[PATCH 3.2 065/115] USB: cypress_m8: add endpoint sanity check

From: Ben Hutchings
Date: Tue Apr 26 2016 - 19:29:40 EST


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

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

From: Oliver Neukum <oneukum@xxxxxxxx>

commit c55aee1bf0e6b6feec8b2927b43f7a09a6d5f754 upstream.

An attack using missing endpoints exists.

CVE-2016-3137

Signed-off-by: Oliver Neukum <ONeukum@xxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/serial/cypress_m8.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -489,6 +489,11 @@ static int generic_startup(struct usb_se

dbg("%s - port %d", __func__, port->number);

+ if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
+ dev_err(&port->dev, "required endpoint is missing\n");
+ return -ENODEV;
+ }
+
priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
if (!priv)
return -ENOMEM;
@@ -658,12 +663,6 @@ static int cypress_open(struct tty_struc
cypress_set_termios(tty, port, &priv->tmp_termios);

/* setup the port and start reading from the device */
- if (!port->interrupt_in_urb) {
- dev_err(&port->dev, "%s - interrupt_in_urb is empty!\n",
- __func__);
- return -1;
- }
-
usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
port->interrupt_in_urb->transfer_buffer,