1 /* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */
2 /*-
3 * The authors of this code are John Ioannidis (ji@tla.org),
4 * Angelos D. Keromytis (kermit@csd.uch.gr) and
5 * Niels Provos (provos@physnet.uni-hamburg.de).
6 *
7 * The original version of this code was written by John Ioannidis
8 * for BSD/OS in Athens, Greece, in November 1995.
9 *
10 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
11 * by Angelos D. Keromytis.
12 *
13 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
14 * and Niels Provos.
15 *
16 * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist.
17 *
18 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
19 * Angelos D. Keromytis and Niels Provos.
20 * Copyright (c) 1999 Niklas Hallqvist.
21 * Copyright (c) 2001 Angelos D. Keromytis.
22 *
23 * Permission to use, copy, and modify this software with or without fee
24 * is hereby granted, provided that this entire notice is included in
25 * all copies of any software which is or includes a copy or
26 * modification of this software.
27 * You may use this code under the GNU public license if you so wish. Please
28 * contribute changes back to the authors under this freer than GPL license
29 * so that we may further the use of strong encryption without limitations to
30 * all.
31 *
32 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
33 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
34 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
35 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
36 * PURPOSE.
37 */
38 #include "opt_inet.h"
39 #include "opt_inet6.h"
40 #include "opt_ipsec.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/socket.h>
47 #include <sys/syslog.h>
48 #include <sys/kernel.h>
49 #include <sys/lock.h>
50 #include <sys/mutex.h>
51 #include <sys/sysctl.h>
52
53 #include <net/if.h>
54 #include <net/vnet.h>
55
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/ip.h>
59 #include <netinet/ip_ecn.h>
60 #include <netinet/ip6.h>
61
62 #include <netipsec/ipsec.h>
63 #include <netipsec/ah.h>
64 #include <netipsec/ah_var.h>
65 #include <netipsec/xform.h>
66
67 #ifdef INET6
68 #include <netinet6/ip6_var.h>
69 #include <netipsec/ipsec6.h>
70 #include <netinet6/ip6_ecn.h>
71 #endif
72
73 #include <netipsec/key.h>
74 #include <netipsec/key_debug.h>
75
76 #include <opencrypto/cryptodev.h>
77
78 /*
79 * Return header size in bytes. The old protocol did not support
80 * the replay counter; the new protocol always includes the counter.
81 */
82 #define HDRSIZE(sav) \
83 (((sav)->flags & SADB_X_EXT_OLD) ? \
84 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
85 /*
86 * Return authenticator size in bytes, based on a field in the
87 * algorithm descriptor.
88 */
89 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \
90 xform_ah_authsize((sav)->tdb_authalgxform))
91
92 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
93 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
94 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat);
95 VNET_PCPUSTAT_SYSINIT(ahstat);
96
97 #ifdef VIMAGE
98 VNET_PCPUSTAT_SYSUNINIT(ahstat);
99 #endif /* VIMAGE */
100
101 #ifdef INET
102 SYSCTL_DECL(_net_inet_ah);
103 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable,
104 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
105 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos,
106 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
107 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat,
108 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)");
109 #endif
110
111 static MALLOC_DEFINE(M_AH, "ah", "IPsec AH");
112
113 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
114
115 static int ah_input_cb(struct cryptop*);
116 static int ah_output_cb(struct cryptop*);
117
118 int
xform_ah_authsize(const struct auth_hash * esph)119 xform_ah_authsize(const struct auth_hash *esph)
120 {
121 int alen;
122
123 if (esph == NULL)
124 return 0;
125
126 switch (esph->type) {
127 case CRYPTO_SHA2_256_HMAC:
128 case CRYPTO_SHA2_384_HMAC:
129 case CRYPTO_SHA2_512_HMAC:
130 alen = esph->hashsize / 2; /* RFC4868 2.3 */
131 break;
132
133 case CRYPTO_POLY1305:
134 case CRYPTO_AES_NIST_GMAC:
135 alen = esph->hashsize;
136 break;
137
138 default:
139 alen = AH_HMAC_HASHLEN;
140 break;
141 }
142
143 return alen;
144 }
145
146 size_t
ah_hdrsiz(struct secasvar * sav)147 ah_hdrsiz(struct secasvar *sav)
148 {
149 size_t size;
150
151 if (sav != NULL) {
152 int authsize, rplen, align;
153
154 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
155 /*XXX not right for null algorithm--does it matter??*/
156
157 /* RFC4302: use the correct alignment. */
158 align = sizeof(uint32_t);
159 #ifdef INET6
160 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) {
161 align = sizeof(uint64_t);
162 }
163 #endif
164 rplen = HDRSIZE(sav);
165 authsize = AUTHSIZE(sav);
166 size = roundup(rplen + authsize, align);
167 } else {
168 /* default guess */
169 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
170 }
171 return size;
172 }
173
174 /*
175 * NB: public for use by esp_init.
