From: Michael S. Tsirkin Date: Mon, 7 Nov 2011 16:37:05 +0000 (+0200) Subject: virtio-pci: fix use after free X-Git-Tag: firefly_0821_release~3680^2~4115^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=72103bd1285211440621f2c46f4fce377584de54;p=firefly-linux-kernel-4.4.55.git virtio-pci: fix use after free Commit 31a3ddda166cda86d2b5111e09ba4bda5239fae6 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 Acked-by: Amit Shah Signed-off-by: Rusty Russell Cc: stable@kernel.org --- diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 79a31e5b4b68..3d1bf41e8892 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -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