Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

13 files changed, 4774 insertions, 0 deletions

diff --git a/source4/auth/gensec/gensec_gssapi.c b/source4/auth/gensec/gensec_gssapi.c
new file mode 100644
index 0000000..cc0491f
--- /dev/null
+++ b/source4/auth/gensec/gensec_gssapi.c
@@ -0,0 +1,1731 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Kerberos backend for GENSEC
+   
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
+   Copyright (C) Stefan Metzmacher <metze@samba.org> 2004-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include <tevent.h>
+#include "lib/util/tevent_ntstatus.h"
+#include "lib/events/events.h"
+#include "system/kerberos.h"
+#include "system/gssapi.h"
+#include "auth/kerberos/kerberos.h"
+#include "librpc/gen_ndr/krb5pac.h"
+#include "auth/auth.h"
+#include <ldb.h>
+#include "auth/auth_sam.h"
+#include "librpc/gen_ndr/dcerpc.h"
+#include "auth/credentials/credentials.h"
+#include "auth/credentials/credentials_krb5.h"
+#include "auth/gensec/gensec.h"
+#include "auth/gensec/gensec_internal.h"
+#include "auth/gensec/gensec_proto.h"
+#include "auth/gensec/gensec_toplevel_proto.h"
+#include "param/param.h"
+#include "auth/session_proto.h"
+#include "gensec_gssapi.h"
+#include "lib/util/util_net.h"
+#include "auth/kerberos/pac_utils.h"
+#include "auth/kerberos/gssapi_helper.h"
+#include "lib/util/smb_strtox.h"
+
+#ifndef gss_mech_spnego
+gss_OID_desc spnego_mech_oid_desc =
+		{ 6, discard_const_p(void, "\x2b\x06\x01\x05\x05\x02") };
+#define gss_mech_spnego (&spnego_mech_oid_desc)
+#endif
+
+_PUBLIC_ NTSTATUS gensec_gssapi_init(TALLOC_CTX *);
+
+static size_t gensec_gssapi_max_input_size(struct gensec_security *gensec_security);
+static size_t gensec_gssapi_max_wrapped_size(struct gensec_security *gensec_security);
+static size_t gensec_gssapi_sig_size(struct gensec_security *gensec_security, size_t data_size);
+
+static int gensec_gssapi_destructor(struct gensec_gssapi_state *gensec_gssapi_state)
+{
+	OM_uint32 min_stat;
+
+	if (gensec_gssapi_state->delegated_cred_handle != GSS_C_NO_CREDENTIAL) {
+		gss_release_cred(&min_stat,
+				 &gensec_gssapi_state->delegated_cred_handle);
+	}
+
+	if (gensec_gssapi_state->gssapi_context != GSS_C_NO_CONTEXT) {
+		gss_delete_sec_context(&min_stat,
+				       &gensec_gssapi_state->gssapi_context,
+				       GSS_C_NO_BUFFER);
+	}
+
+	if (gensec_gssapi_state->server_name != GSS_C_NO_NAME) {
+		gss_release_name(&min_stat,
+				 &gensec_gssapi_state->server_name);
+	}
+	if (gensec_gssapi_state->client_name != GSS_C_NO_NAME) {
+		gss_release_name(&min_stat,
+				 &gensec_gssapi_state->client_name);
+	}
+
+	return 0;
+}
+
+static NTSTATUS gensec_gssapi_setup_server_principal(TALLOC_CTX *mem_ctx,
+						     const char *target_principal,
+						     const char *service,
+						     const char *hostname,
+						     const char *realm,
+						     const gss_OID mech,
+						     char **pserver_principal,
+						     gss_name_t *pserver_name)
+{
+	char *server_principal = NULL;
+	gss_buffer_desc name_token;
+	gss_OID name_type;
+	OM_uint32 maj_stat, min_stat = 0;
+
+	if (target_principal != NULL) {
+		server_principal = talloc_strdup(mem_ctx, target_principal);
+		name_type = GSS_C_NULL_OID;
+	} else {
+		server_principal = talloc_asprintf(mem_ctx,
+						   "%s/%s@%s",
+						   service, hostname, realm);
+		name_type = GSS_C_NT_USER_NAME;
+	}
+	if (server_principal == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	name_token.value = (uint8_t *)server_principal;
+	name_token.length = strlen(server_principal);
+
+	maj_stat = gss_import_name(&min_stat,
+				   &name_token,
+				   name_type,
+				   pserver_name);
+	if (maj_stat) {
+		DBG_WARNING("GSS Import name of %s failed: %s\n",
+			    server_principal,
+			    gssapi_error_string(mem_ctx,
+						maj_stat,
+						min_stat,
+						mech));
+		TALLOC_FREE(server_principal);
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	*pserver_principal = server_principal;
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_start(struct gensec_security *gensec_security)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state;
+	krb5_error_code ret;
+#ifdef SAMBA4_USES_HEIMDAL
+	const char *realm;
+#endif
+
+	gensec_gssapi_state = talloc_zero(gensec_security, struct gensec_gssapi_state);
+	if (!gensec_gssapi_state) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	gensec_security->private_data = gensec_gssapi_state;
+
+	gensec_gssapi_state->gssapi_context = GSS_C_NO_CONTEXT;
+
+	/* TODO: Fill in channel bindings */
+	gensec_gssapi_state->input_chan_bindings = GSS_C_NO_CHANNEL_BINDINGS;
+
+	gensec_gssapi_state->server_name = GSS_C_NO_NAME;
+	gensec_gssapi_state->client_name = GSS_C_NO_NAME;
+	
+	gensec_gssapi_state->gss_want_flags = 0;
+	gensec_gssapi_state->expire_time = GENSEC_EXPIRE_TIME_INFINITY;
+
+	if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "delegation_by_kdc_policy", true)) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_DELEG_POLICY_FLAG;
+	}
+	if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "mutual", true)) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_MUTUAL_FLAG;
+	}
+	if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "delegation", false)) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_DELEG_FLAG;
+	}
+	if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "replay", true)) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_REPLAY_FLAG;