176 */
177 int
ah_init0(struct secasvar * sav,struct xformsw * xsp,struct crypto_session_params * csp)178 ah_init0(struct secasvar *sav, struct xformsw *xsp,
179 struct crypto_session_params *csp)
180 {
181 const struct auth_hash *thash;
182 int keylen;
183
184 thash = auth_algorithm_lookup(sav->alg_auth);
185 if (thash == NULL) {
186 DPRINTF(("%s: unsupported authentication algorithm %u\n",
187 __func__, sav->alg_auth));
188 return EINVAL;
189 }
190
191 /*
192 * Verify the replay state block allocation is consistent with
193 * the protocol type. We check here so we can make assumptions
194 * later during protocol processing.
195 */
196 /* NB: replay state is setup elsewhere (sigh) */
197 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
198 DPRINTF(("%s: replay state block inconsistency, "
199 "%s algorithm %s replay state\n", __func__,
200 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
201 sav->replay == NULL ? "without" : "with"));
202 return EINVAL;
203 }
204 if (sav->key_auth == NULL) {
205 DPRINTF(("%s: no authentication key for %s algorithm\n",
206 __func__, thash->name));
207 return EINVAL;
208 }
209 keylen = _KEYLEN(sav->key_auth);
210 if (keylen > thash->keysize && thash->keysize != 0) {
211 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
212 "keysize less than %d\n", __func__,
213 keylen, thash->name, thash->keysize));
214 return EINVAL;
215 }
216
217 sav->tdb_xform = xsp;
218 sav->tdb_authalgxform = thash;
219
220 /* Initialize crypto session. */
221 csp->csp_auth_alg = sav->tdb_authalgxform->type;
222 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) {
223 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8;
224 csp->csp_auth_key = sav->key_auth->key_data;
225 };
226 csp->csp_auth_mlen = AUTHSIZE(sav);
227
228 return 0;
229 }
230
231 /*
232 * ah_init() is called when an SPI is being set up.
233 */
234 static int
ah_init(struct secasvar * sav,struct xformsw * xsp)235 ah_init(struct secasvar *sav, struct xformsw *xsp)
236 {
237 struct crypto_session_params csp;
238 int error;
239
240 memset(&csp, 0, sizeof(csp));
241 csp.csp_mode = CSP_MODE_DIGEST;
242
243 if (sav->flags & SADB_X_SAFLAGS_ESN)
244 csp.csp_flags |= CSP_F_ESN;
245
246 error = ah_init0(sav, xsp, &csp);
247 return error ? error :
248 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
249 }
250
251 static void
ah_cleanup(struct secasvar * sav)252 ah_cleanup(struct secasvar *sav)
253 {
254
255 crypto_freesession(sav->tdb_cryptoid);
256 sav->tdb_cryptoid = NULL;
257 sav->tdb_authalgxform = NULL;
258 }
259
260 /*
261 * Massage IPv4/IPv6 headers for AH processing.
262 */
263 static int
ah_massage_headers(struct mbuf ** m0,int proto,int skip,int alg,int out)264 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
265 {
266 struct mbuf *m = *m0;
267 unsigned char *ptr;
268 int off, count;
269
270 #ifdef INET
271 struct ip *ip;
272 #endif /* INET */
273
274 #ifdef INET6
275 struct ip6_ext *ip6e;
276 struct ip6_hdr ip6;
277 int ad, alloc, nxt, noff;
278 #endif /* INET6 */
279
280 switch (proto) {
281 #ifdef INET
282 case AF_INET:
283 /*
284 * This is the least painful way of dealing with IPv4 header
285 * and option processing -- just make sure they're in
286 * contiguous memory.
