From: Marek Lindner lindner_marek@yahoo.de
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 --- The same patch was also submitted for 2.6.38 and it is also possible to merge that patch in 2.6.37 and then merge 2.6.37 in 2.6.28
drivers/staging/batman-adv/soft-interface.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/batman-adv/soft-interface.c b/drivers/staging/batman-adv/soft-interface.c index 3904db9..0e99618 100644 --- a/drivers/staging/batman-adv/soft-interface.c +++ b/drivers/staging/batman-adv/soft-interface.c @@ -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