[PATCH 4.9 008/218] virtio-blk: Use blk_validate_block_size() to validate block size

Greg Kroah-Hartman
2022-04-18T14:08:11Z

From: Xie Yongji <xieyongji@bytedance.com>

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@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>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -692,9 +692,17 @@ 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 */