[PATCH 5.16 020/121] vdpa: fix use-after-free on vp_vdpa_remove

[Greg Kroah-Hartman]

From: Zhang Min <zhang.min9@xxxxxxxxxx>

[ Upstream commit eb057b44dbe35ae14527830236a92f51de8f9184 ]

When vp_vdpa driver is unbind, vp_vdpa is freed in vdpa_unregister_device
and then vp_vdpa->mdev.pci_dev is dereferenced in vp_modern_remove,
triggering use-after-free.

Call Trace of unbinding driver free vp_vdpa :
do_syscall_64
  vfs_write
    kernfs_fop_write_iter
      device_release_driver_internal
        pci_device_remove
          vp_vdpa_remove
            vdpa_unregister_device
              kobject_release
                device_release
                  kfree

Call Trace of dereference vp_vdpa->mdev.pci_dev:
vp_modern_remove
  pci_release_selected_regions
    pci_release_region
      pci_resource_len
        pci_resource_end
          (dev)->resource[(bar)].end

Signed-off-by: Zhang Min <zhang.min9@xxxxxxxxxx>
Signed-off-by: Yi Wang <wang.yi59@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220301091059.46869-1-wang.yi59@xxxxxxxxxx
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Fixes: 64b9f64f80a6 ("vdpa: introduce virtio pci driver")
Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/vdpa/virtio_pci/vp_vdpa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index e3ff7875e123..fab161961160 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -525,8 +525,8 @@ static void vp_vdpa_remove(struct pci_dev *pdev)
 {
 	struct vp_vdpa *vp_vdpa = pci_get_drvdata(pdev);
 
-	vdpa_unregister_device(&vp_vdpa->vdpa);
 	vp_modern_remove(&vp_vdpa->mdev);
+	vdpa_unregister_device(&vp_vdpa->vdpa);
 }
 
 static struct pci_driver vp_vdpa_driver = {
-- 
2.34.1