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>
CC: stable@xxxxxxxxxxxxxxx
---
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 1d2c99a..83fd30b 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1179,6 +1179,9 @@ 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;
}
--
2.1.4
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