IdM Server: list all Employees with matching Smart Card

Implement a new IPA command allowing to retrieve the list of users matching
the provided certificate.
The command is using SSSD Dbus interface, thus including users from IPA
domain and from trusted domains. This requires sssd-dbus package to be
installed on IPA server.

https://fedorahosted.org/freeipa/ticket/6646

Reviewed-By: David Kupka <dkupka@redhat.com>
Reviewed-By: Jan Cholasta <jcholast@redhat.com>

API.txt

@@ -824,6 +824,16 @@ option: Str('version?')
 output: Entry('result')
 output: Output('summary', type=[<type 'unicode'>, <type 'NoneType'>])
 output: PrimaryKey('value')
+command: certmap_match/1
+args: 1,3,4
+arg: Bytes('certificate', cli_name='certificate')
+option: Flag('all', autofill=True, cli_name='all', default=False)
+option: Flag('raw', autofill=True, cli_name='raw', default=False)
+option: Str('version?')
+output: Output('count', type=[<type 'int'>])
+output: ListOfEntries('result')
+output: Output('summary', type=[<type 'unicode'>, <type 'NoneType'>])
+output: Output('truncated', type=[<type 'bool'>])
 command: certmapconfig_mod/1
 args: 0,8,3
 option: Str('addattr*', cli_name='addattr')
@@ -6517,6 +6527,8 @@ default: cert_request/1
 default: cert_revoke/1
 default: cert_show/1
 default: cert_status/1
+default: certmap/1
+default: certmap_match/1
 default: certmapconfig/1
 default: certmapconfig_mod/1
 default: certmapconfig_show/1

freeipa.spec.in

@@ -284,6 +284,8 @@ Requires: gzip
 Requires: oddjob
 # Require 0.6.0 for the new delegation access control features
 Requires: gssproxy >= 0.6.0
+# Require 1.15.1 for the certificate identity mapping feature
+Requires: sssd-dbus >= 1.15.1
 
 Provides: %{alt_name}-server = %{version}
 Conflicts: %{alt_name}-server

ipaserver/plugins/certmap.py

@@ -17,9 +17,14 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import base64
+import dbus
 import six
 
-from ipalib import api, errors
+from ipalib import api, errors, x509
+from ipalib import Bytes
+from ipalib.crud import Search
+from ipalib.frontend import Object
 from ipalib.parameters import Bool, DNSNameParam, Flag, Int, Str
 from ipalib.plugable import Registry
 from .baseldap import (
@@ -33,6 +38,7 @@ from .baseldap import (
     pkey_to_value)
 from ipalib import _, ngettext
 from ipalib import output
+from ipaserver.plugins.service import validate_certificate
 
