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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 2766FC33CAF for ; Thu, 16 Jan 2020 19:01:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03EAC206D7 for ; Thu, 16 Jan 2020 19:01:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579201312; bh=CG0j5CIjKNoT9C0veCZho73jXHeOkr6pOUdwpcE3xic=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eUj6TTMwPQ/rJQFppkpbwCqUSFw7OQhwSIv3YZFkiMcIkerTvKh79u8GRxbAsE4Z8 QqZDgcbYiaQyeRKOGS7ku+1pZ7x2EHTAWxmngpwG3Y9rL1oAgQzPfi0hfifX6f03Z2 h3pjBG9y7giiWYAgSJ7HE9gyzFCXO0wGTDrYltNw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437299AbgAPTBu (ORCPT ); Thu, 16 Jan 2020 14:01:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:35110 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388733AbgAPRFs (ORCPT ); Thu, 16 Jan 2020 12:05:48 -0500 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 1D6AD20730; Thu, 16 Jan 2020 17:05:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194347; bh=CG0j5CIjKNoT9C0veCZho73jXHeOkr6pOUdwpcE3xic=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PS4as2vySiimtkRm/RTXAH7MkR5Ndw7Ff7NhMObimaa22ALkrF+CY4hyNz/3yvWtc xJoiXJ1IVI2iG2Y6C4cVTzBlgmoQ0+HdHq1ZfBK5ijFok6SiY1MToAwd2syM2jOb1k fCdyd1X/UDRnM+NSb2rQ/WtB2sCfuedIix0drRBQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jeffrey Altman , David Howells , Marc Dionne , "David S . Miller" , Sasha Levin , linux-afs@lists.infradead.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 288/671] rxrpc: Fix detection of out of order acks Date: Thu, 16 Jan 2020 11:58:46 -0500 Message-Id: <20200116170509.12787-25-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116170509.12787-1-sashal@kernel.org> References: <20200116170509.12787-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeffrey Altman [ Upstream commit 1a2391c30c0b9d041bc340f68df81d49c53546cc ] The rxrpc packet serial number cannot be safely used to compute out of order ack packets for several reasons: 1. The allocation of serial numbers cannot be assumed to imply the order by which acks are populated and transmitted. In some rxrpc implementations, delayed acks and ping acks are transmitted asynchronously to the receipt of data packets and so may be transmitted out of order. As a result, they can race with idle acks. 2. Serial numbers are allocated by the rxrpc connection and not the call and as such may wrap independently if multiple channels are in use. In any case, what matters is whether the ack packet provides new information relating to the bounds of the window (the firstPacket and previousPacket in the ACK data). Fix this by discarding packets that appear to wind back the window bounds rather than on serial number procession. Fixes: 298bc15b2079 ("rxrpc: Only take the rwind and mtu values from latest ACK") Signed-off-by: Jeffrey Altman Signed-off-by: David Howells Tested-by: Marc Dionne Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/rxrpc/ar-internal.h | 1 + net/rxrpc/input.c | 18 ++++++++++++------ 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index dfd9eab77cc8..37e4c1801a41 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -644,6 +644,7 @@ struct rxrpc_call { u8 ackr_reason; /* reason to ACK */ u16 ackr_skew; /* skew on packet being ACK'd */ rxrpc_serial_t ackr_serial; /* serial of packet being ACK'd */ + rxrpc_serial_t ackr_first_seq; /* first sequence number received */ rxrpc_seq_t ackr_prev_seq; /* previous sequence number received */ rxrpc_seq_t ackr_consumed; /* Highest packet shown consumed */ rxrpc_seq_t ackr_seen; /* Highest packet shown seen */ diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index 7965600ee5de..2f91ab909191 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -837,7 +837,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, u8 acks[RXRPC_MAXACKS]; } buf; rxrpc_serial_t acked_serial; - rxrpc_seq_t first_soft_ack, hard_ack; + rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt; int nr_acks, offset, ioffset; _enter(""); @@ -851,13 +851,14 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, acked_serial = ntohl(buf.ack.serial); first_soft_ack = ntohl(buf.ack.firstPacket); + prev_pkt = ntohl(buf.ack.previousPacket); hard_ack = first_soft_ack - 1; nr_acks = buf.ack.nAcks; summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ? buf.ack.reason : RXRPC_ACK__INVALID); trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial, - first_soft_ack, ntohl(buf.ack.previousPacket), + first_soft_ack, prev_pkt, summary.ack_reason, nr_acks); if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE) @@ -878,8 +879,9 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, rxrpc_propose_ack_respond_to_ack); } - /* Discard any out-of-order or duplicate ACKs. */ - if (before_eq(sp->hdr.serial, call->acks_latest)) + /* Discard any out-of-order or duplicate ACKs (outside lock). */ + if (before(first_soft_ack, call->ackr_first_seq) || + before(prev_pkt, call->ackr_prev_seq)) return; buf.info.rxMTU = 0; @@ -890,12 +892,16 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, spin_lock(&call->input_lock); - /* Discard any out-of-order or duplicate ACKs. */ - if (before_eq(sp->hdr.serial, call->acks_latest)) + /* Discard any out-of-order or duplicate ACKs (inside lock). */ + if (before(first_soft_ack, call->ackr_first_seq) || + before(prev_pkt, call->ackr_prev_seq)) goto out; call->acks_latest_ts = skb->tstamp; call->acks_latest = sp->hdr.serial; + call->ackr_first_seq = first_soft_ack; + call->ackr_prev_seq = prev_pkt; + /* Parse rwind and mtu sizes if provided. */ if (buf.info.rxMTU) rxrpc_input_ackinfo(call, skb, &buf.info); -- 2.20.1