Change mbug allocation flags from M_ to MB_ to avoid confusion with malloc
[dragonfly.git] / sys / netinet6 / esp_output.c
CommitLineData
984263bc 1/* $FreeBSD: src/sys/netinet6/esp_output.c,v 1.1.2.4 2003/05/06 06:46:58 suz Exp $ */
74f1caca 2/* $DragonFly: src/sys/netinet6/esp_output.c,v 1.6 2004/06/02 14:43:01 eirikn Exp $ */
984263bc
MD
3/* $KAME: esp_output.c,v 1.44 2001/07/26 06:53:15 jinmei Exp $ */
4
5/*
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "opt_inet.h"
35#include "opt_inet6.h"
36
37/*
38 * RFC1827/2406 Encapsulated Security Payload.
39 */
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/mbuf.h>
44#include <sys/domain.h>
45#include <sys/protosw.h>
46#include <sys/socket.h>
47#include <sys/socketvar.h>
48#include <sys/errno.h>
49#include <sys/time.h>
50#include <sys/syslog.h>
51
52#include <net/if.h>
53#include <net/route.h>
54
55#include <netinet/in.h>
56#include <netinet/in_systm.h>
57#include <netinet/ip.h>
58#include <netinet/in_var.h>
59
60#ifdef INET6
61#include <netinet/ip6.h>
62#include <netinet6/ip6_var.h>
63#include <netinet/icmp6.h>
64#endif
65
66#include <netinet6/ipsec.h>
67#ifdef INET6
68#include <netinet6/ipsec6.h>
69#endif
70#include <netinet6/ah.h>
71#ifdef INET6
72#include <netinet6/ah6.h>
73#endif
74#include <netinet6/esp.h>
75#ifdef INET6
76#include <netinet6/esp6.h>
77#endif
d2438d69
MD
78#include <netproto/key/key.h>
79#include <netproto/key/keydb.h>
984263bc
MD
80
81#include <net/net_osdep.h>
82
56d702cc
RG
83static int esp_output (struct mbuf *, u_char *, struct mbuf *,
84 struct ipsecrequest *, int);
984263bc
MD
85
86/*
87 * compute ESP header size.
88 */
89size_t
122ebd49 90esp_hdrsiz(struct ipsecrequest *isr)
984263bc
MD
91{
92 struct secasvar *sav;
93 const struct esp_algorithm *algo;
94 const struct ah_algorithm *aalgo;
95 size_t ivlen;
96 size_t authlen;
97 size_t hdrsiz;
98
99 /* sanity check */
100 if (isr == NULL)
101 panic("esp_hdrsiz: NULL was passed.");
102
103 sav = isr->sav;
104
105 if (isr->saidx.proto != IPPROTO_ESP)
106 panic("unsupported mode passed to esp_hdrsiz");
107
108 if (sav == NULL)
109 goto estimate;
110 if (sav->state != SADB_SASTATE_MATURE
111 && sav->state != SADB_SASTATE_DYING)
112 goto estimate;
113
114 /* we need transport mode ESP. */
115 algo = esp_algorithm_lookup(sav->alg_enc);
116 if (!algo)
117 goto estimate;
118 ivlen = sav->ivlen;
119 if (ivlen < 0)
120 goto estimate;
121
122 /*
123 * XXX
124 * right now we don't calcurate the padding size. simply
125 * treat the padding size as constant, for simplicity.
126 *
127 * XXX variable size padding support
128 */
129 if (sav->flags & SADB_X_EXT_OLD) {
130 /* RFC 1827 */
131 hdrsiz = sizeof(struct esp) + ivlen + 9;
132 } else {
133 /* RFC 2406 */
134 aalgo = ah_algorithm_lookup(sav->alg_auth);
135 if (aalgo && sav->replay && sav->key_auth)
136 authlen = (aalgo->sumsiz)(sav);
137 else
138 authlen = 0;
139 hdrsiz = sizeof(struct newesp) + ivlen + 9 + authlen;
140 }
141
142 return hdrsiz;
143
144 estimate:
145 /*
146 * ASSUMING:
147 * sizeof(struct newesp) > sizeof(struct esp).
148 * esp_max_ivlen() = max ivlen for CBC mode
149 * 9 = (maximum padding length without random padding length)
150 * + (Pad Length field) + (Next Header field).
151 * 16 = maximum ICV we support.
