From: Johan Hovold <johan@kernel.org>
Date: Thu, 9 Feb 2017 11:11:41 +0000 (+0100)
Subject: USB: serial: mos7840: fix another NULL-deref at open
X-Git-Tag: v3.10.106~126
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c8c6bd83bdb540466bef6a8ab89898e8e9ce2fd6;p=thirdparty%2Fkernel%2Fstable.git

USB: serial: mos7840: fix another NULL-deref at open

commit 5182c2cf2a9bfb7f066ef0bdd2bb6330b94dd74e upstream.

Fix another NULL-pointer dereference at open should a malicious device
lack an interrupt-in endpoint.

Note that the driver has a broken check for an interrupt-in endpoint
which means that an interrupt URB has never even been submitted.

Fixes: 3f5429746d91 ("USB: Moschip 7840 USB-Serial Driver")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 5041b6c5b2d26..3308c43d23131 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1041,6 +1041,7 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
 	 * (can't set it up in mos7840_startup as the structures *
 	 * were not set up at that time.)                        */
 	if (port0->open_ports == 1) {
+		/* FIXME: Buffer never NULL, so URB is not submitted. */
 		if (serial->port[0]->interrupt_in_buffer == NULL) {
 			/* set up interrupt urb */
 			usb_fill_int_urb(serial->port[0]->interrupt_in_urb,
@@ -2258,7 +2259,8 @@ static int mos7840_calc_num_ports(struct usb_serial *serial)
 static int mos7840_attach(struct usb_serial *serial)
 {
 	if (serial->num_bulk_in < serial->num_ports ||
-			serial->num_bulk_out < serial->num_ports) {
+			serial->num_bulk_out < serial->num_ports ||
+			serial->num_interrupt_in < 1) {
 		dev_err(&serial->interface->dev, "missing endpoints\n");
 		return -ENODEV;
 	}