1 /* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
4 * SPDX-License-Identifier: BSD-3-Clause
6 * Copyright (c) 2019 Gleb Smirnoff <glebius@FreeBSD.org>
7 * Copyright (c) 1996 Matthew R. Green
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/epoch.h>
38 #include <sys/errno.h>
40 #include <sys/malloc.h>
41 #include <sys/socket.h>
42 #include <sys/socketvar.h>
43 #include <sys/systm.h>
45 #include <sys/mutex.h>
47 #include <sys/queue.h>
48 #include <sys/ucred.h>
52 #include <net/if_var.h>
55 static MALLOC_DEFINE(M_PFIL, "pfil", "pfil(9) packet filter hooks");
57 static int pfil_ioctl(struct cdev *, u_long, caddr_t, int, struct thread *);
58 static struct cdevsw pfil_cdevsw = {
59 .d_ioctl = pfil_ioctl,
61 .d_version = D_VERSION,
63 static struct cdev *pfil_dev;
65 static struct mtx pfil_lock;
66 MTX_SYSINIT(pfil_mtxinit, &pfil_lock, "pfil(9) lock", MTX_DEF);
67 #define PFIL_LOCK() mtx_lock(&pfil_lock)
68 #define PFIL_UNLOCK() mtx_unlock(&pfil_lock)
69 #define PFIL_LOCK_ASSERT() mtx_assert(&pfil_lock, MA_OWNED)
72 pfil_mbuf_chk_t hook_mbuf_chk;
73 pfil_mem_chk_t hook_mem_chk;
77 enum pfil_types hook_type;
78 const char *hook_modname;
79 const char *hook_rulname;
80 LIST_ENTRY(pfil_hook) hook_list;
84 CK_STAILQ_ENTRY(pfil_link) link_chain;
85 pfil_mbuf_chk_t link_mbuf_chk;
86 pfil_mem_chk_t link_mem_chk;
89 struct pfil_hook *link_hook;
90 struct epoch_context link_epoch_ctx;
93 typedef CK_STAILQ_HEAD(pfil_chain, pfil_link) pfil_chain_t;
98 pfil_chain_t head_out;
100 enum pfil_types head_type;
101 LIST_ENTRY(pfil_head) head_list;
102 const char *head_name;
105 LIST_HEAD(pfilheadhead, pfil_head);
106 VNET_DEFINE_STATIC(struct pfilheadhead, pfil_head_list) =
107 LIST_HEAD_INITIALIZER(pfil_head_list);
108 #define V_pfil_head_list VNET(pfil_head_list)
110 LIST_HEAD(pfilhookhead, pfil_hook);
111 VNET_DEFINE_STATIC(struct pfilhookhead, pfil_hook_list) =
112 LIST_HEAD_INITIALIZER(pfil_hook_list);
113 #define V_pfil_hook_list VNET(pfil_hook_list)
115 static struct pfil_link *pfil_link_remove(pfil_chain_t *, pfil_hook_t );
116 static void pfil_link_free(epoch_context_t);
119 * To couple a filtering point that provides memory pointer with a filter that
120 * works on mbufs only.
122 static __noinline int
123 pfil_fake_mbuf(pfil_mbuf_chk_t func, void *mem, u_int len, struct ifnet *ifp,
124 int flags, void *ruleset, struct mbuf **mp)
129 (void)m_init(&m, M_NOWAIT, MT_DATA, M_NOFREE | M_PKTHDR);
130 m_extadd(&m, mem, len, NULL, NULL, NULL, 0, EXT_RXRING);
131 m.m_len = m.m_pkthdr.len = len;
134 rv = func(mp, ifp, flags, ruleset, NULL);
135 if (rv == PFIL_PASS && *mp != &m) {
137 * Firewalls that need pfil_fake_mbuf() most likely don't
138 * know they need return PFIL_REALLOCED.
