netfilter: nfnetlink_queue: fix secctx memory leak

netfilter: nfnetlink_queue: fix secctx memory leak

[ Upstream commit 77c1c03c5b8ef28e55bb0aff29b1e006037ca645 ]

We must call security_release_secctx to free the memory returned by
security_secid_to_secctx, otherwise memory may be leaked forever.

Fixes: ef493bd930ae ("netfilter: nfnetlink_queue: add security context information")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>