From 3cbf2b25422100cc4105dfb09ee8c7bf87232198 Mon Sep 17 00:00:00 2001

From: Rob Crittenden <rcritten@redhat.com>

Date: Mon, 22 Aug 2022 10:57:14 -0400

Subject: [PATCH] Defer creating the final krb5.conf on clients

A temporary krb5.conf is created early during client enrollment

and was previously used only during the initial ipa-join call.

The final krb5.conf was written soon afterward.

If there are multiple servers it is possible that the client

may then choose a different KDC to connect. If the client

is faster than replication then the client may not exist

on all servers and therefore enrollment will fail.

This was seen in performance testing of how many simultaneous

client enrollments are possible.

Use a decorator to wrap the _install() method to ensure the

temporary files created during installation are cleaned up.

https://pagure.io/freeipa/issue/9228

Signed-off-by: Rob Crittenden <rcritten@redhat.com>

Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>

---

 ipaclient/install/client.py | 377 +++++++++++++++++++-----------------

 1 file changed, 196 insertions(+), 181 deletions(-)

diff --git a/ipaclient/install/client.py b/ipaclient/install/client.py

index 920c517d4f2b5414d8d2af63d029949cb4f02dc6..93bc7400805dafffcb3909771f0458e5b7e4a764 100644

--- a/ipaclient/install/client.py

+++ b/ipaclient/install/client.py

@@ -101,6 +101,37 @@ cli_basedn = None

 # end of global variables

+def cleanup(func):

+    def inner(options, tdict):

+        # Add some additional options which contain the temporary files

+        # needed during installation.

+        fd, krb_name = tempfile.mkstemp()

+        os.close(fd)

+        ccache_dir = tempfile.mkdtemp(prefix='krbcc')

+

+        tdict['krb_name'] = krb_name

+        tdict['ccache_dir'] = ccache_dir

+

+        func(options, tdict)

+

+        os.environ.pop('KRB5_CONFIG', None)

+

+        try:

+            os.remove(krb_name)

+        except OSError:

+            logger.error("Could not remove %s", krb_name)

+        try:

+            os.rmdir(ccache_dir)

+        except OSError:

+            pass

+        try:

+            os.remove(krb_name + ".ipabkp")

+        except OSError:

+            logger.error("Could not remove %s.ipabkp", krb_name)

+

+    return inner

+

+

 def remove_file(filename):

     """

     Deletes a file. If the file does not exist (OSError 2) does nothing.

@@ -2652,7 +2683,7 @@ def restore_time_sync(statestore, fstore):

 def install(options):

     try:

-        _install(options)

+        _install(options, dict())

     except ScriptError as e:

         if e.rval == CLIENT_INSTALL_ERROR:

             if options.force:

@@ -2679,7 +2710,8 @@ def install(options):

             pass

-def _install(options):

+@cleanup

+def _install(options, tdict):

     env = {'PATH': SECURE_PATH}

     fstore = sysrestore.FileStore(paths.IPA_CLIENT_SYSRESTORE)

@@ -2687,6 +2719,9 @@ def _install(options):

     statestore.backup_state('installation', 'complete', False)

+    krb_name = tdict['krb_name']

+    ccache_dir = tdict['ccache_dir']

+

     if not options.on_master:

         # Try removing old principals from the keytab

         purge_host_keytab(cli_realm)

@@ -2719,182 +2754,162 @@ def _install(options):

     host_principal = 'host/%s@%s' % (hostname, cli_realm)

     if not options.on_master:

         nolog = tuple()

-        # First test out the kerberos configuration

-        fd, krb_name = tempfile.mkstemp()

-        os.close(fd)

-        ccache_dir = tempfile.mkdtemp(prefix='krbcc')

-        try:

-            configure_krb5_conf(

-                cli_realm=cli_realm,

-                cli_domain=cli_domain,

-                cli_server=cli_server,

-                cli_kdc=cli_kdc,

-                dnsok=False,

-                filename=krb_name,

-                client_domain=client_domain,

-                client_hostname=hostname,

-                configure_sssd=options.sssd,

-                force=options.force)

-            env['KRB5_CONFIG'] = krb_name

-            ccache_name = os.path.join(ccache_dir, 'ccache')

-            join_args = [

-                paths.SBIN_IPA_JOIN,

-                "-s", cli_server[0],

-                "-b", str(realm_to_suffix(cli_realm)),

-                "-h", hostname,

-                "-k", paths.KRB5_KEYTAB

-            ]