146 static __always_inline int
147 pfil_mem_common(pfil_chain_t *pch, void *mem, u_int len, int flags,
148 struct ifnet *ifp, struct mbuf **m)
150 struct pfil_link *link;
152 bool realloc = false;
155 KASSERT(flags == PFIL_IN || flags == PFIL_OUT,
156 ("%s: unsupported flags %d", __func__, flags));
159 CK_STAILQ_FOREACH(link, pch, link_chain) {
160 if (__predict_true(link->link_mem_chk != NULL && !realloc))
161 rv = link->link_mem_chk(mem, len, flags, ifp,
162 link->link_ruleset, m);
164 rv = pfil_fake_mbuf(link->link_mbuf_chk, mem, len, ifp,
165 flags, link->link_ruleset, m);
167 rv = link->link_mbuf_chk(m, ifp, flags,
168 link->link_ruleset, NULL);
170 if (rv == PFIL_DROPPED || rv == PFIL_CONSUMED)
172 else if (rv == PFIL_REALLOCED)
175 if (realloc && rv == PFIL_PASS)
181 pfil_mem_in(struct pfil_head *head, void *mem, u_int len, struct ifnet *ifp,
185 return (pfil_mem_common(&head->head_in, mem, len, PFIL_IN, ifp, m));
189 pfil_mem_out(struct pfil_head *head, void *mem, u_int len, struct ifnet *ifp,
193 return (pfil_mem_common(&head->head_out, mem, len, PFIL_OUT, ifp, m));
196 static __always_inline int
197 pfil_mbuf_common(pfil_chain_t *pch, struct mbuf **m, struct ifnet *ifp,
198 int flags, struct inpcb *inp)
200 struct pfil_link *link;
204 KASSERT((flags & ~(PFIL_IN|PFIL_OUT|PFIL_FWD)) == 0,
205 ("%s: unsupported flags %#x", __func__, flags));
206 KASSERT((flags & ~PFIL_FWD) == PFIL_IN ||
207 (flags & ~PFIL_FWD) == PFIL_OUT,
208 ("%s: conflicting directions %#x", __func__, flags));
211 CK_STAILQ_FOREACH(link, pch, link_chain) {
212 rv = link->link_mbuf_chk(m, ifp, flags, link->link_ruleset,
214 if (rv == PFIL_DROPPED || rv == PFIL_CONSUMED)
221 pfil_mbuf_in(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
225 return (pfil_mbuf_common(&head->head_in, m, ifp, PFIL_IN, inp));
229 pfil_mbuf_out(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
233 return (pfil_mbuf_common(&head->head_out, m, ifp, PFIL_OUT, inp));
237 pfil_mbuf_fwd(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
241 return (pfil_mbuf_common(&head->head_out, m, ifp, PFIL_OUT | PFIL_FWD, inp));
245 * pfil_head_register() registers a pfil_head with the packet filter hook
249 pfil_head_register(struct pfil_head_args *pa)
251 struct pfil_head *head, *list;
253 MPASS(pa->pa_version == PFIL_VERSION);
255 head = malloc(sizeof(struct pfil_head), M_PFIL, M_WAITOK);
257 head->head_nhooksin = head->head_nhooksout = 0;
258 head->head_flags = pa->pa_flags;
259 head->head_type = pa->pa_type;
260 head->head_name = pa->pa_headname;
261 CK_STAILQ_INIT(&head->head_in);
262 CK_STAILQ_INIT(&head->head_out);
265 LIST_FOREACH(list, &V_pfil_head_list, head_list)
266 if (strcmp(pa->pa_headname, list->head_name) == 0) {
267 printf("pfil: duplicate head \"%s\"\n",
270 LIST_INSERT_HEAD(&V_pfil_head_list, head, head_list);
277 * pfil_head_unregister() removes a pfil_head from the packet filter hook
278 * mechanism. The producer of the hook promises that all outstanding
279 * invocations of the hook have completed before it unregisters the hook.
