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 #include "opt_ipsec.h"
42
43 #include <sys/param.h>
44 #include <sys/systm.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 unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
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_NIST_GMAC:
132 alen = esph->hashsize;
133 break;
134
135 default:
136 alen = AH_HMAC_HASHLEN;
137 break;
138 }
139
140 return alen;
141 }
142
143 size_t
ah_hdrsiz(struct secasvar * sav)144 ah_hdrsiz(struct secasvar *sav)
145 {
146 size_t size;
147
148 if (sav != NULL) {
149 int authsize, rplen, align;
150
151 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
152 /*XXX not right for null algorithm--does it matter??*/
153
154 /* RFC4302: use the correct alignment. */
155 align = sizeof(uint32_t);
156 #ifdef INET6
157 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) {
158 align = sizeof(uint64_t);
159 }
160 #endif
161 rplen = HDRSIZE(sav);
162 authsize = AUTHSIZE(sav);
163 size = roundup(rplen + authsize, align);
164 } else {
165 /* default guess */
166 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
167 }
168 return size;
169 }
170
171 /*
172 * NB: public for use by esp_init.
173 */
174 int
ah_init0(struct secasvar * sav,struct xformsw * xsp,struct crypto_session_params * csp)175 ah_init0(struct secasvar *sav, struct xformsw *xsp,
176 struct crypto_session_params *csp)
177 {
178 const struct auth_hash *thash;
179 int keylen;
180
181 thash = auth_algorithm_lookup(sav->alg_auth);
182 if (thash == NULL) {
183 DPRINTF(("%s: unsupported authentication algorithm %u\n",
184 __func__, sav->alg_auth));
185 return EINVAL;
186 }
187
188 /*
189 * Verify the replay state block allocation is consistent with
190 * the protocol type. We check here so we can make assumptions
191 * later during protocol processing.
192 */
193 /* NB: replay state is setup elsewhere (sigh) */
194 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
195 DPRINTF(("%s: replay state block inconsistency, "
196 "%s algorithm %s replay state\n", __func__,
197 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
198 sav->replay == NULL ? "without" : "with"));
199 return EINVAL;
200 }
201 if (sav->key_auth == NULL) {
202 DPRINTF(("%s: no authentication key for %s algorithm\n",
203 __func__, thash->name));
204 return EINVAL;
205 }
206 keylen = _KEYLEN(sav->key_auth);
207 if (keylen > thash->keysize && thash->keysize != 0) {
208 DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
209 "keysize less than %d\n", __func__,
210 keylen, thash->name, thash->keysize));
211 return EINVAL;
212 }
213
214 sav->tdb_xform = xsp;
215 sav->tdb_authalgxform = thash;
216
217 /* Initialize crypto session. */
218 csp->csp_auth_alg = sav->tdb_authalgxform->type;
219 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) {
220 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8;
221 csp->csp_auth_key = sav->key_auth->key_data;
222 };
223 csp->csp_auth_mlen = AUTHSIZE(sav);
224
225 return 0;
226 }
227
228 /*
229 * ah_init() is called when an SPI is being set up.
230 */
231 static int
ah_init(struct secasvar * sav,struct xformsw * xsp)232 ah_init(struct secasvar *sav, struct xformsw *xsp)
233 {
234 struct crypto_session_params csp;
235 int error;
236
237 memset(&csp, 0, sizeof(csp));
238 csp.csp_mode = CSP_MODE_DIGEST;
239
240 if (sav->flags & SADB_X_SAFLAGS_ESN)
241 csp.csp_flags |= CSP_F_ESN;
242
243 error = ah_init0(sav, xsp, &csp);
244 return error ? error :
245 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
246 }
247
248 static void
ah_cleanup(struct secasvar * sav)249 ah_cleanup(struct secasvar *sav)
250 {
251
252 crypto_freesession(sav->tdb_cryptoid);
253 sav->tdb_cryptoid = NULL;
254 sav->tdb_authalgxform = NULL;
255 }
256
257 /*
258 * Massage IPv4/IPv6 headers for AH processing.
