<!DOCTYPE html> <!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]--> <!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]--> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Plugin Programmer’s Guide — Cyrus SASL 2.1.27 documentation</title> <link rel="shortcut icon" href="../../_static/favicon.ico"/> <link rel="stylesheet" href="../../_static/css/theme.css" type="text/css" /> <link rel="stylesheet" href="../../_static/cyrus.css" type="text/css" /> <link rel="index" title="Index" href="../../genindex.html"/> <link rel="search" title="Search" href="../../search.html"/> <link rel="top" title="Cyrus SASL 2.1.27 documentation" href="../../index.html"/> <link rel="up" title="Developers" href="../../developer.html"/> <link rel="next" title="Testing" href="testing.html"/> <link rel="prev" title="Application Programmer’s Guide" href="programming.html"/> </head> <body class="wy-body-for-nav" role="document"> <div class="pageheader"> <ul> <li><a href="../../index.html">Home</a></li> <li><a href="http://www.cyrusimap.org">Cyrus IMAP</a></li> <li><a href="../../download.html">Download</a></li> <li><a href="../../contribute.html">Contribute</a></li> </ul> <div> <a href="../../index.html"> <img src="../../_static/logo.gif" alt="CYRUS SASL" /> </a> </div> </div> <div style="clear: both;"></div> <div class="wy-grid-for-nav"> <nav data-toggle="wy-nav-shift" class="wy-nav-side"> <div class="wy-side-nav-search"> <a href="../../index.html"> <img src="../../_static/logo.gif" /> </a> <div role="search"> <form id="rtd-search-form" class="wy-form" action="../../search.html" method="get"> <input type="text" name="q" placeholder="Search docs" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> </div> <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation"> <p class="caption"><span class="caption-text">Cyrus SASL</span></p> <ul class="current"> <li class="toctree-l1"><a class="reference internal" href="../../download.html">Download</a><ul> <li class="toctree-l2"><a class="reference internal" href="../../getsasl.html">Get SASL</a><ul> <li class="toctree-l3"><a class="reference internal" href="../installation.html">Installation</a><ul> <li class="toctree-l4"><a class="reference internal" href="../installation.html#quick-install-guide">Quick install guide</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#detailed-installation-guide">Detailed installation guide</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#supported-platforms">Supported platforms</a></li> </ul> </li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../release-notes/index.html">Release Notes</a><ul> <li class="toctree-l3"><a class="reference internal" href="../release-notes/index.html#supported-product-series">Supported Product Series</a><ul> <li class="toctree-l4"><a class="reference internal" href="../release-notes/index.html#series-2-1">Series 2.1</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../release-notes/index.html#older-versions">Older Versions</a><ul> <li class="toctree-l4"><a class="reference internal" href="../release-notes/index.html#series-2-2-0">Series 2: 2.0</a></li> <li class="toctree-l4"><a class="reference internal" href="../release-notes/index.html#series-1">Series 1</a></li> </ul> </li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../../packager.html">Note for Packagers</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="../quickstart.html">Quickstart guide</a><ul> <li class="toctree-l2"><a class="reference internal" href="../quickstart.html#features">Features</a></li> <li class="toctree-l2"><a class="reference internal" href="../quickstart.html#typical-installation">Typical Installation</a></li> <li class="toctree-l2"><a class="reference internal" href="../quickstart.html#configuration">Configuration</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="../concepts.html">Concepts</a><ul> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#sasl">SASL</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#sasl-authentication-mechanisms">SASL Authentication Mechanisms</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#security-layers">Security Layers</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#channel-binding">Channel Binding</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#realms">Realms</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#protocols">Protocols</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#cyrus-sasl">Cyrus SASL</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#the-glue-library">The Glue Library</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#auxiliary-properties">Auxiliary Properties</a></li> <li class="toctree-l2"><a class="reference internal" href="../concepts.html#plugins">Plugins</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="../../setup.html">Setup</a><ul> <li class="toctree-l2"><a class="reference internal" href="../installation.html">Installation</a><ul> <li class="toctree-l3"><a class="reference internal" href="../installation.html#quick-install-guide">Quick install guide</a><ul> <li class="toctree-l4"><a class="reference internal" href="../installation.html#tarball-installation">Tarball installation</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#unix-package-installation">Unix package Installation</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#configuration">Configuration</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../installation.html#detailed-installation-guide">Detailed installation guide</a><ul> <li class="toctree-l4"><a class="reference internal" href="../installation.html#requirements">Requirements</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#build-configuration">Build Configuration</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#building-and-installation">Building and Installation</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#compilation-hints">Compilation Hints</a></li> <li class="toctree-l4"><a class="reference internal" href="../installation.html#application-configuration">Application Configuration</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../installation.html#supported-platforms">Supported platforms</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../upgrading.html">Upgrading from v1 to v2</a><ul> <li class="toctree-l3"><a class="reference internal" href="../upgrading.html#backwards-compatibility">Backwards Compatibility</a></li> <li class="toctree-l3"><a class="reference internal" href="../upgrading.html#coexistence-with-saslv1">Coexistence with SASLv1</a></li> <li class="toctree-l3"><a class="reference internal" href="../upgrading.html#database-upgrades">Database Upgrades</a></li> <li class="toctree-l3"><a class="reference internal" href="../upgrading.html#errors-on-migration">Errors