287 */
288 *m0 = m = m_pullup(m, skip);
289 if (m == NULL) {
290 DPRINTF(("%s: m_pullup failed\n", __func__));
291 return ENOBUFS;
292 }
293
294 /* Fix the IP header */
295 ip = mtod(m, struct ip *);
296 if (V_ah_cleartos)
297 ip->ip_tos = 0;
298 ip->ip_ttl = 0;
299 ip->ip_sum = 0;
300 ip->ip_off = htons(0);
301
302 ptr = mtod(m, unsigned char *);
303
304 /* IPv4 option processing */
305 for (off = sizeof(struct ip); off < skip;) {
306 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
307 off + 1 < skip)
308 ;
309 else {
310 DPRINTF(("%s: illegal IPv4 option length for "
311 "option %d\n", __func__, ptr[off]));
312
313 m_freem(m);
314 return EINVAL;
315 }
316
317 switch (ptr[off]) {
318 case IPOPT_EOL:
319 off = skip; /* End the loop. */
320 break;
321
322 case IPOPT_NOP:
323 off++;
324 break;
325
326 case IPOPT_SECURITY: /* 0x82 */
327 case 0x85: /* Extended security. */
328 case 0x86: /* Commercial security. */
329 case 0x94: /* Router alert */
330 case 0x95: /* RFC1770 */
331 /* Sanity check for option length. */
332 if (ptr[off + 1] < 2) {
333 DPRINTF(("%s: illegal IPv4 option "
334 "length for option %d\n",
335 __func__, ptr[off]));
336
337 m_freem(m);
338 return EINVAL;
339 }
340
341 off += ptr[off + 1];
342 break;
343
344 case IPOPT_LSRR:
345 case IPOPT_SSRR:
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 /*
357 * On output, if we have either of the
358 * source routing options, we should
359 * swap the destination address of the
360 * IP header with the last address
361 * specified in the option, as that is
362 * what the destination's IP header
363 * will look like.
364 */
365 if (out)
366 bcopy(ptr + off + ptr[off + 1] -
367 sizeof(struct in_addr),
368 &(ip->ip_dst), sizeof(struct in_addr));
369
370 /* Fall through */
371 default:
372 /* Sanity check for option length. */
373 if (ptr[off + 1] < 2) {
374 DPRINTF(("%s: illegal IPv4 option "
375 "length for option %d\n",
376 __func__, ptr[off]));
377 m_freem(m);
378 return EINVAL;
379 }
380
381 /* Zeroize all other options. */
382 count = ptr[off + 1];
383 bcopy(ipseczeroes, ptr + off, count);
384 off += count;
385 break;
386 }
387
388 /* Sanity check. */
389 if (off > skip) {
390 DPRINTF(("%s: malformed IPv4 options header\n",
391 __func__));
392
393 m_freem(m);
394 return EINVAL;
395 }
396 }
397
398 break;
399 #endif /* INET */
400
401 #ifdef INET6
402 case AF_INET6: /* Ugly... */
403 /* Copy and "cook" the IPv6 header. */
404 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
405
406 /* We don't do IPv6 Jumbograms. */
407 if (ip6.ip6_plen == 0) {
408 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
409 m_freem(m);
410 return EMSGSIZE;
411 }
412
413 ip6.ip6_flow = 0;
414 ip6.ip6_hlim = 0;
415 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
416 ip6.ip6_vfc |= IPV6_VERSION;
417
418 /* Scoped address handling. */
419 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
420 ip6.ip6_src.s6_addr16[1] = 0;
421 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
422 ip6.ip6_dst.s6_addr16[1] = 0;
423
424 /* Done with IPv6 header. */
425 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
426
427 /* Let's deal with the remaining headers (if any). */
428 if (skip - sizeof(struct ip6_hdr) > 0) {
429 if (m->m_len <= skip) {
430 ptr = (unsigned char *) malloc(
431 skip - sizeof(struct ip6_hdr),
432 M_AH, M_NOWAIT);
433 if (ptr == NULL) {
434 DPRINTF(("%s: failed to allocate memory"
435 "for IPv6 headers\n",__func__));
436 m_freem(m);
437 return ENOBUFS;
438 }
439
440 /*
441 * Copy all the protocol headers after
442 * the IPv6 header.
443 */
444 m_copydata(m, sizeof(struct ip6_hdr),
445 skip - sizeof(struct ip6_hdr), ptr);
446 alloc = 1;
447 } else {
448 /* No need to allocate memory. */
449 ptr = mtod(m, unsigned char *) +
450 sizeof(struct ip6_hdr);
451 alloc = 0;
452 }
453 } else
454 break;
455
456 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
457
458 for (off = 0; off < skip - sizeof(struct ip6_hdr);)
459 switch (nxt) {
460 case IPPROTO_HOPOPTS:
461 case IPPROTO_DSTOPTS:
462 ip6e = (struct ip6_ext *)(ptr + off);
463 noff = off + ((ip6e->ip6e_len + 1) << 3);
464
465 /* Sanity check. */
466 if (noff > skip - sizeof(struct ip6_hdr))
467 goto error6;
468
469 /*
470 * Zero out mutable options.
471 */
472 for (count = off + sizeof(struct ip6_ext);
473 count < noff;) {
474 if (ptr[count] == IP6OPT_PAD1) {
475 count++;
476 continue; /* Skip padding. */
477 }
478
479 ad = ptr[count + 1] + 2;
480 if (count + ad > noff)
481 goto error6;
482
483 if (ptr[count] & IP6OPT_MUTABLE)
484 memset(ptr + count, 0, ad);
485 count += ad;
486 }
487
488 if (count != noff)
489 goto error6;
490
491 /* Advance. */
492 off += ((ip6e->ip6e_len + 1) << 3);
493 nxt = ip6e->ip6e_nxt;
494 break;
495
496 case IPPROTO_ROUTING:
497 /*
498 * Always include routing headers in
499 * computation.