259 */
260 static int
ah_massage_headers(struct mbuf ** m0,int proto,int skip,int alg,int out)261 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
262 {
263 struct mbuf *m = *m0;
264 unsigned char *ptr;
265 int off, count;
266
267 #ifdef INET
268 struct ip *ip;
269 #endif /* INET */
270
271 #ifdef INET6
272 struct ip6_ext *ip6e;
273 struct ip6_hdr ip6;
274 int ad, alloc, nxt, noff;
275 #endif /* INET6 */
276
277 switch (proto) {
278 #ifdef INET
279 case AF_INET:
280 /*
281 * This is the least painful way of dealing with IPv4 header
282 * and option processing -- just make sure they're in
283 * contiguous memory.
284 */
285 *m0 = m = m_pullup(m, skip);
286 if (m == NULL) {
287 DPRINTF(("%s: m_pullup failed\n", __func__));
288 return ENOBUFS;
289 }
290
291 /* Fix the IP header */
292 ip = mtod(m, struct ip *);
293 if (V_ah_cleartos)
294 ip->ip_tos = 0;
295 ip->ip_ttl = 0;
296 ip->ip_sum = 0;
297 ip->ip_off = htons(0);
298
299 ptr = mtod(m, unsigned char *);
300
301 /* IPv4 option processing */
302 for (off = sizeof(struct ip); off < skip;) {
303 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
304 off + 1 < skip)
305 ;
306 else {
307 DPRINTF(("%s: illegal IPv4 option length for "
308 "option %d\n", __func__, ptr[off]));
309
310 m_freem(m);
311 return EINVAL;
312 }
313
314 switch (ptr[off]) {
315 case IPOPT_EOL:
316 off = skip; /* End the loop. */
317 break;
318
319 case IPOPT_NOP:
320 off++;
321 break;
322
323 case IPOPT_SECURITY: /* 0x82 */
324 case 0x85: /* Extended security. */
325 case 0x86: /* Commercial security. */
326 case 0x94: /* Router alert */
327 case 0x95: /* RFC1770 */
328 /* Sanity check for option length. */
329 if (ptr[off + 1] < 2) {
330 DPRINTF(("%s: illegal IPv4 option "
331 "length for option %d\n",
332 __func__, ptr[off]));
333
334 m_freem(m);
335 return EINVAL;
336 }
337
338 off += ptr[off + 1];
339 break;
340
341 case IPOPT_LSRR:
342 case IPOPT_SSRR:
343 /* Sanity check for option length. */
344 if (ptr[off + 1] < 2) {
345 DPRINTF(("%s: illegal IPv4 option "
346 "length for option %d\n",
347 __func__, ptr[off]));
348
349 m_freem(m);
350 return EINVAL;
351 }
352
353 /*
354 * On output, if we have either of the
355 * source routing options, we should
356 * swap the destination address of the
357 * IP header with the last address
358 * specified in the option, as that is
359 * what the destination's IP header
360 * will look like.
361 */
362 if (out)
363 bcopy(ptr + off + ptr[off + 1] -
364 sizeof(struct in_addr),
365 &(ip->ip_dst), sizeof(struct in_addr));
366
367 /* Fall through */
368 default:
369 /* Sanity check for option length. */
370 if (ptr[off + 1] < 2) {
371 DPRINTF(("%s: illegal IPv4 option "
372 "length for option %d\n",
373 __func__, ptr[off]));
374 m_freem(m);
375 return EINVAL;
376 }
377
378 /* Zeroize all other options. */
379 count = ptr[off + 1];
380 bcopy(ipseczeroes, ptr + off, count);
381 off += count;
382 break;
383 }
384
385 /* Sanity check. */
386 if (off > skip) {
387 DPRINTF(("%s: malformed IPv4 options header\n",
388 __func__));
389
390 m_freem(m);
391 return EINVAL;
392 }
393 }
394
395 break;
396 #endif /* INET */
397
398 #ifdef INET6
399 case AF_INET6: /* Ugly... */
400 /* Copy and "cook" the IPv6 header. */
401 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
402
403 /* We don't do IPv6 Jumbograms. */
404 if (ip6.ip6_plen == 0) {
405 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
406 m_freem(m);
407 return EMSGSIZE;
408 }
409
410 ip6.ip6_flow = 0;
411 ip6.ip6_hlim = 0;
412 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
413 ip6.ip6_vfc |= IPV6_VERSION;
414
415 /* Scoped address handling. */
416 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
417 ip6.ip6_src.s6_addr16[1] = 0;
418 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
419 ip6.ip6_dst.s6_addr16[1] = 0;
420
421 /* Done with IPv6 header. */
422 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
423
424 /* Let's deal with the remaining headers (if any). */
425 if (skip - sizeof(struct ip6_hdr) > 0) {
426 if (m->m_len <= skip) {
427 ptr = (unsigned char *) malloc(
428 skip - sizeof(struct ip6_hdr),
429 M_XDATA, M_NOWAIT);
430 if (ptr == NULL) {
431 DPRINTF(("%s: failed to allocate memory"
432 "for IPv6 headers\n",__func__));
433 m_freem(m);
434 return ENOBUFS;
435 }
436
437 /*
438 * Copy all the protocol headers after
439 * the IPv6 header.
