[PATCH 4.9 087/101] video: uvesafb: Fix integer overflow in allocation

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kees Cook <keescook@xxxxxxxxxxxx>

commit 9f645bcc566a1e9f921bdae7528a01ced5bc3713 upstream.

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@xxxxxxxxx>
Fixes: 8bdb3a2d7df48 ("uvesafb: the driver core")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/video/fbdev/uvesafb.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/video/fbdev/uvesafb.c
+++ b/drivers/video/fbdev/uvesafb.c
@@ -1059,7 +1059,8 @@ static int uvesafb_setcmap(struct fb_cma
 		    info->cmap.len || cmap->start < info->cmap.start)
 			return -EINVAL;
 
-		entries = kmalloc(sizeof(*entries) * cmap->len, GFP_KERNEL);
+		entries = kmalloc_array(cmap->len, sizeof(*entries),
+					GFP_KERNEL);
 		if (!entries)
 			return -ENOMEM;