[PATCHv2] USB: usbfs: Filter flags passed in from user space

[Oliver Neukum <oneukum@suse.com>]

USBDEVFS_URB_ISO_ASAP must be accepted only for ISO endpoints.
Improve sanity checking.

Reported-by: andreyknvl@google.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
CC: stable@vger.kernel.org
---
 drivers/usb/core/devio.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 705c573d0257..701ddada389a 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1442,14 +1442,18 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
 	int number_of_packets = 0;
 	unsigned int stream_id = 0;
 	void *buf;
-
-	if (uurb->flags & ~(USBDEVFS_URB_ISO_ASAP |
-				USBDEVFS_URB_SHORT_NOT_OK |
+	unsigned long mask =	USBDEVFS_URB_SHORT_NOT_OK |
 				USBDEVFS_URB_BULK_CONTINUATION |
 				USBDEVFS_URB_NO_FSBR |
-				USBDEVFS_URB_ZERO_PACKET |
-				USBDEVFS_URB_NO_INTERRUPT))
-		return -EINVAL;
+				USBDEVFS_URB_ZERO_PACKET | 
+				USBDEVFS_URB_NO_INTERRUPT;
+	/* USBDEVFS_URB_ISO_ASAP is a special case */
+	if (uurb->type == USBDEVFS_URB_TYPE_ISO)
+		mask |= USBDEVFS_URB_ISO_ASAP;
+
+	if (uurb->flags & ~mask)
+			return -EINVAL;
+
 	if ((unsigned int)uurb->buffer_length >= USBFS_XFER_MAX)
 		return -EINVAL;
 	if (uurb->buffer_length > 0 && !uurb->buffer)
-- 
2.13.6