[PATCH 4.5 057/238] USB: cdc-acm: more sanity checking

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.5 057/238] USB: cdc-acm: more sanity checking
Date	2016-04-10 20:50 +0200
Message-ID	<rmsAO-Sh-41@gated-at.bofh.it> (permalink)
References	<rmsr7-Nr-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.5-stable review patch.  If anyone has any objections, please let me know.

------------------

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;
 	}

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[PATCH 4.5 057/238] USB: cdc-acm: more sanity checking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 20:50 +0200

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