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 1.8 2006/09/03 18:52:29 dillon 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.
90 esp_hdrsiz(struct ipsecrequest *isr)
93 const struct esp_algorithm *algo;
94 const struct ah_algorithm *aalgo;
101 panic("esp_hdrsiz: NULL was passed.");
105 if (isr->saidx.proto != IPPROTO_ESP)
106 panic("unsupported mode passed to esp_hdrsiz");
110 if (sav->state != SADB_SASTATE_MATURE
111 && sav->state != SADB_SASTATE_DYING)
114 /* we need transport mode ESP. */
115 algo = esp_algorithm_lookup(sav->alg_enc);
124 * right now we don't calcurate the padding size. simply
125 * treat the padding size as constant, for simplicity.
127 * XXX variable size padding support
129 if (sav->flags & SADB_X_EXT_OLD) {
131 hdrsiz = sizeof(struct esp) + ivlen + 9;
134 aalgo = ah_algorithm_lookup(sav->alg_auth);
135 if (aalgo && sav->replay && sav->key_auth)
136 authlen = (aalgo->sumsiz)(sav);
139 hdrsiz = sizeof(struct newesp) + ivlen + 9 + authlen;
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.
153 return sizeof(struct newesp) + esp_max_ivlen() + 9 + 16;
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.
164 * IP ......... payload
165 * during the encryption:
166 * m nexthdrp mprev md
168 * IP ............... esp iv payload pad padlen nxthdr
169 * <--><-><------><--------------->
170 * esplen plen extendsiz
174 * <-----------------> espoff
177 esp_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
178 struct ipsecrequest *isr, int af)
183 struct esptail *esptail;
184 struct secasvar *sav = isr->sav;
185 const struct esp_algorithm *algo;
188 size_t plen; /* payload length to be encrypted */
194 struct ipsecstat *stat;
210 ipseclog((LOG_ERR, "esp_output: unsupported af %d\n", af));
211 return 0; /* no change at all */
214 /* some sanity check */
215 if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
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++;
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++;
241 panic("esp_output: should not reach here");
247 algo = esp_algorithm_lookup(sav->alg_enc);
249 ipseclog((LOG_ERR, "esp_output: unsupported algorithm: "
250 "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
258 panic("invalid ivlen");
264 * XXX inserts ESP header right after IPv4 header. should
265 * chase the header chain.
266 * XXX sequential number
269 struct ip *ip = NULL;
272 struct ip6_hdr *ip6 = NULL;
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 */
278 if (sav->flags & SADB_X_EXT_OLD) {
280 esplen = sizeof(struct esp);
283 if (sav->flags & SADB_X_EXT_DERIV)
284 esplen = sizeof(struct esp);
286 esplen = sizeof(struct newesp);
288 esphlen = esplen + ivlen;
290 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
292 if (mprev == NULL || mprev->m_next != md) {
293 ipseclog((LOG_DEBUG, "esp%d_output: md is not in chain\n",
300 for (n = md; n; n = n->m_next)
306 ip = mtod(m, struct ip *);
308 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
310 hlen = ip->ip_hl << 2;
316 ip6 = mtod(m, struct ip6_hdr *);
322 /* make the packet over-writable */
323 mprev->m_next = NULL;
324 if ((md = ipsec_copypkt(md)) == NULL) {
331 espoff = m->m_pkthdr.len - plen;
334 * grow the mbuf to accomodate ESP header.
335 * before: IP ... payload
336 * after: IP ... ESP IV payload
338 if (M_LEADINGSPACE(md) < esphlen || (md->m_flags & M_EXT) != 0) {
339 MGET(n, MB_DONTWAIT, MT_DATA);
348 m->m_pkthdr.len += esphlen;
349 esp = mtod(n, struct esp *);
351 md->m_len += esphlen;
352 md->m_data -= esphlen;
353 m->m_pkthdr.len += esphlen;
354 esp = mtod(md, struct esp *);
358 *nexthdrp = IPPROTO_ESP;
362 if (esphlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
363 ip->ip_len = htons(ntohs(ip->ip_len) + esphlen);
366 "IPv4 ESP output: size exceeds limit\n"));
367 ipsecstat.out_inval++;
376 /* total packet length will be computed in ip6_output() */
382 /* initialize esp header. */
384 if ((sav->flags & SADB_X_EXT_OLD) == 0) {
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)));
398 sav->replay->count++;
400 * XXX sequence number must not be cycled, if the SA is
401 * installed by IKE daemon.
