1 /* $FreeBSD$ */
2 /* $KAME: ipcomp_input.c,v 1.25 2001/03/01 09:12:09 itojun Exp $ */
3
4 /*-
5 * Copyright (C) 1999 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * RFC2393 IP payload compression protocol (IPComp).
35 */
36
37 #include "opt_inet.h"
38 #include "opt_inet6.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/mbuf.h>
43 #include <sys/domain.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/errno.h>
47 #include <sys/time.h>
48 #include <sys/syslog.h>
49
50 #include <net/if.h>
51 #include <net/route.h>
52 #include <net/netisr.h>
53 #include <net/zlib.h>
54 #include <machine/cpu.h>
55
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/in_var.h>
59 #include <netinet/ip.h>
60 #include <netinet/ip_var.h>
61 #include <netinet/ip_ecn.h>
62
63 #ifdef INET6
64 #include <netinet/ip6.h>
65 #include <netinet6/ip6_var.h>
66 #endif
67 #include <netinet6/ipcomp.h>
68 #ifdef INET6
69 #include <netinet6/ipcomp6.h>
70 #endif
71
72 #include <netinet6/ipsec.h>
73 #ifdef INET6
74 #include <netinet6/ipsec6.h>
75 #endif
76 #include <netkey/key.h>
77 #include <netkey/keydb.h>
78
79 #include <machine/stdarg.h>
80
81 #include <net/net_osdep.h>
82
83 #define IPLEN_FLIPPED
84
85 #ifdef INET
86 extern struct protosw inetsw[];
87
88 void
89 ipcomp4_input(m, off)
90 struct mbuf *m;
91 int off;
92 {
93 struct mbuf *md;
94 struct ip *ip;
95 struct ipcomp *ipcomp;
96 const struct ipcomp_algorithm *algo;
97 u_int16_t cpi; /* host order */
98 u_int16_t nxt;
99 size_t hlen;
100 int error;
101 size_t newlen, olen;
102 struct secasvar *sav = NULL;
103
104 if (m->m_pkthdr.len < off + sizeof(struct ipcomp)) {
105 ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
106 "(packet too short)\n"));
107 ipsecstat.in_inval++;
108 goto fail;
109 }
110
111 md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
112 if (!md) {
113 m = NULL; /* already freed */
114 ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
115 "(pulldown failure)\n"));
116 ipsecstat.in_inval++;
117 goto fail;
118 }
119 ipcomp = mtod(md, struct ipcomp *);
120 nxt = ipcomp->comp_nxt;
121
122 /*
123 * Check that the next header of the IPComp is not IPComp again, before
124 * doing any real work. Given it is not possible to do double
125 * compression it means someone is playing tricks on us.
126 */
127 if (nxt == IPPROTO_IPCOMP) {
128 ipseclog((LOG_ERR, "IPv4 IPComp input: "
129 "recursive compression detected."));
130 ipsecstat.in_inval++;
131 goto fail;
132 }
133
134 ip = mtod(m, struct ip *);
135 #ifdef _IP_VHL
136 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
137 #else
138 hlen = ip->ip_hl << 2;
139 #endif
140
141 cpi = ntohs(ipcomp->comp_cpi);
142
143 if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
144 sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src,
145 (caddr_t)&ip->ip_dst, IPPROTO_IPCOMP, htonl(cpi));
146 if (sav != NULL
147 && (sav->state == SADB_SASTATE_MATURE
148 || sav->state == SADB_SASTATE_DYING)) {
149 cpi = sav->alg_enc; /* XXX */
150 /* other parameters to look at? */
151 }
152 }
153 algo = ipcomp_algorithm_lookup(cpi);
154 if (!algo) {
155 ipseclog((LOG_WARNING, "IPv4 IPComp input: unknown cpi %u\n",
156 cpi));
157 ipsecstat.in_nosa++;
158 goto fail;
159 }
160
161 /* chop ipcomp header */
162 ipcomp = NULL;
163 md->m_data += sizeof(struct ipcomp);
164 md->m_len -= sizeof(struct ipcomp);
165 m->m_pkthdr.len -= sizeof(struct ipcomp);
166 #ifdef IPLEN_FLIPPED
167 ip->ip_len -= sizeof(struct ipcomp);
168 #else
169 ip->ip_len = htons(ntohs(ip->ip_len) - sizeof(struct ipcomp));
170 #endif
171
172 olen = m->m_pkthdr.len;
173 newlen = m->m_pkthdr.len - off;
174 error = (*algo->decompress)(m, m->m_next, &newlen);
175 if (error != 0) {
176 if (error == EINVAL)
177 ipsecstat.in_inval++;
178 else if (error == ENOBUFS)
179 ipsecstat.in_nomem++;
180 m = NULL;
181 goto fail;
182 }
183 ipsecstat.in_comphist[cpi]++;
184
185 /*
186 * returning decompressed packet onto icmp is meaningless.
187 * mark it decrypted to prevent icmp from attaching original packet.
188 */
189 m->m_flags |= M_DECRYPTED;
190
191 m->m_pkthdr.len = off + newlen;
192 ip = mtod(m, struct ip *);
193 {
194 size_t len;
195 #ifdef IPLEN_FLIPPED
196 len = ip->ip_len;
197 #else
198 len = ntohs(ip->ip_len);
199 #endif
200 /*
201 * be careful about underflow. also, do not assign exact value
202 * as ip_len is manipulated differently on *BSDs.
