From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:54706 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726944AbeI0PYU (ORCPT ); Thu, 27 Sep 2018 11:24:20 -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 4.18 01/88] gso_segment: Reset skb->mac_len after modifying network header Date: Thu, 27 Sep 2018 11:02:42 +0200 Message-Id: <20180927090300.788614977@linuxfoundation.org> In-Reply-To: <20180927090300.631426620@linuxfoundation.org> References: <20180927090300.631426620@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: 4.18-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 @@ -1377,6 +1377,7 @@ struct sk_buff *inet_gso_segment(struct 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 @@ -115,6 +115,7 @@ static struct sk_buff *ipv6_gso_segment( payload_len = skb->len - nhoff - sizeof(*ipv6h); ipv6h->payload_len = htons(payload_len); skb->network_header = (u8 *)ipv6h - skb->head; + skb_reset_mac_len(skb); if (udpfrag) { int err = ip6_find_1stfragopt(skb, &prevhdr);