From patchwork Wed Jan 31 22:59:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 13540159 X-Patchwork-Delegate: kuba@kernel.org Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7C5D63A8F2; Wed, 31 Jan 2024 22:59:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.188.207 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706741998; cv=none; b=DOpLac/1rrJxO8Wpi4fE6Pm30P3ZrhpGqX+RerSSk9riT/65SdtirAne3MQIV3m3xTdKdoICJSy/iI49vEq6Cx0rIQZoPyQNzcCowVBBXW6yX1Zq0fm59MxBFpnvqN5q43lpoxQU2sKvz35nMhdjl+KDoKWtqpmQaiDZfSIxJ/o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706741998; c=relaxed/simple; bh=KRbE94J7PW/QGaCiE+LqGSyY7SxwARqpTXu83e6Susg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=JZD4IeBSp3ZNOQPRK8INRNB6N7bUOwJUZ3yArP18iNgGVUVoGiB1wB7Vz1w/JUBOn5Wp/jKJjF8ce6jH3tP8j5kzeK8SbmmeTlxN3Mv/dNOHqss8HSIOGNG2qlkvx5yrEo9KQizrVkmo7r6hsZuo9lP9xuEc3jgJ05aWgtzwARw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; arc=none smtp.client-ip=217.70.188.207 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, fw@strlen.de Subject: [PATCH net 3/6] netfilter: conntrack: check SCTP_CID_SHUTDOWN_ACK for vtag setting in sctp_new Date: Wed, 31 Jan 2024 23:59:40 +0100 Message-Id: <20240131225943.7536-4-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240131225943.7536-1-pablo@netfilter.org> References: <20240131225943.7536-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Xin Long The annotation says in sctp_new(): "If it is a shutdown ack OOTB packet, we expect a return shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8)". However, it does not check SCTP_CID_SHUTDOWN_ACK before setting vtag[REPLY] in the conntrack entry(ct). Because of that, if the ct in Router disappears for some reason in [1] with the packet sequence like below: Client > Server: sctp (1) [INIT] [init tag: 3201533963] Server > Client: sctp (1) [INIT ACK] [init tag: 972498433] Client > Server: sctp (1) [COOKIE ECHO] Server > Client: sctp (1) [COOKIE ACK] Client > Server: sctp (1) [DATA] (B)(E) [TSN: 3075057809] Server > Client: sctp (1) [SACK] [cum ack 3075057809] Server > Client: sctp (1) [HB REQ] (the ct in Router disappears somehow) <-------- [1] Client > Server: sctp (1) [HB ACK] Client > Server: sctp (1) [DATA] (B)(E) [TSN: 3075057810] Client > Server: sctp (1) [DATA] (B)(E) [TSN: 3075057810] Client > Server: sctp (1) [HB REQ] Client > Server: sctp (1) [DATA] (B)(E) [TSN: 3075057810] Client > Server: sctp (1) [HB REQ] Client > Server: sctp (1) [ABORT] when processing HB ACK packet in Router it calls sctp_new() to initialize the new ct with vtag[REPLY] set to HB_ACK packet's vtag. Later when sending DATA from Client, all the SACKs from Server will get dropped in Router, as the SACK packet's vtag does not match vtag[REPLY] in the ct. The worst thing is the vtag in this ct will never get fixed by the upcoming packets from Server. This patch fixes it by checking SCTP_CID_SHUTDOWN_ACK before setting vtag[REPLY] in the ct in sctp_new() as the annotation says. With this fix, it will leave vtag[REPLY] in ct to 0 in the case above, and the next HB REQ/ACK from Server is able to fix the vtag as its value is 0 in nf_conntrack_sctp_packet(). Signed-off-by: Xin Long Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_proto_sctp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c index c6bd533983c1..4cc97f971264 100644 --- a/net/netfilter/nf_conntrack_proto_sctp.c +++ b/net/netfilter/nf_conntrack_proto_sctp.c @@ -283,7 +283,7 @@ sctp_new(struct nf_conn *ct, const struct sk_buff *skb, pr_debug("Setting vtag %x for secondary conntrack\n", sh->vtag); ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag; - } else { + } else if (sch->type == SCTP_CID_SHUTDOWN_ACK) { /* If it is a shutdown ack OOTB packet, we expect a return shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */ pr_debug("Setting vtag %x for new conn OOTB\n",