Re: pg_ident mapping Kerberos Usernames

On 09/10/2017 04:27 PM, Jeff Janes wrote:
> On Sun, Sep 10, 2017 at 11:25 AM, <techmail+pgsql(at)dangertoaster(dot)com
> <mailto:techmail+pgsql(at)dangertoaster(dot)com>> wrote:
>
> On 09/10/2017 02:39 AM, Magnus Hagander wrote:
>
> On Sat, Sep 9, 2017 at 6:44 PM, <techmail+pgsql(at)dangertoaster(dot)com
> <mailto:techmail%2Bpgsql(at)dangertoaster(dot)com> <mailto:techmail+pgsql(at)dangertoaster(dot)com
> <mailto:techmail%2Bpgsql(at)dangertoaster(dot)com>>> wrote:
>
> Hi,
>
> I'm trying to get pg_ident to map "user1" and "user1(at)A(dot)DOMAIN(dot)TLD" to "user1" in
> postgres, or
> vice versa. I'm not picky about which way works.
>
> Kerberos authentication works. I've gotten "user1" to login successfully with a
> Kerberos ticket,
> but I'm not able to get "user1(at)A(dot)DOMAIN(dot)TLD" to match.
>
> Environment:
> * PostgreSQL 9.6 from PostgreSQL repos
> * CentOS 7
> * FreeIPA for Kerberos, LDAP, etc.
> * Realm A.DOMAIN.TLD
> * "user1" database exists
> * "user1" role exists
> * Logging into CentOS usernames are configured to drop the domain, so they appear as
> "user1"
> rather then "user1(at)a(dot)domain(dot)tld".
>
>
> pg_hba.conf:
>
> local all postgres peer
> host all all 127.0.0.1/32 <http://127.0.0.1/32> <http://127.0.0.1/32>
> md5
> host all all ::1/128 md5
> host all all 192.168.1.0/24 <http://192.168.1.0/24>
> <http://192.168.1.0/24> gss include_realm=1
> map=testnet krb_realm=A.DOMAIN.TLD #This is on one line. Thunderbird is truncating lines.
>
>
> pg_ident.conf:
>
> testnet /^([0-9A-Za-z_-]+)@A\.DOMAIN\.TLD$ \1
> testnet /^([0-9A-Za-z_-]+)$ \1
>
>
> Regex that works for both in regexr.com <http://regexr.com> <http://regexr.com>:
>
> /^([0-9A-Za-z-_]+)(@A\.DOMAIN\.TLD)?$/gm
>
>
> Command and lines from pg_log:
>
> $ psql -h db0 # Logged in as user1 with Kerberos ticket
>
> < 2017-09-09 19:50:49.376 CDT - 192.168.1.201 [unknown] > LOG: connection received:
> host=192.168.1.201 port=44918
> < 2017-09-09 19:50:49.398 CDT - 192.168.1.201 user1 > LOG: connection authorized:
> user=user1
> database=user1
> < 2017-09-09 19:50:50.912 CDT - 192.168.1.201 user1 > LOG: disconnection: session time:
> 0:00:01.537 user=user1 database=user1 host=192.168.1.201 port=44918
>
> $ psql -h db0 -U user1(at)A(dot)DOMAIN(dot)TLD # Logged in as user1 with Kerberos ticket
>
> < 2017-09-09 19:50:54.959 CDT - 192.168.1.201 [unknown] > LOG: connection received:
> host=192.168.1.201 port=44920
> < 2017-09-09 19:50:55.023 CDT - 192.168.1.201 user1(at)A(dot)DOMAIN(dot)TLD > LOG: no match in usermap
> "testnet" for user "user1(at)A(dot)DOMAIN(dot)TLD" authenticated as "user1(at)A(dot)DOMAIN(dot)TLD"
> < 2017-09-09 19:50:55.023 CDT - 192.168.1.201 user1(at)A(dot)DOMAIN(dot)TLD > FATAL: GSSAPI
> authentication
> failed for user "user1(at)A(dot)DOMAIN(dot)TLD"
> < 2017-09-09 19:50:55.023 CDT - 192.168.1.201 user1(at)A(dot)DOMAIN(dot)TLD > DETAIL: Connection
> matched
> pg_hba.conf line 87: "host all
> all 192.168.1.0/24 <http://192.168.1.0/24> <http://192.168.1.0/24>
> gss include_realm=1 map=testnet
> krb_realm=A.DOMAIN.TLD"
>
>
> Is this something that is possible, or is it something where I need to pick one way to
> do it?
>
>
> This looks like you are trying to connect with the actual username user1¡A.DOMAIN.TLD.
> pg_ident only sets what you are allowed to log in as, not what it will attempt.
>
> If you are using psql, you are probably doing something like "psql -h myserver". You need to
> add the user, so "psql -h myserver -U user1", to instruct it of which username to actually
> use for the login.
>
> --
> Magnus Hagander
> Me: https://www.hagander.net/ <http://www.hagander.net/>
> Work: https://www.redpill-linpro.com/ <https://www.redpill-linpro.com/>
> <http://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>>
>
>
> Hi Magnus,
>
> Yes, the system username is "user1", per the default ipa-client-install SSSD setup, and the map
> is working for that. Without the map, I have to specify the full Kerberos username,
> user(at)DOMAIN(dot)TLD, in the psql command.
>
> Works with map:
>
> $ psql -h db0 #Implied -U user1 -d user1
> $ psql -h db0 -U user1 -d user1
>
> Does not work with map:
>
> $ psql -h db0 -U user1(at)A(dot)DOMAIN(dot)TLD -d user1
>
>
> If you want that to work with the map, then you need to change the map to add the domain, rather
> than removing it, which is what you currently do.
>
> But it is hard to figure out what it is you actually want. You listed some cases that work and some
> that don't, but haven't said which ones you want to work and which you want not to work.
> (Presumably if you want **all** cases to work, you would just use 'trust' and be done with it.)
>
>

GSSAPI is the authentication mechanism of choice, and it's working fine.

Here is what I'm trying to accomplish.

'user1' == 'user1' and 'user1(at)A(dot)DOMAIN(dot)TLD' == 'user1'.

From reading the docs, this is done via the pg_ident.conf file, and from reading the logs, there is
a problem with my map.

Hmm... Interesting thought.
*testing*
It sort of works. Setting the maps below maps the users straight across. 'user1' == 'user1' and
'user1(at)A(dot)DOMAIN(dot)TLD' == 'user1(at)A(dot)DOMAIN(dot)TLD', so it's partially working.

pg_indent.conf:
testnet /^([0-9A-Za-z_-]+)@A\.DOMAIN\.TLD$ \1
testnet /^([0-9A-Za-z_-]+)@A\.DOMAIN\.TLD$ \1(at)A(dot)DOMAIN(dot)TLD

If it's not possible, that's fine. I'm just wondering if it can be done. I might be misunderstanding
the docs or expecting too much. I'm not quite sure which it is, but it does seem like this should be
possible.

Let me know if I can clear anything else up.

Ryan