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

From: Vasily Averin
Date: Thu Jul 24 2014 - 02:00:10 EST


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@xxxxxxxxxx>
>
> Acked-by: Ian Kent <raven@xxxxxxxxxx>

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