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