440 */
441 m_copydata(m, sizeof(struct ip6_hdr),
442 skip - sizeof(struct ip6_hdr), ptr);
443 alloc = 1;
444 } else {
445 /* No need to allocate memory. */
446 ptr = mtod(m, unsigned char *) +
447 sizeof(struct ip6_hdr);
448 alloc = 0;
449 }
450 } else
451 break;
452
453 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
454
455 for (off = 0; off < skip - sizeof(struct ip6_hdr);)
456 switch (nxt) {
457 case IPPROTO_HOPOPTS:
458 case IPPROTO_DSTOPTS:
459 ip6e = (struct ip6_ext *)(ptr + off);
460 noff = off + ((ip6e->ip6e_len + 1) << 3);
461
462 /* Sanity check. */
463 if (noff > skip - sizeof(struct ip6_hdr))
464 goto error6;
465
466 /*
467 * Zero out mutable options.
468 */
469 for (count = off + sizeof(struct ip6_ext);
470 count < noff;) {
471 if (ptr[count] == IP6OPT_PAD1) {
472 count++;
473 continue; /* Skip padding. */
474 }
475
476 ad = ptr[count + 1] + 2;
477 if (count + ad > noff)
478 goto error6;
479
480 if (ptr[count] & IP6OPT_MUTABLE)
481 memset(ptr + count, 0, ad);
482 count += ad;
483 }
484
485 if (count != noff)
486 goto error6;
487
488 /* Advance. */
489 off += ((ip6e->ip6e_len + 1) << 3);
490 nxt = ip6e->ip6e_nxt;
491 break;
492
493 case IPPROTO_ROUTING:
494 /*
495 * Always include routing headers in
496 * computation.
497 */
498 ip6e = (struct ip6_ext *) (ptr + off);
499 off += ((ip6e->ip6e_len + 1) << 3);
500 nxt = ip6e->ip6e_nxt;
501 break;
502
503 default:
504 DPRINTF(("%s: unexpected IPv6 header type %d",
505 __func__, off));
506 error6:
507 if (alloc)
508 free(ptr, M_XDATA);
509 m_freem(m);
510 return EINVAL;
511 }
512
513 /* Copyback and free, if we allocated. */
514 if (alloc) {
515 m_copyback(m, sizeof(struct ip6_hdr),
516 skip - sizeof(struct ip6_hdr), ptr);
517 free(ptr, M_XDATA);
518 }
519
520 break;
521 #endif /* INET6 */
522 }
523
524 return 0;
525 }
526
527 /*
528 * ah_input() gets called to verify that an input packet
529 * passes authentication.
