Thread (55 messages) flat view 55 messages, 7 authors, 2021-10-12

Re: [PATCH 1/9] virtio-blk: validate num_queues during probe

From: Jason Wang <hidden>
Date: 2021-09-14 02:29:44
Also in: lkml

在 2021/9/13 下午3:48, Stefano Garzarella 写道:
On Mon, Sep 13, 2021 at 01:53:45PM +0800, Jason Wang wrote:
quoted
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>
Signed-off-by: Jason Wang <redacted>
---
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 e574fbf5e6df..f130d12df4b9 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -498,7 +498,8 @@ 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 on virtqueue */
s/on/one/

The rest LGTM.

Stefano

Will fix in next version.

Thanks

quoted
+    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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