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: releng/10.1/sys/netinet6/ip6_ipsec.c 263478 2014-03-21 15:15:30Z glebius $");
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/route.h>
51 #include <net/vnet.h>
52
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/in_var.h>
56 #include <netinet/ip.h>
57 #include <netinet/ip6.h>
58 #include <netinet/in_pcb.h>
59 #include <netinet/ip_var.h>
60 #include <netinet/ip_options.h>
61
62 #include <machine/in_cksum.h>
63
64 #ifdef IPSEC
65 #include <netipsec/ipsec.h>
66 #include <netipsec/ipsec6.h>
67 #include <netipsec/xform.h>
68 #include <netipsec/key.h>
69 #ifdef IPSEC_DEBUG
70 #include <netipsec/key_debug.h>
71 #else
72 #define KEYDEBUG(lev,arg)
73 #endif
74 #endif /*IPSEC*/
75
76 #include <netinet6/ip6_ipsec.h>
77 #include <netinet6/ip6_var.h>
78
79 extern struct protosw inet6sw[];
80
81
82 #ifdef INET6
83 #ifdef IPSEC
84 #ifdef IPSEC_FILTERTUNNEL
85 static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1;
86 #else
87 static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0;
88 #endif
89 #define V_ip6_ipsec6_filtertunnel VNET(ip6_ipsec6_filtertunnel)
90
91 SYSCTL_DECL(_net_inet6_ipsec6);
92 SYSCTL_VNET_INT(_net_inet6_ipsec6, OID_AUTO,
93 filtertunnel, CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel), 0,
94 "If set filter packets from an IPsec tunnel.");
95 #endif /* IPSEC */
96 #endif /* INET6 */
97
98 /*
99 * Check if we have to jump over firewall processing for this packet.
100 * Called from ip6_input().
101 * 1 = jump over firewall, 0 = packet goes through firewall.
102 */
103 int
104 ip6_ipsec_filtertunnel(struct mbuf *m)
105 {
106 #ifdef IPSEC
107
108 /*
109 * Bypass packet filtering for packets previously handled by IPsec.
110 */
111 if (!V_ip6_ipsec6_filtertunnel &&
112 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
113 return 1;
114 #endif
115 return 0;
116 }
117
118 /*
119 * Check if this packet has an active SA and needs to be dropped instead
120 * of forwarded.
121 * Called from ip6_input().
122 * 1 = drop packet, 0 = forward packet.
123 */
124 int
125 ip6_ipsec_fwd(struct mbuf *m)
126 {
127 #ifdef IPSEC
128 struct m_tag *mtag;
129 struct tdb_ident *tdbi;
130 struct secpolicy *sp;
131 int error;
132 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
133 if (mtag != NULL) {
134 tdbi = (struct tdb_ident *)(mtag + 1);
135 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
136 } else {
137 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
138 IP_FORWARDING, &error);
139 }
140 if (sp == NULL) { /* NB: can happen if error */
141 /*XXX error stat???*/
142 DPRINTF(("%s: no SP for forwarding\n", __func__)); /*XXX*/
143 return 1;
144 }
145
146 /*
147 * Check security policy against packet attributes.
148 */
149 error = ipsec_in_reject(sp, m);
150 KEY_FREESP(&sp);
151 if (error) {
152 IP6STAT_INC(ip6s_cantforward);
153 return 1;
154 }
155 #endif /* IPSEC */
156 return 0;
157 }
158
159 /*
160 * Check if protocol type doesn't have a further header and do IPSEC
161 * decryption or reject right now. Protocols with further headers get
162 * their IPSEC treatment within the protocol specific processing.
163 * Called from ip6_input().
164 * 1 = drop packet, 0 = continue processing packet.
165 */
166 int
167 ip6_ipsec_input(struct mbuf *m, int nxt)
168 {
169 #ifdef IPSEC
170 struct m_tag *mtag;
171 struct tdb_ident *tdbi;
172 struct secpolicy *sp;
173 int error;
174 /*
175 * enforce IPsec policy checking if we are seeing last header.
176 * note that we do not visit this with protocols with pcb layer
177 * code - like udp/tcp/raw ip.
178 */
179 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
180 ipsec6_in_reject(m, NULL)) {
181
182 /*
183 * Check if the packet has already had IPsec processing
184 * done. If so, then just pass it along. This tag gets
185 * set during AH, ESP, etc. input handling, before the
186 * packet is returned to the ip input queue for delivery.
187 */
188 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
189 if (mtag != NULL) {
190 tdbi = (struct tdb_ident *)(mtag + 1);
191 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
192 } else {
193 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
194 IP_FORWARDING, &error);
195 }
196 if (sp != NULL) {
197 /*
198 * Check security policy against packet attributes.
199 */
200 error = ipsec_in_reject(sp, m);
201 KEY_FREESP(&sp);
202 } else {
203 /* XXX error stat??? */
204 error = EINVAL;
205 DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/
206 return 1;
207 }
208 if (error)
209 return 1;
210 }
211 #endif /* IPSEC */
212 return 0;
213 }
214
215 /*
216 * Called from ip6_output().
