Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756035AbcCAX4p (ORCPT <rfc822;w@1wt.eu>);
	Tue, 1 Mar 2016 18:56:45 -0500
Received: from mail333.us4.mandrillapp.com ([205.201.137.77]:56744 "EHLO
	mail333.us4.mandrillapp.com" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1755981AbcCAX4h (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 1 Mar 2016 18:56:37 -0500
DomainKey-Signature: a=rsa-sha1; c=nofws; q=dns; s=mandrill; d=linuxfoundation.org;
 b=TQceiglM+XJdzzIJ+TmDFnSDJ2U0WI4zi0NdyIvorPlqjrUN8x4xfdLutOz4DFiVcqB1QY/zq1rf
   lDMMyDNMP+WoT4ym2sMxL8BYZxH1IqAP4WSZZaDp3mH7DZAs30+/hgeY4edfxItZ3lu3fgsxunj0
   0p27cQy+725v0faVock=;
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH 4.4 150/342] Bluetooth: 6lowpan: Fix kernel NULL pointer dereferences
X-Mailer: git-send-email 2.7.2
To: <linux-kernel@vger.kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, <stable@vger.kernel.org>,
        Glenn Ruben Bakke <glenn.ruben.bakke@nordicsemi.no>,
        Lukasz Duda <lukasz.duda@nordicsemi.no>,
        Jukka Rissanen <jukka.rissanen@linux.intel.com>,
        Johan Hedberg <johan.hedberg@intel.com>
Message-Id: <20160301234532.817504202@linuxfoundation.org>
In-Reply-To: <20160301234527.990448862@linuxfoundation.org>
References: <20160301234527.990448862@linuxfoundation.org>
X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com
X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=30481620.c767beb85ede4f7ba3dcda822164e0de
X-Mandrill-User: md_30481620
Date: Tue, 01 Mar 2016 23:54:33 +0000
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2758
Lines: 85

4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Glenn Ruben Bakke <glenn.ruben.bakke@nordicsemi.no>

commit 4c58f3282e3de43d34f8955f8eca676294380bf9 upstream.

The fixes provided in this patch assigns a valid net_device structure to
skb before dispatching it for further processing.

Scenario #1:
============

Bluetooth 6lowpan receives an uncompressed IPv6 header, and dispatches it
to netif. The following error occurs:

Null pointer dereference error #1 crash log:

[  845.854013] BUG: unable to handle kernel NULL pointer dereference at
               0000000000000048
[  845.855785] IP: [<ffffffff816e3d36>] enqueue_to_backlog+0x56/0x240
...
[  845.909459] Call Trace:
[  845.911678]  [<ffffffff816e3f64>] netif_rx_internal+0x44/0xf0

The first modification fixes the NULL pointer dereference error by
assigning dev to the local_skb in order to set a valid net_device before
processing the skb by netif_rx_ni().

Scenario #2:
============

Bluetooth 6lowpan receives an UDP compressed message which needs further
decompression by nhc_udp. The following error occurs:

Null pointer dereference error #2 crash log:

[   63.295149] BUG: unable to handle kernel NULL pointer dereference at
               0000000000000840
[   63.295931] IP: [<ffffffffc0559540>] udp_uncompress+0x320/0x626
               [nhc_udp]

The second modification fixes the NULL pointer dereference error by
assigning dev to the local_skb in the case of a udp compressed packet.
The 6lowpan udp_uncompress function expects that the net_device is set in
the skb when checking lltype.

Signed-off-by: Glenn Ruben Bakke <glenn.ruben.bakke@nordicsemi.no>
Signed-off-by: Lukasz Duda <lukasz.duda@nordicsemi.no>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/bluetooth/6lowpan.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -317,6 +317,7 @@ static int recv_pkt(struct sk_buff *skb,
 
 		local_skb->protocol = htons(ETH_P_IPV6);
 		local_skb->pkt_type = PACKET_HOST;
+		local_skb->dev = dev;
 
 		skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
 
@@ -335,6 +336,8 @@ static int recv_pkt(struct sk_buff *skb,
 		if (!local_skb)
 			goto drop;
 
+		local_skb->dev = dev;
+
 		ret = iphc_decompress(local_skb, dev, chan);
 		if (ret < 0) {
 			kfree_skb(local_skb);
@@ -343,7 +346,6 @@ static int recv_pkt(struct sk_buff *skb,
 
 		local_skb->protocol = htons(ETH_P_IPV6);
 		local_skb->pkt_type = PACKET_HOST;
-		local_skb->dev = dev;
 
 		if (give_skb_to_upper(local_skb, dev)
 				!= NET_RX_SUCCESS) {