netfilter: ipset: hash:net,iface fixed to handle overlapping nets behind different interfaces

If overlapping networks with different interfaces was added to
the set, the type did not handle it properly. Example

    ipset create test hash:net,iface
    ipset add test 192.168.0.0/16,eth0
    ipset add test 192.168.0.0/24,eth1

Now, if a packet was sent from 192.168.0.0/24,eth0, the type returned
a match.

In the patch the algorithm is fixed in order to correctly handle
overlapping networks.

Limitation: the same network cannot be stored with more than 64 different
interfaces in a single set.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 32 insertions, 8 deletions

diff --git a/net/netfilter/ipset/ip_set_hash_netiface.c b/net/netfilter/ipset/ip_set_hash_netiface.c
index 3d6c53b6211a..e13095deb50d 100644
--- a/net/netfilter/ipset/ip_set_hash_netiface.c
+++ b/net/netfilter/ipset/ip_set_hash_netiface.c
@@ -99,7 +99,7 @@ iface_test(struct rb_root *root, const char **iface)
 
 	while (n) {
 		const char *d = iface_data(n);
-		int res = ifname_compare(*iface, d);
+		long res = ifname_compare(*iface, d);
 
 		if (res < 0)
 			n = n->rb_left;
@@ -121,7 +121,7 @@ iface_add(struct rb_root *root, const char **iface)
 
 	while (*n) {
 		char *ifname = iface_data(*n);
-		int res = ifname_compare(*iface, ifname);
+		long res = ifname_compare(*iface, ifname);
 
 		p = *n;
 		if (res < 0)
@@ -159,31 +159,42 @@ hash_netiface_same_set(const struct ip_set *a, const struct ip_set *b);
 
 /* The type variant functions: IPv4 */
 
+struct hash_netiface4_elem_hashed {
+	__be32 ip;
+	u8 physdev;
+	u8 cidr;
+	u16 padding;
+};
+
+#define HKEY_DATALEN	sizeof(struct hash_netiface4_elem_hashed)
+
 /* Member elements without timeout */
 struct hash_netiface4_elem {
 	__be32 ip;
-	const char *iface;
 	u8 physdev;
 	u8 cidr;
 	u16 padding;
+	const char *iface;
 };
 
 /* Member elements with timeout support */
 struct hash_netiface4_telem {
 	__be32 ip;
-	const char *iface;
 	u8 physdev;
 	u8 cidr;
 	u16 padding;
+	const char *iface;
 	unsigned long timeout;
 };
 
 static inline bool
 hash_netiface4_data_equal(const struct hash_netiface4_elem *ip1,
-			  const struct hash_netiface4_elem *ip2)
+			  const struct hash_netiface4_elem *ip2,
+			  u32 *multi)
 {
 	return ip1->ip == ip2->ip &&
 	       ip1->cidr == ip2->cidr &&
+	       (++*multi) &&
 	       ip1->physdev == ip2->physdev &&
 	       ip1->iface == ip2->iface;
 }
@@ -257,6 +268,7 @@ nla_put_failure:
 
 #define IP_SET_HASH_WITH_NETS
 #define IP_SET_HASH_WITH_RBTREE
+#define IP_SET_HASH_WITH_MULTI
 
 #define PF		4
 #define HOST_MASK	32
@@ -424,29 +436,40 @@ hash_netiface_same_set(const struct ip_set *a, const struct ip_set *b)
 
 /* The type variant functions: IPv6 */
 
+struct hash_netiface6_elem_hashed {
+	union nf_inet_addr ip;
+	u8 physdev;
+	u8 cidr;
+	u16 padding;
+};
+
+#define HKEY_DATALEN	sizeof(struct hash_netiface6_elem_hashed)
+
 struct hash_netiface6_elem {
 	union nf_inet_addr ip;
-	const char *iface;
 	u8 physdev;
 	u8 cidr;
 	u16 padding;
+	const char *iface;
 };
 
 struct hash_netiface6_telem {
 	union nf_inet_addr ip;
-	const char *iface;
 	u8 physdev;
 	u8 cidr;
 	u16 padding;
+	const char *iface;
 	unsigned long timeout;
 };
 
 static inline bool
 hash_netiface6_data_equal(const struct hash_netiface6_elem *ip1,
-			  const struct hash_netiface6_elem *ip2)
+			  const struct hash_netiface6_elem *ip2,
+			  u32 *multi)
 {
 	return ipv6_addr_cmp(&ip1->ip.in6, &ip2->ip.in6) == 0 &&
 	       ip1->cidr == ip2->cidr &&
+	       (++*multi) &&
 	       ip1->physdev == ip2->physdev &&
 	       ip1->iface == ip2->iface;
 }
@@ -681,6 +704,7 @@ hash_netiface_create(struct ip_set *set, struct nlattr *tb[], u32 flags)
 	h->maxelem = maxelem;
 	get_random_bytes(&h->initval, sizeof(h->initval));
 	h->timeout = IPSET_NO_TIMEOUT;
+	h->ahash_max = AHASH_MAX_SIZE;
 
 	hbits = htable_bits(hashsize);
 	h->table = ip_set_alloc(