Re: [PATCH] firmware: make sure paths remain relative

From: Kees Cook
Date: Mon Dec 17 2012 - 21:03:33 EST


On Mon, Dec 17, 2012 at 5:30 PM, Ming Lei <ming.lei@xxxxxxxxxxxxx> wrote:
> On Sat, Dec 15, 2012 at 6:51 AM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>> Some devices have configurable firmware locations. If these configuration
>> mechanisms are exposed to unprivileged userspace, it may be possible to
>
> I an wondering how the unprivileged userspace can write the firmware sysfs
> to trigger loading firmware?

If a daemon were to, for example, make firmware selectable by the user
(which under certain situations is possible in Chrome OS), it seems
wasteful require these userspace tools/interfaces to each perform
filtering, so I figured it would be trivial to put in here instead to
avoid possible future vulnerabilities.

-Kees

--
Kees Cook
Chrome OS Security
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