 */
186 int
ah_init0(struct secasvar * sav,struct xformsw * xsp,struct cryptoini * cria)187 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
188 {
189 struct auth_hash *thash;
190 int keylen;
191
192 thash = ah_algorithm_lookup(sav->alg_auth);
193 if (thash == NULL) {
194 DPRINTF(("%s: unsupported authentication algorithm %u\n",
195 __func__, sav->alg_auth));
196 return EINVAL;
197 }
198 /*
199 * Verify the replay state block allocation is consistent with
200 * the protocol type. We check here so we can make assumptions
201 * later during protocol processing.
202 */
203 /* NB: replay state is setup elsewhere (sigh) */
204 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
205 DPRINTF(("%s: replay state block inconsistency, "
206 "%s algorithm %s replay state\n", __func__,
207 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
208 sav->replay == NULL ? "without" : "with"));
209 return EINVAL;
210 }
211 if (sav->key_auth == NULL) {
212 DPRINTF(("%s: no authentication key for %s algorithm\n",
213 __func__, thash->name));
214 return EINVAL;
215 }
216 keylen = _KEYLEN(sav->key_auth);
217 if (keylen != thash->keysize && thash->keysize != 0) {
218 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
219 "keysize %d\n", __func__,
220 keylen, thash->name, thash->keysize));
221 return EINVAL;
222 }
223
224 sav->tdb_xform = xsp;
225 sav->tdb_authalgxform = thash;
226
227 /* Initialize crypto session. */
228 bzero(cria, sizeof (*cria));
229 cria->cri_alg = sav->tdb_authalgxform->type;
230 cria->cri_klen = _KEYBITS(sav->key_auth);
231 cria->cri_key = sav->key_auth->key_data;
232 cria->cri_mlen = AUTHSIZE(sav);
233
234 return 0;
235 }
236
237 /*
238 * ah_init() is called when an SPI is being set up.
239 */
240 static int
ah_init(struct secasvar * sav,struct xformsw * xsp)241 ah_init(struct secasvar *sav, struct xformsw *xsp)
242 {
243 struct cryptoini cria;
244 int error;
245
246 error = ah_init0(sav, xsp, &cria);
247 return error ? error :
248 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
249 }
250
251 /*
252 * Paranoia.
253 *
254 * NB: public for use by esp_zeroize (XXX).
255 */
256 int
ah_zeroize(struct secasvar * sav)257 ah_zeroize(struct secasvar *sav)
258 {
259 int err;
260
261 if (sav->key_auth)
262 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
263
264 err = crypto_freesession(sav->tdb_cryptoid);
265 sav->tdb_cryptoid = 0;
266 sav->tdb_authalgxform = NULL;
267 sav->tdb_xform = NULL;
268 return err;
269 }
270
271 /*
272 * Massage IPv4/IPv6 headers for AH processing.
273 */
274 static int
ah_massage_headers(struct mbuf ** m0,int proto,int skip,int alg,int out)275 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
276 {
277 struct mbuf *m = *m0;
278 unsigned char *ptr;
279 int off, count;
280
281 #ifdef INET
282 struct ip *ip;
283 #endif /* INET */
284
285 #ifdef INET6
286 struct ip6_ext *ip6e;
287 struct ip6_hdr ip6;
288 int ad, alloc, nxt, noff;
289 #endif /* INET6 */
290
291 switch (proto) {
292 #ifdef INET
293 case AF_INET:
294 /*
295 * This is the least painful way of dealing with IPv4 header
296 * and option processing -- just make sure they're in
297 * contiguous memory.