-            if options.debug:

-                join_args.append("-d")

-                env['XMLRPC_TRACE_CURL'] = 'yes'

-            if options.force_join:

-                join_args.append("-f")

-            if options.principal is not None:

-                stdin = None

-                principal = options.principal

-                if principal.find('@') == -1:

-                    principal = '%s@%s' % (principal, cli_realm)

-                if options.password is not None:

-                    stdin = options.password

+        configure_krb5_conf(

+            cli_realm=cli_realm,

+            cli_domain=cli_domain,

+            cli_server=cli_server,

+            cli_kdc=cli_kdc,

+            dnsok=False,

+            filename=krb_name,

+            client_domain=client_domain,

+            client_hostname=hostname,

+            configure_sssd=options.sssd,

+            force=options.force)

+        env['KRB5_CONFIG'] = krb_name

+        ccache_name = os.path.join(ccache_dir, 'ccache')

+        join_args = [

+            paths.SBIN_IPA_JOIN,

+            "-s", cli_server[0],

+            "-b", str(realm_to_suffix(cli_realm)),

+            "-h", hostname,

+            "-k", paths.KRB5_KEYTAB

+        ]

+        if options.debug:

+            join_args.append("-d")

+            env['XMLRPC_TRACE_CURL'] = 'yes'

+        if options.force_join:

+            join_args.append("-f")

+        if options.principal is not None:

+            stdin = None

+            principal = options.principal

+            if principal.find('@') == -1:

+                principal = '%s@%s' % (principal, cli_realm)

+            if options.password is not None:

+                stdin = options.password

+            else:

+                if not options.unattended:

+                    try:

+                        stdin = getpass.getpass(

+                            "Password for %s: " % principal)

+                    except EOFError:

+                        stdin = None

+                    if not stdin:

+                        raise ScriptError(

+                            "Password must be provided for {}.".format(

+                                principal),

+                            rval=CLIENT_INSTALL_ERROR)

                 else:

-                    if not options.unattended:

-                        try:

-                            stdin = getpass.getpass(

-                                "Password for %s: " % principal)

-                        except EOFError:

-                            stdin = None

-                        if not stdin:

-                            raise ScriptError(

-                                "Password must be provided for {}.".format(

-                                    principal),

-                                rval=CLIENT_INSTALL_ERROR)

+                    if sys.stdin.isatty():

+                        logger.error(

+                            "Password must be provided in "

+                            "non-interactive mode.")

+                        logger.info(

+                            "This can be done via "

+                            "echo password | ipa-client-install ... "

+                            "or with the -w option.")

+                        raise ScriptError(rval=CLIENT_INSTALL_ERROR)

                     else:

-                        if sys.stdin.isatty():

-                            logger.error(

-                                "Password must be provided in "

-                                "non-interactive mode.")

-                            logger.info(

-                                "This can be done via "

-                                "echo password | ipa-client-install ... "

-                                "or with the -w option.")

-                            raise ScriptError(rval=CLIENT_INSTALL_ERROR)

-                        else:

-                            stdin = sys.stdin.readline()

+                        stdin = sys.stdin.readline()

+            try:

+                kinit_password(principal, stdin, ccache_name,

+                               config=krb_name)

+            except RuntimeError as e:

+                print_port_conf_info()

+                raise ScriptError(

+                    "Kerberos authentication failed: {}".format(e),

+                    rval=CLIENT_INSTALL_ERROR)

+        elif options.keytab:

+            join_args.append("-f")

+            if os.path.exists(options.keytab):

                 try:

-                    kinit_password(principal, stdin, ccache_name,

-                                   config=krb_name)

-                except RuntimeError as e:

+                    kinit_keytab(host_principal,

+                                 options.keytab,

+                                 ccache_name,

+                                 config=krb_name,

+                                 attempts=options.kinit_attempts)

+                except gssapi.exceptions.GSSError as e:

                     print_port_conf_info()

                     raise ScriptError(

                         "Kerberos authentication failed: {}".format(e),

                         rval=CLIENT_INSTALL_ERROR)

-            elif options.keytab:

-                join_args.append("-f")

-                if os.path.exists(options.keytab):

-                    try:

-                        kinit_keytab(host_principal,

-                                     options.keytab,

-                                     ccache_name,

-                                     config=krb_name,

-                                     attempts=options.kinit_attempts)

