1 /* $FreeBSD$ */
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 ([email protected]),
5 * Angelos D. Keromytis ([email protected]) and
6 * Niels Provos ([email protected]).
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 static struct timeval md5warn, ripewarn, kpdkmd5warn, kpdksha1warn;
112
113 static int ah_input_cb(struct cryptop*);
114 static int ah_output_cb(struct cryptop*);
115
116 int
xform_ah_authsize(const struct auth_hash * esph)117 xform_ah_authsize(const struct auth_hash *esph)
118 {
119 int alen;
120
121 if (esph == NULL)
122 return 0;
123
124 switch (esph->type) {
125 case CRYPTO_SHA2_256_HMAC:
126 case CRYPTO_SHA2_384_HMAC:
127 case CRYPTO_SHA2_512_HMAC:
128 alen = esph->hashsize / 2; /* RFC4868 2.3 */
129 break;
130
131 case CRYPTO_AES_128_NIST_GMAC:
132 case CRYPTO_AES_192_NIST_GMAC:
133 case CRYPTO_AES_256_NIST_GMAC:
134 alen = esph->hashsize;
135 break;
136
137 default:
138 alen = AH_HMAC_HASHLEN;
139 break;
140 }
141
142 return alen;
143 }
144
145 size_t
ah_hdrsiz(struct secasvar * sav)146 ah_hdrsiz(struct secasvar *sav)
147 {
148 size_t size;
149
150 if (sav != NULL) {
151 int authsize, rplen, align;
152
153 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
154 /*XXX not right for null algorithm--does it matter??*/
155
156 /* RFC4302: use the correct alignment. */
157 align = sizeof(uint32_t);
158 #ifdef INET6
159 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) {
160 align = sizeof(uint64_t);
161 }
162 #endif
163 rplen = HDRSIZE(sav);
164 authsize = AUTHSIZE(sav);
165 size = roundup(rplen + authsize, align);
166 } else {
167 /* default guess */
168 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
169 }
170 return size;
171 }
172
173 /*
174 * NB: public for use by esp_init.
175 */
176 int
ah_init0(struct secasvar * sav,struct xformsw * xsp,struct cryptoini * cria)177 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
178 {
179 const struct auth_hash *thash;
180 int keylen;
181
182 thash = auth_algorithm_lookup(sav->alg_auth);
183 if (thash == NULL) {
184 DPRINTF(("%s: unsupported authentication algorithm %u\n",
185 __func__, sav->alg_auth));
186 return EINVAL;
187 }
188
189 switch (sav->alg_auth) {
190 case SADB_AALG_MD5HMAC:
191 if (ratecheck(&md5warn, &ipsec_warn_interval))
192 gone_in(13, "MD5-HMAC authenticator for IPsec");
193 break;
194 case SADB_X_AALG_RIPEMD160HMAC:
195 if (ratecheck(&ripewarn, &ipsec_warn_interval))
196 gone_in(13, "RIPEMD160-HMAC authenticator for IPsec");
197 break;
198 case SADB_X_AALG_MD5:
199 if (ratecheck(&kpdkmd5warn, &ipsec_warn_interval))
200 gone_in(13, "Keyed-MD5 authenticator for IPsec");
201 break;
202 case SADB_X_AALG_SHA:
203 if (ratecheck(&kpdksha1warn, &ipsec_warn_interval))
204 gone_in(13, "Keyed-SHA1 authenticator for IPsec");
205 break;
206 }
207
208 /*
209 * Verify the replay state block allocation is consistent with
210 * the protocol type. We check here so we can make assumptions
211 * later during protocol processing.
