Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752997AbbEEBZR (ORCPT ); Mon, 4 May 2015 21:25:17 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50937 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752149AbbEEBV6 (ORCPT ); Mon, 4 May 2015 21:21:58 -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" , "Fernando Gont" , "Hannes Frederic Sowa" , "Hagen Paul Pfeifer" Date: Tue, 05 May 2015 02:16:39 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 187/221] ipv6: stop sending PTB packets for MTU < 1280 In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 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: 1667 Lines: 49 3.2.69-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Hagen Paul Pfeifer [ Upstream commit 9d289715eb5c252ae15bd547cb252ca547a3c4f2 ] Reduce the attack vector and stop generating IPv6 Fragment Header for paths with an MTU smaller than the minimum required IPv6 MTU size (1280 byte) - called atomic fragments. See IETF I-D "Deprecating the Generation of IPv6 Atomic Fragments" [1] for more information and how this "feature" can be misused. [1] https://tools.ietf.org/html/draft-ietf-6man-deprecate-atomfrag-generation-00 Signed-off-by: Fernando Gont Signed-off-by: Hagen Paul Pfeifer Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/ipv6/route.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1018,12 +1018,9 @@ static void ip6_rt_update_pmtu(struct ds if (mtu < dst_mtu(dst) && rt6->rt6i_dst.plen == 128) { rt6->rt6i_flags |= RTF_MODIFIED; - if (mtu < IPV6_MIN_MTU) { - u32 features = dst_metric(dst, RTAX_FEATURES); + if (mtu < IPV6_MIN_MTU) mtu = IPV6_MIN_MTU; - features |= RTAX_FEATURE_ALLFRAG; - dst_metric_set(dst, RTAX_FEATURES, features); - } + dst_metric_set(dst, RTAX_MTU, mtu); } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/