1 /*-
2 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
3 * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD$
28 */
29
30 /*
31 * IPsec output processing.
32 */
33 #include "opt_inet.h"
34 #include "opt_inet6.h"
35 #include "opt_ipsec.h"
36 #include "opt_sctp.h"
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41 #include <sys/domain.h>
42 #include <sys/protosw.h>
43 #include <sys/socket.h>
44 #include <sys/errno.h>
45 #include <sys/hhook.h>
46 #include <sys/syslog.h>
47
48 #include <net/if.h>
49 #include <net/if_enc.h>
50 #include <net/if_var.h>
51 #include <net/vnet.h>
52
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/in_var.h>
58 #include <netinet/ip_ecn.h>
59 #ifdef INET6
60 #include <netinet6/ip6_ecn.h>
61 #endif
62
63 #include <netinet/ip6.h>
64 #ifdef INET6
65 #include <netinet6/ip6_var.h>
66 #include <netinet6/scope6_var.h>
67 #endif
68 #include <netinet/in_pcb.h>
69 #ifdef INET6
70 #include <netinet/icmp6.h>
71 #endif
72 #ifdef SCTP
73 #include <netinet/sctp_crc32.h>
74 #endif
75
76 #include <netinet/udp.h>
77 #include <netipsec/ah.h>
78 #include <netipsec/esp.h>
79 #include <netipsec/ipsec.h>
80 #ifdef INET6
81 #include <netipsec/ipsec6.h>
82 #endif
83 #include <netipsec/ah_var.h>
84 #include <netipsec/esp_var.h>
85 #include <netipsec/ipcomp_var.h>
86
87 #include <netipsec/xform.h>
88
89 #include <netipsec/key.h>
90 #include <netipsec/keydb.h>
91 #include <netipsec/key_debug.h>
92
93 #include <machine/in_cksum.h>
94
95 #define IPSEC_OSTAT_INC(proto, name) do { \
96 if ((proto) == IPPROTO_ESP) \
97 ESPSTAT_INC(esps_##name); \
98 else if ((proto) == IPPROTO_AH)\
99 AHSTAT_INC(ahs_##name); \
100 else \
101 IPCOMPSTAT_INC(ipcomps_##name); \
102 } while (0)
103
104 static int ipsec_encap(struct mbuf **mp, struct secasindex *saidx);
105
106 #ifdef INET
107 static struct secasvar *
108 ipsec4_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error)
109 {
110 struct secasindex *saidx, tmpsaidx;
111 struct ipsecrequest *isr;
112 struct sockaddr_in *sin;
113 struct secasvar *sav;
114 struct ip *ip;
115
116 /*
117 * Check system global policy controls.
118 */
119 next:
120 isr = sp->req[*pidx];
121 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
122 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
123 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
124 DPRINTF(("%s: IPsec outbound packet dropped due"
125 " to policy (check your sysctls)\n", __func__));
126 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops);
127 *error = EHOSTUNREACH;
128 return (NULL);
129 }
130 /*
131 * Craft SA index to search for proper SA. Note that
132 * we only initialize unspecified SA peers for transport
133 * mode; for tunnel mode they must already be filled in.
134 */
135 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
136 saidx = &tmpsaidx;
137 *saidx = isr->saidx;
138 ip = mtod(m, struct ip *);
139 if (saidx->src.sa.sa_len == 0) {
140 sin = &saidx->src.sin;
141 sin->sin_len = sizeof(*sin);
142 sin->sin_family = AF_INET;
143 sin->sin_port = IPSEC_PORT_ANY;
144 sin->sin_addr = ip->ip_src;
145 }
146 if (saidx->dst.sa.sa_len == 0) {
147 sin = &saidx->dst.sin;
148 sin->sin_len = sizeof(*sin);
149 sin->sin_family = AF_INET;
150 sin->sin_port = IPSEC_PORT_ANY;
151 sin->sin_addr = ip->ip_dst;
152 }
153 } else
154 saidx = &sp->req[*pidx]->saidx;
155 /*
156 * Lookup SA and validate it.
