From patchwork Wed Jul 13 20:51:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12917098 X-Patchwork-Delegate: kuba@kernel.org 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 AE832C43334 for ; Wed, 13 Jul 2022 20:53:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236806AbiGMUxR (ORCPT ); Wed, 13 Jul 2022 16:53:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236631AbiGMUxO (ORCPT ); Wed, 13 Jul 2022 16:53:14 -0400 Received: from smtp-fw-9102.amazon.com (smtp-fw-9102.amazon.com [207.171.184.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A67531386 for ; Wed, 13 Jul 2022 13:53:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657745594; x=1689281594; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Taebn04JWrfcT24uXktxMagD5ip/aYBqEm3N533rhIw=; b=UzUmup3pZav6fwPzxEaKEvdYVKpSuPqv5ndTezLqq7hUQ54qZxln3R6c xCWsysU9YIt6OIMuwU3kt5sc4YnguLd3+4iGdzi0N1PqfALgtE58DWZ5s 39q2yGcE2WIsG1+95ISSzsPFBjs/Nr56a43i5mAEQPeRGm4cbqK6dI9vd c=; X-IronPort-AV: E=Sophos;i="5.92,269,1650931200"; d="scan'208";a="237978949" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-iad-1e-b69ea591.us-east-1.amazon.com) ([10.25.36.210]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP; 13 Jul 2022 20:53:13 +0000 Received: from EX13MTAUWB001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan2.iad.amazon.com [10.40.163.34]) by email-inbound-relay-iad-1e-b69ea591.us-east-1.amazon.com (Postfix) with ESMTPS id 627CCC08DD; Wed, 13 Jul 2022 20:53:10 +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, 13 Jul 2022 20:53:09 +0000 Received: from 88665a182662.ant.amazon.com.com (10.43.160.222) 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, 13 Jul 2022 20:53:06 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , , Hannes Frederic Sowa Subject: [PATCH v1 net 03/15] ip: Fix data-races around sysctl_ip_fwd_use_pmtu. Date: Wed, 13 Jul 2022 13:51:53 -0700 Message-ID: <20220713205205.15735-4-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220713205205.15735-1-kuniyu@amazon.com> References: <20220713205205.15735-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.160.222] X-ClientProxiedBy: EX13D29UWA002.ant.amazon.com (10.43.160.63) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org While reading sysctl_ip_fwd_use_pmtu, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: f87c10a8aa1e ("ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing") Signed-off-by: Kuniyuki Iwashima --- CC: Hannes Frederic Sowa --- include/net/ip.h | 2 +- net/ipv4/route.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/net/ip.h b/include/net/ip.h index 26fffda78cca..05fe313f72fa 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -446,7 +446,7 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, struct net *net = dev_net(dst->dev); unsigned int mtu; - if (net->ipv4.sysctl_ip_fwd_use_pmtu || + if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) || ip_mtu_locked(dst) || !forwarding) { mtu = rt->rt_pmtu; diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 356f535f3443..91c4f60de75a 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1398,7 +1398,7 @@ u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) struct fib_info *fi = res->fi; u32 mtu = 0; - if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || + if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) || fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) mtu = fi->fib_mtu;