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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, 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 A2EFBC43463 for ; Fri, 18 Sep 2020 03:10:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64C0E206DB for ; Fri, 18 Sep 2020 03:10:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600398618; bh=0x3+CDD+td9StTCEH6pNHswN9oNQ0to/bCujROd3J54=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VO8kIjM/VOHRSS34wObE8DVZ7WnJcSwiVoeP3kjM/o8n8zuGtb9feYmoZi6Hs79Tu Glngg2ztnOUCSZoviARZf6+yOf77sgcipvLO5Wy9qha51TzHY8/F/9EQx+kyZmmuyW BOUuwre5N9q+tlmoyKi0XRWiI4pZhraToA0s8y/w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728578AbgIRDKR (ORCPT ); Thu, 17 Sep 2020 23:10:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:48430 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726855AbgIRCCv (ORCPT ); Thu, 17 Sep 2020 22:02:51 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2B3CD235F7; Fri, 18 Sep 2020 02:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394566; bh=0x3+CDD+td9StTCEH6pNHswN9oNQ0to/bCujROd3J54=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DgmJnpU+o+5ChCfDRIPMYSA99M67TPWCPm9CfCLHqL9FEcFEtoa0eXHxmXMZdQFhv M3NWFMFThDRcw7f6verTMFM6mB+Xf2RrcGHxUZU38H45ht6BWeCWiizKV2DveTz9HY DRD3QfswMnFE8tdoNMfRIZjnYmuwVO9wr2aoe3eU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tuong Lien , Ying Xue , Jon Maloy , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net Subject: [PATCH AUTOSEL 5.4 078/330] tipc: fix link overflow issue at socket shutdown Date: Thu, 17 Sep 2020 21:56:58 -0400 Message-Id: <20200918020110.2063155-78-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020110.2063155-1-sashal@kernel.org> References: <20200918020110.2063155-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tuong Lien [ Upstream commit 49afb806cb650dd1f06f191994f3aa657d264009 ] When a socket is suddenly shutdown or released, it will reject all the unreceived messages in its receive queue. This applies to a connected socket too, whereas there is only one 'FIN' message required to be sent back to its peer in this case. In case there are many messages in the queue and/or some connections with such messages are shutdown at the same time, the link layer will easily get overflowed at the 'TIPC_SYSTEM_IMPORTANCE' backlog level because of the message rejections. As a result, the link will be taken down. Moreover, immediately when the link is re-established, the socket layer can continue to reject the messages and the same issue happens... The commit refactors the '__tipc_shutdown()' function to only send one 'FIN' in the situation mentioned above. For the connectionless case, it is unavoidable but usually there is no rejections for such socket messages because they are 'dest-droppable' by default. In addition, the new code makes the other socket states clear (e.g.'TIPC_LISTEN') and treats as a separate case to avoid misbehaving. Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/tipc/socket.c | 53 ++++++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 21 deletions(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 5318bb6611abc..592c6b19aca72 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -260,12 +260,12 @@ static void tipc_sk_respond(struct sock *sk, struct sk_buff *skb, int err) * * Caller must hold socket lock */ -static void tsk_rej_rx_queue(struct sock *sk) +static void tsk_rej_rx_queue(struct sock *sk, int error) { struct sk_buff *skb; while ((skb = __skb_dequeue(&sk->sk_receive_queue))) - tipc_sk_respond(sk, skb, TIPC_ERR_NO_PORT); + tipc_sk_respond(sk, skb, error); } static bool tipc_sk_connected(struct sock *sk) @@ -515,34 +515,45 @@ static void __tipc_shutdown(struct socket *sock, int error) /* Remove any pending SYN message */ __skb_queue_purge(&sk->sk_write_queue); - /* Reject all unreceived messages, except on an active connection - * (which disconnects locally & sends a 'FIN+' to peer). - */ - while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { - if (TIPC_SKB_CB(skb)->bytes_read) { - kfree_skb(skb); - continue; - } - if (!tipc_sk_type_connectionless(sk) && - sk->sk_state != TIPC_DISCONNECTING) { - tipc_set_sk_state(sk, TIPC_DISCONNECTING); - tipc_node_remove_conn(net, dnode, tsk->portid); - } - tipc_sk_respond(sk, skb, error); + /* Remove partially received buffer if any */ + skb = skb_peek(&sk->sk_receive_queue); + if (skb && TIPC_SKB_CB(skb)->bytes_read) { + __skb_unlink(skb, &sk->sk_receive_queue); + kfree_skb(skb); } - if (tipc_sk_type_connectionless(sk)) + /* Reject all unreceived messages if connectionless */ + if (tipc_sk_type_connectionless(sk)) { + tsk_rej_rx_queue(sk, error); return; + } - if (sk->sk_state != TIPC_DISCONNECTING) { + switch (sk->sk_state) { + case TIPC_CONNECTING: + case TIPC_ESTABLISHED: + tipc_set_sk_state(sk, TIPC_DISCONNECTING); + tipc_node_remove_conn(net, dnode, tsk->portid); + /* Send a FIN+/- to its peer */ + skb = __skb_dequeue(&sk->sk_receive_queue); + if (skb) { + __skb_queue_purge(&sk->sk_receive_queue); + tipc_sk_respond(sk, skb, error); + break; + } skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG, SHORT_H_SIZE, 0, dnode, tsk_own_node(tsk), tsk_peer_port(tsk), tsk->portid, error); if (skb) tipc_node_xmit_skb(net, skb, dnode, tsk->portid); - tipc_node_remove_conn(net, dnode, tsk->portid); - tipc_set_sk_state(sk, TIPC_DISCONNECTING); + break; + case TIPC_LISTEN: + /* Reject all SYN messages */ + tsk_rej_rx_queue(sk, error); + break; + default: + __skb_queue_purge(&sk->sk_receive_queue); + break; } } @@ -2564,7 +2575,7 @@ static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags, * Reject any stray messages received by new socket * before the socket lock was taken (very, very unlikely) */ - tsk_rej_rx_queue(new_sk); + tsk_rej_rx_queue(new_sk, TIPC_ERR_NO_PORT); /* Connect new socket to it's peer */ tipc_sk_finish_conn(new_tsock, msg_origport(msg), msg_orignode(msg)); -- 2.25.1