1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2006 The FreeBSD Project.
5 * Copyright (c) 2015 Andrey V. Elsukov <ae@FreeBSD.org>
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 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include "opt_inet.h"
32 #include "opt_inet6.h"
33 #include "opt_ipsec.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/hhook.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/mbuf.h>
41 #include <sys/module.h>
42 #include <machine/bus.h>
43 #include <sys/rman.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 #include <sys/sysctl.h>
47
48 #include <net/if.h>
49 #include <net/if_enc.h>
50 #include <net/if_var.h>
51 #include <net/if_private.h>
52 #include <net/if_clone.h>
53 #include <net/if_types.h>
54 #include <net/pfil.h>
55 #include <net/route.h>
56 #include <net/netisr.h>
57 #include <net/bpf.h>
58 #include <net/vnet.h>
59
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/ip.h>
63 #include <netinet/ip_var.h>
64 #include <netinet/in_var.h>
65
66 #ifdef INET6
67 #include <netinet/ip6.h>
68 #include <netinet6/ip6_var.h>
69 #endif
70
71 #include <netipsec/ipsec.h>
72 #include <netipsec/xform.h>
73
74 #define ENCMTU (1024+512)
75
76 /* XXX this define must have the same value as in OpenBSD */
77 #define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */
78 #define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */
79 #define M_AUTH_AH 0x2000 /* header was authenticated (AH) */
80
81 struct enchdr {
82 u_int32_t af;
83 u_int32_t spi;
84 u_int32_t flags;
85 };
86 struct enc_softc {
87 struct ifnet *sc_ifp;
88 };
89 VNET_DEFINE_STATIC(struct enc_softc *, enc_sc);
90 #define V_enc_sc VNET(enc_sc)
91 VNET_DEFINE_STATIC(struct if_clone *, enc_cloner);
92 #define V_enc_cloner VNET(enc_cloner)
93
94 static int enc_ioctl(struct ifnet *, u_long, caddr_t);
95 static int enc_output(struct ifnet *, struct mbuf *,
96 const struct sockaddr *, struct route *);
97 static int enc_clone_create(struct if_clone *, int, caddr_t);
98 static void enc_clone_destroy(struct ifnet *);
99 static int enc_add_hhooks(struct enc_softc *);
100 static void enc_remove_hhooks(struct enc_softc *);
101
102 static const char encname[] = "enc";
103
104 #define IPSEC_ENC_AFTER_PFIL 0x04
105 /*
106 * Before and after are relative to when we are stripping the
107 * outer IP header.
108 *
109 * AFTER_PFIL flag used only for bpf_mask_*. It enables BPF capturing
110 * after PFIL hook execution. It might be useful when PFIL hook does
111 * some changes to the packet, e.g. address translation. If PFIL hook
112 * consumes mbuf, nothing will be captured.
