1 /* $FreeBSD: src/sys/netinet6/esp_output.c,v 1.1.2.4 2003/05/06 06:46:58 suz Exp $ */
2 /* $DragonFly: src/sys/netinet6/esp_output.c,v 1.4 2003/08/23 11:02:45 rob Exp $ */
3 /* $KAME: esp_output.c,v 1.44 2001/07/26 06:53:15 jinmei Exp $ */
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
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.
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
35 #include "opt_inet6.h"
38 * RFC1827/2406 Encapsulated Security Payload.
41 #include <sys/param.h>
42 #include <sys/systm.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>
50 #include <sys/syslog.h>
53 #include <net/route.h>
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/in_var.h>
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet/icmp6.h>
66 #include <netinet6/ipsec.h>
68 #include <netinet6/ipsec6.h>
70 #include <netinet6/ah.h>
72 #include <netinet6/ah6.h>
74 #include <netinet6/esp.h>
76 #include <netinet6/esp6.h>
78 #include <netproto/key/key.h>
79 #include <netproto/key/keydb.h>
81 #include <net/net_osdep.h>
83 static int esp_output (struct mbuf *, u_char *, struct mbuf *,
84 struct ipsecrequest *, int);
87 * compute ESP header size.
91 struct ipsecrequest *isr;
94 const struct esp_algorithm *algo;
95 const struct ah_algorithm *aalgo;
102 panic("esp_hdrsiz: NULL was passed.");
106 if (isr->saidx.proto != IPPROTO_ESP)
107 panic("unsupported mode passed to esp_hdrsiz");
111 if (sav->state != SADB_SASTATE_MATURE
112 && sav->state != SADB_SASTATE_DYING)
115 /* we need transport mode ESP. */
116 algo = esp_algorithm_lookup(sav->alg_enc);
125 * right now we don't calcurate the padding size. simply
126 * treat the padding size as constant, for simplicity.
128 * XXX variable size padding support
130 if (sav->flags & SADB_X_EXT_OLD) {
132 hdrsiz = sizeof(struct esp) + ivlen + 9;
135 aalgo = ah_algorithm_lookup(sav->alg_auth);
136 if (aalgo && sav->replay && sav->key_auth)
137 authlen = (aalgo->sumsiz)(sav);
140 hdrsiz = sizeof(struct newesp) + ivlen + 9 + authlen;
148 * sizeof(struct newesp) > sizeof(struct esp).
149 * esp_max_ivlen() = max ivlen for CBC mode
150 * 9 = (maximum padding length without random padding length)
151 * + (Pad Length field) + (Next Header field).
152 * 16 = maximum ICV we support.
154 return sizeof(struct newesp) + esp_max_ivlen() + 9 + 16;
158 * Modify the packet so that the payload is encrypted.
159 * The mbuf (m) must start with IPv4 or IPv6 header.
160 * On failure, free the given mbuf and return NULL.
165 * IP ......... payload
166 * during the encryption:
167 * m nexthdrp mprev md
169 * IP ............... esp iv payload pad padlen nxthdr
170 * <--><-><------><--------------->
171 * esplen plen extendsiz
175 * <-----------------> espoff
178 esp_output(m, nexthdrp, md, isr, af)
182 struct ipsecrequest *isr;
188 struct esptail *esptail;
189 struct secasvar *sav = isr->sav;
190 const struct esp_algorithm *algo;
193 size_t plen; /* payload length to be encrypted */
199 struct ipsecstat *stat;
215 ipseclog((LOG_ERR, "esp_output: unsupported af %d\n", af));
216 return 0; /* no change at all */
219 /* some sanity check */
220 if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
227 ip = mtod(m, struct ip *);
228 ipseclog((LOG_DEBUG, "esp4_output: internal error: "
229 "sav->replay is null: %x->%x, SPI=%u\n",
230 (u_int32_t)ntohl(ip->ip_src.s_addr),
231 (u_int32_t)ntohl(ip->ip_dst.s_addr),
232 (u_int32_t)ntohl(sav->spi)));
233 ipsecstat.out_inval++;
239 ipseclog((LOG_DEBUG, "esp6_output: internal error: "
240 "sav->replay is null: SPI=%u\n",
241 (u_int32_t)ntohl(sav->spi)));
242 ipsec6stat.out_inval++;
246 panic("esp_output: should not reach here");
252 algo = esp_algorithm_lookup(sav->alg_enc);
254 ipseclog((LOG_ERR, "esp_output: unsupported algorithm: "
255 "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
263 panic("invalid ivlen");
269 * XXX inserts ESP header right after IPv4 header. should
270 * chase the header chain.
