1 /*-
2 * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
3 * 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 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 #include "opt_inet.h"
29 #include "opt_inet6.h"
30 #include "opt_ipsec.h"
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/mbuf.h>
37 #include <sys/protosw.h>
38 #include <sys/socket.h>
39 #include <sys/sockopt.h>
40 #include <sys/sysctl.h>
41
42 #include <netinet/in.h>
43 #include <netinet/in_pcb.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/ip.h>
46 #include <netinet/ip6.h>
47 #include <netinet/ip_var.h>
48 #include <netinet/tcp.h>
49 #include <netinet/udp.h>
50 #include <netinet/udp_var.h>
51
52 #include <netinet6/ip6_var.h>
53
54 #include <net/vnet.h>
55
56 #include <netipsec/ipsec.h>
57 #include <netipsec/esp.h>
58 #include <netipsec/esp_var.h>
59 #include <netipsec/xform.h>
60
61 #include <netipsec/key.h>
62 #include <netipsec/key_debug.h>
63 #include <netipsec/ipsec_support.h>
64 #include <machine/in_cksum.h>
65
66 /*
67 * Handle UDP_ENCAP socket option. Always return with released INP_WLOCK.
68 */
69 int
udp_ipsec_pcbctl(struct inpcb * inp,struct sockopt * sopt)70 udp_ipsec_pcbctl(struct inpcb *inp, struct sockopt *sopt)
71 {
72 struct udpcb *up;
73 int error, optval;
74
75 INP_WLOCK_ASSERT(inp);
76 if (sopt->sopt_name != UDP_ENCAP) {
77 INP_WUNLOCK(inp);
78 return (ENOPROTOOPT);
79 }
80
81 up = intoudpcb(inp);
82 if (sopt->sopt_dir == SOPT_GET) {
83 if (up->u_flags & UF_ESPINUDP)
84 optval = UDP_ENCAP_ESPINUDP;
85 else
86 optval = 0;
87 INP_WUNLOCK(inp);
88 return (sooptcopyout(sopt, &optval, sizeof(optval)));
89 }
90 INP_WUNLOCK(inp);
91
92 error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
93 if (error != 0)
94 return (error);
95
96 INP_WLOCK(inp);
97 switch (optval) {
98 case 0:
99 up->u_flags &= ~UF_ESPINUDP;
100 break;
101 case UDP_ENCAP_ESPINUDP:
102 up->u_flags |= UF_ESPINUDP;
103 break;
104 default:
105 error = EINVAL;
106 }
107 INP_WUNLOCK(inp);
108 return (error);
109 }
110
111 /*
112 * Potentially decap ESP in UDP frame. Check for an ESP header.
113 * If present, strip the UDP header and push the result through IPSec.
114 *
115 * Returns error if mbuf consumed and/or processed, otherwise 0.
116 */
117 int
udp_ipsec_input(struct mbuf * m,int off,int af)118 udp_ipsec_input(struct mbuf *m, int off, int af)
119 {
120 union sockaddr_union dst;
121 struct secasvar *sav;
122 struct udphdr *udp;
123 uint32_t spi;
124 int hlen;
125
126 /*
127 * Just return if packet doesn't have enough data.
128 * We need at least [IP header + UDP header + ESP header].
129 * NAT-Keepalive packet has only one byte of payload, so it
130 * by default will not be processed.
131 */
132 if (m->m_pkthdr.len < off + sizeof(struct esp))
133 return (0);
134
135 m_copydata(m, off, sizeof(uint32_t), (caddr_t)&spi);
136 if (spi == 0) /* Non-ESP marker. */
137 return (0);
138
139 /*
140 * Find SA and check that it is configured for UDP
141 * encapsulation.
