Re: [Qemu-devel] [PATCH for-4.0-maybe] device_tree: Fix integer overflowing in load_device_tree()

[Peter Maydell]

On Tue, 9 Apr 2019 at 21:15, Alistair Francis <address@hidden> wrote:
>
> On Tue, Apr 9, 2019 at 1:08 PM Peter Maydell <address@hidden> wrote:
> >
> > On Wed, 10 Apr 2019 at 00:40, Markus Armbruster <address@hidden> wrote:
> > >
> > > If the value of get_image_size() exceeds INT_MAX / 2 - 10000, the
> > > computation of @dt_size overflows to a negative number, which then
> > > gets converted to a very large size_t for g_malloc0() and
> > > load_image_size().  In the (fortunately improbable) case g_malloc0()
> > > succeeds and load_image_size() survives, we'd assign the negative
> > > number to *sizep.  What that would do to the callers I can't say, but
> > > it's unlikely to be good.
> > >
> > > Fix by rejecting images whose size would overflow.
> > >
> > > Signed-off-by: Markus Armbruster <address@hidden>
> >
> > I think this patch is missing some attributions for the
> > security researchers who found the issue initially.
> > PJP's patch for this from a couple of weeks back has a
> > reported-by credit:
> > https://patchew.org/QEMU/address@hidden/
>
> It seems like from that discussion that this patch is the correct approach.
>
> I can add the attributions and send a PR for 4.0. I'll send it by EOD
> unless anyone has any objections.

Thanks. I think given it's 21:30 here I'm going to postpone
tagging rc3 til tomorrow (mid-afternoon UK time). I'm still
hoping we can avoid an rc4...

thanks
-- PMM