203 */
204 len += m->m_pkthdr.len;
205 len -= olen;
206 if (len & ~0xffff) {
207 /* packet too big after decompress */
208 ipsecstat.in_inval++;
209 goto fail;
210 }
211 #ifdef IPLEN_FLIPPED
212 ip->ip_len = len & 0xffff;
213 #else
214 ip->ip_len = htons(len & 0xffff);
215 #endif
216 ip->ip_p = nxt;
217 }
218
219 if (sav) {
220 key_sa_recordxfer(sav, m);
221 if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
222 ipsecstat.in_nomem++;
223 goto fail;
224 }
225 key_freesav(sav);
226 sav = NULL;
227 }
228
229 if (nxt != IPPROTO_DONE) {
230 if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
231 ipsec4_in_reject(m, NULL)) {
232 ipsecstat.in_polvio++;
233 goto fail;
234 }
235 (*inetsw[ip_protox[nxt]].pr_input)(m, off);
236 } else
237 m_freem(m);
238 m = NULL;
239
240 ipsecstat.in_success++;
241 return;
242
243 fail:
244 if (sav)
245 key_freesav(sav);
246 if (m)
247 m_freem(m);
248 return;
249 }
250 #endif /* INET */
251
252 #ifdef INET6
253 int
254 ipcomp6_input(mp, offp, proto)
255 struct mbuf **mp;
256 int *offp, proto;
257 {
258 struct mbuf *m, *md;
259 int off;
260 struct ip6_hdr *ip6;
261 struct ipcomp *ipcomp;
262 const struct ipcomp_algorithm *algo;
263 u_int16_t cpi; /* host order */
264 u_int16_t nxt;
265 int error;
266 size_t newlen;
267 struct secasvar *sav = NULL;
268 u_int8_t *prvnxtp;
269
270 m = *mp;
271 off = *offp;
272
273 md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
274 if (!md) {
275 m = NULL; /* already freed */
276 ipseclog((LOG_DEBUG, "IPv6 IPComp input: assumption failed "
277 "(pulldown failure)\n"));
278 ipsec6stat.in_inval++;
279 goto fail;
280 }
281 ipcomp = mtod(md, struct ipcomp *);
282 ip6 = mtod(m, struct ip6_hdr *);
283 nxt = ipcomp->comp_nxt;
284
285 /*
286 * Check that the next header of the IPComp is not IPComp again, before
287 * doing any real work. Given it is not possible to do double
288 * compression it means someone is playing tricks on us.
289 */
290 if (nxt == IPPROTO_IPCOMP) {
291 ipseclog((LOG_ERR, "IPv6 IPComp input: "
292 "recursive compression detected."));
293 ipsecstat.in_inval++;
294 goto fail;
295 }
296
297 cpi = ntohs(ipcomp->comp_cpi);
298
299 if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
300 sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src,
301 (caddr_t)&ip6->ip6_dst, IPPROTO_IPCOMP, htonl(cpi));
302 if (sav != NULL
303 && (sav->state == SADB_SASTATE_MATURE
304 || sav->state == SADB_SASTATE_DYING)) {
305 cpi = sav->alg_enc; /* XXX */
306 /* other parameters to look at? */
307 }
308 }
309 algo = ipcomp_algorithm_lookup(cpi);
310 if (!algo) {
311 ipseclog((LOG_WARNING, "IPv6 IPComp input: unknown cpi %u; "
312 "dropping the packet for simplicity\n", cpi));
313 ipsec6stat.in_nosa++;
314 goto fail;
315 }
316
317 /* chop ipcomp header */
318 ipcomp = NULL;
319 md->m_data += sizeof(struct ipcomp);
320 md->m_len -= sizeof(struct ipcomp);
321 m->m_pkthdr.len -= sizeof(struct ipcomp);
322
323 newlen = m->m_pkthdr.len - off;
324 error = (*algo->decompress)(m, md, &newlen);
325 if (error != 0) {
326 if (error == EINVAL)
327 ipsec6stat.in_inval++;
328 else if (error == ENOBUFS)
329 ipsec6stat.in_nomem++;
330 m = NULL;
331 goto fail;
332 }
333 ipsec6stat.in_comphist[cpi]++;
334 m->m_pkthdr.len = off + newlen;
335
336 /*
337 * returning decompressed packet onto icmp is meaningless.
338 * mark it decrypted to prevent icmp from attaching original packet.
339 */
340 m->m_flags |= M_DECRYPTED;
341
342 /* update next header field */
343 prvnxtp = ip6_get_prevhdr(m, off);
344 *prvnxtp = nxt;
345
346 /*
347 * no need to adjust payload length, as all the IPv6 protocols
348 * look at m->m_pkthdr.len
349 */
350
351 if (sav) {
352 key_sa_recordxfer(sav, m);
353 if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
354 ipsec6stat.in_nomem++;
355 goto fail;
356 }
357 key_freesav(sav);
358 sav = NULL;
359 }
360 *offp = off;
361 *mp = m;
362 ipsec6stat.in_success++;
363 return nxt;
364
365 fail:
366 if (m)
367 m_freem(m);
368 if (sav)
369 key_freesav(sav);
370 return IPPROTO_DONE;
371 }
372 #endif /* INET6 */
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