1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
5 * Copyright (c) 2016 Andrey V. Elsukov <[email protected]>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32 /*
33 * IPsec output processing.
34 */
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 #include "opt_ipsec.h"
38 #include "opt_sctp.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/mbuf.h>
43 #include <sys/domain.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/errno.h>
47 #include <sys/hhook.h>
48 #include <sys/syslog.h>
49
50 #include <net/if.h>
51 #include <net/if_enc.h>
52 #include <net/if_var.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_var.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip_ecn.h>
61 #ifdef INET6
62 #include <netinet6/ip6_ecn.h>
63 #endif
64
65 #include <netinet/ip6.h>
66 #ifdef INET6
67 #include <netinet6/ip6_var.h>
68 #include <netinet6/scope6_var.h>
69 #endif
70 #include <netinet/in_pcb.h>
71 #ifdef INET6
72 #include <netinet/icmp6.h>
73 #endif
74 #if defined(SCTP) || defined(SCTP_SUPPORT)
75 #include <netinet/sctp_crc32.h>
76 #endif
77
78 #include <netinet/udp.h>
79 #include <netipsec/ah.h>
80 #include <netipsec/esp.h>
81 #include <netipsec/ipsec.h>
82 #ifdef INET6
83 #include <netipsec/ipsec6.h>
84 #endif
85 #include <netipsec/ah_var.h>
86 #include <netipsec/esp_var.h>
87 #include <netipsec/ipcomp_var.h>
88
89 #include <netipsec/xform.h>
90
91 #include <netipsec/key.h>
92 #include <netipsec/keydb.h>
93 #include <netipsec/key_debug.h>
94
95 #include <machine/in_cksum.h>
96
97 #define IPSEC_OSTAT_INC(proto, name) do { \
98 if ((proto) == IPPROTO_ESP) \
99 ESPSTAT_INC(esps_##name); \
100 else if ((proto) == IPPROTO_AH)\
101 AHSTAT_INC(ahs_##name); \
102 else \
103 IPCOMPSTAT_INC(ipcomps_##name); \
104 } while (0)
105
106 static int ipsec_encap(struct mbuf **mp, struct secasindex *saidx);
107
108 #ifdef INET
109 static struct secasvar *
ipsec4_allocsa(struct mbuf * m,struct secpolicy * sp,u_int * pidx,int * error)110 ipsec4_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error)
111 {
112 struct secasindex *saidx, tmpsaidx;
113 struct ipsecrequest *isr;
114 struct sockaddr_in *sin;
115 struct secasvar *sav;
116 struct ip *ip;
117
118 /*
119 * Check system global policy controls.
120 */
121 next:
122 isr = sp->req[*pidx];
123 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
124 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
125 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
126 DPRINTF(("%s: IPsec outbound packet dropped due"
127 " to policy (check your sysctls)\n", __func__));
128 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops);
129 *error = EHOSTUNREACH;
130 return (NULL);
131 }
132 /*
133 * Craft SA index to search for proper SA. Note that
134 * we only initialize unspecified SA peers for transport
135 * mode; for tunnel mode they must already be filled in.
136 */
137 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
138 saidx = &tmpsaidx;
139 *saidx = isr->saidx;
140 ip = mtod(m, struct ip *);
141 if (saidx->src.sa.sa_len == 0) {
142 sin = &saidx->src.sin;
143 sin->sin_len = sizeof(*sin);
144 sin->sin_family = AF_INET;
145 sin->sin_port = IPSEC_PORT_ANY;
146 sin->sin_addr = ip->ip_src;
147 }
148 if (saidx->dst.sa.sa_len == 0) {
149 sin = &saidx->dst.sin;
150 sin->sin_len = sizeof(*sin);
151 sin->sin_family = AF_INET;
152 sin->sin_port = IPSEC_PORT_ANY;
153 sin->sin_addr = ip->ip_dst;
154 }
155 } else
156 saidx = &sp->req[*pidx]->saidx;
157 /*
158 * Lookup SA and validate it.
