Re: [PATCH 0/6] MODSIGN: Kernel module signing

David Lang
2007-02-15T20:17:13Z

On Thu, 15 Feb 2007, Roman Zippel wrote:

> On Thu, 15 Feb 2007, David Howells wrote:
>
>> It is possible to protect /dev/mem and /dev/kmem or make them unavailable and
>> it is possible to protect the kernel's memory whilst it is running (provided
>> you don't have nommu or broken hardware and you don't let userspace concoct any
>> DMA request it likes) which mostly closes those other vectors I mentioned.
>> This isn't something I intended to look at with this patch. Those are separate
>> holes.
>
> Exactly and as long as there are these holes, these patches are only
> kernel bloat. The simple verification can also be done in userspace and
> module signing offers no real security.
> What real value do these patches provide, that can't be reached via other
> means? Who else than distributions would be interested in this? Pretty
> much any use you initially mentioned can be done in simpler ways, e.g.
> anyone afraid of modules simply disables module loading completely.

this issue, and these holes keep comeing up in discussions, why can't these
holes be closed? I seem to remember seeing patches that would remove /dev/kmem
being sent to the list, but they weren't accepted into the kernel (and I seem to
remember people being against the concept of removeing them, not against
techincal details of the patches. but this was many years ago)

at one point I remember hearing that X required raw /dev/kmem, but for servers
you don't need/want X anyway, so this is a useful option even if X doesn't get
fixed.

David Lang