From nobody Mon Apr 6 13:29:06 2026 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 91350C54EE9 for ; Tue, 27 Sep 2022 16:33:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbiI0Qde (ORCPT ); Tue, 27 Sep 2022 12:33:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbiI0Qdc (ORCPT ); Tue, 27 Sep 2022 12:33:32 -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 C91FA147CD8; Tue, 27 Sep 2022 09:33:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1664296413; x=1695832413; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=V15MrQFTDlO/YLh4gKR03P+7qtVWjx88QGQDMwXjI4o=; b=Qk2qpmh5oACBLcsQ7p8JIJ8Q0ip5sIKe+KWNmtploR8vvvlIt4K8d3i1 Umm0sbFnR3QGFYWlI3QJ0lxSS8xMWik01yL67S3Ujk6cNrEQJL5+cSpEr Lq1Bs7IGg471j4uYxZBZH18tfXr1V2nnJqmhXXIrDPjLutpe5EQaJCUm+ Y=; X-IronPort-AV: E=Sophos;i="5.93,349,1654560000"; d="scan'208";a="263719827" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-iad-1e-54c9d11f.us-east-1.amazon.com) ([10.25.36.210]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Sep 2022 16:13:54 +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-54c9d11f.us-east-1.amazon.com (Postfix) with ESMTPS id E1421C0ACC; Tue, 27 Sep 2022 16:13:50 +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 15.0.1497.38; Tue, 27 Sep 2022 16:13:43 +0000 Received: from 88665a182662.ant.amazon.com (10.43.160.214) 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 15.2.1118.12; Tue, 27 Sep 2022 16:13:40 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , , , Subject: [PATCH v1 net 5/5] tcp: Fix data races around icsk->icsk_af_ops. Date: Tue, 27 Sep 2022 09:12:09 -0700 Message-ID: <20220927161209.32939-6-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220927161209.32939-1-kuniyu@amazon.com> References: <20220927161209.32939-1-kuniyu@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.43.160.214] X-ClientProxiedBy: EX13D13UWA002.ant.amazon.com (10.43.160.172) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" IPV6_ADDRFORM changes icsk->icsk_af_ops under lock_sock(), but tcp_(get|set)sockopt() read it locklessly. To avoid load/store tearing, we need to add READ_ONCE() and WRITE_ONCE() for the reads and write. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima --- net/ipv4/tcp.c | 10 ++++++---- net/ipv6/ipv6_sockglue.c | 3 ++- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index e373dde1f46f..c86dd0ccef5b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3795,8 +3795,9 @@ int tcp_setsockopt(struct sock *sk, int level, int op= tname, sockptr_t optval, const struct inet_connection_sock *icsk =3D inet_csk(sk); =20 if (level !=3D SOL_TCP) - return icsk->icsk_af_ops->setsockopt(sk, level, optname, - optval, optlen); + /* IPV6_ADDRFORM can change icsk->icsk_af_ops under us. */ + return READ_ONCE(icsk->icsk_af_ops)->setsockopt(sk, level, optname, + optval, optlen); return do_tcp_setsockopt(sk, level, optname, optval, optlen); } EXPORT_SYMBOL(tcp_setsockopt); @@ -4394,8 +4395,9 @@ int tcp_getsockopt(struct sock *sk, int level, int op= tname, char __user *optval, struct inet_connection_sock *icsk =3D inet_csk(sk); =20 if (level !=3D SOL_TCP) - return icsk->icsk_af_ops->getsockopt(sk, level, optname, - optval, optlen); + /* IPV6_ADDRFORM can change icsk->icsk_af_ops under us. */ + return READ_ONCE(icsk->icsk_af_ops)->getsockopt(sk, level, optname, + optval, optlen); return do_tcp_getsockopt(sk, level, optname, optval, optlen); } EXPORT_SYMBOL(tcp_getsockopt); diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index a89db5872dc3..726d95859898 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -479,7 +479,8 @@ static int do_ipv6_setsockopt(struct sock *sk, int leve= l, int optname, =20 /* Paired with READ_ONCE(sk->sk_prot) in inet6_stream_ops */ WRITE_ONCE(sk->sk_prot, &tcp_prot); - icsk->icsk_af_ops =3D &ipv4_specific; + /* Paired with READ_ONCE() in tcp_(get|set)sockopt() */ + WRITE_ONCE(icsk->icsk_af_ops, &ipv4_specific); sk->sk_socket->ops =3D &inet_stream_ops; sk->sk_family =3D PF_INET; tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); --=20 2.30.2