[4.2.y-ckt stable] Patch "Input: powermate - fix oops with malicious USB descriptors" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    Input: powermate - fix oops with malicious USB descriptors

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 570d6777335a778ad00e18ee68f115beb9d728ca Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer at fedoraproject.org>
Date: Mon, 14 Mar 2016 09:33:40 -0700
Subject: Input: powermate - fix oops with malicious USB descriptors

commit 9c6ba456711687b794dcf285856fc14e2c76074f upstream.

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:
http://seclists.org/bugtraq/2016/Mar/85

Reported-by: Ralf Spenneberg <ralf at spenneberg.net>
Signed-off-by: Josh Boyer <jwboyer at fedoraproject.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>

Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 63b539d..84909a1 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;
--
2.7.4