ldap_get_values_len

ashwini at majestik dot net (2013-04-09 22:52:54)

Just a minor update to the note below from "jhgustafsson" regarding the "objectGUID" field...
Going a step further, sometimes its useful to display this GUID as a String, and Microsoft has a support article and script detailing how to convert objectGUID from Hex to String. That article is here: http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B325649
Below is a PHP function that does the same thing as Microsoft's VB script, it takes input of objectGUID in binary format and returns it formatted as a string (after converting it to Hex as a middle step). This will return the exact "objectGUID" value that is displayed for any Active Directory object in ADUC.
Example output: 3f79048f-42cd-4c77-8426-835cd9f8a3ad
function GUIDtoStr($binary_guid) {
$hex_guid = unpack("H*hex", $binary_guid);
$hex = $hex_guid["hex"];

$hex1 = substr($hex, -26, 2) . substr($hex, -28, 2) . substr($hex, -30, 2) . substr($hex, -32, 2);
$hex2 = substr($hex, -22, 2) . substr($hex, -24, 2);
$hex3 = substr($hex, -18, 2) . substr($hex, -20, 2);
$hex4 = substr($hex, -16, 4);
$hex5 = substr($hex, -12, 12);
$guid_str = $hex1 . "-" . $hex2 . "-" . $hex3 . "-" . $hex4 . "-" . $hex5;
return $guid_str;
}

Stav (2011-04-21 05:38:31)

I had a lot of issues with decoding errors using ldap_get_values_len() and found a of unanswered calls for help on a lot of forums.

The error message is - Warning: ldap_get_values(): Cannot get the value(s) of attribute Decoding error in xxx.php.

It appears that this error seems to cover a multitude sins including simple typos in the attribute name.

After using PHP to list the attributes of a particular record I noticed that the attribute userCertificate wasn't listed simply as userCertificate but userCertificate;binary instead.  I wrote this into my code and all was fixed.

So my code looks as follows.

<?php
        if (!$val = @ldap_get_values_len($con, $entry, "$attribute;binary"))
                die ('Error retrieving value (' . ldap_error($con) . ')');
?>

I hope this saves someone the pain I went through trawling Google for an answer.

jhgustafsson at gmail dot com (2009-06-02 03:07:35)

Tried a couple of different ways to do this but this seems to work best:

<?php
$info = ldap_first_entry($ds,$sr);

// get it binary-safe.
$bin_guid = ldap_get_values_len($ds,$info,"objectguid");

// convert to hex, bin2hex failed here for me. Unpack() seems to work though.
$hex_guid = unpack("H*hex", $bin_guid[0]);
?>

alexey_baranov at inbox dot ru (2009-04-02 04:26:27)

no more need to use ldap_get_values_len (). ldap_get_attributes() works well now.

<?php
$attrs = ldap_get_attributes($this->cid, $this->re);
$hex_Sid= bin2hex($attrs['objectSid'][0]); //returns 010500000000000515000000c94d7d363d787b17e77b80109d060000
$hex_GUID= bin2hex($attrs['objectGUID'][0]); //returns 710234bbc2abc148ade8c1f9b4567b24
?>

etienne at i-james dot com (2007-08-23 02:40:26)

In order to set directory/file permissions with smbcacls, you'll need to get the objectSid and objectGuid, convert them with the functions described in the other post of this manual and concat them like this :
$user='S-' . $strObjectSid . '-' . $strObjectGuid

derek dot ethier at gmail dot com (2007-03-07 11:25:06)

One more function to add that complements the bin_to_str_guid function I posted below:
// This function will convert a string GUID value into a HEX value to search AD.
function str_to_hex_guid($str_guid) {
$str_guid = str_replace('-', '', $str_guid);
$octet_str = substr($str_guid, 6, 2);
$octet_str .= substr($str_guid, 4, 2);
$octet_str .= substr($str_guid, 2, 2);
$octet_str .= substr($str_guid, 0, 2);
$octet_str .= substr($str_guid, 10, 2);
$octet_str .= substr($str_guid, 8, 2);
$octet_str .= substr($str_guid, 14, 2);
$octet_str .= substr($str_guid, 12, 2);
$octet_str .= substr($str_guid, 16, strlen($str_guid));
return $octet_str;
}
If you want to convert the string GUID back to the HEX format (required if you want to search AD based on the GUID string, make sure you escape the HEX string with double backslashes when searching -- ie. \\AE\\0F\\88...).

