1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
5 * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
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
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 #if defined(SCTP) || defined(SCTP_SUPPORT)
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 *
ipsec4_allocsa(struct mbuf * m,struct secpolicy * sp,u_int * pidx,int * error)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
ipsec4_perform_request(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp,u_int idx)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
ipsec4_process_packet(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp)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
ipsec4_common_output(struct mbuf * m,struct inpcb * inp,int forwarding)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 #if defined(SCTP) || defined(SCTP_SUPPORT)
328 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
329 struct ip *ip;
330
331 ip = mtod(m, struct ip *);
332 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
333 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
334 }
335 #endif
336 }
337 /* NB: callee frees mbuf and releases reference to SP */
338 error = ipsec4_process_packet(m, sp, inp);
339 if (error == EJUSTRETURN) {
340 /*
341 * We had a SP with a level of 'use' and no SA. We
342 * will just continue to process the packet without
343 * IPsec processing and return without error.
344 */
345 return (0);
346 }
347 if (error == 0)
348 return (EINPROGRESS); /* consumed by IPsec */
349 return (error);
350 }
351
352 /*
353 * IPSEC_OUTPUT() method implementation for IPv4.
354 * 0 - no IPsec handling needed
355 * other values - mbuf consumed by IPsec.
356 */
357 int
ipsec4_output(struct mbuf * m,struct inpcb * inp)358 ipsec4_output(struct mbuf *m, struct inpcb *inp)
359 {
360
361 /*
362 * If the packet is resubmitted to ip_output (e.g. after
363 * AH, ESP, etc. processing), there will be a tag to bypass
364 * the lookup and related policy checking.
365 */
366 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
367 return (0);
368
369 return (ipsec4_common_output(m, inp, 0));
370 }
371
372 /*
373 * IPSEC_FORWARD() method implementation for IPv4.
374 * 0 - no IPsec handling needed
375 * other values - mbuf consumed by IPsec.
376 */
377 int
ipsec4_forward(struct mbuf * m)378 ipsec4_forward(struct mbuf *m)
379 {
380
381 /*
382 * Check if this packet has an active inbound SP and needs to be
383 * dropped instead of forwarded.
384 */
385 if (ipsec4_in_reject(m, NULL) != 0) {
386 m_freem(m);
387 return (EACCES);
388 }
389 return (ipsec4_common_output(m, NULL, 1));
390 }
391 #endif
392
393 #ifdef INET6
394 static int
in6_sa_equal_addrwithscope(const struct sockaddr_in6 * sa,const struct in6_addr * ia)395 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa,
396 const struct in6_addr *ia)
397 {
398 struct in6_addr ia2;
399
400 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) {
401 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
402 ia2.s6_addr16[1] = htons(sa->sin6_scope_id);
403 return (IN6_ARE_ADDR_EQUAL(ia, &ia2));
404 }
405 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia));
406 }
407
408 static struct secasvar *
ipsec6_allocsa(struct mbuf * m,struct secpolicy * sp,u_int * pidx,int * error)409 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error)
410 {
411 struct secasindex *saidx, tmpsaidx;
412 struct ipsecrequest *isr;
413 struct sockaddr_in6 *sin6;
414 struct secasvar *sav;
415 struct ip6_hdr *ip6;
416
417 /*
418 * Check system global policy controls.
419 */
420 next:
421 isr = sp->req[*pidx];
422 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
423 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
424 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
425 DPRINTF(("%s: IPsec outbound packet dropped due"
426 " to policy (check your sysctls)\n", __func__));
427 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops);
428 *error = EHOSTUNREACH;
429 return (NULL);
430 }
431 /*
432 * Craft SA index to search for proper SA. Note that
433 * we only fillin unspecified SA peers for transport
434 * mode; for tunnel mode they must already be filled in.
