在 2021/8/9 下午6:16, Xie Yongji 写道:
An untrusted device might presents an invalid block size
in configuration space. This tries to add validation for it
in the validate callback and clear the VIRTIO_BLK_F_BLK_SIZE
feature bit if the value is out of the supported range.
And we also double check the value in virtblk_probe() in
case that it's changed after the validation.
Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
---
drivers/block/virtio_blk.c | 39 +++++++++++++++++++++++++++++++++------
1 file changed, 33 insertions(+), 6 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 4b49df2dfd23..afb37aac09e8 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -692,6 +692,28 @@ 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 int virtblk_validate(struct virtio_device *vdev)
+{
+ u32 blk_size;
+
+ if (!vdev->config->get) {
+ dev_err(&vdev->dev, "%s failure: config access disabled\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ if (!virtio_has_feature(vdev, VIRTIO_BLK_F_BLK_SIZE))
+ return 0;
+
+ blk_size = virtio_cread32(vdev,
+ offsetof(struct virtio_blk_config, blk_size));
+
+ if (blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE)
+ __virtio_clear_bit(vdev, VIRTIO_BLK_F_BLK_SIZE);
I wonder if it's better to just fail here as what we did for probe().
Thanks
+
+ return 0;
+}
+
static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
@@ -703,12 +725,6 @@ static int virtblk_probe(struct virtio_device *vdev)
u8 physical_block_exp, alignment_offset;
unsigned int queue_depth;
- if (!vdev->config->get) {
- dev_err(&vdev->dev, "%s failure: config access disabled\n",
- __func__);
- return -EINVAL;
- }
-
err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
GFP_KERNEL);
if (err < 0)
@@ -823,6 +839,14 @@ static int virtblk_probe(struct virtio_device *vdev)
else
blk_size = queue_logical_block_size(q);
+ if (unlikely(blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE)) {
+ dev_err(&vdev->dev,
+ "block size is changed unexpectedly, now is %u\n",
+ blk_size);
+ err = -EINVAL;
+ goto err_cleanup_disk;
+ }
+
/* Use topology information if available */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, physical_block_exp,
@@ -881,6 +905,8 @@ static int virtblk_probe(struct virtio_device *vdev)
device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
return 0;
+err_cleanup_disk:
+ blk_cleanup_disk(vblk->disk);
out_free_tags:
blk_mq_free_tag_set(&vblk->tag_set);
out_free_vq:
@@ -983,6 +1009,7 @@ static struct virtio_driver virtio_blk = {
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
+ .validate = virtblk_validate,
.probe = virtblk_probe,
.remove = virtblk_remove,
.config_changed = virtblk_config_changed,