159 */
160 sav = key_allocsa_policy(sp, saidx, error);
161 if (sav == NULL) {
162 IPSECSTAT_INC(ips_out_nosa);
163 if (*error != 0)
164 return (NULL);
165 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) {
166 /*
167 * We have no SA and policy that doesn't require
168 * this IPsec transform, thus we can continue w/o
169 * IPsec processing, i.e. return EJUSTRETURN.
170 * But first check if there is some bundled transform.
171 */
172 if (sp->tcount > ++(*pidx))
173 goto next;
174 *error = EJUSTRETURN;
175 }
176 return (NULL);
177 }
178 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform"));
179 return (sav);
180 }
181
182 /*
183 * IPsec output logic for IPv4.
184 */
185 static int
ipsec4_perform_request(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp,u_int idx)186 ipsec4_perform_request(struct mbuf *m, struct secpolicy *sp,
187 struct inpcb *inp, u_int idx)
188 {
189 struct ipsec_ctx_data ctx;
190 union sockaddr_union *dst;
191 struct secasvar *sav;
192 struct ip *ip;
193 int error, i, off;
194
195 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx));
196
197 /*
198 * We hold the reference to SP. Content of SP couldn't be changed.
199 * Craft secasindex and do lookup for suitable SA.
200 * Then do encapsulation if needed and call xform's output.
201 * We need to store SP in the xform callback parameters.
202 * In xform callback we will extract SP and it can be used to
203 * determine next transform. At the end of transform we can
204 * release reference to SP.
205 */
206 sav = ipsec4_allocsa(m, sp, &idx, &error);
207 if (sav == NULL) {
208 if (error == EJUSTRETURN) { /* No IPsec required */
209 key_freesp(&sp);
210 return (error);
211 }
212 goto bad;
213 }
214 /*
215 * XXXAE: most likely ip_sum at this point is wrong.
216 */
217 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET, IPSEC_ENC_BEFORE);
218 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
219 goto bad;
220
221 ip = mtod(m, struct ip *);
222 dst = &sav->sah->saidx.dst;
223 /* Do the appropriate encapsulation, if necessary */
224 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
225 dst->sa.sa_family != AF_INET || /* PF mismatch */
226 (dst->sa.sa_family == AF_INET && /* Proxy */
227 dst->sin.sin_addr.s_addr != INADDR_ANY &&
228 dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
229 /* Fix IPv4 header checksum and length */
230 ip->ip_len = htons(m->m_pkthdr.len);
231 ip->ip_sum = 0;
232 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
233 error = ipsec_encap(&m, &sav->sah->saidx);
234 if (error != 0) {
235 DPRINTF(("%s: encapsulation for SPI 0x%08x failed "
236 "with error %d\n", __func__, ntohl(sav->spi),
237 error));
238 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */
239 goto bad;
240 }
241 inp = NULL;
242 }
243
244 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER);
245 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
246 goto bad;
247
248 /*
249 * Dispatch to the appropriate IPsec transform logic. The
250 * packet will be returned for transmission after crypto
251 * processing, etc. are completed.
252 *
253 * NB: m & sav are ``passed to caller'' who's responsible for
254 * reclaiming their resources.
