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=-19.5 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,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 98213C19F3A for ; Mon, 26 Jul 2021 16:13:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 831A7604AC for ; Mon, 26 Jul 2021 16:13:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233464AbhGZPcz (ORCPT ); Mon, 26 Jul 2021 11:32:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:40886 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237890AbhGZP32 (ORCPT ); Mon, 26 Jul 2021 11:29:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AA773610A0; Mon, 26 Jul 2021 16:09:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627315769; bh=B/W8a58DraerEqWvfxB4VTt7LN+Yqi+LHuu3f9dsR+E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Azh08xLYDvLHmx/yi2n11I5BVucJvBMCdLG4q6aqxpcXpgtjv60gFZ/e/4kLsu9zm DN3um8uCbMWkKqmU7w0PcOrF5Vm6vNcnBAqGB7B/b2YUhzGRcuo4U8wy9y4g2Mb/88 jeet63z4M4Vrwbi+C2tfeylk2au5DznzvYLVE1Jo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jianguo Wu , Mat Martineau , "David S. Miller" , Sasha Levin Subject: [PATCH 5.13 032/223] mptcp: fix syncookie process if mptcp can not_accept new subflow Date: Mon, 26 Jul 2021 17:37:04 +0200 Message-Id: <20210726153847.305206867@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210726153846.245305071@linuxfoundation.org> References: <20210726153846.245305071@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: stable@vger.kernel.org From: Jianguo Wu [ Upstream commit 8547ea5f52dd8ef19b69c25c41b1415481b3503b ] Lots of "TCP: tcp_fin: Impossible, sk->sk_state=7" in client side when doing stress testing using wrk and webfsd. There are at least two cases may trigger this warning: 1.mptcp is in syncookie, and server recv MP_JOIN SYN request, in subflow_check_req(), the mptcp_can_accept_new_subflow() return false, so subflow_init_req_cookie_join_save() isn't called, i.e. not store the data present in the MP_JOIN syn request and the random nonce in hash table - join_entries[], but still send synack. When recv 3rd-ack, mptcp_token_join_cookie_init_state() will return false, and 3rd-ack is dropped, then if mptcp conn is closed by client, client will send a DATA_FIN and a MPTCP FIN, the DATA_FIN doesn't have MP_CAPABLE or MP_JOIN, so mptcp_subflow_init_cookie_req() will return 0, and pass the cookie check, MP_JOIN request is fallback to normal TCP. Server will send a TCP FIN if closed, in client side, when process TCP FIN, it will do reset, the code path is: tcp_data_queue()->mptcp_incoming_options() ->check_fully_established()->mptcp_subflow_reset(). mptcp_subflow_reset() will set sock state to TCP_CLOSE, so tcp_fin will hit TCP_CLOSE, and print the warning. 2.mptcp is in syncookie, and server recv 3rd-ack, in mptcp_subflow_init_cookie_req(), mptcp_can_accept_new_subflow() return false, and subflow_req->mp_join is not set to 1, so in subflow_syn_recv_sock() will not reset the MP_JOIN subflow, but fallback to normal TCP, and then the same thing happens when server will send a TCP FIN if closed. For case1, subflow_check_req() return -EPERM, then tcp_conn_request() will drop MP_JOIN SYN. For case2, let subflow_syn_recv_sock() call mptcp_can_accept_new_subflow(), and do fatal fallback, send reset. Fixes: 9466a1ccebbe ("mptcp: enable JOIN requests even if cookies are in use") Signed-off-by: Jianguo Wu Signed-off-by: Mat Martineau Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/mptcp/subflow.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 5493c851ca6c..5221cfce5390 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -223,6 +223,8 @@ again: if (unlikely(req->syncookie)) { if (mptcp_can_accept_new_subflow(subflow_req->msk)) subflow_init_req_cookie_join_save(subflow_req, skb); + else + return -EPERM; } pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, @@ -262,9 +264,7 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req, if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) return -EINVAL; - if (mptcp_can_accept_new_subflow(subflow_req->msk)) - subflow_req->mp_join = 1; - + subflow_req->mp_join = 1; subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; } -- 2.30.2