[linux-fbdev-devel][PATCH]fb_pan_display:add x/yoffset check

[Kai Jiang <b18973@freescale.com>]

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From a01ede69772634b30a83b44eada5a8db66f8463a Mon Sep 17 00:00:00 2001
From: Kai Jiang <Kai.Jiang@freescale.com>
Date: Mon, 29 Jun 2009 11:25:58 +0800
Subject: [PATCH] When moving virtual space straight to one side in the screen(ex.
 straight to the left),finally the virtual space will move outside
 of the real screen. Then the xoffset or yoffset will be nagative
 value(transfered from user application) to indicate that the virtual
 space is beyond the screen boundary. In the function fb_pan_disaplay,
 xoffset and yoffset should be checked to ensure that, when they are
 negative, the virtual space will not move any more,and the function
 will return an error. However, xoffset and yoffset in the structure
 fb_var_screeninfo are "__u32" type, here need to transfer them to
 "int" type for comparing.

Signed-off-by: Kai Jiang <Kai.Jiang@freescale.com>
---
 drivers/video/fbmem.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index d412a1d..27628de 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -855,6 +855,8 @@ fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
 {
 	struct fb_fix_screeninfo *fix = &info->fix;
 	unsigned int yres = info->var.yres;
+	int xoffset = var->xoffset;
+	int yoffset = var->yoffset;
 	int err = 0;
 
 	if (var->yoffset > 0) {
@@ -873,7 +875,8 @@ fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
 
 	if (err || !info->fbops->fb_pan_display ||
 	    var->yoffset + yres > info->var.yres_virtual ||
-	    var->xoffset + info->var.xres > info->var.xres_virtual)
+	    var->xoffset + info->var.xres > info->var.xres_virtual ||
+	    xoffset < 0 || yoffset < 0)
 		return -EINVAL;
 
 	if ((err = info->fbops->fb_pan_display(var, info)))
-- 
1.6.2.1


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