patch "video: fbdev: fix OOB read in vga_8planes_imageblit()" added to char-misc-linus

This is a note to let you know that I've just added the patch titled

video: fbdev: fix OOB read in vga_8planes_imageblit()

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From bd018a6a75cebb511bb55a0e7690024be975fe93 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <[email protected]>
Date: Mon, 31 Aug 2020 19:37:00 +0900
Subject: video: fbdev: fix OOB read in vga_8planes_imageblit()

syzbot is reporting OOB read at vga_8planes_imageblit() [1], for "cdat[y] >> 4" can become a negative value due to "const char *cdat".

[1] https://syzkaller.appspot.com/bug?id=0d7a0da1557dcd1989e00cb3692b26d4173b4132

---
 drivers/video/fbdev/vga16fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index a20eeb8308ff..578d3541e3d6 100644
@@ -1121,7 +1121,7 @@ static void vga_8planes_imageblit(struct fb_info *info, const struct fb_image *i
         char oldop = setop(0);
         char oldsr = setsr(0);
         char oldmask = selectmask();
-        const char *cdat = image->data;
+	const unsigned char *cdat = image->data;
 	u32 dx = image->dx;
         char __iomem *where;
         int y;

2.28.0