From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from a.ns.miles-group.at ([95.130.255.143] helo=radon.swed.at)
 by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux))
 id 1ZRy9b-0006aH-LO
 for linux-mtd@lists.infradead.org; Wed, 19 Aug 2015 07:51:24 +0000
Subject: Re: [kernel.org bug 103071] Dead "security.*" xattr code in ubifs
To: Sheng Yong <shengyong1@huawei.com>,
 =?UTF-8?Q?Andreas_Gr=c3=bcnbacher?= <andreas.gruenbacher@gmail.com>
References: <CAHpGcM+bkFA-UDM0FKwH=FkS9+TWv_Br7nWJXSpKDquo5n_gFw@mail.gmail.com>
 <CAFLxGvxPGZoRX3Ft_g59fzfLhoOmEES=q-oPBmYuGVBzn-dRUA@mail.gmail.com>
 <55D3D6BB.3030307@huawei.com> <55D3DDD1.8060405@huawei.com>
 <55D42959.5070605@nod.at> <55D431E8.5040509@huawei.com>
Cc: snijsure@grid-net.com, Artem Bityutskiy <dedekind1@gmail.com>,
 "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
 mkl@pengutronix.de, gratian.crisan@ni.com, brad.mouring@ni.com
From: Richard Weinberger <richard@nod.at>
Message-ID: <55D43564.3060009@nod.at>
Date: Wed, 19 Aug 2015 09:51:00 +0200
MIME-Version: 1.0
In-Reply-To: <55D431E8.5040509@huawei.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
List-Id: Linux MTD discussion mailing list <linux-mtd.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-mtd/>
List-Post: <mailto:linux-mtd@lists.infradead.org>
List-Help: <mailto:linux-mtd-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=subscribe>

Am 19.08.2015 um 09:36 schrieb Sheng Yong:
> 
> 
> On 8/19/2015 2:59 PM, Richard Weinberger wrote:
>> Am 19.08.2015 um 03:37 schrieb Sheng Yong:
>>>
>>>
>>> On 8/19/2015 9:07 AM, Sheng Yong wrote:
>>>> Hi,
>>>>
>>>> On 8/19/2015 4:55 AM, Richard Weinberger wrote:
>>>>> Andreas,
>>>>>
>>>>> On Tue, Aug 18, 2015 at 2:15 PM, Andreas Grünbacher
>>>>> <andreas.gruenbacher@gmail.com> wrote:
>>>>>> Hello,
>>>>>>
>>>>>> FYI, I've filed the following bug report against ubifs:
>>>>>>
>>>>>>> ubifs sets sb->s_xattr to ubifs_xattr_handlers which contains a handler for
>>>>>>> "security.*" xattrs. The s_xattr handlers are never used because ubifs uses
>>>>>>> its own ubifs_{get,set,list,remove}xattr inode operations instead of
>>>>>>> generic_{get,set,list,remove}xattr inode operations though.
>>>>>>
>>>>>> https://bugzilla.kernel.org/show_bug.cgi?id=103071
>>>>>
>>>>> Thanks for reporting.
>>> My bad for didn't reply at the right line :(
>>>> This is because UBIFS did not implement extended attribute in the geneirc way
>>>> (by calling generic_*xattr()). We could create an xattr_handler to have these
>>>> dead functions called (in fact, I did that), but doing this seems just another
>>>> encapsulation and makes no sense. So I think we could remove these dead code
>>>> directly.
>>
>> So, that would be a revert of commit d7f0b70d30ffb9bbe6b8a3e1035cf0b79965ef53?
> I think we still need security xattr, so security stuff should be initialized
> when creating inodes.
>> I don't get what d7f0b70d30ffb9bbe6b8a3e1035cf0b79965ef53 was supposed to do
>> as it seems to be a no-op. :-)
> AFAIK, geneirc_*attr() will go though sb->s_xattr to find the xattr_handler
> which matches the xattr prefix, and generic_*attr() should have been triggered
> from inode_operations. However, UBIFS uses ubifs_*attr in inode_operations
> instead of these generic interfaces. So `ubifs_xattr_security_handler' defined
> in fs/ubifs/xattr.c is useless, so are the security_*attr() functions. These
> functions will never being called, set/get/list security xattr is still done
> by calling ubifs_*attr() like other xattr.

My concern is not that we don't need these xattr.
I'm concerned about commit d7f0b70d30ffb9bbe6b8a3e1035cf0b79965ef53.
Today it seems to be a no-op. Did it ever work?

Clearly something went wrong. :(

Thanks,
//richard