142 */
143 bzero(&dst, sizeof(dst));
144 dst.sa.sa_family = af;
145 switch (af) {
146 #ifdef INET
147 case AF_INET: {
148 struct ip *ip;
149
150 dst.sin.sin_len = sizeof(struct sockaddr_in);
151 ip = mtod(m, struct ip *);
152 ip->ip_p = IPPROTO_ESP;
153 off = offsetof(struct ip, ip_p);
154 hlen = ip->ip_hl << 2;
155 dst.sin.sin_addr = ip->ip_dst;
156 break;
157 }
158 #endif
159 #ifdef INET6
160 case AF_INET6: {
161 struct ip6_hdr *ip6;
162
163 dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
164 ip6 = mtod(m, struct ip6_hdr *);
165 ip6->ip6_nxt = IPPROTO_ESP;
166 off = offsetof(struct ip6_hdr, ip6_nxt);
167 hlen = sizeof(struct ip6_hdr);
168 dst.sin6.sin6_addr = ip6->ip6_dst;
169 break;
170 }
171 #endif
172 default:
173 ESPSTAT_INC(esps_nopf);
174 m_freem(m);
175 return (EPFNOSUPPORT);
176 }
177
178 sav = key_allocsa(&dst, IPPROTO_ESP, spi);
179 if (sav == NULL) {
180 ESPSTAT_INC(esps_notdb);
181 m_freem(m);
182 return (ENOENT);
183 }
184 udp = mtodo(m, hlen);
185 if (sav->natt == NULL ||
186 sav->natt->sport != udp->uh_sport ||
187 sav->natt->dport != udp->uh_dport) {
188 /* XXXAE: should we check source address? */
189 ESPSTAT_INC(esps_notdb);
190 key_freesav(&sav);
191 m_freem(m);
192 return (ENOENT);
193 }
194 /*
195 * Remove the UDP header
196 * Before:
197 * <--- off --->
198 * +----+------+-----+
199 * | IP | UDP | ESP |
200 * +----+------+-----+
201 * <-skip->
202 * After:
203 * +----+-----+
204 * | IP | ESP |
205 * +----+-----+
206 * <-skip->
207 */
208 m_striphdr(m, hlen, sizeof(*udp));
209
210 /*
211 * We cannot yet update the cksums so clear any h/w cksum flags
212 * as they are no longer valid.
213 */
214 switch (af) {
215 #ifdef INET
216 case AF_INET:
217 if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)
218 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
219 break;
220 #endif /* INET */
221 #ifdef INET6
222 case AF_INET6:
223 if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID_IPV6)
224 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR);
225 break;
226 #endif /* INET6 */
227 default:
228 ESPSTAT_INC(esps_nopf);
229 m_freem(m);
230 return (EPFNOSUPPORT);
231 }
232
233 /*
234 * We can update ip_len and ip_sum here, but ipsec4_input_cb()
235 * will do this anyway, so don't touch them here.
236 */
237 ESPSTAT_INC(esps_input);
238 (*sav->tdb_xform->xf_input)(m, sav, hlen, off);
239 return (EINPROGRESS); /* Consumed by IPsec. */
240 }
241
242 int
udp_ipsec_output(struct mbuf * m,struct secasvar * sav)243 udp_ipsec_output(struct mbuf *m, struct secasvar *sav)
244 {
245 struct udphdr *udp;
246 struct mbuf *n;
247 int hlen, off;
248
249 IPSEC_ASSERT(sav->natt != NULL, ("UDP encapsulation isn't required."));
250
251 switch (sav->sah->saidx.dst.sa.sa_family) {
252 #ifdef INET
253 case AF_INET: {
254 struct ip *ip;
255 ip = mtod(m, struct ip *);
256 hlen = ip->ip_hl << 2;
257 break;
258 }
259 #endif
260 #ifdef INET6
261 case AF_INET6:
262 hlen = sizeof(struct ip6_hdr);
263 break;
264 #endif
265 default:
266 ESPSTAT_INC(esps_nopf);
267 return (EAFNOSUPPORT);
268 }
269
270 n = m_makespace(m, hlen, sizeof(*udp), &off);
271 if (n == NULL) {
272 DPRINTF(("%s: m_makespace for udphdr failed\n", __func__));
273 return (ENOBUFS);
274 }
275
276 udp = mtodo(n, off);
277 udp->uh_dport = sav->natt->dport;
278 udp->uh_sport = sav->natt->sport;
279 udp->uh_sum = 0;
280 udp->uh_ulen = htons(m->m_pkthdr.len - hlen);
281
282 switch (sav->sah->saidx.dst.sa.sa_family) {
