2 /* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
5 * SPDX-License-Identifier: BSD-3-Clause
7 * Copyright (c) 2019 Gleb Smirnoff <glebius@FreeBSD.org>
8 * Copyright (c) 1996 Matthew R. Green
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/epoch.h>
39 #include <sys/errno.h>
41 #include <sys/malloc.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/systm.h>
46 #include <sys/mutex.h>
48 #include <sys/queue.h>
49 #include <sys/ucred.h>
53 #include <net/if_var.h>
56 static MALLOC_DEFINE(M_PFIL, "pfil", "pfil(9) packet filter hooks");
58 static int pfil_ioctl(struct cdev *, u_long, caddr_t, int, struct thread *);
59 static struct cdevsw pfil_cdevsw = {
60 .d_ioctl = pfil_ioctl,
62 .d_version = D_VERSION,
64 static struct cdev *pfil_dev;
66 static struct mtx pfil_lock;
67 MTX_SYSINIT(pfil_mtxinit, &pfil_lock, "pfil(9) lock", MTX_DEF);
68 #define PFIL_LOCK() mtx_lock(&pfil_lock)
69 #define PFIL_UNLOCK() mtx_unlock(&pfil_lock)
70 #define PFIL_LOCK_ASSERT() mtx_assert(&pfil_lock, MA_OWNED)
73 pfil_mbuf_chk_t hook_mbuf_chk;
74 pfil_mem_chk_t hook_mem_chk;
78 enum pfil_types hook_type;
79 const char *hook_modname;
80 const char *hook_rulname;
81 LIST_ENTRY(pfil_hook) hook_list;
85 CK_STAILQ_ENTRY(pfil_link) link_chain;
86 pfil_mbuf_chk_t link_mbuf_chk;
87 pfil_mem_chk_t link_mem_chk;
90 struct pfil_hook *link_hook;
91 struct epoch_context link_epoch_ctx;
94 typedef CK_STAILQ_HEAD(pfil_chain, pfil_link) pfil_chain_t;
99 pfil_chain_t head_out;
101 enum pfil_types head_type;
102 LIST_ENTRY(pfil_head) head_list;
103 const char *head_name;
106 LIST_HEAD(pfilheadhead, pfil_head);
107 VNET_DEFINE_STATIC(struct pfilheadhead, pfil_head_list) =
108 LIST_HEAD_INITIALIZER(pfil_head_list);
109 #define V_pfil_head_list VNET(pfil_head_list)
111 LIST_HEAD(pfilhookhead, pfil_hook);
112 VNET_DEFINE_STATIC(struct pfilhookhead, pfil_hook_list) =
113 LIST_HEAD_INITIALIZER(pfil_hook_list);
114 #define V_pfil_hook_list VNET(pfil_hook_list)
116 static struct pfil_link *pfil_link_remove(pfil_chain_t *, pfil_hook_t );
117 static void pfil_link_free(epoch_context_t);
120 * To couple a filtering point that provides memory pointer with a filter that
121 * works on mbufs only.
123 static __noinline int
124 pfil_fake_mbuf(pfil_mbuf_chk_t func, void *mem, u_int len, struct ifnet *ifp,
125 int flags, void *ruleset, struct mbuf **mp)
130 (void)m_init(&m, M_NOWAIT, MT_DATA, M_NOFREE | M_PKTHDR);
131 m_extadd(&m, mem, len, NULL, NULL, NULL, 0, EXT_RXRING);
132 m.m_len = m.m_pkthdr.len = len;
135 rv = func(mp, ifp, flags, ruleset, NULL);
136 if (rv == PFIL_PASS && *mp != &m) {
138 * Firewalls that need pfil_fake_mbuf() most likely don't
139 * know they need return PFIL_REALLOCED.
