Re: [PATCH V2 01/12] virtio-blk: validate num_queues during probe
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-10-13 10:04:52
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On Tue, Oct 12, 2021 at 02:52:16PM +0800, Jason Wang wrote:
If an untrusted device neogitates BLK_F_MQ but advertises a zero num_queues, the driver may end up trying to allocating zero size buffers where ZERO_SIZE_PTR is returned which may pass the checking against the NULL. This will lead unexpected results. Fixing this by using single queue if num_queues is zero. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Jason Wang <redacted>
I'd rather fail probe so we don't need to support that.
quoted hunk ↗ jump to hunk
--- drivers/block/virtio_blk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 9b3bd083b411..9deff01a38cb 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c@@ -495,7 +495,8 @@ static int init_vq(struct virtio_blk *vblk) err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, struct virtio_blk_config, num_queues, &num_vqs); - if (err) + /* We need at least one virtqueue */ + if (err || !num_vqs) num_vqs = 1; num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs);-- 2.25.1
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