-                    except gssapi.exceptions.GSSError as e:

-                        print_port_conf_info()

-                        raise ScriptError(

-                            "Kerberos authentication failed: {}".format(e),

-                            rval=CLIENT_INSTALL_ERROR)

-                else:

-                    raise ScriptError(

-                        "Keytab file could not be found: {}".format(

-                            options.keytab),

-                        rval=CLIENT_INSTALL_ERROR)

-            elif options.password:

-                nolog = (options.password,)

-                join_args.append("-w")

-                join_args.append(options.password)

-            elif options.prompt_password:

-                if options.unattended:

-                    raise ScriptError(

-                        "Password must be provided in non-interactive mode",

-                        rval=CLIENT_INSTALL_ERROR)

-                try:

-                    password = getpass.getpass("Password: ")

-                except EOFError:

-                    password = None

-                if not password:

-                    raise ScriptError(

-                        "Password must be provided.",

-                        rval=CLIENT_INSTALL_ERROR)

-                join_args.append("-w")

-                join_args.append(password)

-                nolog = (password,)

-

-            env['KRB5CCNAME'] = os.environ['KRB5CCNAME'] = ccache_name

-            # Get the CA certificate

+            else:

+                raise ScriptError(

+                    "Keytab file could not be found: {}".format(

+                        options.keytab),

+                    rval=CLIENT_INSTALL_ERROR)

+        elif options.password:

+            nolog = (options.password,)

+            join_args.append("-w")

+            join_args.append(options.password)

+        elif options.prompt_password:

+            if options.unattended:

+                raise ScriptError(

+                    "Password must be provided in non-interactive mode",

+                    rval=CLIENT_INSTALL_ERROR)

             try:

-                os.environ['KRB5_CONFIG'] = env['KRB5_CONFIG']

-                get_ca_certs(fstore, options, cli_server[0], cli_basedn,

-                             cli_realm)

-                del os.environ['KRB5_CONFIG']

-            except errors.FileError as e:

-                logger.error('%s', e)

-                raise ScriptError(rval=CLIENT_INSTALL_ERROR)

-            except Exception as e:

-                logger.error("Cannot obtain CA certificate\n%s", e)

-                raise ScriptError(rval=CLIENT_INSTALL_ERROR)

-

-            # Now join the domain

-            result = run(

-                join_args, raiseonerr=False, env=env, nolog=nolog,

-                capture_error=True)

-            stderr = result.error_output

+                password = getpass.getpass("Password: ")

+            except EOFError:

+                password = None

+            if not password:

+                raise ScriptError(

+                    "Password must be provided.",

+                    rval=CLIENT_INSTALL_ERROR)

+            join_args.append("-w")

+            join_args.append(password)

+            nolog = (password,)

-            if result.returncode != 0:

-                logger.error("Joining realm failed: %s", stderr)

-                if not options.force:

-                    if result.returncode == 13:

-                        logger.info(

-                            "Use --force-join option to override the host "

-                            "entry on the server and force client enrollment.")

-                    raise ScriptError(rval=CLIENT_INSTALL_ERROR)

-                logger.info(

-                    "Use ipa-getkeytab to obtain a host "

-                    "principal for this server.")

-            else:

-                logger.info("Enrolled in IPA realm %s", cli_realm)

+        env['KRB5CCNAME'] = os.environ['KRB5CCNAME'] = ccache_name

+        # Get the CA certificate

+        try:

+            os.environ['KRB5_CONFIG'] = env['KRB5_CONFIG']

+            get_ca_certs(fstore, options, cli_server[0], cli_basedn,

+                         cli_realm)

+        except errors.FileError as e:

+            logger.error('%s', e)

+            raise ScriptError(rval=CLIENT_INSTALL_ERROR)

+        except Exception as e:

+            logger.error("Cannot obtain CA certificate\n%s", e)

+            raise ScriptError(rval=CLIENT_INSTALL_ERROR)

-            if options.principal is not None:

-                run([paths.KDESTROY], raiseonerr=False, env=env)

+        # Now join the domain

+        result = run(

+            join_args, raiseonerr=False, env=env, nolog=nolog,

+            capture_error=True)

+        stderr = result.error_output

-            # Obtain the TGT. We do it with the temporary krb5.conf, so that

-            # only the KDC we're installing under is contacted.

-            # Other KDCs might not have replicated the principal yet.