147 static __always_inline int
148 pfil_mem_common(pfil_chain_t *pch, void *mem, u_int len, int flags,
149 struct ifnet *ifp, struct mbuf **m)
151 struct pfil_link *link;
153 bool realloc = false;
156 KASSERT(flags == PFIL_IN || flags == PFIL_OUT,
157 ("%s: unsupported flags %d", __func__, flags));
160 CK_STAILQ_FOREACH(link, pch, link_chain) {
161 if (__predict_true(link->link_mem_chk != NULL && !realloc))
162 rv = link->link_mem_chk(mem, len, flags, ifp,
163 link->link_ruleset, m);
165 rv = pfil_fake_mbuf(link->link_mbuf_chk, mem, len, ifp,
166 flags, link->link_ruleset, m);
168 rv = link->link_mbuf_chk(m, ifp, flags,
169 link->link_ruleset, NULL);
171 if (rv == PFIL_DROPPED || rv == PFIL_CONSUMED)
173 else if (rv == PFIL_REALLOCED)
176 if (realloc && rv == PFIL_PASS)
182 pfil_mem_in(struct pfil_head *head, void *mem, u_int len, struct ifnet *ifp,
186 return (pfil_mem_common(&head->head_in, mem, len, PFIL_IN, ifp, m));
190 pfil_mem_out(struct pfil_head *head, void *mem, u_int len, struct ifnet *ifp,
194 return (pfil_mem_common(&head->head_out, mem, len, PFIL_OUT, ifp, m));
197 static __always_inline int
198 pfil_mbuf_common(pfil_chain_t *pch, struct mbuf **m, struct ifnet *ifp,
199 int flags, struct inpcb *inp)
201 struct pfil_link *link;
205 KASSERT((flags & ~(PFIL_IN|PFIL_OUT|PFIL_FWD)) == 0,
206 ("%s: unsupported flags %#x", __func__, flags));
207 KASSERT((flags & ~PFIL_FWD) == PFIL_IN ||
208 (flags & ~PFIL_FWD) == PFIL_OUT,
209 ("%s: conflicting directions %#x", __func__, flags));
212 CK_STAILQ_FOREACH(link, pch, link_chain) {
213 rv = link->link_mbuf_chk(m, ifp, flags, link->link_ruleset,
215 if (rv == PFIL_DROPPED || rv == PFIL_CONSUMED)
222 pfil_mbuf_in(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
226 return (pfil_mbuf_common(&head->head_in, m, ifp, PFIL_IN, inp));
230 pfil_mbuf_out(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
234 return (pfil_mbuf_common(&head->head_out, m, ifp, PFIL_OUT, inp));
238 pfil_mbuf_fwd(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
242 return (pfil_mbuf_common(&head->head_out, m, ifp, PFIL_OUT | PFIL_FWD, inp));
246 * pfil_head_register() registers a pfil_head with the packet filter hook
250 pfil_head_register(struct pfil_head_args *pa)
252 struct pfil_head *head, *list;
254 MPASS(pa->pa_version == PFIL_VERSION);
256 head = malloc(sizeof(struct pfil_head), M_PFIL, M_WAITOK);
258 head->head_nhooksin = head->head_nhooksout = 0;
259 head->head_flags = pa->pa_flags;
260 head->head_type = pa->pa_type;
261 head->head_name = pa->pa_headname;
262 CK_STAILQ_INIT(&head->head_in);
263 CK_STAILQ_INIT(&head->head_out);
266 LIST_FOREACH(list, &V_pfil_head_list, head_list)
267 if (strcmp(pa->pa_headname, list->head_name) == 0) {
268 printf("pfil: duplicate head \"%s\"\n",
271 LIST_INSERT_HEAD(&V_pfil_head_list, head, head_list);
278 * pfil_head_unregister() removes a pfil_head from the packet filter hook
279 * mechanism. The producer of the hook promises that all outstanding
280 * invocations of the hook have completed before it unregisters the hook.