283 #ifdef INET
284 case AF_INET: {
285 struct ip *ip;
286
287 ip = mtod(m, struct ip *);
288 ip->ip_len = htons(m->m_pkthdr.len);
289 ip->ip_p = IPPROTO_UDP;
290 break;
291 }
292 #endif
293 #ifdef INET6
294 case AF_INET6: {
295 struct ip6_hdr *ip6;
296
297 ip6 = mtod(m, struct ip6_hdr *);
298 KASSERT(ip6->ip6_nxt == IPPROTO_ESP,
299 ("unexpected next header type %d", ip6->ip6_nxt));
300 ip6->ip6_plen = htons(m->m_pkthdr.len);
301 ip6->ip6_nxt = IPPROTO_UDP;
302 udp->uh_sum = in6_cksum_pseudo(ip6,
303 m->m_pkthdr.len - hlen, ip6->ip6_nxt, 0);
304 m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
305 m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
306 break;
307 }
308 #endif
309 default:
310 ESPSTAT_INC(esps_nopf);
311 return (EAFNOSUPPORT);
312 }
313
314 return (0);
315 }
316
317 void
udp_ipsec_adjust_cksum(struct mbuf * m,struct secasvar * sav,int proto,int skip)318 udp_ipsec_adjust_cksum(struct mbuf *m, struct secasvar *sav, int proto,
319 int skip)
320 {
321 uint16_t cksum, off;
322
323 IPSEC_ASSERT(sav->natt != NULL, ("NAT-T isn't required"));
324 IPSEC_ASSERT(proto == IPPROTO_UDP || proto == IPPROTO_TCP,
325 ("unexpected protocol %u", proto));
326
327 if (proto == IPPROTO_UDP)
328 off = offsetof(struct udphdr, uh_sum);
329 else
330 off = offsetof(struct tcphdr, th_sum);
331
332 if (V_natt_cksum_policy == 0) { /* auto */
333 if (sav->natt->cksum != 0) {
334 /* Incrementally recompute. */
335 m_copydata(m, skip + off, sizeof(cksum),
336 (caddr_t)&cksum);
337 /* Do not adjust UDP checksum if it is zero. */
338 if (proto == IPPROTO_UDP && cksum == 0)
339 return;
340 cksum = in_addword(cksum, sav->natt->cksum);
341 } else {
342 /* No OA from IKEd. */
343 if (proto == IPPROTO_TCP) {
344 /* Ignore for TCP. */
345 m->m_pkthdr.csum_data = 0xffff;
346 switch (sav->sah->saidx.dst.sa.sa_family) {
347 #ifdef INET
348 case AF_INET:
349 m->m_pkthdr.csum_flags |= (CSUM_DATA_VALID |
350 CSUM_PSEUDO_HDR);
351 break;
352 #endif
353 #ifdef INET6
354 case AF_INET6:
355 m->m_pkthdr.csum_flags |= (CSUM_DATA_VALID_IPV6 |
356 CSUM_PSEUDO_HDR);
357 break;
358 #endif
359 default:
360 break;
361 }
362 return;
363 }
364 cksum = 0; /* Reset for UDP. */
365 }
366 m_copyback(m, skip + off, sizeof(cksum), (caddr_t)&cksum);
367 } else { /* Fully recompute */
368 switch (sav->sah->saidx.dst.sa.sa_family) {
369 #ifdef INET
370 case AF_INET: {
371 struct ip *ip;
372
373 ip = mtod(m, struct ip *);
374 cksum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
375 htons(m->m_pkthdr.len - skip + proto));
376 m_copyback(m, skip + off, sizeof(cksum),
377 (caddr_t)&cksum);
378 m->m_pkthdr.csum_flags =
379 (proto == IPPROTO_UDP) ? CSUM_UDP : CSUM_TCP;
380 m->m_pkthdr.csum_data = off;
381 in_delayed_cksum(m);
382 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
383 break;
384 }
385 #endif
386 #ifdef INET6
387 case AF_INET6: {
388 struct ip6_hdr *ip6;
389
390 ip6 = mtod(m, struct ip6_hdr *);
391 cksum = in6_cksum_pseudo(ip6, m->m_pkthdr.len - skip,
392 proto, 0);
393 m_copyback(m, skip + off, sizeof(cksum),
394 (caddr_t)&cksum);
395 m->m_pkthdr.csum_flags =
396 (proto == IPPROTO_UDP) ? CSUM_UDP_IPV6 : CSUM_TCP_IPV6;
397 m->m_pkthdr.csum_data = off;
398 in6_delayed_cksum(m,
399 m->m_pkthdr.len - sizeof(struct ip6_hdr),
400 sizeof(struct ip6_hdr));
401 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
402 break;
403 }
404 #endif
405 default:
406 break;
407 }
408 }
409 }
410