157 */
158 sav = key_allocsa_policy(sp, saidx, error);
159 if (sav == NULL) {
160 IPSECSTAT_INC(ips_out_nosa);
161 if (*error != 0)
162 return (NULL);
163 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) {
164 /*
165 * We have no SA and policy that doesn't require
166 * this IPsec transform, thus we can continue w/o
167 * IPsec processing, i.e. return EJUSTRETURN.
168 * But first check if there is some bundled transform.
169 */
170 if (sp->tcount > ++(*pidx))
171 goto next;
172 *error = EJUSTRETURN;
173 }
174 return (NULL);
175 }
176 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform"));
177 return (sav);
178 }
179
180 /*
181 * IPsec output logic for IPv4.
182 */
183 static int
184 ipsec4_perform_request(struct mbuf *m, struct secpolicy *sp,
185 struct inpcb *inp, u_int idx)
186 {
187 struct ipsec_ctx_data ctx;
188 union sockaddr_union *dst;
189 struct secasvar *sav;
190 struct ip *ip;
191 int error, i, off;
192
193 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx));
194
195 /*
196 * We hold the reference to SP. Content of SP couldn't be changed.
197 * Craft secasindex and do lookup for suitable SA.
198 * Then do encapsulation if needed and call xform's output.
199 * We need to store SP in the xform callback parameters.
200 * In xform callback we will extract SP and it can be used to
201 * determine next transform. At the end of transform we can
202 * release reference to SP.
203 */
204 sav = ipsec4_allocsa(m, sp, &idx, &error);
205 if (sav == NULL) {
206 if (error == EJUSTRETURN) { /* No IPsec required */
207 key_freesp(&sp);
208 return (error);
209 }
210 goto bad;
211 }
212 /*
213 * XXXAE: most likely ip_sum at this point is wrong.
214 */
215 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET, IPSEC_ENC_BEFORE);
216 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
217 goto bad;
218
219 ip = mtod(m, struct ip *);
220 dst = &sav->sah->saidx.dst;
221 /* Do the appropriate encapsulation, if necessary */
222 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
223 dst->sa.sa_family != AF_INET || /* PF mismatch */
224 (dst->sa.sa_family == AF_INET && /* Proxy */
225 dst->sin.sin_addr.s_addr != INADDR_ANY &&
226 dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
227 /* Fix IPv4 header checksum and length */
228 ip->ip_len = htons(m->m_pkthdr.len);
229 ip->ip_sum = 0;
230 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
231 error = ipsec_encap(&m, &sav->sah->saidx);
232 if (error != 0) {
233 DPRINTF(("%s: encapsulation for SPI 0x%08x failed "
234 "with error %d\n", __func__, ntohl(sav->spi),
235 error));
236 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */
237 goto bad;
238 }
239 inp = NULL;
240 }
241
242 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER);
243 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
244 goto bad;
245
246 /*
247 * Dispatch to the appropriate IPsec transform logic. The
248 * packet will be returned for transmission after crypto
249 * processing, etc. are completed.
250 *
251 * NB: m & sav are ``passed to caller'' who's responsible for
252 * reclaiming their resources.
253 */
254 switch(dst->sa.sa_family) {
255 case AF_INET:
256 ip = mtod(m, struct ip *);
257 i = ip->ip_hl << 2;
258 off = offsetof(struct ip, ip_p);
259 break;
260 #ifdef INET6
261 case AF_INET6:
262 i = sizeof(struct ip6_hdr);
263 off = offsetof(struct ip6_hdr, ip6_nxt);
264 break;
265 #endif /* INET6 */
266 default:
267 DPRINTF(("%s: unsupported protocol family %u\n",
268 __func__, dst->sa.sa_family));
269 error = EPFNOSUPPORT;
270 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf);
271 goto bad;
272 }
273 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off);
274 return (error);
275 bad:
276 IPSECSTAT_INC(ips_out_inval);
277 if (m != NULL)
278 m_freem(m);
279 if (sav != NULL)
280 key_freesav(&sav);
281 key_freesp(&sp);
282 return (error);
283 }
284
285 int
286 ipsec4_process_packet(struct mbuf *m, struct secpolicy *sp,
287 struct inpcb *inp)
288 {
289
290 return (ipsec4_perform_request(m, sp, inp, 0));
291 }
292
293 static int
294 ipsec4_common_output(struct mbuf *m, struct inpcb *inp, int forwarding)
295 {
296 struct secpolicy *sp;
297 int error;
298
299 /* Lookup for the corresponding outbound security policy */
300 sp = ipsec4_checkpolicy(m, inp, &error, !forwarding);
301 if (sp == NULL) {
302 if (error == -EINVAL) {
303 /* Discarded by policy. */
304 m_freem(m);
305 return (EACCES);
306 }
307 return (0); /* No IPsec required. */
308 }
309
310 /*
311 * Usually we have to have tunnel mode IPsec security policy
312 * when we are forwarding a packet. Otherwise we could not handle
313 * encrypted replies, because they are not destined for us. But
314 * some users are doing source address translation for forwarded
315 * packets, and thus, even if they are forwarded, the replies will
316 * return back to us.