212 */
213 /* NB: replay state is setup elsewhere (sigh) */
214 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
215 DPRINTF(("%s: replay state block inconsistency, "
216 "%s algorithm %s replay state\n", __func__,
217 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
218 sav->replay == NULL ? "without" : "with"));
219 return EINVAL;
220 }
221 if (sav->key_auth == NULL) {
222 DPRINTF(("%s: no authentication key for %s algorithm\n",
223 __func__, thash->name));
224 return EINVAL;
225 }
226 keylen = _KEYLEN(sav->key_auth);
227 if (keylen > thash->keysize && thash->keysize != 0) {
228 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
229 "keysize less than %d\n", __func__,
230 keylen, thash->name, thash->keysize));
231 return EINVAL;
232 }
233
234 sav->tdb_xform = xsp;
235 sav->tdb_authalgxform = thash;
236
237 /* Initialize crypto session. */
238 bzero(cria, sizeof (*cria));
239 cria->cri_alg = sav->tdb_authalgxform->type;
240 cria->cri_klen = _KEYBITS(sav->key_auth);
241 cria->cri_key = sav->key_auth->key_data;
242 cria->cri_mlen = AUTHSIZE(sav);
243
244 return 0;
245 }
246
247 /*
248 * ah_init() is called when an SPI is being set up.
249 */
250 static int
ah_init(struct secasvar * sav,struct xformsw * xsp)251 ah_init(struct secasvar *sav, struct xformsw *xsp)
252 {
253 struct cryptoini cria;
254 int error;
255
256 error = ah_init0(sav, xsp, &cria);
257 return error ? error :
258 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
259 }
260
261 /*
262 * Paranoia.
263 *
264 * NB: public for use by esp_zeroize (XXX).
265 */
266 int
ah_zeroize(struct secasvar * sav)267 ah_zeroize(struct secasvar *sav)
268 {
269
270 if (sav->key_auth)
271 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
272
273 crypto_freesession(sav->tdb_cryptoid);
274 sav->tdb_cryptoid = NULL;
275 sav->tdb_authalgxform = NULL;
276 sav->tdb_xform = NULL;
277 return 0;
278 }
279
280 /*
281 * Massage IPv4/IPv6 headers for AH processing.
282 */
283 static int
ah_massage_headers(struct mbuf ** m0,int proto,int skip,int alg,int out)284 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
285 {
286 struct mbuf *m = *m0;
287 unsigned char *ptr;
288 int off, count;
289
290 #ifdef INET
291 struct ip *ip;
292 #endif /* INET */
293
294 #ifdef INET6
295 struct ip6_ext *ip6e;
296 struct ip6_hdr ip6;
297 int ad, alloc, nxt, noff;
298 #endif /* INET6 */
299
300 switch (proto) {
301 #ifdef INET
302 case AF_INET:
303 /*
304 * This is the least painful way of dealing with IPv4 header
305 * and option processing -- just make sure they're in
306 * contiguous memory.
307 */
308 *m0 = m = m_pullup(m, skip);
309 if (m == NULL) {
310 DPRINTF(("%s: m_pullup failed\n", __func__));
311 return ENOBUFS;
312 }
313
314 /* Fix the IP header */
315 ip = mtod(m, struct ip *);
316 if (V_ah_cleartos)
317 ip->ip_tos = 0;
318 ip->ip_ttl = 0;
319 ip->ip_sum = 0;
320
321 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
322 ip->ip_off &= htons(IP_DF);
323 else
324 ip->ip_off = htons(0);
325
326 ptr = mtod(m, unsigned char *);
327
328 /* IPv4 option processing */
329 for (off = sizeof(struct ip); off < skip;) {
330 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
331 off + 1 < skip)
332 ;
333 else {
334 DPRINTF(("%s: illegal IPv4 option length for "
335 "option %d\n", __func__, ptr[off]));
336
337 m_freem(m);
338 return EINVAL;
339 }
340
341 switch (ptr[off]) {
342 case IPOPT_EOL:
343 off = skip; /* End the loop. */
344 break;
345
346 case IPOPT_NOP:
347 off++;
348 break;
349
350 case IPOPT_SECURITY: /* 0x82 */
351 case 0x85: /* Extended security. */
352 case 0x86: /* Commercial security. */
353 case 0x94: /* Router alert */
354 case 0x95: /* RFC1770 */
355 /* Sanity check for option length. */
356 if (ptr[off + 1] < 2) {
357 DPRINTF(("%s: illegal IPv4 option "
358 "length for option %d\n",
359 __func__, ptr[off]));
360
361 m_freem(m);
362 return EINVAL;
363 }
364
365 off += ptr[off + 1];
366 break;
367
368 case IPOPT_LSRR:
369 case IPOPT_SSRR:
370 /* Sanity check for option length. */
371 if (ptr[off + 1] < 2) {
372 DPRINTF(("%s: illegal IPv4 option "
373 "length for option %d\n",
374 __func__, ptr[off]));
375
376 m_freem(m);
377 return EINVAL;
378 }
379
380 /*
381 * On output, if we have either of the
382 * source routing options, we should
383 * swap the destination address of the
384 * IP header with the last address
385 * specified in the option, as that is
386 * what the destination's IP header
387 * will look like.
