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<title>Options for Cyrus SASL</title>
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<h1>Options for Cyrus SASL</h1>
<p>This document contains information on what options are used by the
Cyrus SASL library and bundled mechanisms. The most commonly used
options (and those that are therefore most commonly misunderstood
are <b>pwcheck_method</b> and <b>auxprop_plugin</b>. Please ensure
that you have configured these correctly if things don't seem to
be working right. Additionally, <b>mech_list</b> can be an easy
way to limit what mechanisms a given application will use.</p>
<TABLE BORDER WIDTH=95%>
<TR><TH>Option</TH><TH>Used By</TH><TH>Description</TH><TH>Default</TH></TR>
<TR>
<TD>authdaemond_path</TD><TD>SASL Library</TD>
<TD>Path to Courier-IMAP authdaemond's unix socket.
Only applicable when pwcheck_method is set to authdaemond.</TD><TD>/dev/null</TD>
</TR>
<TR>
<TD>auto_transition</TD><TD>SASL Library</TD>
<TD>When set to 'yes' or 'noplain',
and when using an auxprop plugin, automatically transition
users to other mechs when they do a successful plaintext
authentication. When set to 'noplain', only non-plaintext secrets
will be written. <I>Note that the only mechs (as currently
implemented) which don't use plaintext secrets are
OTP and SRP.</I></TD><TD>no</TD>
</TR>
<TR>
<TD>auxprop_plugin</TD><TD>Auxiliary Property Plugin</TD>
<TD>Name of auxiliary plugin to use, you may specify a space-separated
list of plugin names, and the plugins will be queried in order</TD>
<TD>(null) - querys all plugins</TD>
</TR>
<TR>
<TD>canon_user_plugin</TD><TD>SASL Library</TD>
<TD>Name of canon_user plugin to use</TD><TD>INTERNAL</TD>
</TR>
<TR>
<TD>keytab</TD><TD>GSSAPI</TD> <TD>Location of keytab
file</TD><TD><tt>/etc/krb5.keytab</tt> (system dependant)</TD>
</TR>
<TR>
<TD>ldapdb_uri</TD><TD>LDAPDB plugin</TD>
<TD>ldap server uri, you can specify a space-separated list of URIs -
ldapi:// or ldaps://ldap1/ ldaps://ldap2/</TD>
<TD>none</TD>
</TR>
<TR>
<TD>ldapdb_id</TD><TD>LDAPDB plugin</TD>
<TD>ldap SASL authentication id</TD>
<TD>none</TD>
</TR>
<TR>
<TD>ldapdb_mech</TD><TD>LDAPDB plugin</TD>
<TD>ldap SASL mechanism for authentication</TD>
<TD>none</TD>
</TR>
<TR>
<TD>ldapdb_pw</TD><TD>LDAPDB plugin</TD>
<TD>ldap password for SASL authentication id</TD>
<TD>none</TD>
</TR>
<TR>
<TD>ldapdb_rc</TD><TD>LDAPDB plugin</TD>
<TD>The filename specified here will be put into the server's LDAPRC
environment variable, and libldap-specific config options may be set
in that ldaprc file. The main purpose behind this option is to allow
a client TLS certificate to be configured, so that SASL/EXTERNAL may
be used between the SASL server and the LDAP server. This is the most
optimal way to use this plugin when the servers are on separate machines.</TD>
<TD>none</TD>
</TR>
<TR>
<TD>ldapdb_starttls</TD><TD>LDAPDB plugin</TD>
<TD>Use StartTLS. This option may be set to 'try' or 'demand'.
When set to "try" any failure in StartTLS is ignored.