152 */
153 return sizeof(struct newesp) + esp_max_ivlen() + 9 + 16;
154}
155
156/*
157 * Modify the packet so that the payload is encrypted.
158 * The mbuf (m) must start with IPv4 or IPv6 header.
159 * On failure, free the given mbuf and return NULL.
160 *
161 * on invocation:
162 * m nexthdrp md
163 * v v v
164 * IP ......... payload
165 * during the encryption:
166 * m nexthdrp mprev md
167 * v v v v
168 * IP ............... esp iv payload pad padlen nxthdr
169 * <--><-><------><--------------->
170 * esplen plen extendsiz
171 * ivlen
172 * <-----> esphlen
173 * <-> hlen
174 * <-----------------> espoff
175 */
176static int
122ebd49
CP
177esp_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
178 struct ipsecrequest *isr, int af)
984263bc
MD
179{
180 struct mbuf *n;
181 struct mbuf *mprev;
182 struct esp *esp;
183 struct esptail *esptail;
184 struct secasvar *sav = isr->sav;
185 const struct esp_algorithm *algo;
186 u_int32_t spi;
187 u_int8_t nxt = 0;
188 size_t plen; /* payload length to be encrypted */
189 size_t espoff;
190 int ivlen;
191 int afnumber;
192 size_t extendsiz;
193 int error = 0;
194 struct ipsecstat *stat;
195
196 switch (af) {
197#ifdef INET
198 case AF_INET:
199 afnumber = 4;
200 stat = &ipsecstat;
201 break;
202#endif
203#ifdef INET6
204 case AF_INET6:
205 afnumber = 6;
206 stat = &ipsec6stat;
207 break;
208#endif
209 default:
210 ipseclog((LOG_ERR, "esp_output: unsupported af %d\n", af));
211 return 0; /* no change at all */
212 }
213
214 /* some sanity check */
215 if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
216 switch (af) {
217#ifdef INET
218 case AF_INET:
219 {
220 struct ip *ip;
221
222 ip = mtod(m, struct ip *);
223 ipseclog((LOG_DEBUG, "esp4_output: internal error: "
224 "sav->replay is null: %x->%x, SPI=%u\n",
225 (u_int32_t)ntohl(ip->ip_src.s_addr),
226 (u_int32_t)ntohl(ip->ip_dst.s_addr),
227 (u_int32_t)ntohl(sav->spi)));
228 ipsecstat.out_inval++;
229 break;
230 }
231#endif /* INET */
232#ifdef INET6
233 case AF_INET6:
234 ipseclog((LOG_DEBUG, "esp6_output: internal error: "
235 "sav->replay is null: SPI=%u\n",
236 (u_int32_t)ntohl(sav->spi)));
237 ipsec6stat.out_inval++;
238 break;
239#endif /* INET6 */
240 default:
241 panic("esp_output: should not reach here");
242 }
243 m_freem(m);
244 return EINVAL;
245 }
246
247 algo = esp_algorithm_lookup(sav->alg_enc);
248 if (!algo) {
249 ipseclog((LOG_ERR, "esp_output: unsupported algorithm: "
250 "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
251 m_freem(m);
252 return EINVAL;
253 }
254 spi = sav->spi;
255 ivlen = sav->ivlen;
256 /* should be okey */
257 if (ivlen < 0) {
258 panic("invalid ivlen");
259 }
260
261 {
262 /*
263 * insert ESP header.
264 * XXX inserts ESP header right after IPv4 header. should
265 * chase the header chain.
