Re: [Qemu-block] [Qemu-devel] [PATCH 1/4] vpc: Check failure of bdrv_getlength()

[Philippe Mathieu-Daudé]

On 08/07/2017 05:30 PM, Eric Blake wrote:
> vpc_open() was checking for bdrv_getlength() failure in one, but
> not the other, location.
>
> Reported-by: Markus Armbruster <address@hidden>
> Signed-off-by: Eric Blake <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>   block/vpc.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/block/vpc.c b/block/vpc.c
> index 574879ba7c..468d10ec1c 100644
> --- a/block/vpc.c
> +++ b/block/vpc.c
> @@ -219,6 +219,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, 
> int flags,
>       uint64_t pagetable_size;
>       int disk_type = VHD_DYNAMIC;
>       int ret;
> +    int64_t bs_size;
>
>       bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
>                                  false, errp);
> @@ -411,7 +412,13 @@ static int vpc_open(BlockDriverState *bs, QDict *options, 
> int flags,
>               }
>           }
>
> -        if (s->free_data_block_offset > bdrv_getlength(bs->file->bs)) {
> +        bs_size = bdrv_getlength(bs->file->bs);
> +        if (bs_size < 0) {
> +            error_setg_errno(errp, -bs_size, "unable to learn image size");
> +            ret = bs_size;
> +            goto fail;
> +        }
> +        if (s->free_data_block_offset > bs_size) {
>               error_setg(errp, "block-vpc: free_data_block_offset points after "
>                                "the end of file. The image has been 
> truncated.");
>               ret = -EINVAL;