When set to "demand" then any failure aborts the connection.</TD>
<TD>none</TD>
</TR>
<TR>
<TD>ldapdb_canon_attr</TD><TD>LDAPDB plugin</TD>
<TD>Use the value of the specified attribute as the user's
canonical name. The attribute will be looked up in the user's LDAP
entry. This setting must be configured in order to use LDAPDB as
a canonuser plugin.</TD>
<TD>none</TD>
</TR>
<TR>
<TD>log_level</TD><TD>SASL Library</TD>
<TD><b>Numeric</b> Logging Level (see <TT>SASL_LOG_*</TT> in <tt>sasl.h</tt>
for values and descriptions</TD>
<TD>1 (SASL_LOG_ERR)</TD>
</TR>
<TR>
<TD>mech_list</TD><TD>SASL Library</TD>
<TD>Whitespace separated list of mechanisms to allow (e.g. 'plain
otp'). Used to restrict the mechanisms to a subset of the installed
plugins.</TD><TD>(use all available plugins)</TD>
</TR>
<TR>
<TD>ntlm_server</TD><TD>NTLM (server)</TD>
<TD>Comma separated list of servernames (WinNT, Win2K, Samba, etc) to
which authentication will be proxied.</TD>
<TD>(null) - perform authentication internally</TD>
</TR>
<TR>
<TD>ntlm_v2</TD><TD>NTLM (client)</TD>
<TD>Send NTLMv2 responses to the server.</TD>
<TD>no (send NTLMv1)</TD>
</TR>
<TR>
<TD>opiekeys</TD><TD>OTP (with OPIE)</TD>
<TD>Location of the opiekeys file</TD><TD><tt>/etc/opiekeys</tt></TD>
</TR>
<TR>
<TD>otp_mda</TD><TD>OTP (w/o OPIE)</TD>
<TD>Message digest algorithm for one-time passwords, used by sasl_setpass
(possible values: 'md4', 'md5', 'sha1')</TD><TD><tt>md5</tt></TD>
</TR>
<TR>
<TD>plugin_list</TD><TD>SASL Library</TD>
<TD>Location of Plugin list (Unsupported)</TD><TD><i>none</i></TD>
</TR>
<TR>
<TD>pwcheck_method</TD><TD>SASL Library</TD>
<TD>Whitespace separated list of mechanisms used to verify passwords,
used by sasl_checkpass (possible values: 'auxprop', 'saslauthd',
'pwcheck', 'authdaemond' [if compiled with <tt>--with-authdaemond</tt>])
and 'alwaystrue' [if compiled with <tt>--enable-alwaystrue</tt>])
</TD><TD>auxprop</TD>
</TR>
<TR>
<TD>reauth_timeout</TD><TD>DIGEST-MD5</TD>
<TD>Length in time (in minutes) that authentication info will be
cached for a fast reauth. A value of 0 will disable reauth.</TD>
<TD>0</TD>
</TR>
<TR>
<TD>saslauthd_path</TD><TD>SASL Library</TD>
<TD>Path to saslauthd run directory (<b>including</b> the "/mux" named pipe)</TD>
<TD>system dependant (generally won't need to be changed)</TD>
</TR>
<TR>
<TD>sasldb_path</TD><TD>sasldb plugin</TD>
<TD>Path to sasldb file</TD><TD><tt>/etc/sasldb2</tt> (system dependant)</TD>
<TR>
<TD>sql_engine</TD><TD>SQL plugin</TD>
<TD>Name of SQL engine to use (possible values: 'mysql', 'pgsql', 'sqlite', 'sqlite3').</TD>
<TD><tt>mysql</tt></TD>
</TR>
<TR>
<TD>sql_hostnames</TD><TD>SQL plugin</TD>
<TD>Comma separated list of SQL servers (in host[:port] format).</TD>
<TD><i>none</i> (engine dependent)</TD>
</TR>
<TR>
<TD>sql_user</TD><TD>SQL plugin</TD>
<TD>Username to use for authentication to the SQL server.</TD>
<TD><i>none</i> (engine dependent)</TD>
</TR>
<TR>
<TD>sql_passwd</TD><TD>SQL plugin</TD>
<TD>Password to use for authentication to the SQL server.</TD>
<TD><i>none</i> (engine dependent)</TD>
</TR>
<TR>
<TD>sql_database</TD><TD>SQL plugin</TD>
<TD>Name of the database which contains the auxiliary properties.</TD>
<TD><i>none</i> (engine dependent)</TD>
</TR>
<TR>
<TD>sql_select</TD><TD>SQL plugin</TD>
<TD>SELECT statement to use for fetching properties. This option is
<b>required</b> in order to use the SQL plugin.</TD>
<TD><i>none</i></TD>
</TR>
<TR>
<TD>sql_insert</TD><TD>SQL plugin</TD>
<TD>INSERT statement to use for creating properties for new users.</TD>
<TD><i>none</i></TD>
</TR>
<TR>
<TD>sql_update</TD><TD>SQL plugin</TD>
<TD>UPDATE statement to use for modifying properties.</TD>
<TD><i>none</i></TD>
</TR>
<TR>
<TD>sql_usessl</TD><TD>SQL plugin</TD>
<TD>When set to 'yes', 'on', '1' or 'true', a secure connection will
be made to the SQL server.</TD>
<TD><tt>no</tt></TD>
</TR>
<TR>
<TD>srp_mda</TD><TD>SRP</TD>
<TD>Message digest algorithm for SRP calculations
(possible values: 'md5', 'sha1', 'rmd160')</TD><TD><tt>sha1</tt></TD>
</TR>
<TR>
<TD>srvtab</TD><TD>KERBEROS_V4</TD>
<TD>Location of the srvtab file</TD><TD><tt>/etc/srvtab</tt> (system
dependant)</TD>
</TR>
</TABLE>
<h2>Notes on SQL auxprop options</h2>
<p>The <tt>sql_insert</tt> and <tt>sql_update</tt> options are
optional and are only needed if you wish to allow the SASL library
(e.g., saslpasswd2) and plugins (e.g., OTP) to write properties to the
SQL server. If used, both statements MUST be provided so that
properties can be added, changed and deleted.
