1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32
33 #include "opt_inet.h"
34 #include "opt_inet6.h"
35 #include "opt_ipsec.h"
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/mac.h>
41 #include <sys/malloc.h>
42 #include <sys/mbuf.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/socketvar.h>
46 #include <sys/sysctl.h>
47 #include <sys/syslog.h>
48
49 #include <net/if.h>
50 #include <net/vnet.h>
51
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/in_var.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip6.h>
57 #include <netinet/in_pcb.h>
58 #include <netinet/ip_var.h>
59 #include <netinet/ip_options.h>
60
61 #include <machine/in_cksum.h>
62
63 #ifdef IPSEC
64 #include <netipsec/ipsec.h>
65 #include <netipsec/ipsec6.h>
66 #include <netipsec/xform.h>
67 #include <netipsec/key.h>
68 #ifdef IPSEC_DEBUG
69 #include <netipsec/key_debug.h>
70 #else
71 #define KEYDEBUG(lev,arg)
72 #endif
73 #endif /*IPSEC*/
74
75 #include <netinet6/ip6_ipsec.h>
76 #include <netinet6/ip6_var.h>
77
78 extern struct protosw inet6sw[];
79
80
81 #ifdef INET6
82 #ifdef IPSEC
83 #ifdef IPSEC_FILTERTUNNEL
84 static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1;
85 #else
86 static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0;
87 #endif
88 #define V_ip6_ipsec6_filtertunnel VNET(ip6_ipsec6_filtertunnel)
89
90 SYSCTL_DECL(_net_inet6_ipsec6);
91 SYSCTL_VNET_INT(_net_inet6_ipsec6, OID_AUTO,
92 filtertunnel, CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel), 0,
93 "If set filter packets from an IPsec tunnel.");
94 #endif /* IPSEC */
95 #endif /* INET6 */
96
97 /*
98 * Check if we have to jump over firewall processing for this packet.
99 * Called from ip6_input().
100 * 1 = jump over firewall, 0 = packet goes through firewall.
101 */
102 int
ip6_ipsec_filtertunnel(struct mbuf * m)103 ip6_ipsec_filtertunnel(struct mbuf *m)
104 {
105 #ifdef IPSEC
106
107 /*
108 * Bypass packet filtering for packets previously handled by IPsec.
109 */
110 if (!V_ip6_ipsec6_filtertunnel &&
111 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
112 return 1;
113 #endif
114 return 0;
115 }
116
117 /*
118 * Check if this packet has an active SA and needs to be dropped instead
119 * of forwarded.
120 * Called from ip6_input().
121 * 1 = drop packet, 0 = forward packet.
122 */
123 int
ip6_ipsec_fwd(struct mbuf * m)124 ip6_ipsec_fwd(struct mbuf *m)
125 {
126 #ifdef IPSEC
127 struct m_tag *mtag;
128 struct tdb_ident *tdbi;
129 struct secpolicy *sp;
130 int error;
131 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
132 if (mtag != NULL) {
133 tdbi = (struct tdb_ident *)(mtag + 1);
134 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
135 } else {
136 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
137 IP_FORWARDING, &error);
138 }
139 if (sp == NULL) { /* NB: can happen if error */
140 /*XXX error stat???*/
141 DPRINTF(("%s: no SP for forwarding\n", __func__)); /*XXX*/
142 return 1;
143 }
144
145 /*
146 * Check security policy against packet attributes.
147 */
148 error = ipsec_in_reject(sp, m);
149 KEY_FREESP(&sp);
150 if (error) {
151 IP6STAT_INC(ip6s_cantforward);
152 return 1;
153 }
154 #endif /* IPSEC */
155 return 0;
156 }
157
158 /*
159 * Check if protocol type doesn't have a further header and do IPSEC
160 * decryption or reject right now. Protocols with further headers get
161 * their IPSEC treatment within the protocol specific processing.
162 * Called from ip6_input().
163 * 1 = drop packet, 0 = continue processing packet.
164 */
165 int
ip6_ipsec_input(struct mbuf * m,int nxt)166 ip6_ipsec_input(struct mbuf *m, int nxt)
167 {
168 #ifdef IPSEC
169 struct m_tag *mtag;
170 struct tdb_ident *tdbi;
171 struct secpolicy *sp;
172 int error;
173 /*
174 * enforce IPsec policy checking if we are seeing last header.
175 * note that we do not visit this with protocols with pcb layer
176 * code - like udp/tcp/raw ip.
177 */
178 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
179 ipsec6_in_reject(m, NULL)) {
180
181 /*
182 * Check if the packet has already had IPsec processing
183 * done. If so, then just pass it along. This tag gets
184 * set during AH, ESP, etc. input handling, before the
185 * packet is returned to the ip input queue for delivery.
186 */
187 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
188 if (mtag != NULL) {
189 tdbi = (struct tdb_ident *)(mtag + 1);
190 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
191 } else {
192 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
193 IP_FORWARDING, &error);
194 }
195 if (sp != NULL) {
196 /*
197 * Check security policy against packet attributes.
198 */
199 error = ipsec_in_reject(sp, m);
200 KEY_FREESP(&sp);
201 } else {
202 /* XXX error stat??? */
203 error = EINVAL;
204 DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/
205 return 1;
206 }
207 if (error)
208 return 1;
209 }
210 #endif /* IPSEC */
211 return 0;
212 }
213
214 /*
215 * Called from ip6_output().
