commit 1689f25924 upstream.
Overflow use refcount checks are not complete.
Add helper function to deal with object reference counter tracking.
Report -EMFILE in case UINT_MAX is reached.
nft_use_dec() splats in case that reference counter underflows,
which should not ever happen.
Add nft_use_inc_restore() and nft_use_dec_restore() which are used
to restore reference counter from error and abort paths.
Use u32 in nft_flowtable and nft_object since helper functions cannot
work on bitfields.
Remove the few early incomplete checks now that the helper functions
are in place and used to check for refcount overflow.
Fixes: 96518518cc ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
f3f0f95a02