[PATCH 3.2 044/115] USB: iowarrior: fix oops with malicious USB descriptors

[Ben Hutchings]

3.2.80-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>

commit 4ec0ef3a82125efc36173062a50624550a900ae0 upstream.

The iowarrior driver expects at least one valid endpoint.  If given
malicious descriptors that specify 0 for the number of endpoints,
it will crash in the probe function.  Ensure there is at least
one endpoint on the interface before using it.

The full report of this issue can be found here:
http://seclists.org/bugtraq/2016/Mar/87

Reported-by: Ralf Spenneberg <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/misc/iowarrior.c | 6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -792,6 +792,12 @@ static int iowarrior_probe(struct usb_in
 	iface_desc = interface->cur_altsetting;
 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
 
+	if (iface_desc->desc.bNumEndpoints < 1) {
+		dev_err(&interface->dev, "Invalid number of endpoints\n");
+		retval = -EINVAL;
+		goto error;
+	}
+
 	/* set up the endpoint information */
 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 		endpoint = &iface_desc->endpoint[i].desc;