Imported Upstream version 1.2.1

1 files changed, 485 insertions, 0 deletions

diff --git a/src/filter.c b/src/filter.c
new file mode 100644
index 0000000..39dd4ca
--- /dev/null
+++ b/src/filter.c
@@ -0,0 +1,485 @@
+/*
+ * (C) 2006-2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * (C) 2011-2012 by Vyatta Inc <http://www.vyatta.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "filter.h"
+#include "bitops.h"
+#include "jhash.h"
+#include "hash.h"
+#include "vector.h"
+#include "conntrackd.h"
+#include "log.h"
+
+#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+
+struct ct_filter {
+	int logic[CT_FILTER_MAX];
+	u_int32_t l4protomap[IPPROTO_MAX/32];
+	u_int16_t statemap[IPPROTO_MAX];
+	struct hashtable *h;
+	struct hashtable *h6;
+	struct vector *v;
+	struct vector *v6;
+};
+
+/* XXX: These should be configurable, better use a rb-tree */
+#define FILTER_POOL_SIZE 128
+#define FILTER_POOL_LIMIT INT_MAX
+
+static uint32_t ct_filter_hash(const void *data, const struct hashtable *table)
+{
+	const uint32_t *f = data;
+
+	return jhash_1word(*f, 0) % table->hashsize;
+}
+
+static uint32_t ct_filter_hash6(const void *data, const struct hashtable *table)
+{
+	return jhash2(data, 4, 0) % table->hashsize;
+}
+
+static int ct_filter_compare(const void *data1, const void *data2)
+{
+	const struct ct_filter_ipv4_hnode *f1 = data1;
+	const uint32_t *f2 = data2;
+
+	return f1->ip == *f2;
+}
+
+static int ct_filter_compare6(const void *data1, const void *data2)
+{
+	const struct ct_filter_ipv6_hnode *f = data1;
+
+	return memcmp(f->ipv6, data2, sizeof(uint32_t)*4) == 0;
+}
+
+struct ct_filter *ct_filter_create(void)
+{
+	int i;
+	struct ct_filter *filter;
+
+	filter = calloc(sizeof(struct ct_filter), 1);
+	if (!filter)
+		return NULL;
+
+	filter->h = hashtable_create(FILTER_POOL_SIZE,
+				     FILTER_POOL_LIMIT,
+				     ct_filter_hash,
+				     ct_filter_compare);
+	if (!filter->h) {
+		free(filter);
+		return NULL;
+	}
+
+	filter->h6 = hashtable_create(FILTER_POOL_SIZE,
+				      FILTER_POOL_LIMIT,
+				      ct_filter_hash6,
+				      ct_filter_compare6);
+	if (!filter->h6) {
+		free(filter->h);
+		free(filter);
+		return NULL;
+	}
+
+	filter->v = vector_create(sizeof(struct ct_filter_netmask_ipv4));
+	if (!filter->v) {
+		free(filter->h6);
+		free(filter->h);
+		free(filter);
+		return NULL;
+	}
+
+	filter->v6 = vector_create(sizeof(struct ct_filter_netmask_ipv6));
+	if (!filter->v6) {
+		free(filter->v);
+		free(filter->h6);
+		free(filter->h);
+		free(filter);
+		return NULL;
+	}
+
+	for (i=0; i<CT_FILTER_MAX; i++)
+		filter->logic[i] = -1;
+
+	return filter;
+}
+
+void ct_filter_destroy(struct ct_filter *filter)
+{
+	hashtable_destroy(filter->h);
+	hashtable_destroy(filter->h6);
+	vector_destroy(filter->v);
+	vector_destroy(filter->v6);
+	free(filter);
+}
+
+/* this is ugly, but it simplifies read_config_yy.y */
+static struct ct_filter *__filter_alloc(struct ct_filter *filter)
