2022-11-03 01:25:38

by Ziyang Xuan (William)

Subject: [PATCH] netfilter: nfnetlink: fix potential dead lock in nfnetlink_rcv_msg()

When type is NFNL_CB_MUTEX and -EAGAIN error occur in nfnetlink_rcv_msg(),
it does not execute nfnl_unlock(). That would trigger potential dead lock.

Fixes: 50f2db9e368f ("netfilter: nfnetlink: consolidate callback types")
Signed-off-by: Ziyang Xuan <[email protected]>
---
net/netfilter/nfnetlink.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 9c44518cb70f..6d18fb346868 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -294,6 +294,7 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
nfnl_lock(subsys_id);
if (nfnl_dereference_protected(subsys_id) != ss ||
nfnetlink_find_client(type, ss) != nc) {
+ nfnl_unlock(subsys_id);
err = -EAGAIN;
break;
}
--
2.25.1

2022-11-03 11:39:17

by Florian Westphal

Subject: Re: [PATCH] netfilter: nfnetlink: fix potential dead lock in nfnetlink_rcv_msg()

Ziyang Xuan <[email protected]> wrote:
> When type is NFNL_CB_MUTEX and -EAGAIN error occur in nfnetlink_rcv_msg(),
> it does not execute nfnl_unlock(). That would trigger potential dead lock.
>
> Fixes: 50f2db9e368f ("netfilter: nfnetlink: consolidate callback types")

Applied to nf:testing, thanks.