diff options
| author | Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr> | 2026-08-08 12:40:02 +0000 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2026-08-10 20:27:50 +0200 |
| commit | 2014ac62df9d45bb9a004a043e85df7be09ed780 (patch) | |
| tree | e369bd0bde999450942f7ed3d40123ab57c0c297 | |
| parent | d02f592064347e0c1e0d84f24941ad338838cc48 (diff) | |
netfilter: flowtable: publish GC-visible tuple last
nf_flow_table_iterate() only treats original-direction tuple nodes as
owning entries. Publishing the original node first lets GC observe and
free a flow while flow_offload_add() is still inserting the reply node.
Publish the reply node first and the original node last so GC never
sees a partially installed flow.
KASAN can trigger slab-use-after-free read and write reports in the
flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,
flow_offload_lookup, etc.).
Fixes: ac2a66665e23 ("netfilter: add generic flow table infrastructure")
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Assisted-by: Codex:gpt-5
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/nf_flow_table_core.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index b66e65439341..8b1165f2b5a4 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -332,17 +332,18 @@ int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow) flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow); err = rhashtable_insert_fast(&flow_table->rhashtable, - &flow->tuplehash[0].node, + &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node, nf_flow_offload_rhash_params); if (err < 0) return err; + /* GC only iterates original-direction entries; publish original last. */ err = rhashtable_insert_fast(&flow_table->rhashtable, - &flow->tuplehash[1].node, + &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node, nf_flow_offload_rhash_params); if (err < 0) { rhashtable_remove_fast(&flow_table->rhashtable, - &flow->tuplehash[0].node, + &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node, nf_flow_offload_rhash_params); return err; } |