Virtualization - Jun 2018 - KMSAN: uninit-value in _copy_to_iter (2)

#syz test: https://github.com/google/kmsan.git master

Subject: vhost: fix info leak

Fixes: CVE-2018-1118
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index f0be5f35ab28..9beefa6ed1ce 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2345,6 +2345,9 @@ struct vhost_msg_node *vhost_new_msg(struct
vhost_virtqueue *vq, int type)
 	struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
 	if (!node)
 		return NULL;
+
+	/* Make sure all padding within the structure is initialized. */
+	memset(&node->msg, 0, sizeof node->msg);
 	node->vq = vq;
 	node->msg.type = type;
 	return node;