Consider two ranges in a netfilter verdict map: * keys 10-19 accept packets, and * keys 30-39 jump to chain 'victim'. Now, delete the end marker at 20. The lookup array now uses element 30 as the first range's end, so an INTERVAL_END query for key 15 returns element 30, including its jump verdict and chain pointer. This can make KASAN reports a UAF after the GC releases reference chain for 30 that has expired: BUG: KASAN: slab-use-after-free in nft_verdict_dump+0xdd/0x110 Read of size 8 at addr ff110000009dfb58 by task repro/50 ... Call Trace: ... nft_verdict_dump+0xdd/0x110 nft_data_dump+0x4d/0x80 nf_tables_fill_setelem+0x30b/0x8a0 ? __asan_memcpy+0x3c/0x60 nf_tables_fill_setelem_info+0x1b0/0x200 nft_get_set_elem+0x3fd/0x4b0 ... Freed by task 24: ... kfree+0x1a5/0x280 nf_tables_trans_destroy_work+0x2cb/0x520 Reject expired endpoints in nft_rbtree_get() before returning them. Fixes: 2aa34191f06f ("netfilter: nft_set_rbtree: use binary search array in get command") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Jérémy Jean --- net/netfilter/nft_set_rbtree.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index 9894832..1fd9cbe 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -187,6 +187,8 @@ nft_rbtree_get(const struct net *net, const struct nft_set *set, if (flags & NFT_SET_ELEM_INTERVAL_END) { if (!interval->to) return NULL; + if (nft_set_elem_expired(interval->to)) + return ERR_PTR(-ENOENT); rbe = container_of(interval->to, struct nft_rbtree_elem, ext); } else { -- 2.47.3