RE: [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()

From: Dexuan Cui
Date: Fri Jun 21 2019 - 19:32:04 EST



> From: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> > @@ -1880,6 +1880,7 @@ static void hv_pci_devices_present(struct
> hv_pcibus_device
> > *hbus,
> > static void hv_eject_device_work(struct work_struct *work)
> > {
> > struct pci_eject_response *ejct_pkt;
> > + struct hv_pcibus_device *hbus;
> > struct hv_pci_dev *hpdev;
> > struct pci_dev *pdev;
> > unsigned long flags;
> > @@ -1890,6 +1891,7 @@ static void hv_eject_device_work(struct
> work_struct *work)
> > } ctxt;
> >
> > hpdev = container_of(work, struct hv_pci_dev, wrk);
> > + hbus = hpdev->hbus;
>
> In the lines of code following this new assignment, there are four uses of
> hpdev->hbus besides the one at the bottom of the function that causes the
> use-after-free error. With 'hbus' now available as a local variable, it looks
> rather strange to have those other places still using hpdev->hbus. I'm
> thinking
> they should be shortened to just 'hbus' for consistency, even though such
> changes aren't directly related to fixing the bug.
>
> Michael

Ok, let me post a v2 for this.

Thanks,
Dexuan