[PATCH 4.9 112/223] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()

Greg Kroah-Hartman
2019-08-02T09:45:04Z

From: Dexuan Cui <decui@microsoft.com>

commit 4df591b20b80cb77920953812d894db259d85bd7 upstream.

Fix a use-after-free in hv_eject_device_work().

Fixes: 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pci/host/pci-hyperv.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -1575,6 +1575,7 @@ static void hv_pci_devices_present(struc
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;
@@ -1585,6 +1586,7 @@ static void hv_eject_device_work(struct
} ctxt;

hpdev = container_of(work, struct hv_pci_dev, wrk);
+ hbus = hpdev->hbus;

if (hpdev->state != hv_pcichild_ejecting) {
put_pcichild(hpdev, hv_pcidev_ref_pnp);
@@ -1598,8 +1600,7 @@ static void hv_eject_device_work(struct
* because hbus->pci_bus may not exist yet.
*/
wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
- pdev = pci_get_domain_bus_and_slot(hpdev->hbus->sysdata.domain, 0,
- wslot);
+ pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
if (pdev) {
pci_lock_rescan_remove();
pci_stop_and_remove_bus_device(pdev);
@@ -1607,22 +1608,24 @@ static void hv_eject_device_work(struct
pci_unlock_rescan_remove();
}

- spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
+ spin_lock_irqsave(&hbus->device_list_lock, flags);
list_del(&hpdev->list_entry);
- spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
+ spin_unlock_irqrestore(&hbus->device_list_lock, flags);

memset(&ctxt, 0, sizeof(ctxt));
ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
- vmbus_sendpacket(hpdev->hbus->hdev->channel, ejct_pkt,
+ vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
VM_PKT_DATA_INBAND, 0);

put_pcichild(hpdev, hv_pcidev_ref_childlist);
put_pcichild(hpdev, hv_pcidev_ref_initial);
put_pcichild(hpdev, hv_pcidev_ref_pnp);
- put_hvpcibus(hpdev->hbus);
+
+ /* hpdev has been freed. Do not use it any more. */
+ put_hvpcibus(hbus);
}

/**