[PATCH 05/11][CVE-2016-2188] USB: iowarrior: fix oops with malicious USB descriptors

[Luis Henriques]

From: Josh Boyer <jwboyer at fedoraproject.org>

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 at spenneberg.net>
Signed-off-by: Josh Boyer <jwboyer at fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
CVE-2016-2188
BugLink: https://bugs.launchpad.net/bugs/1561414
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 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 81457904d6ba..2fce7197fa7b 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -792,6 +792,12 @@ 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;