Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934896AbcLIQWV (ORCPT ); Fri, 9 Dec 2016 11:22:21 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56128 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934030AbcLIQWS (ORCPT ); Fri, 9 Dec 2016 11:22:18 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sabrina Dubroca , "John W. Linville" , "David S. Miller" Subject: [PATCH 4.8 28/45] geneve: avoid use-after-free of skb->data Date: Fri, 9 Dec 2016 17:20:57 +0100 Message-Id: <20161209161756.129300896@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161209161754.912203877@linuxfoundation.org> References: <20161209161754.912203877@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3174 Lines: 96 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sabrina Dubroca [ Upstream commit 5b01014759991887b1e450c9def01e58c02ab81b ] geneve{,6}_build_skb can end up doing a pskb_expand_head(), which makes the ip_hdr(skb) reference we stashed earlier stale. Since it's only needed as an argument to ip_tunnel_ecn_encap(), move this directly in the function call. Fixes: 08399efc6319 ("geneve: ensure ECN info is handled properly in all tx/rx paths") Signed-off-by: Sabrina Dubroca Reviewed-by: John W. Linville Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/geneve.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -844,7 +844,6 @@ static netdev_tx_t geneve_xmit_skb(struc struct geneve_dev *geneve = netdev_priv(dev); struct geneve_sock *gs4 = geneve->sock4; struct rtable *rt = NULL; - const struct iphdr *iip; /* interior IP header */ int err = -EINVAL; struct flowi4 fl4; __u8 tos, ttl; @@ -871,8 +870,6 @@ static netdev_tx_t geneve_xmit_skb(struc sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true); skb_reset_mac_header(skb); - iip = ip_hdr(skb); - if (info) { const struct ip_tunnel_key *key = &info->key; u8 *opts = NULL; @@ -892,7 +889,7 @@ static netdev_tx_t geneve_xmit_skb(struc if (unlikely(err)) goto tx_error; - tos = ip_tunnel_ecn_encap(key->tos, iip, skb); + tos = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb); ttl = key->ttl; df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0; } else { @@ -901,7 +898,7 @@ static netdev_tx_t geneve_xmit_skb(struc if (unlikely(err)) goto tx_error; - tos = ip_tunnel_ecn_encap(fl4.flowi4_tos, iip, skb); + tos = ip_tunnel_ecn_encap(fl4.flowi4_tos, ip_hdr(skb), skb); ttl = geneve->ttl; if (!ttl && IN_MULTICAST(ntohl(fl4.daddr))) ttl = 1; @@ -934,7 +931,6 @@ static netdev_tx_t geneve6_xmit_skb(stru struct geneve_dev *geneve = netdev_priv(dev); struct geneve_sock *gs6 = geneve->sock6; struct dst_entry *dst = NULL; - const struct iphdr *iip; /* interior IP header */ int err = -EINVAL; struct flowi6 fl6; __u8 prio, ttl; @@ -959,8 +955,6 @@ static netdev_tx_t geneve6_xmit_skb(stru sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true); skb_reset_mac_header(skb); - iip = ip_hdr(skb); - if (info) { const struct ip_tunnel_key *key = &info->key; u8 *opts = NULL; @@ -981,7 +975,7 @@ static netdev_tx_t geneve6_xmit_skb(stru if (unlikely(err)) goto tx_error; - prio = ip_tunnel_ecn_encap(key->tos, iip, skb); + prio = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb); ttl = key->ttl; label = info->key.label; } else { @@ -991,7 +985,7 @@ static netdev_tx_t geneve6_xmit_skb(stru goto tx_error; prio = ip_tunnel_ecn_encap(ip6_tclass(fl6.flowlabel), - iip, skb); + ip_hdr(skb), skb); ttl = geneve->ttl; if (!ttl && ipv6_addr_is_multicast(&fl6.daddr)) ttl = 1;