From patchwork Tue Oct 27 13:44:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 289573 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=-14.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 9AC12C838A9 for ; Tue, 27 Oct 2020 15:48:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41079223B0 for ; Tue, 27 Oct 2020 15:48:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603813730; bh=9SyeiN8tusMmO57swdaEQsBCuhOH7kDgp6HiuibHQME=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XGIFckKHKAKAbLewa3FH34mTU/gnWCEy9lOKmshQ3oR488c+uzUGtoCXOWwqJt0K7 yETo9oJ5NCVgY6391CmTtKWuaPrd1e4WpThtrVsvfOGrrJNiMbGrW0bz9ThGAUT3qQ iHtNw8WmhfkOTVw0zsIHGsjcPSHhyWeK/Lwk7HoE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1800896AbgJ0Pso (ORCPT ); Tue, 27 Oct 2020 11:48:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:55328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1796375AbgJ0PR4 (ORCPT ); Tue, 27 Oct 2020 11:17:56 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 87FE320728; Tue, 27 Oct 2020 15:17:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603811876; bh=9SyeiN8tusMmO57swdaEQsBCuhOH7kDgp6HiuibHQME=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Ri/EHTQpyB7nfxvB/XUCv8r4xfhhz0tsyBcB0Yr88kTeXtrFKFdF9WBlG8PmBSei PfCJ2Q95eUEA3mAd3qcr4geWy48GxyLlf73YkvBpRr7G9bETXxHopOGOS0jBAKP3FV yDx7uwmX/Y+JGYUSLiSPFACL2lJVAuAtUK0ynWy4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mat Martineau , Paolo Abeni , Jakub Kicinski Subject: [PATCH 5.9 006/757] mptcp: fix fallback for MP_JOIN subflows Date: Tue, 27 Oct 2020 14:44:16 +0100 Message-Id: <20201027135450.829684670@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135450.497324313@linuxfoundation.org> References: <20201027135450.497324313@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paolo Abeni [ Upstream commit d582484726c4c46c8580923e855665fb91e3463e ] Additional/MP_JOIN subflows that do not pass some initial handshake tests currently causes fallback to TCP. That is an RFC violation: we should instead reset the subflow and leave the the msk untouched. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/91 Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Reviewed-by: Mat Martineau Signed-off-by: Paolo Abeni Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/options.c | 32 +++++++++++++++++++++++++------- net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 10 ++++++++-- 3 files changed, 34 insertions(+), 9 deletions(-) --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -626,6 +626,12 @@ bool mptcp_established_options(struct so if (unlikely(mptcp_check_fallback(sk))) return false; + /* prevent adding of any MPTCP related options on reset packet + * until we support MP_TCPRST/MP_FASTCLOSE + */ + if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) + return false; + if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts)) ret = true; else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining, @@ -676,7 +682,7 @@ bool mptcp_synack_options(const struct r return false; } -static bool check_fully_established(struct mptcp_sock *msk, struct sock *sk, +static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, struct mptcp_subflow_context *subflow, struct sk_buff *skb, struct mptcp_options_received *mp_opt) @@ -693,15 +699,20 @@ static bool check_fully_established(stru TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && subflow->mp_join && mp_opt->mp_join && READ_ONCE(msk->pm.server_side)) - tcp_send_ack(sk); + tcp_send_ack(ssk); goto fully_established; } - /* we should process OoO packets before the first subflow is fully - * established, but not expected for MP_JOIN subflows + /* we must process OoO packets before the first subflow is fully + * established. OoO packets are instead a protocol violation + * for MP_JOIN subflows as the peer must not send any data + * before receiving the forth ack - cfr. RFC 8684 section 3.2. */ - if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) + if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { + if (subflow->mp_join) + goto reset; return subflow->mp_capable; + } if (mp_opt->dss && mp_opt->use_ack) { /* subflows are fully established as soon as we get any @@ -713,9 +724,12 @@ static bool check_fully_established(stru } /* If the first established packet does not contain MP_CAPABLE + data - * then fallback to TCP + * then fallback to TCP. Fallback scenarios requires a reset for + * MP_JOIN subflows. */ if (!mp_opt->mp_capable) { + if (subflow->mp_join) + goto reset; subflow->mp_capable = 0; pr_fallback(msk); __mptcp_do_fallback(msk); @@ -732,12 +746,16 @@ fully_established: subflow->pm_notified = 1; if (subflow->mp_join) { - clear_3rdack_retransmission(sk); + clear_3rdack_retransmission(ssk); mptcp_pm_subflow_established(msk, subflow); } else { mptcp_pm_fully_established(msk); } return true; + +reset: + mptcp_subflow_reset(ssk); + return false; } static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -348,6 +348,7 @@ void mptcp_subflow_fully_established(str struct mptcp_options_received *mp_opt); bool mptcp_subflow_data_available(struct sock *sk); void __init mptcp_subflow_init(void); +void mptcp_subflow_reset(struct sock *ssk); /* called with sk socket lock held */ int __mptcp_subflow_connect(struct sock *sk, int ifindex, --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -270,6 +270,13 @@ static bool subflow_thmac_valid(struct m return thmac == subflow->thmac; } +void mptcp_subflow_reset(struct sock *ssk) +{ + tcp_set_state(ssk, TCP_CLOSE); + tcp_send_active_reset(ssk, GFP_ATOMIC); + tcp_done(ssk); +} + static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); @@ -342,8 +349,7 @@ fallback: return; do_reset: - tcp_send_active_reset(sk, GFP_ATOMIC); - tcp_done(sk); + mptcp_subflow_reset(sk); } struct request_sock_ops mptcp_subflow_request_sock_ops;