271 * XXX sequential number
274 struct ip *ip = NULL;
277 struct ip6_hdr *ip6 = NULL;
279 size_t esplen; /* sizeof(struct esp/newesp) */
280 size_t esphlen; /* sizeof(struct esp/newesp) + ivlen */
281 size_t hlen = 0; /* ip header len */
283 if (sav->flags & SADB_X_EXT_OLD) {
285 esplen = sizeof(struct esp);
288 if (sav->flags & SADB_X_EXT_DERIV)
289 esplen = sizeof(struct esp);
291 esplen = sizeof(struct newesp);
293 esphlen = esplen + ivlen;
295 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
297 if (mprev == NULL || mprev->m_next != md) {
298 ipseclog((LOG_DEBUG, "esp%d_output: md is not in chain\n",
305 for (n = md; n; n = n->m_next)
311 ip = mtod(m, struct ip *);
313 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
315 hlen = ip->ip_hl << 2;
321 ip6 = mtod(m, struct ip6_hdr *);
327 /* make the packet over-writable */
328 mprev->m_next = NULL;
329 if ((md = ipsec_copypkt(md)) == NULL) {
336 espoff = m->m_pkthdr.len - plen;
339 * grow the mbuf to accomodate ESP header.
340 * before: IP ... payload
341 * after: IP ... ESP IV payload
343 if (M_LEADINGSPACE(md) < esphlen || (md->m_flags & M_EXT) != 0) {
344 MGET(n, M_DONTWAIT, MT_DATA);
353 m->m_pkthdr.len += esphlen;
354 esp = mtod(n, struct esp *);
356 md->m_len += esphlen;
357 md->m_data -= esphlen;
358 m->m_pkthdr.len += esphlen;
359 esp = mtod(md, struct esp *);
363 *nexthdrp = IPPROTO_ESP;
367 if (esphlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
368 ip->ip_len = htons(ntohs(ip->ip_len) + esphlen);
371 "IPv4 ESP output: size exceeds limit\n"));
372 ipsecstat.out_inval++;
381 /* total packet length will be computed in ip6_output() */
387 /* initialize esp header. */
389 if ((sav->flags & SADB_X_EXT_OLD) == 0) {
391 nesp = (struct newesp *)esp;
392 if (sav->replay->count == ~0) {
393 if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
394 /* XXX Is it noisy ? */
395 ipseclog((LOG_WARNING,
396 "replay counter overflowed. %s\n",
397 ipsec_logsastr(sav)));
403 sav->replay->count++;
405 * XXX sequence number must not be cycled, if the SA is
406 * installed by IKE daemon.
408 nesp->esp_seq = htonl(sav->replay->count);
413 * find the last mbuf. make some room for ESP trailer.
416 struct ip *ip = NULL;
424 padbound = algo->padbound;
427 /* ESP packet, including nxthdr field, must be length of 4n */
431 extendsiz = padbound - (plen % padbound);
433 extendsiz = padbound + 1;
439 randpadmax = ip4_esp_randpad;
444 randpadmax = ip6_esp_randpad;
451 if (randpadmax < 0 || plen + extendsiz >= randpadmax)
457 randpadmax = (randpadmax / padbound) * padbound;
458 n = (randpadmax - plen + extendsiz) / padbound;
461 n = (random() % n) * padbound;
466 * make sure we do not pad too much.
467 * MLEN limitation comes from the trailer attachment
469 * 256 limitation comes from sequential padding.
470 * also, the 1-octet length field in ESP trailer imposes
471 * limitation (but is less strict than sequential padding
472 * as length field do not count the last 2 octets).