500 */
501 ip6e = (struct ip6_ext *) (ptr + off);
502 off += ((ip6e->ip6e_len + 1) << 3);
503 nxt = ip6e->ip6e_nxt;
504 break;
505
506 default:
507 DPRINTF(("%s: unexpected IPv6 header type %d",
508 __func__, off));
509 error6:
510 if (alloc)
511 free(ptr, M_AH);
512 m_freem(m);
513 return EINVAL;
514 }
515
516 /* Copyback and free, if we allocated. */
517 if (alloc) {
518 m_copyback(m, sizeof(struct ip6_hdr),
519 skip - sizeof(struct ip6_hdr), ptr);
520 free(ptr, M_AH);
521 }
522
523 break;
524 #endif /* INET6 */
525 }
526
527 return 0;
528 }
529
530 /*
531 * ah_input() gets called to verify that an input packet
532 * passes authentication.
533 */
534 static int
ah_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)535 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
536 {
537 IPSEC_DEBUG_DECLARE(char buf[128]);
538 const struct auth_hash *ahx;
539 struct cryptop *crp;
540 struct xform_data *xd;
541 struct newah *ah;
542 crypto_session_t cryptoid;
543 int hl, rplen, authsize, ahsize, error;
544 uint32_t seqh;
545
546 SECASVAR_RLOCK_TRACKER;
547
548 IPSEC_ASSERT(sav != NULL, ("null SA"));
549 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
550 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
551 ("null authentication xform"));
552
553 /* Figure out header size. */
554 rplen = HDRSIZE(sav);
555
556 if (m->m_len < skip + rplen) {
557 m = m_pullup(m, skip + rplen);
558 if (m == NULL) {
559 DPRINTF(("ah_input: cannot pullup header\n"));
560 AHSTAT_INC(ahs_hdrops); /*XXX*/
561 error = ENOBUFS;
562 goto bad;
563 }
564 }
565 ah = (struct newah *)(mtod(m, caddr_t) + skip);
566
567 /* Check replay window, if applicable. */
568 SECASVAR_RLOCK(sav);
569 if (sav->replay != NULL && sav->replay->wsize != 0 &&
570 ipsec_chkreplay(ntohl(ah->ah_seq), &seqh, sav) == 0) {
571 SECASVAR_RUNLOCK(sav);
572 AHSTAT_INC(ahs_replay);
573 DPRINTF(("%s: packet replay failure: %s\n", __func__,
574 ipsec_sa2str(sav, buf, sizeof(buf))));
575 error = EACCES;
576 goto bad;
577 }
578 cryptoid = sav->tdb_cryptoid;
579 SECASVAR_RUNLOCK(sav);
580
581 /* Verify AH header length. */
582 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t));
583 ahx = sav->tdb_authalgxform;
584 authsize = AUTHSIZE(sav);
585 ahsize = ah_hdrsiz(sav);
586 if (hl != ahsize) {
587 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
588 " for packet in SA %s/%08lx\n", __func__, hl,
589 (u_long)ahsize,
590 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
591 (u_long) ntohl(sav->spi)));
592 AHSTAT_INC(ahs_badauthl);
593 error = EACCES;
594 goto bad;
595 }
596 if (skip + ahsize > m->m_pkthdr.len) {
597 DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
598 " for packet in SA %s/%08lx\n", __func__,
599 m->m_pkthdr.len, (u_long)(skip + ahsize),
600 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
601 (u_long) ntohl(sav->spi)));
602 AHSTAT_INC(ahs_badauthl);
603 error = EACCES;
604 goto bad;
605 }
606 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
607
608 /* Get crypto descriptors. */
609 crp = crypto_getreq(cryptoid, M_NOWAIT);
610 if (crp == NULL) {
611 DPRINTF(("%s: failed to acquire crypto descriptor\n",
612 __func__));
613 AHSTAT_INC(ahs_crypto);
614 error = ENOBUFS;
615 goto bad;
616 }
617
618 crp->crp_payload_start = 0;
619 crp->crp_payload_length = m->m_pkthdr.len;
620 crp->crp_digest_start = skip + rplen;
621
622 /* Allocate IPsec-specific opaque crypto info. */
623 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_AH,
624 M_NOWAIT | M_ZERO);
625 if (xd == NULL) {
626 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
627 AHSTAT_INC(ahs_crypto);
628 crypto_freereq(crp);
629 error = ENOBUFS;
630 goto bad;
631 }
632
633 /*
634 * Save the authenticator, the skipped portion of the packet,
635 * and the AH header.
