The following commit has been merged in the master branch: commit 9114daa825fc3f335f9bea3313ce667090187280 Author: Sven Eckelmann <sven(a)narfation.org&gt; Date: Mon Dec 31 22:31:01 2018 +0100 batman-adv: Force mac header to start of data on xmit The caller of ndo_start_xmit may not already have called skb_reset_mac_header. The returned value of skb_mac_header/eth_hdr therefore can be in the wrong position and even outside the current skbuff. This for example happens when the user binds to the device using a PF_PACKET-SOCK_RAW with enabled qdisc-bypass: int opt = 4; setsockopt(sock, SOL_PACKET, PACKET_QDISC_BYPASS, &opt, sizeof(opt)); Since eth_hdr is used all over the codebase, the batadv_interface_tx function must always take care of resetting it. Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Reported-by: syzbot+9d7405c7faa390e60b4e(a)syzkaller.appspotmail.com Reported-by: syzbot+7d20bc3f1ddddc0f9079(a)syzkaller.appspotmail.com Signed-off-by: Sven Eckelmann <sven(a)narfation.org&gt; Signed-off-by: Simon Wunderlich <sw(a)simonwunderlich.de&gt; diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 5db5a0a4c959..b85ca809e509 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -221,6 +221,8 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, netif_trans_update(soft_iface); vid = batadv_get_vid(skb, 0); + + skb_reset_mac_header(skb); ethhdr = eth_hdr(skb); switch (ntohs(ethhdr->h_proto)) { -- LinuxNextTracking