[PATCH v6 01/12] media: platform: mtk-mdp3: fix potential frame size overflow in mdp_try_fmt_mplane()

[Moudy Ho]

Fix overflow risk when setting certain formats whose frame size exceeds
a RGB24 with 7723x7723 resolution.

For example, a 7723x7724 RGB24 frame:
    1. bpl (byte per line) = 7723 * 3.
    2. Overflow occurs when bpl * 7724 * depth.

Fixes: 61890ccaefaf ("media: platform: mtk-mdp3: add MediaTek MDP3 driver")
Signed-off-by: Moudy Ho <moudy.ho at mediatek.com>
---
 drivers/media/platform/mediatek/mdp3/mtk-mdp3-regs.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-regs.c b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-regs.c
index 4e84a37ecdfc..36336d169bd9 100644
--- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-regs.c
+++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-regs.c
@@ -4,6 +4,7 @@
  * Author: Ping-Hsun Wu <ping-hsun.wu at mediatek.com>
  */
 
+#include <linux/math64.h>
 #include <media/v4l2-common.h>
 #include <media/videobuf2-v4l2.h>
 #include <media/videobuf2-dma-contig.h>
@@ -428,14 +429,15 @@ const struct mdp_format *mdp_try_fmt_mplane(struct v4l2_format *f,
 		u32 bpl = pix_mp->plane_fmt[i].bytesperline;
 		u32 min_si, max_si;
 		u32 si = pix_mp->plane_fmt[i].sizeimage;
+		u64 di;
 
 		bpl = clamp(bpl, min_bpl, max_bpl);
 		pix_mp->plane_fmt[i].bytesperline = bpl;
 
-		min_si = (bpl * pix_mp->height * fmt->depth[i]) /
-			 fmt->row_depth[i];
-		max_si = (bpl * s.max_height * fmt->depth[i]) /
-			 fmt->row_depth[i];
+		di = (u64)bpl * pix_mp->height * fmt->depth[i];
+		min_si = (u32)div_u64(di, fmt->row_depth[i]);
+		di = (u64)bpl * s.max_height * fmt->depth[i];
+		max_si = (u32)div_u64(di, fmt->row_depth[i]);
 
 		si = clamp(si, min_si, max_si);
 		pix_mp->plane_fmt[i].sizeimage = si;
-- 
2.18.0