From: Guillaume Nault <gnault@redhat.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: netdev@vger.kernel.org, saeed@kernel.org, tparkin@katalix.com,
Cong Wang <cong.wang@bytedance.com>,
syzbot+52866e24647f9a23403f@syzkaller.appspotmail.com,
syzbot+94cc2a66fc228b23f360@syzkaller.appspotmail.com,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Jakub Sitnicki <jakub@cloudflare.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [Patch net v3 2/2] l2tp: close all race conditions in l2tp_tunnel_register()
Date: Mon, 16 Jan 2023 12:08:22 +0100 [thread overview]
Message-ID: <Y8UwJkRY1ISej+Zu@debian> (raw)
In-Reply-To: <20230114030137.672706-3-xiyou.wangcong@gmail.com>
On Fri, Jan 13, 2023 at 07:01:37PM -0800, Cong Wang wrote:
> From: Cong Wang <cong.wang@bytedance.com>
>
> The code in l2tp_tunnel_register() is racy in several ways:
>
> 1. It modifies the tunnel socket _after_ publishing it.
>
> 2. It calls setup_udp_tunnel_sock() on an existing socket without
> locking.
>
> 3. It changes sock lock class on fly, which triggers many syzbot
> reports.
>
> This patch amends all of them by moving socket initialization code
> before publishing and under sock lock. As suggested by Jakub, the
> l2tp lockdep class is not necessary as we can just switch to
> bh_lock_sock_nested().
Reviewed-by: Guillaume Nault <gnault@redhat.com>
next prev parent reply other threads:[~2023-01-16 11:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-14 3:01 [Patch net v3 0/2] l2tp: fix race conditions in l2tp_tunnel_register() Cong Wang
2023-01-14 3:01 ` [Patch net v3 1/2] l2tp: convert l2tp_tunnel_list to idr Cong Wang
2023-01-16 11:07 ` Guillaume Nault
2023-01-14 3:01 ` [Patch net v3 2/2] l2tp: close all race conditions in l2tp_tunnel_register() Cong Wang
2023-01-16 11:08 ` Guillaume Nault [this message]
2023-01-17 8:08 ` Eric Dumazet
2023-01-17 8:10 ` Eric Dumazet
2023-01-17 10:57 ` Guillaume Nault
2023-01-16 11:38 ` [Patch net v3 0/2] l2tp: fix " Tom Parkin
2023-01-16 13:50 ` patchwork-bot+netdevbpf
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