<font color=red>NOTE: The columns for writable properites MUST accept NULL values.</font>
<p>The SQL statements provided in the <tt>sql_select</tt>,
<tt>sql_insert</tt> and <tt>sql_update</tt> options can contain
arguments which will be substituted with the appropriate values. The
valid arguments are:
<DL compact>
<DT><tt>%u</tt> <DD>Username whose properties are being fetched/stored.
<DT><tt>%p</tt> <DD>Name of the property being fetched/stored. This could
technically be anything, but SASL authentication will try
userPassword and cmusaslsecretMECHNAME (where MECHNAME is the
name of a SASL mechanism).
<DT><tt>%r</tt> <DD>Realm to which the user belongs. This could be the
kerberos realm, the FQDN of the computer the SASL application is
running on or whatever is after the @ on a username. (read the
realm documentation).
<DT><tt>%v</tt> <DD>Value of the property being stored (INSERT or
UPDATE only!). This could technically be anything depending on
the property itself, but is generally a userPassword.
</DL>
<font color=red>NOTE: DO NOT put quotes around the entire SQL
statement, but each individual %u, %r and %v argument MUST be
quoted.</font>
<h3>Examples:</h3>
<pre>
<tt>sql_select: SELECT %p FROM user_table WHERE username = '%u' and realm = '%r'</tt>
</pre>
would send the following statement to SQL for user "bovik" and
the default realm for the machine "madoka.surf.org.uk":
<pre>
<tt>SELECT userPassword FROM user_table WHERE username = 'bovik' and
realm = 'madoka.surf.org.uk';</tt>
</pre>
<pre>
<tt>sql_insert: INSERT INTO user_table (username, realm, %p) VALUES ('%u', '%r', '%v')</tt>
</pre>
would generate the following statement to SQL for user "bovik" in
realm "madoka.surf.org.uk" with userPassword "wert":
<pre>
<tt>INSERT INTO user_table (username, realm, userPassword) VALUES
('bovik', 'madoka.surf.org.uk', 'wert');</tt>
</pre>
<p>Note that all substitutions do not have to be used. For instance,
<pre>
<tt>SELECT password FROM auth WHERE username = '%u'</tt>
</pre>
is a valid value for <tt>sql_select</tt>.
<h2>Notes on LDAPDB plugin options</h2>
<p>
</p>
<p>Unlike other LDAP-enabled plugins for other services that are common
on the web, this plugin does not require you to configure DN search
patterns to map usernames to LDAP DNs. This plugin requires SASL name
mapping to be configured on the target slapd. This approach keeps the
LDAP-specific configuration details in one place, the slapd.conf, and
makes the configuration of remote services much simpler.</p>
<p>This plugin is not for use with slapd itself. When OpenLDAP is
built with SASL support, slapd uses its own internal auxprop and
canonuser module.
By default, without configuring anything else, slapd will fail to load
the ldapdb module when it's present. This is as it should be. If you
don't like the "auxpropfunc: error -7" message that is sent to syslog
by slapd, you can stop it by creating /usr/lib/sasl2/slapd.conf with:
<pre>auxprop_plugin: slapd</pre>
which will force the SASL library to ignore all other auxprop modules.</p>
<h3>Examples:</h3>
<pre>
ldapdb_uri: ldap://ldap.example.com
ldapdb_id: root
ldapdb_pw: secret
ldapdb_mech: DIGEST-MD5
ldapdb_canon_attr: uid
</pre>
<p>The LDAP server must be configured to map the SASL authcId "root" into a DN
that has proxy authorization privileges to every account that is allowed to
login to this server. (See the OpenLDAP Admin Guide section 10 for
details.)</p>
<pre>
ldapdb_uri: ldapi://
ldapdb_mech: EXTERNAL
</pre>
<p>This configuration assumes an LDAP server is on the same server that is
using SASL and the underlying OS is *NIX based (ldapi:// requires UNIX domain
sockets). This is fast and secure, and needs no username or password to be
stored. The slapd.conf will need to map these usernames to LDAP DNs:
<pre>
sasl-regexp uidNumber=(.*)\\+gidNumber=(.*),cn=peercred,cn=external,cn=auth
ldap:///dc=example,dc=com??sub?(&(uidNumber=$1)(gidNumber=$2))
</pre>
<pre>
sasl-regexp uid=(.*),cn=external,cn=auth
ldap:///dc=example,dc=com??sub?(uid=$1)
</pre>
</p>
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