From 983edac6e3cfc2926812713b43408826ab88af95 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Fri, 26 Feb 2016 17:56:13 +0100 Subject: [PATCH] batman-adv: Check skb size before using encapsulated ETH+VLAN header commit c78296665c3d81f040117432ab9e1cb125521b0c upstream. The encapsulated ethernet and VLAN header may be outside the received ethernet frame. Thus the skb buffer size has to be checked before it can be parsed to find out if it encapsulates another batman-adv packet. Fixes: 420193573f11 ("batman-adv: softif bridge loop avoidance") Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- net/batman-adv/soft-interface.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index f9cc95728989..a8f4627a426e 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -686,10 +686,16 @@ void interface_rx(struct net_device *soft_iface, skb_pull_rcsum(skb, hdr_size); skb_reset_mac_header(skb); + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) + goto dropped; + ethhdr = (struct ethhdr *)skb_mac_header(skb); switch (ntohs(ethhdr->h_proto)) { case ETH_P_8021Q: + if (!pskb_may_pull(skb, VLAN_ETH_HLEN)) + goto dropped; + vhdr = (struct vlan_ethhdr *)skb->data; vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK; @@ -726,8 +732,6 @@ void interface_rx(struct net_device *soft_iface, } /* 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 necessary anymore as we use skb_pull_rcsum() -- 2.39.5