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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 580BDC433E7 for ; Mon, 12 Oct 2020 13:57:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE78F2076E for ; Mon, 12 Oct 2020 13:57:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602511040; bh=beGJu3rWvTpblMJs/GmKYmVmzuSd2vlgK2kh3X3A9rc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=P5ehmclzjPOTUyJRVu6LvZ0k4XLl7w8Txafsc7NEBLyrdQG7eAoi3+kK8XjyCCNQQ P8SSgR/br+Tusj5TZQqsW8Lj68DDxwr24rgETnUHC5QzhlzRIxNQ2u0606gunTptc1 3uup2UXGyrElOnvk6PWBMUWpj3Jbg9ClkmxYRa4U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390603AbgJLN5T (ORCPT ); Mon, 12 Oct 2020 09:57:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:46218 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389365AbgJLNnk (ORCPT ); Mon, 12 Oct 2020 09:43:40 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 31F2A22251; Mon, 12 Oct 2020 13:43:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602510210; bh=beGJu3rWvTpblMJs/GmKYmVmzuSd2vlgK2kh3X3A9rc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0W13JXoGHMjhk38Hkz31/TiDWwZyMVkUFFj9tWxJmQmXDPnGamwj4pYZ1uTfTbfz6 18PuqRVCBq/UIRs3q2rRJ0o4ody83riHkNo0tcxT1oA7PaKPVnD/j4vgeFBaftwsYu 7S/Op2nZLIHwt47oZXqPX2e1wThLLmY2ZLQn1CPM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guillaume Nault , Davide Caratti , "David S. Miller" Subject: [PATCH 5.4 79/85] net/core: check length before updating Ethertype in skb_mpls_{push,pop} Date: Mon, 12 Oct 2020 15:27:42 +0200 Message-Id: <20201012132636.643978471@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012132632.846779148@linuxfoundation.org> References: <20201012132632.846779148@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guillaume Nault commit 4296adc3e32f5d544a95061160fe7e127be1b9ff upstream. Openvswitch allows to drop a packet's Ethernet header, therefore skb_mpls_push() and skb_mpls_pop() might be called with ethernet=true and mac_len=0. In that case the pointer passed to skb_mod_eth_type() doesn't point to an Ethernet header and the new Ethertype is written at unexpected locations. Fix this by verifying that mac_len is big enough to contain an Ethernet header. Fixes: fa4e0f8855fc ("net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions") Signed-off-by: Guillaume Nault Acked-by: Davide Caratti Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5515,7 +5515,7 @@ int skb_mpls_push(struct sk_buff *skb, _ lse->label_stack_entry = mpls_lse; skb_postpush_rcsum(skb, lse, MPLS_HLEN); - if (ethernet) + if (ethernet && mac_len >= ETH_HLEN) skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto); skb->protocol = mpls_proto; @@ -5555,7 +5555,7 @@ int skb_mpls_pop(struct sk_buff *skb, __ skb_reset_mac_header(skb); skb_set_network_header(skb, mac_len); - if (ethernet) { + if (ethernet && mac_len >= ETH_HLEN) { struct ethhdr *hdr; /* use mpls_hdr() to get ethertype to account for VLANs. */