[PATCH] vga16fb: test virtual screen range before subtraction onunsigned

From: Roel Kluin
Date: Wed Apr 23 2008 - 13:21:18 EST


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

Signed-off-by: Roel Kluin <12o3l@xxxxxxxxxx>
---
diff --git a/drivers/video/vga16fb.c b/drivers/video/vga16fb.c
index 9b3c592..9d27517 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) {
--
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