From patchwork Wed Dec 9 11:03:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 340868 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 F3F9DC433FE for ; Wed, 9 Dec 2020 11:05:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD07B2336F for ; Wed, 9 Dec 2020 11:05:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730339AbgLILFY (ORCPT ); Wed, 9 Dec 2020 06:05:24 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:36334 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730276AbgLILFP (ORCPT ); Wed, 9 Dec 2020 06:05:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607511829; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vX/GEa5LkEasf8ePL37UaPn1sCbO4jCR1KoS38zKeAg=; b=aXijdIHr6MzMF4/zcHcKYTtBJqb+Mk3xk9n38KXZ8zriJMWwnrdhg4Iu2ehaJzYERN5fDT YmkHdVO9UYCTzevx4oUe/hQ+GpgSnD9O/3KIMFyR4bfqtfVVOGNUvbsWtQflbN1du75Xvz fUtjSvGm59wXDu01eVns7RSzr+fUyYI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-172-acYpaiTmPhKJimAituROaQ-1; Wed, 09 Dec 2020 06:03:47 -0500 X-MC-Unique: acYpaiTmPhKJimAituROaQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 433E7107ACE3; Wed, 9 Dec 2020 11:03:46 +0000 (UTC) Received: from gerbillo.redhat.com (ovpn-112-45.ams2.redhat.com [10.36.112.45]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1194819C78; Wed, 9 Dec 2020 11:03:44 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: "David S. Miller" , Jakub Kicinski , mptcp@lists.01.org Subject: [PATCH net-next 3/3] mptcp: be careful on subflows shutdown Date: Wed, 9 Dec 2020 12:03:31 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When the workqueue disposes of the msk, the subflows can still receive some data from the peer after __mptcp_close_ssk() completes. The above could trigger a race between the msk receive path and the msk destruction. Acquiring the mptcp_data_lock() in __mptcp_destroy_sock() will not save the day: the rx path could be reached even after msk destruction completes. Instead use the subflow 'disposable' flag to prevent entering the msk receive path after __mptcp_close_ssk(). Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Reviewed-by: Matthieu Baerts Signed-off-by: Paolo Abeni --- net/mptcp/protocol.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 4e29dcf17ecd..2540d82742ac 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -701,6 +701,13 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) int sk_rbuf, ssk_rbuf; bool wake; + /* The peer can send data while we are shutting down this + * subflow at msk destruction time, but we must avoid enqueuing + * more data to the msk receive queue + */ + if (unlikely(subflow->disposable)) + return; + /* move_skbs_to_msk below can legitly clear the data_avail flag, * but we will need later to properly woke the reader, cache its * value @@ -2119,6 +2126,8 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, sock_orphan(ssk); } + subflow->disposable = 1; + /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops * the ssk has been already destroyed, we just need to release the * reference owned by msk; @@ -2126,8 +2135,7 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, if (!inet_csk(ssk)->icsk_ulp_ops) { kfree_rcu(subflow, rcu); } else { - /* otherwise ask tcp do dispose of ssk and subflow ctx */ - subflow->disposable = 1; + /* otherwise tcp will dispose of the ssk and subflow ctx */ __tcp_close(ssk, 0); /* close acquired an extra ref */