636 */
637 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1));
638
639 /* Zeroize the authenticator on the packet. */
640 m_copyback(m, skip + rplen, authsize, ipseczeroes);
641
642 /* Save ah_nxt, since ah pointer can become invalid after "massage" */
643 hl = ah->ah_nxt;
644
645 /* "Massage" the packet headers for crypto processing. */
646 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
647 skip, ahx->type, 0);
648 if (error != 0) {
649 /* NB: mbuf is free'd by ah_massage_headers */
650 AHSTAT_INC(ahs_hdrops);
651 free(xd, M_AH);
652 crypto_freereq(crp);
653 key_freesav(&sav);
654 return (error);
655 }
656
657 /* Crypto operation descriptor. */
658 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST;
659 crp->crp_flags = CRYPTO_F_CBIFSYNC;
660 crypto_use_mbuf(crp, m);
661 crp->crp_callback = ah_input_cb;
662 crp->crp_opaque = xd;
663
664 if (sav->flags & SADB_X_SAFLAGS_ESN &&
665 sav->replay != NULL && sav->replay->wsize != 0) {
666 seqh = htonl(seqh);
667 memcpy(crp->crp_esn, &seqh, sizeof(seqh));
668 }
669
670 /* These are passed as-is to the callback. */
671 xd->sav = sav;
672 xd->nxt = hl;
673 xd->protoff = protoff;
674 xd->skip = skip;
675 xd->cryptoid = cryptoid;
676 xd->vnet = curvnet;
677 if (V_async_crypto)
678 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED));
679 else
680 return (crypto_dispatch(crp));
681 bad:
682 m_freem(m);
683 key_freesav(&sav);
684 return (error);
685 }
686
687 /*
688 * AH input callback from the crypto driver.
689 */
690 static int
ah_input_cb(struct cryptop * crp)691 ah_input_cb(struct cryptop *crp)
692 {
693 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
694 unsigned char calc[AH_ALEN_MAX];
695 struct rm_priotracker sahtree_tracker;
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 SECASVAR_RLOCK_TRACKER;
706
707 m = crp->crp_buf.cb_mbuf;
708 xd = crp->crp_opaque;
709 CURVNET_SET(xd->vnet);
710 sav = xd->sav;
711 skip = xd->skip;
712 nxt = xd->nxt;
713 protoff = xd->protoff;
714 cryptoid = xd->cryptoid;
715 ipsec_sahtree_rlock(&sahtree_tracker);
716 if (sav->state >= SADB_SASTATE_DEAD) {
717 /* saidx is freed */
718 DPRINTF(("%s: dead SA %p spi %#x\n", __func__, sav, sav->spi));
719 AHSTAT_INC(ahs_notdb);
720 error = ESRCH;
721 goto bad;
722 }
723 saidx = &sav->sah->saidx;
724 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
725 saidx->dst.sa.sa_family == AF_INET6,
726 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
727
728 /* Check for crypto errors. */
729 if (crp->crp_etype) {
730 if (crp->crp_etype == EAGAIN) {
731 /* Reset the session ID */
732 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
733 crypto_freesession(cryptoid);
734 xd->cryptoid = crp->crp_session;
735 CURVNET_RESTORE();
736 return (crypto_dispatch(crp));
737 }
738 AHSTAT_INC(ahs_noxform);
739 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
740 error = crp->crp_etype;
741 goto bad;
742 } else {
743 AHSTAT_INC2(ahs_hist, sav->alg_auth);
744 crypto_freereq(crp); /* No longer needed. */
745 crp = NULL;
746 }
747
748 /* Shouldn't happen... */
749 if (m == NULL) {
750 AHSTAT_INC(ahs_crypto);
751 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
752 error = EINVAL;
753 goto bad;
754 }
755
756 /* Figure out header size. */
757 rplen = HDRSIZE(sav);
758 authsize = AUTHSIZE(sav);
759 ahsize = ah_hdrsiz(sav);
760
761 /* Copy authenticator off the packet. */
762 m_copydata(m, skip + rplen, authsize, calc);
763
764 /* Verify authenticator. */
765 ptr = (caddr_t) (xd + 1);
766 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
767 DPRINTF(("%s: authentication hash mismatch for packet "
768 "in SA %s/%08lx\n", __func__,
769 ipsec_address(&saidx->dst, buf, sizeof(buf)),
770 (u_long) ntohl(sav->spi)));
771 AHSTAT_INC(ahs_badauth);
772 error = EACCES;
773 goto bad;
774 }
775 /* Fix the Next Protocol field. */
776 ((uint8_t *) ptr)[protoff] = nxt;
777
778 /* Copyback the saved (uncooked) network headers. */
779 m_copyback(m, 0, skip, ptr);
780 free(xd, M_AH), xd = NULL; /* No longer needed */
781
782 /*
783 * Header is now authenticated.
