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 in_delayed_cksum(m);
327 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
328 }
329 #if defined(SCTP) || defined(SCTP_SUPPORT)
330 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
331 struct ip *ip;
332
333 ip = mtod(m, struct ip *);
334 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
335 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
336 }
337 #endif
338 }
339 /* NB: callee frees mbuf and releases reference to SP */
340 error = ipsec4_process_packet(m, sp, inp);
341 if (error == EJUSTRETURN) {
342 /*
343 * We had a SP with a level of 'use' and no SA. We
344 * will just continue to process the packet without
345 * IPsec processing and return without error.
346 */
347 return (0);
348 }
349 if (error == 0)
350 return (EINPROGRESS); /* consumed by IPsec */
351 return (error);
352 }
353
354 /*
355 * IPSEC_OUTPUT() method implementation for IPv4.
356 * 0 - no IPsec handling needed
357 * other values - mbuf consumed by IPsec.
358 */
359 int
ipsec4_output(struct mbuf * m,struct inpcb * inp)360 ipsec4_output(struct mbuf *m, struct inpcb *inp)
361 {
362
363 /*
364 * If the packet is resubmitted to ip_output (e.g. after
365 * AH, ESP, etc. processing), there will be a tag to bypass
366 * the lookup and related policy checking.
367 */
368 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
369 return (0);
370
371 return (ipsec4_common_output(m, inp, 0));
372 }
373
374 /*
375 * IPSEC_FORWARD() method implementation for IPv4.
376 * 0 - no IPsec handling needed
377 * other values - mbuf consumed by IPsec.
378 */
379 int
ipsec4_forward(struct mbuf * m)380 ipsec4_forward(struct mbuf *m)
381 {
382
383 /*
384 * Check if this packet has an active inbound SP and needs to be
385 * dropped instead of forwarded.
386 */
387 if (ipsec4_in_reject(m, NULL) != 0) {
388 m_freem(m);
389 return (EACCES);
390 }
391 return (ipsec4_common_output(m, NULL, 1));
392 }
393 #endif
394
395 #ifdef INET6
396 static int
in6_sa_equal_addrwithscope(const struct sockaddr_in6 * sa,const struct in6_addr * ia)397 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa,
398 const struct in6_addr *ia)
399 {
400 struct in6_addr ia2;
401
402 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) {
403 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
404 ia2.s6_addr16[1] = htons(sa->sin6_scope_id);
405 return (IN6_ARE_ADDR_EQUAL(ia, &ia2));
406 }
407 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia));
408 }
409
410 static struct secasvar *
ipsec6_allocsa(struct mbuf * m,struct secpolicy * sp,u_int * pidx,int * error)411 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error)
412 {
413 struct secasindex *saidx, tmpsaidx;
414 struct ipsecrequest *isr;
415 struct sockaddr_in6 *sin6;
416 struct secasvar *sav;
417 struct ip6_hdr *ip6;
418
419 /*
420 * Check system global policy controls.
421 */
422 next:
423 isr = sp->req[*pidx];
424 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
425 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
426 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
427 DPRINTF(("%s: IPsec outbound packet dropped due"
428 " to policy (check your sysctls)\n", __func__));
429 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops);
430 *error = EHOSTUNREACH;
431 return (NULL);
432 }
433 /*
434 * Craft SA index to search for proper SA. Note that
435 * we only fillin unspecified SA peers for transport
436 * mode; for tunnel mode they must already be filled in.