+{
+	if (!STATE(us_filter)) {
+		STATE(us_filter) = ct_filter_create();
+		if (!STATE(us_filter)) {
+			fprintf(stderr, "Can't create ignore pool!\n");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	return STATE(us_filter);
+}
+
+void ct_filter_set_logic(struct ct_filter *filter,
+			 enum ct_filter_type type,
+			 enum ct_filter_logic logic)
+{
+	filter = __filter_alloc(filter);
+	filter->logic[type] = logic;
+}
+
+int ct_filter_add_ip(struct ct_filter *filter, void *data, uint8_t family)
+{
+	int id;
+	filter = __filter_alloc(filter);
+
+	switch(family) {
+		case AF_INET:
+			id = hashtable_hash(filter->h, data);
+			if (!hashtable_find(filter->h, data, id)) {
+				struct ct_filter_ipv4_hnode *n;
+				n = malloc(sizeof(struct ct_filter_ipv4_hnode));
+				if (n == NULL)
+					return 0;
+				memcpy(&n->ip, data, sizeof(uint32_t));
+				hashtable_add(filter->h, &n->node, id);
+				return 0;
+			}
+			break;
+		case AF_INET6:
+			id = hashtable_hash(filter->h6, data);
+			if (!hashtable_find(filter->h6, data, id)) {
+				struct ct_filter_ipv6_hnode *n;
+				n = malloc(sizeof(struct ct_filter_ipv6_hnode));
+				if (n == NULL)
+					return 0;
+				memcpy(n->ipv6, data, sizeof(uint32_t)*4);
+				hashtable_add(filter->h6, &n->node, id);
+				return 0;
+			}
+			break;
+	}
+	return 1;
+}
+
+static int cmp_ipv4_addr(const void *a, const void *b)
+{
+	return memcmp(a, b, sizeof(struct ct_filter_netmask_ipv4)) == 0;
+}
+
+static int cmp_ipv6_addr(const void *a, const void *b)
+{
+	return memcmp(a, b, sizeof(struct ct_filter_netmask_ipv6)) == 0;
+}
+
+int ct_filter_add_netmask(struct ct_filter *filter, void *data, uint8_t family)
+{
+	filter = __filter_alloc(filter);
+
+	switch(family) {
+		case AF_INET:
+			if (vector_iterate(filter->v, data, cmp_ipv4_addr)) {
+				errno = EEXIST;
+				return 0;
+			}
+			vector_add(filter->v, data);
+			break;
+		case AF_INET6:
+			if (vector_iterate(filter->v, data, cmp_ipv6_addr)) {
+				errno = EEXIST;
+				return 0;
+			}
+			vector_add(filter->v6, data);
+			break;
+	}
+	return 1;
+}
+
+void ct_filter_add_proto(struct ct_filter *f, int protonum)
+{
+	f = __filter_alloc(f);
+
+	set_bit_u32(protonum, f->l4protomap);
+}
+
+void ct_filter_add_state(struct ct_filter *f, int protonum, int val)
+{
+	f = __filter_alloc(f);
+
+	set_bit_u16(val, &f->statemap[protonum]);
+}
+
+static inline int
+__ct_filter_test_ipv4(struct ct_filter *f, const struct nf_conntrack *ct)
+{
+	int id_src, id_dst;
+	uint32_t src, dst;
+
+	/* we only use the real source and destination address */
+	src = nfct_get_attr_u32(ct, ATTR_ORIG_IPV4_SRC);
+	dst = nfct_get_attr_u32(ct, ATTR_REPL_IPV4_SRC);
+
+	id_src = hashtable_hash(f->h, &src);
+	id_dst = hashtable_hash(f->h, &dst);
+
+	return hashtable_find(f->h, &src, id_src) ||
+	       hashtable_find(f->h, &dst, id_dst);
+}
+
+static inline int
+__ct_filter_test_ipv6(struct ct_filter *f, const struct nf_conntrack *ct)
+{
+	int id_src, id_dst;
