netfilter: xt_socket: fix compilation warnings with gcc 4.7

This patch fixes compilation warnings in xt_socket with gcc-4.7.

In file included from net/netfilter/xt_socket.c:22:0:
net/netfilter/xt_socket.c: In function ‘socket_mt6_v1’:
include/net/netfilter/nf_tproxy_core.h:175:23: warning: ‘sport’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:265:16: note: ‘sport’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:175:23: warning: ‘dport’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:265:9: note: ‘dport’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:175:6: warning: ‘saddr’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:264:27: note: ‘saddr’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:175:6: warning: ‘daddr’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:264:19: note: ‘daddr’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
net/netfilter/xt_socket.c: In function ‘socket_match.isra.4’:
include/net/netfilter/nf_tproxy_core.h:75:2: warning: ‘protocol’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:113:5: note: ‘protocol’ was declared here
In file included from include/net/tcp.h:37:0,
                 from net/netfilter/xt_socket.c:17:
include/net/inet_hashtables.h:356:45: warning: ‘sport’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:112:16: note: ‘sport’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:106:23: warning: ‘dport’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:112:9: note: ‘dport’ was declared here
In file included from include/net/tcp.h:37:0,
                 from net/netfilter/xt_socket.c:17:
include/net/inet_hashtables.h:356:15: warning: ‘saddr’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:111:16: note: ‘saddr’ was declared here
In file included from include/net/tcp.h:37:0,
                 from net/netfilter/xt_socket.c:17:
include/net/inet_hashtables.h:356:15: warning: ‘daddr’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:111:9: note: ‘daddr’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
net/netfilter/xt_socket.c: In function ‘socket_mt6_v1’:
include/net/netfilter/nf_tproxy_core.h:175:23: warning: ‘sport’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:268:16: note: ‘sport’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:175:23: warning: ‘dport’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:268:9: note: ‘dport’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:175:6: warning: ‘saddr’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:267:27: note: ‘saddr’ was declared here
In file included from net/netfilter/xt_socket.c:22:0:
include/net/netfilter/nf_tproxy_core.h:175:6: warning: ‘daddr’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/xt_socket.c:267:19: note: ‘daddr’ was declared here

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/xt_socket.c

@@ -108,9 +108,9 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par,
 	const struct iphdr *iph = ip_hdr(skb);
 	struct udphdr _hdr, *hp = NULL;
 	struct sock *sk;
-	__be32 daddr, saddr;
-	__be16 dport, sport;
-	u8 protocol;
+	__be32 uninitialized_var(daddr), uninitialized_var(saddr);
+	__be16 uninitialized_var(dport), uninitialized_var(sport);
+	u8 uninitialized_var(protocol);
 #ifdef XT_SOCKET_HAVE_CONNTRACK
 	struct nf_conn const *ct;
 	enum ip_conntrack_info ctinfo;
@@ -261,9 +261,9 @@ socket_mt6_v1(const struct sk_buff *skb, struct xt_action_param *par)
 	struct ipv6hdr *iph = ipv6_hdr(skb);
 	struct udphdr _hdr, *hp = NULL;
 	struct sock *sk;
-	struct in6_addr *daddr, *saddr;
-	__be16 dport, sport;
-	int thoff = 0, tproto;
+	struct in6_addr *daddr = NULL, *saddr = NULL;
+	__be16 uninitialized_var(dport), uninitialized_var(sport);
+	int thoff = 0, uninitialized_var(tproto);
 	const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;
 
 	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);