blob: b4379ea61bfdba22be1959378e17f70d19235ab6 [file] [log] [blame]
From 8835ba4a39cf53f705417b3b3a94eb067673f2c9 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Tue, 15 Mar 2016 10:14:04 +0100
Subject: USB: cdc-acm: more sanity checking
From: Oliver Neukum <oneukum@suse.com>
commit 8835ba4a39cf53f705417b3b3a94eb067673f2c9 upstream.
An attack has become available which pretends to be a quirky
device circumventing normal sanity checks and crashes the kernel
by an insufficient number of interfaces. This patch adds a check
to the code path for quirky devices.
Signed-off-by: Oliver Neukum <ONeukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/class/cdc-acm.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1114,6 +1114,9 @@ static int acm_probe(struct usb_interfac
if (quirks == NO_UNION_NORMAL) {
data_interface = usb_ifnum_to_if(usb_dev, 1);
control_interface = usb_ifnum_to_if(usb_dev, 0);
+ /* we would crash */
+ if (!data_interface || !control_interface)
+ return -ENODEV;
goto skip_normal_probe;
}