[Freeipa-devel] [PATCH] 0207, 0218-0219 Solving trust conflicts and external trust topology fixes

[Martin Babinsky]

On 08/15/2016 06:06 PM, Alexander Bokovoy wrote:
> On Mon, 15 Aug 2016, Alexander Bokovoy wrote:
>> Hi!
>>
>> Attached are trust-related patches.
>>
>> 0207 is a pre-requisite. I did send it before, it is re-formatting of
>> the ipaserver/dcerpc.py to be close to PEP8 requirements.
>>
>> 0218 is an automated trust topology conflict resolver for DNS namespace
>> conflicts. Read the commit message for details, and also comments in the
>> code. With this patch FreeIPA becomes more smart than Windows Server
>> which doesn't have automated trust topology conflict resolution. ;)
>>
>> 0219 fixes issue of topology details leaking through external trust. The
>> problem is only in presentation as we store more data than needed -- it
>> is impossible to cross external trust boundary anyway as it is handled
>> by AD DC side, but one important consequence is that we need to store
>> UPN suffixes before we start storing information about child domains.
>> Again, read the commit message.
>>
>> These patches also are on top of my previously sent patches 0215-0216.
> Patches attached.
>
>
>

Hi Alexander,

patch 207: LGTM, but I have a feeling that the patch should be linked to 
both #6021 and #6076 so that it is not lost during backports.

patch 218:

ipalib/errors.py:

1.)
I'm not sure if TrustTopologyConflictError should inherit from 
InvocationError. The semantics of InvocationError implies that something 
was wrong when trying to invoke the command (a param failed to 
validate/convert, incorrect number of args, etc.), while this is more of 
an exception during command execution (no. and type of params was 
correct, command started to execute but encountered an error condition). 
Thus I think it should inherit from ExecutionError. CC'ing Jan for more 
thoughts on this.

2.)

Why is TrustTopologyConflictSolved listed amogn public errors? Since it 
is used only in dcerpc.py to restart trust establishment after resolving 
conflicts, it should be a private exception in dcerpc.py for this purpose.

3.)
Also please split the exception format string like this so that the line 
is not too long (there is not much we can do about doctest so leave that 
line as it is):

@@ -882,7 +882,8 @@ class TrustTopologyConflictError(InvocationError):
      """

      errno = 3017
-    format = _("Forest '%(forest)s' has existing trust to forest(s) 
%(domains)s which prevents a trust to '%(conflict)s'")
+    format = _("Forest '%(forest)s' has existing trust to forest(s) "
+               "%(domains)s which prevents a trust to '%(conflict)s'")

Do not worry about gettext, it can handle it just fine, there are plenty 
of examples in server plugins, for example.


ipaserver/dcerpc.py:

1.)

I think that instead of returning result and raising 
TrustTopologyConflictError based on that, the 'clear_ftinfo_conflict' 
can raise this exception directly. You can have an empty list defined at 
the beginning instead of 'result list', append unresolvable conflicts to 
it and then at the end of the method check if it is non-empty and raise 
the exception.

2.)

+        # In the code below:
+        # self -- the forest we establish trust to
+        # another_domain -- a forest that establishes trust to 'self'
+        # cinfo -- lsa_ForestTrustCollisionInfo structure that contain
+        #          set of of lsa_ForestTrustCollisionRecord structures
I would add this directly into the method docstring:

"""
...

:param self: the forest we establish trust to
:param another_domain: a forest that establishes trust to 'self'
:param cinfo: lsa_ForestTrustCollisionInfo structure that contain
	      set of of lsa_ForestTrustCollisionRecord structures
"""

Additionally, the behavior specifed in previous comment can be added 
using :raises: stanza:

"""
:raises: errors.TrustTopologyConflictError if there are unresolvable
     namespace conflicts between trusted domains
"""

3.)

rewriting 'clear_ftinfo_conflict' according to point 1.) will allow to 
simplify code in 'update_ftinfo' like this:

"""
-                res = self.clear_ftinfo_conflict(another_domain, cinfo)
-                if len(res[1]) != 0:
-                    domains = [x.name.string for x in res[1]]
-                    raise errors.TrustTopologyConflictError(
-                              target=self.info['dns_domain'],
-                              conflict=another_domain.info['dns_domain'],
-                              domains=domains)
-                else:
-                    raise errors.TrustTopologyConflictSolved(
-                              target=self.info['dns_domain'],
-                              conflict=another_domain.info['dns_domain'])
+                self.clear_ftinfo_conflict(another_domain, cinfo)
+                raise errors.TrustTopologyConflictSolved(
+                    target=self.info['dns_domain'],
+                    conflict=another_domain.info['dns_domain'])
"""

Patch 218:

1.)
typo in the commit message:

"""
...
suffixes are forest-wide, there *are could be* user accounts in the
...
"""

2.)
A stupid question I know, but why do we need to replace empty string 
with None here?

"""
          # with the forest, thus we have to use 
netr_DsRGetForestTrustInformation
-        domains = 
netr_pipe.netr_DsRGetForestTrustInformation(td.info['dc'], '', 0)
+        domains = 
netr_pipe.netr_DsRGetForestTrustInformation(td.info['dc'], None, 0)
"""

-- 
Martin^3 Babinsky