435 */
436 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
437 saidx = &tmpsaidx;
438 *saidx = isr->saidx;
439 ip6 = mtod(m, struct ip6_hdr *);
440 if (saidx->src.sin6.sin6_len == 0) {
441 sin6 = (struct sockaddr_in6 *)&saidx->src;
442 sin6->sin6_len = sizeof(*sin6);
443 sin6->sin6_family = AF_INET6;
444 sin6->sin6_port = IPSEC_PORT_ANY;
445 sin6->sin6_addr = ip6->ip6_src;
446 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
447 /* fix scope id for comparing SPD */
448 sin6->sin6_addr.s6_addr16[1] = 0;
449 sin6->sin6_scope_id =
450 ntohs(ip6->ip6_src.s6_addr16[1]);
451 }
452 }
453 if (saidx->dst.sin6.sin6_len == 0) {
454 sin6 = (struct sockaddr_in6 *)&saidx->dst;
455 sin6->sin6_len = sizeof(*sin6);
456 sin6->sin6_family = AF_INET6;
457 sin6->sin6_port = IPSEC_PORT_ANY;
458 sin6->sin6_addr = ip6->ip6_dst;
459 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
460 /* fix scope id for comparing SPD */
461 sin6->sin6_addr.s6_addr16[1] = 0;
462 sin6->sin6_scope_id =
463 ntohs(ip6->ip6_dst.s6_addr16[1]);
464 }
465 }
466 } else
467 saidx = &sp->req[*pidx]->saidx;
468 /*
469 * Lookup SA and validate it.
470 */
471 sav = key_allocsa_policy(sp, saidx, error);
472 if (sav == NULL) {
473 IPSEC6STAT_INC(ips_out_nosa);
474 if (*error != 0)
475 return (NULL);
476 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) {
477 /*
478 * We have no SA and policy that doesn't require
479 * this IPsec transform, thus we can continue w/o
480 * IPsec processing, i.e. return EJUSTRETURN.
481 * But first check if there is some bundled transform.
482 */
483 if (sp->tcount > ++(*pidx))
484 goto next;
485 *error = EJUSTRETURN;
486 }
487 return (NULL);
488 }
489 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform"));
490 return (sav);
491 }
492
493 /*
494 * IPsec output logic for IPv6.
495 */
496 static int
ipsec6_perform_request(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp,u_int idx)497 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp,
498 struct inpcb *inp, u_int idx)
499 {
500 struct ipsec_ctx_data ctx;
501 union sockaddr_union *dst;
502 struct secasvar *sav;
503 struct ip6_hdr *ip6;
504 int error, i, off;
505
506 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx));
507
508 sav = ipsec6_allocsa(m, sp, &idx, &error);
509 if (sav == NULL) {
510 if (error == EJUSTRETURN) { /* No IPsec required */
511 key_freesp(&sp);
512 return (error);
513 }
514 goto bad;
515 }
516
517 /* Fix IP length in case if it is not set yet. */
518 ip6 = mtod(m, struct ip6_hdr *);
519 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
520
521 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE);
522 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
523 goto bad;
524
525 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */
526 dst = &sav->sah->saidx.dst;
527
528 /* Do the appropriate encapsulation, if necessary */
529 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
530 dst->sa.sa_family != AF_INET6 || /* PF mismatch */
531 ((dst->sa.sa_family == AF_INET6) &&
532 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
533 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) {
534 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
535 /* No jumbogram support. */
536 error = ENXIO; /*XXX*/
537 goto bad;
538 }
539 error = ipsec_encap(&m, &sav->sah->saidx);
540 if (error != 0) {
541 DPRINTF(("%s: encapsulation for SPI 0x%08x failed "
542 "with error %d\n", __func__, ntohl(sav->spi),
543 error));
544 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */
545 goto bad;
546 }
547 inp = NULL;
548 }
549
550 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER);
551 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0)
552 goto bad;
553
554 switch(dst->sa.sa_family) {
555 #ifdef INET
556 case AF_INET:
557 {
558 struct ip *ip;
559 ip = mtod(m, struct ip *);
560 i = ip->ip_hl << 2;
561 off = offsetof(struct ip, ip_p);
562 }
563 break;
564 #endif /* AF_INET */
565 case AF_INET6:
566 i = sizeof(struct ip6_hdr);
567 off = offsetof(struct ip6_hdr, ip6_nxt);
568 break;
569 default:
570 DPRINTF(("%s: unsupported protocol family %u\n",
571 __func__, dst->sa.sa_family));
572 error = EPFNOSUPPORT;
573 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf);
574 goto bad;
575 }
576 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off);
577 return (error);
578 bad:
579 IPSEC6STAT_INC(ips_out_inval);
580 if (m != NULL)
581 m_freem(m);
582 if (sav != NULL)
583 key_freesav(&sav);
584 key_freesp(&sp);
585 return (error);
586 }
587
588 int
ipsec6_process_packet(struct mbuf * m,struct secpolicy * sp,struct inpcb * inp)589 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp,
590 struct inpcb *inp)
591 {
592
593 return (ipsec6_perform_request(m, sp, inp, 0));
594 }
595
596 static int
ipsec6_common_output(struct mbuf * m,struct inpcb * inp,int forwarding)597 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding)
598 {
599 struct secpolicy *sp;
600 int error;
601
602 /* Lookup for the corresponding outbound security policy */
603 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding);
604 if (sp == NULL) {
605 if (error == -EINVAL) {
606 /* Discarded by policy. */
607 m_freem(m);
608 return (EACCES);
609 }
610 return (0); /* No IPsec required. */
611 }
612
613 if (!forwarding) {
614 /*
615 * Do delayed checksums now because we send before
616 * this is done in the normal processing path.
