Re: [PATCH][LSM] Early init for security modules and various

[Stephen Smalley]

On Mon, 2003-06-02 at 06:44, Andrew Morton wrote:
> Chris Wright <[e-mail]> wrote:
> >
> > security_capable() returns 0 if that capability bit is set. 
> 
> That's just bizarre.  Is there any logic behind it?

The LSM access control hooks all return 0 on success (i.e. permission
granted) and negative error code on failure, like most of the rest of
the kernel interfaces (e.g. consider permission()).  Hence, the
security_capable() hook returns 0 when the capability is granted to the
specified task.  Naturally, the capable() function (which now internally
calls security_capable) preserves the old interface, and most callers
still invoke it rather than directly calling security_capable(). 
However, the oom killer code is performing a capability test for a task
other than current; hence, it makes a direct call to the
security_capable() hook that supports passing a particular task, unlike
the capable() function.

-- 
Stephen Smalley <[e-mail]>
National Security Agency