530 */
531 static int
ah_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)532 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
533 {
534 IPSEC_DEBUG_DECLARE(char buf[128]);
535 const struct auth_hash *ahx;
536 struct cryptop *crp;
537 struct xform_data *xd;
538 struct newah *ah;
539 crypto_session_t cryptoid;
540 int hl, rplen, authsize, ahsize, error;
541 uint32_t seqh;
542
543 IPSEC_ASSERT(sav != NULL, ("null SA"));
544 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
545 IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
546 ("null authentication xform"));
547
548 /* Figure out header size. */
549 rplen = HDRSIZE(sav);
550
551 if (m->m_len < skip + rplen) {
552 m = m_pullup(m, skip + rplen);
553 if (m == NULL) {
554 DPRINTF(("ah_input: cannot pullup header\n"));
555 AHSTAT_INC(ahs_hdrops); /*XXX*/
556 error = ENOBUFS;
557 goto bad;
558 }
559 }
560 ah = (struct newah *)(mtod(m, caddr_t) + skip);
561
562 /* Check replay window, if applicable. */
563 SECASVAR_LOCK(sav);
564 if (sav->replay != NULL && sav->replay->wsize != 0 &&
565 ipsec_chkreplay(ntohl(ah->ah_seq), &seqh, sav) == 0) {
566 SECASVAR_UNLOCK(sav);
567 AHSTAT_INC(ahs_replay);
568 DPRINTF(("%s: packet replay failure: %s\n", __func__,
569 ipsec_sa2str(sav, buf, sizeof(buf))));
570 error = EACCES;
571 goto bad;
572 }
573 cryptoid = sav->tdb_cryptoid;
574 SECASVAR_UNLOCK(sav);
575
576 /* Verify AH header length. */
577 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t));
578 ahx = sav->tdb_authalgxform;
579 authsize = AUTHSIZE(sav);
580 ahsize = ah_hdrsiz(sav);
581 if (hl != ahsize) {
582 DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
583 " for packet in SA %s/%08lx\n", __func__, hl,
584 (u_long)ahsize,
585 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
586 (u_long) ntohl(sav->spi)));
587 AHSTAT_INC(ahs_badauthl);
588 error = EACCES;
589 goto bad;
590 }
591 if (skip + ahsize > m->m_pkthdr.len) {
592 DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
593 " for packet in SA %s/%08lx\n", __func__,
594 m->m_pkthdr.len, (u_long)(skip + ahsize),
595 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
596 (u_long) ntohl(sav->spi)));
597 AHSTAT_INC(ahs_badauthl);
598 error = EACCES;
599 goto bad;
600 }
601 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
602
603 /* Get crypto descriptors. */
604 crp = crypto_getreq(cryptoid, M_NOWAIT);
605 if (crp == NULL) {
606 DPRINTF(("%s: failed to acquire crypto descriptor\n",
607 __func__));
608 AHSTAT_INC(ahs_crypto);
609 error = ENOBUFS;
610 goto bad;
611 }
612
613 crp->crp_payload_start = 0;
614 crp->crp_payload_length = m->m_pkthdr.len;
615 crp->crp_digest_start = skip + rplen;
616
617 /* Allocate IPsec-specific opaque crypto info. */
618 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA,
619 M_NOWAIT | M_ZERO);
620 if (xd == NULL) {
621 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
622 AHSTAT_INC(ahs_crypto);
623 crypto_freereq(crp);
624 error = ENOBUFS;
625 goto bad;
626 }
627
628 /*
629 * Save the authenticator, the skipped portion of the packet,
630 * and the AH header.
631 */
632 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1));
633
634 /* Zeroize the authenticator on the packet. */
635 m_copyback(m, skip + rplen, authsize, ipseczeroes);
636
637 /* Save ah_nxt, since ah pointer can become invalid after "massage" */
638 hl = ah->ah_nxt;
639
640 /* "Massage" the packet headers for crypto processing. */
641 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
642 skip, ahx->type, 0);
643 if (error != 0) {
644 /* NB: mbuf is free'd by ah_massage_headers */
645 AHSTAT_INC(ahs_hdrops);
646 free(xd, M_XDATA);
647 crypto_freereq(crp);
648 key_freesav(&sav);
649 return (error);
650 }
651
652 /* Crypto operation descriptor. */
653 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST;
654 crp->crp_flags = CRYPTO_F_CBIFSYNC;
655 if (V_async_crypto)
656 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
657 crypto_use_mbuf(crp, m);
658 crp->crp_callback = ah_input_cb;
659 crp->crp_opaque = xd;
660
661 if (sav->flags & SADB_X_SAFLAGS_ESN &&
662 sav->replay != NULL && sav->replay->wsize != 0) {
663 seqh = htonl(seqh);
664 memcpy(crp->crp_esn, &seqh, sizeof(seqh));
665 }
666
667 /* These are passed as-is to the callback. */
668 xd->sav = sav;
669 xd->nxt = hl;
670 xd->protoff = protoff;
671 xd->skip = skip;
672 xd->cryptoid = cryptoid;
673 xd->vnet = curvnet;
674 return (crypto_dispatch(crp));
675 bad:
676 m_freem(m);
677 key_freesav(&sav);
678 return (error);
679 }
680
681 /*
682 * AH input callback from the crypto driver.
