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 the expired object 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 transparently 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>
---
net/netfilter/nf_tables_api.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index f0d2bf68731c..c7b3df6a915c 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -10651,11 +10651,6 @@ 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;
}
@@ -10672,6 +10667,14 @@ 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;
--
2.30.2