617 */
618 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
619 in6_delayed_cksum(m, m->m_pkthdr.len -
620 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr));
621 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
622 }
623 #if defined(SCTP) || defined(SCTP_SUPPORT)
624 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
625 sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
626 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
627 }
628 #endif
629 }
630 /* NB: callee frees mbuf and releases reference to SP */
631 error = ipsec6_process_packet(m, sp, inp);
632 if (error == EJUSTRETURN) {
633 /*
634 * We had a SP with a level of 'use' and no SA. We
635 * will just continue to process the packet without
636 * IPsec processing and return without error.
637 */
638 return (0);
639 }
640 if (error == 0)
641 return (EINPROGRESS); /* consumed by IPsec */
642 return (error);
643 }
644
645 /*
646 * IPSEC_OUTPUT() method implementation for IPv6.
647 * 0 - no IPsec handling needed
648 * other values - mbuf consumed by IPsec.
649 */
650 int
ipsec6_output(struct mbuf * m,struct inpcb * inp)651 ipsec6_output(struct mbuf *m, struct inpcb *inp)
652 {
653
654 /*
655 * If the packet is resubmitted to ip_output (e.g. after
656 * AH, ESP, etc. processing), there will be a tag to bypass
657 * the lookup and related policy checking.
658 */
659 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL)
660 return (0);
661
662 return (ipsec6_common_output(m, inp, 0));
663 }
664
665 /*
666 * IPSEC_FORWARD() method implementation for IPv6.
667 * 0 - no IPsec handling needed
668 * other values - mbuf consumed by IPsec.
669 */
670 int
ipsec6_forward(struct mbuf * m)671 ipsec6_forward(struct mbuf *m)
672 {
673
674 /*
675 * Check if this packet has an active inbound SP and needs to be
676 * dropped instead of forwarded.
677 */
678 if (ipsec6_in_reject(m, NULL) != 0) {
679 m_freem(m);
680 return (EACCES);
681 }
682 return (ipsec6_common_output(m, NULL, 1));
683 }
684 #endif /* INET6 */
685
686 int
ipsec_process_done(struct mbuf * m,struct secpolicy * sp,struct secasvar * sav,u_int idx)687 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
688 u_int idx)
689 {
690 struct epoch_tracker et;
691 struct xform_history *xh;
692 struct secasindex *saidx;
693 struct m_tag *mtag;
694 int error;
695
696 saidx = &sav->sah->saidx;
697 switch (saidx->dst.sa.sa_family) {
698 #ifdef INET
699 case AF_INET:
700 /* Fix the header length, for AH processing. */
701 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
702 break;
703 #endif /* INET */
704 #ifdef INET6
705 case AF_INET6:
706 /* Fix the header length, for AH processing. */
707 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
708 error = ENXIO;
709 goto bad;
710 }
711 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
712 /* No jumbogram support. */
713 error = ENXIO; /*?*/
714 goto bad;
715 }
716 mtod(m, struct ip6_hdr *)->ip6_plen =
717 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
718 break;
719 #endif /* INET6 */
720 default:
721 DPRINTF(("%s: unknown protocol family %u\n", __func__,
722 saidx->dst.sa.sa_family));
723 error = ENXIO;
724 goto bad;
725 }
726
727 /*
728 * Add a record of what we've done to the packet.
