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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 6AA5DC43219 for ; Sat, 4 May 2019 10:29:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EABDC206BB for ; Sat, 4 May 2019 10:29:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556965764; bh=e1o4mFFNofXkPR/ecgVDEav2/lkN45hLVFmaojZ77Vw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=H+MUcOsS0K/ondZUWX+DBa0TPaT4vPHFBjYR77GNNht1Ep5HaX0xHjMH/n1UvxxYj J9jsJBa9h9V+hGrTyg05LrFH//o+GOd5Bvtz4N6G5nNOqa7hKRefAF3NGrapqbMyDW RqkaWRGfHK7eosBV+17D8g2XKnW6PlzAJ1D3JHlQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727901AbfEDK0w (ORCPT ); Sat, 4 May 2019 06:26:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:36654 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727920AbfEDK0w (ORCPT ); Sat, 4 May 2019 06:26:52 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F1ECC20870; Sat, 4 May 2019 10:26:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556965611; bh=e1o4mFFNofXkPR/ecgVDEav2/lkN45hLVFmaojZ77Vw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lN82J/E/LMPbH6StFNUKLMJeqJq8bvS1FMLzpZk8Xpe1+ZtADZ4YkRN7GbTpsWaj0 TrkAnpQB26+UG3JS0RTQMRjc9TF3BlbpoUxphPgddXeNYKMrCw1M9oPaYV5SjlQztG ttWg3p7JwzV/zYxd41sEzH7965Esv1MwgLtMEPlU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , James Chapman , "David S. Miller" Subject: [PATCH 5.0 07/32] l2tp: use rcu_dereference_sk_user_data() in l2tp_udp_encap_recv() Date: Sat, 4 May 2019 12:24:52 +0200 Message-Id: <20190504102452.764103982@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190504102452.523724210@linuxfoundation.org> References: <20190504102452.523724210@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit c1c477217882c610a2ba0268f5faf36c9c092528 ] Canonical way to fetch sk_user_data from an encap_rcv() handler called from UDP stack in rcu protected section is to use rcu_dereference_sk_user_data(), otherwise compiler might read it multiple times. Fixes: d00fa9adc528 ("il2tp: fix races with tunnel socket close") Signed-off-by: Eric Dumazet Cc: James Chapman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -909,7 +909,7 @@ int l2tp_udp_encap_recv(struct sock *sk, { struct l2tp_tunnel *tunnel; - tunnel = l2tp_tunnel(sk); + tunnel = rcu_dereference_sk_user_data(sk); if (tunnel == NULL) goto pass_up;