Re: [RESEND][PATCH] gen_init_cpio: avoid stack overflow when expanding

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 24 Oct 2012 14:53:33 -0700
Kees Cook <keescook@chromium.org> wrote:

> > Well, I do think that a description of the user impact of the bug
> > should be included in the changelog so that poor old Greg can work out
> > why we sent it at him.
> >
> > If you can suggest some suitable text I can copy-n-slurp that into the
> > changelog.
> 
> How about replacing the first paragraph with:
> 
> Fix possible overflow of the buffer used for expanding environment
> variables when building file list. In the extremely unlikely case of
> an attacker having control over the environment variables visible to
> gen_init_cpio, control over the contents of the file gen_init_cpio
> parses, and gen_init_cpio was built without compiler hardening, the
> attacker can gain arbitrary execution control via a stack buffer
> overflow.

ooh, spiffy - even I understood that!