+	const uint32_t *src, *dst;
+
+	src = nfct_get_attr(ct, ATTR_ORIG_IPV6_SRC);
+	dst = nfct_get_attr(ct, ATTR_REPL_IPV6_SRC);
+
+	id_src = hashtable_hash(f->h6, src);
+	id_dst = hashtable_hash(f->h6, dst);
+
+	return hashtable_find(f->h6, src, id_src) ||
+	       hashtable_find(f->h6, dst, id_dst);
+}
+
+static int
+__ct_filter_test_mask4(const void *ptr, const void *ct)
+{
+	const struct ct_filter_netmask_ipv4 *elem = ptr;
+	const uint32_t src = nfct_get_attr_u32(ct, ATTR_ORIG_IPV4_SRC);
+	const uint32_t dst = nfct_get_attr_u32(ct, ATTR_REPL_IPV4_SRC);
+
+	return ((elem->ip & elem->mask) == (src & elem->mask) || 
+		(elem->ip & elem->mask) == (dst & elem->mask));
+}
+
+static int
+__ct_filter_test_mask6(const void *ptr, const void *ct)
+{
+	const struct ct_filter_netmask_ipv6 *elem = ptr;
+	const uint32_t *src = nfct_get_attr(ct, ATTR_ORIG_IPV6_SRC);
+	const uint32_t *dst = nfct_get_attr(ct, ATTR_REPL_IPV6_SRC);
+
+	return (((elem->ip[0] & elem->mask[0]) == (src[0] & elem->mask[0]) &&
+		 (elem->ip[1] & elem->mask[1]) == (src[1] & elem->mask[1]) &&
+		 (elem->ip[2] & elem->mask[2]) == (src[2] & elem->mask[2]) &&
+		 (elem->ip[3] & elem->mask[3]) == (src[3] & elem->mask[3])) ||
+		((elem->ip[0] & elem->mask[0]) == (dst[0] & elem->mask[0]) &&
+		 (elem->ip[1] & elem->mask[1]) == (dst[1] & elem->mask[1]) &&
+		 (elem->ip[2] & elem->mask[2]) == (dst[2] & elem->mask[2]) &&
+		 (elem->ip[3] & elem->mask[3]) == (dst[3] & elem->mask[3])));
+}
+
+static int
+__ct_filter_test_state(struct ct_filter *f, const struct nf_conntrack *ct)
+{
+	uint16_t val = 0;
+	uint8_t protonum = nfct_get_attr_u8(ct, ATTR_L4PROTO);
+
+	switch(protonum) {
+	case IPPROTO_TCP:
+		if (!nfct_attr_is_set(ct, ATTR_TCP_STATE))
+			return -1;
+
+		val = nfct_get_attr_u8(ct, ATTR_TCP_STATE);
+		break;
+	default:
+		return -1;
+	}
+
+	return test_bit_u16(val, &f->statemap[protonum]);
+}
+
+static int
+ct_filter_check(struct ct_filter *f, const struct nf_conntrack *ct)
+{
+	int ret, protonum = nfct_get_attr_u8(ct, ATTR_L4PROTO);
+
+	/* no event filtering at all */
+	if (f == NULL)
+		return 1;
+
+	if (f->logic[CT_FILTER_L4PROTO] != -1) {
+		ret = test_bit_u32(protonum, f->l4protomap);
+		if (ret ^ f->logic[CT_FILTER_L4PROTO])
+			return 0;
+	}
+
+	if (f->logic[CT_FILTER_ADDRESS] != -1) {
+		switch(nfct_get_attr_u8(ct, ATTR_L3PROTO)) {
+		case AF_INET:
+			ret = vector_iterate(f->v, ct, __ct_filter_test_mask4);
+			if (ret ^ f->logic[CT_FILTER_ADDRESS])
+				return 0;
+			ret = __ct_filter_test_ipv4(f, ct);
+			if (ret ^ f->logic[CT_FILTER_ADDRESS])
+				return 0;
+			break;
+		case AF_INET6:
+			ret = vector_iterate(f->v6, ct, __ct_filter_test_mask6);
+			if (ret ^ f->logic[CT_FILTER_ADDRESS])
+				return 0;
+			ret = __ct_filter_test_ipv6(f, ct);
+			if (ret ^ f->logic[CT_FILTER_ADDRESS])
+				return 0;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (f->logic[CT_FILTER_STATE] != -1) {
+		ret = __ct_filter_test_state(f, ct);
