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 64C2FC433EF for ; Wed, 6 Jul 2022 05:25:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231665AbiGFFZp (ORCPT ); Wed, 6 Jul 2022 01:25:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231659AbiGFFZ0 (ORCPT ); Wed, 6 Jul 2022 01:25:26 -0400 Received: from smtp-fw-80007.amazon.com (smtp-fw-80007.amazon.com [99.78.197.218]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C33AB21832; Tue, 5 Jul 2022 22:25:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657085125; x=1688621125; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=PAHZJLR0VKsPtaE3Lf0xNPA4gDWSGnYveB872veX8og=; b=chbTU772vvFcaMfoyjw/Jo8SCDgDOnxTbJaaQVFR2a+PXosDmCkXqxZA V6UgjhKPY2+pUgNaz6g4Y/6sjCkGChPRxtqOmYY8pUUnxzbqvlodwJSC/ ukmYNt9kSU5ivK+ug7Nf3ZzsMKojPeka96Af+TtxZiI+lCQoleemEzieq A=; X-IronPort-AV: E=Sophos;i="5.92,248,1650931200"; d="scan'208";a="105282730" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-pdx-2a-6fd66c4a.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP; 06 Jul 2022 05:25:25 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-pdx-2a-6fd66c4a.us-west-2.amazon.com (Postfix) with ESMTPS id 2598583A35; Wed, 6 Jul 2022 05:25:25 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.207) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Wed, 6 Jul 2022 05:25:24 +0000 Received: from 88665a182662.ant.amazon.com (10.43.162.55) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.9; Wed, 6 Jul 2022 05:25:22 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Luis Chamberlain , Kees Cook , Iurii Zaikin CC: Kuniyuki Iwashima , Kuniyuki Iwashima , , Subject: [PATCH v1 net 15/16] icmp: Fix data-races around sysctl. Date: Tue, 5 Jul 2022 22:21:29 -0700 Message-ID: <20220706052130.16368-16-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220706052130.16368-1-kuniyu@amazon.com> References: <20220706052130.16368-1-kuniyu@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.43.162.55] X-ClientProxiedBy: EX13D18UWA004.ant.amazon.com (10.43.160.45) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While reading sysctl variables, it can be changed concurrently. So, we need to add READ_ONCE(). Then we can set proc_dointvec_minmax_lockless() as the handler to mark it safe. Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Signed-off-by: Kuniyuki Iwashima --- net/ipv4/icmp.c | 5 +++-- net/ipv4/sysctl_net_ipv4.c | 4 ++-- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index efea0e796f06..0f9e61d29f73 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -253,11 +253,12 @@ bool icmp_global_allow(void) spin_lock(&icmp_global.lock); delta = min_t(u32, now - icmp_global.stamp, HZ); if (delta >= HZ / 50) { - incr = sysctl_icmp_msgs_per_sec * delta / HZ ; + incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; if (incr) WRITE_ONCE(icmp_global.stamp, now); } - credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst); + credit = min_t(u32, icmp_global.credit + incr, + READ_ONCE(sysctl_icmp_msgs_burst)); if (credit) { /* We want to use a credit of one in average, but need to randomize * it for security reasons. diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 706795a3b369..3b1d18be0857 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -555,7 +555,7 @@ static struct ctl_table ipv4_table[] = { .data = &sysctl_icmp_msgs_per_sec, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_dointvec_minmax_lockless, .extra1 = SYSCTL_ZERO, }, { @@ -563,7 +563,7 @@ static struct ctl_table ipv4_table[] = { .data = &sysctl_icmp_msgs_burst, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_dointvec_minmax_lockless, .extra1 = SYSCTL_ZERO, }, { -- 2.30.2