283 pfil_head_unregister(pfil_head_t ph)
285 struct pfil_link *link, *next;
288 LIST_REMOVE(ph, head_list);
290 CK_STAILQ_FOREACH_SAFE(link, &ph->head_in, link_chain, next) {
291 link->link_hook->hook_links--;
294 CK_STAILQ_FOREACH_SAFE(link, &ph->head_out, link_chain, next) {
295 link->link_hook->hook_links--;
302 pfil_add_hook(struct pfil_hook_args *pa)
304 struct pfil_hook *hook, *list;
306 MPASS(pa->pa_version == PFIL_VERSION);
308 hook = malloc(sizeof(struct pfil_hook), M_PFIL, M_WAITOK | M_ZERO);
309 hook->hook_mbuf_chk = pa->pa_mbuf_chk;
310 hook->hook_mem_chk = pa->pa_mem_chk;
311 hook->hook_ruleset = pa->pa_ruleset;
312 hook->hook_flags = pa->pa_flags;
313 hook->hook_type = pa->pa_type;
314 hook->hook_modname = pa->pa_modname;
315 hook->hook_rulname = pa->pa_rulname;
318 LIST_FOREACH(list, &V_pfil_hook_list, hook_list)
319 if (strcmp(pa->pa_modname, list->hook_modname) == 0 &&
320 strcmp(pa->pa_rulname, list->hook_rulname) == 0) {
321 printf("pfil: duplicate hook \"%s:%s\"\n",
322 pa->pa_modname, pa->pa_rulname);
324 LIST_INSERT_HEAD(&V_pfil_hook_list, hook, hook_list);
331 pfil_unlink(struct pfil_link_args *pa, pfil_head_t head, pfil_hook_t hook)
333 struct pfil_link *in, *out;
337 if (pa->pa_flags & PFIL_IN) {
338 in = pfil_link_remove(&head->head_in, hook);
340 head->head_nhooksin--;
345 if (pa->pa_flags & PFIL_OUT) {
346 out = pfil_link_remove(&head->head_out, hook);
348 head->head_nhooksout--;
356 NET_EPOCH_CALL(pfil_link_free, &in->link_epoch_ctx);
358 NET_EPOCH_CALL(pfil_link_free, &out->link_epoch_ctx);
360 if (in == NULL && out == NULL)
367 pfil_link(struct pfil_link_args *pa)
369 struct pfil_link *in, *out, *link;
370 struct pfil_head *head;
371 struct pfil_hook *hook;
374 MPASS(pa->pa_version == PFIL_VERSION);
376 if ((pa->pa_flags & (PFIL_IN | PFIL_UNLINK)) == PFIL_IN)
377 in = malloc(sizeof(*in), M_PFIL, M_WAITOK | M_ZERO);
380 if ((pa->pa_flags & (PFIL_OUT | PFIL_UNLINK)) == PFIL_OUT)
381 out = malloc(sizeof(*out), M_PFIL, M_WAITOK | M_ZERO);
386 if (pa->pa_flags & PFIL_HEADPTR)
389 LIST_FOREACH(head, &V_pfil_head_list, head_list)
390 if (strcmp(pa->pa_headname, head->head_name) == 0)
392 if (pa->pa_flags & PFIL_HOOKPTR)
395 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list)
396 if (strcmp(pa->pa_modname, hook->hook_modname) == 0 &&
397 strcmp(pa->pa_rulname, hook->hook_rulname) == 0)
399 if (head == NULL || hook == NULL) {
404 if (pa->pa_flags & PFIL_UNLINK)
405 return (pfil_unlink(pa, head, hook));
407 if (head->head_type != hook->hook_type ||
408 ((hook->hook_flags & pa->pa_flags) & ~head->head_flags)) {
413 if (pa->pa_flags & PFIL_IN)
414 CK_STAILQ_FOREACH(link, &head->head_in, link_chain)
415 if (link->link_hook == hook) {
419 if (pa->pa_flags & PFIL_OUT)
420 CK_STAILQ_FOREACH(link, &head->head_out, link_chain)
421 if (link->link_hook == hook) {
426 if (pa->pa_flags & PFIL_IN) {
427 in->link_hook = hook;
428 in->link_mbuf_chk = hook->hook_mbuf_chk;
429 in->link_mem_chk = hook->hook_mem_chk;
430 in->link_flags = hook->hook_flags;
431 in->link_ruleset = hook->hook_ruleset;
432 if (pa->pa_flags & PFIL_APPEND)
433 CK_STAILQ_INSERT_TAIL(&head->head_in, in, link_chain);
435 CK_STAILQ_INSERT_HEAD(&head->head_in, in, link_chain);
437 head->head_nhooksin++;
439 if (pa->pa_flags & PFIL_OUT) {
440 out->link_hook = hook;
441 out->link_mbuf_chk = hook->hook_mbuf_chk;
442 out->link_mem_chk = hook->hook_mem_chk;
443 out->link_flags = hook->hook_flags;
444 out->link_ruleset = hook->hook_ruleset;
445 if (pa->pa_flags & PFIL_APPEND)
446 CK_STAILQ_INSERT_HEAD(&head->head_out, out, link_chain);
448 CK_STAILQ_INSERT_TAIL(&head->head_out, out, link_chain);
450 head->head_nhooksout++;
464 pfil_link_free(epoch_context_t ctx)
466 struct pfil_link *link;
468 link = __containerof(ctx, struct pfil_link, link_epoch_ctx);
473 * pfil_remove_hook removes a filter from all filtering points.