255 */
256 switch(dst->sa.sa_family) {
257 case AF_INET:
258 ip = mtod(m, struct ip *);
259 i = ip->ip_hl << 2;
260 off = offsetof(struct ip, ip_p);
261 break;
262 #ifdef INET6
263 case AF_INET6:
264 i = sizeof(struct ip6_hdr);
265 off = offsetof(struct ip6_hdr, ip6_nxt);
266 break;
267 #endif /* INET6 */
268 default:
269 DPRINTF(("%s: unsupported protocol family %u\n",
270 __func__, dst->sa.sa_family));
271 error = EPFNOSUPPORT;
272 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf);
273 goto bad;
274 }
275 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off);
276 return (error);
277 bad:
278 IPSECSTAT_INC(ips_out_inval);
279 if (m != NULL)
280 m_freem(m);
281 if (sav != NULL)
282 key_freesav(&sav);
283 key_freesp(&sp);
284 return (error);
285 }
286
287 int
ipsec4_process_packet(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp)288 ipsec4_process_packet(struct mbuf *m, struct secpolicy *sp,
289 struct inpcb *inp)
290 {
291
292 return (ipsec4_perform_request(m, sp, inp, 0));
293 }
294
295 static int
ipsec4_common_output(struct mbuf * m,struct inpcb * inp,int forwarding)296 ipsec4_common_output(struct mbuf *m, struct inpcb *inp, int forwarding)
297 {
298 struct secpolicy *sp;
299 int error;
300
301 /* Lookup for the corresponding outbound security policy */
302 sp = ipsec4_checkpolicy(m, inp, &error, !forwarding);
303 if (sp == NULL) {
304 if (error == -EINVAL) {
305 /* Discarded by policy. */
306 m_freem(m);
307 return (EACCES);
308 }
309 return (0); /* No IPsec required. */
310 }
311
312 /*
313 * Usually we have to have tunnel mode IPsec security policy
314 * when we are forwarding a packet. Otherwise we could not handle
315 * encrypted replies, because they are not destined for us. But
316 * some users are doing source address translation for forwarded
317 * packets, and thus, even if they are forwarded, the replies will
318 * return back to us.
319 */
320 if (!forwarding) {
321 /*
322 * Do delayed checksums now because we send before
323 * this is done in the normal processing path.
324 */
325 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
326 m = mb_unmapped_to_ext(m);
327 if (m == NULL) {
328 IPSECSTAT_INC(ips_out_nomem);
329 key_freesp(&sp);
330 return (ENOBUFS);
331 }
332 in_delayed_cksum(m);
333 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
334 }
335 #if defined(SCTP) || defined(SCTP_SUPPORT)
336 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
337 struct ip *ip;
338
339 m = mb_unmapped_to_ext(m);
340 if (m == NULL) {
341 IPSECSTAT_INC(ips_out_nomem);
342 key_freesp(&sp);
343 return (ENOBUFS);
344 }
345 ip = mtod(m, struct ip *);
346 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
347 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
348 }
349 #endif
350 }
351 /* NB: callee frees mbuf and releases reference to SP */
352 error = ipsec4_process_packet(m, sp, inp);
353 if (error == EJUSTRETURN) {
354 /*
355 * We had a SP with a level of 'use' and no SA. We
356 * will just continue to process the packet without
357 * IPsec processing and return without error.
358 */
359 return (0);
360 }
361 if (error == 0)
362 return (EINPROGRESS); /* consumed by IPsec */
363 return (error);
364 }
365
366 /*
367 * IPSEC_OUTPUT() method implementation for IPv4.
368 * 0 - no IPsec handling needed
369 * other values - mbuf consumed by IPsec.
370 */
371 int
ipsec4_output(struct mbuf * m,struct inpcb * inp)372 ipsec4_output(struct mbuf *m, struct inpcb *inp)
373 {
374
375 /*
376 * If the packet is resubmitted to ip_output (e.g. after
377 * AH, ESP, etc. processing), there will be a tag to bypass
378 * the lookup and related policy checking.
379 */
380 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
381 return (0);
382
383 return (ipsec4_common_output(m, inp, 0));
384 }
385
386 /*
387 * IPSEC_FORWARD() method implementation for IPv4.
388 * 0 - no IPsec handling needed
389 * other values - mbuf consumed by IPsec.
390 */
391 int
ipsec4_forward(struct mbuf * m)392 ipsec4_forward(struct mbuf *m)
393 {
394
395 /*
396 * Check if this packet has an active inbound SP and needs to be
397 * dropped instead of forwarded.
