[PATCH] passdb: handle UPN in lookup_name correctly

[Rowland Penny]

On Fri, 15 Feb 2019 17:06:04 +0100
Ralph Wuerthner via samba-technical <samba-technical at lists.samba.org>
wrote:

> On 13.02.19 16:18, Andreas Schneider wrote:
> > On Tuesday, February 12, 2019 1:38:09 PM CET Ralph Wuerthner via
> > samba- technical wrote:
> >> Hi Andreas!
> >>
> >> On 12.02.19 10:39, Andreas Schneider wrote:
> >>> On Monday, February 11, 2019 5:39:33 PM CET Ralph Wuerthner wrote:
> >>>> Hi Andreas!
> >>>>
> >>>> On 11.02.19 16:07, Andreas Schneider wrote:
> >>>>> Hi Ralph,
> >>>>>
> >>>>>> Please see attached patchset:
> >>>>>> The fix for Samba bugzilla 13312 (commit 1775ac8aa4) caused a
> >>>>>> regression
> >>>>>> when looking up names in UPN notation: Because
> >>>>>> winbind_lookup_name is called with lp_workgroup as domain name
> >>>>>> the lookup is now failing and the SID for an unmapped Unix
> >>>>>> user is returned by lookup_name. Fixed by calling
> >>>>>> winbind_lookup_name with an empty domain name in case the name
> >>>>>> is in UPN notation.
> >>>>>>
> >>>>>> The patchset already passed a CI run:
> >>>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__gitlab.com_samba-2Dteam_devel_samba_pipelines_46689980&d=DwICAg&c=jf_iaSHvJObTbx-siA1ZOg&r=91G8BCIr_Gua7QkxI_O-dlz8T-mXwIVnjFb7EjeIK7M&m=cE08ROyNiXvMje49eaTVj5qguLqqeNc9L0waXJZlLU8&s=HzsOgBRt8y3O1Jco7WX-FCBZUY8W7L24Vwu5jmYeGP8&e=
> >>>>>
> >>>>> Thanks for your contribution!
> >>>>>
> >>>>> Please use DGB_DEBUG() instead of DEBUG(10, ...)
> >>>>>
> >>>>> In lookup_upn() use a helper variable 'bool ok'. And check
> >>>>> talloc_strdup()
> >>>>> for NULL.
> >>>>
> >>>> Thanks for your feedback! I prepared a new version of the
> >>>> patchset with the following changes:
> >>>> - using a helper variable in lookup_upn()
> >>>> - use DBG_DEBUG() instead of DEBUG(10, ...)
> >>>>
> >>>> I didn't add a NULL check for talloc_strdup() because there is
> >>>> already a NULL check right after the ok: label. This check is
> >>>> used by other sequence steps in lookup_name() too.
> >>>
> >>> But then the function would need documentation that the caller is
> >>> responsible for the NULL check.
> >>>
> >>> I think this is strange code and we should do the check in place
> >>> and not defer it to later.
> >>
> >> Ahh, I got your point. I thought you were referring to the
> >> talloc_strdup() call from patch #2 in lookup_name(), instead you
> >> are referring to the talloc_strdup() call in lookup_upn(). You are
> >> right, there should be a check in lookup_upn(). I didn't pay much
> >> attention to this because patch #3 is elimination the
> >> talloc_strdup() call in lookup_upn(). Please see the attached
> >> patchset with the missing check (though it will be gone after
> >> applying patch #3).
> > 
> > This looks good. Now we need tests which verify this :-)
> 
> This will be the harder part...
> 
> I tried to recreate this in the ad_member test environment but
> without success. Samba's AD DC seems to behave slightly different
> than a Windows AD server. With or without my patchset I get the same
> results:
> 
> ./bin/rpcclient 127.0.0.29 -U% -c 'lookupnames "alice at ADDOMAIN"'
> alice at ADDOMAIN S-1-5-21-2858285458-1632643436-2480850723-1106 (User:
> 1)
> 
> But when doing this on my test system (without my patchset) I get a
> Unix SID when querying a Samba AD member:
> 
> rpcclient localhost -U'virtual1\administrator%*****' -c 'lookupnames 
> "testuser1 at virtual1.com"'
> testuser1 at virtual1.com S-1-22-1-12001118 (User: 1)
> 
> and the expected SID when querying the AD server directly:
> 
> rpcclient 10.0.100.8 -U'virtual1\administrator%*****' -c 'lookupnames 
> "testuser1 at virtual1.com"'
> testuser1 at virtual1.com S-1-5-21-3478218634-1770281059-659661689-1118 
> (User: 1)
> 
> Do we have to change the behavior of the Samba AD DC or what's the
> way forward here?
> 
> 

Could there be something wrong with your test system:

rowland at devstation:~$ rpcclient localhost -U'samdom\administrator%xxxxxxxxxx' -c 'lookupnames "rowland at samdom.example.com"'
rowland at samdom.example.com S-1-5-21-1768301897-3342589593-1064908849-1107 (User: 1)
rowland at devstation:~$ rpcclient 192.168.0.6 -U'samdom\administrator%xxxxxxxxxx' -c 'lookupnames "rowland at samdom.example.com"'
rowland at samdom.example.com S-1-5-21-1768301897-3342589593-1064908849-1107 (User: 1)

devstation is a Unix domain member
192.168.0.6 is a Samba AD DC

Rowland