388 */
389 if (out)
390 bcopy(ptr + off + ptr[off + 1] -
391 sizeof(struct in_addr),
392 &(ip->ip_dst), sizeof(struct in_addr));
393
394 /* Fall through */
395 default:
396 /* Sanity check for option length. */
397 if (ptr[off + 1] < 2) {
398 DPRINTF(("%s: illegal IPv4 option "
399 "length for option %d\n",
400 __func__, ptr[off]));
401 m_freem(m);
402 return EINVAL;
403 }
404
405 /* Zeroize all other options. */
406 count = ptr[off + 1];
407 bcopy(ipseczeroes, ptr + off, count);
408 off += count;
409 break;
410 }
411
412 /* Sanity check. */
413 if (off > skip) {
414 DPRINTF(("%s: malformed IPv4 options header\n",
415 __func__));
416
417 m_freem(m);
418 return EINVAL;
419 }
420 }
421
422 break;
423 #endif /* INET */
424
425 #ifdef INET6
426 case AF_INET6: /* Ugly... */
427 /* Copy and "cook" the IPv6 header. */
428 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
429
430 /* We don't do IPv6 Jumbograms. */
431 if (ip6.ip6_plen == 0) {
432 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
433 m_freem(m);
434 return EMSGSIZE;
435 }
436
437 ip6.ip6_flow = 0;
438 ip6.ip6_hlim = 0;
439 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
440 ip6.ip6_vfc |= IPV6_VERSION;
441
442 /* Scoped address handling. */
443 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
444 ip6.ip6_src.s6_addr16[1] = 0;
445 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
446 ip6.ip6_dst.s6_addr16[1] = 0;
447
448 /* Done with IPv6 header. */
449 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
450
451 /* Let's deal with the remaining headers (if any). */
452 if (skip - sizeof(struct ip6_hdr) > 0) {
453 if (m->m_len <= skip) {
454 ptr = (unsigned char *) malloc(
455 skip - sizeof(struct ip6_hdr),
456 M_XDATA, M_NOWAIT);
457 if (ptr == NULL) {
458 DPRINTF(("%s: failed to allocate memory"
459 "for IPv6 headers\n",__func__));
460 m_freem(m);
461 return ENOBUFS;
462 }
463
464 /*
465 * Copy all the protocol headers after
466 * the IPv6 header.
467 */
468 m_copydata(m, sizeof(struct ip6_hdr),
469 skip - sizeof(struct ip6_hdr), ptr);
470 alloc = 1;
471 } else {
472 /* No need to allocate memory. */
473 ptr = mtod(m, unsigned char *) +
474 sizeof(struct ip6_hdr);
475 alloc = 0;
476 }
477 } else
478 break;
479
480 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
481
482 for (off = 0; off < skip - sizeof(struct ip6_hdr);)
483 switch (nxt) {
484 case IPPROTO_HOPOPTS:
485 case IPPROTO_DSTOPTS:
486 ip6e = (struct ip6_ext *)(ptr + off);
487 noff = off + ((ip6e->ip6e_len + 1) << 3);
488
489 /* Sanity check. */
490 if (noff > skip - sizeof(struct ip6_hdr))
491 goto error6;
492
493 /*
494 * Zero out mutable options.
