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<h2><a href="https://wiki.asterisk.org/wiki/display/TOP/Ice+Support+for+SSL">Ice Support for SSL</a></h2>
<h4>Page <b>edited</b> by <a href="https://wiki.asterisk.org/wiki/display/~khunt">Ken Hunt</a>
</h4>
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<h4>Changes (1)</h4>
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<tr><td class="diff-unchanged" ># Asterisk SCF makes heavy use passing proxies between components. <br># A component that cares about secure communications can only insure that locally-created proxies are secure. <br></td></tr>
<tr><td class="diff-changed-lines" >#* Never assume that proxies <span class="diff-deleted-words"style="color:#999;background-color:#fdd;text-decoration:line-through;">passed</span> <span class="diff-added-words"style="background-color: #dfd;">received</span> over the wire are configured to use secure endpoints. <br></td></tr>
<tr><td class="diff-unchanged" >#* The component can call {{SomePrx->ice_secure(true);}} to insure only secure endpoints are used between the component and the remote servant located by {{SomePrx}}. <br>#* Setting this configuration property will result in the component using only secure endpoints for all proxies: <br></td></tr>
<tr><td class="diff-snipped" >...<br></td></tr>
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</div> <h4>Full Content</h4>
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<h4><a name="IceSupportforSSL-Introduction"></a>Introduction</h4>
<p>This page provides information on support for <a href="http://en.wikipedia.org/wiki/Secure_Sockets_Layer" class="external-link" rel="nofollow">Secure Sockets Layer (SSL)</a> in Ice. It is not intended as a replacement for ZeroC's own <a href="http://www.zeroc.com/doc/Ice-3.4.1/manual/IceSSL.html" class="external-link" rel="nofollow">Ice documentation related to SSL</a>, but rather a discussion / overview of relevant points as this functionality pertains to Asterisk SCF.</p>
<h4><a name="IceSupportforSSL-IceSSLPluginandConfiguration"></a>IceSSL Plugin and Configuration</h4>
<ol>
<li>Ice provides support for SSL via the IceSSL plugin. The IceSSL plugin is built on OpenSSL.</li>
<li>Integrating SSL will typically require no changes to source code, but rather to a component's configuration.
<div class="code panel" style="border-width: 1px;"><div class="codeHeader panelHeader" style="border-bottom-width: 1px;"><b>Defining multiple endpoints on an adapter</b></div><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[
MyAdapter.Endpoints=tcp ‑p 4063:ssl ‑p 4064:udp ‑p 4063
]]></script>
</div></div>
<ul>
<li>Note that UDP can use the same port number as TCP or SSL since it's a different protocol with its own set of ports. SSL is a layer over TCP, so SSL and TCP endpoints can't have the same port number.</li>
<li>To provide only secure endpoints for an object adapter: <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[MyAdapter.Endpoints=ssl ‑p 4064]]></script>
</div></div></li>
</ul>
</li>
<li>In addition to changes to an Asterisk SCF component's object adapter configuration, the IceSSL plugin also requires configuration data, which can be placed in the component's configuration file.
<div class="code panel" style="border-width: 1px;"><div class="codeHeader panelHeader" style="border-bottom-width: 1px;"><b>IceSSL plugin configuration parameters</b></div><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[
Ice.Plugin.IceSSL=IceSSL:createIceSSL # Enable IceSSL plugin. This loads the plugin's DLL.
IceSSL.DefaultDir=/opt/certs # Identifies location of certificates
IceSSL.CertFile=pubkey.pem # Identifies filename within the DefaultDir specified above.
IceSSL.KeyFile=privkey.pem # " " "
IceSSL.CertAuthFile=ca.pem # " " "
IceSSL.Password=password # The password of the private key (if key files are encrypted).
# For DSA-generated keys, or using both RSA and DSA, refer to additional configuration parameters in the Ice docs.
# Additional configuration also applies to using Anonymous Diffie-Hellman (ADH) cipher, where no keys are involved. Again, refer to the Ice docs.
