6.1-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Anderson dianders@chromium.org
[ Upstream commit 44995e6f07028f798efd0c3c11a1efc78330f600 ]
It's possible that usb_choose_configuration() can get called when a USB device has no driver. In this case the recent commit a87b8e3be926 ("usb: core: Allow subclassed USB drivers to override usb_choose_configuration()") can cause a crash since it dereferenced the driver structure without checking for NULL. Let's add a check.
A USB device with no driver is an anomaly, so make usb_choose_configuration() return immediately if there is no driver.
This was seen in the real world when usbguard got ahold of a r8152 device at the wrong time. It can also be simulated via this on a computer with one r8152-based USB Ethernet adapter: cd /sys/bus/usb/drivers/r8152-cfgselector to_unbind="$(ls -d *-*)" real_dir="$(readlink -f "${to_unbind}")" echo "${to_unbind}" > unbind cd "${real_dir}" echo 0 > authorized echo 1 > authorized
Fixes: a87b8e3be926 ("usb: core: Allow subclassed USB drivers to override usb_choose_configuration()") Reviewed-by: Alan Stern stern@rowland.harvard.edu Signed-off-by: Douglas Anderson dianders@chromium.org Link: https://lore.kernel.org/r/20231211073237.v3.1.If27eb3bf7812f91ab83810f232292... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/core/generic.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index dcb897158228..b134bff5c3fe 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -59,7 +59,16 @@ int usb_choose_configuration(struct usb_device *udev) int num_configs; int insufficient_power = 0; struct usb_host_config *c, *best; - struct usb_device_driver *udriver = to_usb_device_driver(udev->dev.driver); + struct usb_device_driver *udriver; + + /* + * If a USB device (not an interface) doesn't have a driver then the + * kernel has no business trying to select or install a configuration + * for it. + */ + if (!udev->dev.driver) + return -1; + udriver = to_usb_device_driver(udev->dev.driver);
if (usb_device_is_owned(udev)) return 0;