USB: usbtmc: fix probe error path

Make sure to initialise the return value to avoid having allocation
failures going unnoticed when allocating interrupt-endpoint resources.

This prevents use-after-free or worse when the device is later unbound.

Fixes: dbf3e7f654c0 ("Implement an ioctl to support the USMTMC-USB488 READ_STATUS_BYTE operation.")
Cc: stable <stable@vger.kernel.org>     # 4.6
Cc: Dave Penkler <dpenkler@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 5e3446db4513..8fb309a0ff6b 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -1476,8 +1476,10 @@ static int usbtmc_probe(struct usb_interface *intf,
         if (data->iin_ep_present) {
                 /* allocate int urb */
                 data->iin_urb = usb_alloc_urb(0, GFP_KERNEL);
-                if (!data->iin_urb)
+                if (!data->iin_urb) {
+                        retcode = -ENOMEM;
                         goto error_register;
+                }
 
                 /* Protect interrupt in endpoint data until iin_urb is freed */
                 kref_get(&data->kref);
@@ -1485,8 +1487,10 @@ static int usbtmc_probe(struct usb_interface *intf,
                 /* allocate buffer for interrupt in */
                 data->iin_buffer = kmalloc(data->iin_wMaxPacketSize,
                                         GFP_KERNEL);
-                if (!data->iin_buffer)
+                if (!data->iin_buffer) {
+                        retcode = -ENOMEM;
                         goto error_register;
+                }
 
                 /* fill interrupt urb */
                 usb_fill_int_urb(data->iin_urb, data->usb_dev,