video: uvesafb: Fix integer overflow in allocation

video: uvesafb: Fix integer overflow in allocation

CVE-2018-13406

cmap->len can get close to INT_MAX/2, allowing for an integer overflow in
allocation. This uses kmalloc_array() instead to catch the condition.

Reported-by: Dr Silvio Cesare of InfoSect <silvio.cesare@gmail.com>
Fixes: 8bdb3a2d7df48 ("uvesafb: the driver core")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
(cherry picked from commit 9f645bcc566a1e9f921bdae7528a01ced5bc3713)
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>