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From:   Ming Lei <tom.leiming@gmail.com>
Date:   Wed, 15 Jul 2020 18:33:56 +0800
Message-ID: <CACVXFVNu+HjGJUvAEK96TB7pOC=k=p5f0Yg3K6t_13qudDAjjw@mail.gmail.com>
Subject: Re: [PATCH] virtio-blk: check host supplied logical block size
To:     Maxim Levitsky <mlevitsk@redhat.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Jens Axboe <axboe@kernel.dk>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        "open list:VIRTIO CORE AND NET DRIVERS" 
        <virtualization@lists.linux-foundation.org>,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>
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On Wed, Jul 15, 2020 at 5:55 PM Maxim Levitsky <mlevitsk@redhat.com> wrote:
>
> Linux kernel only supports logical block sizes which are power of two,
> at least 512 bytes and no more that PAGE_SIZE.
>
> Check this instead of crashing later on.
>
> Note that there is no need to check physical block size since it is
> only a hint, and virtio-blk already only supports power of two values.
>
> Bugzilla link: https://bugzilla.redhat.com/show_bug.cgi?id=1664619
>
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>  drivers/block/virtio_blk.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 980df853ee497..36dda31cc4e96 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -681,6 +681,12 @@ static const struct blk_mq_ops virtio_mq_ops = {
>  static unsigned int virtblk_queue_depth;
>  module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
>
> +
> +static bool virtblk_valid_block_size(unsigned int blksize)
> +{
> +       return blksize >= 512 && blksize <= PAGE_SIZE && is_power_of_2(blksize);
> +}
> +
>  static int virtblk_probe(struct virtio_device *vdev)
>  {
>         struct virtio_blk *vblk;
> @@ -809,9 +815,16 @@ static int virtblk_probe(struct virtio_device *vdev)
>         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
>                                    struct virtio_blk_config, blk_size,
>                                    &blk_size);
> -       if (!err)
> +       if (!err) {
> +               if (!virtblk_valid_block_size(blk_size)) {
> +                       dev_err(&vdev->dev,
> +                               "%s failure: unsupported logical block size %d\n",
> +                               __func__, blk_size);
> +                       err = -EINVAL;
> +                       goto out_cleanup_queue;
> +               }
>                 blk_queue_logical_block_size(q, blk_size);
> -       else
> +       } else
>                 blk_size = queue_logical_block_size(q);
>
>         /* Use topology information if available */
> @@ -872,6 +885,9 @@ static int virtblk_probe(struct virtio_device *vdev)
>         device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
>         return 0;
>
> +out_cleanup_queue:
> +       blk_cleanup_queue(vblk->disk->queue);
> +       vblk->disk->queue = NULL;
>  out_free_tags:
>         blk_mq_free_tag_set(&vblk->tag_set);
>  out_put_disk:
> --
> 2.26.2
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Looks fine,

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming Lei