317 */
318 if (!forwarding) {
319 /*
320 * Do delayed checksums now because we send before
321 * this is done in the normal processing path.
322 */
323 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
324 in_delayed_cksum(m);
325 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
326 }
327 #ifdef SCTP
328 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
329 struct ip *ip = mtod(m, struct ip *);
330
331 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
332 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
333 }
334 #endif
335 }
336 /* NB: callee frees mbuf and releases reference to SP */
337 error = ipsec4_process_packet(m, sp, inp);
338 if (error == EJUSTRETURN) {
339 /*
340 * We had a SP with a level of 'use' and no SA. We
341 * will just continue to process the packet without
342 * IPsec processing and return without error.
343 */
344 return (0);
345 }
346 if (error == 0)
347 return (EINPROGRESS); /* consumed by IPsec */
348 return (error);
349 }
350
351 /*
352 * IPSEC_OUTPUT() method implementation for IPv4.
353 * 0 - no IPsec handling needed
354 * other values - mbuf consumed by IPsec.
355 */
356 int
357 ipsec4_output(struct mbuf *m, struct inpcb *inp)
358 {
359
360 /*
361 * If the packet is resubmitted to ip_output (e.g. after
362 * AH, ESP, etc. processing), there will be a tag to bypass
363 * the lookup and related policy checking.
364 */
365 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
366 return (0);
367
368 return (ipsec4_common_output(m, inp, 0));
369 }
370
371 /*
372 * IPSEC_FORWARD() method implementation for IPv4.
373 * 0 - no IPsec handling needed
374 * other values - mbuf consumed by IPsec.
375 */
376 int
377 ipsec4_forward(struct mbuf *m)
378 {
379
380 /*
381 * Check if this packet has an active inbound SP and needs to be
382 * dropped instead of forwarded.
383 */
384 if (ipsec4_in_reject(m, NULL) != 0) {
385 m_freem(m);
386 return (EACCES);
387 }
388 return (ipsec4_common_output(m, NULL, 1));
389 }
390 #endif
391
392 #ifdef INET6
393 static int
394 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa,
395 const struct in6_addr *ia)
396 {
397 struct in6_addr ia2;
398
399 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) {
400 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
401 ia2.s6_addr16[1] = htons(sa->sin6_scope_id);
402 return (IN6_ARE_ADDR_EQUAL(ia, &ia2));
403 }
404 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia));
405 }
406
407 static struct secasvar *
408 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error)
409 {
410 struct secasindex *saidx, tmpsaidx;
411 struct ipsecrequest *isr;
412 struct sockaddr_in6 *sin6;
413 struct secasvar *sav;
414 struct ip6_hdr *ip6;
415
416 /*
417 * Check system global policy controls.
418 */
419 next:
420 isr = sp->req[*pidx];
421 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
422 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
423 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
424 DPRINTF(("%s: IPsec outbound packet dropped due"
425 " to policy (check your sysctls)\n", __func__));
426 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops);
427 *error = EHOSTUNREACH;
428 return (NULL);
429 }
430 /*
431 * Craft SA index to search for proper SA. Note that
432 * we only fillin unspecified SA peers for transport
433 * mode; for tunnel mode they must already be filled in.
