[PATCH 3.2 014/140] USB: usbfs: Filter flags passed in from user space

Ben Hutchings
2018-02-28T15:20:21Z

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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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
@@ -1093,14 +1093,18 @@ static int proc_do_submiturb(struct dev_
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 &&