3.16.7-ckt27 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Oliver Neukum <oneukum@xxxxxxxx>
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@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Moritz Muehlenhoff <jmm@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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 332be4c5745c..54061a3bc5e9 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1104,6 +1104,9 @@ 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;
}
--
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