784 */
785 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
786
787 /*
788 * Update replay sequence number, if appropriate.
789 */
790 if (sav->replay) {
791 u_int32_t seq;
792
793 m_copydata(m, skip + offsetof(struct newah, ah_seq),
794 sizeof (seq), (caddr_t) &seq);
795 SECASVAR_RLOCK(sav);
796 if (ipsec_updatereplay(ntohl(seq), sav)) {
797 SECASVAR_RUNLOCK(sav);
798 AHSTAT_INC(ahs_replay);
799 error = EACCES;
800 goto bad;
801 }
802 SECASVAR_RUNLOCK(sav);
803 }
804
805 /*
806 * Remove the AH header and authenticator from the mbuf.
807 */
808 error = m_striphdr(m, skip, ahsize);
809 if (error) {
810 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
811 ipsec_address(&saidx->dst, buf, sizeof(buf)),
812 (u_long) ntohl(sav->spi)));
813 AHSTAT_INC(ahs_hdrops);
814 goto bad;
815 }
816
817 switch (saidx->dst.sa.sa_family) {
818 #ifdef INET6
819 case AF_INET6:
820 error = ipsec6_common_input_cb(m, sav, skip, protoff,
821 &sahtree_tracker);
822 break;
823 #endif
824 #ifdef INET
825 case AF_INET:
826 error = ipsec4_common_input_cb(m, sav, skip, protoff,
827 &sahtree_tracker);
828 break;
829 #endif
830 default:
831 panic("%s: Unexpected address family: %d saidx=%p", __func__,
832 saidx->dst.sa.sa_family, saidx);
833 }
834 CURVNET_RESTORE();
835 return error;
836 bad:
837 ipsec_sahtree_runlock(&sahtree_tracker);
838 CURVNET_RESTORE();
839 if (sav)
840 key_freesav(&sav);
841 if (m != NULL)
842 m_freem(m);
843 if (xd != NULL)
844 free(xd, M_AH);
845 if (crp != NULL)
846 crypto_freereq(crp);
847 return error;
848 }
849
850 /*
851 * AH output routine, called by ipsec[46]_perform_request().
852 */
853 static int
ah_output(struct mbuf * m,struct secpolicy * sp,struct secasvar * sav,u_int idx,int skip,int protoff)854 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
855 u_int idx, int skip, int protoff)
856 {
857 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
858 const struct auth_hash *ahx;
859 struct xform_data *xd;
860 struct mbuf *mi;
861 struct cryptop *crp;
862 struct newah *ah;
863 crypto_session_t cryptoid;
864 uint16_t iplen;
865 int error, rplen, authsize, ahsize, maxpacketsize, roff;
866 uint8_t prot;
867 uint32_t seqh;
868
869 SECASVAR_RLOCK_TRACKER;
870
871 IPSEC_ASSERT(sav != NULL, ("null SA"));
872 ahx = sav->tdb_authalgxform;
873 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
874
875 AHSTAT_INC(ahs_output);
876
877 /* Figure out header size. */
878 rplen = HDRSIZE(sav);
879 authsize = AUTHSIZE(sav);
880 ahsize = ah_hdrsiz(sav);
881
882 /* Check for maximum packet size violations. */
883 switch (sav->sah->saidx.dst.sa.sa_family) {
884 #ifdef INET
885 case AF_INET:
886 maxpacketsize = IP_MAXPACKET;
887 break;
888 #endif /* INET */
889 #ifdef INET6
890 case AF_INET6:
891 maxpacketsize = IPV6_MAXPACKET;
892 break;
893 #endif /* INET6 */
894 default:
895 DPRINTF(("%s: unknown/unsupported protocol family %u, "
896 "SA %s/%08lx\n", __func__,
897 sav->sah->saidx.dst.sa.sa_family,
898 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
899 (u_long) ntohl(sav->spi)));
900 AHSTAT_INC(ahs_nopf);
901 error = EPFNOSUPPORT;
902 goto bad;
903 }
904 if (ahsize + m->m_pkthdr.len > maxpacketsize) {
905 DPRINTF(("%s: packet in SA %s/%08lx got too big "
906 "(len %u, max len %u)\n", __func__,
907 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
908 (u_long) ntohl(sav->spi),
909 ahsize + m->m_pkthdr.len, maxpacketsize));
910 AHSTAT_INC(ahs_toobig);
911 error = EMSGSIZE;
912 goto bad;
913 }
914
915 /* Update the counters. */
916 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
917
918 m = m_unshare(m, M_NOWAIT);
919 if (m == NULL) {
920 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
921 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
922 (u_long) ntohl(sav->spi)));
923 AHSTAT_INC(ahs_hdrops);
924 error = ENOBUFS;
925 goto bad;
926 }
927
928 /* Inject AH header. */
929 mi = m_makespace(m, skip, ahsize, &roff);
930 if (mi == NULL) {
931 DPRINTF(("%s: failed to inject %u byte AH header for SA "
932 "%s/%08lx\n", __func__, ahsize,
933 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
934 (u_long) ntohl(sav->spi)));
935 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
936 error = ENOBUFS;
937 goto bad;
938 }
939
940 /*
941 * The AH header is guaranteed by m_makespace() to be in
942 * contiguous memory, at roff bytes offset into the returned mbuf.