683 */
684 static int
ah_input_cb(struct cryptop * crp)685 ah_input_cb(struct cryptop *crp)
686 {
687 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
688 unsigned char calc[AH_ALEN_MAX];
689 struct mbuf *m;
690 struct xform_data *xd;
691 struct secasvar *sav;
692 struct secasindex *saidx;
693 caddr_t ptr;
694 crypto_session_t cryptoid;
695 int authsize, rplen, ahsize, error, skip, protoff;
696 uint8_t nxt;
697
698 m = crp->crp_buf.cb_mbuf;
699 xd = crp->crp_opaque;
700 CURVNET_SET(xd->vnet);
701 sav = xd->sav;
702 skip = xd->skip;
703 nxt = xd->nxt;
704 protoff = xd->protoff;
705 cryptoid = xd->cryptoid;
706 saidx = &sav->sah->saidx;
707 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
708 saidx->dst.sa.sa_family == AF_INET6,
709 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
710
711 /* Check for crypto errors. */
712 if (crp->crp_etype) {
713 if (crp->crp_etype == EAGAIN) {
714 /* Reset the session ID */
715 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
716 crypto_freesession(cryptoid);
717 xd->cryptoid = crp->crp_session;
718 CURVNET_RESTORE();
719 return (crypto_dispatch(crp));
720 }
721 AHSTAT_INC(ahs_noxform);
722 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
723 error = crp->crp_etype;
724 goto bad;
725 } else {
726 AHSTAT_INC(ahs_hist[sav->alg_auth]);
727 crypto_freereq(crp); /* No longer needed. */
728 crp = NULL;
729 }
730
731 /* Shouldn't happen... */
732 if (m == NULL) {
733 AHSTAT_INC(ahs_crypto);
734 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
735 error = EINVAL;
736 goto bad;
737 }
738
739 /* Figure out header size. */
740 rplen = HDRSIZE(sav);
741 authsize = AUTHSIZE(sav);
742 ahsize = ah_hdrsiz(sav);
743
744 /* Copy authenticator off the packet. */
745 m_copydata(m, skip + rplen, authsize, calc);
746
747 /* Verify authenticator. */
748 ptr = (caddr_t) (xd + 1);
749 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
750 DPRINTF(("%s: authentication hash mismatch for packet "
751 "in SA %s/%08lx\n", __func__,
752 ipsec_address(&saidx->dst, buf, sizeof(buf)),
753 (u_long) ntohl(sav->spi)));
754 AHSTAT_INC(ahs_badauth);
755 error = EACCES;
756 goto bad;
757 }
758 /* Fix the Next Protocol field. */
759 ((uint8_t *) ptr)[protoff] = nxt;
760
761 /* Copyback the saved (uncooked) network headers. */
762 m_copyback(m, 0, skip, ptr);
763 free(xd, M_XDATA), xd = NULL; /* No longer needed */
764
765 /*
766 * Header is now authenticated.
767 */
768 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
769
770 /*
771 * Update replay sequence number, if appropriate.
772 */
773 if (sav->replay) {
774 u_int32_t seq;
775
776 m_copydata(m, skip + offsetof(struct newah, ah_seq),
777 sizeof (seq), (caddr_t) &seq);
778 SECASVAR_LOCK(sav);
779 if (ipsec_updatereplay(ntohl(seq), sav)) {
780 SECASVAR_UNLOCK(sav);
781 AHSTAT_INC(ahs_replay);
782 error = EACCES;
783 goto bad;
784 }
785 SECASVAR_UNLOCK(sav);
786 }
787
788 /*
789 * Remove the AH header and authenticator from the mbuf.
