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 EBAD7C04A68 for ; Wed, 27 Jul 2022 16:22:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235546AbiG0QWx (ORCPT ); Wed, 27 Jul 2022 12:22:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234732AbiG0QWC (ORCPT ); Wed, 27 Jul 2022 12:22:02 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBAD231238; Wed, 27 Jul 2022 09:22:01 -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 sin.source.kernel.org (Postfix) with ESMTPS id A38FDCE2304; Wed, 27 Jul 2022 16:21:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F1D9C433C1; Wed, 27 Jul 2022 16:21:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658938918; bh=baCgCy56YObxzhgX2L4La7FM8mD+ITUsB5YBk92O+E4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WnLFJbvYmfmgTmfHCuULrJWxPzfXM1FfxM7ysPyd00NLDPUF00rdo5ejKI9v+cHnh Hg6l9kXFhFCBIfYPaF/TWE8TtFikERqVponiOvopIPzE+2RYRXEb4YgHVL8z2fHR/Q MSJ5Q0TlsFwE9WfymxrOjWIJG15L3VrDdc2SdZgs= 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 4.9 14/26] igmp: Fix a data-race around sysctl_igmp_max_memberships. Date: Wed, 27 Jul 2022 18:10:43 +0200 Message-Id: <20220727160959.689789254@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727160959.122591422@linuxfoundation.org> References: <20220727160959.122591422@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 6e217424e0ff..3c09bee931b7 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2171,7 +2171,7 @@ 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