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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFCF6C04A68 for ; Wed, 27 Jul 2022 16:28:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236871AbiG0Q15 (ORCPT ); Wed, 27 Jul 2022 12:27:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235595AbiG0Q1P (ORCPT ); Wed, 27 Jul 2022 12:27:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A6CE4F1A7; Wed, 27 Jul 2022 09:24:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B0F27B821BC; Wed, 27 Jul 2022 16:24:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F309C433D6; Wed, 27 Jul 2022 16:23:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939040; bh=IS95Ux7y3Du7rX8+WAHdx5ZWxHFA3ifE1uxa9QhbhDA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jMap0XDOHwmhPcRL2i3xkITVKAi9y8LInfZffwN42yNhumCH+IRvskXZYwPjudZ46 liFvyN4f1Sepa34yRVaUHhI8GaaL2Yfz2QaVGqKg96cCqe3Inwr56Po0H3jOlWYoWx TJ2O57g+cZsRdv3TH7qcaXVEgTKCB1QTP5MMuaNk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 12/37] igmp: Fix a data-race around sysctl_igmp_max_memberships. Date: Wed, 27 Jul 2022 18:10:38 +0200 Message-Id: <20220727161001.357244881@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161000.822869853@linuxfoundation.org> References: <20220727161000.822869853@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuniyuki Iwashima [ Upstream commit 6305d821e3b9b5379d348528e5b5faf316383bc2 ] While reading sysctl_igmp_max_memberships, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/igmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 4b3875acc876..fd2c634eeee4 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2179,7 +2179,7 @@ int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr) count++; } err = -ENOBUFS; - if (count >= net->ipv4.sysctl_igmp_max_memberships) + if (count >= READ_ONCE(net->ipv4.sysctl_igmp_max_memberships)) goto done; iml = sock_kmalloc(sk, sizeof(*iml), GFP_KERNEL); if (!iml) -- 2.35.1