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=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 59F07C43219 for ; Sat, 4 May 2019 10:27:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DF412085A for ; Sat, 4 May 2019 10:27:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556965679; bh=e1o4mFFNofXkPR/ecgVDEav2/lkN45hLVFmaojZ77Vw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AIrH5qbCibF3PCSbnIBFZe9L8LLTClCId6HlaXxLUvnGpxv7Z3YooGrXROE87QsKb ko2Y4G+IJisrLLkoOqgJ+X9rBauKJ5o9H0JfNvM01YuiOdWb5QPhYi0Zti+NxnqKBe QkpPl3zbUx+Pt+zepKxxmQSekSQ0PO0n7V9AW7iA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728363AbfEDK16 (ORCPT ); Sat, 4 May 2019 06:27:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:38548 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727430AbfEDK1y (ORCPT ); Sat, 4 May 2019 06:27:54 -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 D37EA20862; Sat, 4 May 2019 10:27:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556965674; bh=e1o4mFFNofXkPR/ecgVDEav2/lkN45hLVFmaojZ77Vw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XzuTuAd9iICmfswOV5dO0zECeAB0YgZZ8ZKv/7wFjK0UomXR4dZ64F0Wflpnw0+DY RhCoxNnXFn5/eqBc32e3gr+DRJKmY7IBSd0v3JwWkL3prjkOLvFQ81o9XbIraaFPRK /6NiTcgCWsf7LpWtaODIWeYrhKLeuyUEsKKe91Ac= 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 4.19 07/23] l2tp: use rcu_dereference_sk_user_data() in l2tp_udp_encap_recv() Date: Sat, 4 May 2019 12:25:09 +0200 Message-Id: <20190504102451.803770039@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190504102451.512405835@linuxfoundation.org> References: <20190504102451.512405835@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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;