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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 C7A75C10F12 for ; Mon, 15 Apr 2019 19:11:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 96FE4218DA for ; Mon, 15 Apr 2019 19:11:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555355476; bh=GHfEZerv/dZ+K0CfBlj9WxxoL5dE0wTtUvqClbPDPOA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Wdu2K9oH1pHvk4F/84viEETkNbTr+MSKTdeqeam3WGeRsiI0N3TN4Rr553+83PjlX BSnocI/ITlz2Epjm18CQCTJeTiVFa/qt/NxPefD6HlJWCdxGQY3/QWN72iQ3pZxqoE 27bQw+XQT5rxK1dSk/XNFUi51qHX2sCE5XaDLzOM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731190AbfDOTLP (ORCPT ); Mon, 15 Apr 2019 15:11:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:47942 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731158AbfDOTLI (ORCPT ); Mon, 15 Apr 2019 15:11:08 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 B7A85218A1; Mon, 15 Apr 2019 19:11:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555355467; bh=GHfEZerv/dZ+K0CfBlj9WxxoL5dE0wTtUvqClbPDPOA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ELlwPXkUXh16N1jMokVWsDc8wPmyIyGEtbjopYD6NFsW95XTOi1ElyUWUMVY1bsyL CQj+TEyjDL/3WSqijFIP+KqH55MX8ROEEllbLZrp/vmCzn9lehKziYGDV1BFvGJHMP IejMWFgPTEmAq8OR/KjSobJRa3g+lXgaMTy7FM+k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lorenzo Bianconi , "David S. Miller" , Sasha Levin Subject: [PATCH 5.0 032/117] net: ip_gre: fix possible use-after-free in erspan_rcv Date: Mon, 15 Apr 2019 21:00:02 +0200 Message-Id: <20190415183746.593973081@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190415183744.887851196@linuxfoundation.org> References: <20190415183744.887851196@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 492b67e28ee5f2a2522fb72e3d3bcb990e461514 ] erspan tunnels run __iptunnel_pull_header on received skbs to remove gre and erspan headers. This can determine a possible use-after-free accessing pkt_md pointer in erspan_rcv since the packet will be 'uncloned' running pskb_expand_head if it is a cloned gso skb (e.g if the packet has been sent though a veth device). Fix it resetting pkt_md pointer after __iptunnel_pull_header Fixes: 1d7e2ed22f8d ("net: erspan: refactor existing erspan code") Signed-off-by: Lorenzo Bianconi Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/ip_gre.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 6ae89f2b541b..2d5734079e6b 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -259,7 +259,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, struct net *net = dev_net(skb->dev); struct metadata_dst *tun_dst = NULL; struct erspan_base_hdr *ershdr; - struct erspan_metadata *pkt_md; struct ip_tunnel_net *itn; struct ip_tunnel *tunnel; const struct iphdr *iph; @@ -282,9 +281,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, if (unlikely(!pskb_may_pull(skb, len))) return PACKET_REJECT; - ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len); - pkt_md = (struct erspan_metadata *)(ershdr + 1); - if (__iptunnel_pull_header(skb, len, htons(ETH_P_TEB), @@ -292,8 +288,9 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, goto drop; if (tunnel->collect_md) { + struct erspan_metadata *pkt_md, *md; struct ip_tunnel_info *info; - struct erspan_metadata *md; + unsigned char *gh; __be64 tun_id; __be16 flags; @@ -306,6 +303,14 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, if (!tun_dst) return PACKET_REJECT; + /* skb can be uncloned in __iptunnel_pull_header, so + * old pkt_md is no longer valid and we need to reset + * it + */ + gh = skb_network_header(skb) + + skb_network_header_len(skb); + pkt_md = (struct erspan_metadata *)(gh + gre_hdr_len + + sizeof(*ershdr)); md = ip_tunnel_info_opts(&tun_dst->u.tun_info); md->version = ver; md2 = &md->u.md2; -- 2.19.1