vrf: use RCU protection in l3mdev_l3_out()

[ 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: a8e3e1a9f0 ("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>
This commit is contained in:
Eric Dumazet 2025-02-07 13:58:38 +00:00 committed by Greg Kroah-Hartman
parent 35b3f615fb
commit c40cb5c03e
1 changed files with 2 additions and 0 deletions

View File

@ -198,10 +198,12 @@ 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;