From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sabrina Dubroca Subject: Re: [PATCH net] ipv6/ndisc: Preserve IPv6 control buffer if protocol error handlers are called Date: Fri, 26 Oct 2018 17:00:15 +0200 Message-ID: <20181026150015.GA17914@bistromath.localdomain> References: <7acb12cb7a35c7a5f9670fc5b1373610b4d5ed67.1540384081.git.sbrivio@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: "David S. Miller" , Hideaki YOSHIFUJI , netdev@vger.kernel.org To: Stefano Brivio Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60584 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726195AbeJZXhR (ORCPT ); Fri, 26 Oct 2018 19:37:17 -0400 Content-Disposition: inline In-Reply-To: <7acb12cb7a35c7a5f9670fc5b1373610b4d5ed67.1540384081.git.sbrivio@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: 2018-10-24, 14:37:21 +0200, Stefano Brivio wrote: > Commit a61bbcf28a8c ("[NET]: Store skb->timestamp as offset to a base > timestamp") introduces a neighbour control buffer and zeroes it out in > ndisc_rcv(), as ndisc_recv_ns() uses it. > > Commit f2776ff04722 ("[IPV6]: Fix address/interface handling in UDP and > DCCP, according to the scoping architecture.") introduces the usage of the > IPv6 control buffer in protocol error handlers (e.g. inet6_iif() in > present-day __udp6_lib_err()). > > Now, with commit b94f1c0904da ("ipv6: Use icmpv6_notify() to propagate > redirect, instead of rt6_redirect()."), we call protocol error handlers > from ndisc_redirect_rcv(), after the control buffer is already stolen and > some parts are already zeroed out. This implies that inet6_iif() on this > path will always return zero. > > This gives unexpected results on UDP socket lookup in __udp6_lib_err(), as > we might actually need to match sockets for a given interface. > > Instead of always claiming the control buffer in ndisc_rcv(), do that only > when needed. > > Fixes: b94f1c0904da ("ipv6: Use icmpv6_notify() to propagate redirect, instead of rt6_redirect().") > Signed-off-by: Stefano Brivio Reviewed-by: Sabrina Dubroca -- Sabrina