Re: [Qemu-devel] [PATCH v7 08/13] qcow2: Fix refcount blocks beyond image end

[Kevin Wolf]

Am 22.10.2014 um 10:08 hat Max Reitz geschrieben:
> If the qcow2 check function detects a refcount block located beyond the
> image end, grow the image appropriately. This cannot break anything and
> is the logical fix for such a case.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  block/qcow2-refcount.c | 63 
> ++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 59 insertions(+), 4 deletions(-)
> 
> diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
> index d484029..3800d3c 100644
> --- a/block/qcow2-refcount.c
> +++ b/block/qcow2-refcount.c
> @@ -1544,7 +1544,8 @@ static int check_refblocks(BlockDriverState *bs, 
> BdrvCheckResult *res,
>                             int64_t *nb_clusters)
>  {
>      BDRVQcowState *s = bs->opaque;
> -    int64_t i;
> +    int64_t i, size;
> +    int ret;
>  
>      for(i = 0; i < s->refcount_table_size; i++) {
>          uint64_t offset, cluster;
> @@ -1560,9 +1561,63 @@ static int check_refblocks(BlockDriverState *bs, 
> BdrvCheckResult *res,
>          }
>  
>          if (cluster >= *nb_clusters) {
> -            fprintf(stderr, "ERROR refcount block %" PRId64
> -                    " is outside image\n", i);
> -            res->corruptions++;
> +            fprintf(stderr, "%s refcount block %" PRId64 " is outside 
> image\n",
> +                    fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
> +
> +            if (fix & BDRV_FIX_ERRORS) {
> +                int64_t old_nb_clusters = *nb_clusters;
> +
> +                if (offset + s->cluster_size < offset ||
> +                    offset > INT64_MAX - s->cluster_size)

Do you still need the first condition with the reworked second one?

> +                {
> +                    ret = -EINVAL;
> +                    goto resize_fail;
> +                }

Kevin