+	}
+	if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "sequence", true)) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_SEQUENCE_FLAG;
+	}
+
+	if (gensec_security->want_features & GENSEC_FEATURE_SESSION_KEY) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_INTEG_FLAG;
+	}
+	if (gensec_security->want_features & GENSEC_FEATURE_SIGN) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_INTEG_FLAG;
+	}
+	if (gensec_security->want_features & GENSEC_FEATURE_SEAL) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_INTEG_FLAG;
+		gensec_gssapi_state->gss_want_flags |= GSS_C_CONF_FLAG;
+	}
+	if (gensec_security->want_features & GENSEC_FEATURE_DCE_STYLE) {
+		gensec_gssapi_state->gss_want_flags |= GSS_C_DCE_STYLE;
+	}
+
+	gensec_gssapi_state->gss_got_flags = 0;
+
+	switch (gensec_security->ops->auth_type) {
+	case DCERPC_AUTH_TYPE_SPNEGO:
+		gensec_gssapi_state->gss_oid = gss_mech_spnego;
+		break;
+	case DCERPC_AUTH_TYPE_KRB5:
+	default:
+		gensec_gssapi_state->gss_oid =
+			discard_const_p(void, gss_mech_krb5);
+		break;
+	}
+
+	ret = smb_krb5_init_context(gensec_gssapi_state,
+				    gensec_security->settings->lp_ctx,
+				    &gensec_gssapi_state->smb_krb5_context);
+	if (ret) {
+		DEBUG(1,("gensec_gssapi_start: smb_krb5_init_context failed (%s)\n",
+			 error_message(ret)));
+		talloc_free(gensec_gssapi_state);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	gensec_gssapi_state->client_cred = NULL;
+	gensec_gssapi_state->server_cred = NULL;
+
+	gensec_gssapi_state->delegated_cred_handle = GSS_C_NO_CREDENTIAL;
+
+	gensec_gssapi_state->sasl = false;
+	gensec_gssapi_state->sasl_state = STAGE_GSS_NEG;
+	gensec_gssapi_state->sasl_protection = 0;
+
+	gensec_gssapi_state->max_wrap_buf_size
+		= gensec_setting_int(gensec_security->settings, "gensec_gssapi", "max wrap buf size", 65536);
+	gensec_gssapi_state->gss_exchange_count = 0;
+	gensec_gssapi_state->sig_size = 0;
+
+	talloc_set_destructor(gensec_gssapi_state, gensec_gssapi_destructor);
+
+#ifdef SAMBA4_USES_HEIMDAL
+	realm = lpcfg_realm(gensec_security->settings->lp_ctx);
+	if (realm != NULL) {
+		ret = gsskrb5_set_default_realm(realm);
+		if (ret) {
+			DEBUG(1,("gensec_gssapi_start: gsskrb5_set_default_realm failed\n"));
+			talloc_free(gensec_gssapi_state);
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+	}
+
+	/* don't do DNS lookups of any kind, it might/will fail for a netbios name */
+	ret = gsskrb5_set_dns_canonicalize(false);
+	if (ret) {
+		DEBUG(1,("gensec_gssapi_start: gsskrb5_set_dns_canonicalize failed\n"));
+		talloc_free(gensec_gssapi_state);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+#endif
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_server_start(struct gensec_security *gensec_security)
+{
+	NTSTATUS nt_status;
+	int ret;
+	struct gensec_gssapi_state *gensec_gssapi_state;
+	struct cli_credentials *machine_account;
+	struct gssapi_creds_container *gcc;
+
+	nt_status = gensec_gssapi_start(gensec_security);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		return nt_status;
+	}
+
+	gensec_gssapi_state = talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+
+	machine_account = gensec_get_credentials(gensec_security);
+	
+	if (!machine_account) {
+		DEBUG(3, ("No machine account credentials specified\n"));
+		return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
+	} else {
+		ret = cli_credentials_get_server_gss_creds(machine_account, 
+							   gensec_security->settings->lp_ctx, &gcc);
+		if (ret) {
+			DEBUG(1, ("Acquiring acceptor credentials failed: %s\n",
+				  error_message(ret)));
+			return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
+		}
+	}
+
+	gensec_gssapi_state->server_cred = gcc;
+	return NT_STATUS_OK;
+
+}
+
+static NTSTATUS gensec_gssapi_sasl_server_start(struct gensec_security *gensec_security)
+{
+	NTSTATUS nt_status;
+	struct gensec_gssapi_state *gensec_gssapi_state;
+	nt_status = gensec_gssapi_server_start(gensec_security);
+
+	if (NT_STATUS_IS_OK(nt_status)) {
+		gensec_gssapi_state = talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+		gensec_gssapi_state->sasl = true;
+	}
+	return nt_status;
+}
+
+static NTSTATUS gensec_gssapi_client_creds(struct gensec_security *gensec_security,
+					   struct tevent_context *ev)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state;
+	struct gssapi_creds_container *gcc;
+	struct cli_credentials *creds = gensec_get_credentials(gensec_security);
+	const char *error_string;
+	int ret;
+
+	gensec_gssapi_state = talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+
+	/* Only run this the first time the update() call is made */
+	if (gensec_gssapi_state->client_cred) {
+		return NT_STATUS_OK;
+	}
+
+	ret = cli_credentials_get_client_gss_creds(creds,
+						   ev,
+						   gensec_security->settings->lp_ctx, &gcc, &error_string);
+	switch (ret) {
+	case 0:
+		break;
+	case EINVAL:
+		DEBUG(3, ("Cannot obtain client GSS credentials we need to contact %s : %s\n", gensec_gssapi_state->target_principal, error_string));
+		return NT_STATUS_INVALID_PARAMETER;
+	case KRB5KDC_ERR_PREAUTH_FAILED:
+	case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
+	case KRB5KRB_AP_ERR_BAD_INTEGRITY:
+		DEBUG(1, ("Wrong username or password: %s\n", error_string));
+		return NT_STATUS_LOGON_FAILURE;
+	case KRB5KDC_ERR_CLIENT_REVOKED:
+		DEBUG(1, ("Account locked out: %s\n", error_string));