298 */
299 *m0 = m = m_pullup(m, skip);
300 if (m == NULL) {
301 DPRINTF(("%s: m_pullup failed\n", __func__));
302 return ENOBUFS;
303 }
304
305 /* Fix the IP header */
306 ip = mtod(m, struct ip *);
307 if (V_ah_cleartos)
308 ip->ip_tos = 0;
309 ip->ip_ttl = 0;
310 ip->ip_sum = 0;
311
312 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
313 ip->ip_off &= htons(IP_DF);
314 else
315 ip->ip_off = htons(0);
316
317 ptr = mtod(m, unsigned char *);
318
319 /* IPv4 option processing */
320 for (off = sizeof(struct ip); off < skip;) {
321 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
322 off + 1 < skip)
323 ;
324 else {
325 DPRINTF(("%s: illegal IPv4 option length for "
326 "option %d\n", __func__, ptr[off]));
327
328 m_freem(m);
329 return EINVAL;
330 }
331
332 switch (ptr[off]) {
333 case IPOPT_EOL:
334 off = skip; /* End the loop. */
335 break;
336
337 case IPOPT_NOP:
338 off++;
339 break;
340
341 case IPOPT_SECURITY: /* 0x82 */
342 case 0x85: /* Extended security. */
343 case 0x86: /* Commercial security. */
344 case 0x94: /* Router alert */
345 case 0x95: /* RFC1770 */
346 /* Sanity check for option length. */
347 if (ptr[off + 1] < 2) {
348 DPRINTF(("%s: illegal IPv4 option "
349 "length for option %d\n",
350 __func__, ptr[off]));
351
352 m_freem(m);
353 return EINVAL;
354 }
355
356 off += ptr[off + 1];
357 break;
358
359 case IPOPT_LSRR:
360 case IPOPT_SSRR:
361 /* Sanity check for option length. */
362 if (ptr[off + 1] < 2) {
363 DPRINTF(("%s: illegal IPv4 option "
364 "length for option %d\n",
365 __func__, ptr[off]));
366
367 m_freem(m);
368 return EINVAL;
369 }
370
371 /*
372 * On output, if we have either of the
373 * source routing options, we should
374 * swap the destination address of the
375 * IP header with the last address
376 * specified in the option, as that is
377 * what the destination's IP header
378 * will look like.
379 */
380 if (out)
381 bcopy(ptr + off + ptr[off + 1] -
382 sizeof(struct in_addr),
383 &(ip->ip_dst), sizeof(struct in_addr));
384
385 /* Fall through */
386 default:
387 /* Sanity check for option length. */
388 if (ptr[off + 1] < 2) {
389 DPRINTF(("%s: illegal IPv4 option "
390 "length for option %d\n",
391 __func__, ptr[off]));
392 m_freem(m);
393 return EINVAL;
394 }
395
396 /* Zeroize all other options. */
397 count = ptr[off + 1];
398 bcopy(ipseczeroes, ptr + off, count);
399 off += count;
400 break;
401 }
402
403 /* Sanity check. */
404 if (off > skip) {
405 DPRINTF(("%s: malformed IPv4 options header\n",
406 __func__));
407
408 m_freem(m);
409 return EINVAL;
410 }
411 }
412
413 break;
414 #endif /* INET */
415
416 #ifdef INET6
417 case AF_INET6: /* Ugly... */
418 /* Copy and "cook" the IPv6 header. */
419 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
420
421 /* We don't do IPv6 Jumbograms. */
422 if (ip6.ip6_plen == 0) {
423 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
424 m_freem(m);
425 return EMSGSIZE;
426 }
427
428 ip6.ip6_flow = 0;
429 ip6.ip6_hlim = 0;
430 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
431 ip6.ip6_vfc |= IPV6_VERSION;
432
433 /* Scoped address handling. */
434 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
435 ip6.ip6_src.s6_addr16[1] = 0;
436 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
437 ip6.ip6_dst.s6_addr16[1] = 0;
438
439 /* Done with IPv6 header. */
440 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
441
442 /* Let's deal with the remaining headers (if any). */
443 if (skip - sizeof(struct ip6_hdr) > 0) {
444 if (m->m_len <= skip) {
445 ptr = (unsigned char *) malloc(
446 skip - sizeof(struct ip6_hdr),
447 M_XDATA, M_NOWAIT);
448 if (ptr == NULL) {
449 DPRINTF(("%s: failed to allocate memory"
450 "for IPv6 headers\n",__func__));
451 m_freem(m);
452 return ENOBUFS;
453 }
454
455 /*
456 * Copy all the protocol headers after
457 * the IPv6 header.