434 */
435 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
436 saidx = &tmpsaidx;
437 *saidx = isr->saidx;
438 ip6 = mtod(m, struct ip6_hdr *);
439 if (saidx->src.sin6.sin6_len == 0) {
440 sin6 = (struct sockaddr_in6 *)&saidx->src;
441 sin6->sin6_len = sizeof(*sin6);
442 sin6->sin6_family = AF_INET6;
443 sin6->sin6_port = IPSEC_PORT_ANY;
444 sin6->sin6_addr = ip6->ip6_src;
445 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
446 /* fix scope id for comparing SPD */
447 sin6->sin6_addr.s6_addr16[1] = 0;
448 sin6->sin6_scope_id =
449 ntohs(ip6->ip6_src.s6_addr16[1]);
450 }
451 }
452 if (saidx->dst.sin6.sin6_len == 0) {
453 sin6 = (struct sockaddr_in6 *)&saidx->dst;
454 sin6->sin6_len = sizeof(*sin6);
455 sin6->sin6_family = AF_INET6;
456 sin6->sin6_port = IPSEC_PORT_ANY;
457 sin6->sin6_addr = ip6->ip6_dst;
458 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
459 /* fix scope id for comparing SPD */
460 sin6->sin6_addr.s6_addr16[1] = 0;
461 sin6->sin6_scope_id =
462 ntohs(ip6->ip6_dst.s6_addr16[1]);
463 }
464 }
465 } else
466 saidx = &sp->req[*pidx]->saidx;
467 /*
468 * Lookup SA and validate it.
469 */
470 sav = key_allocsa_policy(sp, saidx, error);
471 if (sav == NULL) {
472 IPSEC6STAT_INC(ips_out_nosa);
473 if (*error != 0)
474 return (NULL);
475 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) {
476 /*
477 * We have no SA and policy that doesn't require
478 * this IPsec transform, thus we can continue w/o
479 * IPsec processing, i.e. return EJUSTRETURN.
480 * But first check if there is some bundled transform.
481 */
482 if (sp->tcount > ++(*pidx))
483 goto next;
484 *error = EJUSTRETURN;
485 }
486 return (NULL);
487 }
488 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform"));
489 return (sav);
490 }
491
492 /*
493 * IPsec output logic for IPv6.
494 */
495 static int
496 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp,
497 struct inpcb *inp, u_int idx)
498 {
499 struct ipsec_ctx_data ctx;
500 union sockaddr_union *dst;
501 struct secasvar *sav;
502 struct ip6_hdr *ip6;
503 int error, i, off;
504
505 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx));
506
507 sav = ipsec6_allocsa(m, sp, &idx, &error);
508 if (sav == NULL) {
509 if (error == EJUSTRETURN) { /* No IPsec required */
510 key_freesp(&sp);
511 return (error);
512 }
513 goto bad;
514 }
515
516 /* Fix IP length in case if it is not set yet. */
517 ip6 = mtod(m, struct ip6_hdr *);
518 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
519
520 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE);
521 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
522 goto bad;
523
524 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */
525 dst = &sav->sah->saidx.dst;
526
527 /* Do the appropriate encapsulation, if necessary */
528 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
529 dst->sa.sa_family != AF_INET6 || /* PF mismatch */
530 ((dst->sa.sa_family == AF_INET6) &&
531 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
532 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) {
533 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
534 /* No jumbogram support. */
535 error = ENXIO; /*XXX*/
536 goto bad;
537 }
538 error = ipsec_encap(&m, &sav->sah->saidx);
539 if (error != 0) {
540 DPRINTF(("%s: encapsulation for SPI 0x%08x failed "
541 "with error %d\n", __func__, ntohl(sav->spi),
542 error));
543 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */
544 goto bad;
545 }
546 inp = NULL;
547 }
548
549 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER);
550 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
551 goto bad;
552
553 switch(dst->sa.sa_family) {
554 #ifdef INET
555 case AF_INET:
556 {
557 struct ip *ip;
558 ip = mtod(m, struct ip *);
559 i = ip->ip_hl << 2;
560 off = offsetof(struct ip, ip_p);
561 }
562 break;
563 #endif /* AF_INET */
564 case AF_INET6:
565 i = sizeof(struct ip6_hdr);
566 off = offsetof(struct ip6_hdr, ip6_nxt);
567 break;
568 default:
569 DPRINTF(("%s: unsupported protocol family %u\n",
570 __func__, dst->sa.sa_family));
571 error = EPFNOSUPPORT;
