Return consistent expiration message for forms-based login

We need to inform users when a forms-based login fails due to the
password needing to be reset. Currently there is no way to distinguish
a reset case vs an incorrect password.

This will bind the user using a simple LDAP bind over ldapi (by default)
and if that is successful, check the expiration date against the current
time.

The UI portion of this that uses this message will come later.

https://fedorahosted.org/freeipa/ticket/2608

ipaserver/rpcserver.py

@@ -32,6 +32,8 @@ from ipalib.errors import PublicError, InternalError, CommandError, JSONError, C
 from ipalib.request import context, Connection, destroy_context
 from ipalib.rpc import xml_dumps, xml_loads
 from ipalib.util import make_repr, parse_time_duration
+from ipalib.dn import DN
+from ipaserver.plugins.ldap2 import ldap2
 from ipapython.compat import json
 from ipalib.session import session_mgr, AuthManager, get_ipa_ccache_name, load_ccache_data, bind_ipa_ccache, release_ipa_ccache, fmt_time, default_max_session_duration
 from ipalib.backend import Backend
@@ -45,6 +47,7 @@ import string
 import datetime
 from decimal import Decimal
 import urlparse
+import time
 
 HTTP_STATUS_SUCCESS = '200 Success'
 HTTP_STATUS_SERVER_ERROR = '500 Internal Server Error'
@@ -136,12 +139,14 @@ class HTTP_Status(plugable.Plugin):
         output = _internal_error_template % dict(message=escape(message))
         return [output]
 
-    def unauthorized(self, environ, start_response, message):
+    def unauthorized(self, environ, start_response, message, reason):
         """
         Return a 401 Unauthorized error.
         """
         status = '401 Unauthorized'
         response_headers = [('Content-Type', 'text/html; charset=utf-8')]
+        if reason:
+            response_headers.append(('X-IPA-Rejection-Reason', reason))
 
         self.info('%s: %s', status, message)
 
@@ -935,10 +940,42 @@ class login_password(Backend, KerberosSession, HTTP_Status):
 
         # Get the ccache we'll use and attempt to get credentials in it with user,password
         ipa_ccache_name = get_ipa_ccache_name()
+        reason = 'invalid-password'
         try:
             self.kinit(user, self.api.env.realm, password, ipa_ccache_name)
         except InvalidSessionPassword, e:
-            return self.unauthorized(environ, start_response, str(e))
+            # Ok, now why is this bad. Is the password simply bad or is the
+            # password expired?
+            try:
+                dn = str(DN(('uid', user),
+                            self.api.env.container_user,
+                            self.api.env.basedn))
+                conn = ldap2(shared_instance=False,
+                             ldap_uri=self.api.env.ldap_uri)
+                conn.connect(bind_dn=dn, bind_pw=password)
+
+                # password is ok, must be expired, lets double-check
+                (userdn, entry_attrs) = conn.get_entry(dn,
+                    ['krbpasswordexpiration'])
+                if 'krbpasswordexpiration' in entry_attrs:
+                    expiration = entry_attrs['krbpasswordexpiration'][0]
+                    try:
+                        exp = time.strptime(expiration, '%Y%m%d%H%M%SZ')
+                        if exp <= time.gmtime():
+                            reason = 'password-expired'
+                    except ValueError, v:
+                        self.error('Unable to convert %s to a time string'
+                            % expiration)
+
+            except Exception:
+                # It doesn't really matter how we got here but the user's
+                # password is not accepted or the user is unknown.
+                pass
+            finally:
+                if conn.isconnected():
+                    conn.destroy_connection()
+
+            return self.unauthorized(environ, start_response, str(e), reason)
 
         return self.finalize_kerberos_acquisition('login_password', ipa_ccache_name, environ, start_response)
 

tests/test_ipaserver/test_rpcserver.py

@@ -102,11 +102,12 @@ def test_unauthorized_error():
     s = StartResponse()
 
     assert_equal(
-        f.unauthorized(None, s, 'unauthorized'),
+        f.unauthorized(None, s, 'unauthorized', 'password-expired'),
         [t % dict(message='unauthorized')]
     )
     assert s.status == '401 Unauthorized'
-    assert s.headers == [('Content-Type', 'text/html; charset=utf-8')]
+    assert s.headers == [('Content-Type', 'text/html; charset=utf-8'),
+                         ('X-IPA-Rejection-Reason', 'password-expired')]
 
 
 def test_params_2_args_options():