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 Cc: stable@kernel.org --- This patch is the backport to v2.6.36 and was also submitted slightly different for 2.6.37 and 2.6.38.
drivers/staging/batman-adv/soft-interface.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/batman-adv/soft-interface.c b/drivers/staging/batman-adv/soft-interface.c index 2ea97de..876be5a 100644 --- a/drivers/staging/batman-adv/soft-interface.c +++ b/drivers/staging/batman-adv/soft-interface.c @@ -246,6 +246,10 @@ void interface_rx(struct sk_buff *skb, int hdr_size) skb_pull_rcsum(skb, hdr_size); /* skb_set_mac_header(skb, -sizeof(struct ethhdr));*/
+ if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) { + kfree_skb(skb); + return; + } skb->dev = dev; skb->protocol = eth_type_trans(skb, dev);