]]></script>
</div></div>
<ul>
<li>Storing passwords in a plain-text file (as shown above) is viable only if your server is in a highly secure environment.</li>
<li>Alternatives:
<ol>
<li>Use unsecured key file (again, only in a secure, controlled environment)</li>
<li>Application takes additional responsibility for managing authentication. Examples such as password callbacks and custom certificate verifier plugins <a href="http://www.zeroc.com/doc/Ice-3.4.1/manual/IceSSL.42.6.html" class="external-link" rel="nofollow">described here</a>.</li>
</ol>
</li>
</ul>
</li>
<li>Cyphersuites (particular combinations of encryption, authentication and hashing algorithm) that can be used during handshake negotiation with a peer can be configured. This is useful, for example, if you wanted to eliminate relatively insecure ciphersuites, such as ADH.
<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[
IceSSL.Ciphers=ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH
]]></script>
</div></div>
<ul>
<li>For more information on configuring cyphersuites, read the <a href="http://www.zeroc.com/doc/Ice-3.4.1/manual/IceSSL.42.4.html" class="external-link" rel="nofollow">Ice documentation</a>.</li>
</ul>
</li>
<li>Ice can take additional steps to determine whether a peer should be trusted, beyond what OpenSSL already does.
<ul>
<li>The Ice.TrustOnly properties define a collection of acceptance and rejection filters. For details, read the Ice documents on <a href="http://www.zeroc.com/doc/Ice-3.4.1-IceTouch/manual/PropRef.50.12.html" class="external-link" rel="nofollow">IceSSL Properties</a>.</li>
</ul>
</li>
<li>Components written in C++ and Java can interact directly with the IceSSL plugin.
<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[
class Plugin : public Ice:Plugin
{
plugin:
// ....
virtual void setCertificateVerifier(const CertificateVerifierPtr&) = 0;
virtual void setPasswordPrompt(const PasswordPromptPtr&) = 0;
// ...
]]></script>
</div></div>
<ul>
<li>The <tt>setCertificateVerifier</tt> allows a custom verifier object to be set that gets invoked for each new connection. Ice provides defined classes for obtaining SSL connection information, including providing access to installed certificates, to make writing Certificate Verifiers relatively easy to do. Refer to the <a href="http://www.zeroc.com/doc/Ice-3.4.1/manual/IceSSL.42.5.html" class="external-link" rel="nofollow">Ice documents for more information</a></li>
<li>The <tt>setPasswordPrompt</tt> provides a means for applications (i.e. Asterisk SCF components) to supply the IceSSL plugin with passwords as an alternate to plain-text in configuration files.</li>
</ul>
</li>
</ol>
<h4><a name="IceSupportforSSL-SecurityandProxies"></a>Security and Proxies</h4>
<ol>
<li>Based on the adapter configuration (such as the one shown in the sample code above labeled "Defining multiple endpoints on an adapter"), a proxy may contain a combination of secure and insecure endpoints.</li>
<li>Asterisk SCF makes heavy use passing proxies between components.</li>
<li>A component that cares about secure communications can only insure that locally-created proxies are secure.
<ul>
<li>Never assume that proxies received over the wire are configured to use secure endpoints.</li>
<li>The component can call <tt>SomePrx->ice_secure(true);</tt> to insure only secure endpoints are used between the component and the remote servant located by <tt>SomePrx</tt>.</li>
<li>Setting this configuration property will result in the component using only secure endpoints for all proxies:
<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[Ice.Override.Secure=1]]></script>
</div></div>
<ul>
<li>Attempting to establish a connection on a proxy that doesn't contain a secure endpoint results in <tt>NoEndpointException</tt>.</li>
</ul>
</li>
<li>If you want to allow non-secure endpoints, but give precedence to secure endpoints: <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<script type="syntaxhighlighter" class="toolbar: false; theme: Confluence; brush: java; gutter: false"><![CDATA[ Ice.Default.PreferSecure=1]]></script>
</div></div></li>
</ul>
</li>
</ol>
<h4><a name="IceSupportforSSL-CertificateAuthority"></a>Certificate Authority </h4>
<ul>
<li>Ice provides the Python script <b>iceca</b> to hide the complexities of using the underlying OpenSSL to setup your own certificate authority (CA) to create new certificates.</li>
<li>Using the CA capabilities of OpenSSL, you can create and sign your own certificates for testing.</li>
</ul>
</div>
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