[media] V4L: mx2-camera: avoid overflowing 32-bits

In mx2_camera_try_fmt(), when applying i.MX25 restrictions to frame sizes,
the height is checked to be <= 0xffff. But later an integer multiplication
height * 4 * 0x3ffff is performed, which will overflow even for bounded
height values. This patch switches to using 64-bit multiplication and
division to avoid overflowing.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/mx2_camera.c b/drivers/media/video/mx2_camera.c
index ecd83faf90380fbec2389e53b725ac605df2903f..ded26b7286faaea01bac1220dfc9c4ea8a0a273b 100644 (file)
--- a/drivers/media/video/mx2_camera.c
+++ b/drivers/media/video/mx2_camera.c
@@ -22,6 +22,7 @@
 #include <linux/gcd.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/math64.h>
 #include <linux/mm.h>
 #include <linux/moduleparam.h>
 #include <linux/time.h>
@@ -1400,8 +1401,8 @@ static int mx2_camera_try_fmt(struct soc_camera_device *icd,
                /* Check against the CSIRXCNT limit */
                if (pix->sizeimage > 4 * 0x3ffff) {
                        /* Adjust geometry, preserve aspect ratio */
-                       unsigned int new_height = int_sqrt(4 * 0x3ffff *
-                                       pix->height / pix->bytesperline);
+                       unsigned int new_height = int_sqrt(div_u64(0x3ffffULL *
+                                       4 * pix->height, pix->bytesperline));
                        pix->width = new_height * pix->width / pix->height;
                        pix->height = new_height;
                        pix->bytesperline = soc_mbus_bytes_per_line(pix->width,