From: Eric Dumazet <edumazet@google.com> stable inclusion from stable-v6.6.79 commit c40cb5c03e37552d6eff963187109e2c3f78ef6f category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPCA6 CVE: CVE-2025-21791 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- [ 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> Signed-off-by: Liu Jian <liujian56@huawei.com> --- include/net/l3mdev.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/net/l3mdev.h b/include/net/l3mdev.h index ba8dc2523c59..eb5ef1b2e059 100644 --- a/include/net/l3mdev.h +++ b/include/net/l3mdev.h @@ -204,10 +204,12 @@ 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; -- 2.34.1