From 82e89ea077b93b3c131fa175b0df3acb5b1d5cdf Mon Sep 17 00:00:00 2001 From: Xie Yongji Date: Mon, 9 Aug 2021 18:16:09 +0800 Subject: virtio-blk: Add validation for block size in config space 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 Link: https://lore.kernel.org/r/20210809101609.148-1-xieyongji@bytedance.com Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang --- 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); + + 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, -- cgit v1.2.3