on migration</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../components.html">Components</a><ul> <li class="toctree-l3"><a class="reference internal" href="../components.html#the-application">The Application</a></li> <li class="toctree-l3"><a class="reference internal" href="../components.html#the-sasl-glue-layer">The SASL Glue Layer</a></li> <li class="toctree-l3"><a class="reference internal" href="../components.html#plugins">Plugins</a><ul> <li class="toctree-l4"><a class="reference internal" href="../components.html#plugins-general">Plugins: General</a></li> <li class="toctree-l4"><a class="reference internal" href="../components.html#plugins-sasl-mechanisms">Plugins: SASL Mechanisms</a></li> <li class="toctree-l4"><a class="reference internal" href="../components.html#plugins-auxiliary-property">Plugins: Auxiliary Property</a></li> <li class="toctree-l4"><a class="reference internal" href="../components.html#plugins-username-canonicalization">Plugins: Username Canonicalization</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../components.html#password-verification-services">Password Verification Services</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../options.html">Options</a><ul> <li class="toctree-l3"><a class="reference internal" href="../options.html#sasl-library">SASL Library</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#auxiliary-property-plugin">Auxiliary Property Plugin</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#gssapi">GSSAPI</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#ldapdb">LDAPDB</a><ul> <li class="toctree-l4"><a class="reference internal" href="../options.html#notes-on-ldapdb">Notes on LDAPDB</a></li> <li class="toctree-l4"><a class="reference internal" href="../options.html#examples">Examples</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../options.html#ntlm">NTLM</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#otp">OTP</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#digest-md5">Digest-md5</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#sasldb">SASLDB</a><ul> <li class="toctree-l4"><a class="reference internal" href="../options.html#notes-on-sasldb-with-lmdb">Notes on sasldb with LMDB</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../options.html#sql-plugin">SQL Plugin</a><ul> <li class="toctree-l4"><a class="reference internal" href="../options.html#notes-on-sql">Notes on SQL</a></li> <li class="toctree-l4"><a class="reference internal" href="../options.html#id2">Examples</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../options.html#srp">SRP</a></li> <li class="toctree-l3"><a class="reference internal" href="../options.html#kerberos-v4">Kerberos V4</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../advanced.html">Advanced Usage</a><ul> <li class="toctree-l3"><a class="reference internal" href="../advanced.html#notes-for-advanced-usage-of-libsasl">Notes for Advanced Usage of libsasl</a><ul> <li class="toctree-l4"><a class="reference internal" href="../advanced.html#using-cyrus-sasl-as-a-static-library">Using Cyrus SASL as a static library</a></li> </ul> </li> </ul> </li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="../../operations.html">Operations</a><ul> <li class="toctree-l2"><a class="reference internal" href="../sysadmin.html">System Administrators</a><ul> <li class="toctree-l3"><a class="reference internal" href="../sysadmin.html#what-sasl-is">What SASL is</a><ul> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#authentication-and-authorization-identifiers">Authentication and authorization identifiers</a></li> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#realms">Realms</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../sysadmin.html#how-sasl-works">How SASL works</a><ul> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#the-plain-mechanism-sasl-checkpass-and-plaintext-passwords">The PLAIN mechanism, <code class="docutils literal"><span class="pre">sasl_checkpass()</span></code>, and plaintext passwords</a></li> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#shared-secrets-mechanisms">Shared secrets mechanisms</a></li> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#kerberos-mechanisms">Kerberos mechanisms</a></li> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#the-otp-mechanism">The OTP mechanism</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../sysadmin.html#auxiliary-properties">Auxiliary Properties</a></li> <li class="toctree-l3"><a class="reference internal" href="../sysadmin.html#how-to-set-configuration-options">How to set configuration options</a><ul> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#the-default-configuration-file">The default configuration file</a></li> <li class="toctree-l4"><a class="reference internal" href="../sysadmin.html#application-configuration">Application configuration</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../sysadmin.html#troubleshooting">Troubleshooting</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../manpages.html">Man pages</a><ul> <li class="toctree-l3"><a class="reference internal" href="../manpages.html#library-files">(3) Library Files</a><ul> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl.html"><strong>SASL</strong> - SASL Authentication Library</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_authorize_t.html"><strong>sasl_authorize_t</strong> - The SASL authorization callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_auxprop.html"><strong>sasl_auxprop</strong> - How to work with SASL auxiliary properties</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_auxprop_add_plugin.html"><strong>sasl_auxprop_add_plugin</strong> - add a SASL auxiliary property plugin</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_auxprop_getctx.html"><strong>sasl_auxprop_getctx</strong> - Acquire an auxiliary property context</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_auxprop_request.html"><strong>sasl_auxprop_request</strong> - Request auxiliary properties from SASL</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_callbacks.html"><strong>sasl_callbacks</strong> - How to work with SASL callbacks</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_canon_user_t.html"><strong>sasl_canon_user_t</strong> - Application-supplied user canonicalization function</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_canonuser_add_plugin.html"><strong>sasl_canonuser_add_plugin</strong> - add a SASL user canonicalization plugin</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_chalprompt_t.html"><strong>sasl_chalprompt_t</strong> - Realm acquisition callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_checkapop.html"><strong>sasl_checkapop</strong> - Check an APOP