 
 if six.PY3:
@@ -389,3 +395,161 @@ class certmaprule_disable(LDAPQuery):
             result=True,
             value=pkey_to_value(cn, options),
         )
+
+
+DBUS_SSSD_NAME = 'org.freedesktop.sssd.infopipe'
+DBUS_PROPERTY_IF = 'org.freedesktop.DBus.Properties'
+DBUS_SSSD_USERS_PATH = '/org/freedesktop/sssd/infopipe/Users'
+DBUS_SSSD_USERS_IF = 'org.freedesktop.sssd.infopipe.Users'
+DBUS_SSSD_USER_IF = 'org.freedesktop.sssd.infopipe.Users.User'
+
+
+class _sssd(object):
+    """
+    Auxiliary class for SSSD infopipe DBus.
+    """
+    def __init__(self, log):
+        """
+        Initialize the Users object and interface.
+
+       :raise RemoteRetrieveError: if DBus error occurs
+        """
+        try:
+            self.log = log
+            self._bus = dbus.SystemBus()
+            self._users_obj = self._bus.get_object(
+                DBUS_SSSD_NAME, DBUS_SSSD_USERS_PATH)
+            self._users_iface = dbus.Interface(
+                self._users_obj, DBUS_SSSD_USERS_IF)
+        except dbus.DBusException as e:
+            self.log.error(
+                'Failed to initialize DBus interface {iface}. DBus '
+                'exception is {exc}.'.format(iface=DBUS_SSSD_USERS_IF, exc=e)
+                )
+            raise errors.RemoteRetrieveError(
+                reason=_('Failed to connect to sssd over SystemBus. '
+                         'See details in the error_log'))
+
+    def list_users_by_cert(self, cert):
+        """
+        Look for users matching the cert.
+
+        Call Users.ListByCertificate interface and return a dict
+        with key = domain, value = list of uids
+        corresponding to the users matching the provided cert
+        :param cert: DER cert
+        :raise RemoteRetrieveError: if DBus error occurs
+        """
+        try:
+            pem = x509.make_pem(base64.b64encode(cert))
+            # bug 3306 in sssd returns 0 entry when max_entries = 0
+            # Temp workaround is to use a non-null value, not too high
+            # to avoid reserving unneeded memory
+            max_entries = dbus.UInt32(100)
+            user_paths = self._users_iface.ListByCertificate(pem, max_entries)
+            users = dict()
+            for user_path in user_paths:
+                user_obj = self._bus.get_object(DBUS_SSSD_NAME, user_path)
+                user_iface = dbus.Interface(user_obj, DBUS_PROPERTY_IF)
+                user_login = user_iface.Get(DBUS_SSSD_USER_IF, 'name')
+
+                # Extract name@domain
+                items = user_login.split('@')
+                domain = api.env.realm if len(items) < 2 else items[1]
+                name = items[0]
+
+                # Retrieve the list of users for the given domain,
+                # or initialize to an empty list
+                # and add the name
+                users_for_dom = users.setdefault(domain, list())
+                users_for_dom.append(name)
+            return users
+        except dbus.DBusException as e:
+            err_name = e.get_dbus_name()
+            # If there is no matching user, do not consider this as an
+            # exception and return an empty list
+            if err_name == 'org.freedesktop.sssd.Error.NotFound':
+                return dict()
+            self.log.error(
+                'Failed to use interface {iface}. DBus '
+                'exception is {exc}.'.format(iface=DBUS_SSSD_USERS_IF, exc=e))
+            raise errors.RemoteRetrieveError(
+                reason=_('Failed to find users over SystemBus. '
+                         ' See details in the error_log'))
+
+
+@register()
+class certmap(Object):
+    """
+    virtual object for certmatch_map API
+    """
+    takes_params = (
+        DNSNameParam(
+            'domain',
+            label=_('Domain'),
+            flags={'no_search'},
+        ),
+        Str(
+            'uid*',
+            label=_('User logins'),
+            flags={'no_search'},
+        ),
+    )
+
+
+@register()
+class certmap_match(Search):
+    __doc__ = _("""
+    Search for users matching the provided certificate.
+
+    This command relies on SSSD to retrieve the list of matching users and
+    may return cached data. For more information on purging SSSD cache,
+    please refer to sss_cache documentation.
+    """)
+
+    msg_summary = ngettext('%(count)s user matched',
+                           '%(count)s users matched', 0)
+
+    def get_summary_default(self, output):
+        """
+        Need to sum the numbre of matching users for each domain.
+        """
+        count = sum(len(entry['uid']) for entry in output['result'])
+        return self.msg_summary % dict(count=count)
+
+    def get_args(self):
+        for arg in super(certmap_match, self).get_args():
+            if arg.name == 'criteria':
+                continue
+            yield arg
+        yield Bytes(
+            'certificate', validate_certificate,
+            cli_name='certificate',
+            label=_('Certificate'),
+            doc=_('Base-64 encoded user certificate'),
+            flags=['virtual_attribute']
+        )
+
+    def execute(self, *args, **options):
+        """
+        Search for users matching the provided certificate.
+
+        The search is performed using SSSD's DBus interface
+        Users.ListByCertificate.
+        SSSD does the lookup based on certificate mapping rules, using
+        FreeIPA domain and trusted domains.
+        :raise RemoteRetrieveError: if DBus returns an exception
+        """
+        sssd = _sssd(self.log)
+
+        cert = args[0]
+        users = sssd.list_users_by_cert(cert)
+        result = [{'domain': domain, 'uid': userlist}
+                  for (domain, userlist) in users.items()]
+        count = len(result)
+
+        return dict(
+            result=result,
+            count=count,
+            truncated=False,
+        )