+		return NT_STATUS_ACCOUNT_LOCKED_OUT;
+	case KRB5_REALM_UNKNOWN:
+	case KRB5_KDC_UNREACH:
+		DEBUG(3, ("Cannot reach a KDC we require to contact %s : %s\n", gensec_gssapi_state->target_principal, error_string));
+		return NT_STATUS_NO_LOGON_SERVERS;
+	case KRB5_CC_NOTFOUND:
+	case KRB5_CC_END:
+		DEBUG(2, ("Error obtaining ticket we require to contact %s: (possibly due to clock skew between us and the KDC) %s\n", gensec_gssapi_state->target_principal, error_string));
+		return NT_STATUS_TIME_DIFFERENCE_AT_DC;
+	default:
+		DEBUG(1, ("Acquiring initiator credentials failed: %s\n", error_string));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	gensec_gssapi_state->client_cred = gcc;
+	if (!talloc_reference(gensec_gssapi_state, gcc)) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_client_start(struct gensec_security *gensec_security)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state;
+	struct cli_credentials *creds = gensec_get_credentials(gensec_security);
+	NTSTATUS nt_status;
+	const char *target_principal = NULL;
+	const char *hostname = gensec_get_target_hostname(gensec_security);
+	const char *service = gensec_get_target_service(gensec_security);
+	const char *realm = cli_credentials_get_realm(creds);
+
+	target_principal = gensec_get_target_principal(gensec_security);
+	if (target_principal != NULL) {
+		goto do_start;
+	}
+
+	if (!hostname) {
+		DEBUG(3, ("No hostname for target computer passed in, cannot use kerberos for this connection\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	if (is_ipaddress(hostname)) {
+		DEBUG(2, ("Cannot do GSSAPI to an IP address\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	if (strcmp(hostname, "localhost") == 0) {
+		DEBUG(2, ("GSSAPI to 'localhost' does not make sense\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (realm == NULL) {
+		char *cred_name = cli_credentials_get_unparsed_name(creds,
+								gensec_security);
+		DEBUG(3, ("cli_credentials(%s) without realm, "
+			  "cannot use kerberos for this connection %s/%s\n",
+			  cred_name, service, hostname));
+		TALLOC_FREE(cred_name);
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+do_start:
+
+	nt_status = gensec_gssapi_start(gensec_security);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		return nt_status;
+	}
+
+	gensec_gssapi_state = talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+
+	if (cli_credentials_get_impersonate_principal(creds)) {
+		gensec_gssapi_state->gss_want_flags &= ~(GSS_C_DELEG_FLAG|GSS_C_DELEG_POLICY_FLAG);
+	}
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_sasl_client_start(struct gensec_security *gensec_security)
+{
+	NTSTATUS nt_status;
+	struct gensec_gssapi_state *gensec_gssapi_state;
+	nt_status = gensec_gssapi_client_start(gensec_security);
+
+	if (NT_STATUS_IS_OK(nt_status)) {
+		gensec_gssapi_state = talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+		gensec_gssapi_state->sasl = true;
+	}
+	return nt_status;
+}
+
+static NTSTATUS gensec_gssapi_update_internal(struct gensec_security *gensec_security,
+					      TALLOC_CTX *out_mem_ctx,
+					      struct tevent_context *ev,
+					      const DATA_BLOB in, DATA_BLOB *out)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	NTSTATUS nt_status;
+	OM_uint32 maj_stat, min_stat;
+	OM_uint32 min_stat2;
+	gss_buffer_desc input_token = { 0, NULL };
+	gss_buffer_desc output_token = { 0, NULL };
+	struct cli_credentials *cli_creds = gensec_get_credentials(gensec_security);
+	const char *target_principal = gensec_get_target_principal(gensec_security);
+	const char *hostname = gensec_get_target_hostname(gensec_security);
+	const char *service = gensec_get_target_service(gensec_security);
+	gss_OID gss_oid_p = NULL;
+	OM_uint32 time_req = 0;
+	OM_uint32 time_rec = 0;
+	struct timeval tv;
+
+	time_req = gensec_setting_int(gensec_security->settings,
+				      "gensec_gssapi", "requested_life_time",
+				      time_req);
+
+	input_token.length = in.length;
+	input_token.value = in.data;
+
+	switch (gensec_gssapi_state->sasl_state) {
+	case STAGE_GSS_NEG:
+	{
+		switch (gensec_security->gensec_role) {
+		case GENSEC_CLIENT:
+		{
+			const char *client_realm = NULL;
+#ifdef SAMBA4_USES_HEIMDAL
+			struct gsskrb5_send_to_kdc send_to_kdc;
+			krb5_error_code ret;
+#else
+			bool fallback = false;
+#endif
+
+			nt_status = gensec_gssapi_client_creds(gensec_security, ev);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				return nt_status;
+			}
+
+#ifdef SAMBA4_USES_HEIMDAL
+			send_to_kdc.func = smb_krb5_send_and_recv_func;
+			send_to_kdc.ptr = ev;
+
+			min_stat = gsskrb5_set_send_to_kdc(&send_to_kdc);
+			if (min_stat) {
+				DEBUG(1,("gensec_gssapi_update: gsskrb5_set_send_to_kdc failed\n"));
+				return NT_STATUS_INTERNAL_ERROR;
+			}
+#endif
+
+			/*
+			 * With credentials for
+			 * administrator@FOREST1.EXAMPLE.COM this patch changes
+			 * the target_principal for the ldap service of host
+			 * dc2.forest2.example.com from
+			 *
+			 *   ldap/dc2.forest2.example.com@FOREST1.EXAMPLE.COM
+			 *
+			 * to
+			 *
+			 *   ldap/dc2.forest2.example.com@FOREST2.EXAMPLE.COM
+			 *
+			 * Typically
+			 * ldap/dc2.forest2.example.com@FOREST1.EXAMPLE.COM
+			 * should be used in order to allow the KDC of
+			 * FOREST1.EXAMPLE.COM to generate a referral ticket
+			 * for krbtgt/FOREST2.EXAMPLE.COM@FOREST1.EXAMPLE.COM.
