From patchwork Thu Jan 28 13:07:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Davide Caratti X-Patchwork-Id: 1432790 X-Patchwork-Delegate: matthieu.baerts@tessares.net Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.01.org (client-ip=2001:19d0:306:5::1; helo=ml01.01.org; envelope-from=mptcp-bounces@lists.01.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=TZeiN2vV; dkim-atps=neutral Received: from ml01.01.org (ml01.01.org [IPv6:2001:19d0:306:5::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4DRLPL345sz9sSC for ; Fri, 29 Jan 2021 00:08:05 +1100 (AEDT) Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 5EDAA100EB846; Thu, 28 Jan 2021 05:08:01 -0800 (PST) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=63.128.21.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=dcaratti@redhat.com; receiver= Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id D3DBB100EC1EC for ; Thu, 28 Jan 2021 05:07:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611839277; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=7lH1JA0LMANjXudCBdujKPxThZY64NjVgVwrd6zabnU=; b=TZeiN2vV5ZNenxr/Tex7C50iIVEEg0Rb/3LymN379P3Kqzj0HGtRmtlzcXbeFyalgYO8XW ICFb25JX3BP5g+52yJhKoYIKvO7Ft5mTTynBX3GJuLG2QniSh0OZZJmsD/+aRZznbM3I10 EvGwLRqJb/v9o+hvu57KnyZxwNsN3XY= 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-506-4muNZgcIOEeBg7iynjnuKA-1; Thu, 28 Jan 2021 08:07:55 -0500 X-MC-Unique: 4muNZgcIOEeBg7iynjnuKA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7EFAB911E4; Thu, 28 Jan 2021 13:07:54 +0000 (UTC) Received: from computer-6.station (unknown [10.40.195.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3CCE75D720; Thu, 28 Jan 2021 13:07:53 +0000 (UTC) From: Davide Caratti To: Geliang Tang , mptcp@lists.01.org, Matthieu Baerts Date: Thu, 28 Jan 2021 14:07:39 +0100 Message-Id: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dcaratti@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Message-ID-Hash: FOQ5TUOJQPDN7IY2VANQQAXXMV2PUZX7 X-Message-ID-Hash: FOQ5TUOJQPDN7IY2VANQQAXXMV2PUZX7 X-MailFrom: dcaratti@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header X-Mailman-Version: 3.1.1 Precedence: list Subject: [MPTCP] [PATCH net-next v2] net: mptcp: fix length of MP_PRIO sub-option List-Id: Discussions regarding MPTCP upstreaming Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: With version 0 of the protocol it was legal to encode the 'Subflow Id' in the MP_PRIO suboption, to specify which subflow would change its 'Backup' flag. This has been removed from v1 specification: thus, according to RFC 8684 ยง3.3.8, the resulting 'Length' for MP_PRIO changed from 4 to 3 byte. Current Linux generates / parses MP_PRIO according to the old spec, using 'Length' equal to 4, and hardcoding 1 as 'Subflow Id'; RFC compliance can improve if we change 'Length' in other to become 3, leaving a 'Nop' after the MP_PRIO suboption. In this way the kernel will emit and accept *only* MP_PRIO suboptions that are compliant to version 1 of the MPTCP protocol. unpatched 5.11-rc kernel: [root@bottarga ~]# tcpdump -tnnr unpatched.pcap | grep prio reading from file unpatched.pcap, link-type LINUX_SLL (Linux cooked v1) dropped privs to tcpdump IP 10.0.3.2.48433 > 10.0.1.1.10006: Flags [.], ack 1, win 502, options [nop,nop,TS val 4032325513 ecr 1876514270,mptcp prio non-backup id 1,mptcp dss ack 14084896651682217737], length 0 patched 5.11-rc kernel: [root@bottarga ~]# tcpdump -tnnr patched.pcap | grep prio reading from file patched.pcap, link-type LINUX_SLL (Linux cooked v1) dropped privs to tcpdump IP 10.0.3.2.49735 > 10.0.1.1.10006: Flags [.], ack 1, win 502, options [nop,nop,TS val 1276737699 ecr 2686399734,mptcp prio non-backup,nop,mptcp dss ack 18433038869082491686], length 0 Changes since v1: - refactor patch to avoid using 'TCPOLEN_MPTCP_PRIO' with its old value, thanks to Geliang Tang. Fixes: 067065422fcd ("mptcp: add the outgoing MP_PRIO support") Signed-off-by: Davide Caratti --- net/mptcp/options.c | 5 +++-- net/mptcp/protocol.h | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 775f0576592e..6e088c583992 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -699,10 +699,11 @@ static bool mptcp_established_options_mp_prio(struct sock *sk, if (!subflow->send_mp_prio) return false; - if (remaining < TCPOLEN_MPTCP_PRIO) + /* account for the trailing 'nop' option */ + if (remaining < TCPOLEN_MPTCP_PRIO + 1) return false; - *size = TCPOLEN_MPTCP_PRIO; + *size = TCPOLEN_MPTCP_PRIO + 1; opts->suboptions |= OPTION_MPTCP_PRIO; opts->backup = subflow->request_bkup; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 447ce4631b43..c61f5731eccd 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -61,7 +61,7 @@ #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT 24 #define TCPOLEN_MPTCP_PORT_LEN 4 #define TCPOLEN_MPTCP_RM_ADDR_BASE 4 -#define TCPOLEN_MPTCP_PRIO 4 +#define TCPOLEN_MPTCP_PRIO 3 #define TCPOLEN_MPTCP_FASTCLOSE 12 /* MPTCP MP_JOIN flags */