derek dot ethier at gmail dot com (2007-02-12 19:49:49)

To elaborate on rcrow's post, if you want to convert the objectSID value to a usable string (from Active Directory) the following function will do the trick (this was borrowed from another section of the manual, just thought I'd add it here):
// Returns the textual SID
function bin_to_str_sid($binsid) {
$hex_sid = bin2hex($binsid);
$rev = hexdec(substr($hex_sid, 0, 2));
$subcount = hexdec(substr($hex_sid, 2, 2));
$auth = hexdec(substr($hex_sid, 4, 12));
$result = "$rev-$auth";
for ($x=0;$x < $subcount; $x++) {
$subauth[$x] =
hexdec($this->little_endian(substr($hex_sid, 16 + ($x * 8), 8)));
$result .= "-" . $subauth[$x];
}
// Cheat by tacking on the S-
return 'S-' . $result;
}
// Converts a little-endian hex-number to one, that 'hexdec' can convert
function little_endian($hex) {
for ($x = strlen($hex) - 2; $x >= 0; $x = $x - 2) {
$result .= substr($hex, $x, 2);
}
return $result;
}
This function is not related to the ldap_get_values_len function but is still helpful if you want to convert the objectGUID binary value to a string format (converted from some vbscript provided by Richard Mueller):
// This function will convert a binary value guid into a valid string.
function bin_to_str_guid($object_guid) {
$hex_guid = bin2hex($object_guid);
$hex_guid_to_guid_str = '';
for($k = 1; $k <= 4; ++$k) {
$hex_guid_to_guid_str .= substr($hex_guid, 8 - 2 * $k, 2);
}
$hex_guid_to_guid_str .= '-';
for($k = 1; $k <= 2; ++$k) {
$hex_guid_to_guid_str .= substr($hex_guid, 12 - 2 * $k, 2);
}
$hex_guid_to_guid_str .= '-';
for($k = 1; $k <= 2; ++$k) {
$hex_guid_to_guid_str .= substr($hex_guid, 16 - 2 * $k, 2);
}
$hex_guid_to_guid_str .= '-' . substr($hex_guid, 16, 4);
$hex_guid_to_guid_str .= '-' . substr($hex_guid, 20);
return strtoupper($hex_guid_to_guid_str);
}
Here's an example on how to use both:
$filter="samaccountname=".$username;
$fields=array("objectguid","objectsid");
//establish the connection and specify the base_dn first. there are a lot of examples in the manual for this
$sr=ldap_search($this->_conn,$this->_base_dn,$filter,$fields);
$entries = ldap_get_entries($this->_conn, $sr);
if (in_array("objectguid", $fields)) {
$entries[0]["objectguid"][0]=
$this->bin_to_str_guid($entries[0]["objectguid"][0]);
}
if (in_array("objectsid", $fields)) {
$entry = ldap_first_entry($this->_conn, $sr);
$objectsid_binary = ldap_get_values_len($this->_conn, $entry, "objectsid");
$entries[0]["objectsid"][0] = $this->bin_to_str_sid($objectsid_binary[0]);
}
Hope this helps someone!

rcrow at NOSPAM dot laptv dot com (2004-04-29 17:06:26)

If you are trying to access BINARY DATA, such as ObjectSID within LDAP, you must first get an individual entry, as stated under ldap_get_values() function -- "This call needs a result_entry_identifier, so needs to be preceded by one of the ldap search calls and one of the calls to get an individual entry."

The following code snippet will get the LDAP objectSID for a specific user.

<?php
/* Get the binary objectsid entry                                           */
/* Be sure that you have included the binary field in your ldap_search.    */
$criteria =  "samaccountname=$ldapUser";
$justthese = array("memberOf", "objectsid");
    
$ldapSearchResult = ldap_search($ldapConnectionResult, $ldapBase, $criteria, $justthese);
  
if (ldap_count_entries($ldapConnectionResult, $ldapSearchResult)){
     $ldapResults = ldap_get_entries($ldapConnectionResult, $ldapSearchResult);

   $entry = ldap_first_entry($ldapConnectionResult, $ldapSearchResult);
   $ldapBinary = ldap_get_values_len ($ldapConnectionResult, $entry, "objectsid");

/* your code here */
  
}
?>

You then can use something like bin2hex to put the data in a more usable form.