Re: [PATCH 0/2] kernel/sys.c: for setfsgid(), return the current gid when error occurs

[Chen Gang <gang.chen@asianux.com>]

On 08/07/2013 02:36 AM, Kees Cook wrote:
> On Tue, Aug 6, 2013 at 1:00 AM, Chen Gang <gang.chen@asianux.com> wrote:
>> They are 2 related patches for setfsgid().
>>
>> Patch 1 for bug fix: return the current gid when error occurs.
>> Patch 2 for cleaning code: remove useless variable 'old_fsgid'.
>>
>> Signed-off-by: Chen Gang <gang.chen@asianux.com>
>> --
>>  kernel/sys.c |   15 +++++----------
>>  1 files changed, 5 insertions(+), 10 deletions(-)
> 
> Making a change like this might have dramatic effects. So, a few
> questions, to help better understand:
> 
> How long as the behavior been this way on Linux?
> What is the origin of the documentation that states it differently?
> Do existing userspace tools already depend on the current behavior?
> What specific problem will be solved by changing this?
> 

Firstly, your questions are necessary and valuable to get reply.

But sorry, I only find it by reading code, and not quite familiar with
the details (e.g. how to use it, and its history ...).

I only know the original implementation has a kernel API related issue
(at least now, it is), and try to send a possible fixing patch to
mailing list for getting more discussion and better fixing.

So, welcome any members to help reply your valuable questions (and I
should also try to answer them, but at least, I really needs time to
familiar about it).


> Thanks,
> 
> -Kees
> 

Thanks.
-- 
Chen Gang