282 pfil_head_unregister(pfil_head_t ph)
284 struct pfil_link *link, *next;
287 LIST_REMOVE(ph, head_list);
289 CK_STAILQ_FOREACH_SAFE(link, &ph->head_in, link_chain, next) {
290 link->link_hook->hook_links--;
293 CK_STAILQ_FOREACH_SAFE(link, &ph->head_out, link_chain, next) {
294 link->link_hook->hook_links--;
301 pfil_add_hook(struct pfil_hook_args *pa)
303 struct pfil_hook *hook, *list;
305 MPASS(pa->pa_version == PFIL_VERSION);
307 hook = malloc(sizeof(struct pfil_hook), M_PFIL, M_WAITOK | M_ZERO);
308 hook->hook_mbuf_chk = pa->pa_mbuf_chk;
309 hook->hook_mem_chk = pa->pa_mem_chk;
310 hook->hook_ruleset = pa->pa_ruleset;
311 hook->hook_flags = pa->pa_flags;
312 hook->hook_type = pa->pa_type;
313 hook->hook_modname = pa->pa_modname;
314 hook->hook_rulname = pa->pa_rulname;
317 LIST_FOREACH(list, &V_pfil_hook_list, hook_list)
318 if (strcmp(pa->pa_modname, list->hook_modname) == 0 &&
319 strcmp(pa->pa_rulname, list->hook_rulname) == 0) {
320 printf("pfil: duplicate hook \"%s:%s\"\n",
321 pa->pa_modname, pa->pa_rulname);
323 LIST_INSERT_HEAD(&V_pfil_hook_list, hook, hook_list);
330 pfil_unlink(struct pfil_link_args *pa, pfil_head_t head, pfil_hook_t hook)
332 struct pfil_link *in, *out;
336 if (pa->pa_flags & PFIL_IN) {
337 in = pfil_link_remove(&head->head_in, hook);
339 head->head_nhooksin--;
344 if (pa->pa_flags & PFIL_OUT) {
345 out = pfil_link_remove(&head->head_out, hook);
347 head->head_nhooksout--;
355 NET_EPOCH_CALL(pfil_link_free, &in->link_epoch_ctx);
357 NET_EPOCH_CALL(pfil_link_free, &out->link_epoch_ctx);
359 if (in == NULL && out == NULL)
366 pfil_link(struct pfil_link_args *pa)
368 struct pfil_link *in, *out, *link;
369 struct pfil_head *head;
370 struct pfil_hook *hook;
373 MPASS(pa->pa_version == PFIL_VERSION);
375 if ((pa->pa_flags & (PFIL_IN | PFIL_UNLINK)) == PFIL_IN)
376 in = malloc(sizeof(*in), M_PFIL, M_WAITOK | M_ZERO);
379 if ((pa->pa_flags & (PFIL_OUT | PFIL_UNLINK)) == PFIL_OUT)
380 out = malloc(sizeof(*out), M_PFIL, M_WAITOK | M_ZERO);
385 if (pa->pa_flags & PFIL_HEADPTR)
388 LIST_FOREACH(head, &V_pfil_head_list, head_list)
389 if (strcmp(pa->pa_headname, head->head_name) == 0)
391 if (pa->pa_flags & PFIL_HOOKPTR)
394 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list)
395 if (strcmp(pa->pa_modname, hook->hook_modname) == 0 &&
396 strcmp(pa->pa_rulname, hook->hook_rulname) == 0)
398 if (head == NULL || hook == NULL) {
403 if (pa->pa_flags & PFIL_UNLINK)
404 return (pfil_unlink(pa, head, hook));
406 if (head->head_type != hook->hook_type ||
407 ((hook->hook_flags & pa->pa_flags) & ~head->head_flags)) {
412 if (pa->pa_flags & PFIL_IN)
413 CK_STAILQ_FOREACH(link, &head->head_in, link_chain)
414 if (link->link_hook == hook) {
418 if (pa->pa_flags & PFIL_OUT)
