diff options
| author | Weiming Shi <bestswngs@gmail.com> | 2026-09-21 10:08:22 +0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2026-09-30 09:35:20 +0200 |
| commit | 86b6471e690c67d4c5a1892993f34e080f1eae9d (patch) | |
| tree | 74e0f2ac8bbc93eb3e0e354adbe8ea9829718fa4 | |
| parent | f96e91748f6304668fe647e686d199d7207d36f1 (diff) | |
netfilter: nft_set_rbtree: skip transaction elements during GC
Since nft_set_commit_update() runs set commit callbacks before processing
NEWSETELEM transactions, nft_rbtree_gc_scan() can observe elements added by
the transaction being committed.
The scan records an interval end in rbe_end without checking the element's
transaction state. A later, unrelated expired start then moves both
elements to the expired list. The synchronous GC queue can free the new end
element before the transaction subsequently activates it, causing a
use-after-free.
Only consider elements that are fully active in both generations. This
keeps transaction-state elements out of the GC scan and preserves interval
pairing across skipped elements.
KASAN reports:
BUG: KASAN: slab-use-after-free in nft_setelem_activate
nft_setelem_activate net/netfilter/nf_tables_api.c:7047
nf_tables_commit net/netfilter/nf_tables_api.c:11137
Allocated by task 130:
nft_set_elem_init net/netfilter/nf_tables_api.c:6794
nft_add_set_elem net/netfilter/nf_tables_api.c:7523
Freed by task 130:
nft_trans_gc_trans_free net/netfilter/nf_tables_api.c:10506
rcu_core kernel/rcu/tree.c:2919
Fixes: 1e3b9e1c77fe ("netfilter: nf_tables: call set ops .commit when building new ruleset blob")
Reported-by: <co+ee5e50ef2670e5f4@bugs.sh>
Assisted-by: LLM
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/nft_set_rbtree.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index 9894832281c4..12431b55752f 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -900,6 +900,8 @@ static void nft_rbtree_gc_scan(struct nft_set *set) next = rb_next(node); rbe = rb_entry(node, struct nft_rbtree_elem, node); + if (!nft_set_elem_active(&rbe->ext, NFT_GENMASK_ANY)) + continue; /* elements are reversed in the rbtree for historical reasons, * from highest to lowest value, that is why end element is |