From: Colin Cross <ccross@android.com>
Date: Wed, 13 Nov 2013 22:44:53 +0000 (-0800)
Subject: ion: fix crash when alloc len is -1
X-Git-Tag: firefly_0821_release~4090^2~470
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=49bdc418a3c1129d49fe92d89cf77111584fb51f;p=firefly-linux-kernel-4.4.55.git

ion: fix crash when alloc len is -1

If userspace passes a length between -4095 and -1 to allocate it
will pass the len != 0 check, but when len is page aligned it will
be 0.  Check len after page aligning.

Drop the warning as well, userspace shouldn't be able to trigger
a warning in the kernel.

Change-Id: I96c7142637638991f3a9af9be7cfbb50f79f3803
Signed-off-by: Colin Cross <ccross@android.com>
---

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 0e379a338105..a8d4735b462c 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -485,11 +485,11 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
 	 * request of the caller allocate from it.  Repeat until allocate has
 	 * succeeded or all heaps have been tried
 	 */
-	if (WARN_ON(!len))
-		return ERR_PTR(-EINVAL);
-
 	len = PAGE_ALIGN(len);
 
+	if (!len)
+		return ERR_PTR(-EINVAL);
+
 	down_read(&dev->lock);
 	plist_for_each_entry(heap, &dev->heaps, node) {
 		/* if the caller didn't specify this heap id */