495 */
496 for (count = off + sizeof(struct ip6_ext);
497 count < noff;) {
498 if (ptr[count] == IP6OPT_PAD1) {
499 count++;
500 continue; /* Skip padding. */
501 }
502
503 ad = ptr[count + 1] + 2;
504 if (count + ad > noff)
505 goto error6;
506
507 if (ptr[count] & IP6OPT_MUTABLE)
508 memset(ptr + count, 0, ad);
509 count += ad;
510 }
511
512 if (count != noff)
513 goto error6;
514
515 /* Advance. */
516 off += ((ip6e->ip6e_len + 1) << 3);
517 nxt = ip6e->ip6e_nxt;
518 break;
519
520 case IPPROTO_ROUTING:
521 /*
522 * Always include routing headers in
523 * computation.
524 */
525 ip6e = (struct ip6_ext *) (ptr + off);
526 off += ((ip6e->ip6e_len + 1) << 3);
527 nxt = ip6e->ip6e_nxt;
528 break;
529
530 default:
531 DPRINTF(("%s: unexpected IPv6 header type %d",
532 __func__, off));
533 error6:
534 if (alloc)
535 free(ptr, M_XDATA);
536 m_freem(m);
537 return EINVAL;
538 }
539
540 /* Copyback and free, if we allocated. */
541 if (alloc) {
542 m_copyback(m, sizeof(struct ip6_hdr),
543 skip - sizeof(struct ip6_hdr), ptr);
544 free(ptr, M_XDATA);
545 }
546
547 break;
548 #endif /* INET6 */
549 }
550
551 return 0;
552 }
553
554 /*
555 * ah_input() gets called to verify that an input packet
556 * passes authentication.
557 */
558 static int
ah_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)559 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
560 {
561 IPSEC_DEBUG_DECLARE(char buf[128]);
562 const struct auth_hash *ahx;
563 struct cryptodesc *crda;
564 struct cryptop *crp;
565 struct xform_data *xd;
566 struct newah *ah;
567 crypto_session_t cryptoid;
568 int hl, rplen, authsize, ahsize, error;
569
570 IPSEC_ASSERT(sav != NULL, ("null SA"));
571 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
572 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
573 ("null authentication xform"));
574
575 /* Figure out header size. */
576 rplen = HDRSIZE(sav);
577
578 /* XXX don't pullup, just copy header */
579 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
580 if (ah == NULL) {
581 DPRINTF(("ah_input: cannot pullup header\n"));
582 AHSTAT_INC(ahs_hdrops); /*XXX*/
583 error = ENOBUFS;
584 goto bad;
585 }
586
587 /* Check replay window, if applicable. */
588 SECASVAR_LOCK(sav);
589 if (sav->replay != NULL && sav->replay->wsize != 0 &&
590 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) {
591 SECASVAR_UNLOCK(sav);
592 AHSTAT_INC(ahs_replay);
593 DPRINTF(("%s: packet replay failure: %s\n", __func__,
594 ipsec_sa2str(sav, buf, sizeof(buf))));
595 error = EACCES;
596 goto bad;
597 }
598 cryptoid = sav->tdb_cryptoid;
599 SECASVAR_UNLOCK(sav);
600
601 /* Verify AH header length. */
602 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t));
603 ahx = sav->tdb_authalgxform;
604 authsize = AUTHSIZE(sav);
605 ahsize = ah_hdrsiz(sav);
606 if (hl != ahsize) {
607 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
608 " for packet in SA %s/%08lx\n", __func__, hl,
609 (u_long)ahsize,
