1/*	$FreeBSD: src/sys/netinet6/ipcomp_input.c,v 1.1.2.2 2001/07/03 11:01:54 ume Exp $	*/
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
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/malloc.h>
41#include <sys/mbuf.h>
42#include <sys/mcache.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/kernel.h>
49#include <sys/syslog.h>
50
51#include <net/if.h>
52#include <net/route.h>
53#include <libkern/zlib.h>
54#include <kern/cpu_number.h>
55#include <kern/locks.h>
56
57#include <netinet/in.h>
58#include <netinet/in_systm.h>
59#include <netinet/in_var.h>
60#include <netinet/ip.h>
61#include <netinet/ip_var.h>
62#include <netinet/ip_ecn.h>
63#include <netinet/kpi_ipfilter_var.h>
64
65#if INET6
66#include <netinet/ip6.h>
67#include <netinet6/ip6_var.h>
68#endif
69#include <netinet6/ipcomp.h>
70#if INET6
71#include <netinet6/ipcomp6.h>
72#endif
73
74#include <netinet6/ipsec.h>
75#if INET6
76#include <netinet6/ipsec6.h>
77#endif
78#include <netkey/key.h>
79#include <netkey/keydb.h>
80
81#include <net/net_osdep.h>
82#include <mach/sdt.h>
83
84#define IPLEN_FLIPPED
85
86void
87ipcomp4_input(struct mbuf *m, int off)
88{
89	struct mbuf *md;
90	struct ip *ip;
91	struct ipcomp *ipcomp;
92	const struct ipcomp_algorithm *algo;
93	u_int16_t cpi;	/* host order */
94	u_int16_t nxt;
95	size_t hlen;
96	int error;
97	size_t newlen, olen;
98	struct secasvar *sav = NULL;
99
100	if (m->m_pkthdr.len < off + sizeof(struct ipcomp)) {
101		ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
102		    "(packet too short)\n"));
103		IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
104		goto fail;
105	}
106
107	md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
108	if (!md) {
109		m = NULL;	/*already freed*/
110		ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
111		    "(pulldown failure)\n"));
112		IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
113		goto fail;
114	}
115	ipcomp = mtod(md, struct ipcomp *);
116
117	/* Expect 32-bit aligned data pointer on strict-align platforms */
118	MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
119
120	ip = mtod(m, struct ip *);
121	nxt = ipcomp->comp_nxt;
122#ifdef _IP_VHL
123	hlen = IP_VHL_HL(ip->ip_vhl) << 2;
124#else
125	hlen = ip->ip_hl << 2;
126#endif
127
128	cpi = ntohs(ipcomp->comp_cpi);
129
130	if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
131		sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src,
132			(caddr_t)&ip->ip_dst, IPPROTO_IPCOMP, htonl(cpi));
133		if (sav != NULL
134		 && (sav->state == SADB_SASTATE_MATURE
135		  || sav->state == SADB_SASTATE_DYING)) {
136			cpi = sav->alg_enc;	/*XXX*/
137			/* other parameters to look at? */
138		}
139	}
140	algo = ipcomp_algorithm_lookup(cpi);
141	if (!algo) {
142		ipseclog((LOG_WARNING, "IPv4 IPComp input: unknown cpi %u\n",
143			cpi));
144		IPSEC_STAT_INCREMENT(ipsecstat.in_nosa);
145		goto fail;
146	}
147
148	/* chop ipcomp header */
149	ipcomp = NULL;
150	md->m_data += sizeof(struct ipcomp);
151	md->m_len -= sizeof(struct ipcomp);
152	m->m_pkthdr.len -= sizeof(struct ipcomp);
153#ifdef IPLEN_FLIPPED
154	ip->ip_len -= sizeof(struct ipcomp);
155#else
156	ip->ip_len = htons(ntohs(ip->ip_len) - sizeof(struct ipcomp));
157#endif
158
159	olen = m->m_pkthdr.len;
160	newlen = m->m_pkthdr.len - off;
161	error = (*algo->decompress)(m, m->m_next, &newlen);
162	if (error != 0) {
163		if (error == EINVAL) {
164			IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
165		} else if (error == ENOBUFS)
166			IPSEC_STAT_INCREMENT(ipsecstat.in_nomem);
167		m = NULL;
168		goto fail;
169	}
170	IPSEC_STAT_INCREMENT(ipsecstat.in_comphist[cpi]);
171
172	/*
173	 * returning decompressed packet onto icmp is meaningless.
174	 * mark it decrypted to prevent icmp from attaching original packet.
175	 */
176	m->m_flags |= M_DECRYPTED;
177
178	m->m_pkthdr.len = off + newlen;
179	ip = mtod(m, struct ip *);
180    {
181	size_t len;
182#ifdef IPLEN_FLIPPED
183	len = ip->ip_len;
184#else
185	len = ntohs(ip->ip_len);
186#endif
187	/*
188	 * be careful about underflow.  also, do not assign exact value
189	 * as ip_len is manipulated differently on *BSDs.
