Michael S. Tsirkin
2021-Oct-25 17:08 UTC
[PATCH v2 4/4] virtio-blk: Use blk_validate_block_size() to validate block size
On Mon, Oct 25, 2021 at 10:25:06PM +0800, Xie Yongji wrote:> The block layer can't support the block size larger thanthe block size -> block sizes, or a block size> page size yet.And to add to that, a block size that's too small or not a power of two won't work either, right? Mention that too.> If an untrusted devicenothing to do with trust. 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 this patch tries to use the block layer helper to > validate the block size.I know you are trying to be polite but it's misplaced here. Just say what it is: Use a block layer helper to validate the block size.> > Signed-off-by: Xie Yongji <xieyongji at bytedance.com> > --- > drivers/block/virtio_blk.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 303caf2d17d0..8b5833997f8e 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -815,9 +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) { > + err = blk_validate_block_size(blk_size); > + if (err) { > + dev_err(&vdev->dev, > + "get invalid block size: %u\n", blk_size);Probably hex. Add virtio_blk: and drop "get" here - it's ungrammatical. "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 */ > -- > 2.11.0