The block layer can't support the block size larger than
page size yet. If an untrusted 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.
Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
---
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);
+ 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