610 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
611 (u_long) ntohl(sav->spi)));
612 AHSTAT_INC(ahs_badauthl);
613 error = EACCES;
614 goto bad;
615 }
616 if (skip + ahsize > m->m_pkthdr.len) {
617 DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
618 " for packet in SA %s/%08lx\n", __func__,
619 m->m_pkthdr.len, (u_long)(skip + ahsize),
620 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
621 (u_long) ntohl(sav->spi)));
622 AHSTAT_INC(ahs_badauthl);
623 error = EACCES;
624 goto bad;
625 }
626 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
627
628 /* Get crypto descriptors. */
629 crp = crypto_getreq(1);
630 if (crp == NULL) {
631 DPRINTF(("%s: failed to acquire crypto descriptor\n",
632 __func__));
633 AHSTAT_INC(ahs_crypto);
634 error = ENOBUFS;
635 goto bad;
636 }
637
638 crda = crp->crp_desc;
639 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
640
641 crda->crd_skip = 0;
642 crda->crd_len = m->m_pkthdr.len;
643 crda->crd_inject = skip + rplen;
644
645 /* Authentication operation. */
646 crda->crd_alg = ahx->type;
647 crda->crd_klen = _KEYBITS(sav->key_auth);
648 crda->crd_key = sav->key_auth->key_data;
649
650 /* Allocate IPsec-specific opaque crypto info. */
651 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA,
652 M_NOWAIT | M_ZERO);
653 if (xd == NULL) {
654 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
655 AHSTAT_INC(ahs_crypto);
656 crypto_freereq(crp);
657 error = ENOBUFS;
658 goto bad;
659 }
660
661 /*
662 * Save the authenticator, the skipped portion of the packet,
663 * and the AH header.
664 */
665 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1));
666
667 /* Zeroize the authenticator on the packet. */
668 m_copyback(m, skip + rplen, authsize, ipseczeroes);
669
670 /* Save ah_nxt, since ah pointer can become invalid after "massage" */
671 hl = ah->ah_nxt;
672
673 /* "Massage" the packet headers for crypto processing. */
674 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
675 skip, ahx->type, 0);
676 if (error != 0) {
677 /* NB: mbuf is free'd by ah_massage_headers */
678 AHSTAT_INC(ahs_hdrops);
679 free(xd, M_XDATA);
680 crypto_freereq(crp);
681 key_freesav(&sav);
682 return (error);
683 }
684
685 /* Crypto operation descriptor. */
686 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
687 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
688 if (V_async_crypto)
689 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
690 crp->crp_buf = (caddr_t) m;
691 crp->crp_callback = ah_input_cb;
692 crp->crp_session = cryptoid;
693 crp->crp_opaque = (caddr_t) xd;
694
695 /* These are passed as-is to the callback. */
696 xd->sav = sav;
697 xd->nxt = hl;
698 xd->protoff = protoff;
699 xd->skip = skip;
700 xd->cryptoid = cryptoid;
701 xd->vnet = curvnet;
702 return (crypto_dispatch(crp));
703 bad:
704 m_freem(m);
705 key_freesav(&sav);
706 return (error);
707 }
708
709 /*
710 * AH input callback from the crypto driver.
