Input: aiptek - fix crash on detecting device without endpoints

commit 8e20cf2bce122ce9262d6034ee5d5b76fbb92f96 upstream.

The aiptek driver crashes in aiptek_probe() when a specially crafted USB
device without endpoints is detected. This fix adds a check that the device
has proper configuration expected by the driver. Also an error return value
is changed to more matching one in one of the error paths.

Reported-by: Ralf Spenneberg <ralf@spenneberg.net>
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/input/tablet/aiptek.c b/drivers/input/tablet/aiptek.c
index 6d89fd1..5657018 100644 (file)
--- a/drivers/input/tablet/aiptek.c
+++ b/drivers/input/tablet/aiptek.c
@@ -1810,6 +1810,14 @@ aiptek_probe(struct usb_interface *intf, const struct usb_device_id *id)
        input_set_abs_params(inputdev, ABS_TILT_Y, AIPTEK_TILT_MIN, AIPTEK_TILT_MAX, 0, 0);
        input_set_abs_params(inputdev, ABS_WHEEL, AIPTEK_WHEEL_MIN, AIPTEK_WHEEL_MAX - 1, 0, 0);
 
+       /* Verify that a device really has an endpoint */
+       if (intf->altsetting[0].desc.bNumEndpoints < 1) {
+               dev_err(&intf->dev,
+                       "interface has %d endpoints, but must have minimum 1\n",
+                       intf->altsetting[0].desc.bNumEndpoints);
+               err = -EINVAL;
+               goto fail3;
+       }
        endpoint = &intf->altsetting[0].endpoint[0].desc;
 
        /* Go set up our URB, which is called when the tablet receives
@@ -1852,6 +1860,7 @@ aiptek_probe(struct usb_interface *intf, const struct usb_device_id *id)
        if (i == ARRAY_SIZE(speeds)) {
                dev_info(&intf->dev,
                         "Aiptek tried all speeds, no sane response\n");
+               err = -EINVAL;
                goto fail2;
        }