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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7605C4360C for ; Sun, 6 Oct 2019 17:32:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1B3C217F9 for ; Sun, 6 Oct 2019 17:32:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383166; bh=AQXNI7teH9zY0Nt9DoZxtSd3C3DNrzzuqdtfyzz2xB0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bKNknCTS66itItF49NlAqCNgGwxJaGpbaNxcJejKr4T3eKthrOirIZl6kZ3BYS8Zu cK+JkR23z2b4bR7z3EJYyXbW5aJRtOlaNbaPDD5Z/a60MJMfEz7Dw7KmGXqSji7Cxk /hDd6oGxvfoCoeHYJDuhE9rlic54/I7azyTpUfH4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729643AbfJFRcq (ORCPT ); Sun, 6 Oct 2019 13:32:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:59208 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728484AbfJFRcn (ORCPT ); Sun, 6 Oct 2019 13:32:43 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E9D6221479; Sun, 6 Oct 2019 17:32:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383162; bh=AQXNI7teH9zY0Nt9DoZxtSd3C3DNrzzuqdtfyzz2xB0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IQ1G4bbIy0w9pybsGVjT4oh5YHFH+WbaiLaSnmgWAsfH1OrKgcJFxiS0b+sbthtVX G+QaXDErUhVSyonlEwdvaXP3XdEuL4UshmkqZAfLA6+w7jA/2CrDcp12kTcPY3N1/x 3yJjGm5+o93tM6mXCLOUoMTty0SdNiyiVd0x0LOw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Martin KaFai Lau , "David S. Miller" Subject: [PATCH 4.19 087/106] net: Unpublish sk from sk_reuseport_cb before call_rcu Date: Sun, 6 Oct 2019 19:21:33 +0200 Message-Id: <20191006171159.147815837@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191006171124.641144086@linuxfoundation.org> References: <20191006171124.641144086@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Martin KaFai Lau [ Upstream commit 8c7138b33e5c690c308b2a7085f6313fdcb3f616 ] The "reuse->sock[]" array is shared by multiple sockets. The going away sk must unpublish itself from "reuse->sock[]" before making call_rcu() call. However, this unpublish-action is currently done after a grace period and it may cause use-after-free. The fix is to move reuseport_detach_sock() to sk_destruct(). Due to the above reason, any socket with sk_reuseport_cb has to go through the rcu grace period before freeing it. It is a rather old bug (~3 yrs). The Fixes tag is not necessary the right commit but it is the one that introduced the SOCK_RCU_FREE logic and this fix is depending on it. Fixes: a4298e4522d6 ("net: add SOCK_RCU_FREE socket flag") Cc: Eric Dumazet Suggested-by: Eric Dumazet Signed-off-by: Martin KaFai Lau Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/sock.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1563,8 +1563,6 @@ static void __sk_destruct(struct rcu_hea sk_filter_uncharge(sk, filter); RCU_INIT_POINTER(sk->sk_filter, NULL); } - if (rcu_access_pointer(sk->sk_reuseport_cb)) - reuseport_detach_sock(sk); sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP); @@ -1587,7 +1585,14 @@ static void __sk_destruct(struct rcu_hea void sk_destruct(struct sock *sk) { - if (sock_flag(sk, SOCK_RCU_FREE)) + bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE); + + if (rcu_access_pointer(sk->sk_reuseport_cb)) { + reuseport_detach_sock(sk); + use_call_rcu = true; + } + + if (use_call_rcu) call_rcu(&sk->sk_rcu, __sk_destruct); else __sk_destruct(&sk->sk_rcu);