Re: [GENERAL] pg_ident mapping Kerberos Usernames

On 09/10/2017 02:39 AM, Magnus Hagander wrote:
> On Sat, Sep 9, 2017 at 6:44 PM, <techmail+pgsql@dangertoaster.com
> <mailto:techmail+pgsql@dangertoaster.com>> wrote:
>
>     Hi,
>
>     I'm trying to get pg_ident to map "user1" and "user1@A.DOMAIN.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@A.DOMAIN.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@a.domain.tld".
>
>
>     pg_hba.conf:
>
>     local   all             postgres                                peer
>     host    all             all 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>          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>:
>
>     /^([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@A.DOMAIN.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@A.DOMAIN.TLD > LOG: no match in usermap
>     "testnet" for user "user1@A.DOMAIN.TLD" authenticated as "user1@A.DOMAIN.TLD"
>     < 2017-09-09 19:50:55.023 CDT - 192.168.1.201 user1@A.DOMAIN.TLD > FATAL:  GSSAPI authentication
>     failed for user "user1@A.DOMAIN.TLD"
>     < 2017-09-09 19:50:55.023 CDT - 192.168.1.201 user1@A.DOMAIN.TLD > DETAIL:  Connection matched
>     pg_hba.conf line 87: "host   all
>              all 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/ <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@DOMAIN.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@A.DOMAIN.TLD -d user1


Works without map (provided I have a role created):

$ psql -h db0 -U user1@A.DOMAIN.TLD -d user1

Does not work without map:

$ psql -h db0     #Implied -U user1 -d user1
$ psql -h db0 -U user1 -d user1


I can get one style or the other to work, but I just can't get both to work a the same time.

If this is something that can't be done, I understand, but it looks like it should be possible per
the documentation.

Thanks,
Ryan


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