[Freeipa-devel] [PATCH 0215-0216] Child domain fixes for AD trust

Alexander Bokovoy abokovoy at redhat.com
Mon Aug 8 11:27:22 UTC 2016


Hi!

Attached two patches attempt to fix some of the issues we see with child
domains.

SSSD only 'sees' users from child domains if there is an ID range for
each of them. However, after refactoring of trust code when external
trust was introduced, part of the range creation had wrong assumption
that if a trusted domain exists, its range also exists. This is now
fixed to try to create range even if the domain exists. In fact, because
the older code was not going to the range creation for trusted domains
which already existed, adding ranges was done incorrectly: ID ranges use
full domain name and don't need <parent>-<child> hierarchy, but the code
was passing both parent and the child names. As result, an attempt to
create an ID range for parent was done instead of the child. Parent ID
range already existed so we never got to create child ID ranges at all
in that case.

Finally, there is a fix in SSSD to properly generate CA paths so that
libkrb5 can calculate correct trust path via forest root (parent)
domain. While looking at that, I also decided to simplify logic in
ipa-kdb driver because for cross-forest trust we never can transit to
the child domain directly, we always have to use the forest root domain.
However, old code could actually set a immediate domain's parent instead
of the forest root for deep level trust relationship within the forest
we trust. As we still cannot get to second level or beyond directly or
via their actual parent domain, we always have to go through the forest
root domain. The simplified code enforces this logic.


-- 
/ Alexander Bokovoy
-------------- next part --------------
From 37e4ab4786aec94bfb057fa3146d4e18e30df391 Mon Sep 17 00:00:00 2001
From: Alexander Bokovoy <abokovoy at redhat.com>
Date: Sat, 6 Aug 2016 11:12:13 +0300
Subject: [PATCH 4/5] trust: make sure ID range is created for the child domain
 even if it exists

ID ranges for child domains of a forest trust were created incorrectly
in FreeIPA 4.4.0 due to refactoring of -- if the domain was already
existing, we never attempted to create the ID range for it.

At the same time, when domain was missing, we attempted to add ID range
and passed both forest root and the child domain names to add_range().
However, add_range() only looks at the first positional argument which
was the forest root name. That ID range always exists (it is created
before child domains are processed).

Modify the code to make sure child domain name is passed as the first
positional argument. In addition, the oddjob helper should explicitly
set context='server' so that idrange code will be able to see and use
ipaserver/dcerpc.py helpers.

Resolves: https://fedorahosted.org/freeipa/ticket/5738
---
 install/oddjob/com.redhat.idm.trust-fetch-domains |  2 +-
 ipaserver/plugins/trust.py                        | 10 +++++++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/install/oddjob/com.redhat.idm.trust-fetch-domains b/install/oddjob/com.redhat.idm.trust-fetch-domains
index 7c948fd..bffa021 100755
--- a/install/oddjob/com.redhat.idm.trust-fetch-domains
+++ b/install/oddjob/com.redhat.idm.trust-fetch-domains
@@ -76,7 +76,7 @@ env._bootstrap(debug=options.debug, log=None)
 env._finalize_core(**dict(DEFAULT_CONFIG))
 
 # Initialize the API with the proper debug level
-api.bootstrap(in_server=True, debug=env.debug, log=None)
+api.bootstrap(in_server=True, debug=env.debug, log=None, context='server')
 api.finalize()
 
 # Only import trust plugin after api is initialized or internal imports
diff --git a/ipaserver/plugins/trust.py b/ipaserver/plugins/trust.py
index f2e0b1e..f90d9c1 100644
--- a/ipaserver/plugins/trust.py
+++ b/ipaserver/plugins/trust.py
@@ -1673,15 +1673,19 @@ def add_new_domains_from_trust(myapi, trustinstance, trust_entry, domains, **opt
             if 'raw' in options:
                 dom['raw'] = options['raw']
 
-            res = myapi.Command.trustdomain_add(trust_name, name, **dom)
-            result.append(res['result'])
+            try:
+                res = myapi.Command.trustdomain_add(trust_name, name, **dom)
+                result.append(res['result'])
+            except errors.DuplicateEntry:
+                # Ignore updating duplicate entries
+                pass
 
             if idrange_type != u'ipa-ad-trust-posix':
                 range_name = name.upper() + '_id_range'
                 dom['range_type'] = u'ipa-ad-trust'
                 add_range(myapi, trustinstance,
                           range_name, dom['ipanttrusteddomainsid'],
-                          trust_name, name, **dom)
+                          name, **dom)
         except errors.DuplicateEntry:
             # Ignore updating duplicate entries
             pass
-- 
2.7.4