943 */
944 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
945
946 /* Initialize the AH header. */
947 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
948 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t);
949 ah->ah_reserve = 0;
950 ah->ah_spi = sav->spi;
951
952 /* Zeroize authenticator. */
953 m_copyback(m, skip + rplen, authsize, ipseczeroes);
954
955 /* Zeroize padding */
956 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize),
957 ipseczeroes);
958
959 /* Insert packet replay counter, as requested. */
960 SECASVAR_RLOCK(sav);
961 if (sav->replay) {
962 SECREPLAY_LOCK(sav->replay);
963 if ((sav->replay->count == ~0 ||
964 (!(sav->flags & SADB_X_SAFLAGS_ESN) &&
965 ((uint32_t)sav->replay->count) == ~0)) &&
966 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
967 SECREPLAY_UNLOCK(sav->replay);
968 SECASVAR_RUNLOCK(sav);
969 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
970 __func__, ipsec_address(&sav->sah->saidx.dst, buf,
971 sizeof(buf)), (u_long) ntohl(sav->spi)));
972 AHSTAT_INC(ahs_wrap);
973 error = EACCES;
974 goto bad;
975 }
976 #ifdef REGRESSION
977 /* Emulate replay attack when ipsec_replay is TRUE. */
978 if (!V_ipsec_replay)
979 #endif
980 sav->replay->count++;
981 ah->ah_seq = htonl((uint32_t)sav->replay->count);
982 SECREPLAY_UNLOCK(sav->replay);
983 }
984 cryptoid = sav->tdb_cryptoid;
985 SECASVAR_RUNLOCK(sav);
986
987 /* Get crypto descriptors. */
988 crp = crypto_getreq(cryptoid, M_NOWAIT);
989 if (crp == NULL) {
990 DPRINTF(("%s: failed to acquire crypto descriptors\n",
991 __func__));
992 AHSTAT_INC(ahs_crypto);
993 error = ENOBUFS;
994 goto bad;
995 }
996
997 crp->crp_payload_start = 0;
998 crp->crp_payload_length = m->m_pkthdr.len;
999 crp->crp_digest_start = skip + rplen;
1000
1001 /* Allocate IPsec-specific opaque crypto info. */
1002 xd = malloc(sizeof(struct xform_data) + skip, M_AH,
1003 M_NOWAIT | M_ZERO);
1004 if (xd == NULL) {
1005 crypto_freereq(crp);
1006 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
1007 AHSTAT_INC(ahs_crypto);
1008 error = ENOBUFS;
1009 goto bad;
1010 }
1011
1012 /* Save the skipped portion of the packet. */
1013 m_copydata(m, 0, skip, (caddr_t) (xd + 1));
1014
1015 /*
1016 * Fix IP header length on the header used for
1017 * authentication. We don't need to fix the original
1018 * header length as it will be fixed by our caller.