398 */
399 if (ipsec4_in_reject(m, NULL) != 0) {
400 m_freem(m);
401 return (EACCES);
402 }
403 return (ipsec4_common_output(m, NULL, 1));
404 }
405 #endif
406
407 #ifdef INET6
408 static int
in6_sa_equal_addrwithscope(const struct sockaddr_in6 * sa,const struct in6_addr * ia)409 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa,
410 const struct in6_addr *ia)
411 {
412 struct in6_addr ia2;
413
414 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) {
415 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
416 ia2.s6_addr16[1] = htons(sa->sin6_scope_id);
417 return (IN6_ARE_ADDR_EQUAL(ia, &ia2));
418 }
419 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia));
420 }
421
422 static struct secasvar *
ipsec6_allocsa(struct mbuf * m,struct secpolicy * sp,u_int * pidx,int * error)423 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error)
424 {
425 struct secasindex *saidx, tmpsaidx;
426 struct ipsecrequest *isr;
427 struct sockaddr_in6 *sin6;
428 struct secasvar *sav;
429 struct ip6_hdr *ip6;
430
431 /*
432 * Check system global policy controls.
433 */
434 next:
435 isr = sp->req[*pidx];
436 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
437 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
438 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
439 DPRINTF(("%s: IPsec outbound packet dropped due"
440 " to policy (check your sysctls)\n", __func__));
441 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops);
442 *error = EHOSTUNREACH;
443 return (NULL);
444 }
445 /*
446 * Craft SA index to search for proper SA. Note that
447 * we only fillin unspecified SA peers for transport
448 * mode; for tunnel mode they must already be filled in.
449 */
450 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
451 saidx = &tmpsaidx;
452 *saidx = isr->saidx;
453 ip6 = mtod(m, struct ip6_hdr *);
454 if (saidx->src.sin6.sin6_len == 0) {
455 sin6 = (struct sockaddr_in6 *)&saidx->src;
456 sin6->sin6_len = sizeof(*sin6);
457 sin6->sin6_family = AF_INET6;
458 sin6->sin6_port = IPSEC_PORT_ANY;
459 sin6->sin6_addr = ip6->ip6_src;
460 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
461 /* fix scope id for comparing SPD */
462 sin6->sin6_addr.s6_addr16[1] = 0;
463 sin6->sin6_scope_id =
464 ntohs(ip6->ip6_src.s6_addr16[1]);
465 }
466 }
467 if (saidx->dst.sin6.sin6_len == 0) {
468 sin6 = (struct sockaddr_in6 *)&saidx->dst;
469 sin6->sin6_len = sizeof(*sin6);
470 sin6->sin6_family = AF_INET6;
471 sin6->sin6_port = IPSEC_PORT_ANY;
472 sin6->sin6_addr = ip6->ip6_dst;
473 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
474 /* fix scope id for comparing SPD */
475 sin6->sin6_addr.s6_addr16[1] = 0;
476 sin6->sin6_scope_id =
477 ntohs(ip6->ip6_dst.s6_addr16[1]);
478 }
479 }
480 } else
481 saidx = &sp->req[*pidx]->saidx;
482 /*
483 * Lookup SA and validate it.
484 */
485 sav = key_allocsa_policy(sp, saidx, error);
486 if (sav == NULL) {
487 IPSEC6STAT_INC(ips_out_nosa);
488 if (*error != 0)
489 return (NULL);
490 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) {
491 /*
492 * We have no SA and policy that doesn't require
493 * this IPsec transform, thus we can continue w/o
494 * IPsec processing, i.e. return EJUSTRETURN.
495 * But first check if there is some bundled transform.
496 */
497 if (sp->tcount > ++(*pidx))
498 goto next;
499 *error = EJUSTRETURN;
500 }
501 return (NULL);
502 }
503 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform"));
504 return (sav);
505 }
506
507 /*
508 * IPsec output logic for IPv6.
