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Commit 2a05ccfe authored by Badhri Jagan Sridharan's avatar Badhri Jagan Sridharan Committed by Dmitry Shmidt
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UPSTREAM: USB: cdc-acm: more sanity checking 



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.

BUG: 28242610

Signed-off-by: default avatarOliver Neukum <ONeukum@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarBadhri Jagan Sridharan <Badhri@google.com>
Change-Id: I9a5f7f3c704b65e866335054f470451fcfae9d1c
parent a54d8b3a

drivers/usb/class/cdc-acm.c

+3 −0
Original line number Diff line number Diff line
@@ -1107,6 +1107,9 @@ 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;

	}