790 */
791 error = m_striphdr(m, skip, ahsize);
792 if (error) {
793 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
794 ipsec_address(&saidx->dst, buf, sizeof(buf)),
795 (u_long) ntohl(sav->spi)));
796 AHSTAT_INC(ahs_hdrops);
797 goto bad;
798 }
799
800 switch (saidx->dst.sa.sa_family) {
801 #ifdef INET6
802 case AF_INET6:
803 error = ipsec6_common_input_cb(m, sav, skip, protoff);
804 break;
805 #endif
806 #ifdef INET
807 case AF_INET:
808 error = ipsec4_common_input_cb(m, sav, skip, protoff);
809 break;
810 #endif
811 default:
812 panic("%s: Unexpected address family: %d saidx=%p", __func__,
813 saidx->dst.sa.sa_family, saidx);
814 }
815 CURVNET_RESTORE();
816 return error;
817 bad:
818 CURVNET_RESTORE();
819 if (sav)
820 key_freesav(&sav);
821 if (m != NULL)
822 m_freem(m);
823 if (xd != NULL)
824 free(xd, M_XDATA);
825 if (crp != NULL)
826 crypto_freereq(crp);
827 return error;
828 }
829
830 /*
831 * AH output routine, called by ipsec[46]_perform_request().
832 */
833 static int
ah_output(struct mbuf * m,struct secpolicy * sp,struct secasvar * sav,u_int idx,int skip,int protoff)834 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
835 u_int idx, int skip, int protoff)
836 {
837 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
838 const struct auth_hash *ahx;
839 struct xform_data *xd;
840 struct mbuf *mi;
841 struct cryptop *crp;
842 struct newah *ah;
843 crypto_session_t cryptoid;
844 uint16_t iplen;
845 int error, rplen, authsize, ahsize, maxpacketsize, roff;
846 uint8_t prot;
847 uint32_t seqh;
848
849 IPSEC_ASSERT(sav != NULL, ("null SA"));
850 ahx = sav->tdb_authalgxform;
851 IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
852
853 AHSTAT_INC(ahs_output);
854
855 /* Figure out header size. */
856 rplen = HDRSIZE(sav);
857 authsize = AUTHSIZE(sav);
858 ahsize = ah_hdrsiz(sav);
859
860 /* Check for maximum packet size violations. */
861 switch (sav->sah->saidx.dst.sa.sa_family) {
862 #ifdef INET
863 case AF_INET:
864 maxpacketsize = IP_MAXPACKET;
865 break;
866 #endif /* INET */
867 #ifdef INET6
868 case AF_INET6:
869 maxpacketsize = IPV6_MAXPACKET;
870 break;
871 #endif /* INET6 */
872 default:
873 DPRINTF(("%s: unknown/unsupported protocol family %u, "
874 "SA %s/%08lx\n", __func__,
875 sav->sah->saidx.dst.sa.sa_family,
876 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
877 (u_long) ntohl(sav->spi)));
878 AHSTAT_INC(ahs_nopf);
879 error = EPFNOSUPPORT;
880 goto bad;
881 }
882 if (ahsize + m->m_pkthdr.len > maxpacketsize) {
883 DPRINTF(("%s: packet in SA %s/%08lx got too big "
884 "(len %u, max len %u)\n", __func__,
885 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
886 (u_long) ntohl(sav->spi),
887 ahsize + m->m_pkthdr.len, maxpacketsize));
888 AHSTAT_INC(ahs_toobig);
889 error = EMSGSIZE;
890 goto bad;
891 }
892
893 /* Update the counters. */
894 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
895
896 m = m_unshare(m, M_NOWAIT);
897 if (m == NULL) {
898 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
899 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
900 (u_long) ntohl(sav->spi)));
901 AHSTAT_INC(ahs_hdrops);
902 error = ENOBUFS;
903 goto bad;
904 }
905
906 /* Inject AH header. */
907 mi = m_makespace(m, skip, ahsize, &roff);
908 if (mi == NULL) {
909 DPRINTF(("%s: failed to inject %u byte AH header for SA "
910 "%s/%08lx\n", __func__, ahsize,
911 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
912 (u_long) ntohl(sav->spi)));
913 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
914 error = ENOBUFS;
915 goto bad;
916 }
917
918 /*
919 * The AH header is guaranteed by m_makespace() to be in
920 * contiguous memory, at roff bytes offset into the returned mbuf.