711 */
712 static int
ah_input_cb(struct cryptop * crp)713 ah_input_cb(struct cryptop *crp)
714 {
715 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
716 unsigned char calc[AH_ALEN_MAX];
717 struct mbuf *m;
718 struct xform_data *xd;
719 struct secasvar *sav;
720 struct secasindex *saidx;
721 caddr_t ptr;
722 crypto_session_t cryptoid;
723 int authsize, rplen, ahsize, error, skip, protoff;
724 uint8_t nxt;
725
726 m = (struct mbuf *) crp->crp_buf;
727 xd = (struct xform_data *) crp->crp_opaque;
728 CURVNET_SET(xd->vnet);
729 sav = xd->sav;
730 skip = xd->skip;
731 nxt = xd->nxt;
732 protoff = xd->protoff;
733 cryptoid = xd->cryptoid;
734 saidx = &sav->sah->saidx;
735 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
736 saidx->dst.sa.sa_family == AF_INET6,
737 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
738
739 /* Check for crypto errors. */
740 if (crp->crp_etype) {
741 if (crp->crp_etype == EAGAIN) {
742 /* Reset the session ID */
743 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
744 crypto_freesession(cryptoid);
745 xd->cryptoid = crp->crp_session;
746 CURVNET_RESTORE();
747 return (crypto_dispatch(crp));
748 }
749 AHSTAT_INC(ahs_noxform);
750 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
751 error = crp->crp_etype;
752 goto bad;
753 } else {
754 AHSTAT_INC(ahs_hist[sav->alg_auth]);
755 crypto_freereq(crp); /* No longer needed. */
756 crp = NULL;
757 }
758
759 /* Shouldn't happen... */
760 if (m == NULL) {
761 AHSTAT_INC(ahs_crypto);
762 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
763 error = EINVAL;
764 goto bad;
765 }
766
767 /* Figure out header size. */
768 rplen = HDRSIZE(sav);
769 authsize = AUTHSIZE(sav);
770 ahsize = ah_hdrsiz(sav);
771
772 /* Copy authenticator off the packet. */
773 m_copydata(m, skip + rplen, authsize, calc);
774
775 /* Verify authenticator. */
776 ptr = (caddr_t) (xd + 1);
777 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
778 DPRINTF(("%s: authentication hash mismatch for packet "
779 "in SA %s/%08lx\n", __func__,
780 ipsec_address(&saidx->dst, buf, sizeof(buf)),
781 (u_long) ntohl(sav->spi)));
782 AHSTAT_INC(ahs_badauth);
783 error = EACCES;
784 goto bad;
785 }
786 /* Fix the Next Protocol field. */
787 ((uint8_t *) ptr)[protoff] = nxt;
788
789 /* Copyback the saved (uncooked) network headers. */
790 m_copyback(m, 0, skip, ptr);
791 free(xd, M_XDATA), xd = NULL; /* No longer needed */
792
793 /*
794 * Header is now authenticated.
795 */
796 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
797
798 /*
799 * Update replay sequence number, if appropriate.
800 */
801 if (sav->replay) {
802 u_int32_t seq;
803
804 m_copydata(m, skip + offsetof(struct newah, ah_seq),
805 sizeof (seq), (caddr_t) &seq);
806 SECASVAR_LOCK(sav);
807 if (ipsec_updatereplay(ntohl(seq), sav)) {
808 SECASVAR_UNLOCK(sav);
809 AHSTAT_INC(ahs_replay);
810 error = EACCES;
811 goto bad;
812 }
813 SECASVAR_UNLOCK(sav);
814 }
815
816 /*
817 * Remove the AH header and authenticator from the mbuf.
818 */
819 error = m_striphdr(m, skip, ahsize);
820 if (error) {
821 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
822 ipsec_address(&saidx->dst, buf, sizeof(buf)),
823 (u_long) ntohl(sav->spi)));
824 AHSTAT_INC(ahs_hdrops);
825 goto bad;
826 }
827
828 switch (saidx->dst.sa.sa_family) {
829 #ifdef INET6
830 case AF_INET6:
831 error = ipsec6_common_input_cb(m, sav, skip, protoff);
832 break;
833 #endif
834 #ifdef INET
835 case AF_INET:
836 error = ipsec4_common_input_cb(m, sav, skip, protoff);
837 break;
838 #endif
839 default:
840 panic("%s: Unexpected address family: %d saidx=%p", __func__,
841 saidx->dst.sa.sa_family, saidx);
842 }
843 CURVNET_RESTORE();
844 return error;
845 bad:
846 CURVNET_RESTORE();
847 if (sav)
848 key_freesav(&sav);
849 if (m != NULL)
850 m_freem(m);
851 if (xd != NULL)
852 free(xd, M_XDATA);
853 if (crp != NULL)
854 crypto_freereq(crp);
855 return error;
856 }
857
858 /*
859 * AH output routine, called by ipsec[46]_perform_request().