challenge/response</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_checkpass.html"><strong>sasl_checkpass</strong> - Check a plaintext password</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_add_plugin.html"><strong>sasl_client_add_plugin</strong> - add a SASL client plugin</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_done.html"><strong>sasl_client_done</strong> - Cleanup function</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_init.html"><strong>sasl_client_init</strong> - SASL client authentication initialization</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_new.html"><strong>sasl_client_new</strong> - Create a new client authentication object</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_plug_init_t.html"><strong>sasl_client_plug_init_t</strong> - client plug‐in entry point</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_start.html"><strong>sasl_client_start</strong> - Begin an authentication negotiation</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_client_step.html"><strong>sasl_client_step</strong> - Perform a step in the authentication negotiation</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_decode.html"><strong>sasl_decode</strong> - Decode data received</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_decode64.html"><strong>sasl_decode64</strong> - Decode base64 string</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_dispose.html"><strong>sasl_dispose</strong> - Dispose of a SASL connection object</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_done.html"><strong>sasl_done</strong> - Dispose of a SASL connection object</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_encode.html"><strong>sasl_encode</strong> - Encode data for transport to authenticated host</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_encode64.html"><strong>sasl_encode64</strong> - Encode base64 string</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_encodev.html"><strong>sasl_encodev</strong> - Encode data for transport to authenticated host</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_erasebuffer.html"><strong>sasl_erasebuffer</strong> - erase buffer</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_errdetail.html"><strong>sasl_errdetail</strong> - Retrieve detailed information about an error</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_errors.html"><strong>sasl_errors</strong> - SASL error codes</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_errstring.html"><strong>sasl_errstring</strong> - Translate a SASL return code to a human-readable form</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getcallback_t.html"><strong>sasl_getcallback_t</strong> - callback function to lookup a sasl_callback_t for a connection</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getconfpath_t.html"><strong>sasl_getconfpath_t</strong> - The SASL callback to indicate location of the config files</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getopt_t.html"><strong>sasl_getopt_t</strong> - The SASL get option callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getpath_t.html"><strong>sasl_getpath_t</strong> - The SASL callback to indicate location of the mechanism drivers</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getprop.html"><strong>sasl_getprop</strong> - Get a SASL property</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getrealm_t.html"><strong>sasl_getrealm_t</strong> - Realm Acquisition Callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getsecret_t.html"><strong>sasl_getsecret_t</strong> - The SASL callback for secrets (passwords)</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_getsimple_t.html"><strong>sasl_getsimple_t</strong> - The SASL callback for username/authname/realm</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_global_listmech.html"><strong>sasl_global_listmech</strong> - Retrieve a list of the supported SASL mechanisms</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_idle.html"><strong>sasl_idle</strong> - Perform precalculations during an idle period</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_listmech.html"><strong>sasl_listmech</strong> - Retrieve a list of the supported SASL mechanisms</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_log_t.html"><strong>sasl_log_t</strong> - The SASL logging callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_add_plugin.html"><strong>sasl_server_add_plugin</strong> - add a SASL server plugin</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_done.html"><strong>sasl_server_done</strong> - Cleanup function</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_init.html"><strong>sasl_server_init</strong> - SASL server authentication initialization</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_new.html"><strong>sasl_server_new</strong> - Create a new server authentication object</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_plug_init_t.html"><strong>sasl_server_plug_init_t</strong> - server plug‐in entry point</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_start.html"><strong>sasl_server_start</strong> - Begin an authentication negotiation</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_step.html"><strong>sasl_server_step</strong> - Perform a step in the authentication negotiation</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_userdb_checkpass_t.html"><strong>sasl_server_userdb_checkpass_t</strong> - Plaintext Password Verification Callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_server_userdb_setpass_t.html"><strong>sasl_server_userdb_setpass_t</strong> - UserDB Plaintext Password Setting Callback</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_set_alloc.html"><strong>sasl_set_alloc</strong> - set the memory allocation functions used by the SASL library</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_set_mutex.html"><strong>sasl_set_mutex</strong> - set the mutex lock functions used by the SASL library</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_seterror.html"><strong>sasl_seterror</strong> - set the error string</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_setpass.html"><strong>sasl_setpass</strong> - Check a plaintext password</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_setprop.html"><strong>sasl_setprop</strong> - Set a SASL property</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_user_exists.html"><strong>sasl_user_exists</strong> - Check if a user exists on server</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_usererr.html"><strong>sasl_usererr</strong> - Remove information leak about accounts from sasl error codes</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_utf8verify.html"><strong>sasl_utf8verify</strong> - Verify