[PATCH 3.18 25/26] USB: usbfs: Filter flags passed in from user space

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Oliver Neukum <oneukum@suse.com>

commit 446f666da9f019ce2ffd03800995487e79a91462 upstream.

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

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/core/devio.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1290,14 +1290,18 @@ static int proc_do_submiturb(struct usb_
 	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_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)