USB: usbfs: Filter flags passed in from user space

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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index caf7100..a33e3cb 100644 (file)
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1093,14 +1093,18 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
        unsigned int u, totlen, isofrmlen;
        int ret, ifnum = -1;
        int is_in;
-
-       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 (uurb->buffer_length > 0 && !uurb->buffer)
                return -EINVAL;
        if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&