Re: Do not allow MSR or Embedded Controller writes from userspace in secure boot case

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Nov 08, 2012 at 10:40:33AM +0100, Thomas Renninger wrote:
> On Wednesday, November 07, 2012 09:54:03 PM Matthew Garrett wrote:
> > Is there a case where modifying MSRs or EC registers can cause arbitrary
> > code execution?
> 
> Ok, I am not familiar enough with this secure stuff.
> Theoretically writing EC registers could be used to trick ACPI
> code and change the way it is processed by inspecting ACPI
> code for bad EC register return values.

I'd prefer to see an actual example before worrying too much about this.

> Similar for MSR, the kernel could be (not directly) influenced
> by setting MSR registers in a way it does not expect them to be.

Again, I'd like to see an example of arbitrary code execution.

> I expect it's easy to get the system totally stalled/hang/rebooted
> with bad MSR writes which I thought should be forbidden for
> userspace (even for root...) in secure boot mode.

root can call halt, which is a trivial DoS. It's not worth worrying 
about people wedging the system.

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux