Re: CVS commit: src

[David Holland <dholland-sourcechanges%netbsd.org@localhost>]

On Wed, Aug 26, 2009 at 12:23:39AM -0400, Elad Efrat wrote:
> Unrelated to the topic of the thread, but kmem(9) says:
>
> SECURITY CONSIDERATION
>      As the memory allocated by kmem_alloc() is uninitialized, it can
>      contain security-sensitive data left by its previous user.  It is
>      the caller's responsibility not to expose it to the world.
>
> Shouldn't it be the responsibility of the security-sensitive subsystem
> to clear the memory before it is freed, rather than the responsibility
> of every kmem_alloc() caller?

All recycled kernel memory, including stack frames, is considered
security-sensitive and not supposed to be exposed to the world. (Given
that you're working on the security system, you ought to know this.)
It is a matter of proper copyout() usage.

-- 
David A. Holland
dholland%netbsd.org@localhost