1019 */
1020 switch (sav->sah->saidx.dst.sa.sa_family) {
1021 #ifdef INET
1022 case AF_INET:
1023 bcopy(((caddr_t)(xd + 1)) +
1024 offsetof(struct ip, ip_len),
1025 (caddr_t) &iplen, sizeof(u_int16_t));
1026 iplen = htons(ntohs(iplen) + ahsize);
1027 m_copyback(m, offsetof(struct ip, ip_len),
1028 sizeof(u_int16_t), (caddr_t) &iplen);
1029 break;
1030 #endif /* INET */
1031
1032 #ifdef INET6
1033 case AF_INET6:
1034 bcopy(((caddr_t)(xd + 1)) +
1035 offsetof(struct ip6_hdr, ip6_plen),
1036 (caddr_t) &iplen, sizeof(uint16_t));
1037 iplen = htons(ntohs(iplen) + ahsize);
1038 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1039 sizeof(uint16_t), (caddr_t) &iplen);
1040 break;
1041 #endif /* INET6 */
1042 }
1043
1044 /* Fix the Next Header field in saved header. */
1045 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH;
1046
1047 /* Update the Next Protocol field in the IP header. */
1048 prot = IPPROTO_AH;
1049 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot);
1050
1051 /* "Massage" the packet headers for crypto processing. */
1052 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1053 skip, ahx->type, 1);
1054 if (error != 0) {
1055 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1056 free(xd, M_AH);
1057 crypto_freereq(crp);
1058 goto bad;
1059 }
1060
1061 /* Crypto operation descriptor. */
1062 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST;
1063 crp->crp_flags = CRYPTO_F_CBIFSYNC;
1064 crypto_use_mbuf(crp, m);
1065 crp->crp_callback = ah_output_cb;
1066 crp->crp_opaque = xd;
1067
1068 if (sav->flags & SADB_X_SAFLAGS_ESN && sav->replay != NULL) {
1069 SECREPLAY_LOCK(sav->replay);
1070 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT));
1071 memcpy(crp->crp_esn, &seqh, sizeof(seqh));
1072 SECREPLAY_UNLOCK(sav->replay);
1073 }
1074
1075 /* These are passed as-is to the callback. */
1076 xd->sp = sp;
1077 xd->sav = sav;
1078 xd->skip = skip;
1079 xd->idx = idx;
1080 xd->cryptoid = cryptoid;
1081 xd->vnet = curvnet;
1082
1083 if (V_async_crypto)
1084 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED));
1085 else
1086 return (crypto_dispatch(crp));
1087 bad:
1088 if (m)
1089 m_freem(m);
1090 key_freesav(&sav);
1091 key_freesp(&sp);
1092 return (error);
1093 }
1094
1095 /*
1096 * AH output callback from the crypto driver.
1097 */
1098 static int
ah_output_cb(struct cryptop * crp)1099 ah_output_cb(struct cryptop *crp)
1100 {
1101 struct xform_data *xd;
1102 struct secpolicy *sp;
1103 struct secasvar *sav;
1104 struct mbuf *m;
1105 crypto_session_t cryptoid;
1106 caddr_t ptr;
1107 u_int idx;
1108 int skip, error;
1109
1110 m = crp->crp_buf.cb_mbuf;
1111 xd = (struct xform_data *) crp->crp_opaque;
1112 CURVNET_SET(xd->vnet);
1113 sp = xd->sp;
1114 sav = xd->sav;
1115 skip = xd->skip;
1116 idx = xd->idx;
1117 cryptoid = xd->cryptoid;
1118 ptr = (caddr_t) (xd + 1);
1119
1120 /* Check for crypto errors. */
1121 if (crp->crp_etype) {
1122 if (crp->crp_etype == EAGAIN) {
1123 /* Reset the session ID */
1124 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
1125 crypto_freesession(cryptoid);
1126 xd->cryptoid = crp->crp_session;
1127 CURVNET_RESTORE();
1128 return (crypto_dispatch(crp));
1129 }
1130 AHSTAT_INC(ahs_noxform);
1131 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1132 error = crp->crp_etype;
1133 m_freem(m);
1134 goto bad;
1135 }
1136
1137 /* Shouldn't happen... */
1138 if (m == NULL) {
1139 AHSTAT_INC(ahs_crypto);
1140 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1141 error = EINVAL;
1142 goto bad;
1143 }
1144 /*
1145 * Copy original headers (with the new protocol number) back
1146 * in place.
1147 */
1148 m_copyback(m, 0, skip, ptr);
1149
1150 free(xd, M_AH);
1151 crypto_freereq(crp);
1152 AHSTAT_INC2(ahs_hist, sav->alg_auth);
1153 #ifdef REGRESSION
1154 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1155 if (V_ipsec_integrity) {
1156 int alen;
1157
1158 /*
1159 * Corrupt HMAC if we want to test integrity verification of
1160 * the other side.
1161 */
1162 alen = AUTHSIZE(sav);
1163 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1164 }
1165 #endif
1166
1167 /* NB: m is reclaimed by ipsec_process_done. */
1168 error = ipsec_process_done(m, sp, sav, idx);
1169 CURVNET_RESTORE();
1170 return (error);
1171 bad:
1172 CURVNET_RESTORE();
1173 free(xd, M_AH);
1174 crypto_freereq(crp);
1175 key_freesav(&sav);
1176 key_freesp(&sp);
1177 return (error);
1178 }
1179
1180 static struct xformsw ah_xformsw = {
1181 .xf_type = XF_AH,
1182 .xf_name = "IPsec AH",
1183 .xf_init = ah_init,
1184 .xf_cleanup = ah_cleanup,
1185 .xf_input = ah_input,
1186 .xf_output = ah_output,
1187 };
1188
1189 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1190 xform_attach, &ah_xformsw);
1191 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1192 xform_detach, &ah_xformsw);
1193