Re: [PATCH] block: Raise an error when backing file parameter is an empty string

[Eric Blake <eblake@redhat.com>]

On 6/17/20 1:27 PM, Connor Kuehl wrote:
> Providing an empty string for the backing file parameter like so:
> 
> 	qemu-img create -f qcow2 -b '' /tmp/foo
> 
> allows the flow of control to reach and subsequently fail an assert
> statement because passing an empty string to
> 
> 	bdrv_get_full_backing_filename_from_filename()
> 
> simply results in NULL being returned without an error being raised.
> 
> To fix this, let's check for an empty string when getting the value from
> the opts list.
> 
> Reported-by: Attila Fazekas <afazekas@redhat.com>
> Fixes: https://bugzilla.redhat.com/1809553
> Signed-off-by: Connor Kuehl <ckuehl@redhat.com>
> ---
>   block.c                    |  4 ++++
>   tests/qemu-iotests/298     | 47 ++++++++++++++++++++++++++++++++++++++
>   tests/qemu-iotests/298.out |  5 ++++
>   tests/qemu-iotests/group   |  1 +
>   4 files changed, 57 insertions(+)
>   create mode 100755 tests/qemu-iotests/298
>   create mode 100644 tests/qemu-iotests/298.out

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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