I seem to be unable to use php to securely bind to Active Directory. Unencrypted connections work fine. Using other clients are able to securely bind, e.g. connecting using LDAPAdmin over SSL. What is the problem here? Is there some LDAP SSL module that I’m missing? How to securely bind to the server using php?
I noticed from phpinfo() that cURL has support for ldap/ldaps – what is a good example on utilizing this to perform secure bind in php? Is this a viable workaround?
phpinfo();
ldap
LDAP Support enabled
RCS Version $Id: ldap.c 293036 2010-01-03 09:23:27Z sebastian $
Total Links 0/unlimited
API Version 3001
Vendor Name OpenLDAP
Vendor Version 20421
SASL Support Enabled
Attempting to bind to an Active Directory server using PHP Version 5.3.2-1ubuntu4.7 from Ubuntu 10.04 repo
$username = 'user';
$password = 'passwd';
$account_suffix = '@example.com';
$hostnameSSL = 'ldaps://ldap.example.com:636';
$hostnameTLS = 'ldap.example.com';
$portTLS = 389;
ldap_set_option(NULL, LDAP_OPT_DEBUG_LEVEL, 7);
// Attempting fix from http://www.php.net/manual/en/ref.ldap.php#77553
putenv('LDAPTLS_REQCERT=never');
####################
# SSL bind attempt #
####################
// Attempting syntax from http://www.php.net/manual/en/function.ldap-bind.php#101445
$con = ldap_connect($hostnameSSL);
if (!is_resource($con)) trigger_error("Unable to connect to $hostnameSSL",E_USER_WARNING);
// Options from http://www.php.net/manual/en/ref.ldap.php#73191
if (!ldap_set_option($con, LDAP_OPT_PROTOCOL_VERSION, 3))
{
trigger_error("Failed to set LDAP Protocol version to 3, TLS not supported",E_USER_WARNING);
}
ldap_set_option($con, LDAP_OPT_REFERRALS, 0);
if (ldap_bind($con,$username . $account_suffix, $password)) die('All went well using SSL');
ldap_close($con);
####################
# TLS bind attempt #
####################
$con = ldap_connect($hostnameTLS,$portTLS);
ldap_set_option($con, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_set_option($con, LDAP_OPT_REFERRALS, 0);
$encrypted = (ldap_start_tls($con));
if ($encrypted) ldap_bind($con,$username . $account_suffix, $password); // Unecrypted works, but don't want logins sent in cleartext
ldap_close($con);
#####################
# SASL bind attempt #
#####################
$con = ldap_connect($hostnameTLS,$portTLS);
ldap_set_option($con, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_set_option($con, LDAP_OPT_REFERRALS, 0);
ldap_sasl_bind($con, NULL, $password, 'DIGEST-MD5', NULL, $username. $account_suffix);
ldap_close($con);
All of the above fails. Errors from log:
ldap_create
ldap_url_parse_ext(ldaps://ldap.example.com:636)
ldap_bind_s
ldap_simple_bind_s
ldap_sasl_bind_s
ldap_sasl_bind
ldap_send_initial_request
ldap_new_connection 1 1 0
ldap_int_open_connection
ldap_connect_to_host: TCP ldap.example.com:636
ldap_new_socket: 27
ldap_prepare_socket: 27
ldap_connect_to_host: Trying 1.1.1.1:636
ldap_pvt_connect: fd: 27 tm: -1 async: 0
ldap_open_defconn: successful
ldap_send_server_request
ldap_result ld 0x215380c0 msgid 1
wait4msg ld 0x215380c0 msgid 1 (infinite timeout)
wait4msg continue ld 0x215380c0 msgid 1 all 1
** ld 0x215380c0 Connections:
* host: ldap.example.com port: 636 (default)
refcnt: 2 status: Connected
last used: Thu Mar 10 11:15:53 2011
** ld 0x215380c0 Outstanding Requests:
* msgid 1, origid 1, status InProgress
outstanding referrals 0, parent count 0
ld 0x215380c0 request count 1 (abandoned 0)
** ld 0x215380c0 Response Queue:
Empty
ld 0x215380c0 response count 0
ldap_chkResponseList ld 0x215380c0 msgid 1 all 1
ldap_chkResponseList returns ld 0x215380c0 NULL
ldap_int_select
read1msg: ld 0x215380c0 msgid 1 all 1
ldap_err2string
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP Warning: ldap_bind() [<a href='function.ldap-bind'>function.ldap-bind</a>]: Unable to bind to server: Can't contact LDAP server in /..test.php on line 28
