Paul Moore tracked a regression caused by a recent commit, which
mistakenly assumed that sk_filter() could be avoided if socket
had no current BPF filter.

The intent was to avoid udp_lib_checksum_complete() overhead.

But sk_filter() also checks skb_pfmemalloc() and
security_sock_rcv_skb(), so better call it.

Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NPaul Moore <paul@paul-moore.com>
Tested-by: NPaul Moore <paul@paul-moore.com>
Tested-by: NStephen Smalley <sds@tycho.nsa.gov>
Cc: samanthakumar <samanthakumar@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>