[PATCH] USB: input: powermate: fix oops with malicious USB descriptors

From: Josh Boyer
Date: Mon Mar 14 2016 - 10:13:08 EST

The powermate driver expects at least one valid USB endpoint in its
probe function. If given malicious descriptors that specify 0 for
the number of endpoints, it will crash. Validate the number of
endpoints on the interface before using them.

The full report for this issue can be found here:

Reported-by: Ralf Spenneberg <ralf@xxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
drivers/input/misc/powermate.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/input/misc/powermate.c b/drivers/input/misc/powermate.c
index 63b539d3daba..84909a12ff36 100644
--- a/drivers/input/misc/powermate.c
+++ b/drivers/input/misc/powermate.c
@@ -307,6 +307,9 @@ static int powermate_probe(struct usb_interface *intf, const struct usb_device_i
int error = -ENOMEM;

interface = intf->cur_altsetting;
+ if (interface->desc.bNumEndpoints < 1)
+ return -EINVAL;
endpoint = &interface->endpoint[0].desc;
if (!usb_endpoint_is_int_in(endpoint))
return -EIO;