|Summary:||mod_authnz_ldap denies users when search is performed at AD root.|
|Product:||Apache httpd-2||Reporter:||Tom McLaughlin <tmclaugh>|
|Component:||mod_authz_ldap||Assignee:||Apache HTTPD Bugs Mailing List <bugs>|
Description Tom McLaughlin 2010-07-21 15:03:56 UTC
When mod_authnz_ldap is setup to search for a user at the root of an AD domain it will fail the user because of the referrals returned in the search. --- config --- <Location /private> # SSLRequireSSL AuthType Kerberos AuthName "EXAMPLE Domain Login" KrbMethodNegotiate On KrbMethodK5Passwd On KrbAuthRealms EXAMPLE.COM Krb5KeyTab /etc/httpd/conf/keytab require valid-user # Strip the realm from the kerberos principle. MapUsernameRule (.*)@(.*) "$1" AuthLDAPURL "ldap://dc1.example.com dc2.example.com/dc=example,dc=com?sAMAccountName" AuthLDAPBindDN cn=nss_ldap,ou=services,dc=example,dc=com AuthLDAPBindPassword ******** Require ldap-group cn=Domain Admins,ou=Groups,dc=example,dc=com </Location> --- --- error_log --- [Wed Jul 21 14:40:34 2010] [debug] src/mod_auth_kerb.c(1432): [client 172.30.235.107] kerb_authenticate_user entered with user (NULL) and auth_type Kerberos [Wed Jul 21 14:40:34 2010] [debug] src/mod_auth_kerb.c(915): [client 172.30.235.107] Using HTTP/corptech.meditech.com@MEDITECH.COM as server principal for password verification [Wed Jul 21 14:40:34 2010] [debug] src/mod_auth_kerb.c(655): [client 172.30.235.107] Trying to get TGT for user tmclaughlin@MEDITECH.COM [Wed Jul 21 14:40:34 2010] [debug] src/mod_auth_kerb.c(569): [client 172.30.235.107] Trying to verify authenticity of KDC using principal HTTP/corptech.meditech.com@MEDITECH.COM [Wed Jul 21 14:40:34 2010] [debug] src/mod_auth_kerb.c(994): [client 172.30.235.107] kerb_authenticate_user_krb5pwd ret=0 user=tmclaughlin@MEDITECH.COM authtype=Basic [Wed Jul 21 14:40:34 2010] [info] [client 172.30.235.107] Applying pattern '^(.*)@(.*)$' to user 'tmclaughlin@MEDITECH.COM', mech:'Any' [Wed Jul 21 14:40:34 2010] [info] [client 172.30.235.107] Pattern matched [Wed Jul 21 14:40:34 2010] [notice] [client 172.30.235.107] User name 'tmclaughlin@MEDITECH.COM' rewritten to 'tmclaughlin' [Wed Jul 21 14:40:34 2010] [debug] mod_authnz_ldap.c(683): [client 172.30.235.107] ldap authorize: Creating LDAP req structure [Wed Jul 21 14:40:37 2010] [debug] mod_authnz_ldap.c(695): [client 172.30.235.107] auth_ldap authorise: User DN not found, ldap_search_ext_s() for user failed --- The resulting request made by mod_authnz_ldap is for (&(objectclass=*)(sAMAccountName=tmclaughlin)). The search result is the account entry in AD plus three referrals: ldap://DomainDnsZones.example.com/DC=DomainDnsZones,DC=example,DC=com ldap://ForestDnsZones.example.com/DC=ForestDnsZones,DC=example,DC=com ldap://example.com/CN=Configuration,DC=example,DC=com The attempts to search these three referrals all fail with the same LDAP error: 00000000: LdapErr: DSID-0C090627, comment: In order to perform this operation a successful bind must be completed on the connection., data 0, vece I've found two workarounds for this issue. One is to change the path in AuthLDAPURL to where all our users are stored. This may not work for all organizations. The second is to set in /etc/openldap/ldap.conf "REFERRALS off". That unfortunately affects the behavior of everything using the openldap libs. The best fix would probably be to implement what looks to have been done in mod_auth_ldap in bugzilla 26538 and add AuthLDAPFollowReferrals which would allow toggling referral chasing in mod_authnz_ldap.
Comment 1 Eric Covener 2010-07-21 15:57:15 UTC
other options: point at the global catalog port, or to the "ADAM" frontend.
Comment 2 Tom McLaughlin 2010-07-21 17:42:03 UTC
Only problem I could see with searching a global catalog is often times the GC servers are a subset of your DCs. You may have multiple DCs per site with only one GC in that site. From my recollection of AD topology recommendations that is an advisable setup according to MS. (It's to balance availability with replication load.) For redundancy with mod_authnz_ldap you would end up pointing to the local site GC and a foreign site's GC instead of just utilizing the local site DCs. ref: http://technet.microsoft.com/en-us/library/cc978012.aspx http://technet.microsoft.com/en-us/library/cc728188%28WS.10%29.aspx
Comment 3 Eric Covener 2014-01-19 20:29:43 UTC
referral stuff in 2.4 helpful for this? (sorry this PR has been stagnant)
Comment 4 William A. Rowe Jr. 2018-11-07 21:08:50 UTC
Please help us to refine our list of open and current defects; this is a mass update of old and inactive Bugzilla reports which reflect user error, already resolved defects, and still-existing defects in httpd. As repeatedly announced, the Apache HTTP Server Project has discontinued all development and patch review of the 2.2.x series of releases. The final release 2.2.34 was published in July 2017, and no further evaluation of bug reports or security risks will be considered or published for 2.2.x releases. All reports older than 2.4.x have been updated to status RESOLVED/LATER; no further action is expected unless the report still applies to a current version of httpd. If your report represented a question or confusion about how to use an httpd feature, an unexpected server behavior, problems building or installing httpd, or working with an external component (a third party module, browser etc.) we ask you to start by bringing your question to the User Support and Discussion mailing list, see [https://httpd.apache.org/lists.html#http-users] for details. Include a link to this Bugzilla report for completeness with your question. If your report was clearly a defect in httpd or a feature request, we ask that you retest using a modern httpd release (2.4.33 or later) released in the past year. If it can be reproduced, please reopen this bug and change the Version field above to the httpd version you have reconfirmed with. Your help in identifying defects or enhancements still applicable to the current httpd server software release is greatly appreciated.