190	 */
191	len += m->m_pkthdr.len;
192	len -= olen;
193	if (len & ~0xffff) {
194		/* packet too big after decompress */
195		IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
196		goto fail;
197	}
198#ifdef IPLEN_FLIPPED
199	ip->ip_len = len & 0xffff;
200#else
201	ip->ip_len = htons(len & 0xffff);
202#endif
203	ip->ip_p = nxt;
204    }
205
206	if (sav) {
207		key_sa_recordxfer(sav, m);
208		if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
209			IPSEC_STAT_INCREMENT(ipsecstat.in_nomem);
210			goto fail;
211		}
212		key_freesav(sav, KEY_SADB_UNLOCKED);
213		sav = NULL;
214	}
215
216	if (nxt != IPPROTO_DONE) {
217		if ((ip_protox[nxt]->pr_flags & PR_LASTHDR) != 0 &&
218		    ipsec4_in_reject(m, NULL)) {
219			IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
220			goto fail;
221		}
222
223		DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
224                        struct ip *, ip, struct ifnet *, m->m_pkthdr.rcvif,
225                        struct ip *, ip, struct ip6_hdr *, NULL);
226
227		ip_proto_dispatch_in(m, off, nxt, 0);
228	} else
229		m_freem(m);
230	m = NULL;
231
232	IPSEC_STAT_INCREMENT(ipsecstat.in_success);
233	return;
234
235fail:
236	if (sav)
237		key_freesav(sav, KEY_SADB_UNLOCKED);
238
239	if (m)
240		m_freem(m);
241	return;
242}
243
244#if INET6
245int
246ipcomp6_input(struct mbuf **mp, int *offp, int proto)
247{
248#pragma unused(proto)
249	struct mbuf *m, *md;
250	int off;
251	struct ip6_hdr *ip6;
252	struct ipcomp *ipcomp;
253	const struct ipcomp_algorithm *algo;
254	u_int16_t cpi;	/* host order */
255	u_int16_t nxt;
256	int error;
257	size_t newlen;
258	struct secasvar *sav = NULL;
259	char *prvnxtp;
260
261	m = *mp;
262	off = *offp;
263
264	md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
265	if (!md) {
266		m = NULL;	/*already freed*/
267		ipseclog((LOG_DEBUG, "IPv6 IPComp input: assumption failed "
268		    "(pulldown failure)\n"));
269		IPSEC_STAT_INCREMENT(ipsec6stat.in_inval);
270		goto fail;
271	}
272	ipcomp = mtod(md, struct ipcomp *);
273
274	/* Expect 32-bit aligned data pointer on strict-align platforms */
275	MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
276
277	ip6 = mtod(m, struct ip6_hdr *);
278	nxt = ipcomp->comp_nxt;
279
280	cpi = ntohs(ipcomp->comp_cpi);
281
282	if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
283		sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src,
284			(caddr_t)&ip6->ip6_dst, IPPROTO_IPCOMP, htonl(cpi));
285		if (sav != NULL
286		 && (sav->state == SADB_SASTATE_MATURE
287		  || sav->state == SADB_SASTATE_DYING)) {
288			cpi = sav->alg_enc;	/*XXX*/
289			/* other parameters to look at? */
290		}
291	}
292	algo = ipcomp_algorithm_lookup(cpi);
293	if (!algo) {
294		ipseclog((LOG_WARNING, "IPv6 IPComp input: unknown cpi %u; "
295			"dropping the packet for simplicity\n", cpi));
296		IPSEC_STAT_INCREMENT(ipsec6stat.in_nosa);
297		goto fail;
298	}
299
300	/* chop ipcomp header */
301	ipcomp = NULL;
302	md->m_data += sizeof(struct ipcomp);
303	md->m_len -= sizeof(struct ipcomp);
304	m->m_pkthdr.len -= sizeof(struct ipcomp);
305
306	newlen = m->m_pkthdr.len - off;
307	error = (*algo->decompress)(m, md, &newlen);
308	if (error != 0) {
309		if (error == EINVAL) {
310			IPSEC_STAT_INCREMENT(ipsec6stat.in_inval);
311		} else if (error == ENOBUFS)
312			IPSEC_STAT_INCREMENT(ipsec6stat.in_nomem);
313		m = NULL;
314		goto fail;
315	}
316	IPSEC_STAT_INCREMENT(ipsec6stat.in_comphist[cpi]);
317	m->m_pkthdr.len = off + newlen;
318
319	/*
320	 * returning decompressed packet onto icmp is meaningless.
321	 * mark it decrypted to prevent icmp from attaching original packet.
322	 */
323	m->m_flags |= M_DECRYPTED;
324
325	/* update next header field */
326	prvnxtp = ip6_get_prevhdr(m, off);
327	*prvnxtp = nxt;
328
329	/*
330	 * no need to adjust payload length, as all the IPv6 protocols
331	 * look at m->m_pkthdr.len
332	 */
333
334	if (sav) {
335		key_sa_recordxfer(sav, m);
336		if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
337			IPSEC_STAT_INCREMENT(ipsec6stat.in_nomem);
338			goto fail;
339		}
340		key_freesav(sav, KEY_SADB_UNLOCKED);
341		sav = NULL;
342	}
343	*offp = off;
344	*mp = m;
345	IPSEC_STAT_INCREMENT(ipsec6stat.in_success);
346	return nxt;
347
348fail:
349	if (m)
350		m_freem(m);
351	if (sav)
352		key_freesav(sav, KEY_SADB_UNLOCKED);
353	return IPPROTO_DONE;
354}
355#endif /* INET6 */
356