Re: [PATCH net] vhost: Use kzalloc() to allocate vhost_msg_node

[Michael S. Tsirkin]

On Fri, Apr 27, 2018 at 11:45:02AM -0400, Kevin Easton wrote:
> The struct vhost_msg within struct vhost_msg_node is copied to userspace,
> so it should be allocated with kzalloc() to ensure all structure padding
> is zeroed.
> 
> Signed-off-by: Kevin Easton <kevin@xxxxxxxxxxx>
> Reported-by: syzbot+87cfa083e727a224754b@xxxxxxxxxxxxxxxxxxxxxxxxx

Does it help if a patch naming the padding is applied,
and then we init just the relevant field?
Just curious.

> ---
>  drivers/vhost/vhost.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f3bd8e9..1b84dcff 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2339,7 +2339,7 @@ EXPORT_SYMBOL_GPL(vhost_disable_notify);
>  /* Create a new message. */
>  struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
>  {
> -	struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
> +	struct vhost_msg_node *node = kzalloc(sizeof *node, GFP_KERNEL);
>  	if (!node)
>  		return NULL;
>  	node->vq = vq;
> -- 
> 2.8.1