403 nesp->esp_seq = htonl(sav->replay->count & 0xffffffff);
408 * find the last mbuf. make some room for ESP trailer.
411 struct ip *ip = NULL;
419 padbound = algo->padbound;
422 /* ESP packet, including nxthdr field, must be length of 4n */
426 extendsiz = padbound - (plen % padbound);
428 extendsiz = padbound + 1;
434 randpadmax = ip4_esp_randpad;
439 randpadmax = ip6_esp_randpad;
446 if (randpadmax < 0 || plen + extendsiz >= randpadmax)
452 randpadmax = (randpadmax / padbound) * padbound;
453 n = (randpadmax - plen + extendsiz) / padbound;
456 n = (krandom() % n) * padbound;
461 * make sure we do not pad too much.
462 * MLEN limitation comes from the trailer attachment
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).
469 if (extendsiz + n <= MLEN && extendsiz + n < 256)
474 if (extendsiz > MLEN || extendsiz >= 256)
475 panic("extendsiz too big in esp_output");
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
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;
494 MGET(nn, MB_DONTWAIT, MT_DATA);
496 ipseclog((LOG_DEBUG, "esp%d_output: can't alloc mbuf",
502 extend = mtod(nn, u_char *);
503 nn->m_len = extendsiz;
507 m->m_pkthdr.len += extendsiz;
509 switch (sav->flags & SADB_X_EXT_PMASK) {
510 case SADB_X_EXT_PRAND:
511 key_randomfill(extend, extendsiz);
513 case SADB_X_EXT_PZERO:
514 bzero(extend, extendsiz);
516 case SADB_X_EXT_PSEQ:
517 for (i = 0; i < extendsiz; i++)
518 extend[i] = (i + 1) & 0xff;
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;
528 /* modify IP header (for ESP header part only) */
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);
537 "IPv4 ESP output: size exceeds limit\n"));
538 ipsecstat.out_inval++;
547 /* total packet length will be computed in ip6_output() */
554 * pre-compute and cache intermediate key
556 error = esp_schedule(algo, sav);
564 * encrypt the packet, based on security association
565 * and the algorithm specified.
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"));
578 * calculate ICV if required.
584 if (sav->alg_auth == SADB_AALG_NONE)
588 const struct ah_algorithm *aalgo;
589 u_char authbuf[AH_MAXSUMSIZE];
597 aalgo = ah_algorithm_lookup(sav->alg_auth);
600 siz = ((aalgo->sumsiz)(sav) + 3) & ~(4 - 1);
601 if (AH_MAXSUMSIZE < siz)
602 panic("assertion failed for AH_MAXSUMSIZE");
604 if (esp_auth(m, espoff, m->m_pkthdr.len - espoff, sav, authbuf)) {
605 ipseclog((LOG_ERR, "ESP checksum generation failure\n"));
616 if (!(n->m_flags & M_EXT) && siz < M_TRAILINGSPACE(n)) { /* XXX */
618 m->m_pkthdr.len += siz;
619 p = mtod(n, u_char *) + n->m_len - siz;
623 MGET(nn, MB_DONTWAIT, MT_DATA);
625 ipseclog((LOG_DEBUG, "can't alloc mbuf in esp%d_output",
635 m->m_pkthdr.len += siz;
636 p = mtod(nn, u_char *);
638 bcopy(authbuf, p, siz);
640 /* modify IP header (for ESP header part only) */
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);
649 "IPv4 ESP output: size exceeds limit\n"));
650 ipsecstat.out_inval++;
659 /* total packet length will be computed in ip6_output() */
668 "NULL mbuf after encryption in esp%d_output", afnumber));
671 stat->out_esphist[sav->alg_enc]++;
672 key_sa_recordxfer(sav, m);
679 panic("something bad in esp_output");
685 esp4_output(struct mbuf *m, struct ipsecrequest *isr)
688 if (m->m_len < sizeof(struct ip)) {
689 ipseclog((LOG_DEBUG, "esp4_output: first mbuf too short\n"));
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);
701 esp6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
702 struct ipsecrequest *isr)
704 if (m->m_len < sizeof(struct ip6_hdr)) {
705 ipseclog((LOG_DEBUG, "esp6_output: first mbuf too short\n"));
709 return esp_output(m, nexthdrp, md, isr, AF_INET6);