| Message ID | 20230316175457.1595921-1-zyytlz.wz@163.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v6] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition | expand |
On Fri, Mar 17, 2023 at 01:54:57AM +0800, Zheng Wang wrote: > In renesas_usb3_probe, role_work is bound with renesas_usb3_role_work. > renesas_usb3_start will be called to start the work. > > If we remove the driver which will call usbhs_remove, there may be > an unfinished work. The possible sequence is as follows: > > Fix it by canceling the work before cleanup in the renesas_usb3_remove. > > Note that removing a driver is a root-only operation, and should never > happen. > > CPU0 CPU1 > > | renesas_usb3_role_work > renesas_usb3_remove | > usb_role_switch_unregister| > device_unregister | > kfree(sw) | > free usb3->role_sw | > | usb_role_switch_set_role > | //use usb3->role_sw Please use spaces for this, as something went wrong and it does not line up :(
diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c index bee6bceafc4f..a301af66bd91 100644 --- a/drivers/usb/gadget/udc/renesas_usb3.c +++ b/drivers/usb/gadget/udc/renesas_usb3.c @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev) debugfs_remove_recursive(usb3->dentry); device_remove_file(&pdev->dev, &dev_attr_role); + cancel_work_sync(&usb3->role_work); usb_role_switch_unregister(usb3->role_sw); usb_del_gadget_udc(&usb3->gadget);
In renesas_usb3_probe, role_work is bound with renesas_usb3_role_work. renesas_usb3_start will be called to start the work. If we remove the driver which will call usbhs_remove, there may be an unfinished work. The possible sequence is as follows: Fix it by canceling the work before cleanup in the renesas_usb3_remove. Note that removing a driver is a root-only operation, and should never happen. CPU0 CPU1 | renesas_usb3_role_work renesas_usb3_remove | usb_role_switch_unregister| device_unregister | kfree(sw) | free usb3->role_sw | | usb_role_switch_set_role | //use usb3->role_sw Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch") Signed-off-by: Zheng Wang <zyytlz.wz@163.com> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> --- v6: - beautify the format and add note suggested by Greg KH v5: - fix typo v4: - add Reviewed-by label and resubmit v4 suggested by Greg KH v3: - modify the commit message to make it clearer suggested by Yoshihiro Shimoda v2: - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda --- drivers/usb/gadget/udc/renesas_usb3.c | 1 + 1 file changed, 1 insertion(+)