[precise 1/1] net: ipv4: current group_info should be put after using.

[Andy Whitcroft]

From: "Wang, Xiaoming" <xiaoming.wang at intel.com>

Plug a group_info refcount leak in ping_init.
group_info is only needed during initialization and
the code failed to release the reference on exit.
While here move grabbing the reference to a place
where it is actually needed.

Signed-off-by: Chuansheng Liu <chuansheng.liu at intel.com>
Signed-off-by: Zhang Dongxing <dongxing.zhang at intel.com>
Signed-off-by: xiaoming wang <xiaoming.wang at intel.com>
Signed-off-by: David S. Miller <davem at davemloft.net>

(backported from commit b04c46190219a4f845e46a459e3102137b7f6cac)
CVE-2014-2851
Conflicts:
	net/ipv4/ping.c
Signed-off-by: Andy Whitcroft <apw at canonical.com>
---
 net/ipv4/ping.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 00975b6..d495d4b 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -203,26 +203,33 @@ static int ping_init_sock(struct sock *sk)
 	struct net *net = sock_net(sk);
 	gid_t group = current_egid();
 	gid_t range[2];
-	struct group_info *group_info = get_current_groups();
-	int i, j, count = group_info->ngroups;
+	struct group_info *group_info;
+	int i, j, count;
+	int ret = 0;
 
 	inet_get_ping_group_range_net(net, range, range+1);
 	if (range[0] <= group && group <= range[1])
 		return 0;
 
+	group_info = get_current_groups();
+	count = group_info->ngroups;
 	for (i = 0; i < group_info->nblocks; i++) {
 		int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
 
 		for (j = 0; j < cp_count; j++) {
 			group = group_info->blocks[i][j];
 			if (range[0] <= group && group <= range[1])
-				return 0;
+				goto out_release_group;
 		}
 
 		count -= cp_count;
 	}
 
-	return -EACCES;
+	ret = -EACCES;
+
+out_release_group:
+	put_group_info(group_info);
+	return ret;
 }
 
 static void ping_close(struct sock *sk, long timeout)
-- 
1.9.1