a string is valid utf8</a></li> <li class="toctree-l4"><a class="reference internal" href="../reference/manpages/library/sasl_verifyfile_t.html"><strong>sasl_verifyfile_t</strong> - The SASL file verification</a></li> </ul> </li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../auxiliary_properties.html">Auxiliary Properties</a><ul> <li class="toctree-l3"><a class="reference internal" href="../auxiliary_properties.html#auxiliary-properties-and-the-glue-layer">Auxiliary Properties and the Glue Layer</a></li> <li class="toctree-l3"><a class="reference internal" href="../auxiliary_properties.html#passwords-and-other-data">Passwords and other Data</a></li> <li class="toctree-l3"><a class="reference internal" href="../auxiliary_properties.html#sasldb">sasldb</a></li> <li class="toctree-l3"><a class="reference internal" href="../auxiliary_properties.html#ldapdb">ldapdb</a></li> <li class="toctree-l3"><a class="reference internal" href="../auxiliary_properties.html#sql">sql</a></li> <li class="toctree-l3"><a class="reference internal" href="../auxiliary_properties.html#user-canonicalization">User Canonicalization</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../authentication_mechanisms.html">Authentication Mechanisms</a><ul> <li class="toctree-l3"><a class="reference internal" href="../authentication_mechanisms.html#mechanisms">Mechanisms</a><ul> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#anonymous">ANONYMOUS</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#cram-md5">CRAM-MD5</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#digest-md5">DIGEST-MD5</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#external">EXTERNAL</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#g2">G2</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#gssapi">GSSAPI</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#gss-spegno">GSS-SPEGNO</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#kerberos-v4">KERBEROS_V4</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#login">LOGIN</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#ntlm">NTLM</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#otp">OTP</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#passdss">PASSDSS</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#plain">PLAIN</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#scram">SCRAM</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#srp">SRP</a></li> <li class="toctree-l4"><a class="reference internal" href="../authentication_mechanisms.html#non-sasl-authentication">Non-SASL Authentication</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="../authentication_mechanisms.html#summary">Summary</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../pwcheck.html">Pwcheck</a><ul> <li class="toctree-l3"><a class="reference internal" href="../pwcheck.html#auxprop">Auxprop</a></li> <li class="toctree-l3"><a class="reference internal" href="../pwcheck.html#auxprop-hashed">Auxprop-hashed</a></li> <li class="toctree-l3"><a class="reference internal" href="../pwcheck.html#saslauthd">Saslauthd</a></li> <li class="toctree-l3"><a class="reference internal" href="../pwcheck.html#authdaemon">Authdaemon</a></li> <li class="toctree-l3"><a class="reference internal" href="../pwcheck.html#alwaystrue">Alwaystrue</a></li> <li class="toctree-l3"><a class="reference internal" href="../pwcheck.html#auto-transition">Auto Transition</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../faq.html">Frequently Asked Questions</a><ul> <li class="toctree-l3"><a class="reference internal" href="../faqs/authorize-vs-authenticate.html">What is the difference between an Authorization ID and a Authentication ID?</a></li> <li class="toctree-l3"><a class="reference internal" href="../faqs/crammd5-digestmd5.html">Why do CRAM-MD5 and DIGEST-MD5 not work with CyrusSaslauthd?</a></li> <li class="toctree-l3"><a class="reference internal" href="../faqs/openldap-sasl-gssapi.html">How do I configure OpenLDAP +SASL+GSSAPI?</a></li> <li class="toctree-l3"><a class="reference internal" href="../faqs/plaintextpasswords.html">Why does CyrusSasl store plaintext passwords in its databases?</a></li> <li class="toctree-l3"><a class="reference internal" href="../faqs/rfcs.html">RFCs and drafts</a></li> <li class="toctree-l3"><a class="reference internal" href="../faqs/upgrade-saslv2.html">Why am I having a problem running dbconverter-2 to upgrade from SASLv1 to SASLv2?</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="../resources.html">Other Documentation & Resources</a></li> </ul> </li> <li class="toctree-l1 current"><a class="reference internal" href="../../developer.html">Developers</a><ul class="current"> <li class="toctree-l2"><a class="reference internal" href="../appconvert.html">Converting Applications from v1 to v2</a><ul> <li class="toctree-l3"><a class="reference internal" href="../appconvert.html#tips-for-both-clients-and-servers">Tips for both clients and servers</a></li> <li class="toctree-l3"><a class="reference internal" href="../appconvert.html#tips-for-clients">Tips for clients</a></li> <li class="toctree-l3"><a class="reference internal" href="../appconvert.html#tips-for-servers">Tips for Servers</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="programming.html">Application Programmer’s Guide</a><ul> <li class="toctree-l3"><a class="reference internal" href="programming.html#introduction">Introduction</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#about-this-guide">About this Guide</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#what-is-sasl">What is SASL?</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#background">Background</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#how-did-the-world-work-before-sasl">How did the world work before SASL?</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#sasl-to-the-rescue">SASL to the rescue!</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#briefly">Briefly</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#what-is-the-cyrus-sasl-library-good-for">What is the Cyrus SASL library good for?</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#what-does-the-cyrus-sasl-library-do">What does the Cyrus SASL library do?</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#what-doesn-t-the-cyrus-sasl-library-do">What doesn’t the Cyrus SASL library do?</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#client-only-section">Client-only Section</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#a-typical-interaction-from-the-client-s-perspective">A typical interaction from the client’s perspective</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#how-does-this-look-in-code">How does this look in code</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#server-only-section">Server-only Section</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#a-typical-interaction-from-the-server-s-perspective">A typical interaction from the server’s perspective</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#id1">How does this look in code?