From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Sun, 26 Sep 2010 19:21:44 +0000 (+0100)
Subject: drm/i915: Rephrase pwrite bounds checking to avoid any potential overflow
X-Git-Tag: v2.6.36-rc7~17^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7dcd2499deab8f10011713c40bc2f309c9b65077;p=platform%2Fkernel%2Flinux-3.10.git

drm/i915: Rephrase pwrite bounds checking to avoid any potential overflow

... and do the same for pread.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
---

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7749e78..aa959c4a 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -471,12 +471,8 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,
 		return -ENOENT;
 	obj_priv = to_intel_bo(obj);
 
-	/* Bounds check source.
-	 *
-	 * XXX: This could use review for overflow issues...
-	 */
-	if (args->offset > obj->size || args->size > obj->size ||
-	    args->offset + args->size > obj->size) {
+	/* Bounds check source.  */
+	if (args->offset > obj->size || args->size > obj->size - args->offset) {
 		ret = -EINVAL;
 		goto err;
 	}
@@ -939,12 +935,8 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 		return -ENOENT;
 	obj_priv = to_intel_bo(obj);
 
-	/* Bounds check destination.
-	 *
-	 * XXX: This could use review for overflow issues...
-	 */
-	if (args->offset > obj->size || args->size > obj->size ||
-	    args->offset + args->size > obj->size) {
+	/* Bounds check destination. */
+	if (args->offset > obj->size || args->size > obj->size - args->offset) {
 		ret = -EINVAL;
 		goto err;
 	}