476 pfil_remove_hook(pfil_hook_t hook)
478 struct pfil_head *head;
479 struct pfil_link *in, *out;
482 LIST_FOREACH(head, &V_pfil_head_list, head_list) {
484 in = pfil_link_remove(&head->head_in, hook);
486 head->head_nhooksin--;
488 NET_EPOCH_CALL(pfil_link_free, &in->link_epoch_ctx);
490 out = pfil_link_remove(&head->head_out, hook);
492 head->head_nhooksout--;
494 NET_EPOCH_CALL(pfil_link_free, &out->link_epoch_ctx);
496 if (in != NULL || out != NULL)
497 /* What if some stupid admin put same filter twice? */
500 LIST_REMOVE(hook, hook_list);
502 MPASS(hook->hook_links == 0);
507 * Internal: Remove a pfil hook from a hook chain.
509 static struct pfil_link *
510 pfil_link_remove(pfil_chain_t *chain, pfil_hook_t hook)
512 struct pfil_link *link;
516 CK_STAILQ_FOREACH(link, chain, link_chain)
517 if (link->link_hook == hook) {
518 CK_STAILQ_REMOVE(chain, link, pfil_link, link_chain);
526 pfil_init(const void *unused __unused)
528 struct make_dev_args args;
529 int error __diagused;
531 make_dev_args_init(&args);
532 args.mda_flags = MAKEDEV_WAITOK | MAKEDEV_CHECKNAME;
533 args.mda_devsw = &pfil_cdevsw;
534 args.mda_uid = UID_ROOT;
535 args.mda_gid = GID_WHEEL;
536 args.mda_mode = 0600;
537 error = make_dev_s(&args, &pfil_dev, PFILDEV);
538 KASSERT(error == 0, ("%s: failed to create dev: %d", __func__, error));
541 * Make sure the pfil bits are first before any possible subsystem which
542 * might piggyback on the SI_SUB_PROTO_PFIL.
544 SYSINIT(pfil_init, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST, pfil_init, NULL);
547 * User control interface.
