ipautil: move kinit functions to ipalib.install

kinit_password() depends on ipaplatform.

Move kinit_password() as well as kinit_keytab() to a new
ipalib.install.kinit module, as they are used only from installers.

https://fedorahosted.org/freeipa/ticket/6474

Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/ipalib/install/kinit.py b/ipalib/install/kinit.py
new file mode 100644
index 000000000..2c59b5e13
--- /dev/null
+++ b/ipalib/install/kinit.py
@@ -0,0 +1,97 @@
+#
+# Copyright (C) 2016  FreeIPA Contributors see COPYING for license
+#
+
+import os
+import time
+
+import gssapi
+
+from ipaplatform.paths import paths
+from ipapython.ipa_log_manager import root_logger
+from ipapython.ipautil import run
+
+# Cannot contact any KDC for requested realm
+KRB5_KDC_UNREACH = 2529639068
+
+# A service is not available that s required to process the request
+KRB5KDC_ERR_SVC_UNAVAILABLE = 2529638941
+
+
+def kinit_keytab(principal, keytab, ccache_name, config=None, attempts=1):
+    """
+    Given a ccache_path, keytab file and a principal kinit as that user.
+
+    The optional parameter 'attempts' specifies how many times the credential
+    initialization should be attempted in case of non-responsive KDC.
+    """
+    errors_to_retry = {KRB5KDC_ERR_SVC_UNAVAILABLE,
+                       KRB5_KDC_UNREACH}
+    root_logger.debug("Initializing principal %s using keytab %s"
+                      % (principal, keytab))
+    root_logger.debug("using ccache %s" % ccache_name)
+    for attempt in range(1, attempts + 1):
+        old_config = os.environ.get('KRB5_CONFIG')
+        if config is not None:
+            os.environ['KRB5_CONFIG'] = config
+        else:
+            os.environ.pop('KRB5_CONFIG', None)
+        try:
+            name = gssapi.Name(principal, gssapi.NameType.kerberos_principal)
+            store = {'ccache': ccache_name,
+                     'client_keytab': keytab}
+            cred = gssapi.Credentials(name=name, store=store, usage='initiate')
+            root_logger.debug("Attempt %d/%d: success"
+                              % (attempt, attempts))
+            return cred
+        except gssapi.exceptions.GSSError as e:
+            if e.min_code not in errors_to_retry:  # pylint: disable=no-member
+                raise
+            root_logger.debug("Attempt %d/%d: failed: %s"
+                              % (attempt, attempts, e))
+            if attempt == attempts:
+                root_logger.debug("Maximum number of attempts (%d) reached"
+                                  % attempts)
+                raise
+            root_logger.debug("Waiting 5 seconds before next retry")
+            time.sleep(5)
+        finally:
+            if old_config is not None:
+                os.environ['KRB5_CONFIG'] = old_config
+            else:
+                os.environ.pop('KRB5_CONFIG', None)
+
+
+def kinit_password(principal, password, ccache_name, config=None,
+                   armor_ccache_name=None, canonicalize=False,
+                   enterprise=False):
+    """
+    perform interactive kinit as principal using password. If using FAST for
+    web-based authentication, use armor_ccache_path to specify http service
+    ccache.
+    """
+    root_logger.debug("Initializing principal %s using password" % principal)
+    args = [paths.KINIT, principal, '-c', ccache_name]
+    if armor_ccache_name is not None:
+        root_logger.debug("Using armor ccache %s for FAST webauth"
+                          % armor_ccache_name)
+        args.extend(['-T', armor_ccache_name])
+
+    if canonicalize:
+        root_logger.debug("Requesting principal canonicalization")
+        args.append('-C')
+
+    if enterprise:
+        root_logger.debug("Using enterprise principal")
+        args.append('-E')
+
+    env = {'LC_ALL': 'C'}
+    if config is not None:
+        env['KRB5_CONFIG'] = config
+
+    # this workaround enables us to capture stderr and put it
+    # into the raised exception in case of unsuccessful authentication
+    result = run(args, stdin=password, env=env, raiseonerr=False,
+                 capture_error=True)
+    if result.returncode:
+        raise RuntimeError(result.error_output)