Re: [PATCH] block/amend: Check whether the node exists

[Maxim Levitsky <mlevitsk@redhat.com>]

On Fri, 2020-07-10 at 11:50 +0200, Max Reitz wrote:
> We should check whether the user-specified node-name actually refers to
> a node.  The simplest way to do that is to use bdrv_lookup_bs() instead
> of bdrv_find_node() (the former wraps the latter, and produces an error
> message if necessary).
> 
> Reported-by: Coverity (CID 1430268)
> Fixes: ced914d0ab9fb2c900f873f6349a0b8eecd1fdbe
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/amend.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/block/amend.c b/block/amend.c
> index f4612dcf08..392df9ef83 100644
> --- a/block/amend.c
> +++ b/block/amend.c
> @@ -69,8 +69,12 @@ void qmp_x_blockdev_amend(const char *job_id,
>      BlockdevAmendJob *s;
>      const char *fmt = BlockdevDriver_str(options->driver);
>      BlockDriver *drv = bdrv_find_format(fmt);
> -    BlockDriverState *bs = bdrv_find_node(node_name);
> +    BlockDriverState *bs;
>  
> +    bs = bdrv_lookup_bs(NULL, node_name, errp);
> +    if (!bs) {
> +        return;
> +    }
>  
>      if (!drv) {
>          error_setg(errp, "Block driver '%s' not found or not supported", fmt);

Yep, this looks like a real bug, sorry about that.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky