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diff --git a/doc/tls_cert_server.html b/doc/tls_cert_server.html new file mode 100644 index 00000000..51ad7bed --- /dev/null +++ b/doc/tls_cert_server.html @@ -0,0 +1,118 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html><head><title>TLS-protected syslog: central server setup</title> +</head> +<body> + +<h1>Encrypting Syslog Traffic with TLS (SSL)</h1> +<p><small><i>Written by <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer +Gerhards</a> (2008-06-18)</i></small></p> + +<ul> +<li><a href="rsyslog_secure_tls.html">Overview</a> +<li><a href="tls_cert_scenario.html">Sample Scenario</a> +<li><a href="tls_cert_ca.html">Setting up the CA</a> +<li><a href="tls_cert_machine.html">Generating Machine Certificates</a> +<li><a href="tls_cert_server.html">Setting up the Central Server</a> +<li><a href="tls_cert_client.html">Setting up syslog Clients</a> +<li><a href="tls_cert_udp_relay.html">Setting up the UDP syslog relay</a> +<li><a href="tls_cert_summary.html">Wrapping it all up</a> +</ul> + +<h3>Setting up the Central Server</h3> +<p>In this step, we configure the central server. We assume it accepts messages only +via TLS protected plain tcp based syslog from those peers that are explicitely permitted +to send to it. The picture below show our configuration. This step configures +the server central.example.net. +<span style="float: left"> +<script type="text/javascript"><!-- +google_ad_client = "pub-3204610807458280"; +/* rsyslog doc inline */ +google_ad_slot = "5958614527"; +google_ad_width = 125; +google_ad_height = 125; +//--> +</script> +<script type="text/javascript" +src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> +</script> +</span> +<p><center><img src="tls_cert_100.jpg"></center> +<p>Steps to do: +<ul> +<li>make sure you have a functional CA (<a href="tls_cert_ca.html">Setting up the CA</a>) +<li>generate a machine certificate for central.example.net (follow instructions in + <a href="tls_cert_machine.html">Generating Machine Certificates</a>) +<li>make sure you copy over ca.pem, machine-key.pem ad machine-cert.pem to the central server. +Ensure that no user except root can access them (<b>even read permissions are really bad</b>). +<li>configure the server so that it accepts messages from all machines in the +example.net domain that have certificates from your CA. Alternatively, you may also +precisely define from which machine names messages are accepted. See sample rsyslog.conf +below. +</ul> +In this setup, we use wildcards to ease adding new systems. We permit the server to accept +messages from systems whos names match *.example.net. +<pre><code> +$InputTCPServerStreamDriverPermittedPeer *.example.net +</code></pre> +This will match zuse.example.net and +turing.example.net, but NOT pascal.otherdepartment.example.net. If the later would be desired, +you can (and need) to include additional permitted peer config statments: +<pre><code> +$InputTCPServerStreamDriverPermittedPeer *.example.net +$InputTCPServerStreamDriverPermittedPeer *.otherdepartment.example.net +$InputTCPServerStreamDriverPermittedPeer *.example.com +</code></pre> +<p>As can be seen with example.com, the different permitted peers need NOT to be in a single +domain tree. Also, individual machines can be configured. For example, if only zuse, turing +and ada should be able to talk to the server, you can achive this by: +<pre><code> +$InputTCPServerStreamDriverPermittedPeer zuse.example.net +$InputTCPServerStreamDriverPermittedPeer turing.example.net +$InputTCPServerStreamDriverPermittedPeer ada.example.net +</code></pre> +<p>As an extension to the (upcoming) IETF syslog/tls standard, you can specify some text +together with a domain component wildcard. So "*server.example.net", "server*.example.net" +are valid permitted peers. However "server*Fix.example.net" is NOT a valid wildcard. The +IETF standard permits no text along the wildcards. +<p>The reason we use wildcards in the default setup is that it makes it easy to add systems +without the need to change the central server's configuration. It is important to understand that +the central server will accept names <b>only</b> (no exception) if the client certificate was +signed by the CA we set up. So if someone tries to create a malicious certificate with +a name "zuse.example.net", the server will <b>not</b> accept it. So a wildcard is safe +as long as you ensure CA security is not breached. Actually, you authorize a client by issuing +the certificate to it. +<p><b>At this point, please be reminded once again that your security needs may be quite different from +what we assume in this tutorial. Evaluate your options based on your security needs.</b> +<h3>Sample syslog.conf</h3> +<p>Keep in mind that this rsyslog.conf accepts messages via TCP, only. The only other +source accepted is messages from the server itself. +<code><pre> +$ModLoad /home/rger/proj/rsyslog/plugins/imuxsock/.libs/imuxsock # local messages +$ModLoad /home/rger/proj/rsyslog/plugins/imtcp/.libs/imtcp + +# make gtls driver the default +$DefaultNetstreamDriver gtls + +# certificate files +$DefaultNetstreamDriverCAFile /rsyslog/protected/ca.pem +$DefaultNetstreamDriverCertFile /rsyslog/protected/machine-cert.pem +$DefaultNetstreamDriverKeyFile /rsyslog/protected/machine-key.pem + +$InputTCPServerStreamDriverAuthMode x509/name +$InputTCPServerStreamDriverPermittedPeer *.example.net +$InputTCPServerStreamDriverMode 1 # run driver in TLS-only mode +$InputTCPServerRun 10514 # start up listener at port 10514 +</pre></code> +<p><font color="red"><b>Be sure to safeguard at least the private key (machine-key.pem)!</b> +If some third party obtains it, you security is broken!</font> +<h2>Copyright</h2> +<p>Copyright (c) 2008 <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer +Gerhards</a> and +<a href="http://www.adiscon.com/en/">Adiscon</a>.</p> +<p> Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version +1.2 or any later version published by the Free Software Foundation; +with no Invariant Sections, no Front-Cover Texts, and no Back-Cover +Texts. A copy of the license can be viewed at +<a href="http://www.gnu.org/copyleft/fdl.html">http://www.gnu.org/copyleft/fdl.html</a>.</p> +</body></html> |