509 */
510 static int
ipsec6_perform_request(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp,u_int idx)511 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp,
512 struct inpcb *inp, u_int idx)
513 {
514 struct ipsec_ctx_data ctx;
515 union sockaddr_union *dst;
516 struct secasvar *sav;
517 struct ip6_hdr *ip6;
518 int error, i, off;
519
520 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx));
521
522 sav = ipsec6_allocsa(m, sp, &idx, &error);
523 if (sav == NULL) {
524 if (error == EJUSTRETURN) { /* No IPsec required */
525 key_freesp(&sp);
526 return (error);
527 }
528 goto bad;
529 }
530
531 /* Fix IP length in case if it is not set yet. */
532 ip6 = mtod(m, struct ip6_hdr *);
533 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
534
535 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE);
536 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
537 goto bad;
538
539 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */
540 dst = &sav->sah->saidx.dst;
541
542 /* Do the appropriate encapsulation, if necessary */
543 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
544 dst->sa.sa_family != AF_INET6 || /* PF mismatch */
545 ((dst->sa.sa_family == AF_INET6) &&
546 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
547 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) {
548 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
549 /* No jumbogram support. */
550 error = ENXIO; /*XXX*/
551 goto bad;
552 }
553 error = ipsec_encap(&m, &sav->sah->saidx);
554 if (error != 0) {
555 DPRINTF(("%s: encapsulation for SPI 0x%08x failed "
556 "with error %d\n", __func__, ntohl(sav->spi),
557 error));
558 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */
559 goto bad;
560 }
561 inp = NULL;
562 }
563
564 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER);
565 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
566 goto bad;
567
568 switch(dst->sa.sa_family) {
569 #ifdef INET
570 case AF_INET:
571 {
572 struct ip *ip;
573 ip = mtod(m, struct ip *);
574 i = ip->ip_hl << 2;
575 off = offsetof(struct ip, ip_p);
576 }
577 break;
578 #endif /* AF_INET */
579 case AF_INET6:
580 i = sizeof(struct ip6_hdr);
581 off = offsetof(struct ip6_hdr, ip6_nxt);
582 break;
583 default:
584 DPRINTF(("%s: unsupported protocol family %u\n",
585 __func__, dst->sa.sa_family));
586 error = EPFNOSUPPORT;
587 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf);
588 goto bad;
589 }
590 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off);
591 return (error);
592 bad:
593 IPSEC6STAT_INC(ips_out_inval);
594 if (m != NULL)
595 m_freem(m);
596 if (sav != NULL)
597 key_freesav(&sav);
598 key_freesp(&sp);
599 return (error);
600 }
601
602 int
ipsec6_process_packet(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp)603 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp,
604 struct inpcb *inp)
605 {
606
607 return (ipsec6_perform_request(m, sp, inp, 0));
608 }
609
610 static int
ipsec6_common_output(struct mbuf * m,struct inpcb * inp,int forwarding)611 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding)
612 {
613 struct secpolicy *sp;
614 int error;
615
616 /* Lookup for the corresponding outbound security policy */
617 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding);
618 if (sp == NULL) {
619 if (error == -EINVAL) {
620 /* Discarded by policy. */
621 m_freem(m);
622 return (EACCES);
623 }
624 return (0); /* No IPsec required. */
625 }
626
627 if (!forwarding) {
628 /*
629 * Do delayed checksums now because we send before
630 * this is done in the normal processing path.
