[PATCH V3 01/10] virtio-blk: validate num_queues during probe

From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, jasowang@redhat.com
Cc: david.kaplan@amd.com, konrad.wilk@oracle.com,
	f.hetzelt@tu-berlin.de, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH V3 01/10] virtio-blk: validate num_queues during probe
Date: Tue, 19 Oct 2021 15:01:43 +0800	[thread overview]
Message-ID: <20211019070152.8236-2-jasowang@redhat.com> (raw)
In-Reply-To: <20211019070152.8236-1-jasowang@redhat.com>

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>
---
 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 9b3bd083b411..10bc0879e618 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -497,6 +497,10 @@ 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, nr_cpu_ids, num_vqs);
 
-- 
2.25.1

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