+		/* ret is -1 if we don't know what to do */
+		if (ret != -1 && ret ^ f->logic[CT_FILTER_STATE])
+			return 0;
+	}
+
+	return 1;
+}
+
+static inline int ct_filter_sanity_check(const struct nf_conntrack *ct)
+{
+	if (!nfct_attr_is_set(ct, ATTR_L3PROTO)) {
+		dlog(LOG_ERR, "missing layer 3 protocol");
+		return 0;
+	}
+
+	switch(nfct_get_attr_u8(ct, ATTR_L3PROTO)) {
+	case AF_INET:
+		if (!nfct_attr_is_set(ct, ATTR_IPV4_SRC) ||
+		    !nfct_attr_is_set(ct, ATTR_IPV4_DST)) {
+		    	dlog(LOG_ERR, "missing IPv4 address. "
+				      "You forgot to load "
+				      "nf_conntrack_ipv4?");
+			return 0;
+		}
+		break;
+	case AF_INET6:
+		if (!nfct_attr_is_set(ct, ATTR_IPV6_SRC) ||
+		    !nfct_attr_is_set(ct, ATTR_IPV6_DST)) {
+		    	dlog(LOG_ERR, "missing IPv6 address. "
+				      "You forgot to load "
+				      "nf_conntrack_ipv6?");
+			return 0;
+		}
+		break;
+	}
+	return 1;
+}
+
+/* we do user-space filtering for dump and resyncs */
+int ct_filter_conntrack(const struct nf_conntrack *ct, int userspace)
+{
+	/* missing mandatory attributes in object */
+	if (!ct_filter_sanity_check(ct))
+		return 1;
+
+	if (userspace && !ct_filter_check(STATE(us_filter), ct))
+		return 1;
+
+	return 0;
+}
+
+struct exp_filter {
+	struct list_head 	list;
+};
+
+struct exp_filter *exp_filter_create(void)
+{
+	struct exp_filter *f;
+
+	f = calloc(1, sizeof(struct exp_filter));
+	if (f == NULL)
+		return NULL;
+
+	INIT_LIST_HEAD(&f->list);
+	return f;
+}
+
+struct exp_filter_item {
+	struct list_head	head;
+	char			helper_name[NFCT_HELPER_NAME_MAX];
+};
+
+/* this is ugly, but it simplifies read_config_yy.y */
+static struct exp_filter *exp_filter_alloc(void)
+{
+	if (STATE(exp_filter) == NULL) {
+		STATE(exp_filter) = exp_filter_create();
+		if (STATE(exp_filter) == NULL) {
+			fprintf(stderr, "Can't init expectation filtering!\n");
+			return NULL;
+		}
+	}
+	return STATE(exp_filter);;
+}
+
+int exp_filter_add(struct exp_filter *f, const char *helper_name)
+{
+	struct exp_filter_item *item;
+
+	f = exp_filter_alloc();
+	if (f == NULL)
+		return -1;
+
+	list_for_each_entry(item, &f->list, head) {
+		if (strncasecmp(item->helper_name, helper_name,
+				NFCT_HELPER_NAME_MAX) == 0) {
+			return -1;
+		}
+	}
+	item = calloc(1, sizeof(struct exp_filter_item));
+	if (item == NULL)
+		return -1;
+
+	strncpy(item->helper_name, helper_name, NFCT_HELPER_NAME_MAX);
+	list_add(&item->head, &f->list);
+	return 0;
+}
+
+int exp_filter_find(struct exp_filter *f, const struct nf_expect *exp)
+{
+	struct exp_filter_item *item;
+
+	/* if filtering is not active, accept everything. */
+	if (f == NULL)
+		return 1;
+
+	list_for_each_entry(item, &f->list, head) {
+		const char *name = nfexp_get_attr(exp, ATTR_EXP_HELPER_NAME);
+
+		/* we allow partial matching to support things like sip-PORT. */
+		if (strncasecmp(item->helper_name, name,
+				strlen(item->helper_name)) == 0) {
+			return 1;
+		}
+	}
+	return 0;
+}