631 */
632 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
633 m = mb_unmapped_to_ext(m);
634 if (m == NULL) {
635 IPSEC6STAT_INC(ips_out_nomem);
636 key_freesp(&sp);
637 return (ENOBUFS);
638 }
639 in6_delayed_cksum(m, m->m_pkthdr.len -
640 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr));
641 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
642 }
643 #if defined(SCTP) || defined(SCTP_SUPPORT)
644 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
645 m = mb_unmapped_to_ext(m);
646 if (m == NULL) {
647 IPSEC6STAT_INC(ips_out_nomem);
648 key_freesp(&sp);
649 return (ENOBUFS);
650 }
651 sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
652 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
653 }
654 #endif
655 }
656 /* NB: callee frees mbuf and releases reference to SP */
657 error = ipsec6_process_packet(m, sp, inp);
658 if (error == EJUSTRETURN) {
659 /*
660 * We had a SP with a level of 'use' and no SA. We
661 * will just continue to process the packet without
662 * IPsec processing and return without error.
663 */
664 return (0);
665 }
666 if (error == 0)
667 return (EINPROGRESS); /* consumed by IPsec */
668 return (error);
669 }
670
671 /*
672 * IPSEC_OUTPUT() method implementation for IPv6.
673 * 0 - no IPsec handling needed
674 * other values - mbuf consumed by IPsec.
675 */
676 int
ipsec6_output(struct mbuf * m,struct inpcb * inp)677 ipsec6_output(struct mbuf *m, struct inpcb *inp)
678 {
679
680 /*
681 * If the packet is resubmitted to ip_output (e.g. after
682 * AH, ESP, etc. processing), there will be a tag to bypass
683 * the lookup and related policy checking.
684 */
685 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
686 return (0);
687
688 return (ipsec6_common_output(m, inp, 0));
689 }
690
691 /*
692 * IPSEC_FORWARD() method implementation for IPv6.
693 * 0 - no IPsec handling needed
694 * other values - mbuf consumed by IPsec.
695 */
696 int
ipsec6_forward(struct mbuf * m)697 ipsec6_forward(struct mbuf *m)
698 {
699
700 /*
701 * Check if this packet has an active inbound SP and needs to be
702 * dropped instead of forwarded.
703 */
704 if (ipsec6_in_reject(m, NULL) != 0) {
705 m_freem(m);
706 return (EACCES);
707 }
708 return (ipsec6_common_output(m, NULL, 1));
709 }
710 #endif /* INET6 */
711
712 int
ipsec_process_done(struct mbuf * m,struct secpolicy * sp,struct secasvar * sav,u_int idx)713 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
714 u_int idx)
715 {
716 struct epoch_tracker et;
717 struct xform_history *xh;
718 struct secasindex *saidx;
719 struct m_tag *mtag;
720 int error;
721
722 saidx = &sav->sah->saidx;
723 switch (saidx->dst.sa.sa_family) {
724 #ifdef INET
725 case AF_INET:
726 /* Fix the header length, for AH processing. */
727 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
728 break;
729 #endif /* INET */
730 #ifdef INET6
731 case AF_INET6:
732 /* Fix the header length, for AH processing. */
733 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
734 error = ENXIO;
735 goto bad;
736 }
737 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
738 /* No jumbogram support. */
739 error = ENXIO; /*?*/
740 goto bad;
741 }
742 mtod(m, struct ip6_hdr *)->ip6_plen =
743 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
744 break;
745 #endif /* INET6 */
746 default:
747 DPRINTF(("%s: unknown protocol family %u\n", __func__,
748 saidx->dst.sa.sa_family));
749 error = ENXIO;
750 goto bad;
751 }
752
753 /*
754 * Add a record of what we've done to the packet.
755 */
756 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT);
757 if (mtag == NULL) {
758 DPRINTF(("%s: could not get packet tag\n", __func__));
759 error = ENOMEM;
760 goto bad;
761 }
762
763 xh = (struct xform_history *)(mtag + 1);
764 xh->dst = saidx->dst;
765 xh->proto = saidx->proto;
766 xh->mode = saidx->mode;
767 xh->spi = sav->spi;
768 m_tag_prepend(m, mtag);
769
770 key_sa_recordxfer(sav, m); /* record data transfer */
771
772 /*
773 * If there's another (bundled) SA to apply, do so.
774 * Note that this puts a burden on the kernel stack size.
