Re: RFC: Tainting the kernel on raw I/O access

[Matthew Garrett]

(Cc: Kees)

On Wed, Sep 03, 2014 at 02:20:59PM -0700, H. Peter Anvin wrote:
> In a meeting earlier today, we discussed MSR access and that it could be
> used to do bad things.  The same applies to other forms of raw I/O
> (/dev/mem, /dev/port, ioperm, iopl, etc.)
> 
> This is basically the same problem with which the secure boot people
> have been struggling.
> 
> Peter Z. suggested we should taint the kernel on raw I/O access, and I
> tend to concur.
> 
> So what I would like to suggest is that we create a new kernel helper
> function which can return an error in secure boot mode and otherwise
> taints the kernel with a raw I/O taint.
> 
> What do people think?

Not a bad plan, but there's a couple of places where you'd want to 
forbid stuff in Secure Boot without tainting the kernel in the generic 
use-case, so there's still some problem to solve there.

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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