Q: cert authentication and user remapping fails

Albrecht Dreß <[email protected]> Fri, 06 Dec 2019 18:22:18 +0100

Newsgroups	gmane.comp.db.postgresql.general
Message-ID	<[email protected]>

Hi all,

I have a problem with psql cert authentication and user mapping.

In my installation, the user certificate CN's contain human-readable names (utf8, with spaces, etc.).  I want *all* users connecting with cert authentication to be mapped to a certain database role.  The server runs on Debian Stretch, using the package “postgresql-10” ver. “10.11-1.pgdg90+1”.

The configuration in pg_hba.conf is, inter alia

<snip>
hostssl	testdb	all	172.16.61.0/24	cert map=certaccess
</snip>

The file pg_ident.conf contains the line (which should, as the re matches *everything*, map all users?)

<snip>
certaccess	/^.*$	testuser
</snip>

I have a user certificate, issued by the same CA as the server cert, with CN "Albrecht Dreß".  Running psql on a remote client fails:

<snip>
albrecht@deneb:~$ psql -h dbserver -U "Albrecht Dreß" testdb
psql: FATAL:  certificate authentication failed for user "Albrecht Dreß"
FATAL:  no pg_hba.conf entry for host "172.16.61.70", user "Albrecht Dreß", database "testdb", SSL off
</snip>

The server log says:

<snip>
Albrecht Dreß@testdb LOG:  no match in usermap "certaccess" for user "Albrecht Dreß" authenticated as "Albrecht Dreß"
Albrecht Dreß@testdb FATAL:  certificate authentication failed for user "Albrecht Dreß"
Albrecht Dreß@testdb DETAIL:  Connection matched pg_hba.conf line 136: "  hostssl    testdb    all             172.16.61.0/24     cert map=certaccess"
Albrecht Dreß@testdb FATAL:  no pg_hba.conf entry for host "172.16.61.70", user "Albrecht Dreß", database "testdb", SSL off
</snip>

For me, this looks as if the certificate is accepted, but the regexp match of the CN somehow fails.

Note 1: I don't have a role “Albrecht Dreß” defined.
Note 2: using my “real” user name (albrecht), i.e. omitting the “-U” option above, fails with the server log message “provided user name (albrecht) and authenticated user name (Albrecht Dreß) do not match”.

Any idea what I did wrong, and how I can a working cert authentication?

Thanks in advance,
Albrecht.

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