[kernel-hardening] Re: [PATCH v4] scripts: add leaking_addresses.pl

["Tobin C. Harding" <me@tobin.cc>]

On Tue, Nov 07, 2017 at 01:56:05PM +0000, David Laight wrote:
> From: Tobin C. Harding
> > Sent: 07 November 2017 10:32
> >
> > Currently we are leaking addresses from the kernel to user space. This
> > script is an attempt to find some of those leakages. Script parses
> > `dmesg` output and /proc and /sys files for hex strings that look like
> > kernel addresses.
> ...
> 
> Maybe the %p that end up in dmesg (via the kernel message buffer) should
> be converted to text in a form that allows the code that reads them to
> substitute alternate text for non-root users?
>
> Then the actual addresses will be available to root (who can probably
> get most by other means) but not to the casual observer.

Interesting idea. Isn't the same outcome already achieved with
dmesg_restrict. I appreciate that this does beg the question 'why are we
scanning dmesg then?'

There has not been much discussion on dmesg_restrict. Is dmesg_restrict
good enough that we needn't bother scanning it?

thanks for your input,
Tobin.