From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57186 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727255AbeI0PuK (ORCPT ); Thu, 27 Sep 2018 11:50:10 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dave Taht , Eric Dumazet , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , "David S. Miller" Subject: [PATCH 4.4 11/28] gso_segment: Reset skb->mac_len after modifying network header Date: Thu, 27 Sep 2018 11:06:35 +0200 Message-Id: <20180927090638.162346987@linuxfoundation.org> In-Reply-To: <20180927090637.687829444@linuxfoundation.org> References: <20180927090637.687829444@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Toke H�iland-J�rgensen" [ Upstream commit c56cae23c6b167acc68043c683c4573b80cbcc2c ] When splitting a GSO segment that consists of encapsulated packets, the skb->mac_len of the segments can end up being set wrong, causing packet drops in particular when using act_mirred and ifb interfaces in combination with a qdisc that splits GSO packets. This happens because at the time skb_segment() is called, network_header will point to the inner header, throwing off the calculation in skb_reset_mac_len(). The network_header is subsequently adjust by the outer IP gso_segment handlers, but they don't set the mac_len. Fix this by adding skb_reset_mac_len() calls to both the IPv4 and IPv6 gso_segment handlers, after they modify the network_header. Many thanks to Eric Dumazet for his help in identifying the cause of the bug. Acked-by: Dave Taht Reviewed-by: Eric Dumazet Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/af_inet.c | 1 + net/ipv6/ip6_offload.c | 1 + 2 files changed, 2 insertions(+) --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1280,6 +1280,7 @@ static struct sk_buff *inet_gso_segment( if (encap) skb_reset_inner_headers(skb); skb->network_header = (u8 *)iph - skb->head; + skb_reset_mac_len(skb); } while ((skb = skb->next)); out: --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -118,6 +118,7 @@ static struct sk_buff *ipv6_gso_segment( ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h)); skb->network_header = (u8 *)ipv6h - skb->head; + skb_reset_mac_len(skb); if (udpfrag) { int err = ip6_find_1stfragopt(skb, &prevhdr);