572 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf);
573 goto bad;
574 }
575 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off);
576 return (error);
577 bad:
578 IPSEC6STAT_INC(ips_out_inval);
579 if (m != NULL)
580 m_freem(m);
581 if (sav != NULL)
582 key_freesav(&sav);
583 key_freesp(&sp);
584 return (error);
585 }
586
587 int
588 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp,
589 struct inpcb *inp)
590 {
591
592 return (ipsec6_perform_request(m, sp, inp, 0));
593 }
594
595 static int
596 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding)
597 {
598 struct secpolicy *sp;
599 int error;
600
601 /* Lookup for the corresponding outbound security policy */
602 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding);
603 if (sp == NULL) {
604 if (error == -EINVAL) {
605 /* Discarded by policy. */
606 m_freem(m);
607 return (EACCES);
608 }
609 return (0); /* No IPsec required. */
610 }
611
612 if (!forwarding) {
613 /*
614 * Do delayed checksums now because we send before
615 * this is done in the normal processing path.
616 */
617 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
618 in6_delayed_cksum(m, m->m_pkthdr.len -
619 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr));
620 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
621 }
622 #ifdef SCTP
623 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
624 sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
625 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
626 }
627 #endif
628 }
629 /* NB: callee frees mbuf and releases reference to SP */
630 error = ipsec6_process_packet(m, sp, inp);
631 if (error == EJUSTRETURN) {
632 /*
633 * We had a SP with a level of 'use' and no SA. We
634 * will just continue to process the packet without
635 * IPsec processing and return without error.
636 */
637 return (0);
638 }
639 if (error == 0)
640 return (EINPROGRESS); /* consumed by IPsec */
641 return (error);
642 }
643
644 /*
645 * IPSEC_OUTPUT() method implementation for IPv6.
646 * 0 - no IPsec handling needed
647 * other values - mbuf consumed by IPsec.
648 */
649 int
650 ipsec6_output(struct mbuf *m, struct inpcb *inp)
651 {
652
653 /*
654 * If the packet is resubmitted to ip_output (e.g. after
655 * AH, ESP, etc. processing), there will be a tag to bypass
656 * the lookup and related policy checking.
657 */
658 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
659 return (0);
660
661 return (ipsec6_common_output(m, inp, 0));
662 }
663
664 /*
665 * IPSEC_FORWARD() method implementation for IPv6.
666 * 0 - no IPsec handling needed
667 * other values - mbuf consumed by IPsec.
668 */
669 int
670 ipsec6_forward(struct mbuf *m)
671 {
672
673 /*
674 * Check if this packet has an active inbound SP and needs to be
675 * dropped instead of forwarded.
676 */
677 if (ipsec6_in_reject(m, NULL) != 0) {
678 m_freem(m);
679 return (EACCES);
680 }
681 return (ipsec6_common_output(m, NULL, 1));
682 }
683 #endif /* INET6 */
684
685 int
686 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
687 u_int idx)
688 {
689 struct xform_history *xh;
690 struct secasindex *saidx;
691 struct m_tag *mtag;
692 int error;
693
694 saidx = &sav->sah->saidx;
695 switch (saidx->dst.sa.sa_family) {
696 #ifdef INET
697 case AF_INET:
698 /* Fix the header length, for AH processing. */
699 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
700 break;
701 #endif /* INET */
702 #ifdef INET6
703 case AF_INET6:
704 /* Fix the header length, for AH processing. */
705 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
706 error = ENXIO;
707 goto bad;
708 }
709 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
710 /* No jumbogram support. */
711 error = ENXIO; /*?*/
712 goto bad;
713 }
714 mtod(m, struct ip6_hdr *)->ip6_plen =
715 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
716 break;
717 #endif /* INET6 */
718 default:
719 DPRINTF(("%s: unknown protocol family %u\n", __func__,
720 saidx->dst.sa.sa_family));
721 error = ENXIO;
722 goto bad;
723 }
724
725 /*
726 * Add a record of what we've done to the packet.
