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Date: Mon, 7 Aug 2017 19:32:12 -0400
From: Jeff Cody <jcody@redhat.com>
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References: <20170807203007.19033-1-eblake@redhat.com>
	<20170807203007.19033-2-eblake@redhat.com>
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Subject: Re: [Qemu-devel] [Qemu-block] [PATCH 1/4] vpc: Check failure of
 bdrv_getlength()
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To: Eric Blake <eblake@redhat.com>
Cc: qemu-devel@nongnu.org, kwolf@redhat.com, armbru@redhat.com, qemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>

On Mon, Aug 07, 2017 at 03:30:04PM -0500, Eric Blake wrote:
> vpc_open() was checking for bdrv_getlength() failure in one, but
> not the other, location.
> 
> Reported-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  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;
> -- 
> 2.13.4
> 
> 

Reviewed-by: Jeff Cody <jcody@redhat.com>