419 CK_STAILQ_FOREACH(link, &head->head_out, link_chain)
420 if (link->link_hook == hook) {
425 if (pa->pa_flags & PFIL_IN) {
426 in->link_hook = hook;
427 in->link_mbuf_chk = hook->hook_mbuf_chk;
428 in->link_mem_chk = hook->hook_mem_chk;
429 in->link_flags = hook->hook_flags;
430 in->link_ruleset = hook->hook_ruleset;
431 if (pa->pa_flags & PFIL_APPEND)
432 CK_STAILQ_INSERT_TAIL(&head->head_in, in, link_chain);
434 CK_STAILQ_INSERT_HEAD(&head->head_in, in, link_chain);
436 head->head_nhooksin++;
438 if (pa->pa_flags & PFIL_OUT) {
439 out->link_hook = hook;
440 out->link_mbuf_chk = hook->hook_mbuf_chk;
441 out->link_mem_chk = hook->hook_mem_chk;
442 out->link_flags = hook->hook_flags;
443 out->link_ruleset = hook->hook_ruleset;
444 if (pa->pa_flags & PFIL_APPEND)
445 CK_STAILQ_INSERT_HEAD(&head->head_out, out, link_chain);
447 CK_STAILQ_INSERT_TAIL(&head->head_out, out, link_chain);
449 head->head_nhooksout++;
463 pfil_link_free(epoch_context_t ctx)
465 struct pfil_link *link;
467 link = __containerof(ctx, struct pfil_link, link_epoch_ctx);
472 * pfil_remove_hook removes a filter from all filtering points.
475 pfil_remove_hook(pfil_hook_t hook)
477 struct pfil_head *head;
478 struct pfil_link *in, *out;
481 LIST_FOREACH(head, &V_pfil_head_list, head_list) {
483 in = pfil_link_remove(&head->head_in, hook);
485 head->head_nhooksin--;
487 NET_EPOCH_CALL(pfil_link_free, &in->link_epoch_ctx);
489 out = pfil_link_remove(&head->head_out, hook);
491 head->head_nhooksout--;
493 NET_EPOCH_CALL(pfil_link_free, &out->link_epoch_ctx);
495 if (in != NULL || out != NULL)
496 /* What if some stupid admin put same filter twice? */
499 LIST_REMOVE(hook, hook_list);
501 MPASS(hook->hook_links == 0);
506 * Internal: Remove a pfil hook from a hook chain.
508 static struct pfil_link *
509 pfil_link_remove(pfil_chain_t *chain, pfil_hook_t hook)
511 struct pfil_link *link;
515 CK_STAILQ_FOREACH(link, chain, link_chain)
516 if (link->link_hook == hook) {
517 CK_STAILQ_REMOVE(chain, link, pfil_link, link_chain);
525 pfil_init(const void *unused __unused)
527 struct make_dev_args args;
528 int error __diagused;
530 make_dev_args_init(&args);
531 args.mda_flags = MAKEDEV_WAITOK | MAKEDEV_CHECKNAME;
532 args.mda_devsw = &pfil_cdevsw;
533 args.mda_uid = UID_ROOT;
534 args.mda_gid = GID_WHEEL;
535 args.mda_mode = 0600;
536 error = make_dev_s(&args, &pfil_dev, PFILDEV);
537 KASSERT(error == 0, ("%s: failed to create dev: %d", __func__, error));
540 * Make sure the pfil bits are first before any possible subsystem which
541 * might piggyback on the SI_SUB_PROTO_PFIL.
543 SYSINIT(pfil_init, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST, pfil_init, NULL);
546 * User control interface.
