virtio-blk: Use blk_validate_block_size() to validate block size

The block layer can't support a block size larger than
page size yet. And a block size that's too small or
not a power of two won't work either. If a misconfigured
device presents an invalid block size in configuration space,
it will result in the kernel crash something like below:

[  506.154324] BUG: kernel NULL pointer dereference, address: 0000000000000008
[  506.160416] RIP: 0010:create_empty_buffers+0x24/0x100
[  506.174302] Call Trace:
[  506.174651]  create_page_buffers+0x4d/0x60
[  506.175207]  block_read_full_page+0x50/0x380
[  506.175798]  ? __mod_lruvec_page_state+0x60/0xa0
[  506.176412]  ? __add_to_page_cache_locked+0x1b2/0x390
[  506.177085]  ? blkdev_direct_IO+0x4a0/0x4a0
[  506.177644]  ? scan_shadow_nodes+0x30/0x30
[  506.178206]  ? lru_cache_add+0x42/0x60
[  506.178716]  do_read_cache_page+0x695/0x740
[  506.179278]  ? read_part_sector+0xe0/0xe0
[  506.179821]  read_part_sector+0x36/0xe0
[  506.180337]  adfspart_check_ICS+0x32/0x320
[  506.180890]  ? snprintf+0x45/0x70
[  506.181350]  ? read_part_sector+0xe0/0xe0
[  506.181906]  bdev_disk_changed+0x229/0x5c0
[  506.182483]  blkdev_get_whole+0x6d/0x90
[  506.183013]  blkdev_get_by_dev+0x122/0x2d0
[  506.183562]  device_add_disk+0x39e/0x3c0
[  506.184472]  virtblk_probe+0x3f8/0x79b [virtio_blk]
[  506.185461]  virtio_dev_probe+0x15e/0x1d0 [virtio]

So let's use a block layer helper to validate the block size.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20211026144015.188-5-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 303caf2..fd08617 100644 (file)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -815,9 +815,17 @@ 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) {
+               err = blk_validate_block_size(blk_size);
+               if (err) {
+                       dev_err(&vdev->dev,
+                               "virtio_blk: invalid block size: 0x%x\n",
+                               blk_size);
+                       goto out_cleanup_disk;
+               }
+
                blk_queue_logical_block_size(q, blk_size);
-       else
+       } else
                blk_size = queue_logical_block_size(q);
 
        /* Use topology information if available */