netfilter: nf_tables: fix underflow in chain reference counter
Set element addition error path decrements reference counter on chains
twice: once on element release and again via nft_data_release().
Then,
d6b478666ffa ("netfilter: nf_tables: fix underflow in object
reference counter") incorrectly fixed this by removing the stateful
object reference count decrement.
Restore the stateful object decrement as in
b91d90368837 ("netfilter:
nf_tables: fix leaking object reference count") and let
nft_data_release() decrement the chain reference counter, so this is
done only once.
Fixes:
d6b478666ffa ("netfilter: nf_tables: fix underflow in object reference counter")
Fixes:
628bd3e49cba ("netfilter: nf_tables: drop map element references from preparation phase")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>