729 */
730 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT);
731 if (mtag == NULL) {
732 DPRINTF(("%s: could not get packet tag\n", __func__));
733 error = ENOMEM;
734 goto bad;
735 }
736
737 xh = (struct xform_history *)(mtag + 1);
738 xh->dst = saidx->dst;
739 xh->proto = saidx->proto;
740 xh->mode = saidx->mode;
741 xh->spi = sav->spi;
742 m_tag_prepend(m, mtag);
743
744 key_sa_recordxfer(sav, m); /* record data transfer */
745
746 /*
747 * If there's another (bundled) SA to apply, do so.
748 * Note that this puts a burden on the kernel stack size.
749 * If this is a problem we'll need to introduce a queue
750 * to set the packet on so we can unwind the stack before
751 * doing further processing.
752 */
753 if (++idx < sp->tcount) {
754 switch (saidx->dst.sa.sa_family) {
755 #ifdef INET
756 case AF_INET:
757 key_freesav(&sav);
758 IPSECSTAT_INC(ips_out_bundlesa);
759 return (ipsec4_perform_request(m, sp, NULL, idx));
760 /* NOTREACHED */
761 #endif
762 #ifdef INET6
763 case AF_INET6:
764 key_freesav(&sav);
765 IPSEC6STAT_INC(ips_out_bundlesa);
766 return (ipsec6_perform_request(m, sp, NULL, idx));
767 /* NOTREACHED */
768 #endif /* INET6 */
769 default:
770 DPRINTF(("%s: unknown protocol family %u\n", __func__,
771 saidx->dst.sa.sa_family));
772 error = EPFNOSUPPORT;
773 goto bad;
774 }
775 }
776
777 key_freesp(&sp), sp = NULL; /* Release reference to SP */
778 #ifdef INET
779 /*
780 * Do UDP encapsulation if SA requires it.
781 */
782 if (sav->natt != NULL) {
783 error = udp_ipsec_output(m, sav);
784 if (error != 0)
785 goto bad;
786 }
787 #endif /* INET */
788 /*
789 * We're done with IPsec processing, transmit the packet using the
790 * appropriate network protocol (IP or IPv6).
791 */
792 NET_EPOCH_ENTER(et);
793 switch (saidx->dst.sa.sa_family) {
794 #ifdef INET
795 case AF_INET:
796 key_freesav(&sav);
797 error = ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
798 break;
799 #endif /* INET */
800 #ifdef INET6
801 case AF_INET6:
802 key_freesav(&sav);
803 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
804 break;
805 #endif /* INET6 */
806 default:
807 panic("ipsec_process_done");
808 }
809 NET_EPOCH_EXIT(et);
810 return (error);
811 bad:
812 m_freem(m);
813 key_freesav(&sav);
814 if (sp != NULL)
815 key_freesp(&sp);
816 return (error);
817 }
818
819 /*
820 * ipsec_prepend() is optimized version of M_PREPEND().
821 * ipsec_encap() is called by IPsec output routine for tunnel mode SA.
822 * It is expected that after IP encapsulation some IPsec transform will
823 * be performed. Each IPsec transform inserts its variable length header
824 * just after outer IP header using m_makespace(). If given mbuf has not
825 * enough free space at the beginning, we allocate new mbuf and reserve
826 * some space at the beginning and at the end.
827 * This helps avoid allocating of new mbuf and data copying in m_makespace(),
828 * we place outer header in the middle of mbuf's data with reserved leading
829 * and trailing space:
830 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ]
831 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will
832 * be used to inject AH/ESP/IPCOMP header.
