linux-kernel - [PATCH] virtio-blk: check host supplied logical block size

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Date:   Wed, 15 Jul 2020 12:55:18 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Stefan Hajnoczi <stefanha@...hat.com>,
        linux-block@...r.kernel.org (open list:BLOCK LAYER),
        virtualization@...ts.linux-foundation.org (open list:VIRTIO CORE AND
        NET DRIVERS), Paolo Bonzini <pbonzini@...hat.com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>, Jens Axboe <axboe@...nel.dk>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH] virtio-blk: check host supplied logical block size

Linux kernel only supports logical block sizes which are power of two,
at least 512 bytes and no more that PAGE_SIZE.

Check this instead of crashing later on.

Note that there is no need to check physical block size since it is
only a hint, and virtio-blk already only supports power of two values.

Bugzilla link: https://bugzilla.redhat.com/show_bug.cgi?id=1664619

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 drivers/block/virtio_blk.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 980df853ee497..36dda31cc4e96 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -681,6 +681,12 @@ static const struct blk_mq_ops virtio_mq_ops = {
 static unsigned int virtblk_queue_depth;
 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
 
+
+static bool virtblk_valid_block_size(unsigned int blksize)
+{
+	return blksize >= 512 && blksize <= PAGE_SIZE && is_power_of_2(blksize);
+}
+
 static int virtblk_probe(struct virtio_device *vdev)
 {
 	struct virtio_blk *vblk;
@@ -809,9 +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) {
+		if (!virtblk_valid_block_size(blk_size)) {
+			dev_err(&vdev->dev,
+				"%s failure: unsupported logical block size %d\n",
+				__func__, blk_size);
+			err = -EINVAL;
+			goto out_cleanup_queue;
+		}
 		blk_queue_logical_block_size(q, blk_size);
-	else
+	} else
 		blk_size = queue_logical_block_size(q);
 
 	/* Use topology information if available */
@@ -872,6 +885,9 @@ static int virtblk_probe(struct virtio_device *vdev)
 	device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
 	return 0;
 
+out_cleanup_queue:
+	blk_cleanup_queue(vblk->disk->queue);
+	vblk->disk->queue = NULL;
 out_free_tags:
 	blk_mq_free_tag_set(&vblk->tag_set);
 out_put_disk:
-- 
2.26.2