+			 *
+			 * The problem is that KDCs only return such referral
+			 * tickets if there's a forest trust between
+			 * FOREST1.EXAMPLE.COM and FOREST2.EXAMPLE.COM. If
+			 * there's only an external domain trust between
+			 * FOREST1.EXAMPLE.COM and FOREST2.EXAMPLE.COM the KDC
+			 * of FOREST1.EXAMPLE.COM will respond with
+			 * S_PRINCIPAL_UNKNOWN when being asked for
+			 * ldap/dc2.forest2.example.com@FOREST1.EXAMPLE.COM.
+			 *
+			 * In the case of an external trust the client can
+			 * still ask explicitly for
+			 * krbtgt/FOREST2.EXAMPLE.COM@FOREST1.EXAMPLE.COM and
+			 * the KDC of FOREST1.EXAMPLE.COM will generate it.
+			 *
+			 * From there the client can use the
+			 * krbtgt/FOREST2.EXAMPLE.COM@FOREST1.EXAMPLE.COM
+			 * ticket and ask a KDC of FOREST2.EXAMPLE.COM for a
+			 * service ticket for
+			 * ldap/dc2.forest2.example.com@FOREST2.EXAMPLE.COM.
+			 *
+			 * With Heimdal we'll get the fallback on
+			 * S_PRINCIPAL_UNKNOWN behavior when we pass
+			 * ldap/dc2.forest2.example.com@FOREST2.EXAMPLE.COM as
+			 * target principal. As _krb5_get_cred_kdc_any() first
+			 * calls get_cred_kdc_referral() (which always starts
+			 * with the client realm) and falls back to
+			 * get_cred_kdc_capath() (which starts with the given
+			 * realm).
+			 *
+			 * MIT krb5 only tries the given realm of the target
+			 * principal, if we want to autodetect support for
+			 * transitive forest trusts, would have to do the
+			 * fallback ourself.
+			 */
+			client_realm = cli_credentials_get_realm(cli_creds);
+#ifndef SAMBA4_USES_HEIMDAL
+			if (gensec_gssapi_state->server_name == NULL) {
+				nt_status = gensec_gssapi_setup_server_principal(gensec_gssapi_state,
+										 target_principal,
+										 service,
+										 hostname,
+										 client_realm,
+										 gensec_gssapi_state->gss_oid,
+										 &gensec_gssapi_state->target_principal,
+										 &gensec_gssapi_state->server_name);
+				if (!NT_STATUS_IS_OK(nt_status)) {
+					return nt_status;
+				}
+
+				maj_stat = gss_init_sec_context(&min_stat,
+								gensec_gssapi_state->client_cred->creds,
+								&gensec_gssapi_state->gssapi_context,
+								gensec_gssapi_state->server_name,
+								gensec_gssapi_state->gss_oid,
+								gensec_gssapi_state->gss_want_flags,
+								time_req,
+								gensec_gssapi_state->input_chan_bindings,
+								&input_token,
+								&gss_oid_p,
+								&output_token,
+								&gensec_gssapi_state->gss_got_flags, /* ret flags */
+								&time_rec);
+				if (maj_stat != GSS_S_FAILURE) {
+					goto init_sec_context_done;
+				}
+				if (min_stat != (OM_uint32)KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN) {
+					goto init_sec_context_done;
+				}
+				if (target_principal != NULL) {
+					goto init_sec_context_done;
+				}
+
+				fallback = true;
+				TALLOC_FREE(gensec_gssapi_state->target_principal);
+				gss_release_name(&min_stat2, &gensec_gssapi_state->server_name);
+			}
+#endif /* !SAMBA4_USES_HEIMDAL */
+			if (gensec_gssapi_state->server_name == NULL) {
+				const char *server_realm = NULL;
+
+				server_realm = smb_krb5_get_realm_from_hostname(gensec_gssapi_state,
+										hostname,
+										client_realm);
+				if (server_realm == NULL) {
+					return NT_STATUS_NO_MEMORY;
+				}
+
+#ifndef SAMBA4_USES_HEIMDAL
+				if (fallback &&
+				    strequal(client_realm, server_realm)) {
+					goto init_sec_context_done;
+				}
+#endif /* !SAMBA4_USES_HEIMDAL */
+
+				nt_status = gensec_gssapi_setup_server_principal(gensec_gssapi_state,
+										 target_principal,
+										 service,
+										 hostname,
+										 server_realm,
+										 gensec_gssapi_state->gss_oid,
+										 &gensec_gssapi_state->target_principal,
+										 &gensec_gssapi_state->server_name);
+				if (!NT_STATUS_IS_OK(nt_status)) {
+					return nt_status;
+				}
+			}
+
+			maj_stat = gss_init_sec_context(&min_stat, 
+							gensec_gssapi_state->client_cred->creds,
+							&gensec_gssapi_state->gssapi_context, 
+							gensec_gssapi_state->server_name, 
+							gensec_gssapi_state->gss_oid,
+							gensec_gssapi_state->gss_want_flags, 
+							time_req,
+							gensec_gssapi_state->input_chan_bindings,
+							&input_token, 
+							&gss_oid_p,
+							&output_token, 
+							&gensec_gssapi_state->gss_got_flags, /* ret flags */
+							&time_rec);
+			goto init_sec_context_done;
+			/* JUMP! */
+init_sec_context_done:
+			if (gss_oid_p) {
+				gensec_gssapi_state->gss_oid = gss_oid_p;
+			}
+
+#ifdef SAMBA4_USES_HEIMDAL
+			send_to_kdc.func = smb_krb5_send_and_recv_func;
+			send_to_kdc.ptr = NULL;
+
+			ret = gsskrb5_set_send_to_kdc(&send_to_kdc);
+			if (ret) {
+				DEBUG(1,("gensec_gssapi_update: gsskrb5_set_send_to_kdc failed\n"));
+				return NT_STATUS_INTERNAL_ERROR;
+			}
+#endif
+			break;
+		}
+		case GENSEC_SERVER:
+		{
+			maj_stat = gss_accept_sec_context(&min_stat, 
+							  &gensec_gssapi_state->gssapi_context, 
+							  gensec_gssapi_state->server_cred->creds,
+							  &input_token, 
+							  gensec_gssapi_state->input_chan_bindings,
+							  &gensec_gssapi_state->client_name, 
+							  &gss_oid_p,
+							  &output_token, 
+							  &gensec_gssapi_state->gss_got_flags, 
+							  &time_rec,
+							  &gensec_gssapi_state->delegated_cred_handle);
+			if (gss_oid_p) {
+				gensec_gssapi_state->gss_oid = gss_oid_p;
+			}
+			break;
+		}
+		default:
+			return NT_STATUS_INVALID_PARAMETER;
+			
+		}
+
+		gensec_gssapi_state->gss_exchange_count++;
+
+		if (maj_stat == GSS_S_COMPLETE) {
+			*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
+			gss_release_buffer(&min_stat2, &output_token);
+			
+			if (gensec_gssapi_state->gss_got_flags & GSS_C_DELEG_FLAG &&
