Patch "USB: cdc-acm: more sanity checking" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

USB: cdc-acm: more sanity checking

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-cdc-acm-more-sanity-checking.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Oliver Neukum <[email protected]>
Date: Tue, 15 Mar 2016 10:14:04 +0100
Subject: USB: cdc-acm: more sanity checking

From: Oliver Neukum <[email protected]>

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.

---
 drivers/usb/class/cdc-acm.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -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;
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/usb-cdc-acm-more-sanity-checking.patch queue-4.4/usb-mct_u232-add-sanity-checking-in-probe.patch queue-4.4/usb-digi_acceleport-do-sanity-checking-for-the-number-of-ports.patch queue-4.4/usb-cypress_m8-add-endpoint-sanity-check.patch queue-4.4/usb-retry-reset-if-a-device-times-out.patch queue-4.4/usb-hub-fix-a-typo-in-hub_port_init-leading-to-wrong-logic.patch queue-4.4/usb-usb_driver_claim_interface-add-sanity-checking.patch