Re: [PATCH 3/3] x86: kernel base offset ASLR

[Julien Tinnes]

On Fri, Apr 5, 2013 at 7:49 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Thu, Apr 04, 2013 at 01:07:35PM -0700, Kees Cook wrote:
>> This creates CONFIG_RANDOMIZE_BASE, so that the base offset of the kernel
>> can be randomized at boot.
>
> Right,
>
> if I'm reading this whole deal correctly, I have an issue with this
> in the sense that if this thing is enabled by default and people are
> running stripped kernels, an oops which is being reported is worth sh*t
> since all the addresses there are random and one simply can't map them
> back to which functions the callstack frames are pointing to. Which will
> majorly hinder debuggability, IMHO...

I think it'd be perfectly ok for OOPS to print out the kernel base.

Restricting access to these oopses becomes a different problem
(privilege separation). Some existing sandboxes (Chromium, vsftpd,
openssh..) are already defending against it.

Julien
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