Re: [PATCH 3/3] CRED: Move the effective capabilities into the cred struct

From: Al Viro
Date: Wed Sep 26 2007 - 14:24:22 EST


On Wed, Sep 19, 2007 at 09:11:26PM -0700, Andrew Morgan wrote:
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> David Howells wrote:
> > Move the effective capabilities mask from the task struct into the credentials
> > record.
> >
> > Note that the effective capabilities mask in the cred struct shadows that in
> > the task_struct because a thread can have its capabilities masks changed by
> > another thread. The shadowing is performed by update_current_cred() which is
> > invoked on entry to any system call that might need it.
>
> OOC If we were to simply drop support for one process changing the
> capabilities of another, would we need this patch?

Umm... It would become simpler (which is a damn good thing - less PITA
with update_current_cred), but it would be still needed.

FWIW, dropping that support would be a Good Thing(tm), as far as I'm
concerned. _Why_ do we want that, anyway, and how much userland code
is able to cope with that in sane way?
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