+			    gensec_gssapi_state->delegated_cred_handle != GSS_C_NO_CREDENTIAL) {
+				DEBUG(5, ("gensec_gssapi: credentials were delegated\n"));
+			} else {
+				DEBUG(5, ("gensec_gssapi: NO credentials were delegated\n"));
+			}
+
+			tv = timeval_current_ofs(time_rec, 0);
+			gensec_gssapi_state->expire_time = timeval_to_nttime(&tv);
+
+			/* We may have been invoked as SASL, so there
+			 * is more work to do */
+			if (gensec_gssapi_state->sasl) {
+				gensec_gssapi_state->sasl_state = STAGE_SASL_SSF_NEG;
+				return NT_STATUS_MORE_PROCESSING_REQUIRED;
+			} else {
+				gensec_gssapi_state->sasl_state = STAGE_DONE;
+
+				if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+					DEBUG(5, ("GSSAPI Connection will be cryptographically sealed\n"));
+				} else if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
+					DEBUG(5, ("GSSAPI Connection will be cryptographically signed\n"));
+				} else {
+					DEBUG(5, ("GSSAPI Connection will have no cryptographic protection\n"));
+				}
+
+				return NT_STATUS_OK;
+			}
+		} else if (maj_stat == GSS_S_CONTINUE_NEEDED) {
+			*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
+			gss_release_buffer(&min_stat2, &output_token);
+			
+			return NT_STATUS_MORE_PROCESSING_REQUIRED;
+		} else if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
+			gss_cred_id_t creds = NULL;
+			gss_name_t name;
+			gss_buffer_desc buffer;
+			OM_uint32 lifetime = 0;
+			gss_cred_usage_t usage;
+			const char *role = NULL;
+
+			switch (gensec_security->gensec_role) {
+			case GENSEC_CLIENT:
+				creds = gensec_gssapi_state->client_cred->creds;
+				role = "client";
+				break;
+			case GENSEC_SERVER:
+				creds = gensec_gssapi_state->server_cred->creds;
+				role = "server";
+				break;
+			}
+
+			DBG_ERR("GSS %s Update(krb5)(%d) failed, credentials "
+				"expired during GSSAPI handshake!\n",
+				role,
+				gensec_gssapi_state->gss_exchange_count);
+
+			maj_stat = gss_inquire_cred(&min_stat, 
+						    creds,
+						    &name, &lifetime, &usage, NULL);
+
+			if (maj_stat == GSS_S_COMPLETE) {
+				const char *usage_string = NULL;
+				switch (usage) {
+				case GSS_C_BOTH:
+					usage_string = "GSS_C_BOTH";
+					break;
+				case GSS_C_ACCEPT:
+					usage_string = "GSS_C_ACCEPT";
+					break;
+				case GSS_C_INITIATE:
+					usage_string = "GSS_C_INITIATE";
+					break;
+				}
+				maj_stat = gss_display_name(&min_stat, name, &buffer, NULL);
+				if (maj_stat) {
+					buffer.value = NULL;
+					buffer.length = 0;
+				}
+				if (lifetime > 0) {
+					DEBUG(0, ("GSSAPI gss_inquire_cred indicates expiry of %*.*s in %u sec for %s\n", 
+						  (int)buffer.length, (int)buffer.length, (char *)buffer.value, 
+						  lifetime, usage_string));
+				} else {
+					DEBUG(0, ("GSSAPI gss_inquire_cred indicates %*.*s has already expired for %s\n", 
+						  (int)buffer.length, (int)buffer.length, (char *)buffer.value, 
+						  usage_string));
+				}
+				gss_release_buffer(&min_stat, &buffer);
+				gss_release_name(&min_stat, &name);
+			} else if (maj_stat != GSS_S_COMPLETE) {
+				DEBUG(0, ("inquiry of credential lifetime via GSSAPI gss_inquire_cred failed: %s\n",
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+			}
+			return NT_STATUS_INVALID_PARAMETER;
+		} else if (smb_gss_oid_equal(gensec_gssapi_state->gss_oid,
+					     gss_mech_krb5)) {
+			switch (min_stat) {
+			case (OM_uint32)KRB5KRB_AP_ERR_TKT_NYV:
+				DEBUG(1, ("Error with ticket to contact %s: possible clock skew between us and the KDC or target server: %s\n",
+					  gensec_gssapi_state->target_principal,
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_TIME_DIFFERENCE_AT_DC; /* Make SPNEGO ignore us, we can't go any further here */
+			case (OM_uint32)KRB5KRB_AP_ERR_TKT_EXPIRED:
+				DEBUG(1, ("Error with ticket to contact %s: ticket is expired, possible clock skew between us and the KDC or target server: %s\n",
+					  gensec_gssapi_state->target_principal,
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
+			case (OM_uint32)KRB5_KDC_UNREACH:
+				DEBUG(3, ("Cannot reach a KDC we require in order to obtain a ticket to %s: %s\n",
+					  gensec_gssapi_state->target_principal,
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_NO_LOGON_SERVERS; /* Make SPNEGO ignore us, we can't go any further here */
+			case (OM_uint32)KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
+				DEBUG(3, ("Server %s is not registered with our KDC: %s\n",
+					  gensec_gssapi_state->target_principal,
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
+			case (OM_uint32)KRB5KRB_AP_ERR_MSG_TYPE:
+				/* garbage input, possibly from the auto-mech detection */
+				return NT_STATUS_INVALID_PARAMETER;
+			default:
+				DEBUG(1, ("GSS %s Update(krb5)(%d) Update failed: %s\n",
+					  gensec_security->gensec_role == GENSEC_CLIENT ? "client" : "server",
+					  gensec_gssapi_state->gss_exchange_count,
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_LOGON_FAILURE;
+			}
+		} else {
+			DEBUG(1, ("GSS %s Update(%d) failed: %s\n",
+				  gensec_security->gensec_role == GENSEC_CLIENT ? "client" : "server",
+				  gensec_gssapi_state->gss_exchange_count,
+				  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+			return NT_STATUS_LOGON_FAILURE;
+		}
+		break;
+	}
+
+	/* These last two stages are only done if we were invoked as SASL */
+	case STAGE_SASL_SSF_NEG:
+	{
+		switch (gensec_security->gensec_role) {
+		case GENSEC_CLIENT:
+		{
+			uint8_t maxlength_proposed[4]; 
+			uint8_t maxlength_accepted[4]; 
+			uint8_t security_supported;
+			int conf_state;
+			gss_qop_t qop_state;
+			input_token.length = in.length;
+			input_token.value = in.data;
+
+			/* As a client, we have just send a