921 */
922 ah = (struct newah *)(mtod(mi, caddr_t) + roff);
923
924 /* Initialize the AH header. */
925 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
926 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t);
927 ah->ah_reserve = 0;
928 ah->ah_spi = sav->spi;
929
930 /* Zeroize authenticator. */
931 m_copyback(m, skip + rplen, authsize, ipseczeroes);
932
933 /* Zeroize padding */
934 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize),
935 ipseczeroes);
936
937 /* Insert packet replay counter, as requested. */
938 SECASVAR_LOCK(sav);
939 if (sav->replay) {
940 if ((sav->replay->count == ~0 ||
941 (!(sav->flags & SADB_X_SAFLAGS_ESN) &&
942 ((uint32_t)sav->replay->count) == ~0)) &&
943 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
944 SECASVAR_UNLOCK(sav);
945 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
946 __func__, ipsec_address(&sav->sah->saidx.dst, buf,
947 sizeof(buf)), (u_long) ntohl(sav->spi)));
948 AHSTAT_INC(ahs_wrap);
949 error = EACCES;
950 goto bad;
951 }
952 #ifdef REGRESSION
953 /* Emulate replay attack when ipsec_replay is TRUE. */
954 if (!V_ipsec_replay)
955 #endif
956 sav->replay->count++;
957 ah->ah_seq = htonl((uint32_t)sav->replay->count);
958 }
959 cryptoid = sav->tdb_cryptoid;
960 SECASVAR_UNLOCK(sav);
961
962 /* Get crypto descriptors. */
963 crp = crypto_getreq(cryptoid, M_NOWAIT);
964 if (crp == NULL) {
965 DPRINTF(("%s: failed to acquire crypto descriptors\n",
966 __func__));
967 AHSTAT_INC(ahs_crypto);
968 error = ENOBUFS;
969 goto bad;
970 }
971
972 crp->crp_payload_start = 0;
973 crp->crp_payload_length = m->m_pkthdr.len;
974 crp->crp_digest_start = skip + rplen;
975
976 /* Allocate IPsec-specific opaque crypto info. */
977 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA,
978 M_NOWAIT | M_ZERO);
979 if (xd == NULL) {
980 crypto_freereq(crp);
981 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
982 AHSTAT_INC(ahs_crypto);
983 error = ENOBUFS;
984 goto bad;
985 }
986
987 /* Save the skipped portion of the packet. */
988 m_copydata(m, 0, skip, (caddr_t) (xd + 1));
989
990 /*
991 * Fix IP header length on the header used for
992 * authentication. We don't need to fix the original
993 * header length as it will be fixed by our caller.
994 */
995 switch (sav->sah->saidx.dst.sa.sa_family) {
996 #ifdef INET
997 case AF_INET:
998 bcopy(((caddr_t)(xd + 1)) +
999 offsetof(struct ip, ip_len),
1000 (caddr_t) &iplen, sizeof(u_int16_t));
1001 iplen = htons(ntohs(iplen) + ahsize);
1002 m_copyback(m, offsetof(struct ip, ip_len),
1003 sizeof(u_int16_t), (caddr_t) &iplen);
1004 break;
1005 #endif /* INET */
1006
1007 #ifdef INET6
1008 case AF_INET6:
1009 bcopy(((caddr_t)(xd + 1)) +
1010 offsetof(struct ip6_hdr, ip6_plen),
1011 (caddr_t) &iplen, sizeof(uint16_t));
1012 iplen = htons(ntohs(iplen) + ahsize);
1013 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1014 sizeof(uint16_t), (caddr_t) &iplen);
1015 break;
1016 #endif /* INET6 */
1017 }
1018
1019 /* Fix the Next Header field in saved header. */
1020 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH;
1021
1022 /* Update the Next Protocol field in the IP header. */
1023 prot = IPPROTO_AH;
1024 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot);
1025
1026 /* "Massage" the packet headers for crypto processing. */
1027 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1028 skip, ahx->type, 1);
1029 if (error != 0) {
1030 m = NULL; /* mbuf was free'd by ah_massage_headers. */
1031 free(xd, M_XDATA);
1032 crypto_freereq(crp);
1033 goto bad;
1034 }
1035
1036 /* Crypto operation descriptor. */
1037 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST;
1038 crp->crp_flags = CRYPTO_F_CBIFSYNC;
1039 if (V_async_crypto)
1040 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
1041 crypto_use_mbuf(crp, m);
1042 crp->crp_callback = ah_output_cb;
1043 crp->crp_opaque = xd;
1044
1045 if (sav->flags & SADB_X_SAFLAGS_ESN && sav->replay != NULL) {
1046 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT));
1047 memcpy(crp->crp_esn, &seqh, sizeof(seqh));
1048 }
1049
1050 /* These are passed as-is to the callback. */
1051 xd->sp = sp;
1052 xd->sav = sav;
1053 xd->skip = skip;
1054 xd->idx = idx;
1055 xd->cryptoid = cryptoid;
1056 xd->vnet = curvnet;
1057
1058 return crypto_dispatch(crp);
1059 bad:
1060 if (m)
1061 m_freem(m);
1062 key_freesav(&sav);
1063 key_freesp(&sp);
1064 return (error);
1065 }
1066
1067 /*
1068 * AH output callback from the crypto driver.
