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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 36782FC6195 for ; Fri, 8 Nov 2019 19:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CE6B20656 for ; Fri, 8 Nov 2019 19:21:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573240916; bh=XrldGzU/vehg9sYXQT4wwRSAys/T6+j97R70Fz5Jux4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CvIcOzpmnfMO9CsDaiqPgVzD/Z6DRE9d72QeS6iO0oYVXGY/V59094QqaUmBw4AZh PCeHxPuIhFx4k+HuJvSKmIx+bvM0THUw1kIDUZ0MNmYNSQiNneoYOaOcHYQRCd1SyF LHSPrNffp2De6qALzNcUeX5qrKquyEGDh2V2ZOqY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388537AbfKHS45 (ORCPT ); Fri, 8 Nov 2019 13:56:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:54472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388399AbfKHS4r (ORCPT ); Fri, 8 Nov 2019 13:56:47 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D5B412067B; Fri, 8 Nov 2019 18:56:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573239406; bh=XrldGzU/vehg9sYXQT4wwRSAys/T6+j97R70Fz5Jux4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v2aEUaOdi95wJsfN5a0AzYmoxXWZ9EOIWE9nmnYK0TMkQrZvv8vK0q2/XgQ2Q+oNV Zv8GlKuC550CrviBKqh67RzlrDkfov0DnlVsIMIXndli/nctvzVmRgd1k/8HGN/jYZ 0JMa2/yNfGD0iCxH6NmRbB3hDTFV/LVs+W1f6HRw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Thiemo Nagel , "David S. Miller" Subject: [PATCH 4.9 28/34] inet: stop leaking jiffies on the wire Date: Fri, 8 Nov 2019 19:50:35 +0100 Message-Id: <20191108174651.026609810@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191108174618.266472504@linuxfoundation.org> References: <20191108174618.266472504@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet [ Upstream commit a904a0693c189691eeee64f6c6b188bd7dc244e9 ] Historically linux tried to stick to RFC 791, 1122, 2003 for IPv4 ID field generation. RFC 6864 made clear that no matter how hard we try, we can not ensure unicity of IP ID within maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. Linux uses a per socket inet generator (inet_id), initialized at connection startup with a XOR of 'jiffies' and other fields that appear clear on the wire. Thiemo Nagel pointed that this strategy is a privacy concern as this provides 16 bits of entropy to fingerprint devices. Let's switch to a random starting point, this is just as good as far as RFC 6864 is concerned and does not leak anything critical. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: Thiemo Nagel Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/dccp/ipv4.c | 2 +- net/ipv4/datagram.c | 2 +- net/ipv4/tcp_ipv4.c | 4 ++-- net/sctp/socket.c | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -121,7 +121,7 @@ int dccp_v4_connect(struct sock *sk, str inet->inet_daddr, inet->inet_sport, inet->inet_dport); - inet->inet_id = dp->dccps_iss ^ jiffies; + inet->inet_id = prandom_u32(); err = dccp_connect(sk); rt = NULL; --- a/net/ipv4/datagram.c +++ b/net/ipv4/datagram.c @@ -75,7 +75,7 @@ int __ip4_datagram_connect(struct sock * inet->inet_dport = usin->sin_port; sk->sk_state = TCP_ESTABLISHED; sk_set_txhash(sk); - inet->inet_id = jiffies; + inet->inet_id = prandom_u32(); sk_dst_set(sk, &rt->dst); err = 0; --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -239,7 +239,7 @@ int tcp_v4_connect(struct sock *sk, stru inet->inet_sport, usin->sin_port); - inet->inet_id = tp->write_seq ^ jiffies; + inet->inet_id = prandom_u32(); err = tcp_connect(sk); @@ -1307,7 +1307,7 @@ struct sock *tcp_v4_syn_recv_sock(const inet_csk(newsk)->icsk_ext_hdr_len = 0; if (inet_opt) inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; - newinet->inet_id = newtp->write_seq ^ jiffies; + newinet->inet_id = prandom_u32(); if (!dst) { dst = inet_csk_route_child_sock(sk, newsk, req); --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -7734,7 +7734,7 @@ void sctp_copy_sock(struct sock *newsk, newinet->inet_rcv_saddr = inet->inet_rcv_saddr; newinet->inet_dport = htons(asoc->peer.port); newinet->pmtudisc = inet->pmtudisc; - newinet->inet_id = asoc->next_tsn ^ jiffies; + newinet->inet_id = prandom_u32(); newinet->uc_ttl = inet->uc_ttl; newinet->mc_loop = 1;