pf_ruleset.c

/*	$OpenBSD: pf_ruleset.c,v 1.18 2018/12/27 16:54:01 kn Exp $ */

/*
 * Copyright (c) 2001 Daniel Hartmeier
 * Copyright (c) 2002,2003 Henning Brauer
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *    - Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    - Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Effort sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F30602-01-2-0537.
 *
 */

#include <sys/param.h>
#include <sys/socket.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <sys/mbuf.h>
#endif /* _KERNEL */
#include <sys/syslog.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>

#include <net/if.h>
#include <net/pfvar.h>

#ifdef INET6
#include <netinet/ip6.h>
#endif /* INET6 */


#ifdef _KERNEL
#define rs_malloc(x)		malloc(x, M_TEMP, M_WAITOK|M_CANFAIL|M_ZERO)
#define rs_free(x, siz)		free(x, M_TEMP, siz)

#else	/* !_KERNEL */
/* Userland equivalents so we can lend code to pfctl et al. */

#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define rs_malloc(x)		 calloc(1, x)
#define rs_free(x, siz)		 freezero(x, siz)

#ifdef PFDEBUG
#include <sys/stdarg.h>	/* for DPFPRINTF() */
#endif	/* PFDEBUG */
#endif /* _KERNEL */


struct pf_anchor_global	 pf_anchors;
struct pf_anchor	 pf_main_anchor;

static __inline int pf_anchor_compare(struct pf_anchor *, struct pf_anchor *);

RB_GENERATE(pf_anchor_global, pf_anchor, entry_global, pf_anchor_compare);
RB_GENERATE(pf_anchor_node, pf_anchor, entry_node, pf_anchor_compare);

static __inline int
pf_anchor_compare(struct pf_anchor *a, struct pf_anchor *b)
{
	int c = strcmp(a->path, b->path);

	return (c ? (c < 0 ? -1 : 1) : 0);
}

void
pf_init_ruleset(struct pf_ruleset *ruleset)
{
	memset(ruleset, 0, sizeof(struct pf_ruleset));
	TAILQ_INIT(&ruleset->rules.queues[0]);
	TAILQ_INIT(&ruleset->rules.queues[1]);
	ruleset->rules.active.ptr = &ruleset->rules.queues[0];
	ruleset->rules.inactive.ptr = &ruleset->rules.queues[1];
}

struct pf_anchor *
pf_find_anchor(const char *path)
{
	struct pf_anchor	*key, *found;

	key = rs_malloc(sizeof(*key));
	if (key == NULL)
		return (NULL);
	strlcpy(key->path, path, sizeof(key->path));
	found = RB_FIND(pf_anchor_global, &pf_anchors, key);
	rs_free(key, sizeof(*key));
	return (found);
}

struct pf_ruleset *
pf_find_ruleset(const char *path)
{
	struct pf_anchor	*anchor;

	while (*path == '/')
		path++;
	if (!*path)
		return (&pf_main_ruleset);
	anchor = pf_find_anchor(path);
	if (anchor == NULL)
		return (NULL);
	else
		return (&anchor->ruleset);
}

struct pf_ruleset *
pf_get_leaf_ruleset(char *path, char **path_remainder)
{
	struct pf_ruleset	*ruleset;
	char			*leaf, *p;
	int			 i = 0;

	p = path;
	while (*p == '/')
		p++;

	ruleset = pf_find_ruleset(p);
	leaf = p;
	while (ruleset == NULL) {
		leaf = strrchr(p, '/');
		if (leaf != NULL) {
			*leaf = '\0';
			i++;
			ruleset = pf_find_ruleset(p);
		} else {
			leaf = path;
			/*
			 * if no path component exists, then main ruleset is
			 * our parent.
			 */
			ruleset = &pf_main_ruleset;
		}
	}

	if (path_remainder != NULL)
		*path_remainder = leaf;

	/* restore slashes in path.  */
	while (i != 0) {
		while (*leaf != '\0')
			leaf++;
		*leaf = '/';
		i--;
	}

	return (ruleset);
}

struct pf_anchor *
pf_create_anchor(struct pf_anchor *parent, const char *aname)
{
	struct pf_anchor	*anchor, *dup;

	if (!*aname || (strlen(aname) >= PF_ANCHOR_NAME_SIZE) ||
	    ((parent != NULL) && (strlen(parent->path) >= PF_ANCHOR_MAXPATH)))
		return (NULL);

	anchor = rs_malloc(sizeof(*anchor));
	if (anchor == NULL)
		return (NULL);

