[PATCH 086/115] ion: fix crash when alloc len is -1

John Stultz
2013-12-13T22:28:28Z

From: Colin Cross <ccross@android.com>

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.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/staging/android/ion/ion.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index cf9fc78..2e7be70 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 */
--
1.8.3.2