[CRIU] [PATCH] security: check_ids - return true if [se]?[ug]id is the same as task id

[Pavel Emelyanov]

On 06/19/2014 02:54 PM, Ruslan Kuprieiev wrote:
> On 19.06.2014 13:50, Pavel Emelyanov wrote:
>> On 06/19/2014 05:06 AM, Ruslan Kuprieiev wrote:
>>> After a bit more thinking I don't like the idea of checking owner and
>>> perms at all.
>>> And I think we should create images with owner == current user.
>>> Let me explain why.
>>> Lets imagine, I'm a developer of, for example, a game, who wants to save by
>>> dumping and load by restoring( well, why not?=) ). I want to be able to
>>> delete some old saves, but currently i'm not able, because images are
>>> owned by root and
>>> perms == 0644.
>>> Playing the game as root isn't cool =).
>> Removing a file doesn't requite _it_ to be writable. It requires
>> directory the files are in to be such.
> 
> Oh, now I see.
> 
>>> Still, there is a bug, when one can't dump/restore process which
>>> r/e/sgid doesn't
>>> match user crgid. crgid is primary group of the user and if it doesn't
>>> match sgid
>>> it doesn't mean that user isn't in additional group sgid.
>>> So, it looks like we should divide uid and gid checking. For gid
>>> checking we should
>>> compare crgid with additional groups of the user.
> 
> So, how about additional groups checking?

Yes, I agree. Additional groups are to be checked as well. But anyway,
the rule of a thumb from my perspective is -- if a user, that asks to
restore from images that fully belong to root and can _not_ modify them
-- restore is allowed w/o any restrictions.

Thanks,
Pavel