Add support for re-enrolling hosts using keytab

A host that has been recreated  and does not have its
host entry disabled or removed, can be re-enrolled using
a previously backed up keytab file.

A new option --keytab has been added to ipa-client-install. This
can be used to specify path to the keytab and can be used instead
of -p or -w options.

A new option -f has been added to ipa-join. It forces client to
join even if the host entry already exits. A new certificate,
ssh keys are generated, ipaUniqueID stays the same.

Design page: http://freeipa.org/page/V3/Client_install_using_keytab

https://fedorahosted.org/freeipa/ticket/3374

1 files changed, 35 insertions, 5 deletions

diff --git a/ipa-client/ipa-install/ipa-client-install b/ipa-client/ipa-install/ipa-client-install
index 308c3f8d0..bd458ed09 100755
--- a/ipa-client/ipa-install/ipa-client-install
+++ b/ipa-client/ipa-install/ipa-client-install
@@ -104,6 +104,8 @@ def parse_options():
                       help="principal to use to join the IPA realm"),
     basic_group.add_option("-w", "--password", dest="password", sensitive=True,
                       help="password to join the IPA realm (assumes bulk password unless principal is also set)"),
+    basic_group.add_option("-k", "--keytab", dest="keytab",
+                      help="path to backed up keytab from previous enrollment"),
     basic_group.add_option("-W", dest="prompt_password", action="store_true",
                       default=False,
                       help="Prompt for a password to join the IPA realm"),
@@ -1691,8 +1693,12 @@ def install(options, env, fstore, statestore):
         except ipaclient.ntpconf.NTPConfigurationError:
             pass
 
-    if options.unattended and (options.password is None and options.principal is None and options.prompt_password is False) and not options.on_master:
-        root_logger.error("One of password and principal are required.")
+    if options.unattended and (options.password is None and
+                               options.principal is None and
+                               options.keytab is None and
+                               options.prompt_password is False and
+                               not options.on_master):
+        root_logger.error("One of password / principal / keytab is required.")
         return CLIENT_INSTALL_ERROR
 
     if options.hostname:
@@ -1910,8 +1916,10 @@ def install(options, env, fstore, statestore):
         ipaservices.backup_and_replace_hostname(fstore, statestore, options.hostname)
 
     if not options.unattended:
-        if options.principal is None and options.password is None and options.prompt_password is False:
-            options.principal = user_input("User authorized to enroll computers", allow_empty=False)
+        if (options.principal is None and options.password is None and
+                options.prompt_password is False and options.keytab is None):
+            options.principal = user_input("User authorized to enroll "
+                                           "computers", allow_empty=False)
             root_logger.debug(
                 "will use principal provided as option: %s", options.principal)
 
@@ -1985,12 +1993,34 @@ def install(options, env, fstore, statestore):
                         else:
                             stdin = sys.stdin.readline()
 
-                (stderr, stdout, returncode) = run(["kinit", principal], raiseonerr=False, stdin=stdin, env=env)
+                (stderr, stdout, returncode) = run(["kinit", principal],
+                                                    raiseonerr=False,
+                                                    stdin=stdin,
+                                                    env=env)
                 if returncode != 0:
                     root_logger.error("Kerberos authentication failed")
                     root_logger.info("%s", stdout)
                     print_port_conf_info()
                     return CLIENT_INSTALL_ERROR
+            elif options.keytab:
+                join_args.append("-f")
+                if os.path.exists(options.keytab):
+                    (stderr, stdout, returncode) = run(
+                        ['/usr/bin/kinit','-k', '-t', options.keytab,
+                            'host/%s@%s' % (hostname, cli_realm)],
+                        env=env,
+                        raiseonerr=False)
+
+                    if returncode != 0:
+                        root_logger.error("Kerberos authentication failed "
+                                          "using keytab: %s", options.keytab)
+                        root_logger.info("%s", stdout)
+                        print_port_conf_info()
+                        return CLIENT_INSTALL_ERROR
+                else:
+                    root_logger.error("Keytab file could not be found: %s"
+                                      % options.keytab)
+                    return CLIENT_INSTALL_ERROR
             elif options.password:
                 nolog = (options.password,)
                 join_args.append("-w")