</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#common-section">Common Section</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#callbacks-and-interactions">Callbacks and Interactions</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#security-layers">Security layers</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#example-applications-that-come-with-the-cyrus-sasl-library">Example applications that come with the Cyrus SASL library</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#sample-client-and-sample-server"><cite>sample-client</cite> and <cite>sample-server</cite></a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#cyrus-imapd-v2-1-0-or-later">Cyrus imapd v2.1.0 or later</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#imtest-from-cyrus-2-1-0-or-later"><cite>imtest</cite>, from Cyrus 2.1.0 or later</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="programming.html#miscellaneous-information">Miscellaneous Information</a><ul> <li class="toctree-l4"><a class="reference internal" href="programming.html#empty-exchanges">Empty exchanges</a></li> <li class="toctree-l4"><a class="reference internal" href="programming.html#idle">Idle</a></li> </ul> </li> </ul> </li> <li class="toctree-l2 current"><a class="current reference internal" href="#">Plugin Programmer’s Guide</a><ul> <li class="toctree-l3"><a class="reference internal" href="#introduction">Introduction</a><ul> <li class="toctree-l4"><a class="reference internal" href="#about-this-guide">About this Guide</a></li> <li class="toctree-l4"><a class="reference internal" href="#what-is-sasl">What is SASL?</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="#common-section">Common Section</a><ul> <li class="toctree-l4"><a class="reference internal" href="#overview-of-plugin-programming">Overview of Plugin Programming</a></li> <li class="toctree-l4"><a class="reference internal" href="#use-of-sasl-utils-t">Use of sasl_utils_t</a></li> <li class="toctree-l4"><a class="reference internal" href="#error-reporting">Error Reporting</a></li> <li class="toctree-l4"><a class="reference internal" href="#memory-allocation">Memory Allocation</a></li> <li class="toctree-l4"><a class="reference internal" href="#client-send-first-server-send-last">Client Send First / Server Send Last</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="#client-plugins">Client Plugins</a></li> <li class="toctree-l3"><a class="reference internal" href="#server-plugins">Server Plugins</a></li> <li class="toctree-l3"><a class="reference internal" href="#user-canonicalization-canon-user-plugins">User Canonicalization (canon_user) Plugins</a></li> <li class="toctree-l3"><a class="reference internal" href="#auxiliary-property-auxprop-plugins">Auxiliary Property (auxprop) Plugins</a></li> </ul> </li> <li class="toctree-l2"><a class="reference internal" href="testing.html">Testing</a><ul> <li class="toctree-l3"><a class="reference internal" href="testing.html#testing-the-cmu-sasl-library-with-the-included-sample-applications">Testing the CMU SASL Library with the included sample applications</a><ul> <li class="toctree-l4"><a class="reference internal" href="testing.html#example">Example</a></li> </ul> </li> <li class="toctree-l3"><a class="reference internal" href="testing.html#running-the-testsuite-application">Running the Testsuite application</a></li> </ul> </li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="../../support.html">Support/Community</a></li> </ul> <p class="caption"><span class="caption-text">IMAP</span></p> <ul> <li class="toctree-l1"><a class="reference external" href="http://www.cyrusimap.org">Cyrus IMAP</a></li> </ul> </div> </nav> <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"> <nav class="wy-nav-top" role="navigation" aria-label="top navigation"> <i data-toggle="wy-nav-top" class="fa fa-bars"></i> <a href="../../index.html">Cyrus SASL</a> </nav> <div class="wy-nav-content"> <div class="rst-content"> <div role="navigation" aria-label="breadcrumbs navigation"> <ul class="wy-breadcrumbs"> <li><a href="../../index.html">Docs v2.1.27</a> »</li> <li><a href="../../developer.html">Developers</a> »</li> <li>Plugin Programmer’s Guide</li> <li class="wy-breadcrumbs-aside"> <a href="https://github.com/cyrusimap/cyrus-sasl/blob/master/docsrc/sasl/developer/plugprog.rst" class="fa fa-github"> Edit on GitHub</a> </li> </ul> <hr/> </div> <div role="main" class="document"> <div class="section" id="plugin-programmer-s-guide"> <span id="plugprog"></span><h1>Plugin Programmer’s Guide<a class="headerlink" href="#plugin-programmer-s-guide" title="Permalink to this headline">¶</a></h1> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">NOTE: This is a work in progress. Any contributions would be <em>very</em> appreciated.</p> </div> <div class="contents local topic" id="contents"> <ul class="simple"> <li><a class="reference internal" href="#introduction" id="id1">Introduction</a><ul> <li><a class="reference internal" href="#about-this-guide" id="id2">About this Guide</a></li> <li><a class="reference internal" href="#what-is-sasl" id="id3">What is SASL?</a></li> </ul> </li> <li><a class="reference internal" href="#common-section" id="id4">Common Section</a><ul> <li><a class="reference internal" href="#overview-of-plugin-programming" id="id5">Overview of Plugin Programming</a></li> <li><a class="reference internal" href="#use-of-sasl-utils-t" id="id6">Use of sasl_utils_t</a></li> <li><a class="reference internal" href="#error-reporting" id="id7">Error Reporting</a></li> <li><a class="reference internal" href="#memory-allocation" id="id8">Memory Allocation</a></li> <li><a class="reference internal" href="#client-send-first-server-send-last" id="id9">Client Send First / Server Send Last</a></li> </ul> </li> <li><a class="reference internal" href="#client-plugins" id="id10">Client Plugins</a></li> <li><a class="reference internal" href="#server-plugins" id="id11">Server Plugins</a></li> <li><a class="reference internal" href="#user-canonicalization-canon-user-plugins" id="id12">User Canonicalization (canon_user) Plugins</a></li> <li><a class="reference internal" href="#auxiliary-property-auxprop-plugins" id="id13">Auxiliary Property (auxprop) Plugins</a></li> </ul> </div> <div class="section" id="introduction"> <h2><a class="toc-backref" href="#id1">Introduction</a><a class="headerlink" href="#introduction" title="Permalink to this headline">¶</a></h2> <div class="section" id="about-this-guide"> <h3><a class="toc-backref" href="#id2">About this Guide</a><a class="headerlink" href="#about-this-guide" title="Permalink to this headline">¶</a></h3> <p>This guide gives a brief overview on the things that one needs to know to write a <a class="reference internal" href="../authentication_mechanisms.html#authentication-mechanisms"><span class="std std-ref">mechanism</span></a> for the SASLv2 API (and thus Cyrus SASLv2). Note that this page is a brief overview and that the authoritative documentation are the header files included in the SASL distribution. If you have any questions, please feel free to contact the <a class="reference external" href="https://www.cyrusimap.org/contribute.html#contribute" title="(in Cyrus IMAP v3.0.8)"><span class="xref std std-ref">Cyrus development team</span></a>.