113 */
114 VNET_DEFINE_STATIC(int, filter_mask_in) = IPSEC_ENC_BEFORE;
115 VNET_DEFINE_STATIC(int, bpf_mask_in) = IPSEC_ENC_BEFORE;
116 VNET_DEFINE_STATIC(int, filter_mask_out) = IPSEC_ENC_BEFORE;
117 VNET_DEFINE_STATIC(int, bpf_mask_out) = IPSEC_ENC_BEFORE | IPSEC_ENC_AFTER;
118 #define V_filter_mask_in VNET(filter_mask_in)
119 #define V_bpf_mask_in VNET(bpf_mask_in)
120 #define V_filter_mask_out VNET(filter_mask_out)
121 #define V_bpf_mask_out VNET(bpf_mask_out)
122
123 static SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
124 "enc sysctl");
125 static SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
126 "enc input sysctl");
127 static SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
128 "enc output sysctl");
129 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask,
130 CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_in), 0,
131 "IPsec input firewall filter mask");
132 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask,
133 CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_in), 0,
134 "IPsec input bpf mask");
135 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask,
136 CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_out), 0,
137 "IPsec output firewall filter mask");
138 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask,
139 CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_out), 0,
140 "IPsec output bpf mask");
141
142 static void
enc_clone_destroy(struct ifnet * ifp)143 enc_clone_destroy(struct ifnet *ifp)
144 {
145 struct enc_softc *sc;
146
147 sc = ifp->if_softc;
148 KASSERT(sc == V_enc_sc, ("sc != ifp->if_softc"));
149
150 bpfdetach(ifp);
151 if_detach(ifp);
152 if_free(ifp);
153 free(sc, M_DEVBUF);
154 V_enc_sc = NULL;
155 }
156
157 static int
enc_clone_create(struct if_clone * ifc,int unit,caddr_t params)158 enc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
159 {
160 struct ifnet *ifp;
161 struct enc_softc *sc;
162
163 sc = malloc(sizeof(struct enc_softc), M_DEVBUF,
164 M_WAITOK | M_ZERO);
165 ifp = sc->sc_ifp = if_alloc(IFT_ENC);
166 if (ifp == NULL) {
167 free(sc, M_DEVBUF);
168 return (ENOSPC);
169 }
170 if (V_enc_sc != NULL) {
171 if_free(ifp);
172 free(sc, M_DEVBUF);
173 return (EEXIST);
174 }
175 V_enc_sc = sc;
176 if_initname(ifp, encname, unit);
177 ifp->if_mtu = ENCMTU;
178 ifp->if_ioctl = enc_ioctl;
179 ifp->if_output = enc_output;
180 ifp->if_softc = sc;
181 if_attach(ifp);
182 bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
183 return (0);
184 }
185
186 static int
enc_output(struct ifnet * ifp,struct mbuf * m,const struct sockaddr * dst,struct route * ro)187 enc_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
188 struct route *ro)
189 {
190
191 m_freem(m);
192 return (0);
193 }
194
195 static int
enc_ioctl(struct ifnet * ifp,u_long cmd,caddr_t data)196 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
197 {
198
199 if (cmd != SIOCSIFFLAGS)
200 return (EINVAL);
201 if (ifp->if_flags & IFF_UP)
202 ifp->if_drv_flags |= IFF_DRV_RUNNING;
203 else
204 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
205 return (0);
206 }
207
208 static void
enc_bpftap(struct ifnet * ifp,struct mbuf * m,const struct secasvar * sav,int32_t hhook_type,uint8_t enc,uint8_t af)209 enc_bpftap(struct ifnet *ifp, struct mbuf *m, const struct secasvar *sav,
210 int32_t hhook_type, uint8_t enc, uint8_t af)
211 {
212 struct enchdr hdr;
213
214 if (hhook_type == HHOOK_TYPE_IPSEC_IN &&
215 (enc & V_bpf_mask_in) == 0)
216 return;
217 else if (hhook_type == HHOOK_TYPE_IPSEC_OUT &&
218 (enc & V_bpf_mask_out) == 0)
219 return;
220 if (!bpf_peers_present(ifp->if_bpf))
221 return;
222 hdr.af = af;
223 hdr.spi = sav->spi;
224 hdr.flags = 0;
225 if (sav->alg_enc != SADB_EALG_NONE)
226 hdr.flags |= M_CONF;
227 if (sav->alg_auth != SADB_AALG_NONE)
228 hdr.flags |= M_AUTH;
229 bpf_mtap2(ifp->if_bpf, &hdr, sizeof(hdr), m);
230 }
231
232 /*
233 * One helper hook function is used by any hook points.
234 * + from hhook_type we can determine the packet direction:
235 * HHOOK_TYPE_IPSEC_IN or HHOOK_TYPE_IPSEC_OUT;
236 * + from hhook_id we can determine address family: AF_INET or AF_INET6;
237 * + udata contains pointer to enc_softc;
238 * + ctx_data contains pointer to struct ipsec_ctx_data.
