From: Aohan Mei nft_setelem_catchall_insert() looks up duplicates with nft_set_elem_active() only, while nft_set_catchall_lookup() and the dump path additionally skip expired elements. Once a catchall element with a timeout expires, this predicate drift makes it invisible to userspace dumps, yet it still blocks re-insertion: with NLM_F_EXCL the request fails with -EEXIST, and without it the request reports success but silently inserts nothing. The stale entry only goes away when the (user-tunable) gc interval elapses, so the catchall rule may silently stop matching for an arbitrarily long time after its first expiration. The delete path shows the same drift: nft_setelem_catchall_deactivate() picks the first active-next entry in the catchall list, so with an expired entry still pending GC it retires the stale entry instead of the fresh one, and it deactivates an element that userspace no longer sees instead of failing with -ENOENT. Align both walks with the lookup and dump predicates: only an element that is active and not expired counts as a duplicate or delete candidate, using the per-netns timestamp taken at transaction start, in line with the set backend .insert/.deactivate and catchall GC sync paths. Reported-by: TencentOS Corvus AI Cc: stable@vger.kernel.org Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support") Assisted-by: CodeBuddy:Kimi-K3 Signed-off-by: Aohan Mei --- v3: use the per-netns transaction timestamp via nft_net_tstamp() instead of sampling current time, per Pablo's review: control plane insert and deactivate paths must not let an element expire mid-transaction. v2: drop the is_dead check, it does not belong to this dedup walk; also skip expired catchall elements in the delete path. v1: https://lore.kernel.org/netfilter-devel/REPLACE-WITH-V1-MESSAGE-ID net/netfilter/nf_tables_api.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 765a92fa90d62..7ef2e19e6655a 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -6991,11 +6991,13 @@ static int nft_setelem_catchall_insert(const struct net *net, { struct nft_set_elem_catchall *catchall; u8 genmask = nft_genmask_next(net); + u64 tstamp = nft_net_tstamp(net); struct nft_set_ext *ext; list_for_each_entry(catchall, &set->catchall_list, list) { ext = nft_set_elem_ext(set, catchall->elem); - if (nft_set_elem_active(ext, genmask)) { + if (nft_set_elem_active(ext, genmask) && + !__nft_set_elem_expired(ext, tstamp)) { *priv = catchall->elem; return -EEXIST; } @@ -7088,11 +7090,13 @@ static int nft_setelem_catchall_deactivate(const struct net *net, struct nft_set_elem *elem) { struct nft_set_elem_catchall *catchall; + u64 tstamp = nft_net_tstamp(net); struct nft_set_ext *ext; list_for_each_entry(catchall, &set->catchall_list, list) { ext = nft_set_elem_ext(set, catchall->elem); - if (!nft_is_active_next(net, ext)) + if (!nft_is_active_next(net, ext) || + __nft_set_elem_expired(ext, tstamp)) continue; kfree(elem->priv); -- 2.43.7