	RB_INIT(&anchor->children);
	strlcpy(anchor->name, aname, sizeof(anchor->name));
	if (parent != NULL) {
		/*
		 * Make sure path for levels 2, 3, ... is terminated by '/':
		 *	1/2/3/...
		 */
		strlcpy(anchor->path, parent->path, sizeof(anchor->path));
		strlcat(anchor->path, "/", sizeof(anchor->path));
	}
	strlcat(anchor->path, anchor->name, sizeof(anchor->path));

	if ((dup = RB_INSERT(pf_anchor_global, &pf_anchors, anchor)) != NULL) {
		DPFPRINTF(LOG_NOTICE,
		    "%s: RB_INSERT to global '%s' '%s' collides with '%s' '%s'",
		    __func__, anchor->path, anchor->name, dup->path, dup->name);
		rs_free(anchor, sizeof(*anchor));
		return (NULL);
	}

	if (parent != NULL) {
		anchor->parent = parent;
		dup = RB_INSERT(pf_anchor_node, &parent->children, anchor);
		if (dup != NULL) {
			DPFPRINTF(LOG_NOTICE,
			    "%s: RB_INSERT to parent '%s' '%s' collides with "
			    "'%s' '%s'", __func__, anchor->path, anchor->name,
			    dup->path, dup->name);
			RB_REMOVE(pf_anchor_global, &pf_anchors,
			    anchor);
			rs_free(anchor, sizeof(*anchor));
			return (NULL);
		}
	}

	pf_init_ruleset(&anchor->ruleset);
	anchor->ruleset.anchor = anchor;

	return (anchor);
}

struct pf_ruleset *
pf_find_or_create_ruleset(const char *path)
{
	char			*p, *aname, *r;
	struct pf_ruleset	*ruleset;
	struct pf_anchor	*anchor;

	if (path[0] == 0)
		return (&pf_main_ruleset);

	while (*path == '/')
		path++;

	ruleset = pf_find_ruleset(path);
	if (ruleset != NULL)
		return (ruleset);

	p = rs_malloc(MAXPATHLEN);
	if (p == NULL)
		return (NULL);
	strlcpy(p, path, MAXPATHLEN);

	ruleset = pf_get_leaf_ruleset(p, &aname);
	anchor = ruleset->anchor;

	while (*aname == '/')
		aname++;
	/*
	 * aname is a path remainder, which contains nodes we must create.  We
	 * process the aname path from left to right, effectively descending
	 * from parents to children.
	 */
	while ((r = strchr(aname, '/')) != NULL || *aname) {
		if (r != NULL)
			*r = 0;

		anchor = pf_create_anchor(anchor, aname);
		if (anchor == NULL) {
			rs_free(p, MAXPATHLEN);
			return (NULL);
		}

		if (r == NULL)
			break;
		else
			aname = r + 1;
	}

	rs_free(p, MAXPATHLEN);
	return (&anchor->ruleset);
}

void
pf_remove_if_empty_ruleset(struct pf_ruleset *ruleset)
{
	struct pf_anchor	*parent;

	while (ruleset != NULL) {
		if (ruleset == &pf_main_ruleset ||
		    !RB_EMPTY(&ruleset->anchor->children) ||
		    ruleset->anchor->refcnt > 0 || ruleset->tables > 0 ||
		    ruleset->topen)
			return;
		if (!TAILQ_EMPTY(ruleset->rules.active.ptr) ||
		    !TAILQ_EMPTY(ruleset->rules.inactive.ptr) ||
		    ruleset->rules.inactive.open)
			return;
		RB_REMOVE(pf_anchor_global, &pf_anchors, ruleset->anchor);
		if ((parent = ruleset->anchor->parent) != NULL)
			RB_REMOVE(pf_anchor_node, &parent->children,
			    ruleset->anchor);
		rs_free(ruleset->anchor, sizeof(*(ruleset->anchor)));
		if (parent == NULL)
			return;
		ruleset = &parent->ruleset;
	}
}

