Cherry-pick from commit 6acc5c2910689fc6ee181bf63085c5efff6a42bd Returns the owner uid of the socket inside a sk_buff. This is useful to perform per-UID accounting of network traffic or per-UID packet filtering. The socket need to be a fullsock otherwise overflowuid is returned. Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Bug: 30950746 Change-Id: Idc00947ccfdd4e9f2214ffc4178d701cd9ead0ac