458 */
459 m_copydata(m, sizeof(struct ip6_hdr),
460 skip - sizeof(struct ip6_hdr), ptr);
461 alloc = 1;
462 } else {
463 /* No need to allocate memory. */
464 ptr = mtod(m, unsigned char *) +
465 sizeof(struct ip6_hdr);
466 alloc = 0;
467 }
468 } else
469 break;
470
471 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
472
473 for (off = 0; off < skip - sizeof(struct ip6_hdr);)
474 switch (nxt) {
475 case IPPROTO_HOPOPTS:
476 case IPPROTO_DSTOPTS:
477 ip6e = (struct ip6_ext *)(ptr + off);
478 noff = off + ((ip6e->ip6e_len + 1) << 3);
479
480 /* Sanity check. */
481 if (noff > skip - sizeof(struct ip6_hdr))
482 goto error6;
483
484 /*
485 * Zero out mutable options.
486 */
487 for (count = off + sizeof(struct ip6_ext);
488 count < noff;) {
489 if (ptr[count] == IP6OPT_PAD1) {
490 count++;
491 continue; /* Skip padding. */
492 }
493
494 ad = ptr[count + 1] + 2;
495 if (count + ad > noff)
496 goto error6;
497
498 if (ptr[count] & IP6OPT_MUTABLE)
499 memset(ptr + count, 0, ad);
500 count += ad;
501 }
502
503 if (count != noff)
504 goto error6;
505
506 /* Advance. */
507 off += ((ip6e->ip6e_len + 1) << 3);
508 nxt = ip6e->ip6e_nxt;
509 break;
510
511 case IPPROTO_ROUTING:
512 /*
513 * Always include routing headers in
514 * computation.
515 */
516 ip6e = (struct ip6_ext *) (ptr + off);
517 off += ((ip6e->ip6e_len + 1) << 3);
518 nxt = ip6e->ip6e_nxt;
519 break;
520
521 default:
522 DPRINTF(("%s: unexpected IPv6 header type %d",
523 __func__, off));
524 error6:
525 if (alloc)
526 free(ptr, M_XDATA);
527 m_freem(m);
528 return EINVAL;
529 }
530
531 /* Copyback and free, if we allocated. */
532 if (alloc) {
533 m_copyback(m, sizeof(struct ip6_hdr),
534 skip - sizeof(struct ip6_hdr), ptr);
535 free(ptr, M_XDATA);
536 }
537
538 break;
539 #endif /* INET6 */
540 }
541
542 return 0;
543 }
544
545 /*
546 * ah_input() gets called to verify that an input packet
547 * passes authentication.
548 */
549 static int
ah_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)550 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
551 {
552 struct auth_hash *ahx;
553 struct tdb_ident *tdbi;
554 struct tdb_crypto *tc;
555 struct m_tag *mtag;
556 struct newah *ah;
557 int hl, rplen, authsize;
558
559 struct cryptodesc *crda;
560 struct cryptop *crp;
561
562 IPSEC_ASSERT(sav != NULL, ("null SA"));
563 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
564 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
565 ("null authentication xform"));
566
567 /* Figure out header size. */
568 rplen = HDRSIZE(sav);
569
570 /* XXX don't pullup, just copy header */
571 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
572 if (ah == NULL) {
573 DPRINTF(("ah_input: cannot pullup header\n"));
574 AHSTAT_INC(ahs_hdrops); /*XXX*/
575 m_freem(m);
576 return ENOBUFS;
577 }
578
579 /* Check replay window, if applicable. */
580 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
581 AHSTAT_INC(ahs_replay);
582 DPRINTF(("%s: packet replay failure: %s\n", __func__,
583 ipsec_logsastr(sav)));
584 m_freem(m);
585 return ENOBUFS;
586 }
587
588 /* Verify AH header length. */
589 hl = ah->ah_len * sizeof (u_int32_t);
590 ahx = sav->tdb_authalgxform;
591 authsize = AUTHSIZE(sav);
592 if (hl != authsize + rplen - sizeof (struct ah)) {
593 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
594 " for packet in SA %s/%08lx\n", __func__,
595 hl, (u_long) (authsize + rplen - sizeof (struct ah)),
596 ipsec_address(&sav->sah->saidx.dst),
597 (u_long) ntohl(sav->spi)));
598 AHSTAT_INC(ahs_badauthl);
599 m_freem(m);
600 return EACCES;
601 }