860 */
861 static int
ah_output(struct mbuf * m,struct secpolicy * sp,struct secasvar * sav,u_int idx,int skip,int protoff)862 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
863 u_int idx, int skip, int protoff)
864 {
865 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
866 const struct auth_hash *ahx;
867 struct cryptodesc *crda;
868 struct xform_data *xd;
869 struct mbuf *mi;
870 struct cryptop *crp;
871 struct newah *ah;
872 crypto_session_t cryptoid;
873 uint16_t iplen;
874 int error, rplen, authsize, ahsize, maxpacketsize, roff;
875 uint8_t prot;
876
877 IPSEC_ASSERT(sav != NULL, ("null SA"));
878 ahx = sav->tdb_authalgxform;
879 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
880
881 AHSTAT_INC(ahs_output);
882
883 /* Figure out header size. */
884 rplen = HDRSIZE(sav);
885 authsize = AUTHSIZE(sav);
886 ahsize = ah_hdrsiz(sav);
887
888 /* Check for maximum packet size violations. */
889 switch (sav->sah->saidx.dst.sa.sa_family) {
890 #ifdef INET
891 case AF_INET:
892 maxpacketsize = IP_MAXPACKET;
893 break;
894 #endif /* INET */
895 #ifdef INET6
896 case AF_INET6:
897 maxpacketsize = IPV6_MAXPACKET;
898 break;
899 #endif /* INET6 */
900 default:
901 DPRINTF(("%s: unknown/unsupported protocol family %u, "
902 "SA %s/%08lx\n", __func__,
903 sav->sah->saidx.dst.sa.sa_family,
904 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
905 (u_long) ntohl(sav->spi)));
906 AHSTAT_INC(ahs_nopf);
907 error = EPFNOSUPPORT;
908 goto bad;
909 }
910 if (ahsize + m->m_pkthdr.len > maxpacketsize) {
911 DPRINTF(("%s: packet in SA %s/%08lx got too big "
912 "(len %u, max len %u)\n", __func__,
913 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
914 (u_long) ntohl(sav->spi),
915 ahsize + m->m_pkthdr.len, maxpacketsize));
916 AHSTAT_INC(ahs_toobig);
917 error = EMSGSIZE;
918 goto bad;
919 }
920
921 /* Update the counters. */
922 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
923
924 m = m_unshare(m, M_NOWAIT);
925 if (m == NULL) {
926 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
927 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
928 (u_long) ntohl(sav->spi)));
929 AHSTAT_INC(ahs_hdrops);
930 error = ENOBUFS;
931 goto bad;
932 }
933
934 /* Inject AH header. */
935 mi = m_makespace(m, skip, ahsize, &roff);
936 if (mi == NULL) {
937 DPRINTF(("%s: failed to inject %u byte AH header for SA "
938 "%s/%08lx\n", __func__, ahsize,
939 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
940 (u_long) ntohl(sav->spi)));
941 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
942 error = ENOBUFS;
943 goto bad;
944 }
945
946 /*
947 * The AH header is guaranteed by m_makespace() to be in
948 * contiguous memory, at roff bytes offset into the returned mbuf.
