V-72865

control "V-72865" do
  # @todo update the title of this control to something sane
    title "The role(s)/group(s) used to modify database structure (including but
          not necessarily limited to tables, indexes, storage, etc.) and logic
          modules (functions, trigger procedures, links to software external to
          PostgreSQL, etc.) must be restricted to authorized users."
    desc  "If PostgreSQL were to allow any user to make changes to database
          structure or logic, those changes might be implemented without
          undergoing the appropriate testing and approvals that are part of a
          robust change management process.

          Accordingly, only qualified and authorized individuals must be allowed
          to obtain access to information system components for purposes of
          initiating changes, including upgrades and modifications.

          Unmanaged changes that occur to the database software libraries or
          configuration can lead to unauthorized or compromised installations."
    impact 0.5
    tag "severity": "medium"
    tag "gtitle": "SRG-APP-000133-DB-000362"
    tag "gid": "V-72865"
    tag "rid": "SV-87517r1_rule"
    tag "stig_id": "PGS9-00-001300"
    tag "cci": "CCI-001499"
    tag "nist": ["CM-5 (6)", "Rev_4"]
    tag "check": "Note: The following instructions use the PGDATA environment
                  variable. See supplementary content APPENDIX-F for instructions
                  on configuring PGDATA.

                  As the database administrator (shown here as \"postgres\"),
                  list all users and their permissions by running the following
                  SQL:

                  $ sudo su - postgres
                  $ psql -c \"\\dp *.*\"

                  Verify that all objects have the correct privileges. If they do
                  not, this is a finding.

                  Next, as the database administrator (shown here as \"postgres\"),
                  verify the permissions of the database directory on the
                  filesystem:

                  $ ls -la ${PGDATA?}

                  If permissions of the database directory are not limited to an
                  authorized user account, this is a finding."

    tag "fix": "As the database administrator, revoke any permissions from a role
                that are deemed unnecessary by running the following SQL:

                ALTER ROLE bob NOCREATEDB;
                ALTER ROLE bob NOCREATEROLE;
                ALTER ROLE bob NOSUPERUSER;
                ALTER ROLE bob NOINHERIT;
                REVOKE SELECT ON some_function FROM bob;"

  exceptions = "#{PG_OBJECT_EXCEPTIONS.map { |e| "'#{e}'" }.join(',')}"
  sql = postgres_session(PG_DBA, PG_DBA_PASSWORD, PG_HOST)

  binding_users = []
  if not PG_BINDINGS_DB.empty? and not PG_BINDING_USERS_SQL.empty?
    binding_users_query = sql.query(PG_BINDING_USERS_SQL, [PG_BINDINGS_DB])
    binding_users = binding_users_query.lines
  end

  authorized_owners = PG_OBJECT_OWNERS + binding_users
  owners = authorized_owners.join('|')
  superusers = PG_SUPERUSERS.join('|')

  databases_sql = 'SELECT datname FROM pg_catalog.pg_database;'
  databases_query = sql.query(databases_sql, [PG_DB])
  databases = databases_query.lines

  databases.each do |database|
    role_list = database == 'postgres' ? superusers : owners
    object_acl = "^((((#{role_list})=[#{PG_OBJECT_GRANTED_PRIVILEGES}]+|"\
      "=[#{PG_OBJECT_PUBLIC_PRIVILEGES}]+)\\/\\w+,?)+|)$"
    objects_sql = "SELECT n.nspname, c.relname, c.relkind, "\
      "pg_catalog.array_to_string(c.relacl, E',') "\
      "FROM pg_catalog.pg_class c "\
      "LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace "\
      "WHERE c.relkind IN ('r', 'v', 'm', 'S', 'f') "\
      "AND n.nspname !~ '^pg_' AND pg_catalog.pg_table_is_visible(c.oid) "\
      "AND pg_catalog.array_to_string(c.relacl, E',') !~ '#{object_acl}' "\
      "AND c.relname NOT IN (#{exceptions});"

    connection_error = "FATAL:\\s+database \"#{database}\" is not currently "\
      "accepting connections"
    connection_error_regex = Regexp.new(connection_error)

    describe.one do
      describe sql.query(objects_sql, [database]) do
        its('output') { should eq '' }
      end

      describe sql.query(objects_sql, [database]) do
        it { should match connection_error_regex }
      end
    end
    # TODO: Add test for column acl
  end

  describe directory(PG_DATA) do
    it { should be_directory }
    it { should be_owned_by PG_OWNER }
    its('mode') { should cmp '0700' }
  end
end