From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA432C282D8 for ; Fri, 1 Feb 2019 11:22:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A84221905 for ; Fri, 1 Feb 2019 11:22:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730123AbfBALWn (ORCPT ); Fri, 1 Feb 2019 06:22:43 -0500 Received: from packetmixer.de ([79.140.42.25]:44054 "EHLO mail.mail.packetmixer.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729077AbfBALWn (ORCPT ); Fri, 1 Feb 2019 06:22:43 -0500 Received: from kero.packetmixer.de (unknown [IPv6:2001:16b8:55d2:2000:d5de:4b5f:e820:eb9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mail.packetmixer.de (Postfix) with ESMTPSA id 0E74B6205A; Fri, 1 Feb 2019 12:14:16 +0100 (CET) From: Simon Wunderlich To: davem@davemloft.net Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH 2/3] batman-adv: Force mac header to start of data on xmit Date: Fri, 1 Feb 2019 12:14:11 +0100 Message-Id: <20190201111412.13807-3-sw@simonwunderlich.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190201111412.13807-1-sw@simonwunderlich.de> References: <20190201111412.13807-1-sw@simonwunderlich.de> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Sven Eckelmann 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@syzkaller.appspotmail.com Reported-by: syzbot+7d20bc3f1ddddc0f9079@syzkaller.appspotmail.com Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/soft-interface.c | 2 ++ 1 file changed, 2 insertions(+) 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)) { -- 2.11.0