602 if (skip + authsize + rplen > m->m_pkthdr.len) {
603 DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
604 " for packet in SA %s/%08lx\n", __func__,
605 m->m_pkthdr.len, (u_long) (skip + authsize + rplen),
606 ipsec_address(&sav->sah->saidx.dst),
607 (u_long) ntohl(sav->spi)));
608 AHSTAT_INC(ahs_badauthl);
609 m_freem(m);
610 return EACCES;
611 }
612 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
613
614 /* Get crypto descriptors. */
615 crp = crypto_getreq(1);
616 if (crp == NULL) {
617 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
618 AHSTAT_INC(ahs_crypto);
619 m_freem(m);
620 return ENOBUFS;
621 }
622
623 crda = crp->crp_desc;
624 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
625
626 crda->crd_skip = 0;
627 crda->crd_len = m->m_pkthdr.len;
628 crda->crd_inject = skip + rplen;
629
630 /* Authentication operation. */
631 crda->crd_alg = ahx->type;
632 crda->crd_klen = _KEYBITS(sav->key_auth);
633 crda->crd_key = sav->key_auth->key_data;
634
635 /* Find out if we've already done crypto. */
636 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
637 mtag != NULL;
638 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
639 tdbi = (struct tdb_ident *) (mtag + 1);
640 if (tdbi->proto == sav->sah->saidx.proto &&
641 tdbi->spi == sav->spi &&
642 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
643 sizeof (union sockaddr_union)))
644 break;
645 }
646
647 /* Allocate IPsec-specific opaque crypto info. */
648 if (mtag == NULL) {
649 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
650 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
651 } else {
652 /* Hash verification has already been done successfully. */
653 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
654 M_XDATA, M_NOWAIT|M_ZERO);
655 }
656 if (tc == NULL) {
657 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
658 AHSTAT_INC(ahs_crypto);
659 crypto_freereq(crp);
660 m_freem(m);
661 return ENOBUFS;
662 }
663
664 /* Only save information if crypto processing is needed. */
665 if (mtag == NULL) {
666 int error;
667
668 /*
669 * Save the authenticator, the skipped portion of the packet,
670 * and the AH header.
671 */
672 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
673
674 /* Zeroize the authenticator on the packet. */
675 m_copyback(m, skip + rplen, authsize, ipseczeroes);
676
677 /* Save ah_nxt, since ah pointer can become invalid after "massage" */
678 hl = ah->ah_nxt;
679
680 /* "Massage" the packet headers for crypto processing. */
681 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
682 skip, ahx->type, 0);
683 if (error != 0) {
684 /* NB: mbuf is free'd by ah_massage_headers */
685 AHSTAT_INC(ahs_hdrops);
686 free(tc, M_XDATA);
687 crypto_freereq(crp);
688 return error;
689 }
690 }
691
692 /* Crypto operation descriptor. */
693 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
694 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
695 crp->crp_buf = (caddr_t) m;
696 crp->crp_callback = ah_input_cb;
697 crp->crp_sid = sav->tdb_cryptoid;
698 crp->crp_opaque = (caddr_t) tc;
699
700 /* These are passed as-is to the callback. */
701 tc->tc_spi = sav->spi;
702 tc->tc_dst = sav->sah->saidx.dst;
703 tc->tc_proto = sav->sah->saidx.proto;
704 tc->tc_nxt = hl;
705 tc->tc_protoff = protoff;
706 tc->tc_skip = skip;
707 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
708 KEY_ADDREFSA(sav);
709 tc->tc_sav = sav;
710
711 if (mtag == NULL)
712 return crypto_dispatch(crp);
713 else
714 return ah_input_cb(crp);
715 }
716
717 /*
718 * AH input callback from the crypto driver.
