Re: /proc/pid/fd/ shows strange mode when executed via sudo.

[ebiederm@xmission.com (Eric W. Biederman)]

Linus Torvalds <torvalds@linux-foundation.org> writes:

> On Fri, May 18, 2012 at 9:08 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> I would suggest just moving the i_mode initialization from
>> proc_fd_instantiate() into the revalidate function that we already
>> have, and that already fixes up i_uid/i_gid etc. Attached is a TOTALLY
>> UNTESTED patch that does this, and actually seems to simplify things
>> in the process.
>
> Ok, so it's now "tested" in the sense that it works for me, and fixes
> both my and your test-cases.
>
> Which doesn't mean that it is bug-free of course, but it does seem to
> be a sane patch that actually cleans things up.
>
> I'll delay committing it in case somebody hollers, but I think I'll
> mark it for stable too since this issue seems age-old, and the fix
> looks good.
>
> Ack/nak? Can anybody find anything wrong in that patch?

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>

It looks reasonable.

I am a tad leery of the d_add without setting inode->i_mode
but the dcache lookup will have to call revalidate before
we access the inode so I don't expect a problem there.

Eric