USB: digi_acceleport: do sanity checking for the number of ports

The driver can be crashed with devices that expose crafted descriptors
with too few endpoints.

See: http://seclists.org/bugtraq/2016/Mar/61

Signed-off-by: Oliver Neukum <ONeukum@suse.com>
[johan: fix OOB endpoint check and add error messages ]
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 010a42a92688954d7b65a82472d28fad346c80c3..16e8e37b3b36d521749ec48d17b2becfc4ae4f51 100644 (file)
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -1251,8 +1251,27 @@ static int digi_port_init(struct usb_serial_port *port, unsigned port_num)
 
 static int digi_startup(struct usb_serial *serial)
 {
+       struct device *dev = &serial->interface->dev;
        struct digi_serial *serial_priv;
        int ret;
+       int i;
+
+       /* check whether the device has the expected number of endpoints */
+       if (serial->num_port_pointers < serial->type->num_ports + 1) {
+               dev_err(dev, "OOB endpoints missing\n");
+               return -ENODEV;
+       }
+
+       for (i = 0; i < serial->type->num_ports + 1 ; i++) {
+               if (!serial->port[i]->read_urb) {
+                       dev_err(dev, "bulk-in endpoint missing\n");
+                       return -ENODEV;
+               }
+               if (!serial->port[i]->write_urb) {
+                       dev_err(dev, "bulk-out endpoint missing\n");
+                       return -ENODEV;
+               }
+       }
 
        serial_priv = kzalloc(sizeof(*serial_priv), GFP_KERNEL);
        if (!serial_priv)