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 526C0C19F2B for ; Wed, 27 Jul 2022 16:40:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239467AbiG0QkY (ORCPT ); Wed, 27 Jul 2022 12:40:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238729AbiG0Qj2 (ORCPT ); Wed, 27 Jul 2022 12:39:28 -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 37A755A2D6; Wed, 27 Jul 2022 09:29:01 -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 ams.source.kernel.org (Postfix) with ESMTPS id A686EB821C8; Wed, 27 Jul 2022 16:29:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7543C433C1; Wed, 27 Jul 2022 16:28:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939339; bh=8p7JnuXE9u0JMF/wryTpy0J+AHjq54jUbxHU1zH7/Fo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0/i2s2Z1pyoRdufFwKyG8LwJDz7WRt3iDD6dxBElVmiDpAqq5axWf5aANzmCWGnc2 K6Tdq1GgD+THoM36PaakxZD+ec9AQpQ02LP3Wrj94MKDZPNTSEeQICVO1tAkY3FAwa xK1vyP/6CTB0SXpNiZM7mzxhLhc8KceXIBHjUAkI= 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 5.4 34/87] tcp: Fix data-races around some timeout sysctl knobs. Date: Wed, 27 Jul 2022 18:10:27 +0200 Message-Id: <20220727161010.445073647@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161008.993711844@linuxfoundation.org> References: <20220727161008.993711844@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 39e24435a776e9de5c6dd188836cf2523547804b ] While reading these sysctl knobs, they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. - tcp_retries1 - tcp_retries2 - tcp_orphan_retries - tcp_fin_timeout Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/tcp.h | 3 ++- net/ipv4/tcp.c | 2 +- net/ipv4/tcp_output.c | 2 +- net/ipv4/tcp_timer.c | 10 +++++----- 4 files changed, 9 insertions(+), 8 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 65be8bd1f0f4..96dae0937998 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1465,7 +1465,8 @@ static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) static inline int tcp_fin_time(const struct sock *sk) { - int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout; + int fin_timeout = tcp_sk(sk)->linger2 ? : + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); const int rto = inet_csk(sk)->icsk_rto; if (fin_timeout < (rto << 2) - (rto >> 1)) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 790246011fff..333d221e0717 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3466,7 +3466,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level, case TCP_LINGER2: val = tp->linger2; if (val >= 0) - val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ; + val = (val ? : READ_ONCE(net->ipv4.sysctl_tcp_fin_timeout)) / HZ; break; case TCP_DEFER_ACCEPT: val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 9bfe6965b873..8b602a202acb 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3847,7 +3847,7 @@ void tcp_send_probe0(struct sock *sk) icsk->icsk_probes_out++; if (err <= 0) { - if (icsk->icsk_backoff < net->ipv4.sysctl_tcp_retries2) + if (icsk->icsk_backoff < READ_ONCE(net->ipv4.sysctl_tcp_retries2)) icsk->icsk_backoff++; timeout = tcp_probe0_when(sk, TCP_RTO_MAX); } else { diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index c48aeaef3ec7..26da44e196ed 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -143,7 +143,7 @@ static int tcp_out_of_resources(struct sock *sk, bool do_reset) */ static int tcp_orphan_retries(struct sock *sk, bool alive) { - int retries = sock_net(sk)->ipv4.sysctl_tcp_orphan_retries; /* May be zero. */ + int retries = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_orphan_retries); /* May be zero. */ /* We know from an ICMP that something is wrong. */ if (sk->sk_err_soft && !alive) @@ -245,7 +245,7 @@ static int tcp_write_timeout(struct sock *sk) retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; expired = icsk->icsk_retransmits >= retry_until; } else { - if (retransmits_timed_out(sk, net->ipv4.sysctl_tcp_retries1, 0)) { + if (retransmits_timed_out(sk, READ_ONCE(net->ipv4.sysctl_tcp_retries1), 0)) { /* Black hole detection */ tcp_mtu_probing(icsk, sk); @@ -254,7 +254,7 @@ static int tcp_write_timeout(struct sock *sk) sk_rethink_txhash(sk); } - retry_until = net->ipv4.sysctl_tcp_retries2; + retry_until = READ_ONCE(net->ipv4.sysctl_tcp_retries2); if (sock_flag(sk, SOCK_DEAD)) { const bool alive = icsk->icsk_rto < TCP_RTO_MAX; @@ -381,7 +381,7 @@ static void tcp_probe_timer(struct sock *sk) msecs_to_jiffies(icsk->icsk_user_timeout)) goto abort; - max_probes = sock_net(sk)->ipv4.sysctl_tcp_retries2; + max_probes = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_retries2); if (sock_flag(sk, SOCK_DEAD)) { const bool alive = inet_csk_rto_backoff(icsk, TCP_RTO_MAX) < TCP_RTO_MAX; @@ -580,7 +580,7 @@ void tcp_retransmit_timer(struct sock *sk) } inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, tcp_clamp_rto_to_user_timeout(sk), TCP_RTO_MAX); - if (retransmits_timed_out(sk, net->ipv4.sysctl_tcp_retries1 + 1, 0)) + if (retransmits_timed_out(sk, READ_ONCE(net->ipv4.sysctl_tcp_retries1) + 1, 0)) __sk_dst_reset(sk); out:; -- 2.35.1