719 */
720 static int
ah_input_cb(struct cryptop * crp)721 ah_input_cb(struct cryptop *crp)
722 {
723 int rplen, error, skip, protoff;
724 unsigned char calc[AH_ALEN_MAX];
725 struct mbuf *m;
726 struct cryptodesc *crd;
727 struct auth_hash *ahx;
728 struct tdb_crypto *tc;
729 struct m_tag *mtag;
730 struct secasvar *sav;
731 struct secasindex *saidx;
732 u_int8_t nxt;
733 caddr_t ptr;
734 int authsize;
735
736 crd = crp->crp_desc;
737
738 tc = (struct tdb_crypto *) crp->crp_opaque;
739 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
740 skip = tc->tc_skip;
741 nxt = tc->tc_nxt;
742 protoff = tc->tc_protoff;
743 mtag = (struct m_tag *) tc->tc_ptr;
744 m = (struct mbuf *) crp->crp_buf;
745
746 sav = tc->tc_sav;
747 IPSEC_ASSERT(sav != NULL, ("null SA!"));
748
749 saidx = &sav->sah->saidx;
750 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
751 saidx->dst.sa.sa_family == AF_INET6,
752 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
753
754 ahx = (struct auth_hash *) sav->tdb_authalgxform;
755
756 /* Check for crypto errors. */
757 if (crp->crp_etype) {
758 if (sav->tdb_cryptoid != 0)
759 sav->tdb_cryptoid = crp->crp_sid;
760
761 if (crp->crp_etype == EAGAIN)
762 return (crypto_dispatch(crp));
763
764 AHSTAT_INC(ahs_noxform);
765 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
766 error = crp->crp_etype;
767 goto bad;
768 } else {
769 AHSTAT_INC(ahs_hist[sav->alg_auth]);
770 crypto_freereq(crp); /* No longer needed. */
771 crp = NULL;
772 }
773
774 /* Shouldn't happen... */
775 if (m == NULL) {
776 AHSTAT_INC(ahs_crypto);
777 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
778 error = EINVAL;
779 goto bad;
780 }
781
782 /* Figure out header size. */
783 rplen = HDRSIZE(sav);
784 authsize = AUTHSIZE(sav);
785
786 /* Copy authenticator off the packet. */
787 m_copydata(m, skip + rplen, authsize, calc);
788
789 /*
790 * If we have an mtag, we don't need to verify the authenticator --
791 * it has been verified by an IPsec-aware NIC.
792 */
793 if (mtag == NULL) {
794 ptr = (caddr_t) (tc + 1);
795
796 /* Verify authenticator. */
797 if (bcmp(ptr + skip + rplen, calc, authsize)) {
798 DPRINTF(("%s: authentication hash mismatch for packet "
799 "in SA %s/%08lx\n", __func__,
800 ipsec_address(&saidx->dst),
801 (u_long) ntohl(sav->spi)));
802 AHSTAT_INC(ahs_badauth);
803 error = EACCES;
804 goto bad;
805 }
806
807 /* Fix the Next Protocol field. */
808 ((u_int8_t *) ptr)[protoff] = nxt;
809
810 /* Copyback the saved (uncooked) network headers. */
811 m_copyback(m, 0, skip, ptr);
812 } else {
813 /* Fix the Next Protocol field. */
814 m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
815 }
816
817 free(tc, M_XDATA), tc = NULL; /* No longer needed */
818
819 /*
820 * Header is now authenticated.
821 */
822 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
823
824 /*
825 * Update replay sequence number, if appropriate.
826 */
827 if (sav->replay) {
828 u_int32_t seq;
829
830 m_copydata(m, skip + offsetof(struct newah, ah_seq),
831 sizeof (seq), (caddr_t) &seq);
832 if (ipsec_updatereplay(ntohl(seq), sav)) {
833 AHSTAT_INC(ahs_replay);
834 error = ENOBUFS; /*XXX as above*/
835 goto bad;
836 }
837 }
838
839 /*
840 * Remove the AH header and authenticator from the mbuf.
