From: Jason Wang <jasowang@redhat.com>
Date: Tue, 19 Oct 2021 15:01:43 +0800
Subject: virtio-blk: validate num_queues during probe
Git-commit: 6ae6ff6f6e7d2f304a12a53af8298e4f16ad633e
Patch-mainline: v5.16-rc1
References: jsc#PED-1559
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 failing the probe in this case.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20211019070152.8236-2-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Lee Duncan <lduncan@suse.com>
---
drivers/block/virtio_blk.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index a33fe0743672..dbcf2a7e4a00 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -571,6 +571,10 @@ static int init_vq(struct virtio_blk *vblk)
&num_vqs);
if (err)
num_vqs = 1;
+ if (!err && !num_vqs) {
+ dev_err(&vdev->dev, "MQ advertisted but zero queues reported\n");
+ return -EINVAL;
+ }
num_vqs = min_t(unsigned int,
min_not_zero(num_request_queues, nr_cpu_ids),