[PATCH 3.16 021/254] USB: usbfs: Filter flags passed in from user space

From: Ben Hutchings
Date: Wed Feb 28 2018 - 10:36:29 EST


3.16.55-rc1 review patch. If anyone has any objections, please let me know.

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

From: Oliver Neukum <oneukum@xxxxxxxx>

commit 446f666da9f019ce2ffd03800995487e79a91462 upstream.

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

Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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
@@ -1295,14 +1295,18 @@ 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 (uurb->buffer_length > 0 && !uurb->buffer)
return -EINVAL;
if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&