949 */
950 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
951
952 /* Initialize the AH header. */
953 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
954 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t);
955 ah->ah_reserve = 0;
956 ah->ah_spi = sav->spi;
957
958 /* Zeroize authenticator. */
959 m_copyback(m, skip + rplen, authsize, ipseczeroes);
960
961 /* Zeroize padding */
962 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize),
963 ipseczeroes);
964
965 /* Insert packet replay counter, as requested. */
966 SECASVAR_LOCK(sav);
967 if (sav->replay) {
968 if (sav->replay->count == ~0 &&
969 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
970 SECASVAR_UNLOCK(sav);
971 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
972 __func__, ipsec_address(&sav->sah->saidx.dst, buf,
973 sizeof(buf)), (u_long) ntohl(sav->spi)));
974 AHSTAT_INC(ahs_wrap);
975 error = EACCES;
976 goto bad;
977 }
978 #ifdef REGRESSION
979 /* Emulate replay attack when ipsec_replay is TRUE. */
980 if (!V_ipsec_replay)
981 #endif
982 sav->replay->count++;
983 ah->ah_seq = htonl(sav->replay->count);
984 }
985 cryptoid = sav->tdb_cryptoid;
986 SECASVAR_UNLOCK(sav);
987
988 /* Get crypto descriptors. */
989 crp = crypto_getreq(1);
990 if (crp == NULL) {
991 DPRINTF(("%s: failed to acquire crypto descriptors\n",
992 __func__));
993 AHSTAT_INC(ahs_crypto);
994 error = ENOBUFS;
995 goto bad;
996 }
997
998 crda = crp->crp_desc;
999 crda->crd_skip = 0;
1000 crda->crd_inject = skip + rplen;
1001 crda->crd_len = m->m_pkthdr.len;
1002
1003 /* Authentication operation. */
1004 crda->crd_alg = ahx->type;
1005 crda->crd_key = sav->key_auth->key_data;
1006 crda->crd_klen = _KEYBITS(sav->key_auth);
1007
1008 /* Allocate IPsec-specific opaque crypto info. */
1009 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA,
1010 M_NOWAIT | M_ZERO);
1011 if (xd == NULL) {
1012 crypto_freereq(crp);
1013 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
1014 AHSTAT_INC(ahs_crypto);
1015 error = ENOBUFS;
1016 goto bad;
1017 }
1018
1019 /* Save the skipped portion of the packet. */
1020 m_copydata(m, 0, skip, (caddr_t) (xd + 1));
1021
1022 /*
1023 * Fix IP header length on the header used for
1024 * authentication. We don't need to fix the original
1025 * header length as it will be fixed by our caller.
1026 */
1027 switch (sav->sah->saidx.dst.sa.sa_family) {
1028 #ifdef INET
1029 case AF_INET:
1030 bcopy(((caddr_t)(xd + 1)) +
1031 offsetof(struct ip, ip_len),
1032 (caddr_t) &iplen, sizeof(u_int16_t));
1033 iplen = htons(ntohs(iplen) + ahsize);
1034 m_copyback(m, offsetof(struct ip, ip_len),
1035 sizeof(u_int16_t), (caddr_t) &iplen);
1036 break;
1037 #endif /* INET */
1038
1039 #ifdef INET6
1040 case AF_INET6:
1041 bcopy(((caddr_t)(xd + 1)) +
1042 offsetof(struct ip6_hdr, ip6_plen),
1043 (caddr_t) &iplen, sizeof(uint16_t));
1044 iplen = htons(ntohs(iplen) + ahsize);
1045 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1046 sizeof(uint16_t), (caddr_t) &iplen);
1047 break;
1048 #endif /* INET6 */
1049 }
1050
1051 /* Fix the Next Header field in saved header. */
1052 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH;
1053
1054 /* Update the Next Protocol field in the IP header. */
1055 prot = IPPROTO_AH;
1056 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot);
1057
1058 /* "Massage" the packet headers for crypto processing. */
1059 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1060 skip, ahx->type, 1);
1061 if (error != 0) {
1062 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1063 free(xd, M_XDATA);
1064 crypto_freereq(crp);
1065 goto bad;
1066 }
1067
1068 /* Crypto operation descriptor. */
1069 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1070 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
1071 if (V_async_crypto)
1072 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
1073 crp->crp_buf = (caddr_t) m;
1074 crp->crp_callback = ah_output_cb;
1075 crp->crp_session = cryptoid;
1076 crp->crp_opaque = (caddr_t) xd;
1077
1078 /* These are passed as-is to the callback. */
1079 xd->sp = sp;
1080 xd->sav = sav;
1081 xd->skip = skip;
1082 xd->idx = idx;
1083 xd->cryptoid = cryptoid;
1084 xd->vnet = curvnet;
1085
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 = (struct mbuf *) crp->crp_buf;
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_XDATA);
1151 crypto_freereq(crp);
1152 AHSTAT_INC(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_XDATA);
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_zeroize = ah_zeroize,
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