Re: [kernel.org bug 103071] Dead "security.*" xattr code in ubifs

[Richard Weinberger <richard@nod.at>]

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