1069 */
1070 static int
ah_output_cb(struct cryptop * crp)1071 ah_output_cb(struct cryptop *crp)
1072 {
1073 struct xform_data *xd;
1074 struct secpolicy *sp;
1075 struct secasvar *sav;
1076 struct mbuf *m;
1077 crypto_session_t cryptoid;
1078 caddr_t ptr;
1079 u_int idx;
1080 int skip, error;
1081
1082 m = crp->crp_buf.cb_mbuf;
1083 xd = (struct xform_data *) crp->crp_opaque;
1084 CURVNET_SET(xd->vnet);
1085 sp = xd->sp;
1086 sav = xd->sav;
1087 skip = xd->skip;
1088 idx = xd->idx;
1089 cryptoid = xd->cryptoid;
1090 ptr = (caddr_t) (xd + 1);
1091
1092 /* Check for crypto errors. */
1093 if (crp->crp_etype) {
1094 if (crp->crp_etype == EAGAIN) {
1095 /* Reset the session ID */
1096 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
1097 crypto_freesession(cryptoid);
1098 xd->cryptoid = crp->crp_session;
1099 CURVNET_RESTORE();
1100 return (crypto_dispatch(crp));
1101 }
1102 AHSTAT_INC(ahs_noxform);
1103 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
1104 error = crp->crp_etype;
1105 m_freem(m);
1106 goto bad;
1107 }
1108
1109 /* Shouldn't happen... */
1110 if (m == NULL) {
1111 AHSTAT_INC(ahs_crypto);
1112 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
1113 error = EINVAL;
1114 goto bad;
1115 }
1116 /*
1117 * Copy original headers (with the new protocol number) back
1118 * in place.
1119 */
1120 m_copyback(m, 0, skip, ptr);
1121
1122 free(xd, M_XDATA);
1123 crypto_freereq(crp);
1124 AHSTAT_INC(ahs_hist[sav->alg_auth]);
1125 #ifdef REGRESSION
1126 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1127 if (V_ipsec_integrity) {
1128 int alen;
1129
1130 /*
1131 * Corrupt HMAC if we want to test integrity verification of
1132 * the other side.
1133 */
1134 alen = AUTHSIZE(sav);
1135 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1136 }
1137 #endif
1138
1139 /* NB: m is reclaimed by ipsec_process_done. */
1140 error = ipsec_process_done(m, sp, sav, idx);
1141 CURVNET_RESTORE();
1142 return (error);
1143 bad:
1144 CURVNET_RESTORE();
1145 free(xd, M_XDATA);
1146 crypto_freereq(crp);
1147 key_freesav(&sav);
1148 key_freesp(&sp);
1149 return (error);
1150 }
1151
1152 static struct xformsw ah_xformsw = {
1153 .xf_type = XF_AH,
1154 .xf_name = "IPsec AH",
1155 .xf_init = ah_init,
1156 .xf_cleanup = ah_cleanup,
1157 .xf_input = ah_input,
1158 .xf_output = ah_output,
1159 };
1160
1161 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1162 xform_attach, &ah_xformsw);
1163 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1164 xform_detach, &ah_xformsw);
1165