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: src/sys/netinet6/ip6_ipsec.c,v 1.14 2008/12/02 21:37:28 bz Exp $");
32
33 #include "opt_ipsec.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/mac.h>
39 #include <sys/malloc.h>
40 #include <sys/mbuf.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/sysctl.h>
45 #include <sys/vimage.h>
46
47 #include <net/if.h>
48 #include <net/route.h>
49
50 #include <netinet/in.h>
51 #include <netinet/in_systm.h>
52 #include <netinet/in_var.h>
53 #include <netinet/ip.h>
54 #include <netinet/ip6.h>
55 #include <netinet/in_pcb.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/ip_options.h>
58
59 #include <machine/in_cksum.h>
60
61 #ifdef IPSEC
62 #include <netipsec/ipsec.h>
63 #include <netipsec/ipsec6.h>
64 #include <netipsec/xform.h>
65 #include <netipsec/key.h>
66 #ifdef IPSEC_DEBUG
67 #include <netipsec/key_debug.h>
68 #else
69 #define KEYDEBUG(lev,arg)
70 #endif
71 #endif /*IPSEC*/
72
73 #include <netinet6/ip6_ipsec.h>
74 #include <netinet6/ip6_var.h>
75 #include <netinet6/vinet6.h>
76
77 extern struct protosw inet6sw[];
78
79 /*
80 * Check if we have to jump over firewall processing for this packet.
81 * Called from ip_input().
82 * 1 = jump over firewall, 0 = packet goes through firewall.
83 */
84 int
85 ip6_ipsec_filtertunnel(struct mbuf *m)
86 {
87 #if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
88 /*
89 * Bypass packet filtering for packets from a tunnel.
90 */
91 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
92 return 1;
93 #endif
94 return 0;
95 }
96
97 /*
98 * Check if this packet has an active SA and needs to be dropped instead
99 * of forwarded.
100 * Called from ip_input().
101 * 1 = drop packet, 0 = forward packet.
102 */
103 int
104 ip6_ipsec_fwd(struct mbuf *m)
105 {
106 #ifdef IPSEC
107 INIT_VNET_INET6(curvnet);
108 INIT_VNET_IPSEC(curvnet);
109 struct m_tag *mtag;
110 struct tdb_ident *tdbi;
111 struct secpolicy *sp;
112 int s, error;
113 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
114 s = splnet();
115 if (mtag != NULL) {
116 tdbi = (struct tdb_ident *)(mtag + 1);
117 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
118 } else {
119 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
120 IP_FORWARDING, &error);
121 }
122 if (sp == NULL) { /* NB: can happen if error */
123 splx(s);
124 /*XXX error stat???*/
125 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
126 return 1;
127 }
128
129 /*
130 * Check security policy against packet attributes.
131 */
132 error = ipsec_in_reject(sp, m);
133 KEY_FREESP(&sp);
134 splx(s);
135 if (error) {
136 V_ip6stat.ip6s_cantforward++;
137 return 1;
138 }
139 #endif /* IPSEC */
140 return 0;
141 }
142
143 /*
144 * Check if protocol type doesn't have a further header and do IPSEC
145 * decryption or reject right now. Protocols with further headers get
146 * their IPSEC treatment within the protocol specific processing.
147 * Called from ip_input().
148 * 1 = drop packet, 0 = continue processing packet.
149 */
150 int
151 ip6_ipsec_input(struct mbuf *m, int nxt)
152 {
153 #ifdef IPSEC
154 INIT_VNET_IPSEC(curvnet);
155 struct m_tag *mtag;
156 struct tdb_ident *tdbi;
157 struct secpolicy *sp;
158 int s, error;
159 /*
160 * enforce IPsec policy checking if we are seeing last header.
161 * note that we do not visit this with protocols with pcb layer
162 * code - like udp/tcp/raw ip.
163 */
164 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
165 ipsec6_in_reject(m, NULL)) {
166
167 /*
168 * Check if the packet has already had IPsec processing
169 * done. If so, then just pass it along. This tag gets
170 * set during AH, ESP, etc. input handling, before the
171 * packet is returned to the ip input queue for delivery.
172 */
173 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
174 s = splnet();
175 if (mtag != NULL) {
176 tdbi = (struct tdb_ident *)(mtag + 1);
177 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
178 } else {
179 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
180 IP_FORWARDING, &error);
181 }
182 if (sp != NULL) {
183 /*
184 * Check security policy against packet attributes.
185 */
186 error = ipsec_in_reject(sp, m);
187 KEY_FREESP(&sp);
188 } else {
189 /* XXX error stat??? */
190 error = EINVAL;
191 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
192 return 1;
193 }
194 splx(s);
195 if (error)
196 return 1;
197 }
198 #endif /* IPSEC */
199 return 0;
200 }
201
202 /*
203 * Called from ip6_output().