266 * XXX sequential number
267 */
268#ifdef INET
269 struct ip *ip = NULL;
270#endif
271#ifdef INET6
272 struct ip6_hdr *ip6 = NULL;
273#endif
274 size_t esplen; /* sizeof(struct esp/newesp) */
275 size_t esphlen; /* sizeof(struct esp/newesp) + ivlen */
276 size_t hlen = 0; /* ip header len */
277
278 if (sav->flags & SADB_X_EXT_OLD) {
279 /* RFC 1827 */
280 esplen = sizeof(struct esp);
281 } else {
282 /* RFC 2406 */
283 if (sav->flags & SADB_X_EXT_DERIV)
284 esplen = sizeof(struct esp);
285 else
286 esplen = sizeof(struct newesp);
287 }
288 esphlen = esplen + ivlen;
289
290 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
291 ;
292 if (mprev == NULL || mprev->m_next != md) {
293 ipseclog((LOG_DEBUG, "esp%d_output: md is not in chain\n",
294 afnumber));
295 m_freem(m);
296 return EINVAL;
297 }
298
299 plen = 0;
300 for (n = md; n; n = n->m_next)
301 plen += n->m_len;
302
303 switch (af) {
304#ifdef INET
305 case AF_INET:
306 ip = mtod(m, struct ip *);
307#ifdef _IP_VHL
308 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
309#else
310 hlen = ip->ip_hl << 2;
311#endif
312 break;
313#endif
314#ifdef INET6
315 case AF_INET6:
316 ip6 = mtod(m, struct ip6_hdr *);
317 hlen = sizeof(*ip6);
318 break;
319#endif
320 }
321
322 /* make the packet over-writable */
323 mprev->m_next = NULL;
324 if ((md = ipsec_copypkt(md)) == NULL) {
325 m_freem(m);
326 error = ENOBUFS;
327 goto fail;
328 }
329 mprev->m_next = md;
330
331 espoff = m->m_pkthdr.len - plen;
332
333 /*
334 * grow the mbuf to accomodate ESP header.
335 * before: IP ... payload
336 * after: IP ... ESP IV payload
337 */
338 if (M_LEADINGSPACE(md) < esphlen || (md->m_flags & M_EXT) != 0) {
74f1caca 339 MGET(n, MB_DONTWAIT, MT_DATA);
984263bc
MD
340 if (!n) {
341 m_freem(m);
342 error = ENOBUFS;
343 goto fail;
344 }
345 n->m_len = esphlen;
346 mprev->m_next = n;
347 n->m_next = md;
348 m->m_pkthdr.len += esphlen;
349 esp = mtod(n, struct esp *);
350 } else {
351 md->m_len += esphlen;
352 md->m_data -= esphlen;
353 m->m_pkthdr.len += esphlen;
354 esp = mtod(md, struct esp *);
355 }
356
357 nxt = *nexthdrp;
358 *nexthdrp = IPPROTO_ESP;
359 switch (af) {
360#ifdef INET
361 case AF_INET:
362 if (esphlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
363 ip->ip_len = htons(ntohs(ip->ip_len) + esphlen);
364 else {
365 ipseclog((LOG_ERR,
366 "IPv4 ESP output: size exceeds limit\n"));
367 ipsecstat.out_inval++;
368 m_freem(m);
369 error = EMSGSIZE;
370 goto fail;
371 }
372 break;
373#endif
374#ifdef INET6
375 case AF_INET6:
376 /* total packet length will be computed in ip6_output() */
377 break;
378#endif
379 }
380 }
381
382 /* initialize esp header. */
383 esp->esp_spi = spi;
384 if ((sav->flags & SADB_X_EXT_OLD) == 0) {
385 struct newesp *nesp;
386 nesp = (struct newesp *)esp;
387 if (sav->replay->count == ~0) {
388 if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
389 /* XXX Is it noisy ? */
390 ipseclog((LOG_WARNING,
391 "replay counter overflowed. %s\n",
392 ipsec_logsastr(sav)));
393 stat->out_inval++;
394 m_freem(m);
395 return EINVAL;
396 }
397 }
398 sav->replay->count++;
399 /*
400 * XXX sequence number must not be cycled, if the SA is
401 * installed by IKE daemon.
402 */
403 nesp->esp_seq = htonl(sav->replay->count);
404 }
405
406 {
407 /*
408 * find the last mbuf. make some room for ESP trailer.
409 */
410#ifdef INET
411 struct ip *ip = NULL;
412#endif
413 size_t padbound;
414 u_char *extend;
415 int i;
416 int randpadmax;
417
418 if (algo->padbound)
419 padbound = algo->padbound;
420 else
421 padbound = 4;
422 /* ESP packet, including nxthdr field, must be length of 4n */
423 if (padbound < 4)
424 padbound = 4;
425
426 extendsiz = padbound - (plen % padbound);
427 if (extendsiz == 1)
428 extendsiz = padbound + 1;
429
430 /* random padding */
431 switch (af) {
432#ifdef INET
433 case AF_INET:
434 randpadmax = ip4_esp_randpad;
435 break;
436#endif
437#ifdef INET6
438 case AF_INET6:
439 randpadmax = ip6_esp_randpad;
440 break;
441#endif
442 default:
443 randpadmax = -1;
444 break;
445 }
446 if (randpadmax < 0 || plen + extendsiz >= randpadmax)
447 ;
448 else {
449 int n;
450
451 /* round */
452 randpadmax = (randpadmax / padbound) * padbound;
453 n = (randpadmax - plen + extendsiz) / padbound;
454
455 if (n > 0)
456 n = (random() % n) * padbound;
457 else
458 n = 0;
459
460 /*
461 * make sure we do not pad too much.
