This is a note to let you know that I've just added the patch titled
netfilter: nf_tables: release mutex after nft_gc_seq_end from abort path
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nf_tables-release-mutex-after-nft_gc_seq_e.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a68a782128c196d0cdbb6aab69bfdf85b49da39a
Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date: Mon Apr 8 23:21:41 2024 +0200
netfilter: nf_tables: release mutex after nft_gc_seq_end from abort path
commit 0d459e2ffb541841714839e8228b845458ed3b27 upstream.
The commit mutex should not be released during the critical section
between nft_gc_seq_begin() and nft_gc_seq_end(), otherwise, async GC
worker could collect expired objects and get the released commit lock
within the same GC sequence.
nf_tables_module_autoload() temporarily releases the mutex to load
module dependencies, then it goes back to replay the transaction again.
Move it at the end of the abort phase after nft_gc_seq_end() is called.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 720344340fb9 ("netfilter: nf_tables: GC transaction race with abort path")
Reported-by: Kuan-Ting Chen <hexrabbit@xxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index b719f3517caf1..8dd7efb3b8f7b 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -7696,11 +7696,6 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
nf_tables_abort_release(trans);
}
- if (action == NFNL_ABORT_AUTOLOAD)
- nf_tables_module_autoload(net);
- else
- nf_tables_module_autoload_cleanup(net);
-
return err;
}
@@ -7717,6 +7712,14 @@ static int nf_tables_abort(struct net *net, struct sk_buff *skb,
WARN_ON_ONCE(!list_empty(&nft_net->commit_list));
+ /* module autoload needs to happen after GC sequence update because it
+ * temporarily releases and grabs mutex again.
+ */
+ if (action == NFNL_ABORT_AUTOLOAD)
+ nf_tables_module_autoload(net);
+ else
+ nf_tables_module_autoload_cleanup(net);
+
mutex_unlock(&nft_net->commit_mutex);
return ret;