204 * 1 = drop packet, 0 = continue processing packet,
205 * -1 = packet was reinjected and stop processing packet
206 */
207
208 int
209 ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
210 struct ifnet **ifp, struct secpolicy **sp)
211 {
212 #ifdef IPSEC
213 struct tdb_ident *tdbi;
214 struct m_tag *mtag;
215 /* XXX int s; */
216 if (sp == NULL)
217 return 1;
218 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
219 if (mtag != NULL) {
220 tdbi = (struct tdb_ident *)(mtag + 1);
221 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
222 if (*sp == NULL)
223 *error = -EINVAL; /* force silent drop */
224 m_tag_delete(*m, mtag);
225 } else {
226 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
227 error, inp);
228 }
229
230 /*
231 * There are four return cases:
232 * sp != NULL apply IPsec policy
233 * sp == NULL, error == 0 no IPsec handling needed
234 * sp == NULL, error == -EINVAL discard packet w/o error
235 * sp == NULL, error != 0 discard packet, report error
236 */
237 if (*sp != NULL) {
238 /* Loop detection, check if ipsec processing already done */
239 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request"));
240 for (mtag = m_tag_first(*m); mtag != NULL;
241 mtag = m_tag_next(*m, mtag)) {
242 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
243 continue;
244 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
245 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
246 continue;
247 /*
248 * Check if policy has an SA associated with it.
249 * This can happen when an SP has yet to acquire
250 * an SA; e.g. on first reference. If it occurs,
251 * then we let ipsec4_process_packet do its thing.
252 */
253 if ((*sp)->req->sav == NULL)
254 break;
255 tdbi = (struct tdb_ident *)(mtag + 1);
256 if (tdbi->spi == (*sp)->req->sav->spi &&
257 tdbi->proto == (*sp)->req->sav->sah->saidx.proto &&
258 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst,
259 sizeof (union sockaddr_union)) == 0) {
260 /*
261 * No IPsec processing is needed, free
262 * reference to SP.
263 *
264 * NB: null pointer to avoid free at
265 * done: below.
266 */
267 KEY_FREESP(sp), *sp = NULL;
268 /* XXX splx(s); */
269 goto done;
270 }
271 }
272
273 /*
274 * Do delayed checksums now because we send before
275 * this is done in the normal processing path.
276 */
277 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
278 in_delayed_cksum(*m);
279 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
280 }
281
282 /*
283 * Preserve KAME behaviour: ENOENT can be returned
284 * when an SA acquire is in progress. Don't propagate
285 * this to user-level; it confuses applications.
286 *
287 * XXX this will go away when the SADB is redone.
288 */
289 if (*error == ENOENT)
290 *error = 0;
291 goto do_ipsec;
292 } else { /* sp == NULL */
293 if (*error != 0) {
294 /*
295 * Hack: -EINVAL is used to signal that a packet
296 * should be silently discarded. This is typically
297 * because we asked key management for an SA and
298 * it was delayed (e.g. kicked up to IKE).
299 */
300 if (*error == -EINVAL)
301 *error = 0;
302 goto bad;
303 } else {
304 /* No IPsec processing for this packet. */
305 }
306 }
307 done:
308 return 0;
309 do_ipsec:
310 return -1;
311 bad:
312 return 1;
313 #endif /* IPSEC */
314 return 0;
315 }
316
317 #if 0
318 /*
319 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
320 * Called from ip_forward().
321 * Returns MTU suggestion for ICMP needfrag reply.
322 */
323 int
324 ip6_ipsec_mtu(struct mbuf *m)
325 {
326 int mtu = 0;
327 /*
328 * If the packet is routed over IPsec tunnel, tell the
329 * originator the tunnel MTU.
330 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
331 * XXX quickhack!!!
332 */
333 #ifdef IPSEC
334 struct secpolicy *sp = NULL;
335 int ipsecerror;
336 int ipsechdr;
337 struct route *ro;
338 sp = ipsec_getpolicybyaddr(m,
339 IPSEC_DIR_OUTBOUND,
340 IP_FORWARDING,
341 &ipsecerror);
342 if (sp != NULL) {
343 /* count IPsec header size */
344 ipsechdr = ipsec4_hdrsiz(m,
345 IPSEC_DIR_OUTBOUND,
346 NULL);
347
348 /*
349 * find the correct route for outer IPv4
350 * header, compute tunnel MTU.
351 */
352 if (sp->req != NULL &&
353 sp->req->sav != NULL &&
354 sp->req->sav->sah != NULL) {
355 ro = &sp->req->sav->sah->sa_route;
356 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
357 mtu =
358 ro->ro_rt->rt_rmx.rmx_mtu ?
359 ro->ro_rt->rt_rmx.rmx_mtu :
360 ro->ro_rt->rt_ifp->if_mtu;
361 mtu -= ipsechdr;
362 }
363 }
364 KEY_FREESP(&sp);
365 }
366 #endif /* IPSEC */
367 /* XXX else case missing. */
368 return mtu;
369 }
370 #endif
371
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