841 */
842 error = m_striphdr(m, skip, rplen + authsize);
843 if (error) {
844 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
845 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
846
847 AHSTAT_INC(ahs_hdrops);
848 goto bad;
849 }
850
851 switch (saidx->dst.sa.sa_family) {
852 #ifdef INET6
853 case AF_INET6:
854 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag);
855 break;
856 #endif
857 #ifdef INET
858 case AF_INET:
859 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag);
860 break;
861 #endif
862 default:
863 panic("%s: Unexpected address family: %d saidx=%p", __func__,
864 saidx->dst.sa.sa_family, saidx);
865 }
866
867 KEY_FREESAV(&sav);
868 return error;
869 bad:
870 if (sav)
871 KEY_FREESAV(&sav);
872 if (m != NULL)
873 m_freem(m);
874 if (tc != NULL)
875 free(tc, M_XDATA);
876 if (crp != NULL)
877 crypto_freereq(crp);
878 return error;
879 }
880
881 /*
882 * AH output routine, called by ipsec[46]_process_packet().
883 */
884 static int
ah_output(struct mbuf * m,struct ipsecrequest * isr,struct mbuf ** mp,int skip,int protoff)885 ah_output(
886 struct mbuf *m,
887 struct ipsecrequest *isr,
888 struct mbuf **mp,
889 int skip,
890 int protoff)
891 {
892 struct secasvar *sav;
893 struct auth_hash *ahx;
894 struct cryptodesc *crda;
895 struct tdb_crypto *tc;
896 struct mbuf *mi;
897 struct cryptop *crp;
898 u_int16_t iplen;
899 int error, rplen, authsize, maxpacketsize, roff;
900 u_int8_t prot;
901 struct newah *ah;
902
903 sav = isr->sav;
904 IPSEC_ASSERT(sav != NULL, ("null SA"));
905 ahx = sav->tdb_authalgxform;
906 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
907
908 AHSTAT_INC(ahs_output);
909
910 /* Figure out header size. */
911 rplen = HDRSIZE(sav);
912
913 /* Check for maximum packet size violations. */
914 switch (sav->sah->saidx.dst.sa.sa_family) {
915 #ifdef INET
916 case AF_INET:
917 maxpacketsize = IP_MAXPACKET;
918 break;
919 #endif /* INET */
920 #ifdef INET6
921 case AF_INET6:
922 maxpacketsize = IPV6_MAXPACKET;
923 break;
924 #endif /* INET6 */
925 default:
926 DPRINTF(("%s: unknown/unsupported protocol family %u, "
927 "SA %s/%08lx\n", __func__,
928 sav->sah->saidx.dst.sa.sa_family,
929 ipsec_address(&sav->sah->saidx.dst),
930 (u_long) ntohl(sav->spi)));
931 AHSTAT_INC(ahs_nopf);
932 error = EPFNOSUPPORT;
933 goto bad;
934 }
935 authsize = AUTHSIZE(sav);
936 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
937 DPRINTF(("%s: packet in SA %s/%08lx got too big "
938 "(len %u, max len %u)\n", __func__,
939 ipsec_address(&sav->sah->saidx.dst),
940 (u_long) ntohl(sav->spi),
941 rplen + authsize + m->m_pkthdr.len, maxpacketsize));
942 AHSTAT_INC(ahs_toobig);
943 error = EMSGSIZE;
944 goto bad;
945 }
946
947 /* Update the counters. */
948 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
949
950 m = m_unshare(m, M_NOWAIT);
951 if (m == NULL) {
952 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
953 ipsec_address(&sav->sah->saidx.dst),
954 (u_long) ntohl(sav->spi)));
955 AHSTAT_INC(ahs_hdrops);
956 error = ENOBUFS;
957 goto bad;
958 }
959
960 /* Inject AH header. */
961 mi = m_makespace(m, skip, rplen + authsize, &roff);
962 if (mi == NULL) {
963 DPRINTF(("%s: failed to inject %u byte AH header for SA "
964 "%s/%08lx\n", __func__,
965 rplen + authsize,
966 ipsec_address(&sav->sah->saidx.dst),
967 (u_long) ntohl(sav->spi)));
968 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
969 error = ENOBUFS;
970 goto bad;
971 }
972
973 /*
974 * The AH header is guaranteed by m_makespace() to be in
975 * contiguous memory, at roff bytes offset into the returned mbuf.