216 * 1 = drop packet, 0 = continue processing packet,
217 * -1 = packet was reinjected and stop processing packet
218 */
219
220 int
ip6_ipsec_output(struct mbuf ** m,struct inpcb * inp,int * flags,int * error,struct ifnet ** ifp)221 ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
222 struct ifnet **ifp)
223 {
224 #ifdef IPSEC
225 struct secpolicy *sp = NULL;
226 struct tdb_ident *tdbi;
227 struct m_tag *mtag;
228 /* XXX int s; */
229 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
230 if (mtag != NULL) {
231 tdbi = (struct tdb_ident *)(mtag + 1);
232 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
233 if (sp == NULL)
234 *error = -EINVAL; /* force silent drop */
235 m_tag_delete(*m, mtag);
236 } else {
237 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
238 error, inp);
239 }
240
241 /*
242 * There are four return cases:
243 * sp != NULL apply IPsec policy
244 * sp == NULL, error == 0 no IPsec handling needed
245 * sp == NULL, error == -EINVAL discard packet w/o error
246 * sp == NULL, error != 0 discard packet, report error
247 */
248 if (sp != NULL) {
249 /* Loop detection, check if ipsec processing already done */
250 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
251 for (mtag = m_tag_first(*m); mtag != NULL;
252 mtag = m_tag_next(*m, mtag)) {
253 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
254 continue;
255 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
256 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
257 continue;
258 /*
259 * Check if policy has no SA associated with it.
260 * This can happen when an SP has yet to acquire
261 * an SA; e.g. on first reference. If it occurs,
262 * then we let ipsec4_process_packet do its thing.
263 */
264 if (sp->req->sav == NULL)
265 break;
266 tdbi = (struct tdb_ident *)(mtag + 1);
267 if (tdbi->spi == sp->req->sav->spi &&
268 tdbi->proto == sp->req->sav->sah->saidx.proto &&
269 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
270 sizeof (union sockaddr_union)) == 0) {
271 /*
272 * No IPsec processing is needed, free
273 * reference to SP.
274 */
275 goto done;
276 }
277 }
278
279 /*
280 * Do delayed checksums now because we send before
281 * this is done in the normal processing path.
282 */
283 #ifdef INET
284 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
285 in_delayed_cksum(*m);
286 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
287 }
288 #endif
289 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
290 in6_delayed_cksum(*m, (*m)->m_pkthdr.len - sizeof(struct ip6_hdr),
291 sizeof(struct ip6_hdr));
292 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
293 }
294 #ifdef SCTP
295 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
296 sctp_delayed_cksum(*m, sizeof(struct ip6_hdr));
297 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
298 }
299 #endif
300
301 /* NB: callee frees mbuf */
302 *error = ipsec6_process_packet(*m, sp->req);
303
304 if (*error == EJUSTRETURN) {
305 /*
306 * We had a SP with a level of 'use' and no SA. We
307 * will just continue to process the packet without
308 * IPsec processing.
309 */
310 *error = 0;
311 goto done;
312 }
313
314 /*
315 * Preserve KAME behaviour: ENOENT can be returned
316 * when an SA acquire is in progress. Don't propagate
317 * this to user-level; it confuses applications.
318 *
319 * XXX this will go away when the SADB is redone.
320 */
321 if (*error == ENOENT)
322 *error = 0;
323 goto reinjected;
324 } else { /* sp == NULL */
325 if (*error != 0) {
326 /*
327 * Hack: -EINVAL is used to signal that a packet
328 * should be silently discarded. This is typically
329 * because we asked key management for an SA and
330 * it was delayed (e.g. kicked up to IKE).
331 */
332 if (*error == -EINVAL)
333 *error = 0;
334 goto bad;
335 } else {
336 /* No IPsec processing for this packet. */
337 }
338 }
339 done:
340 if (sp != NULL)
341 KEY_FREESP(&sp);
342 return 0;
343 reinjected:
344 if (sp != NULL)
345 KEY_FREESP(&sp);
346 return -1;
347 bad:
348 if (sp != NULL)
349 KEY_FREESP(&sp);
350 return 1;
351 #endif /* IPSEC */
352 return 0;
353 }
354
355 #if 0
356 /*
357 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
358 * Called from ip_forward().
359 * Returns MTU suggestion for ICMP needfrag reply.
360 */
361 int
362 ip6_ipsec_mtu(struct mbuf *m)
363 {
364 int mtu = 0;
365 /*
366 * If the packet is routed over IPsec tunnel, tell the
367 * originator the tunnel MTU.
368 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
369 * XXX quickhack!!!
370 */
371 #ifdef IPSEC
372 struct secpolicy *sp = NULL;
373 int ipsecerror;
374 int ipsechdr;
375 struct route *ro;
376 sp = ipsec_getpolicybyaddr(m,
377 IPSEC_DIR_OUTBOUND,
378 IP_FORWARDING,
379 &ipsecerror);
380 if (sp != NULL) {
381 /* count IPsec header size */
382 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
383
384 /*
385 * find the correct route for outer IPv4
386 * header, compute tunnel MTU.
387 */
388 if (sp->req != NULL &&
389 sp->req->sav != NULL &&
390 sp->req->sav->sah != NULL) {
391 ro = &sp->req->sav->sah->route_cache.sa_route;
392 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
393 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu :
394 ro->ro_rt->rt_ifp->if_mtu;
395 mtu -= ipsechdr;
396 }
397 }
398 KEY_FREESP(&sp);
399 }
400 #endif /* IPSEC */
401 /* XXX else case missing. */
402 return mtu;
403 }
404 #endif
405