From: Jakub Kicinski <kuba@kernel.org>
To: Yang Yingliang <yangyingliang@huawei.com>
Cc: Leon Romanovsky <leon@kernel.org>, <netdev@vger.kernel.org>,
<jiri@nvidia.com>, <davem@davemloft.net>, <edumazet@google.com>,
<pabeni@redhat.com>
Subject: Re: [PATCH net] net: devlink: fix UAF in devlink_compat_running_version()
Date: Wed, 23 Nov 2022 18:47:38 -0800 [thread overview]
Message-ID: <20221123184738.29718806@kernel.org> (raw)
In-Reply-To: <405f703b-b97e-afdd-8d5f-48b8f99d045d@huawei.com>
On Wed, 23 Nov 2022 14:40:24 +0800 Yang Yingliang wrote:
> > +err_dl_unregister:
> > + devl_unregister(devlink);
> It races with dev_ethtool():
> dev_ethtool
> devlink_try_get()
> nsim_drv_probe
> devl_lock()
> devl_lock()
> devlink_unregister()
> devlink_put()
> wait_for_completion() <- the refcount
> is got in dev_ethtool, it causes ABBA deadlock
Yeah.. so my original design for the locking had a "devlink_is_alive()"
check for this exact reason:
https://lore.kernel.org/netdev/20211030231254.2477599-3-kuba@kernel.org/
and the devlink structure was properly refcounted (devlink_put() calls
devlink_free() when the last reference is released).
Pure references then need to check if the instance is still alive
after locking it. Which is fine, it should only happen in core code.
I think we should go back to that idea.
The waiting for references is a nightmare in the netdev code.
next prev parent reply other threads:[~2022-11-24 2:47 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 12:10 [PATCH net] net: devlink: fix UAF in devlink_compat_running_version() Yang Yingliang
2022-11-22 14:32 ` Leon Romanovsky
2022-11-22 15:25 ` Yang Yingliang
2022-11-22 19:04 ` Leon Romanovsky
2022-11-22 20:27 ` Jakub Kicinski
2022-11-23 1:50 ` Yang Yingliang
2022-11-23 6:40 ` Yang Yingliang
2022-11-23 7:41 ` Leon Romanovsky
2022-11-23 8:34 ` Yang Yingliang
2022-11-23 9:33 ` Leon Romanovsky
2022-11-23 19:18 ` Ido Schimmel
2022-11-24 2:18 ` Jakub Kicinski
2022-11-24 5:56 ` Leon Romanovsky
2022-11-28 9:20 ` Ido Schimmel
2022-11-28 9:58 ` Jiri Pirko
2022-11-28 11:50 ` Leon Romanovsky
2022-11-28 13:52 ` Jiri Pirko
2022-11-29 8:44 ` Leon Romanovsky
2022-11-29 9:05 ` Jiri Pirko
2022-11-29 11:20 ` Leon Romanovsky
2022-11-29 11:44 ` Jiri Pirko
2022-11-28 18:20 ` Jakub Kicinski
2022-11-29 8:31 ` Jiri Pirko
2022-11-30 2:18 ` Jakub Kicinski
2022-11-30 8:54 ` Leon Romanovsky
2022-11-30 11:32 ` Jiri Pirko
2022-11-30 16:36 ` Jakub Kicinski
2022-11-30 11:42 ` Jiri Pirko
2022-11-30 16:46 ` Jakub Kicinski
2022-11-30 17:00 ` Jiri Pirko
2022-11-30 17:20 ` Jakub Kicinski
2022-11-30 19:20 ` Leon Romanovsky
2022-12-01 8:40 ` Jiri Pirko
2022-12-01 10:05 ` Leon Romanovsky
2022-12-01 12:20 ` Jiri Pirko
2022-12-01 8:39 ` Jiri Pirko
2022-11-30 22:25 ` Jacob Keller
2022-11-24 2:20 ` Jakub Kicinski
2022-11-24 2:47 ` Jakub Kicinski [this message]
2022-11-24 7:28 ` Yang Yingliang
2022-11-28 10:01 ` Jiri Pirko
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