[3.19.y-ckt stable] Patch "batman-adv: Fix potentially broken skb network header access" has been added to staging queue

[Kamal Mostafa]

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

    batman-adv: Fix potentially broken skb network header access

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt8.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From 9b4f0e192660536c5c837f37910dc35d07777c0c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20L=C3=BCssing?= <linus.luessing at c0d3.blue>
Date: Tue, 30 Jun 2015 23:45:26 +0200
Subject: batman-adv: Fix potentially broken skb network header access
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 53cf037bf846417fd92dc92ddf97267f69b110f4 upstream.

The two commits noted below added calls to ip_hdr() and ipv6_hdr(). They
need a correctly set skb network header.

Unfortunately we cannot rely on the device drivers to set it for us.
Therefore setting it in the beginning of the according ndo_start_xmit
handler.

Fixes: 1d8ab8d3c176 ("batman-adv: Modified forwarding behaviour for multicast packets")
Fixes: ab49886e3da7 ("batman-adv: Add IPv4 link-local/IPv6-ll-all-nodes multicast support")
Signed-off-by: Linus Lüssing <linus.luessing at c0d3.blue>
Signed-off-by: Marek Lindner <mareklindner at neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio at meshcoding.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/batman-adv/soft-interface.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 8e66b01..43fdae0 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -173,6 +173,7 @@ static int batadv_interface_tx(struct sk_buff *skb,
 	int gw_mode;
 	enum batadv_forw_mode forw_mode;
 	struct batadv_orig_node *mcast_single_orig = NULL;
+	int network_offset = ETH_HLEN;

 	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		goto dropped;
@@ -185,14 +186,18 @@ static int batadv_interface_tx(struct sk_buff *skb,
 	case ETH_P_8021Q:
 		vhdr = vlan_eth_hdr(skb);

-		if (vhdr->h_vlan_encapsulated_proto != ethertype)
+		if (vhdr->h_vlan_encapsulated_proto != ethertype) {
+			network_offset += VLAN_HLEN;
 			break;
+		}

 		/* fall through */
 	case ETH_P_BATMAN:
 		goto dropped;
 	}

+	skb_set_network_header(skb, network_offset);
+
 	if (batadv_bla_tx(bat_priv, skb, vid))
 		goto dropped;

--
1.9.1