-            # Once we have the TGT, it's usable on any server.

-            try:

-                kinit_keytab(host_principal, paths.KRB5_KEYTAB, CCACHE_FILE,

-                             config=krb_name,

-                             attempts=options.kinit_attempts)

-                env['KRB5CCNAME'] = os.environ['KRB5CCNAME'] = CCACHE_FILE

-            except gssapi.exceptions.GSSError as e:

-                print_port_conf_info()

-                logger.error("Failed to obtain host TGT: %s", e)

-                # failure to get ticket makes it impossible to login and bind

-                # from sssd to LDAP, abort installation and rollback changes

+        if result.returncode != 0:

+            logger.error("Joining realm failed: %s", stderr)

+            if not options.force:

+                if result.returncode == 13:

+                    logger.info(

+                        "Use --force-join option to override the host "

+                        "entry on the server and force client enrollment.")

                 raise ScriptError(rval=CLIENT_INSTALL_ERROR)

+            logger.info(

+                "Use ipa-getkeytab to obtain a host "

+                "principal for this server.")

+        else:

+            logger.info("Enrolled in IPA realm %s", cli_realm)

-        finally:

-            try:

-                os.remove(krb_name)

-            except OSError:

-                logger.error("Could not remove %s", krb_name)

-            try:

-                os.rmdir(ccache_dir)

-            except OSError:

-                pass

-            try:

-                os.remove(krb_name + ".ipabkp")

-            except OSError:

-                logger.error("Could not remove %s.ipabkp", krb_name)

+        if options.principal is not None:

+            run([paths.KDESTROY], raiseonerr=False, env=env)

+

+        # Obtain the TGT. We do it with the temporary krb5.conf, so that

+        # only the KDC we're installing under is contacted.

+        # Other KDCs might not have replicated the principal yet.

+        # Once we have the TGT, it's usable on any server.

+        try:

+            kinit_keytab(host_principal, paths.KRB5_KEYTAB, CCACHE_FILE,

+                         config=krb_name,

+                         attempts=options.kinit_attempts)

+            env['KRB5CCNAME'] = os.environ['KRB5CCNAME'] = CCACHE_FILE

+        except gssapi.exceptions.GSSError as e:

+            print_port_conf_info()

+            logger.error("Failed to obtain host TGT: %s", e)

+            # failure to get ticket makes it impossible to login and bind

+            # from sssd to LDAP, abort installation and rollback changes

+            raise ScriptError(rval=CLIENT_INSTALL_ERROR)

     # Configure ipa.conf

     if not options.on_master:

@@ -2931,23 +2946,6 @@ def _install(options):

             except gssapi.exceptions.GSSError as e:

                 logger.error("Failed to obtain host TGT: %s", e)

                 raise ScriptError(rval=CLIENT_INSTALL_ERROR)

-        else:

-            # Configure krb5.conf

-            fstore.backup_file(paths.KRB5_CONF)

-            configure_krb5_conf(

-                cli_realm=cli_realm,

-                cli_domain=cli_domain,

-                cli_server=cli_server,

-                cli_kdc=cli_kdc,

-                dnsok=dnsok,

-                filename=paths.KRB5_CONF,

-                client_domain=client_domain,

-                client_hostname=hostname,

-                configure_sssd=options.sssd,

-                force=options.force)

-

-            logger.info(

-                "Configured /etc/krb5.conf for IPA realm %s", cli_realm)

         # Clear out any current session keyring information

         try:

@@ -3274,6 +3272,23 @@ def _install(options):

         configure_nisdomain(

             options=options, domain=cli_domain, statestore=statestore)

+    # Configure the final krb5.conf

+    if not options.on_master:

+        fstore.backup_file(paths.KRB5_CONF)

+        configure_krb5_conf(

+            cli_realm=cli_realm,

+            cli_domain=cli_domain,

+            cli_server=cli_server,

+            cli_kdc=cli_kdc,

+            dnsok=dnsok,

+            filename=paths.KRB5_CONF,

+            client_domain=client_domain,

+            client_hostname=hostname,

+            configure_sssd=options.sssd,

+            force=options.force)

+

+        logger.info("Configured /etc/krb5.conf for IPA realm %s", cli_realm)

+

     statestore.delete_state('installation', 'complete')

     statestore.backup_state('installation', 'complete', True)

     logger.info('Client configuration complete.')

-- 

2.38.1