437 */
438 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
439 saidx = &tmpsaidx;
440 *saidx = isr->saidx;
441 ip6 = mtod(m, struct ip6_hdr *);
442 if (saidx->src.sin6.sin6_len == 0) {
443 sin6 = (struct sockaddr_in6 *)&saidx->src;
444 sin6->sin6_len = sizeof(*sin6);
445 sin6->sin6_family = AF_INET6;
446 sin6->sin6_port = IPSEC_PORT_ANY;
447 sin6->sin6_addr = ip6->ip6_src;
448 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
449 /* fix scope id for comparing SPD */
450 sin6->sin6_addr.s6_addr16[1] = 0;
451 sin6->sin6_scope_id =
452 ntohs(ip6->ip6_src.s6_addr16[1]);
453 }
454 }
455 if (saidx->dst.sin6.sin6_len == 0) {
456 sin6 = (struct sockaddr_in6 *)&saidx->dst;
457 sin6->sin6_len = sizeof(*sin6);
458 sin6->sin6_family = AF_INET6;
459 sin6->sin6_port = IPSEC_PORT_ANY;
460 sin6->sin6_addr = ip6->ip6_dst;
461 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
462 /* fix scope id for comparing SPD */
463 sin6->sin6_addr.s6_addr16[1] = 0;
464 sin6->sin6_scope_id =
465 ntohs(ip6->ip6_dst.s6_addr16[1]);
466 }
467 }
468 } else
469 saidx = &sp->req[*pidx]->saidx;
470 /*
471 * Lookup SA and validate it.
472 */
473 sav = key_allocsa_policy(sp, saidx, error);
474 if (sav == NULL) {
475 IPSEC6STAT_INC(ips_out_nosa);
476 if (*error != 0)
477 return (NULL);
478 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) {
479 /*
480 * We have no SA and policy that doesn't require
481 * this IPsec transform, thus we can continue w/o
482 * IPsec processing, i.e. return EJUSTRETURN.
483 * But first check if there is some bundled transform.
484 */
485 if (sp->tcount > ++(*pidx))
486 goto next;
487 *error = EJUSTRETURN;
488 }
489 return (NULL);
490 }
491 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform"));
492 return (sav);
493 }
494
495 /*
496 * IPsec output logic for IPv6.
497 */
498 static int
ipsec6_perform_request(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp,u_int idx)499 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp,
500 struct inpcb *inp, u_int idx)
501 {
502 struct ipsec_ctx_data ctx;
503 union sockaddr_union *dst;
504 struct secasvar *sav;
505 struct ip6_hdr *ip6;
506 int error, i, off;
507
508 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx));
509
510 sav = ipsec6_allocsa(m, sp, &idx, &error);
511 if (sav == NULL) {
512 if (error == EJUSTRETURN) { /* No IPsec required */
513 key_freesp(&sp);
514 return (error);
515 }
516 goto bad;
517 }
518
519 /* Fix IP length in case if it is not set yet. */
520 ip6 = mtod(m, struct ip6_hdr *);
521 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
522
523 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE);
524 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
525 goto bad;
526
527 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */
528 dst = &sav->sah->saidx.dst;
529
530 /* Do the appropriate encapsulation, if necessary */
531 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
532 dst->sa.sa_family != AF_INET6 || /* PF mismatch */
533 ((dst->sa.sa_family == AF_INET6) &&
534 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
535 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) {
536 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
537 /* No jumbogram support. */
538 error = ENXIO; /*XXX*/
539 goto bad;
540 }
541 error = ipsec_encap(&m, &sav->sah->saidx);
542 if (error != 0) {
543 DPRINTF(("%s: encapsulation for SPI 0x%08x failed "
544 "with error %d\n", __func__, ntohl(sav->spi),
545 error));
546 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */
547 goto bad;
548 }
549 inp = NULL;
550 }
551
552 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER);
553 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
554 goto bad;
555
556 switch(dst->sa.sa_family) {
557 #ifdef INET
558 case AF_INET:
559 {
560 struct ip *ip;
561 ip = mtod(m, struct ip *);
562 i = ip->ip_hl << 2;
563 off = offsetof(struct ip, ip_p);
564 }
565 break;
566 #endif /* AF_INET */
567 case AF_INET6:
568 i = sizeof(struct ip6_hdr);
569 off = offsetof(struct ip6_hdr, ip6_nxt);
570 break;
571 default:
572 DPRINTF(("%s: unsupported protocol family %u\n",
573 __func__, dst->sa.sa_family));
574 error = EPFNOSUPPORT;
575 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf);
576 goto bad;
577 }
578 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off);
579 return (error);
580 bad:
581 IPSEC6STAT_INC(ips_out_inval);
582 if (m != NULL)
583 m_freem(m);
584 if (sav != NULL)
585 key_freesav(&sav);
586 key_freesp(&sp);
587 return (error);
588 }
589
590 int
ipsec6_process_packet(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp)591 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp,
592 struct inpcb *inp)
593 {
594
595 return (ipsec6_perform_request(m, sp, inp, 0));
596 }
597
598 static int
ipsec6_common_output(struct mbuf * m,struct inpcb * inp,int forwarding)599 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding)
600 {
601 struct secpolicy *sp;
602 int error;
603
604 /* Lookup for the corresponding outbound security policy */
605 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding);
606 if (sp == NULL) {
607 if (error == -EINVAL) {
608 /* Discarded by policy. */
609 m_freem(m);
610 return (EACCES);
611 }
612 return (0); /* No IPsec required. */
613 }
614
615 if (!forwarding) {
616 /*
617 * Do delayed checksums now because we send before
618 * this is done in the normal processing path.
