From dbb8aa5b142b72cab6bc92bd8574d7104cb2a3e4 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 7 Feb 2025 13:58:38 +0000
Subject: [PATCH] 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: 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 031c661aa14df..bdfa9d414360c 100644
--- a/include/net/l3mdev.h
+++ b/include/net/l3mdev.h
@@ -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;
--
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