From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98A91C433DF for ; Mon, 6 Jul 2020 17:45:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 748992080D for ; Mon, 6 Jul 2020 17:45:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594057514; bh=KknJPOB/p48fDu4wmZ5eaPAJdL9VYIP2U/8CNi8iAHY=; h=From:To:Cc:Subject:Date:List-ID:From; b=RVf9B3LM3lw4JZTidbzKrigTQIkxPPxpQbqyoxhLfgT0JLeYVLV3skawivD2/wbSl 3+6MDVOGSif09ZFDJrOxhNci3ONWhCUuvXMlEseB19pU1FNPh7VPHbeR+6tq4bxFfu aWp8xzIxpwqYWMTacLG/5YEjkm0k/uMxe4YkdEog= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729759AbgGFRpM (ORCPT ); Mon, 6 Jul 2020 13:45:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:38720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729550AbgGFRpK (ORCPT ); Mon, 6 Jul 2020 13:45:10 -0400 Received: from C02YQ0RWLVCF.internal.digitalocean.com (c-73-181-34-237.hsd1.co.comcast.net [73.181.34.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EF788208D5; Mon, 6 Jul 2020 17:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594057509; bh=KknJPOB/p48fDu4wmZ5eaPAJdL9VYIP2U/8CNi8iAHY=; h=From:To:Cc:Subject:Date:From; b=mJOgAX9s8hLBuiS/URQlWqArbHNGQfp946mTDxoeuaqOIWgJV0Dkfd+PkWShu5sgc mX5f9tdHJKTPUDZhuzpbm5AV+YpLmbtFwKKRkU8hz5Vy/fSdO6SaSZ2JDFnc8azlrA uGLd0Ycz6kymHaCBZsHkjJd35Geq+2V8wNT7I81o= From: David Ahern To: netdev@vger.kernel.org, kuba@kernel.org, davem@davemloft.net Cc: brak@choopa.com, David Ahern Subject: [PATCH v2 net] ipv6: fib6_select_path can not use out path for nexthop objects Date: Mon, 6 Jul 2020 11:45:07 -0600 Message-Id: <20200706174507.18556-1-dsahern@kernel.org> X-Mailer: git-send-email 2.21.1 (Apple Git-122.3) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Brian reported a crash in IPv6 code when using rpfilter with a setup running FRR and external nexthop objects. The root cause of the crash is fib6_select_path setting fib6_nh in the result to NULL because of an improper check for nexthop objects. More specifically, rpfilter invokes ip6_route_lookup with flowi6_oif set causing fib6_select_path to be called with have_oif_match set. fib6_select_path has early check on have_oif_match and jumps to the out label which presumes a builtin fib6_nh. This path is invalid for nexthop objects; for external nexthops fib6_select_path needs to just return if the fib6_nh has already been set in the result otherwise it returns after the call to nexthop_path_fib6_result. Update the check on have_oif_match to not bail on external nexthops. Update selftests for this problem. Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info") Reported-by: Brian Rak Signed-off-by: David Ahern --- v2 - for multipath nexthops path may already be set; do not want to overwrite that selection based on hash net/ipv6/route.c | 5 ++++- tools/testing/selftests/net/fib_nexthops.sh | 13 +++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 82cbb46a2a4f..ea0be7cf3d93 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -431,9 +431,12 @@ void fib6_select_path(const struct net *net, struct fib6_result *res, struct fib6_info *sibling, *next_sibling; struct fib6_info *match = res->f6i; - if ((!match->fib6_nsiblings && !match->nh) || have_oif_match) + if (!match->nh && (!match->fib6_nsiblings || have_oif_match)) goto out; + if (match->nh && have_oif_match && res->nh) + return; + /* We might have already computed the hash for ICMPv6 errors. In such * case it will always be non-zero. Otherwise now is the time to do it. */ diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh index dee567f7576a..22dc2f3d428b 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -747,6 +747,19 @@ ipv6_fcnal_runtime() run_cmd "$IP nexthop add id 86 via 2001:db8:91::2 dev veth1" run_cmd "$IP ro add 2001:db8:101::1/128 nhid 81" + # rpfilter and default route + $IP nexthop flush >/dev/null 2>&1 + run_cmd "ip netns exec me ip6tables -t mangle -I PREROUTING 1 -m rpfilter --invert -j DROP" + run_cmd "$IP nexthop add id 91 via 2001:db8:91::2 dev veth1" + run_cmd "$IP nexthop add id 92 via 2001:db8:92::2 dev veth3" + run_cmd "$IP nexthop add id 93 group 91/92" + run_cmd "$IP -6 ro add default nhid 91" + run_cmd "ip netns exec me ping -c1 -w1 2001:db8:101::1" + log_test $? 0 "Nexthop with default route and rpfilter" + run_cmd "$IP -6 ro replace default nhid 93" + run_cmd "ip netns exec me ping -c1 -w1 2001:db8:101::1" + log_test $? 0 "Nexthop with multipath default route and rpfilter" + # TO-DO: # existing route with old nexthop; append route with new nexthop # existing route with old nexthop; replace route with new -- 2.17.1