619 */
620 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
621 in6_delayed_cksum(m, m->m_pkthdr.len -
622 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr));
623 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
624 }
625 #if defined(SCTP) || defined(SCTP_SUPPORT)
626 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
627 sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
628 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
629 }
630 #endif
631 }
632 /* NB: callee frees mbuf and releases reference to SP */
633 error = ipsec6_process_packet(m, sp, inp);
634 if (error == EJUSTRETURN) {
635 /*
636 * We had a SP with a level of 'use' and no SA. We
637 * will just continue to process the packet without
638 * IPsec processing and return without error.
639 */
640 return (0);
641 }
642 if (error == 0)
643 return (EINPROGRESS); /* consumed by IPsec */
644 return (error);
645 }
646
647 /*
648 * IPSEC_OUTPUT() method implementation for IPv6.
649 * 0 - no IPsec handling needed
650 * other values - mbuf consumed by IPsec.
651 */
652 int
ipsec6_output(struct mbuf * m,struct inpcb * inp)653 ipsec6_output(struct mbuf *m, struct inpcb *inp)
654 {
655
656 /*
657 * If the packet is resubmitted to ip_output (e.g. after
658 * AH, ESP, etc. processing), there will be a tag to bypass
659 * the lookup and related policy checking.
660 */
661 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
662 return (0);
663
664 return (ipsec6_common_output(m, inp, 0));
665 }
666
667 /*
668 * IPSEC_FORWARD() method implementation for IPv6.
669 * 0 - no IPsec handling needed
670 * other values - mbuf consumed by IPsec.
671 */
672 int
ipsec6_forward(struct mbuf * m)673 ipsec6_forward(struct mbuf *m)
674 {
675
676 /*
677 * Check if this packet has an active inbound SP and needs to be
678 * dropped instead of forwarded.
679 */
680 if (ipsec6_in_reject(m, NULL) != 0) {
681 m_freem(m);
682 return (EACCES);
683 }
684 return (ipsec6_common_output(m, NULL, 1));
685 }
686 #endif /* INET6 */
687
688 int
ipsec_process_done(struct mbuf * m,struct secpolicy * sp,struct secasvar * sav,u_int idx)689 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
690 u_int idx)
691 {
692 struct epoch_tracker et;
693 struct xform_history *xh;
694 struct secasindex *saidx;
695 struct m_tag *mtag;
696 int error;
697
698 saidx = &sav->sah->saidx;
699 switch (saidx->dst.sa.sa_family) {
700 #ifdef INET
701 case AF_INET:
702 /* Fix the header length, for AH processing. */
703 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
704 break;
705 #endif /* INET */
706 #ifdef INET6
707 case AF_INET6:
708 /* Fix the header length, for AH processing. */
709 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
710 error = ENXIO;
711 goto bad;
712 }
713 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
714 /* No jumbogram support. */
715 error = ENXIO; /*?*/
716 goto bad;
717 }
718 mtod(m, struct ip6_hdr *)->ip6_plen =
719 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
720 break;
721 #endif /* INET6 */
722 default:
723 DPRINTF(("%s: unknown protocol family %u\n", __func__,
724 saidx->dst.sa.sa_family));
725 error = ENXIO;
726 goto bad;
727 }
728
729 /*
730 * Add a record of what we've done to the packet.
