[BACKPORT 4.4.y 04/25] USB: iowarrior: fix oops with malicious USB descriptors

[Arnd Bergmann]

From: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>

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>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
(cherry picked from commit 4ec0ef3a82125efc36173062a50624550a900ae0)
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 drivers/usb/misc/iowarrior.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 5e43fd881a9c..381a92a0ebb6 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -787,6 +787,12 @@ static int iowarrior_probe(struct usb_interface *interface,
 	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;
-- 
2.20.0