cloudstack/docs/en-US/password-storage-engine.xml
2013-07-11 11:06:11 +05:30

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<?xml version='1.0' encoding='utf-8' ?>
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<section id="password-storage-engine">
<title>Changing the Default Password Encryption</title>
<para>Passwords are encoded when creating or updating users. &PRODUCT; allows you to determine the
default encoding and authentication mechanism for admin and user logins. A new configurable list
called <code>UserPasswordEncoders</code> to allow you to separately configure the order of
preference for encoding and authentication schemes. </para>
<para>Additionally, plain text user authenticator has been changed to use SHA256SALT as the
default encoding algorithm because it is more secure compared to MD5 hashing. It does a simple
string comparison between retrieved and supplied login passwords instead of comparing the
retrieved md5 hash of the stored password against the supplied md5 hash of the password because
clients no longer hash the password. The following method determines what encoding scheme is
used to encode the password supplied during user creation or modification. </para>
<para>When a new user is created, the user password is encoded by using the first valid encoder
loaded as per the sequence specified in the <code>UserPasswordEncoders</code> property in the
<filename>ComponentContext.xml</filename> or <filename>nonossComponentContext.xml</filename>
files. The order of authentication schemes is determined by the <code>UserAuthenticators</code>
property in the same files. When a new authenticator or encoder is added, you can add them to
this list. While doing so, ensure that the new authenticator or encoder is specified as a bean
in both these files. The administrator can change the ordering of both these properties as
preferred to change the order of schemes. Modify the following list properties available in
<filename>client/tomcatconf/nonossComponentContext.xml.in</filename> or
<filename>client/tomcatconf/componentContext.xml.in</filename> as applicable, to the desired
order:</para>
<programlisting>&lt;property name="UserAuthenticators"&gt;
&lt;list&gt;
&lt;ref bean="SHA256SaltedUserAuthenticator"/&gt;
&lt;ref bean="MD5UserAuthenticator"/&gt;
&lt;ref bean="LDAPUserAuthenticator"/&gt;
&lt;ref bean="PlainTextUserAuthenticator"/&gt;
&lt;/list&gt;
&lt;/property&gt;
&lt;property name="UserPasswordEncoders"&gt;
&lt;list&gt;
&lt;ref bean="SHA256SaltedUserAuthenticator"/&gt;
&lt;ref bean="MD5UserAuthenticator"/&gt;
&lt;ref bean="LDAPUserAuthenticator"/&gt;
&lt;ref bean="PlainTextUserAuthenticator"/&gt;
&lt;/list&gt;</programlisting>
<para>In the above default ordering, SHA256Salt is used first for
<code>UserPasswordEncoders</code>. If the module is found and encoding returns a valid value,
the encoded password is stored in the user table's password column. If it fails for any reason,
the MD5UserAuthenticator will be tried next, and the order continues. For
<code>UserAuthenticators</code>, SHA256Salt authentication is tried first. If it succeeds, the
user is logged into the Management server. If it fails, MD5 is tried next, and attempts
continues until any of them succeeds and the user logs in . If none of them works, the user is
returned an invalid credential message. </para>
</section>