From e6a87f147002fa16adcbafebbc458ff90a463474 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Tue, 15 Mar 2016 10:14:04 +0100
Subject: [PATCH] cdc-acm: more sanity checking
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>
CC: stable@vger.kernel.org
---
drivers/usb/class/cdc-acm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 26ca4f910cb0..a7732f80a912 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1113,6 +1113,9 @@ static int acm_probe(struct usb_interface *intf,
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;
}
--
2.5.0