linux-kernel - Re: [PATCH v4] fs: umount on symlink leaks mnt count

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Date:	Thu, 24 Jul 2014 09:59:40 +0400
From:	Vasily Averin <vvs@...allels.com>
To:	unlisted-recipients:; (no To-header on input)
CC:	Alexander Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Richard Weinberger <richard.weinberger@...il.com>
Subject: Re: [PATCH  v4] fs: umount on symlink leaks mnt count

CVE-2014-5045 was assigned for this issue

On 07/23/2014 10:06 AM, Ian Kent wrote:
> On Mon, 2014-07-21 at 12:30 +0400, Vasily Averin wrote:
>> Currently umount on symlink blocks following umount:
>>
>> /vz is separate mount
>>
>> # ls /vz/ -al | grep test
>> drwxr-xr-x.  2 root root       4096 Jul 19 01:14 testdir
>> lrwxrwxrwx.  1 root root         11 Jul 19 01:16 testlink -> /vz/testdir
>> # umount -l /vz/testlink
>> umount: /vz/testlink: not mounted (expected)
>>
>> # lsof /vz
>> # umount /vz
>> umount: /vz: device is busy. (unexpected)
>>
>> In this case mountpoint_last() gets an extra refcount on path->mnt
>>
>> Signed-off-by: Vasily Averin <vvs@...nvz.org>
> 
> Acked-by: Ian Kent <raven@...maw.net>

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