+			 * zero-length blob to the server (after the
+			 * normal GSSAPI exchange), and it has replied
+			 * with it's SASL negotiation */
+			
+			maj_stat = gss_unwrap(&min_stat, 
+					      gensec_gssapi_state->gssapi_context, 
+					      &input_token,
+					      &output_token, 
+					      &conf_state,
+					      &qop_state);
+			if (GSS_ERROR(maj_stat)) {
+				DEBUG(1, ("gensec_gssapi_update: GSS UnWrap of SASL protection negotiation failed: %s\n", 
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_ACCESS_DENIED;
+			}
+			
+			if (output_token.length < 4) {
+				gss_release_buffer(&min_stat, &output_token);
+				return NT_STATUS_INVALID_PARAMETER;
+			}
+
+			memcpy(maxlength_proposed, output_token.value, 4);
+			gss_release_buffer(&min_stat, &output_token);
+
+			/* first byte is the proposed security */
+			security_supported = maxlength_proposed[0];
+			maxlength_proposed[0] = '\0';
+			
+			/* Rest is the proposed max wrap length */
+			gensec_gssapi_state->max_wrap_buf_size = MIN(RIVAL(maxlength_proposed, 0), 
+								     gensec_gssapi_state->max_wrap_buf_size);
+			gensec_gssapi_state->sasl_protection = 0;
+			if (security_supported & NEG_SEAL) {
+				if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+					gensec_gssapi_state->sasl_protection |= NEG_SEAL;
+				}
+			}
+			if (security_supported & NEG_SIGN) {
+				if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
+					gensec_gssapi_state->sasl_protection |= NEG_SIGN;
+				}
+			}
+			if (security_supported & NEG_NONE) {
+				gensec_gssapi_state->sasl_protection |= NEG_NONE;
+			}
+			if (gensec_gssapi_state->sasl_protection == 0) {
+				DEBUG(1, ("Remote server does not support unprotected connections\n"));
+				return NT_STATUS_ACCESS_DENIED;
+			}
+
+			/* Send back the negotiated max length */
+
+			RSIVAL(maxlength_accepted, 0, gensec_gssapi_state->max_wrap_buf_size);
+
+			maxlength_accepted[0] = gensec_gssapi_state->sasl_protection;
+			
+			input_token.value = maxlength_accepted;
+			input_token.length = sizeof(maxlength_accepted);
+
+			maj_stat = gss_wrap(&min_stat, 
+					    gensec_gssapi_state->gssapi_context, 
+					    false,
+					    GSS_C_QOP_DEFAULT,
+					    &input_token,
+					    &conf_state,
+					    &output_token);
+			if (GSS_ERROR(maj_stat)) {
+				DEBUG(1, ("GSS Update(SSF_NEG): GSS Wrap failed: %s\n", 
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_ACCESS_DENIED;
+			}
+			
+			*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
+			gss_release_buffer(&min_stat, &output_token);
+
+			/* quirk:  This changes the value that gensec_have_feature returns, to be that after SASL negotiation */
+			gensec_gssapi_state->sasl_state = STAGE_DONE;
+
+			if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+				DEBUG(3, ("SASL/GSSAPI Connection to server will be cryptographically sealed\n"));
+			} else if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
+				DEBUG(3, ("SASL/GSSAPI Connection to server will be cryptographically signed\n"));
+			} else {
+				DEBUG(3, ("SASL/GSSAPI Connection to server will have no cryptographic protection\n"));
+			}
+
+			return NT_STATUS_OK;
+		}
+		case GENSEC_SERVER:
+		{
+			uint8_t maxlength_proposed[4]; 
+			uint8_t security_supported = 0x0;
+			int conf_state;
+
+			/* As a server, we have just been sent a zero-length blob (note this, but it isn't fatal) */
+			if (in.length != 0) {
+				DEBUG(1, ("SASL/GSSAPI: client sent non-zero length starting SASL negotiation!\n"));
+			}
+			
+			/* Give the client some idea what we will support */
+			  
+			RSIVAL(maxlength_proposed, 0, gensec_gssapi_state->max_wrap_buf_size);
+			/* first byte is the proposed security */
+			maxlength_proposed[0] = '\0';
+			
+			gensec_gssapi_state->sasl_protection = 0;
+			if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+				security_supported |= NEG_SEAL;
+			} 
+			if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
+				security_supported |= NEG_SIGN;
+			}
+			if (security_supported == 0) {
+				/* If we don't support anything, this must be 0 */
+				RSIVAL(maxlength_proposed, 0, 0x0);
+			}
+
+			/* TODO:  We may not wish to support this */
+			security_supported |= NEG_NONE;
+			maxlength_proposed[0] = security_supported;
+			
+			input_token.value = maxlength_proposed;
+			input_token.length = sizeof(maxlength_proposed);
+
+			maj_stat = gss_wrap(&min_stat, 
+					    gensec_gssapi_state->gssapi_context, 
+					    false,
+					    GSS_C_QOP_DEFAULT,
+					    &input_token,
+					    &conf_state,
+					    &output_token);
+			if (GSS_ERROR(maj_stat)) {
+				DEBUG(1, ("GSS Update(SSF_NEG): GSS Wrap failed: %s\n", 
+					  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+				return NT_STATUS_ACCESS_DENIED;
+			}
+			
+			*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
+			gss_release_buffer(&min_stat, &output_token);
+
+			gensec_gssapi_state->sasl_state = STAGE_SASL_SSF_ACCEPT;
+			return NT_STATUS_MORE_PROCESSING_REQUIRED;
+		}
+		default:
+  			return NT_STATUS_INVALID_PARAMETER;
+			
+		}
+	}
+	/* This is s server-only stage */
+	case STAGE_SASL_SSF_ACCEPT:
+	{
+		uint8_t maxlength_accepted[4]; 
+		uint8_t security_accepted;
+		int conf_state;
+		gss_qop_t qop_state;
+		input_token.length = in.length;
+		input_token.value = in.data;
+			
+		maj_stat = gss_unwrap(&min_stat, 
+				      gensec_gssapi_state->gssapi_context, 
+				      &input_token,
+				      &output_token, 
+				      &conf_state,
+				      &qop_state);
+		if (GSS_ERROR(maj_stat)) {
+			DEBUG(1, ("gensec_gssapi_update: GSS UnWrap of SASL protection negotiation failed: %s\n", 
+				  gssapi_error_string(out_mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+			return NT_STATUS_ACCESS_DENIED;