833 */
834 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \
835 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \
836 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */))
837 static struct mbuf *
ipsec_prepend(struct mbuf * m,int len,int how)838 ipsec_prepend(struct mbuf *m, int len, int how)
839 {
840 struct mbuf *n;
841
842 M_ASSERTPKTHDR(m);
843 IPSEC_ASSERT(len < MHLEN, ("wrong length"));
844 if (M_LEADINGSPACE(m) >= len) {
845 /* No need to allocate new mbuf. */
846 m->m_data -= len;
847 m->m_len += len;
848 m->m_pkthdr.len += len;
849 return (m);
850 }
851 n = m_gethdr(how, m->m_type);
852 if (n == NULL) {
853 m_freem(m);
854 return (NULL);
855 }
856 m_move_pkthdr(n, m);
857 n->m_next = m;
858 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n))
859 m_align(n, len + IPSEC_TRAILINGSPACE);
860 n->m_len = len;
861 n->m_pkthdr.len += len;
862 return (n);
863 }
864
865 static int
ipsec_encap(struct mbuf ** mp,struct secasindex * saidx)866 ipsec_encap(struct mbuf **mp, struct secasindex *saidx)
867 {
868 #ifdef INET6
869 struct ip6_hdr *ip6;
870 #endif
871 struct ip *ip;
872 int setdf;
873 uint8_t itos, proto;
874
875 ip = mtod(*mp, struct ip *);
876 switch (ip->ip_v) {
877 #ifdef INET
878 case IPVERSION:
879 proto = IPPROTO_IPIP;
880 /*
881 * Collect IP_DF state from the inner header
882 * and honor system-wide control of how to handle it.
883 */
884 switch (V_ip4_ipsec_dfbit) {
885 case 0: /* clear in outer header */
886 case 1: /* set in outer header */
887 setdf = V_ip4_ipsec_dfbit;
888 break;
889 default:/* propagate to outer header */
890 setdf = (ip->ip_off & htons(IP_DF)) != 0;
891 }
892 itos = ip->ip_tos;
893 break;
894 #endif
895 #ifdef INET6
896 case (IPV6_VERSION >> 4):
897 proto = IPPROTO_IPV6;
898 ip6 = mtod(*mp, struct ip6_hdr *);
899 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
900 setdf = V_ip4_ipsec_dfbit ? 1: 0;
901 /* scoped address handling */
902 in6_clearscope(&ip6->ip6_src);
903 in6_clearscope(&ip6->ip6_dst);
904 break;
905 #endif
906 default:
907 return (EAFNOSUPPORT);
908 }
909 switch (saidx->dst.sa.sa_family) {
910 #ifdef INET
911 case AF_INET:
912 if (saidx->src.sa.sa_family != AF_INET ||
913 saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
914 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY)
915 return (EINVAL);
916 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT);
917 if (*mp == NULL)
918 return (ENOBUFS);
919 ip = mtod(*mp, struct ip *);
920 ip->ip_v = IPVERSION;
921 ip->ip_hl = sizeof(struct ip) >> 2;
922 ip->ip_p = proto;
923 ip->ip_len = htons((*mp)->m_pkthdr.len);
924 ip->ip_ttl = V_ip_defttl;
925 ip->ip_sum = 0;
926 ip->ip_off = setdf ? htons(IP_DF): 0;
927 ip->ip_src = saidx->src.sin.sin_addr;
928 ip->ip_dst = saidx->dst.sin.sin_addr;
929 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos);
930 ip_fillid(ip);
931 break;
932 #endif /* INET */
933 #ifdef INET6
934 case AF_INET6:
935 if (saidx->src.sa.sa_family != AF_INET6 ||
936 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) ||
937 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr))
938 return (EINVAL);
939 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT);
940 if (*mp == NULL)
941 return (ENOBUFS);
942 ip6 = mtod(*mp, struct ip6_hdr *);
943 ip6->ip6_flow = 0;
944 ip6->ip6_vfc = IPV6_VERSION;
945 ip6->ip6_hlim = V_ip6_defhlim;
946 ip6->ip6_nxt = proto;
947 ip6->ip6_dst = saidx->dst.sin6.sin6_addr;
948 /* For link-local address embed scope zone id */
949 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
950 ip6->ip6_dst.s6_addr16[1] =
951 htons(saidx->dst.sin6.sin6_scope_id & 0xffff);
952 ip6->ip6_src = saidx->src.sin6.sin6_addr;
953 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
954 ip6->ip6_src.s6_addr16[1] =
955 htons(saidx->src.sin6.sin6_scope_id & 0xffff);
956 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6));
957 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos);
958 ip6->ip6_flow |= htonl((uint32_t)proto << 20);
959 break;
960 #endif /* INET6 */
961 default:
962 return (EAFNOSUPPORT);
963 }
964 (*mp)->m_flags &= ~(M_BCAST | M_MCAST);
965 return (0);
966 }
967