775 * If this is a problem we'll need to introduce a queue
776 * to set the packet on so we can unwind the stack before
777 * doing further processing.
778 */
779 if (++idx < sp->tcount) {
780 switch (saidx->dst.sa.sa_family) {
781 #ifdef INET
782 case AF_INET:
783 key_freesav(&sav);
784 IPSECSTAT_INC(ips_out_bundlesa);
785 return (ipsec4_perform_request(m, sp, NULL, idx));
786 /* NOTREACHED */
787 #endif
788 #ifdef INET6
789 case AF_INET6:
790 key_freesav(&sav);
791 IPSEC6STAT_INC(ips_out_bundlesa);
792 return (ipsec6_perform_request(m, sp, NULL, idx));
793 /* NOTREACHED */
794 #endif /* INET6 */
795 default:
796 DPRINTF(("%s: unknown protocol family %u\n", __func__,
797 saidx->dst.sa.sa_family));
798 error = EPFNOSUPPORT;
799 goto bad;
800 }
801 }
802
803 key_freesp(&sp), sp = NULL; /* Release reference to SP */
804 #ifdef INET
805 /*
806 * Do UDP encapsulation if SA requires it.
807 */
808 if (sav->natt != NULL) {
809 error = udp_ipsec_output(m, sav);
810 if (error != 0)
811 goto bad;
812 }
813 #endif /* INET */
814 /*
815 * We're done with IPsec processing, transmit the packet using the
816 * appropriate network protocol (IP or IPv6).
817 */
818 NET_EPOCH_ENTER(et);
819 switch (saidx->dst.sa.sa_family) {
820 #ifdef INET
821 case AF_INET:
822 key_freesav(&sav);
823 error = ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
824 break;
825 #endif /* INET */
826 #ifdef INET6
827 case AF_INET6:
828 key_freesav(&sav);
829 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
830 break;
831 #endif /* INET6 */
832 default:
833 panic("ipsec_process_done");
834 }
835 NET_EPOCH_EXIT(et);
836 return (error);
837 bad:
838 m_freem(m);
839 key_freesav(&sav);
840 if (sp != NULL)
841 key_freesp(&sp);
842 return (error);
843 }
844
845 /*
846 * ipsec_prepend() is optimized version of M_PREPEND().
847 * ipsec_encap() is called by IPsec output routine for tunnel mode SA.
848 * It is expected that after IP encapsulation some IPsec transform will
849 * be performed. Each IPsec transform inserts its variable length header
850 * just after outer IP header using m_makespace(). If given mbuf has not
851 * enough free space at the beginning, we allocate new mbuf and reserve
852 * some space at the beginning and at the end.
853 * This helps avoid allocating of new mbuf and data copying in m_makespace(),
854 * we place outer header in the middle of mbuf's data with reserved leading
855 * and trailing space:
856 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ]
857 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will
858 * be used to inject AH/ESP/IPCOMP header.
859 */
860 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \
861 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \
862 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */))
863 static struct mbuf *
ipsec_prepend(struct mbuf * m,int len,int how)864 ipsec_prepend(struct mbuf *m, int len, int how)
865 {
866 struct mbuf *n;
867
868 M_ASSERTPKTHDR(m);
869 IPSEC_ASSERT(len < MHLEN, ("wrong length"));
870 if (M_LEADINGSPACE(m) >= len) {
871 /* No need to allocate new mbuf. */
872 m->m_data -= len;
873 m->m_len += len;
874 m->m_pkthdr.len += len;
875 return (m);
876 }
877 n = m_gethdr(how, m->m_type);
878 if (n == NULL) {
879 m_freem(m);
880 return (NULL);
881 }
882 m_move_pkthdr(n, m);
883 n->m_next = m;
884 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n))
885 m_align(n, len + IPSEC_TRAILINGSPACE);
886 n->m_len = len;
887 n->m_pkthdr.len += len;
888 return (n);
889 }
890
891 static int
ipsec_encap(struct mbuf ** mp,struct secasindex * saidx)892 ipsec_encap(struct mbuf **mp, struct secasindex *saidx)
893 {
894 #ifdef INET6
895 struct ip6_hdr *ip6;
896 #endif
897 struct ip *ip;
898 int setdf;
899 uint8_t itos, proto;
900
901 ip = mtod(*mp, struct ip *);
902 switch (ip->ip_v) {
903 #ifdef INET
904 case IPVERSION:
905 proto = IPPROTO_IPIP;
906 /*
907 * Collect IP_DF state from the inner header
908 * and honor system-wide control of how to handle it.
