V-73055

control "V-73055" do
  title "PostgreSQL must map the PKI-authenticated identity to an associated user
account."
  desc  "The DoD standard for authentication is DoD-approved PKI certificates. Once
a PKI certificate has been validated, it must be mapped to PostgreSQL user account
for the authenticated identity to be meaningful to PostgreSQL and useful for
authorization decisions."
  impact 0.5
  tag "severity": "medium"
  tag "gtitle": "SRG-APP-000177-DB-000069"
  tag "gid": "V-73055"
  tag "rid": "SV-87707r1_rule"
  tag "stig_id": "PGS9-00-011800"
  tag "cci": "CCI-000187"
  tag "nist": ["IA-5 (2) (c)", "Rev_4"]
  tag "check": "The cn (Common Name) attribute of the certificate will be compared
to the requested database user name, and if they match the login will be allowed.

To check the cn of the certificate, using openssl, do the following:

$ openssl x509 -noout -subject -in client_cert

If the cn does not match the users listed in PostgreSQL and no user mapping is used,
this is a finding.

User name mapping can be used to allow cn to be different from the database user
name. If User Name Maps are used, run the following as the database administrator
(shown here as \"postgres\"), to get a list of maps used for authentication:

$ sudo su - postgres
$ grep \"map\" ${PGDATA?}/pg_hba.conf

With the names of the maps used, check those maps against the user name mappings in
pg_ident.conf:

$ sudo su - postgres
$ cat ${PGDATA?}/pg_ident.conf

If user accounts are not being mapped to authenticated identities, this is a finding.

If the cn and the username mapping do not match, this is a finding."
  tag "fix": "Configure PostgreSQL to map authenticated identities directly to
PostgreSQL user accounts.

For information on configuring PostgreSQL to use SSL, see supplementary content
APPENDIX-G."

  only_if { false }

end