From: Roel Kluin <12o3l@tiscali.nl>
Date: Thu, 24 Jul 2008 04:31:19 +0000 (-0700)
Subject: vga16fb: test virtual screen range before subtraction on unsigned
X-Git-Tag: v2.6.27-rc1~566
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=77a6e7abb09de0e85a15e2fe42c21ffc59847759;p=linux-2.6

vga16fb: test virtual screen range before subtraction on unsigned

dx and dy are u32's, so the test should occur before the subtraction

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
Cc: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/video/vga16fb.c b/drivers/video/vga16fb.c
index 9b3c592336..9d27517178 100644
--- a/drivers/video/vga16fb.c
+++ b/drivers/video/vga16fb.c
@@ -1087,12 +1087,15 @@ static void vga16fb_copyarea(struct fb_info *info, const struct fb_copyarea *are
 	width = x2 - dx;
 	height = y2 - dy;
 
+	if (sx + dx < old_dx || sy + dy < old_dy)
+		return;
+
 	/* update sx1,sy1 */
 	sx += (dx - old_dx);
 	sy += (dy - old_dy);
 
 	/* the source must be completely inside the virtual screen */
-	if (sx < 0 || sy < 0 || (sx + width) > vxres || (sy + height) > vyres)
+	if (sx + width > vxres || sy + height > vyres)
 		return;
 
 	switch (info->fix.type) {