Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932092AbcD0A0S (ORCPT ); Tue, 26 Apr 2016 20:26:18 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:39925 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753788AbcDZXNq (ORCPT ); Tue, 26 Apr 2016 19:13:46 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David S. Miller" , "Bill Sommerfeld" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 200/217] udp6: fix UDP/IPv6 encap resubmit path In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1401 Lines: 42 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Bill Sommerfeld [ Upstream commit 59dca1d8a6725a121dae6c452de0b2611d5865dc ] IPv4 interprets a negative return value from a protocol handler as a request to redispatch to a new protocol. In contrast, IPv6 interprets a negative value as an error, and interprets a positive value as a request for redispatch. UDP for IPv6 was unaware of this difference. Change __udp6_lib_rcv() to return a positive value for redispatch. Note that the socket's encap_rcv hook still needs to return a negative value to request dispatch, and in the case of IPv6 packets, adjust IP6CB(skb)->nhoff to identify the byte containing the next protocol. Signed-off-by: Bill Sommerfeld Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/ipv6/udp.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -899,11 +899,9 @@ int __udp6_lib_rcv(struct sk_buff *skb, ret = udpv6_queue_rcv_skb(sk, skb); sock_put(sk); - /* a return value > 0 means to resubmit the input, but - * it wants the return to be -protocol, or 0 - */ + /* a return value > 0 means to resubmit the input */ if (ret > 0) - return -ret; + return ret; return 0; }