From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Tobin C. Harding" <me@tobin.cc>
Subject: Re: [PATCH v4] scripts: add leaking_addresses.pl
Date: Wed, 8 Nov 2017 07:58:20 +1100
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Cc: "kernel-hardening@lists.openwall.com"
        <kernel-hardening@lists.openwall.com>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Theodore Ts'o <tytso@mit.edu>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
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        Tycho Andersen <tycho@docker.com>,
        "Roberts, William C" <william.c.roberts@intel.com>,
        Tejun Heo <tj@kernel.org>,
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        Petr Mladek <pmladek@suse.com>, Joe Perches <joe@perches.com>,
        Ian Campbell <ijc@hellion.org.uk>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
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        Steven Rostedt <rostedt@goodmis.org>,
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To: David Laight <David.Laight@ACULAB.COM>
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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.