Commit b6faaae1 authored Nov 22, 2010 by Marek Lindner Committed by Greg Kroah-Hartman Nov 29, 2010

Staging: batman-adv: ensure that eth_type_trans gets linear memory



eth_type_trans tries to pull data with the length of the ethernet header
from the skb. We only ensured that enough data for the first ethernet
header and the batman header is available in non-paged memory of the skb
and not for the ethernet after the batman header.

eth_type_trans would fail sometimes with drivers which don't ensure that
all there data is perfectly linearised.

The failure was noticed through a kernel bug Oops generated by the
skb_pull inside eth_type_trans.

Reported-by: Rafal Lesniak <lesniak@eresi-project.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 9ee89873

drivers/staging/batman-adv/soft-interface.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -194,14 +194,15 @@ void interface_rx(struct net_device *soft_iface,
		struct bat_priv *priv = netdev_priv(soft_iface);

		/* check if enough space is available for pulling, and pull */
		if (!pskb_may_pull(skb, hdr_size)) {
		kfree_skb(skb);
		return;
		}
		if (!pskb_may_pull(skb, hdr_size))
		goto dropped;

		skb_pull_rcsum(skb, hdr_size);
		/* skb_set_mac_header(skb, -sizeof(struct ethhdr));*/

		/* skb->dev & skb->pkt_type are set here */
		if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
		goto dropped;
		skb->protocol = eth_type_trans(skb, soft_iface);

		/* should not be neccesary anymore as we use skb_pull_rcsum()
		@@ -216,6 +217,11 @@ void interface_rx(struct net_device *soft_iface,
		soft_iface->last_rx = jiffies;

		netif_rx(skb);
		return;

		dropped:
		kfree_skb(skb);
		return;
		}

		#ifdef HAVE_NET_DEVICE_OPS