731 */
732 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT);
733 if (mtag == NULL) {
734 DPRINTF(("%s: could not get packet tag\n", __func__));
735 error = ENOMEM;
736 goto bad;
737 }
738
739 xh = (struct xform_history *)(mtag + 1);
740 xh->dst = saidx->dst;
741 xh->proto = saidx->proto;
742 xh->mode = saidx->mode;
743 xh->spi = sav->spi;
744 m_tag_prepend(m, mtag);
745
746 key_sa_recordxfer(sav, m); /* record data transfer */
747
748 /*
749 * If there's another (bundled) SA to apply, do so.
750 * Note that this puts a burden on the kernel stack size.
751 * If this is a problem we'll need to introduce a queue
752 * to set the packet on so we can unwind the stack before
753 * doing further processing.
754 */
755 if (++idx < sp->tcount) {
756 switch (saidx->dst.sa.sa_family) {
757 #ifdef INET
758 case AF_INET:
759 key_freesav(&sav);
760 IPSECSTAT_INC(ips_out_bundlesa);
761 return (ipsec4_perform_request(m, sp, NULL, idx));
762 /* NOTREACHED */
763 #endif
764 #ifdef INET6
765 case AF_INET6:
766 key_freesav(&sav);
767 IPSEC6STAT_INC(ips_out_bundlesa);
768 return (ipsec6_perform_request(m, sp, NULL, idx));
769 /* NOTREACHED */
770 #endif /* INET6 */
771 default:
772 DPRINTF(("%s: unknown protocol family %u\n", __func__,
773 saidx->dst.sa.sa_family));
774 error = EPFNOSUPPORT;
775 goto bad;
776 }
777 }
778
779 key_freesp(&sp), sp = NULL; /* Release reference to SP */
780 #ifdef INET
781 /*
782 * Do UDP encapsulation if SA requires it.
783 */
784 if (sav->natt != NULL) {
785 error = udp_ipsec_output(m, sav);
786 if (error != 0)
787 goto bad;
788 }
789 #endif /* INET */
790 /*
791 * We're done with IPsec processing, transmit the packet using the
792 * appropriate network protocol (IP or IPv6).
793 */
794 NET_EPOCH_ENTER(et);
795 switch (saidx->dst.sa.sa_family) {
796 #ifdef INET
797 case AF_INET:
798 key_freesav(&sav);
799 error = ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
800 break;
801 #endif /* INET */
802 #ifdef INET6
803 case AF_INET6:
804 key_freesav(&sav);
805 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
806 break;
807 #endif /* INET6 */
808 default:
809 panic("ipsec_process_done");
810 }
811 NET_EPOCH_EXIT(et);
812 return (error);
813 bad:
814 m_freem(m);
815 key_freesav(&sav);
816 if (sp != NULL)
817 key_freesp(&sp);
818 return (error);
819 }
820
821 /*
822 * ipsec_prepend() is optimized version of M_PREPEND().
823 * ipsec_encap() is called by IPsec output routine for tunnel mode SA.
824 * It is expected that after IP encapsulation some IPsec transform will
825 * be performed. Each IPsec transform inserts its variable length header
826 * just after outer IP header using m_makespace(). If given mbuf has not
827 * enough free space at the beginning, we allocate new mbuf and reserve
828 * some space at the beginning and at the end.
829 * This helps avoid allocating of new mbuf and data copying in m_makespace(),
830 * we place outer header in the middle of mbuf's data with reserved leading
831 * and trailing space:
832 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ]
833 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will
834 * be used to inject AH/ESP/IPCOMP header.