727 */
728 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT);
729 if (mtag == NULL) {
730 DPRINTF(("%s: could not get packet tag\n", __func__));
731 error = ENOMEM;
732 goto bad;
733 }
734
735 xh = (struct xform_history *)(mtag + 1);
736 xh->dst = saidx->dst;
737 xh->proto = saidx->proto;
738 xh->mode = saidx->mode;
739 xh->spi = sav->spi;
740 m_tag_prepend(m, mtag);
741
742 key_sa_recordxfer(sav, m); /* record data transfer */
743
744 /*
745 * If there's another (bundled) SA to apply, do so.
746 * Note that this puts a burden on the kernel stack size.
747 * If this is a problem we'll need to introduce a queue
748 * to set the packet on so we can unwind the stack before
749 * doing further processing.
750 */
751 if (++idx < sp->tcount) {
752 switch (saidx->dst.sa.sa_family) {
753 #ifdef INET
754 case AF_INET:
755 key_freesav(&sav);
756 IPSECSTAT_INC(ips_out_bundlesa);
757 return (ipsec4_perform_request(m, sp, NULL, idx));
758 /* NOTREACHED */
759 #endif
760 #ifdef INET6
761 case AF_INET6:
762 key_freesav(&sav);
763 IPSEC6STAT_INC(ips_out_bundlesa);
764 return (ipsec6_perform_request(m, sp, NULL, idx));
765 /* NOTREACHED */
766 #endif /* INET6 */
767 default:
768 DPRINTF(("%s: unknown protocol family %u\n", __func__,
769 saidx->dst.sa.sa_family));
770 error = EPFNOSUPPORT;
771 goto bad;
772 }
773 }
774
775 key_freesp(&sp), sp = NULL; /* Release reference to SP */
776 #ifdef INET
777 /*
778 * Do UDP encapsulation if SA requires it.
779 */
780 if (sav->natt != NULL) {
781 error = udp_ipsec_output(m, sav);
782 if (error != 0)
783 goto bad;
784 }
785 #endif /* INET */
786 /*
787 * We're done with IPsec processing, transmit the packet using the
788 * appropriate network protocol (IP or IPv6).
789 */
790 switch (saidx->dst.sa.sa_family) {
791 #ifdef INET
792 case AF_INET:
793 key_freesav(&sav);
794 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
795 #endif /* INET */
796 #ifdef INET6
797 case AF_INET6:
798 key_freesav(&sav);
799 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
800 #endif /* INET6 */
801 }
802 panic("ipsec_process_done");
803 bad:
804 m_freem(m);
805 key_freesav(&sav);
806 if (sp != NULL)
807 key_freesp(&sp);
808 return (error);
809 }
810
811 /*
812 * ipsec_prepend() is optimized version of M_PREPEND().
813 * ipsec_encap() is called by IPsec output routine for tunnel mode SA.
814 * It is expected that after IP encapsulation some IPsec transform will
815 * be performed. Each IPsec transform inserts its variable length header
816 * just after outer IP header using m_makespace(). If given mbuf has not
817 * enough free space at the beginning, we allocate new mbuf and reserve
818 * some space at the beginning and at the end.
819 * This helps avoid allocating of new mbuf and data copying in m_makespace(),
820 * we place outer header in the middle of mbuf's data with reserved leading
821 * and trailing space:
822 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ]
823 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will
824 * be used to inject AH/ESP/IPCOMP header.
