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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D127EC433FF for ; Mon, 12 Aug 2019 22:46:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9616C20665 for ; Mon, 12 Aug 2019 22:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726993AbfHLWqF (ORCPT ); Mon, 12 Aug 2019 18:46:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33482 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726488AbfHLWqF (ORCPT ); Mon, 12 Aug 2019 18:46:05 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9443A30BCB85; Mon, 12 Aug 2019 22:46:05 +0000 (UTC) Received: from epycfail.redhat.com (unknown [10.36.112.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id 865E8842A2; Mon, 12 Aug 2019 22:46:03 +0000 (UTC) From: Stefano Brivio To: David Miller Cc: Guillaume Nault , Hangbin Liu , Eric Dumazet , =?UTF-8?q?Linus=20L=C3=BCssing?= , netdev@vger.kernel.org Subject: [PATCH net] ipv6: Fix return value of ipv6_mc_may_pull() for malformed packets Date: Tue, 13 Aug 2019 00:46:01 +0200 Message-Id: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Mon, 12 Aug 2019 22:46:05 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Commit ba5ea614622d ("bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls") replaces direct calls to pskb_may_pull() in br_ipv6_multicast_mld2_report() with calls to ipv6_mc_may_pull(), that returns -EINVAL on buffers too short to be valid IPv6 packets, while maintaining the previous handling of the return code. This leads to the direct opposite of the intended effect: if the packet is malformed, -EINVAL evaluates as true, and we'll happily proceed with the processing. Return 0 if the packet is too short, in the same way as this was fixed for IPv4 by commit 083b78a9ed64 ("ip: fix ip_mc_may_pull() return value"). I don't have a reproducer for this, unlike the one referred to by the IPv4 commit, but this is clearly broken. Fixes: ba5ea614622d ("bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls") Signed-off-by: Stefano Brivio --- include/net/addrconf.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/addrconf.h b/include/net/addrconf.h index becdad576859..3f62b347b04a 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -206,7 +206,7 @@ static inline int ipv6_mc_may_pull(struct sk_buff *skb, unsigned int len) { if (skb_transport_offset(skb) + ipv6_transport_len(skb) < len) - return -EINVAL; + return 0; return pskb_may_pull(skb, len); } -- 2.20.1