909 */
910 switch (V_ip4_ipsec_dfbit) {
911 case 0: /* clear in outer header */
912 case 1: /* set in outer header */
913 setdf = V_ip4_ipsec_dfbit;
914 break;
915 default:/* propagate to outer header */
916 setdf = (ip->ip_off & htons(IP_DF)) != 0;
917 }
918 itos = ip->ip_tos;
919 break;
920 #endif
921 #ifdef INET6
922 case (IPV6_VERSION >> 4):
923 proto = IPPROTO_IPV6;
924 ip6 = mtod(*mp, struct ip6_hdr *);
925 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
926 setdf = V_ip4_ipsec_dfbit ? 1: 0;
927 /* scoped address handling */
928 in6_clearscope(&ip6->ip6_src);
929 in6_clearscope(&ip6->ip6_dst);
930 break;
931 #endif
932 default:
933 return (EAFNOSUPPORT);
934 }
935 switch (saidx->dst.sa.sa_family) {
936 #ifdef INET
937 case AF_INET:
938 if (saidx->src.sa.sa_family != AF_INET ||
939 saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
940 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY)
941 return (EINVAL);
942 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT);
943 if (*mp == NULL)
944 return (ENOBUFS);
945 ip = mtod(*mp, struct ip *);
946 ip->ip_v = IPVERSION;
947 ip->ip_hl = sizeof(struct ip) >> 2;
948 ip->ip_p = proto;
949 ip->ip_len = htons((*mp)->m_pkthdr.len);
950 ip->ip_ttl = V_ip_defttl;
951 ip->ip_sum = 0;
952 ip->ip_off = setdf ? htons(IP_DF): 0;
953 ip->ip_src = saidx->src.sin.sin_addr;
954 ip->ip_dst = saidx->dst.sin.sin_addr;
955 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos);
956 ip_fillid(ip);
957 break;
958 #endif /* INET */
959 #ifdef INET6
960 case AF_INET6:
961 if (saidx->src.sa.sa_family != AF_INET6 ||
962 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) ||
963 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr))
964 return (EINVAL);
965 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT);
966 if (*mp == NULL)
967 return (ENOBUFS);
968 ip6 = mtod(*mp, struct ip6_hdr *);
969 ip6->ip6_flow = 0;
970 ip6->ip6_vfc = IPV6_VERSION;
971 ip6->ip6_hlim = V_ip6_defhlim;
972 ip6->ip6_nxt = proto;
973 ip6->ip6_dst = saidx->dst.sin6.sin6_addr;
974 /* For link-local address embed scope zone id */
975 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
976 ip6->ip6_dst.s6_addr16[1] =
977 htons(saidx->dst.sin6.sin6_scope_id & 0xffff);
978 ip6->ip6_src = saidx->src.sin6.sin6_addr;
979 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
980 ip6->ip6_src.s6_addr16[1] =
981 htons(saidx->src.sin6.sin6_scope_id & 0xffff);
982 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6));
983 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos);
984 ip6->ip6_flow |= htonl((uint32_t)proto << 20);
985 break;
986 #endif /* INET6 */
987 default:
988 return (EAFNOSUPPORT);
989 }
990 (*mp)->m_flags &= ~(M_BCAST | M_MCAST);
991 return (0);
992 }
993