</p> <p>Please note that this guide is only intended for developers looking to write mechanisms for the SASLv2 API, and that application programmers should be reading the <a class="reference internal" href="programming.html#programming"><span class="std std-ref">Application Programming Guide</span></a> instead.</p> </div> <div class="section" id="what-is-sasl"> <h3><a class="toc-backref" href="#id3">What is SASL?</a><a class="headerlink" href="#what-is-sasl" title="Permalink to this headline">¶</a></h3> <p>A description of SASL is covered in detail in the <a class="reference internal" href="programming.html#programming"><span class="std std-ref">programmer’s guide</span></a>, which mechanism developers should probably read first anyway to become familiar with development using the SASL library.</p> </div> </div> <div class="section" id="common-section"> <h2><a class="toc-backref" href="#id4">Common Section</a><a class="headerlink" href="#common-section" title="Permalink to this headline">¶</a></h2> <div class="section" id="overview-of-plugin-programming"> <h3><a class="toc-backref" href="#id5">Overview of Plugin Programming</a><a class="headerlink" href="#overview-of-plugin-programming" title="Permalink to this headline">¶</a></h3> <p>The basic idea behind programming plugins for Cyrus SASL rests in the ability to dlopen a shared library. Thus, all plugins should be shared libraries. It is recommended that they are libtool libraries for portability reasons (Cyrus SASL parses .la files to get the appropriate name to dlopen), but they can have an extention of .so as well.</p> <p>All plugins should live in the same directory (generally /usr/lib/sasl2), which the glue code (that is, the interface layer that sits between the plugins and the application) scans when one of the init functions (sasl_server_init or sasl_client_init) is called. Cyrus SASL then attempts to open each library and run an initialization function. If the initialization function succeeds, and the versions match, then the glue code determines that the load was successful and the plugin is available for use.</p> <p>There are serveral types of plugins (note that a given plugin library may contain any or all of the following in combination, though such a plugin would be a beast!):</p> <dl class="docutils"> <dt>Mechanism Plugins</dt> <dd>These plugins implement mechanisms for authentication, and are the majority of the plugins included with Cyrus SASL. Generally implementing both a client and a server side they take care of the authentication process.</dd> <dt>User Canonicalization Plugins</dt> <dd>These plugins enable differing ways of canonicalizing authentication and authorization IDs.</dd> <dt>Auxiliary Property Plugins</dt> <dd>These plugins allow auxilliary properties about user accounts to be looked up, such as passwords. Cyrus SASL includes a plugin to read sasldb files, for example.</dd> </dl> </div> <div class="section" id="use-of-sasl-utils-t"> <h3><a class="toc-backref" href="#id6">Use of sasl_utils_t</a><a class="headerlink" href="#use-of-sasl-utils-t" title="Permalink to this headline">¶</a></h3> <p>Because of the way that shared library plugins are loaded for both speed and namespace reasons, the symbol tables are not shared across plugins. Thus, the only interface that the plugin should assume it has to the outside world is through the <code class="docutils literal"><span class="pre">sasl_utils_t</span></code> structure (or through links that it specifically requires). Likewise, the glue code has no (and will use no) interface into the plugin other than the contents of the structures that are passed back to it by the initialization function.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Do not assume you have access to any functions except through links that your library explicitly makes or through what is provided via the <code class="docutils literal"><span class="pre">sasl_utils_t</span></code> structure.</p> </div> </div> <div class="section" id="error-reporting"> <h3><a class="toc-backref" href="#id7">Error Reporting</a><a class="headerlink" href="#error-reporting" title="Permalink to this headline">¶</a></h3> <p>Error reporting is very important for failed authentication tracking and helping to debug installations or authentication problems. For that reason, in addition to the standard SASL return codes, the glue code provides an interface to its seterror function (via <code class="docutils literal"><span class="pre">sasl_utils_t</span></code>). This function sets detailed error information for a given connection.</p> <p>In order to ensure consistency of this information, it is the responsibility of the deepest function with access to the sasl_conn_t make the call to set the errdetail string.</p> </div> <div class="section" id="memory-allocation"> <h3><a class="toc-backref" href="#id8">Memory Allocation</a><a class="headerlink" href="#memory-allocation" title="Permalink to this headline">¶</a></h3> <p>Memory allocation in SASLv2 follows the simple paradigm that <strong>if you allocate it, you free it</strong>. This improves portability, and allows for a large performance improvement over SASLv1. To prevent memory leaks (especially in the mechanism plugins), please ensure that you follow this paradigm.