[PATCH 4.9 111/167] usb: usbip: add missing device lock on tweak configuration cmd

Greg Kroah-Hartman
2022-06-13T10:26:38Z

From: Niels Dossche <dossche.niels@gmail.com>

[ Upstream commit d088fabace2ca337b275d1d4b36db4fe7771e44f ]

The function documentation of usb_set_configuration says that its
callers should hold the device lock. This lock is held for all
callsites except tweak_set_configuration_cmd. The code path can be
executed for example when attaching a remote USB device.
The solution is to surround the call by the device lock.

This bug was found using my experimental own-developed static analysis
tool, which reported the missing lock on v5.17.2. I manually verified
this bug report by doing code review as well. I runtime checked that
the required lock is not held. I compiled and runtime tested this on
x86_64 with a USB mouse. After applying this patch, my analyser no
longer reports this potential bug.

Fixes: 2c8c98158946 ("staging: usbip: let client choose device configuration")
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Link: https://lore.kernel.org/r/20220412165055.257113-1-dossche.niels@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/usbip/stub_rx.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
index d47176f9c310..dd6228a51d0d 100644
--- a/drivers/usb/usbip/stub_rx.c
+++ b/drivers/usb/usbip/stub_rx.c
@@ -151,7 +151,9 @@ static int tweak_set_configuration_cmd(struct urb *urb)
req = (struct usb_ctrlrequest *) urb->setup_packet;
config = le16_to_cpu(req->wValue);

+ usb_lock_device(sdev->udev);
err = usb_set_configuration(sdev->udev, config);
+ usb_unlock_device(sdev->udev);
if (err && err != -ENODEV)
dev_err(&sdev->udev->dev, "can't set config #%d, error %d\n",
config, err);
--
2.35.1