5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 6d0ce46a93135d96b7fa075a94a88fe0da8e8773 ]
l3mdev_l3_out() can be called without RCU being held:
raw_sendmsg() ip_push_pending_frames() ip_send_skb() ip_local_out() __ip_local_out() l3mdev_ip_out()
Add rcu_read_lock() / rcu_read_unlock() pair to avoid a potential UAF.
Fixes: a8e3e1a9f020 ("net: l3mdev: Add hook to output path") Signed-off-by: Eric Dumazet edumazet@google.com Reviewed-by: David Ahern dsahern@kernel.org Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20250207135841.1948589-7-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/l3mdev.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/include/net/l3mdev.h b/include/net/l3mdev.h index e942372b077b5..062da1588be05 100644 --- a/include/net/l3mdev.h +++ b/include/net/l3mdev.h @@ -179,10 +179,12 @@ struct sk_buff *l3mdev_l3_out(struct sock *sk, struct sk_buff *skb, u16 proto) if (netif_is_l3_slave(dev)) { struct net_device *master;
+ rcu_read_lock(); master = netdev_master_upper_dev_get_rcu(dev); if (master && master->l3mdev_ops->l3mdev_l3_out) skb = master->l3mdev_ops->l3mdev_l3_out(master, sk, skb, proto); + rcu_read_unlock(); }
return skb;