Commit 72103bd1 authored Nov 07, 2011 by Michael S. Tsirkin Committed by Rusty Russell Nov 14, 2011

virtio-pci: fix use after free



Commit 31a3ddda introduced
a use after free in virtio-pci. The main issue is
that the release method signals removal of the virtio device,
while remove signals removal of the pci device.

For example, on driver removal or hot-unplug,
virtio_pci_release_dev is called before virtio_pci_remove.
We then might get a crash as virtio_pci_remove tries to use the
device freed by virtio_pci_release_dev.

We allocate/free all resources together with the
pci device, so we can leave the release method empty.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org

parent 1ea6b8f4

drivers/virtio/virtio_pci.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -594,11 +594,11 @@ static struct virtio_config_ops virtio_pci_config_ops = {

		static void virtio_pci_release_dev(struct device *_d)
		{
		struct virtio_device *dev = container_of(_d, struct virtio_device,
		dev);
		struct virtio_pci_device *vp_dev = to_vp_device(dev);

		kfree(vp_dev);
		/*
		* No need for a release method as we allocate/free
		* all devices together with the pci devices.
		* Provide an empty one to avoid getting a warning from core.
		*/
		}

		/* the PCI probing function */
		@@ -686,6 +686,7 @@ static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
		pci_iounmap(pci_dev, vp_dev->ioaddr);
		pci_release_regions(pci_dev);
		pci_disable_device(pci_dev);
		kfree(vp_dev);
		}

		#ifdef CONFIG_PM