</p> </div> <div class="section" id="client-send-first-server-send-last"> <h3><a class="toc-backref" href="#id9">Client Send First / Server Send Last</a><a class="headerlink" href="#client-send-first-server-send-last" title="Permalink to this headline">¶</a></h3> <p>Mechanism plugins used to have to worry about the situation where they needed clients to send first (or server to send last), yet the protocol did not support it. Luckily, this is now handled by the glue code, provided that the plugin declares the appropriate flags in the structure returned by its init function. Thus, the step functions will not have to worry about these issues and can be implemented knowing they will be called only when the application actually has data for them and/or will allow them to send data. These flags are as follows:</p> <dl class="docutils"> <dt>SASL_FEAT_WANT_CLIENT_FIRST</dt> <dd>The mechanism has the client side send first always. (e.g. PLAIN)</dd> <dt>SASL_FEAT_SERVER_FIRST</dt> <dd>The mechanism has the server side send first always. (e.g. CRAM-MD5)</dd> </dl> <p>If neither flag is set, the mechanism will handle the client-send first situation internally, because the client may or may not send first. (e.g. DIGEST-MD5). In this case, the plugin must intelligently check for the presence (or absence) of clientin/serverin data. Note that the optional client send-first is only possible when the protocol permits an initial response.</p> <p>The server send last situation is handled by the plugin intelligently setting *serverout when the step function returns SASL_OK.</p> <ul class="simple"> <li>For mechanisms which never send last (e.g. PLAIN), *serverout must be set to NULL.</li> <li>For mechanisms which always send last (e.g. DIGEST-MD5), *serverout must point to the success data.</li> <li>For mechanisms in which the server may or may not send last (e.g. SRP), *serverout must be set accordingly.</li> </ul> </div> </div> <div class="section" id="client-plugins"> <span id="plugprog-client"></span><h2><a class="toc-backref" href="#id10">Client Plugins</a><a class="headerlink" href="#client-plugins" title="Permalink to this headline">¶</a></h2> <p>Client-side mechanism plugins are generally included in the same plugin with their <a class="reference internal" href="#plugprog-server"><span class="std std-ref">server</span></a> counterpart, though this is not a requirement. They take care of the client-side of the SASL negotiation. For a simple example, see the ANONYMOUS plugin. Client plugins must export <code class="docutils literal"><span class="pre">sasl_client_plug_init</span></code> which returns a <code class="docutils literal"><span class="pre">sasl_client_plug_t</span></code> in order to load. The structure has several functional members and a global context (which applies to all connections using the plugin). The important ones are described briefly here.</p> <dl class="docutils"> <dt>mech_new</dt> <dd><p class="first">Called at the beginning of each connection, (on a call to sasl_client_start),</p> <p class="last">mech_new does mechanism-specific initialization, and if necessary allocates a connection context (which the glue code keeps track of for it). mech_new does not actually send any data to the client, it simply allocates the context.</p> </dd> <dt>mech_step</dt> <dd><p class="first">Called from <code class="docutils literal"><span class="pre">sasl_client_start</span></code> and <code class="docutils literal"><span class="pre">sasl_client_step</span></code>, this function does the actual work of the client side of the authentication. If authentication is successful, it should return SASL_OK, otherwise it should return a valid SASL error code (and call seterror).</p> <p>This should also set up the oparams structure before returning SASL_OK, including any security layer information (in the way of callbacks).</p> <p class="last">Note that as soon as the client has both the authentication and authorization IDs, it MUST call the canon_user function provided in its params structure (for both the authentication and authorization IDs, with SASL_CU_AUTHID and SASL_CU_AUTHZID respectively).</p> </dd> <dt>mech_dispose</dt> <dd>Called to dispose of a connection context. This is only called when the connection will no longer be used (e.g. when <code class="docutils literal"><span class="pre">sasl_dispose</span></code> is called)</dd> <dt>mech_free</dt> <dd>Called when the sasl library is shutting down (by <code class="docutils literal"><span class="pre">sasl_client_done/sasl_server_done/sasl_done</span></code>). Intended to free any global state of the plugin.</dd> </dl> </div> <div class="section" id="server-plugins"> <span id="plugprog-server"></span><h2><a class="toc-backref" href="#id11">Server Plugins</a><a class="headerlink" href="#server-plugins" title="Permalink to this headline">¶</a></h2> <p>Server-side mechanism plugins are generally included in the same plugin with their <a class="reference internal" href="#plugprog-client"><span class="std std-ref">client</span></a> counterpart, though this is not a requirement. They take care of the server-side of the SASL negotiation, and are generally more complicated than their client-side counterparts. For a simple example, see the ANONYMOUS plugin.</p> <p>Server plugins must export <code class="docutils literal"><span class="pre">sasl_server_plug_init</span></code> which returns a <code class="docutils literal"><span class="pre">sasl_server_plug_t</span></code> in order to load. The structure has several functional members and a global context (which applies to all connections using the plugin). The important ones are described briefly here.</p> <dl class="docutils"> <dt>mech_new</dt> <dd><p class="first">Called at the beginning of each connection, (on a call to sasl_client_start),</p> <p class="last">mech_new does mechanism-specific initialization, and if necessary allocates a connection context (which the glue code keeps track of for it). mech_new does not actually send any data to the client, it simply allocates the context.</p> </dd> <dt>mech_step</dt> <dd><p class="first">Called from <code class="docutils literal"><span class="pre">sasl_server_start</span></code> and <code class="docutils literal"><span class="pre">sasl_server_step</span></code>, this function does the actual work of the server side of the authentication.</p> <p>If authentication is successful, it should return SASL_OK, otherwise it should return a valid SASL error code (and call seterror). This should also set up the oparams structure before returning SASL_OK, including any security layer information (in the way of callbacks and SSF information).</p> <p>Also, as soon as the mechanism has computed both the authentication and the authorization IDs, it MUST call the canon_user function provided in the server params structure (for both the authentication and authorization IDs, with SASL_CU_AUTHID and SASL_CU_AUTHZID respectively). This action will also fill in its propctx, so any auxiliary property <em>requests</em> (for example, to lookup the password) should be done before the request to canonicalize the authentication id. Authorization ID lookups do not occur until after the plugin returns success to the SASL library.