Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754032AbdHKWCE (ORCPT ); Fri, 11 Aug 2017 18:02:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33358 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753993AbdHKWB7 (ORCPT ); Fri, 11 Aug 2017 18:01:59 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Konovalov , Willem de Bruijn , "David S. Miller" Subject: [PATCH 4.9 14/16] udp: consistently apply ufo or fragmentation Date: Fri, 11 Aug 2017 15:01:44 -0700 Message-Id: <20170811220133.315298148@linuxfoundation.org> X-Mailer: git-send-email 2.14.0 In-Reply-To: <20170811220132.730037644@linuxfoundation.org> References: <20170811220132.730037644@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: 3200 Lines: 89 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn [ Upstream commit 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa ] When iteratively building a UDP datagram with MSG_MORE and that datagram exceeds MTU, consistently choose UFO or fragmentation. Once skb_is_gso, always apply ufo. Conversely, once a datagram is split across multiple skbs, do not consider ufo. Sendpage already maintains the first invariant, only add the second. IPv6 does not have a sendpage implementation to modify. A gso skb must have a partial checksum, do not follow sk_no_check_tx in udp_send_skb. Found by syzkaller. Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") Reported-by: Andrey Konovalov Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_output.c | 7 +++++-- net/ipv4/udp.c | 2 +- net/ipv6/ip6_output.c | 7 ++++--- 3 files changed, 10 insertions(+), 6 deletions(-) --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -936,10 +936,12 @@ static int __ip_append_data(struct sock csummode = CHECKSUM_PARTIAL; cork->length += length; - if (((length > mtu) || (skb && skb_is_gso(skb))) && + if ((skb && skb_is_gso(skb)) || + ((length > mtu) && + (skb_queue_len(queue) <= 1) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len && - (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx) { + (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx)) { err = ip_ufo_append_data(sk, queue, getfrag, from, length, hh_len, fragheaderlen, transhdrlen, maxfraglen, flags); @@ -1255,6 +1257,7 @@ ssize_t ip_append_page(struct sock *sk, return -EINVAL; if ((size + skb->len > mtu) && + (skb_queue_len(&sk->sk_write_queue) == 1) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO)) { if (skb->ip_summed != CHECKSUM_PARTIAL) --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -813,7 +813,7 @@ static int udp_send_skb(struct sk_buff * if (is_udplite) /* UDP-Lite */ csum = udplite_csum(skb); - else if (sk->sk_no_check_tx) { /* UDP csum disabled */ + else if (sk->sk_no_check_tx && !skb_is_gso(skb)) { /* UDP csum off */ skb->ip_summed = CHECKSUM_NONE; goto send; --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1372,11 +1372,12 @@ emsgsize: */ cork->length += length; - if ((((length + fragheaderlen) > mtu) || - (skb && skb_is_gso(skb))) && + if ((skb && skb_is_gso(skb)) || + (((length + fragheaderlen) > mtu) && + (skb_queue_len(queue) <= 1) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len && - (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk)) { + (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk))) { err = ip6_ufo_append_data(sk, queue, getfrag, from, length, hh_len, fragheaderlen, exthdrlen, transhdrlen, mtu, flags, fl6);