835 */
836 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \
837 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \
838 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */))
839 static struct mbuf *
ipsec_prepend(struct mbuf * m,int len,int how)840 ipsec_prepend(struct mbuf *m, int len, int how)
841 {
842 struct mbuf *n;
843
844 M_ASSERTPKTHDR(m);
845 IPSEC_ASSERT(len < MHLEN, ("wrong length"));
846 if (M_LEADINGSPACE(m) >= len) {
847 /* No need to allocate new mbuf. */
848 m->m_data -= len;
849 m->m_len += len;
850 m->m_pkthdr.len += len;
851 return (m);
852 }
853 n = m_gethdr(how, m->m_type);
854 if (n == NULL) {
855 m_freem(m);
856 return (NULL);
857 }
858 m_move_pkthdr(n, m);
859 n->m_next = m;
860 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n))
861 m_align(n, len + IPSEC_TRAILINGSPACE);
862 n->m_len = len;
863 n->m_pkthdr.len += len;
864 return (n);
865 }
866
867 static int
ipsec_encap(struct mbuf ** mp,struct secasindex * saidx)868 ipsec_encap(struct mbuf **mp, struct secasindex *saidx)
869 {
870 #ifdef INET6
871 struct ip6_hdr *ip6;
872 #endif
873 struct ip *ip;
874 int setdf;
875 uint8_t itos, proto;
876
877 ip = mtod(*mp, struct ip *);
878 switch (ip->ip_v) {
879 #ifdef INET
880 case IPVERSION:
881 proto = IPPROTO_IPIP;
882 /*
883 * Collect IP_DF state from the inner header
884 * and honor system-wide control of how to handle it.
885 */
886 switch (V_ip4_ipsec_dfbit) {
887 case 0: /* clear in outer header */
888 case 1: /* set in outer header */
889 setdf = V_ip4_ipsec_dfbit;
890 break;
891 default:/* propagate to outer header */
892 setdf = (ip->ip_off & htons(IP_DF)) != 0;
893 }
894 itos = ip->ip_tos;
895 break;
896 #endif
897 #ifdef INET6
898 case (IPV6_VERSION >> 4):
899 proto = IPPROTO_IPV6;
900 ip6 = mtod(*mp, struct ip6_hdr *);
901 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
902 setdf = V_ip4_ipsec_dfbit ? 1: 0;
903 /* scoped address handling */
904 in6_clearscope(&ip6->ip6_src);
905 in6_clearscope(&ip6->ip6_dst);
906 break;
907 #endif
908 default:
909 return (EAFNOSUPPORT);
910 }
911 switch (saidx->dst.sa.sa_family) {
912 #ifdef INET
913 case AF_INET:
914 if (saidx->src.sa.sa_family != AF_INET ||
915 saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
916 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY)
917 return (EINVAL);
918 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT);
919 if (*mp == NULL)
920 return (ENOBUFS);
921 ip = mtod(*mp, struct ip *);
922 ip->ip_v = IPVERSION;
923 ip->ip_hl = sizeof(struct ip) >> 2;
924 ip->ip_p = proto;
925 ip->ip_len = htons((*mp)->m_pkthdr.len);
926 ip->ip_ttl = V_ip_defttl;
927 ip->ip_sum = 0;
928 ip->ip_off = setdf ? htons(IP_DF): 0;
929 ip->ip_src = saidx->src.sin.sin_addr;
930 ip->ip_dst = saidx->dst.sin.sin_addr;
931 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos);
932 ip_fillid(ip);
933 break;
934 #endif /* INET */
935 #ifdef INET6
936 case AF_INET6:
937 if (saidx->src.sa.sa_family != AF_INET6 ||
938 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) ||
939 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr))
940 return (EINVAL);
941 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT);
942 if (*mp == NULL)
943 return (ENOBUFS);
944 ip6 = mtod(*mp, struct ip6_hdr *);
945 ip6->ip6_flow = 0;
946 ip6->ip6_vfc = IPV6_VERSION;
947 ip6->ip6_hlim = V_ip6_defhlim;
948 ip6->ip6_nxt = proto;
949 ip6->ip6_dst = saidx->dst.sin6.sin6_addr;
950 /* For link-local address embed scope zone id */
951 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
952 ip6->ip6_dst.s6_addr16[1] =
953 htons(saidx->dst.sin6.sin6_scope_id & 0xffff);
954 ip6->ip6_src = saidx->src.sin6.sin6_addr;
955 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
956 ip6->ip6_src.s6_addr16[1] =
957 htons(saidx->src.sin6.sin6_scope_id & 0xffff);
958 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6));
959 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos);
960 ip6->ip6_flow |= htonl((uint32_t)proto << 20);
961 break;
962 #endif /* INET6 */
963 default:
964 return (EAFNOSUPPORT);
965 }
966 (*mp)->m_flags &= ~(M_BCAST | M_MCAST);
967 return (0);
968 }
969