548 static int pfilioc_listheads(struct pfilioc_list *);
549 static int pfilioc_listhooks(struct pfilioc_list *);
550 static int pfilioc_link(struct pfilioc_link *);
553 pfil_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
558 CURVNET_SET(TD_TO_VNET(td));
561 case PFILIOC_LISTHEADS:
562 error = pfilioc_listheads((struct pfilioc_list *)addr);
564 case PFILIOC_LISTHOOKS:
565 error = pfilioc_listhooks((struct pfilioc_list *)addr);
568 error = pfilioc_link((struct pfilioc_link *)addr);
579 pfilioc_listheads(struct pfilioc_list *req)
581 struct pfil_head *head;
582 struct pfil_link *link;
583 struct pfilioc_head *iohead;
584 struct pfilioc_hook *iohook;
585 u_int nheads, nhooks, hd, hk;
591 LIST_FOREACH(head, &V_pfil_head_list, head_list) {
593 nhooks += head->head_nhooksin + head->head_nhooksout;
597 if (req->pio_nheads < nheads || req->pio_nhooks < nhooks) {
598 req->pio_nheads = nheads;
599 req->pio_nhooks = nhooks;
603 iohead = malloc(sizeof(*iohead) * nheads, M_TEMP, M_WAITOK);
604 iohook = malloc(sizeof(*iohook) * nhooks, M_TEMP, M_WAITOK);
608 LIST_FOREACH(head, &V_pfil_head_list, head_list) {
609 if (hd + 1 > nheads ||
610 hk + head->head_nhooksin + head->head_nhooksout > nhooks) {
611 /* Configuration changed during malloc(). */
612 free(iohead, M_TEMP);
613 free(iohook, M_TEMP);
616 strlcpy(iohead[hd].pio_name, head->head_name,
617 sizeof(iohead[0].pio_name));
618 iohead[hd].pio_nhooksin = head->head_nhooksin;
619 iohead[hd].pio_nhooksout = head->head_nhooksout;
620 iohead[hd].pio_type = head->head_type;
621 CK_STAILQ_FOREACH(link, &head->head_in, link_chain) {
622 strlcpy(iohook[hk].pio_module,
623 link->link_hook->hook_modname,
624 sizeof(iohook[0].pio_module));
625 strlcpy(iohook[hk].pio_ruleset,
626 link->link_hook->hook_rulname,
627 sizeof(iohook[0].pio_ruleset));
630 CK_STAILQ_FOREACH(link, &head->head_out, link_chain) {
631 strlcpy(iohook[hk].pio_module,
632 link->link_hook->hook_modname,
633 sizeof(iohook[0].pio_module));
634 strlcpy(iohook[hk].pio_ruleset,
635 link->link_hook->hook_rulname,
636 sizeof(iohook[0].pio_ruleset));
643 error = copyout(iohead, req->pio_heads,
644 sizeof(*iohead) * min(hd, req->pio_nheads));
646 error = copyout(iohook, req->pio_hooks,
647 sizeof(*iohook) * min(req->pio_nhooks, hk));
649 req->pio_nheads = hd;
650 req->pio_nhooks = hk;
652 free(iohead, M_TEMP);
653 free(iohook, M_TEMP);
659 pfilioc_listhooks(struct pfilioc_list *req)
661 struct pfil_hook *hook;
662 struct pfilioc_hook *iohook;
669 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list)
673 if (req->pio_nhooks < nhooks) {
674 req->pio_nhooks = nhooks;
678 iohook = malloc(sizeof(*iohook) * nhooks, M_TEMP, M_WAITOK);
682 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list) {
683 if (hk + 1 > nhooks) {
684 /* Configuration changed during malloc(). */
685 free(iohook, M_TEMP);
688 strlcpy(iohook[hk].pio_module, hook->hook_modname,
689 sizeof(iohook[0].pio_module));
690 strlcpy(iohook[hk].pio_ruleset, hook->hook_rulname,
691 sizeof(iohook[0].pio_ruleset));
692 iohook[hk].pio_type = hook->hook_type;
693 iohook[hk].pio_flags = hook->hook_flags;
698 error = copyout(iohook, req->pio_hooks,
699 sizeof(*iohook) * min(req->pio_nhooks, hk));
700 req->pio_nhooks = hk;
701 free(iohook, M_TEMP);
707 pfilioc_link(struct pfilioc_link *req)
709 struct pfil_link_args args;
711 if (req->pio_flags & ~(PFIL_IN | PFIL_OUT | PFIL_UNLINK | PFIL_APPEND))
714 args.pa_version = PFIL_VERSION;
715 args.pa_flags = req->pio_flags;
716 args.pa_headname = req->pio_name;
717 args.pa_modname = req->pio_module;
718 args.pa_rulname = req->pio_ruleset;
720 return (pfil_link(&args));