239 */
240 static int
enc_hhook(int32_t hhook_type,int32_t hhook_id,void * udata,void * ctx_data,void * hdata,struct osd * hosd)241 enc_hhook(int32_t hhook_type, int32_t hhook_id, void *udata, void *ctx_data,
242 void *hdata, struct osd *hosd)
243 {
244 struct ipsec_ctx_data *ctx;
245 struct enc_softc *sc;
246 struct ifnet *ifp, *rcvif;
247 struct pfil_head *ph;
248 int pdir, ret;
249
250 sc = (struct enc_softc *)udata;
251 ifp = sc->sc_ifp;
252 if ((ifp->if_flags & IFF_UP) == 0)
253 return (0);
254
255 ctx = (struct ipsec_ctx_data *)ctx_data;
256 /* XXX: wrong hook point was used by caller? */
257 if (ctx->af != hhook_id)
258 return (EPFNOSUPPORT);
259
260 enc_bpftap(ifp, *ctx->mp, ctx->sav, hhook_type, ctx->enc, ctx->af);
261 switch (hhook_type) {
262 case HHOOK_TYPE_IPSEC_IN:
263 if (ctx->enc == IPSEC_ENC_BEFORE) {
264 /* Do accounting only once */
265 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
266 if_inc_counter(ifp, IFCOUNTER_IBYTES,
267 (*ctx->mp)->m_pkthdr.len);
268 }
269 if ((ctx->enc & V_filter_mask_in) == 0)
270 return (0); /* skip pfil processing */
271 pdir = PFIL_IN;
272 break;
273 case HHOOK_TYPE_IPSEC_OUT:
274 if (ctx->enc == IPSEC_ENC_BEFORE) {
275 /* Do accounting only once */
276 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
277 if_inc_counter(ifp, IFCOUNTER_OBYTES,
278 (*ctx->mp)->m_pkthdr.len);
279 }
280 if ((ctx->enc & V_filter_mask_out) == 0)
281 return (0); /* skip pfil processing */
282 pdir = PFIL_OUT;
283 break;
284 default:
285 return (EINVAL);
286 }
287
288 switch (hhook_id) {
289 #ifdef INET
290 case AF_INET:
291 ph = V_inet_pfil_head;
292 break;
293 #endif
294 #ifdef INET6
295 case AF_INET6:
296 ph = V_inet6_pfil_head;
297 break;
298 #endif
299 default:
300 ph = NULL;
301 }
302 if (ph == NULL || (pdir == PFIL_OUT && !PFIL_HOOKED_OUT(ph)) ||
303 (pdir == PFIL_IN && !PFIL_HOOKED_IN(ph)))
304 return (0);
305 /* Make a packet looks like it was received on enc(4) */
306 rcvif = (*ctx->mp)->m_pkthdr.rcvif;
307 (*ctx->mp)->m_pkthdr.rcvif = ifp;
308 if (pdir == PFIL_IN)
309 ret = pfil_mbuf_in(ph, ctx->mp, ifp, ctx->inp);
310 else
311 ret = pfil_mbuf_out(ph, ctx->mp, ifp, ctx->inp);
312 if (ret != PFIL_PASS) {
313 *ctx->mp = NULL; /* consumed by filter */
314 return (EACCES);
315 }
316 (*ctx->mp)->m_pkthdr.rcvif = rcvif;
317 enc_bpftap(ifp, *ctx->mp, ctx->sav, hhook_type,
318 IPSEC_ENC_AFTER_PFIL, ctx->af);
319 return (0);
320 }
321
322 static int
enc_add_hhooks(struct enc_softc * sc)323 enc_add_hhooks(struct enc_softc *sc)
324 {
325 struct hookinfo hki;
326 int error;
327
328 error = EPFNOSUPPORT;
329 hki.hook_func = enc_hhook;
330 hki.hook_helper = NULL;
331 hki.hook_udata = sc;
332 #ifdef INET
333 hki.hook_id = AF_INET;
334 hki.hook_type = HHOOK_TYPE_IPSEC_IN;
335 error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET],
336 &hki, HHOOK_WAITOK);
337 if (error != 0)
338 return (error);
339 hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
340 error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET],
341 &hki, HHOOK_WAITOK);
342 if (error != 0)
343 return (error);
344 #endif
345 #ifdef INET6
346 hki.hook_id = AF_INET6;
347 hki.hook_type = HHOOK_TYPE_IPSEC_IN;
