From: Xie Yongji <xieyongji@xxxxxxxxxxxxx> commit 57a13a5b8157d9a8606490aaa1b805bafe6c37e1 upstream. 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@xxxxxxxxxxxxx> Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Link: https://lore.kernel.org/r/20211026144015.188-5-xieyongji@xxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/block/virtio_blk.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -849,9 +849,17 @@ static int virtblk_probe(struct virtio_d 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_free_tags; + } + blk_queue_logical_block_size(q, blk_size); - else + } else blk_size = queue_logical_block_size(q); /* Use topology information if available */