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP Stack trace:
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP 1. {main}() /..test.php:0
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP 2. ldap_bind() /..test.php:28
ldap_free_request (origid 1, msgid 1)
ldap_free_connection 1 1
ldap_free_connection: actually freed
ldap_create
ldap_err2string
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP Warning: ldap_start_tls() [<a href='function.ldap-start-tls'>function.ldap-start-tls</a>]: Unable to start TLS: Not Supported in /..test.php on line 37
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP Stack trace:
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP 1. {main}() /..test.php:0
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP 2. ldap_start_tls() /..test.php:37
ldap_create
ldap_sasl_interactive_bind_s: user selected: DIGEST-MD5
ldap_err2string
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP Warning: ldap_sasl_bind() [<a href='function.ldap-sasl-bind'>function.ldap-sasl-bind</a>]: Unable to bind to server: Not Supported in /..test.php on line 47
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP Stack trace:
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP 1. {main}() /..test.php:0
[Thu Mar 10 11:15:53 2011] [error] [client ::1] PHP 2. ldap_sasl_bind() /..test.php:47
Looking at ssl response:
>> openssl s_client -connect my.example.com:636 -prexit
(...)
SSL handshake has read 5732 bytes and written 443 bytes
---
New, TLSv1/SSLv3, Cipher is RC4-MD5
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
Protocol : TLSv1
Cipher : RC4-MD5
Session-ID: 111111111111111111111111
Session-ID-ctx:
Master-Key: AAAAAAAAAAAAAAAAAAAAA
Key-Arg : None
Start Time: 1299071105
Timeout : 300 (sec)
Verify return code: 20 (unable to get local issuer certificate)
Results from ‘strace php test.php’ :
write(2, " refcnt: 2 status: Connected\n", 31 refcnt: 2 status: Connected
) = 31
write(2, " last used: Tue Mar 15 10:59:19"..., 39 last used: Tue Mar 15 10:59:19 2011
) = 39
write(2, "\n", 1
) = 1
write(2, "** ld 0x954e0b8 Outstanding Requ"..., 38** ld 0x954e0b8 Outstanding Requests:
) = 38
write(2, " * msgid 1, origid 1, status In"..., 41 * msgid 1, origid 1, status InProgress
) = 41
write(2, " outstanding referrals 0, pare"..., 43 outstanding referrals 0, parent count 0
) = 43
write(2, " ld 0x954e0b8 request count 1 ("..., 45 ld 0x954e0b8 request count 1 (abandoned 0)
) = 45
write(2, "** ld 0x954e0b8 Response Queue:\n", 32** ld 0x954e0b8 Response Queue:
) = 32
write(2, " Empty\n", 9 Empty
) = 9
write(2, " ld 0x954e0b8 response count 0\n", 32 ld 0x954e0b8 response count 0
) = 32
write(2, "ldap_chkResponseList ld 0x954e0b"..., 48ldap_chkResponseList ld 0x954e0b8 msgid 1 all 1
) = 48
write(2, "ldap_chkResponseList returns ld "..., 47ldap_chkResponseList returns ld 0x954e0b8 NULL
) = 47
write(2, "ldap_int_select\n", 16ldap_int_select
) = 16
poll([{fd=3, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, -1) = 1 ([{fd=3, revents=POLLIN}])
write(2, "read1msg: ld 0x954e0b8 msgid 1 a"..., 37read1msg: ld 0x954e0b8 msgid 1 all 1
) = 37
read(3, "", 8) = 0
write(2, "ldap_err2string\n", 16ldap_err2string
) = 16
write(2, "PHP Warning: ldap_bind(): Unabl"..., 158PHP Warning: ldap_bind(): Unable to bind to server: Can't contact LDAP server in
And I do have the /etc/ldap.conf fix with ‘TLS_REQCERT never’ – even though this fix is for a different error, which gives a fairly clear error message.
As my code is working fine with CentOS, I conclude that the problem is not programming specific. I have not been able to get it running in my Ubuntu environment as of yet, but I assume this is a bug in my server software.