462 * MLEN limitation comes from the trailer attachment
463 * code below.
464 * 256 limitation comes from sequential padding.
465 * also, the 1-octet length field in ESP trailer imposes
466 * limitation (but is less strict than sequential padding
467 * as length field do not count the last 2 octets).
468 */
469 if (extendsiz + n <= MLEN && extendsiz + n < 256)
470 extendsiz += n;
471 }
472
473#ifdef DIAGNOSTIC
474 if (extendsiz > MLEN || extendsiz >= 256)
475 panic("extendsiz too big in esp_output");
476#endif
477
478 n = m;
479 while (n->m_next)
480 n = n->m_next;
481
482 /*
483 * if M_EXT, the external mbuf data may be shared among
484 * two consequtive TCP packets, and it may be unsafe to use the
485 * trailing space.
486 */
487 if (!(n->m_flags & M_EXT) && extendsiz < M_TRAILINGSPACE(n)) {
488 extend = mtod(n, u_char *) + n->m_len;
489 n->m_len += extendsiz;
490 m->m_pkthdr.len += extendsiz;
491 } else {
492 struct mbuf *nn;
493
74f1caca 494 MGET(nn, MB_DONTWAIT, MT_DATA);
984263bc
MD
495 if (!nn) {
496 ipseclog((LOG_DEBUG, "esp%d_output: can't alloc mbuf",
497 afnumber));
498 m_freem(m);
499 error = ENOBUFS;
500 goto fail;
501 }
502 extend = mtod(nn, u_char *);
503 nn->m_len = extendsiz;
504 nn->m_next = NULL;
505 n->m_next = nn;
506 n = nn;
507 m->m_pkthdr.len += extendsiz;
508 }
509 switch (sav->flags & SADB_X_EXT_PMASK) {
510 case SADB_X_EXT_PRAND:
511 key_randomfill(extend, extendsiz);
512 break;
513 case SADB_X_EXT_PZERO:
514 bzero(extend, extendsiz);
515 break;
516 case SADB_X_EXT_PSEQ:
517 for (i = 0; i < extendsiz; i++)
518 extend[i] = (i + 1) & 0xff;
519 break;
520 }
521
522 /* initialize esp trailer. */
523 esptail = (struct esptail *)
524 (mtod(n, u_int8_t *) + n->m_len - sizeof(struct esptail));
525 esptail->esp_nxt = nxt;
526 esptail->esp_padlen = extendsiz - 2;
527
528 /* modify IP header (for ESP header part only) */
529 switch (af) {
530#ifdef INET
531 case AF_INET:
532 ip = mtod(m, struct ip *);
533 if (extendsiz < (IP_MAXPACKET - ntohs(ip->ip_len)))
534 ip->ip_len = htons(ntohs(ip->ip_len) + extendsiz);
535 else {
536 ipseclog((LOG_ERR,
537 "IPv4 ESP output: size exceeds limit\n"));
538 ipsecstat.out_inval++;
539 m_freem(m);
540 error = EMSGSIZE;
541 goto fail;
542 }
543 break;
544#endif
545#ifdef INET6
546 case AF_INET6:
547 /* total packet length will be computed in ip6_output() */
548 break;
549#endif
550 }
551 }
552
553 /*
554 * pre-compute and cache intermediate key
555 */
556 error = esp_schedule(algo, sav);
557 if (error) {
558 m_freem(m);
559 stat->out_inval++;
560 goto fail;
561 }
562
563 /*
564 * encrypt the packet, based on security association
565 * and the algorithm specified.
566 */
567 if (!algo->encrypt)
568 panic("internal error: no encrypt function");
569 if ((*algo->encrypt)(m, espoff, plen + extendsiz, sav, algo, ivlen)) {
570 /* m is already freed */
571 ipseclog((LOG_ERR, "packet encryption failure\n"));
572 stat->out_inval++;
573 error = EINVAL;
574 goto fail;
575 }
576
577 /*
578 * calculate ICV if required.
