[PATCH 4.2.y-ckt 208/268] Drivers: hv: utils: use memdup_user in hvt_op_write

[Kamal Mostafa]

4.2.8-ckt3 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Olaf Hering <olaf at aepfle.de>

commit b00359642c2427da89dc8f77daa2c9e8a84e6d76 upstream.

Use memdup_user to handle OOM.

Fixes: 14b50f80c32d ('Drivers: hv: util: introduce hv_utils_transport abstraction')

Signed-off-by: Olaf Hering <olaf at aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/hv/hv_utils_transport.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c
index 1505ee6..24b2766 100644
--- a/drivers/hv/hv_utils_transport.c
+++ b/drivers/hv/hv_utils_transport.c
@@ -80,11 +80,10 @@ static ssize_t hvt_op_write(struct file *file, const char __user *buf,
 
 	hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-	inmsg = kzalloc(count, GFP_KERNEL);
-	if (copy_from_user(inmsg, buf, count)) {
-		kfree(inmsg);
-		return -EFAULT;
-	}
+	inmsg = memdup_user(buf, count);
+	if (IS_ERR(inmsg))
+		return PTR_ERR(inmsg);
+
 	if (hvt->on_msg(inmsg, count))
 		return -EFAULT;
 	kfree(inmsg);
-- 
1.9.1