Re: [PATCH] use %pK for /proc/kallsyms and /proc/modules

From: Kees Cook
Date: Wed Jan 26 2011 - 19:29:54 EST


On Wed, Jan 26, 2011 at 03:57:06PM -0800, Andrew Morton wrote:
> On Tue, 25 Jan 2011 10:10:58 -0800
> Kees Cook <kees.cook@xxxxxxxxxxxxx> wrote:
> > Instead of messing with permissions on these files,
> This implies that the patch alters permission handling, only it
> doesn't. But I worked it out!

Ah yeah, this was related to the earlier attempts to remove the contents
of, or set permissions on, /proc/kallsyms.

> > Note that this changes %x to %p, so some legitimately 0 values in
> > /proc/kallsyms would have changed from 00000000 to "(null)". To avoid
> > this, "(null)" is not used when using the "K" format. Anything parsing
> > such addresses should have no problem with this change. (Thanks to Joe
> > Perches for the suggestion.)
> OK, so what applications did this patch just break?

I'm not aware of any breakage as a result of this yet.


Kees Cook
Ubuntu Security Team
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