Re: selftests/capabilities: test FAIL on linux mainline and linux-next and PASS on linux-4.4.70+

From: Kees Cook
Date: Wed Jun 28 2017 - 00:36:34 EST


On Tue, Jun 27, 2017 at 4:16 PM, Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> wrote:
> On 06/27/2017 09:16 AM, Greg KH wrote:
>> On Tue, Jun 27, 2017 at 05:13:59PM +0200, Greg KH wrote:
>>> On Tue, Jun 27, 2017 at 02:10:32PM +0530, Naresh Kamboju wrote:
>>>> selftest capabilities test failed on linux mainline and linux-next and
>>>> PASS on linux-4.4.70+
>>>
>>> Odd. Any chance you can use 'git bisect' to track down the offending
>>> commit?
>>>
>>> Does this also fail on x86 or any other platform you have available?
>>> Let me go try this on my laptop...
>>
>> Ok, Linus's current tree (4.12.0-rc7+) also fails on this. I'm guessing
>> it's failing, it's hard to understand the output. If only we had TAP
>> output for this test :)
>
> As far as the output, it isn't bad. Not TAP13 will help make it better.
> The problem seems to with the individual messages error/info. messages
> themselves. This test has the quality of a developer unit test and the
> messages could be improved for non-developer use.
>
> I ran the test on 4.11.8-rc1+ and 4.9.35-rc1 see the same failure.
> It would be difficult to bisect this since it spans multiple releases.
> I am hoping Andy can give us some insight.

I bisected this to:

commit 380cf5ba6b0a0b307f4afb62b186ca801defb203
Author: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Date: Thu Jun 23 16:41:05 2016 -0500

fs: Treat foreign mounts as nosuid

I assume the test needs updating, but I bet Andy knows for sure. I can
look into this more closely in the morning.

-Kees

--
Kees Cook
Pixel Security