579 */
580 if (!sav->replay)
581 goto noantireplay;
582 if (!sav->key_auth)
583 goto noantireplay;
584 if (sav->key_auth == SADB_AALG_NONE)
585 goto noantireplay;
586
587 {
588 const struct ah_algorithm *aalgo;
589 u_char authbuf[AH_MAXSUMSIZE];
590 struct mbuf *n;
591 u_char *p;
592 size_t siz;
593#ifdef INET
594 struct ip *ip;
595#endif
596
597 aalgo = ah_algorithm_lookup(sav->alg_auth);
598 if (!aalgo)
599 goto noantireplay;
600 siz = ((aalgo->sumsiz)(sav) + 3) & ~(4 - 1);
601 if (AH_MAXSUMSIZE < siz)
602 panic("assertion failed for AH_MAXSUMSIZE");
603
604 if (esp_auth(m, espoff, m->m_pkthdr.len - espoff, sav, authbuf)) {
605 ipseclog((LOG_ERR, "ESP checksum generation failure\n"));
606 m_freem(m);
607 error = EINVAL;
608 stat->out_inval++;
609 goto fail;
610 }
611
612 n = m;
613 while (n->m_next)
614 n = n->m_next;
615
616 if (!(n->m_flags & M_EXT) && siz < M_TRAILINGSPACE(n)) { /* XXX */
617 n->m_len += siz;
618 m->m_pkthdr.len += siz;
619 p = mtod(n, u_char *) + n->m_len - siz;
620 } else {
621 struct mbuf *nn;
622
74f1caca 623 MGET(nn, MB_DONTWAIT, MT_DATA);
984263bc
MD
624 if (!nn) {
625 ipseclog((LOG_DEBUG, "can't alloc mbuf in esp%d_output",
626 afnumber));
627 m_freem(m);
628 error = ENOBUFS;
629 goto fail;
630 }
631 nn->m_len = siz;
632 nn->m_next = NULL;
633 n->m_next = nn;
634 n = nn;
635 m->m_pkthdr.len += siz;
636 p = mtod(nn, u_char *);
637 }
638 bcopy(authbuf, p, siz);
639
640 /* modify IP header (for ESP header part only) */
641 switch (af) {
642#ifdef INET
643 case AF_INET:
644 ip = mtod(m, struct ip *);
645 if (siz < (IP_MAXPACKET - ntohs(ip->ip_len)))
646 ip->ip_len = htons(ntohs(ip->ip_len) + siz);
647 else {
648 ipseclog((LOG_ERR,
649 "IPv4 ESP output: size exceeds limit\n"));
650 ipsecstat.out_inval++;
651 m_freem(m);
652 error = EMSGSIZE;
653 goto fail;
654 }
655 break;
656#endif
657#ifdef INET6
658 case AF_INET6:
659 /* total packet length will be computed in ip6_output() */
660 break;
661#endif
662 }
663 }
664
665noantireplay:
666 if (!m) {
667 ipseclog((LOG_ERR,
668 "NULL mbuf after encryption in esp%d_output", afnumber));
669 } else
670 stat->out_success++;
671 stat->out_esphist[sav->alg_enc]++;
672 key_sa_recordxfer(sav, m);
673 return 0;
674
675fail:
676#if 1
677 return error;
678#else
679 panic("something bad in esp_output");
680#endif
681}
682
683#ifdef INET
684int
122ebd49 685esp4_output(struct mbuf *m, struct ipsecrequest *isr)
984263bc
MD
686{
687 struct ip *ip;
688 if (m->m_len < sizeof(struct ip)) {
689 ipseclog((LOG_DEBUG, "esp4_output: first mbuf too short\n"));
690 m_freem(m);
691 return 0;
692 }
693 ip = mtod(m, struct ip *);
694 /* XXX assumes that m->m_next points to payload */
695 return esp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
696}
697#endif /* INET */
698
699#ifdef INET6
700int
122ebd49
CP
701esp6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
702 struct ipsecrequest *isr)
984263bc
MD
703{
704 if (m->m_len < sizeof(struct ip6_hdr)) {
705 ipseclog((LOG_DEBUG, "esp6_output: first mbuf too short\n"));
706 m_freem(m);
707 return 0;
708 }
709 return esp_output(m, nexthdrp, md, isr, AF_INET6);
710}
711#endif /* INET6 */