976 */
977 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
978
979 /* Initialize the AH header. */
980 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
981 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
982 ah->ah_reserve = 0;
983 ah->ah_spi = sav->spi;
984
985 /* Zeroize authenticator. */
986 m_copyback(m, skip + rplen, authsize, ipseczeroes);
987
988 /* Insert packet replay counter, as requested. */
989 if (sav->replay) {
990 if (sav->replay->count == ~0 &&
991 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
992 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
993 __func__,
994 ipsec_address(&sav->sah->saidx.dst),
995 (u_long) ntohl(sav->spi)));
996 AHSTAT_INC(ahs_wrap);
997 error = EINVAL;
998 goto bad;
999 }
1000 #ifdef REGRESSION
1001 /* Emulate replay attack when ipsec_replay is TRUE. */
1002 if (!V_ipsec_replay)
1003 #endif
1004 sav->replay->count++;
1005 ah->ah_seq = htonl(sav->replay->count);
1006 }
1007
1008 /* Get crypto descriptors. */
1009 crp = crypto_getreq(1);
1010 if (crp == NULL) {
1011 DPRINTF(("%s: failed to acquire crypto descriptors\n",
1012 __func__));
1013 AHSTAT_INC(ahs_crypto);
1014 error = ENOBUFS;
1015 goto bad;
1016 }
1017
1018 crda = crp->crp_desc;
1019
1020 crda->crd_skip = 0;
1021 crda->crd_inject = skip + rplen;
1022 crda->crd_len = m->m_pkthdr.len;
1023
1024 /* Authentication operation. */
1025 crda->crd_alg = ahx->type;
1026 crda->crd_key = sav->key_auth->key_data;
1027 crda->crd_klen = _KEYBITS(sav->key_auth);
1028
1029 /* Allocate IPsec-specific opaque crypto info. */
1030 tc = (struct tdb_crypto *) malloc(
1031 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1032 if (tc == NULL) {
1033 crypto_freereq(crp);
1034 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
1035 AHSTAT_INC(ahs_crypto);
1036 error = ENOBUFS;
1037 goto bad;
1038 }
1039
1040 /* Save the skipped portion of the packet. */
1041 m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1042
1043 /*
1044 * Fix IP header length on the header used for
1045 * authentication. We don't need to fix the original
1046 * header length as it will be fixed by our caller.
1047 */
1048 switch (sav->sah->saidx.dst.sa.sa_family) {
1049 #ifdef INET
1050 case AF_INET:
1051 bcopy(((caddr_t)(tc + 1)) +
1052 offsetof(struct ip, ip_len),
1053 (caddr_t) &iplen, sizeof(u_int16_t));
1054 iplen = htons(ntohs(iplen) + rplen + authsize);
1055 m_copyback(m, offsetof(struct ip, ip_len),
1056 sizeof(u_int16_t), (caddr_t) &iplen);
1057 break;
1058 #endif /* INET */
1059
1060 #ifdef INET6
1061 case AF_INET6:
1062 bcopy(((caddr_t)(tc + 1)) +
1063 offsetof(struct ip6_hdr, ip6_plen),
1064 (caddr_t) &iplen, sizeof(u_int16_t));
1065 iplen = htons(ntohs(iplen) + rplen + authsize);
1066 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1067 sizeof(u_int16_t), (caddr_t) &iplen);
1068 break;
1069 #endif /* INET6 */
1070 }
1071
1072 /* Fix the Next Header field in saved header. */
1073 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1074
1075 /* Update the Next Protocol field in the IP header. */
1076 prot = IPPROTO_AH;
1077 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1078
1079 /* "Massage" the packet headers for crypto processing. */
1080 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1081 skip, ahx->type, 1);
1082 if (error != 0) {
1083 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1084 free(tc, M_XDATA);
1085 crypto_freereq(crp);
1086 goto bad;
1087 }
1088
1089 /* Crypto operation descriptor. */
1090 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1091 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1092 crp->crp_buf = (caddr_t) m;
1093 crp->crp_callback = ah_output_cb;
1094 crp->crp_sid = sav->tdb_cryptoid;
1095 crp->crp_opaque = (caddr_t) tc;
1096
1097 /* These are passed as-is to the callback. */
1098 tc->tc_isr = isr;
1099 KEY_ADDREFSA(sav);
1100 tc->tc_sav = sav;
1101 tc->tc_spi = sav->spi;
1102 tc->tc_dst = sav->sah->saidx.dst;
1103 tc->tc_proto = sav->sah->saidx.proto;
1104 tc->tc_skip = skip;
1105 tc->tc_protoff = protoff;
1106
1107 return crypto_dispatch(crp);
1108 bad:
1109 if (m)
1110 m_freem(m);
1111 return (error);
1112 }
1113
1114 /*
1115 * AH output callback from the crypto driver.
