netdev - Re: [PATCH] ptp: free ptp device pin descriptors properly

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Date:   Tue, 14 Jan 2020 10:59:57 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     vdronov@...hat.com
Cc:     antti.laakso@...el.com, netdev@...r.kernel.org,
        richardcochran@...il.com, sjohnsto@...hat.com, vlovejoy@...hat.com,
        linux-kernel@...r.kernel.org, artem.bityutskiy@...el.com
Subject: Re: [PATCH] ptp: free ptp device pin descriptors properly

From: Vladis Dronov <vdronov@...hat.com>
Date: Mon, 13 Jan 2020 14:00:09 +0100

> There is a bug in ptp_clock_unregister(), where ptp_cleanup_pin_groups()
> first frees ptp->pin_{,dev_}attr, but then posix_clock_unregister() needs
> them to destroy a related sysfs device.
> 
> These functions can not be just swapped, as posix_clock_unregister() frees
> ptp which is needed in the ptp_cleanup_pin_groups(). Fix this by calling
> ptp_cleanup_pin_groups() in ptp_clock_release(), right before ptp is freed.
> 
> This makes this patch fix an UAF bug in a patch which fixes an UAF bug.
> 
> Reported-by: Antti Laakso <antti.laakso@...el.com>
> Fixes: a33121e5487b ("ptp: fix the race between the release of ptp_clock and cdev")
> Link: https://lore.kernel.org/netdev/3d2bd09735dbdaf003585ca376b7c1e5b69a19bd.camel@intel.com/
> Signed-off-by: Vladis Dronov <vdronov@...hat.com>

Applied, thank you.