217 * 1 = drop packet, 0 = continue processing packet,
218 * -1 = packet was reinjected and stop processing packet
219 */
220
221 int
222 ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
223 struct ifnet **ifp, struct secpolicy **sp)
224 {
225 #ifdef IPSEC
226 struct tdb_ident *tdbi;
227 struct m_tag *mtag;
228 /* XXX int s; */
229 if (sp == NULL)
230 return 1;
231 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
232 if (mtag != NULL) {
233 tdbi = (struct tdb_ident *)(mtag + 1);
234 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
235 if (*sp == NULL)
236 *error = -EINVAL; /* force silent drop */
237 m_tag_delete(*m, mtag);
238 } else {
239 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
240 error, inp);
241 }
242
243 /*
244 * There are four return cases:
245 * sp != NULL apply IPsec policy
246 * sp == NULL, error == 0 no IPsec handling needed
247 * sp == NULL, error == -EINVAL discard packet w/o error
248 * sp == NULL, error != 0 discard packet, report error
249 */
250 if (*sp != NULL) {
251 /* Loop detection, check if ipsec processing already done */
252 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request"));
253 for (mtag = m_tag_first(*m); mtag != NULL;
254 mtag = m_tag_next(*m, mtag)) {
255 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
256 continue;
257 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
258 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
259 continue;
260 /*
261 * Check if policy has no SA associated with it.
262 * This can happen when an SP has yet to acquire
263 * an SA; e.g. on first reference. If it occurs,
264 * then we let ipsec4_process_packet do its thing.
265 */
266 if ((*sp)->req->sav == NULL)
267 break;
268 tdbi = (struct tdb_ident *)(mtag + 1);
269 if (tdbi->spi == (*sp)->req->sav->spi &&
270 tdbi->proto == (*sp)->req->sav->sah->saidx.proto &&
271 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst,
272 sizeof (union sockaddr_union)) == 0) {
273 /*
274 * No IPsec processing is needed, free
275 * reference to SP.
276 *
277 * NB: null pointer to avoid free at
278 * done: below.
279 */
280 KEY_FREESP(sp), *sp = NULL;
281 goto done;
282 }
283 }
284
285 /*
286 * Do delayed checksums now because we send before
287 * this is done in the normal processing path.
288 * For IPv6 we do delayed checksums in ip6_output.c.
289 */
290 #ifdef INET
291 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
292 ipseclog((LOG_DEBUG,
293 "%s: we do not support IPv4 over IPv6", __func__));
294 in_delayed_cksum(*m);
295 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
296 }
297 #endif
298
299 /*
300 * Preserve KAME behaviour: ENOENT can be returned
301 * when an SA acquire is in progress. Don't propagate
302 * this to user-level; it confuses applications.
303 *
304 * XXX this will go away when the SADB is redone.
305 */
306 if (*error == ENOENT)
307 *error = 0;
308 goto do_ipsec;
309 } else { /* sp == NULL */
310 if (*error != 0) {
311 /*
312 * Hack: -EINVAL is used to signal that a packet
313 * should be silently discarded. This is typically
314 * because we asked key management for an SA and
315 * it was delayed (e.g. kicked up to IKE).
316 */
317 if (*error == -EINVAL)
318 *error = 0;
319 goto bad;
320 } else {
321 /* No IPsec processing for this packet. */
322 }
323 }
324 done:
325 return 0;
326 do_ipsec:
327 return -1;
328 bad:
329 return 1;
330 #endif /* IPSEC */
331 return 0;
332 }
333
334 #if 0
335 /*
336 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
337 * Called from ip_forward().
338 * Returns MTU suggestion for ICMP needfrag reply.
339 */
340 int
341 ip6_ipsec_mtu(struct mbuf *m)
342 {
343 int mtu = 0;
344 /*
345 * If the packet is routed over IPsec tunnel, tell the
346 * originator the tunnel MTU.
347 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
348 * XXX quickhack!!!
349 */
350 #ifdef IPSEC
351 struct secpolicy *sp = NULL;
352 int ipsecerror;
353 int ipsechdr;
354 struct route *ro;
355 sp = ipsec_getpolicybyaddr(m,
356 IPSEC_DIR_OUTBOUND,
357 IP_FORWARDING,
358 &ipsecerror);
359 if (sp != NULL) {
360 /* count IPsec header size */
361 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
362
363 /*
364 * find the correct route for outer IPv4
365 * header, compute tunnel MTU.
366 */
367 if (sp->req != NULL &&
368 sp->req->sav != NULL &&
369 sp->req->sav->sah != NULL) {
370 ro = &sp->req->sav->sah->route_cache.sa_route;
371 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
372 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu :
373 ro->ro_rt->rt_ifp->if_mtu;
374 mtu -= ipsechdr;
375 }
376 }
377 KEY_FREESP(&sp);
378 }
379 #endif /* IPSEC */
380 /* XXX else case missing. */
381 return mtu;
382 }
383 #endif
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