348 error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6],
349 &hki, HHOOK_WAITOK);
350 if (error != 0)
351 return (error);
352 hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
353 error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6],
354 &hki, HHOOK_WAITOK);
355 if (error != 0)
356 return (error);
357 #endif
358 return (error);
359 }
360
361 static void
enc_remove_hhooks(struct enc_softc * sc)362 enc_remove_hhooks(struct enc_softc *sc)
363 {
364 struct hookinfo hki;
365
366 hki.hook_func = enc_hhook;
367 hki.hook_helper = NULL;
368 hki.hook_udata = sc;
369 #ifdef INET
370 hki.hook_id = AF_INET;
371 hki.hook_type = HHOOK_TYPE_IPSEC_IN;
372 hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET], &hki);
373 hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
374 hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET], &hki);
375 #endif
376 #ifdef INET6
377 hki.hook_id = AF_INET6;
378 hki.hook_type = HHOOK_TYPE_IPSEC_IN;
379 hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6], &hki);
380 hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
381 hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6], &hki);
382 #endif
383 }
384
385 static void
vnet_enc_init(const void * unused __unused)386 vnet_enc_init(const void *unused __unused)
387 {
388
389 V_enc_sc = NULL;
390 V_enc_cloner = if_clone_simple(encname, enc_clone_create,
391 enc_clone_destroy, 1);
392 }
393 VNET_SYSINIT(vnet_enc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
394 vnet_enc_init, NULL);
395
396 static void
vnet_enc_init_proto(void * unused __unused)397 vnet_enc_init_proto(void *unused __unused)
398 {
399 KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
400
401 if (enc_add_hhooks(V_enc_sc) != 0)
402 enc_clone_destroy(V_enc_sc->sc_ifp);
403 }
404 VNET_SYSINIT(vnet_enc_init_proto, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
405 vnet_enc_init_proto, NULL);
406
407 static void
vnet_enc_uninit(const void * unused __unused)408 vnet_enc_uninit(const void *unused __unused)
409 {
410 KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
411
412 if_clone_detach(V_enc_cloner);
413 }
414 VNET_SYSUNINIT(vnet_enc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
415 vnet_enc_uninit, NULL);
416
417 /*
418 * The hhook consumer needs to go before ip[6]_destroy are called on
419 * SI_ORDER_THIRD.
420 */
421 static void
vnet_enc_uninit_hhook(const void * unused __unused)422 vnet_enc_uninit_hhook(const void *unused __unused)
423 {
424 KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
425
426 enc_remove_hhooks(V_enc_sc);
427 }
428 VNET_SYSUNINIT(vnet_enc_uninit_hhook, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
429 vnet_enc_uninit_hhook, NULL);
430
431 static int
enc_modevent(module_t mod,int type,void * data)432 enc_modevent(module_t mod, int type, void *data)
433 {
434
435 switch (type) {
436 case MOD_LOAD:
437 case MOD_UNLOAD:
438 break;
439 default:
440 return (EOPNOTSUPP);
441 }
442 return (0);
443 }
444
445 static moduledata_t enc_mod = {
446 "if_enc",
447 enc_modevent,
448 0
449 };
450
451 DECLARE_MODULE(if_enc, enc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
452 MODULE_VERSION(if_enc, 1);
453