825 */
826 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \
827 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \
828 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */))
829 static struct mbuf *
830 ipsec_prepend(struct mbuf *m, int len, int how)
831 {
832 struct mbuf *n;
833
834 M_ASSERTPKTHDR(m);
835 IPSEC_ASSERT(len < MHLEN, ("wrong length"));
836 if (M_LEADINGSPACE(m) >= len) {
837 /* No need to allocate new mbuf. */
838 m->m_data -= len;
839 m->m_len += len;
840 m->m_pkthdr.len += len;
841 return (m);
842 }
843 n = m_gethdr(how, m->m_type);
844 if (n == NULL) {
845 m_freem(m);
846 return (NULL);
847 }
848 m_move_pkthdr(n, m);
849 n->m_next = m;
850 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n))
851 m_align(n, len + IPSEC_TRAILINGSPACE);
852 n->m_len = len;
853 n->m_pkthdr.len += len;
854 return (n);
855 }
856
857 static int
858 ipsec_encap(struct mbuf **mp, struct secasindex *saidx)
859 {
860 #ifdef INET6
861 struct ip6_hdr *ip6;
862 #endif
863 struct ip *ip;
864 int setdf;
865 uint8_t itos, proto;
866
867 ip = mtod(*mp, struct ip *);
868 switch (ip->ip_v) {
869 #ifdef INET
870 case IPVERSION:
871 proto = IPPROTO_IPIP;
872 /*
873 * Collect IP_DF state from the inner header
874 * and honor system-wide control of how to handle it.
875 */
876 switch (V_ip4_ipsec_dfbit) {
877 case 0: /* clear in outer header */
878 case 1: /* set in outer header */
879 setdf = V_ip4_ipsec_dfbit;
880 break;
881 default:/* propagate to outer header */
882 setdf = (ip->ip_off & htons(IP_DF)) != 0;
883 }
884 itos = ip->ip_tos;
885 break;
886 #endif
887 #ifdef INET6
888 case (IPV6_VERSION >> 4):
889 proto = IPPROTO_IPV6;
890 ip6 = mtod(*mp, struct ip6_hdr *);
891 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
892 setdf = V_ip4_ipsec_dfbit ? 1: 0;
893 /* scoped address handling */
894 in6_clearscope(&ip6->ip6_src);
895 in6_clearscope(&ip6->ip6_dst);
896 break;
897 #endif
898 default:
899 return (EAFNOSUPPORT);
900 }
901 switch (saidx->dst.sa.sa_family) {
902 #ifdef INET
903 case AF_INET:
904 if (saidx->src.sa.sa_family != AF_INET ||
905 saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
906 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY)
907 return (EINVAL);
908 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT);
909 if (*mp == NULL)
910 return (ENOBUFS);
911 ip = mtod(*mp, struct ip *);
912 ip->ip_v = IPVERSION;
913 ip->ip_hl = sizeof(struct ip) >> 2;
914 ip->ip_p = proto;
915 ip->ip_len = htons((*mp)->m_pkthdr.len);
916 ip->ip_ttl = V_ip_defttl;
917 ip->ip_sum = 0;
918 ip->ip_off = setdf ? htons(IP_DF): 0;
919 ip->ip_src = saidx->src.sin.sin_addr;
920 ip->ip_dst = saidx->dst.sin.sin_addr;
921 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos);
922 ip_fillid(ip);
923 break;
924 #endif /* INET */
925 #ifdef INET6
926 case AF_INET6:
927 if (saidx->src.sa.sa_family != AF_INET6 ||
928 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) ||
929 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr))
930 return (EINVAL);
931 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT);
932 if (*mp == NULL)
933 return (ENOBUFS);
934 ip6 = mtod(*mp, struct ip6_hdr *);
935 ip6->ip6_flow = 0;
936 ip6->ip6_vfc = IPV6_VERSION;
937 ip6->ip6_hlim = V_ip6_defhlim;
938 ip6->ip6_nxt = proto;
939 ip6->ip6_dst = saidx->dst.sin6.sin6_addr;
940 /* For link-local address embed scope zone id */
941 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
942 ip6->ip6_dst.s6_addr16[1] =
943 htons(saidx->dst.sin6.sin6_scope_id & 0xffff);
944 ip6->ip6_src = saidx->src.sin6.sin6_addr;
945 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
946 ip6->ip6_src.s6_addr16[1] =
947 htons(saidx->src.sin6.sin6_scope_id & 0xffff);
948 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6));
949 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos);
950 ip6->ip6_flow |= htonl((uint32_t)proto << 20);
951 break;
952 #endif /* INET6 */
953 default:
954 return (EAFNOSUPPORT);
955 }
956 (*mp)->m_flags &= ~(M_BCAST | M_MCAST);
957 return (0);
958 }
959
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