netfilter: flowtable: publish GC-visible tuple last

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[ Upstream commit 2014ac62df ]

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: ac2a66665e ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Jérémy Jean 2026-08-08 12:40:02 +00:00 • committed by Greg Kroah-Hartman

parent 6ee3803c22

commit be345dcbdd

1 changed files with 4 additions and 3 deletions

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net/netfilter/nf_flow_table_core.c

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