From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933835AbdKAVVS (ORCPT ); Wed, 1 Nov 2017 17:21:18 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:35030 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933785AbdKAVVL (ORCPT ); Wed, 1 Nov 2017 17:21:11 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Willem de Bruijn , "David S . Miller" , Greg Kroah-Hartman , Willy Tarreau Subject: [PATCH 3.10 005/139] udp: consistently apply ufo or fragmentation Date: Wed, 1 Nov 2017 22:17:05 +0100 Message-Id: <1509571159-4405-6-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1509571159-4405-1-git-send-email-w@1wt.eu> References: <1509571159-4405-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Willem de Bruijn commit 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa upstream. 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. [gregkh - tweaks for 3.18 for ipv6, hopefully they are correct...] [wt: s/skb_is_gso/skb_has_frags for 3.10] 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 Signed-off-by: Willy Tarreau --- net/ipv4/ip_output.c | 7 +++++-- net/ipv4/udp.c | 2 +- net/ipv6/ip6_output.c | 7 ++++--- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 5f077ef..40faf48 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -846,10 +846,12 @@ static int __ip_append_data(struct sock *sk, csummode = CHECKSUM_PARTIAL; cork->length += length; - if (((length > mtu) || (skb && skb_has_frags(skb))) && + if ((skb && skb_has_frags(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_type == SOCK_DGRAM))) { err = ip_ufo_append_data(sk, queue, getfrag, from, length, hh_len, fragheaderlen, transhdrlen, maxfraglen, flags); @@ -1160,6 +1162,7 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, cork->length += size; 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)) { skb_shinfo(skb)->gso_size = mtu - fragheaderlen; diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 68174e4..882b23e 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -763,7 +763,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4) if (is_udplite) /* UDP-Lite */ csum = udplite_csum(skb); - else if (sk->sk_no_check == UDP_CSUM_NOXMIT) { /* UDP csum disabled */ + else if (sk->sk_no_check == UDP_CSUM_NOXMIT && !skb_has_frags(skb)) { /* UDP csum off */ skb->ip_summed = CHECKSUM_NONE; goto send; diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 17a88eb..3a65b9a 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1288,11 +1288,12 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, skb = skb_peek_tail(&sk->sk_write_queue); cork->length += length; - if (((length > mtu) || - (skb && skb_has_frags(skb))) && + if ((skb && skb_has_frags(skb)) || + (((length + fragheaderlen) > mtu) && + (skb_queue_len(&sk->sk_write_queue) <= 1) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && - (sk->sk_type == SOCK_DGRAM)) { + (sk->sk_type == SOCK_DGRAM))) { err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len, fragheaderlen, transhdrlen, mtu, flags, rt); -- 2.8.0.rc2.1.gbe9624a