474 if (extendsiz + n <= MLEN && extendsiz + n < 256)
479 if (extendsiz > MLEN || extendsiz >= 256)
480 panic("extendsiz too big in esp_output");
488 * if M_EXT, the external mbuf data may be shared among
489 * two consequtive TCP packets, and it may be unsafe to use the
492 if (!(n->m_flags & M_EXT) && extendsiz < M_TRAILINGSPACE(n)) {
493 extend = mtod(n, u_char *) + n->m_len;
494 n->m_len += extendsiz;
495 m->m_pkthdr.len += extendsiz;
499 MGET(nn, M_DONTWAIT, MT_DATA);
501 ipseclog((LOG_DEBUG, "esp%d_output: can't alloc mbuf",
507 extend = mtod(nn, u_char *);
508 nn->m_len = extendsiz;
512 m->m_pkthdr.len += extendsiz;
514 switch (sav->flags & SADB_X_EXT_PMASK) {
515 case SADB_X_EXT_PRAND:
516 key_randomfill(extend, extendsiz);
518 case SADB_X_EXT_PZERO:
519 bzero(extend, extendsiz);
521 case SADB_X_EXT_PSEQ:
522 for (i = 0; i < extendsiz; i++)
523 extend[i] = (i + 1) & 0xff;
527 /* initialize esp trailer. */
528 esptail = (struct esptail *)
529 (mtod(n, u_int8_t *) + n->m_len - sizeof(struct esptail));
530 esptail->esp_nxt = nxt;
531 esptail->esp_padlen = extendsiz - 2;
533 /* modify IP header (for ESP header part only) */
537 ip = mtod(m, struct ip *);
538 if (extendsiz < (IP_MAXPACKET - ntohs(ip->ip_len)))
539 ip->ip_len = htons(ntohs(ip->ip_len) + extendsiz);
542 "IPv4 ESP output: size exceeds limit\n"));
543 ipsecstat.out_inval++;
552 /* total packet length will be computed in ip6_output() */
559 * pre-compute and cache intermediate key
561 error = esp_schedule(algo, sav);
569 * encrypt the packet, based on security association
570 * and the algorithm specified.
573 panic("internal error: no encrypt function");
574 if ((*algo->encrypt)(m, espoff, plen + extendsiz, sav, algo, ivlen)) {
575 /* m is already freed */
576 ipseclog((LOG_ERR, "packet encryption failure\n"));
583 * calculate ICV if required.
589 if (sav->key_auth == SADB_AALG_NONE)
593 const struct ah_algorithm *aalgo;
594 u_char authbuf[AH_MAXSUMSIZE];
602 aalgo = ah_algorithm_lookup(sav->alg_auth);
605 siz = ((aalgo->sumsiz)(sav) + 3) & ~(4 - 1);
606 if (AH_MAXSUMSIZE < siz)
607 panic("assertion failed for AH_MAXSUMSIZE");
609 if (esp_auth(m, espoff, m->m_pkthdr.len - espoff, sav, authbuf)) {
610 ipseclog((LOG_ERR, "ESP checksum generation failure\n"));
621 if (!(n->m_flags & M_EXT) && siz < M_TRAILINGSPACE(n)) { /* XXX */
623 m->m_pkthdr.len += siz;
624 p = mtod(n, u_char *) + n->m_len - siz;
628 MGET(nn, M_DONTWAIT, MT_DATA);
630 ipseclog((LOG_DEBUG, "can't alloc mbuf in esp%d_output",
640 m->m_pkthdr.len += siz;
641 p = mtod(nn, u_char *);
643 bcopy(authbuf, p, siz);
645 /* modify IP header (for ESP header part only) */
649 ip = mtod(m, struct ip *);
650 if (siz < (IP_MAXPACKET - ntohs(ip->ip_len)))
651 ip->ip_len = htons(ntohs(ip->ip_len) + siz);
654 "IPv4 ESP output: size exceeds limit\n"));
655 ipsecstat.out_inval++;
664 /* total packet length will be computed in ip6_output() */
673 "NULL mbuf after encryption in esp%d_output", afnumber));
676 stat->out_esphist[sav->alg_enc]++;
677 key_sa_recordxfer(sav, m);
684 panic("something bad in esp_output");
692 struct ipsecrequest *isr;
695 if (m->m_len < sizeof(struct ip)) {
696 ipseclog((LOG_DEBUG, "esp4_output: first mbuf too short\n"));
700 ip = mtod(m, struct ip *);
701 /* XXX assumes that m->m_next points to payload */
702 return esp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
708 esp6_output(m, nexthdrp, md, isr)
712 struct ipsecrequest *isr;
714 if (m->m_len < sizeof(struct ip6_hdr)) {
715 ipseclog((LOG_DEBUG, "esp6_output: first mbuf too short\n"));
719 return esp_output(m, nexthdrp, md, isr, AF_INET6);