+		}
+			
+		if (output_token.length < 4) {
+			gss_release_buffer(&min_stat, &output_token);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		memcpy(maxlength_accepted, output_token.value, 4);
+		gss_release_buffer(&min_stat, &output_token);
+		
+		/* first byte is the proposed security */
+		security_accepted = maxlength_accepted[0];
+		maxlength_accepted[0] = '\0';
+
+		/* Rest is the proposed max wrap length */
+		gensec_gssapi_state->max_wrap_buf_size = MIN(RIVAL(maxlength_accepted, 0), 
+							     gensec_gssapi_state->max_wrap_buf_size);
+
+		gensec_gssapi_state->sasl_protection = 0;
+		if (security_accepted & NEG_SEAL) {
+			if (!gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+				DEBUG(1, ("Remote client wanted seal, but gensec refused\n"));
+				return NT_STATUS_ACCESS_DENIED;
+			}
+			gensec_gssapi_state->sasl_protection |= NEG_SEAL;
+		}
+		if (security_accepted & NEG_SIGN) {
+			if (!gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
+				DEBUG(1, ("Remote client wanted sign, but gensec refused\n"));
+				return NT_STATUS_ACCESS_DENIED;
+			}
+			gensec_gssapi_state->sasl_protection |= NEG_SIGN;
+		}
+		if (security_accepted & NEG_NONE) {
+			gensec_gssapi_state->sasl_protection |= NEG_NONE;
+		}
+
+		/* quirk:  This changes the value that gensec_have_feature returns, to be that after SASL negotiation */
+		gensec_gssapi_state->sasl_state = STAGE_DONE;
+		if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+			DEBUG(5, ("SASL/GSSAPI Connection from client will be cryptographically sealed\n"));
+		} else if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
+			DEBUG(5, ("SASL/GSSAPI Connection from client will be cryptographically signed\n"));
+		} else {
+			DEBUG(5, ("SASL/GSSAPI Connection from client will have no cryptographic protection\n"));
+		}
+
+		*out = data_blob(NULL, 0);
+		return NT_STATUS_OK;	
+	}
+	default:
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+}
+
+struct gensec_gssapi_update_state {
+	NTSTATUS status;
+	DATA_BLOB out;
+};
+
+static struct tevent_req *gensec_gssapi_update_send(TALLOC_CTX *mem_ctx,
+						    struct tevent_context *ev,
+						    struct gensec_security *gensec_security,
+						    const DATA_BLOB in)
+{
+	struct tevent_req *req = NULL;
+	struct gensec_gssapi_update_state *state = NULL;
+	NTSTATUS status;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct gensec_gssapi_update_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	status = gensec_gssapi_update_internal(gensec_security,
+					       state, ev, in,
+					       &state->out);
+	state->status = status;
+	if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		tevent_req_done(req);
+		return tevent_req_post(req, ev);
+	}
+	if (tevent_req_nterror(req, status)) {
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_done(req);
+	return tevent_req_post(req, ev);
+}
+
+static NTSTATUS gensec_gssapi_update_recv(struct tevent_req *req,
+					  TALLOC_CTX *out_mem_ctx,
+					  DATA_BLOB *out)
+{
+	struct gensec_gssapi_update_state *state =
+		tevent_req_data(req,
+		struct gensec_gssapi_update_state);
+	NTSTATUS status;
+
+	*out = data_blob_null;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+
+	*out = state->out;
+	talloc_steal(out_mem_ctx, state->out.data);
+	status = state->status;
+	tevent_req_received(req);
+	return status;
+}
+
+static NTSTATUS gensec_gssapi_wrap(struct gensec_security *gensec_security, 
+				   TALLOC_CTX *mem_ctx, 
+				   const DATA_BLOB *in, 
+				   DATA_BLOB *out)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	OM_uint32 maj_stat, min_stat;
+	gss_buffer_desc input_token, output_token;
+	int conf_state;
+	input_token.length = in->length;
+	input_token.value = in->data;
+
+	maj_stat = gss_wrap(&min_stat, 
+			    gensec_gssapi_state->gssapi_context, 
+			    gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
+			    GSS_C_QOP_DEFAULT,
+			    &input_token,
+			    &conf_state,
+			    &output_token);
+	if (GSS_ERROR(maj_stat)) {
+		DEBUG(1, ("gensec_gssapi_wrap: GSS Wrap failed: %s\n", 
+			  gssapi_error_string(mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	*out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
+	gss_release_buffer(&min_stat, &output_token);
+
+	if (gensec_gssapi_state->sasl) {
+		size_t max_wrapped_size = gensec_gssapi_max_wrapped_size(gensec_security);
+		if (max_wrapped_size < out->length) {
+			DEBUG(1, ("gensec_gssapi_wrap: when wrapped, INPUT data (%u) is grew to be larger than SASL negotiated maximum output size (%u > %u)\n",
+				  (unsigned)in->length, 
+				  (unsigned)out->length, 
+				  (unsigned int)max_wrapped_size));
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+	}
+	
+	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
+	    && !conf_state) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_unwrap(struct gensec_security *gensec_security, 
+				     TALLOC_CTX *mem_ctx, 
+				     const DATA_BLOB *in, 
+				     DATA_BLOB *out)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	OM_uint32 maj_stat, min_stat;
+	gss_buffer_desc input_token, output_token;
+	int conf_state;
+	gss_qop_t qop_state;
+	input_token.length = in->length;
+	input_token.value = in->data;
+	
+	if (gensec_gssapi_state->sasl) {
+		size_t max_wrapped_size = gensec_gssapi_max_wrapped_size(gensec_security);
+		if (max_wrapped_size < in->length) {
+			DEBUG(1, ("gensec_gssapi_unwrap: WRAPPED data is larger than SASL negotiated maximum size\n"));
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+	}
+	
+	/*
+	 * FIXME: input_message_buffer is marked const, but gss_unwrap() may
+	 * modify it (see calls to rrc_rotate() in _gssapi_unwrap_cfx()).