1116 */
1117 static int
ah_output_cb(struct cryptop * crp)1118 ah_output_cb(struct cryptop *crp)
1119 {
1120 int skip, protoff, error;
1121 struct tdb_crypto *tc;
1122 struct ipsecrequest *isr;
1123 struct secasvar *sav;
1124 struct mbuf *m;
1125 caddr_t ptr;
1126
1127 tc = (struct tdb_crypto *) crp->crp_opaque;
1128 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
1129 skip = tc->tc_skip;
1130 protoff = tc->tc_protoff;
1131 ptr = (caddr_t) (tc + 1);
1132 m = (struct mbuf *) crp->crp_buf;
1133
1134 isr = tc->tc_isr;
1135 IPSECREQUEST_LOCK(isr);
1136 sav = tc->tc_sav;
1137 /* With the isr lock released SA pointer can be updated. */
1138 if (sav != isr->sav) {
1139 AHSTAT_INC(ahs_notdb);
1140 DPRINTF(("%s: SA expired while in crypto\n", __func__));
1141 error = ENOBUFS; /*XXX*/
1142 goto bad;
1143 }
1144
1145 /* Check for crypto errors. */
1146 if (crp->crp_etype) {
1147 if (sav->tdb_cryptoid != 0)
1148 sav->tdb_cryptoid = crp->crp_sid;
1149
1150 if (crp->crp_etype == EAGAIN) {
1151 IPSECREQUEST_UNLOCK(isr);
1152 return (crypto_dispatch(crp));
1153 }
1154
1155 AHSTAT_INC(ahs_noxform);
1156 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1157 error = crp->crp_etype;
1158 goto bad;
1159 }
1160
1161 /* Shouldn't happen... */
1162 if (m == NULL) {
1163 AHSTAT_INC(ahs_crypto);
1164 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1165 error = EINVAL;
1166 goto bad;
1167 }
1168 AHSTAT_INC(ahs_hist[sav->alg_auth]);
1169
1170 /*
1171 * Copy original headers (with the new protocol number) back
1172 * in place.
1173 */
1174 m_copyback(m, 0, skip, ptr);
1175
1176 /* No longer needed. */
1177 free(tc, M_XDATA);
1178 crypto_freereq(crp);
1179
1180 #ifdef REGRESSION
1181 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1182 if (V_ipsec_integrity) {
1183 int alen;
1184
1185 /*
1186 * Corrupt HMAC if we want to test integrity verification of
1187 * the other side.
1188 */
1189 alen = AUTHSIZE(sav);
1190 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1191 }
1192 #endif
1193
1194 /* NB: m is reclaimed by ipsec_process_done. */
1195 error = ipsec_process_done(m, isr);
1196 KEY_FREESAV(&sav);
1197 IPSECREQUEST_UNLOCK(isr);
1198 return error;
1199 bad:
1200 if (sav)
1201 KEY_FREESAV(&sav);
1202 IPSECREQUEST_UNLOCK(isr);
1203 if (m)
1204 m_freem(m);
1205 free(tc, M_XDATA);
1206 crypto_freereq(crp);
1207 return error;
1208 }
1209
1210 static struct xformsw ah_xformsw = {
1211 XF_AH, XFT_AUTH, "IPsec AH",
1212 ah_init, ah_zeroize, ah_input, ah_output,
1213 };
1214
1215 static void
ah_attach(void)1216 ah_attach(void)
1217 {
1218
1219 xform_register(&ah_xformsw);
1220 }
1221
1222 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
1223