-------------- next part --------------
From 767458d1532feb7029ff9a52e67e931fd87869ec Mon Sep 17 00:00:00 2001
From: Alexander Bokovoy <abokovoy at redhat.com>
Date: Sun, 7 Aug 2016 21:42:14 +0300
Subject: [PATCH 5/5] ipa-kdb: simplify trusted domain parent search

In terms of cross-forest trust parent domain is the root domain of
the forest because we only have trust established with the forest root.

In FreeIPA LDAP store all sub-domains stored in cn=<forest root>,
cn=ad,cn=trusts,... subtree. Thus, a first RDN after cn=ad is the
forest root domain. This allows us to simplify logic of finding
the parent domain.

For complex hierachical forests with more than two levels of
sub-domains, this will still be true because of the forest trust:
as forest trust is established to the forest root domain, any
communication to any sub-domain must traverse forest root domain's
domain controller.

Note that SSSD also generated incorrectly CA paths information
for forests with non-hierarchical tree-roots. In such cases
IPA KDC got confused and mistakenly assumed direct trust to the
non-hierarchical tree-root instead of going through the forest
root domain. See https://fedorahosted.org/sssd/ticket/3103 for
details.

Resolves: https://fedorahosted.org/freeipa/ticket/5738
---
 daemons/ipa-kdb/ipa_kdb_mspac.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/daemons/ipa-kdb/ipa_kdb_mspac.c b/daemons/ipa-kdb/ipa_kdb_mspac.c
index 80e7055..76e9e99 100644
--- a/daemons/ipa-kdb/ipa_kdb_mspac.c
+++ b/daemons/ipa-kdb/ipa_kdb_mspac.c
@@ -2420,6 +2420,7 @@ krb5_error_code ipadb_mspac_get_trusted_domains(struct ipadb_context *ipactx)
     char *base = NULL;
     char *dnstr = NULL;
     char *dnl = NULL;
+    LDAPDN dn = NULL;
     char **sid_blacklist_incoming = NULL;
     char **sid_blacklist_outgoing = NULL;
     int ret, n, i;
@@ -2547,26 +2548,26 @@ krb5_error_code ipadb_mspac_get_trusted_domains(struct ipadb_context *ipactx)
             goto done;
         }
 
-        /* Note that after ldap_str2rdn() call dnl will point to end of one RDN
-         * which would be '\0' for trust root domain and ',' for subdomain */
         dnl--; dnl[0] = '\0';
-        ret = ldap_str2rdn(dnstr, &rdn, &dnl, LDAP_DN_FORMAT_LDAPV3);
+        /* Create a DN, which is now everything before the base,
+         * to get list of rdn values -- the last one would be a root domain.
+         * Since with cross-forest trust we have to route everything via root
+         * domain, that is enough for us to assign parentship. */
+        ret = ldap_str2dn(dnstr, &dn, LDAP_DN_FORMAT_LDAPV3);
         if (ret) {
             goto done;
         }
 
-        ldap_rdnfree(rdn);
-
-        if (dnl[0] != '\0') {
-            dnl++;
-            ret = ldap_str2rdn(dnl, &rdn, &dnl, LDAP_DN_FORMAT_LDAPV3);
-            if (ret) {
-                goto done;
-            }
-            t[n].parent_name = strndup(rdn[0]->la_value.bv_val, rdn[0]->la_value.bv_len);
-            ldap_rdnfree(rdn);
+        rdn = NULL;
+        for (i = 0; dn[i] != NULL; i++) {
+            rdn = dn[i];
         }
 
+        /* We should have a single AVA in the domain RDN */
+        t[n].parent_name = strndup(rdn[0]->la_value.bv_val, rdn[0]->la_value.bv_len);
+
+        ldap_dnfree(dn);
+
         free(dnstr);
         dnstr = NULL;
     }
-- 
2.7.4



More information about the Freeipa-devel mailing list