netdev - Re: [PATCH net 6/8] vrf: use RCU protection in l3mdev_l3

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250210012735.55713-1-kuniyu@amazon.com>
Date: Mon, 10 Feb 2025 10:27:35 +0900
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: <edumazet@...gle.com>
CC: <davem@...emloft.net>, <dsahern@...nel.org>, <eric.dumazet@...il.com>,
	<horms@...nel.org>, <kuba@...nel.org>, <kuniyu@...zon.com>,
	<netdev@...r.kernel.org>, <pabeni@...hat.com>
Subject: Re: [PATCH net 6/8] vrf: use RCU protection in l3mdev_l3_out()

From: Eric Dumazet <edumazet@...gle.com>
Date: Fri,  7 Feb 2025 13:58:38 +0000
> 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@...gle.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@...zon.com>

I wondered why syzbot didn't notice this and I confirmed that
list_first_or_null_rcu() doesn't have RCU annotation.