</p> <p class="last">Before returning SASL_OK, <code class="docutils literal"><span class="pre">mech_step</span></code> must fill in the oparams fields for which it is responsible, that is, <code class="docutils literal"><span class="pre">doneflag</span></code> (set to 1 to indicate a complete exchange), <code class="docutils literal"><span class="pre">maxoutbuf</span></code>, or the maximum output size it can do at once for a security layer, <code class="docutils literal"><span class="pre">mech_ssf</span></code> or the supplied SSF of the security layer, and <code class="docutils literal"><span class="pre">encode</span></code>, <code class="docutils literal"><span class="pre">decode</span></code>, <code class="docutils literal"><span class="pre">encode_context</span></code>, and <code class="docutils literal"><span class="pre">decode_context</span></code>, which are what the glue code will call on calls to <code class="docutils literal"><span class="pre">sasl_encode</span></code>, <code class="docutils literal"><span class="pre">sasl_encodev</span></code>, and <code class="docutils literal"><span class="pre">sasl_decode</span></code>.</p> </dd> <dt>mech_dispose</dt> <dd>Called to dispose of a connection context. This is only called when the connection will no longer be used (e.g. when <code class="docutils literal"><span class="pre">sasl_dispose</span></code> is called)</dd> <dt>mech_free</dt> <dd>Called when the sasl library is shutting down (by <code class="docutils literal"><span class="pre">sasl_client_done/sasl_server_done/sasl_done</span></code>). Intended to free any global state of the plugin.</dd> <dt>setpass</dt> <dd>Called to set a user’s password. This allows mechanisms to support their own internal password or secret database.</dd> <dt>mech_avail</dt> <dd>Called by the first call to <code class="docutils literal"><span class="pre">sasl_listmech</span></code>, it checks to see if the mechanism is available for the given user, and MAY allocate a connection context (thus avoiding a call to <code class="docutils literal"><span class="pre">mech_new</span></code>). However it should not do this without significant performance benefit as it forces the glue code to keep track of extra contexts that may not be used.</dd> </dl> </div> <div class="section" id="user-canonicalization-canon-user-plugins"> <h2><a class="toc-backref" href="#id12">User Canonicalization (canon_user) Plugins</a><a class="headerlink" href="#user-canonicalization-canon-user-plugins" title="Permalink to this headline">¶</a></h2> <p>User Canonicalization plugins allow for nonstandard ways of canonicalizing the username. They are subject to the following requirements:</p> <ul class="simple"> <li>They must copy their output into the provided output buffers.</li> <li>The output buffers may be the same as the input buffers.</li> <li>They must function for the case which is only an authentication ID (flags == SASL_CU_AUTHID) or only an authorization ID (flags == SASL_CU_AUTHZID) or both (flags == SASL_CU_AUTHID | SASL_CU_AUTHZID)</li> </ul> <p>User canonicalization plugins must export a <code class="docutils literal"><span class="pre">sasl_canonuser_init</span></code> function which returns a <code class="docutils literal"><span class="pre">sasl_canonuser_plug_t</span></code> in order to load successfully. They must implement at least one of the <code class="docutils literal"><span class="pre">canon_user_client</span></code> or <code class="docutils literal"><span class="pre">canon_user_server</span></code> members of the <code class="docutils literal"><span class="pre">sasl_canonuser_plug_t</span></code>. The INTERNAL canon_user plugin that is inside of the glue code implements both in the same way.</p> </div> <div class="section" id="auxiliary-property-auxprop-plugins"> <h2><a class="toc-backref" href="#id13">Auxiliary Property (auxprop) Plugins</a><a class="headerlink" href="#auxiliary-property-auxprop-plugins" title="Permalink to this headline">¶</a></h2> <p>Perhaps the most exciting addition in SASLv2, Auxprop plugins allow for an easy way to perform password and secret lookups (as well as other information needed for authentication and authorization) from directory services, and in the same request allow the application to receive properties that it needs to provide the service.</p> <p>Auxprop plugins need to export the <code class="docutils literal"><span class="pre">sasl_auxprop_init</span></code> function and pass back a <code class="docutils literal"><span class="pre">sasl_auxprop_plug_t</span></code> in order to load successfully. The sasldb plugin included with the Cyrus SASL distribution would be a good place to start.</p> <p>Interfacing with property contexts is extremely well documented in <code class="docutils literal"><span class="pre">prop.h</span></code> and so that is omitted here. The only important note is to be sure that you are using the interfaces provided through the <code class="docutils literal"><span class="pre">sasl_utils_t</span></code> structure and not calling the functions directly.</p> <p>To successfully implement an auxprop plugin there is only one required function to implement, that is the <code class="docutils literal"><span class="pre">auxprop_lookup</span></code> member of the <code class="docutils literal"><span class="pre">sasl_auxprop_plug_t</span></code>. This is called just after canonicalization of the username, with the canonicalized username. It can then do whatever lookups are necessary for any of the requested auxiliary properties.</p> </div> </div> </div> <footer> <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation"> <a href="testing.html" class="btn btn-neutral float-right" title="Testing" accesskey="n">Next <span class="fa fa-arrow-circle-right"></span></a> <a href="programming.html" class="btn btn-neutral" title="Application Programmer’s Guide" accesskey="p"><span class="fa fa-arrow-circle-left"></span> Previous</a> </div> <hr/> <div role="contentinfo"> <p> © Copyright 1993-2016, The Cyrus Team. </p> </div> Built with <a href="http://sphinx-doc.org/">Sphinx</a> 1.6.6 using a modified <a href="https://readthedocs.org">Read the Docs</a> <a href="https://github.com/snide/sphinx_rtd_theme">theme</a>. </footer> </div> </div> </section> </div> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT:'../../', VERSION:'2.1.27', COLLAPSE_INDEX:false, FILE_SUFFIX:'.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../../_static/jquery.js"></script> <script type="text/javascript" src="../../_static/underscore.js"></script> <script type="text/javascript" src="../../_static/doctools.js"></script> <script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js"></script> <script type="text/javascript" src="../../_static/js/theme.js"></script> <script type="text/javascript"> <!-- jQuery(function () { SphinxRtdTheme.StickyNav.enable(); }); --> </script> </body> </html>