549 static int pfilioc_listheads(struct pfilioc_list *);
550 static int pfilioc_listhooks(struct pfilioc_list *);
551 static int pfilioc_link(struct pfilioc_link *);
554 pfil_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
559 CURVNET_SET(TD_TO_VNET(td));
562 case PFILIOC_LISTHEADS:
563 error = pfilioc_listheads((struct pfilioc_list *)addr);
565 case PFILIOC_LISTHOOKS:
566 error = pfilioc_listhooks((struct pfilioc_list *)addr);
569 error = pfilioc_link((struct pfilioc_link *)addr);
580 pfilioc_listheads(struct pfilioc_list *req)
582 struct pfil_head *head;
583 struct pfil_link *link;
584 struct pfilioc_head *iohead;
585 struct pfilioc_hook *iohook;
586 u_int nheads, nhooks, hd, hk;
592 LIST_FOREACH(head, &V_pfil_head_list, head_list) {
594 nhooks += head->head_nhooksin + head->head_nhooksout;
598 if (req->pio_nheads < nheads || req->pio_nhooks < nhooks) {
599 req->pio_nheads = nheads;
600 req->pio_nhooks = nhooks;
604 iohead = malloc(sizeof(*iohead) * nheads, M_TEMP, M_WAITOK);
605 iohook = malloc(sizeof(*iohook) * nhooks, M_TEMP, M_WAITOK);
609 LIST_FOREACH(head, &V_pfil_head_list, head_list) {
610 if (hd + 1 > nheads ||
611 hk + head->head_nhooksin + head->head_nhooksout > nhooks) {
612 /* Configuration changed during malloc(). */
613 free(iohead, M_TEMP);
614 free(iohook, M_TEMP);
617 strlcpy(iohead[hd].pio_name, head->head_name,
618 sizeof(iohead[0].pio_name));
619 iohead[hd].pio_nhooksin = head->head_nhooksin;
620 iohead[hd].pio_nhooksout = head->head_nhooksout;
621 iohead[hd].pio_type = head->head_type;
622 CK_STAILQ_FOREACH(link, &head->head_in, link_chain) {
623 strlcpy(iohook[hk].pio_module,
624 link->link_hook->hook_modname,
625 sizeof(iohook[0].pio_module));
626 strlcpy(iohook[hk].pio_ruleset,
627 link->link_hook->hook_rulname,
628 sizeof(iohook[0].pio_ruleset));
631 CK_STAILQ_FOREACH(link, &head->head_out, link_chain) {
632 strlcpy(iohook[hk].pio_module,
633 link->link_hook->hook_modname,
634 sizeof(iohook[0].pio_module));
635 strlcpy(iohook[hk].pio_ruleset,
636 link->link_hook->hook_rulname,
637 sizeof(iohook[0].pio_ruleset));
644 error = copyout(iohead, req->pio_heads,
645 sizeof(*iohead) * min(hd, req->pio_nheads));
647 error = copyout(iohook, req->pio_hooks,
648 sizeof(*iohook) * min(req->pio_nhooks, hk));
650 req->pio_nheads = hd;
651 req->pio_nhooks = hk;
653 free(iohead, M_TEMP);
654 free(iohook, M_TEMP);
660 pfilioc_listhooks(struct pfilioc_list *req)
662 struct pfil_hook *hook;
663 struct pfilioc_hook *iohook;
670 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list)
674 if (req->pio_nhooks < nhooks) {
675 req->pio_nhooks = nhooks;
679 iohook = malloc(sizeof(*iohook) * nhooks, M_TEMP, M_WAITOK);
683 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list) {
684 if (hk + 1 > nhooks) {
685 /* Configuration changed during malloc(). */
686 free(iohook, M_TEMP);
689 strlcpy(iohook[hk].pio_module, hook->hook_modname,
690 sizeof(iohook[0].pio_module));
691 strlcpy(iohook[hk].pio_ruleset, hook->hook_rulname,
692 sizeof(iohook[0].pio_ruleset));
693 iohook[hk].pio_type = hook->hook_type;
694 iohook[hk].pio_flags = hook->hook_flags;
699 error = copyout(iohook, req->pio_hooks,
700 sizeof(*iohook) * min(req->pio_nhooks, hk));
701 req->pio_nhooks = hk;
702 free(iohook, M_TEMP);
708 pfilioc_link(struct pfilioc_link *req)
710 struct pfil_link_args args;
712 if (req->pio_flags & ~(PFIL_IN | PFIL_OUT | PFIL_UNLINK | PFIL_APPEND))
715 args.pa_version = PFIL_VERSION;
716 args.pa_flags = req->pio_flags;
717 args.pa_headname = req->pio_name;
718 args.pa_modname = req->pio_module;
719 args.pa_rulname = req->pio_ruleset;
721 return (pfil_link(&args));