[PATCH 4.15 016/128] usbip: vudc: fix null pointer dereference on udc->lock

Greg Kroah-Hartman
2018-03-16T15:22:37Z

From: Colin Ian King <colin.king@canonical.com>

commit df3334c223a033f562645712e832ca4cbb326bbf upstream.

Currently the driver attempts to spin lock on udc->lock before a NULL
pointer check is performed on udc, hence there is a potential null
pointer dereference on udc->lock. Fix this by moving the null check
on udc before the lock occurs.

Fixes: ea6873a45a22 ("usbip: vudc: Add SysFS infrastructure for VUDC")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/usbip/vudc_sysfs.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/usb/usbip/vudc_sysfs.c
+++ b/drivers/usb/usbip/vudc_sysfs.c
@@ -105,10 +105,14 @@ static ssize_t store_sockfd(struct devic
if (rv != 0)
return -EINVAL;

+ if (!udc) {
+ dev_err(dev, "no device");
+ return -ENODEV;
+ }
spin_lock_irqsave(&udc->lock, flags);
/* Don't export what we don't have */
- if (!udc || !udc->driver || !udc->pullup) {
- dev_err(dev, "no device or gadget not bound");
+ if (!udc->driver || !udc->pullup) {
+ dev_err(dev, "gadget not bound");
ret = -ENODEV;
goto unlock;
}