ldap_compare

Description

mixed ldap_compare ( resource link_identifier, string dn, string attribute, string value )

Returns TRUE if value matches otherwise returns FALSE. Returns -1 on error.

ldap_compare() is used to compare value of attribute to value of same attribute in LDAP directory entry specified with dn.

The following example demonstrates how to check whether or not given password matches the one defined in DN specified entry.

例子 1. Complete example of password check


<?php

$ds=ldap_connect("localhost");  // assuming the LDAP server is on this host
      
if ($ds) {

    // bind 
    if (ldap_bind($ds)) {

        // prepare data
        $dn = "cn=Matti Meikku, ou=My Unit, o=My Company, c=FI";
        $value = "secretpassword";
        $attr = "password"; 

        // compare value
        $r=ldap_compare($ds, $dn, $attr, $value);

        if ($r === -1) {
            echo "Error: " . ldap_error($ds);
        } elseif ($r === true) {
            echo "Password correct.";
        } elseif ($r === false) {
            echo "Wrong guess! Password incorrect.";
        }

    } else {
        echo "Unable to bind to LDAP server.";
    }          

    ldap_close($ds);

} else {
    echo "Unable to connect to LDAP server.";
}
?>

警告

ldap_compare() can NOT be used to compare BINARY values!

注: This function was added in 4.0.2.

add a note User Contributed Notes

oudejans at zeelandnet dot nl
11-Apr-2005 08:10


With PHP 4.3.* is Password no longer a valid attribute.. try to use userPassword

chuck+ldap at 2006 dot snew dot com
06-Aug-2004 01:08


Just a side note that this is not how you'd ever AUTHENTICATE someone, just an example code.



The common way to authenticate is to get the users name, use search and perhaps selection to the user to get her DN (single value) then attempt to BIND to the ldapserver using that dn and the offered password.  If it works, then it's the right password.



Note that the password offered MUST NOT BE EMPTY or many LDAPs will presume you meant to authenticate anonymously and it will succeed, leaving you thinking it's the right password.

Brian Kerhin <kerhin at bigfoot dot com>
31-Jan-2001 10:13


Not probably, will.  With PHP 4.0.4 and openldap 1.2.9 this little script, even with the correct attributes for the password does not do the job.  Would superb if it did!

334647 at swin dot edu dot au
26-Oct-2000 10:06


Interesting example. Apart from the fact that very few people would allow comaprisions of the password attribute for security reasons. The attribute name of "password" does not match the usual schemas.





The usual method of user id + password verification is to attempt to bind using the supplied credentials.





Ldap compare on password values will probably fail with ns directroy server and openldap v2+ becuase of server support for password hashing.

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