On Tue, Apr 09, 2019 at 08:59:55PM +0200, Philippe Mathieu-Daudé wrote:
> On 4/9/19 7:40 PM, Markus Armbruster 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 <arm...@redhat.com>
> > ---
> > device_tree.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/device_tree.c b/device_tree.c
> > index 296278e12a..f8b46b3c73 100644
> > --- a/device_tree.c
> > +++ b/device_tree.c
> > @@ -84,6 +84,10 @@ void *load_device_tree(const char *filename_path, int
> > *sizep)
> > filename_path);
> > goto fail;
> > }
> > + if (dt_size > INT_MAX / 2 - 10000) {
>
> We should avoid magic number duplication.
> That said, this patch looks safe.
>
> Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
As Philippe says, the test condition is kinda ugly and I hope we can
refine it in future. But since it fixes a real problem for now,
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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