Commit 173d111b authored by Oliver Neukum's avatar Oliver Neukum Committed by Luis Henriques

USB: cdc-acm: more sanity checking

commit 8835ba4a 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: default avatarOliver Neukum <ONeukum@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Moritz Muehlenhoff <jmm@inutil.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 7ea6b63a
...@@ -1104,6 +1104,9 @@ static int acm_probe(struct usb_interface *intf, ...@@ -1104,6 +1104,9 @@ static int acm_probe(struct usb_interface *intf,
if (quirks == NO_UNION_NORMAL) { if (quirks == NO_UNION_NORMAL) {
data_interface = usb_ifnum_to_if(usb_dev, 1); data_interface = usb_ifnum_to_if(usb_dev, 1);
control_interface = usb_ifnum_to_if(usb_dev, 0); control_interface = usb_ifnum_to_if(usb_dev, 0);
/* we would crash */
if (!data_interface || !control_interface)
return -ENODEV;
goto skip_normal_probe; goto skip_normal_probe;
} }
......
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