int
pf_anchor_setup(struct pf_rule *r, const struct pf_ruleset *s,
    const char *name)
{
	char			*p, *path;
	struct pf_ruleset	*ruleset;

	r->anchor = NULL;
	r->anchor_relative = 0;
	r->anchor_wildcard = 0;
	if (!name[0])
		return (0);
	path = rs_malloc(MAXPATHLEN);
	if (path == NULL)
		return (1);
	if (name[0] == '/')
		strlcpy(path, name + 1, MAXPATHLEN);
	else {
		/* relative path */
		r->anchor_relative = 1;
		if (s->anchor == NULL || !s->anchor->path[0])
			path[0] = 0;
		else
			strlcpy(path, s->anchor->path, MAXPATHLEN);
		while (name[0] == '.' && name[1] == '.' && name[2] == '/') {
			if (!path[0]) {
				DPFPRINTF(LOG_NOTICE,
				    "pf_anchor_setup: .. beyond root");
				rs_free(path, MAXPATHLEN);
				return (1);
			}
			if ((p = strrchr(path, '/')) != NULL)
				*p = 0;
			else
				path[0] = 0;
			r->anchor_relative++;
			name += 3;
		}
		if (path[0])
			strlcat(path, "/", MAXPATHLEN);
		strlcat(path, name, MAXPATHLEN);
	}
	if ((p = strrchr(path, '/')) != NULL && !strcmp(p, "/*")) {
		r->anchor_wildcard = 1;
		*p = 0;
	}
	ruleset = pf_find_or_create_ruleset(path);
	rs_free(path, MAXPATHLEN);
	if (ruleset == NULL || ruleset == &pf_main_ruleset) {
		DPFPRINTF(LOG_NOTICE,
		    "pf_anchor_setup: ruleset");
		return (1);
	}
	r->anchor = ruleset->anchor;
	r->anchor->refcnt++;
	return (0);
}

int
pf_anchor_copyout(const struct pf_ruleset *rs, const struct pf_rule *r,
    struct pfioc_rule *pr)
{
	pr->anchor_call[0] = 0;
	if (r->anchor == NULL)
		return (0);
	if (!r->anchor_relative) {
		strlcpy(pr->anchor_call, "/", sizeof(pr->anchor_call));
		strlcat(pr->anchor_call, r->anchor->path,
		    sizeof(pr->anchor_call));
	} else {
		char	*a, *p;
		int	 i;

		a = rs_malloc(MAXPATHLEN);
		if (a == NULL)
			return (1);
		if (rs == &pf_main_ruleset)
			a[0] = 0;
		else
			strlcpy(a, rs->anchor->path, MAXPATHLEN);
		for (i = 1; i < r->anchor_relative; ++i) {
			if ((p = strrchr(a, '/')) == NULL)
				p = a;
			*p = 0;
			strlcat(pr->anchor_call, "../",
			    sizeof(pr->anchor_call));
		}
		if (strncmp(a, r->anchor->path, strlen(a))) {
			DPFPRINTF(LOG_NOTICE,
			    "pf_anchor_copyout: '%s' '%s'", a,
			    r->anchor->path);
			rs_free(a, MAXPATHLEN);
			return (1);
		}
		if (strlen(r->anchor->path) > strlen(a))
			strlcat(pr->anchor_call, r->anchor->path + (a[0] ?
			    strlen(a) + 1 : 0), sizeof(pr->anchor_call));
		rs_free(a, MAXPATHLEN);
	}
	if (r->anchor_wildcard)
		strlcat(pr->anchor_call, pr->anchor_call[0] ? "/*" : "*",
		    sizeof(pr->anchor_call));
	return (0);
}

void
pf_remove_anchor(struct pf_rule *r)
{
	if (r->anchor == NULL)
		return;
	if (r->anchor->refcnt <= 0)
		DPFPRINTF(LOG_NOTICE, "pf_remove_anchor: broken refcount");
	else if (!--r->anchor->refcnt)
		pf_remove_if_empty_ruleset(&r->anchor->ruleset);
	r->anchor = NULL;
}