+	 */
+	maj_stat = gss_unwrap(&min_stat, 
+			      gensec_gssapi_state->gssapi_context, 
+			      &input_token,
+			      &output_token, 
+			      &conf_state,
+			      &qop_state);
+	if (GSS_ERROR(maj_stat)) {
+		DEBUG(1, ("gensec_gssapi_unwrap: GSS UnWrap failed: %s\n", 
+			  gssapi_error_string(mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	*out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
+	gss_release_buffer(&min_stat, &output_token);
+	
+	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
+	    && !conf_state) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+	return NT_STATUS_OK;
+}
+
+/* Find out the maximum input size negotiated on this connection */
+
+static size_t gensec_gssapi_max_input_size(struct gensec_security *gensec_security) 
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	OM_uint32 maj_stat, min_stat;
+	OM_uint32 max_input_size;
+
+	maj_stat = gss_wrap_size_limit(&min_stat, 
+				       gensec_gssapi_state->gssapi_context,
+				       gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
+				       GSS_C_QOP_DEFAULT,
+				       gensec_gssapi_state->max_wrap_buf_size,
+				       &max_input_size);
+	if (GSS_ERROR(maj_stat)) {
+		TALLOC_CTX *mem_ctx = talloc_new(NULL); 
+		DEBUG(1, ("gensec_gssapi_max_input_size: determining signature size with gss_wrap_size_limit failed: %s\n",
+			  gssapi_error_string(mem_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+		talloc_free(mem_ctx);
+		return 0;
+	}
+
+	return max_input_size;
+}
+
+/* Find out the maximum output size negotiated on this connection */
+static size_t gensec_gssapi_max_wrapped_size(struct gensec_security *gensec_security) 
+{
+	struct gensec_gssapi_state *gensec_gssapi_state = talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);;
+	return gensec_gssapi_state->max_wrap_buf_size;
+}
+
+static NTSTATUS gensec_gssapi_seal_packet(struct gensec_security *gensec_security, 
+					  TALLOC_CTX *mem_ctx, 
+					  uint8_t *data, size_t length, 
+					  const uint8_t *whole_pdu, size_t pdu_length, 
+					  DATA_BLOB *sig)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	bool hdr_signing = false;
+	size_t sig_size = 0;
+	NTSTATUS status;
+
+	if (gensec_security->want_features & GENSEC_FEATURE_SIGN_PKT_HEADER) {
+		hdr_signing = true;
+	}
+
+	sig_size = gensec_gssapi_sig_size(gensec_security, length);
+
+	status = gssapi_seal_packet(gensec_gssapi_state->gssapi_context,
+				    gensec_gssapi_state->gss_oid,
+				    hdr_signing, sig_size,
+				    data, length,
+				    whole_pdu, pdu_length,
+				    mem_ctx, sig);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("gssapi_seal_packet(hdr_signing=%u,sig_size=%zu,"
+			  "data=%zu,pdu=%zu) failed: %s\n",
+			  hdr_signing, sig_size, length, pdu_length,
+			  nt_errstr(status)));
+		return status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_unseal_packet(struct gensec_security *gensec_security, 
+					    uint8_t *data, size_t length, 
+					    const uint8_t *whole_pdu, size_t pdu_length,
+					    const DATA_BLOB *sig)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	bool hdr_signing = false;
+	NTSTATUS status;
+
+	if (gensec_security->want_features & GENSEC_FEATURE_SIGN_PKT_HEADER) {
+		hdr_signing = true;
+	}
+
+	status = gssapi_unseal_packet(gensec_gssapi_state->gssapi_context,
+				      gensec_gssapi_state->gss_oid,
+				      hdr_signing,
+				      data, length,
+				      whole_pdu, pdu_length,
+				      sig);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("gssapi_unseal_packet(hdr_signing=%u,sig_size=%zu,"
+			  "data=%zu,pdu=%zu) failed: %s\n",
+			  hdr_signing, sig->length, length, pdu_length,
+			  nt_errstr(status)));
+		return status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_sign_packet(struct gensec_security *gensec_security, 
+					  TALLOC_CTX *mem_ctx, 
+					  const uint8_t *data, size_t length, 
+					  const uint8_t *whole_pdu, size_t pdu_length, 
+					  DATA_BLOB *sig)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	bool hdr_signing = false;
+	NTSTATUS status;
+
+	if (gensec_security->want_features & GENSEC_FEATURE_SIGN_PKT_HEADER) {
+		hdr_signing = true;
+	}
+
+	status = gssapi_sign_packet(gensec_gssapi_state->gssapi_context,
+				    gensec_gssapi_state->gss_oid,
+				    hdr_signing,
+				    data, length,
+				    whole_pdu, pdu_length,
+				    mem_ctx, sig);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("gssapi_sign_packet(hdr_signing=%u,"
+			  "data=%zu,pdu=%zu) failed: %s\n",
+			  hdr_signing, length, pdu_length,
+			  nt_errstr(status)));
+		return status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_gssapi_check_packet(struct gensec_security *gensec_security, 
+					   const uint8_t *data, size_t length, 
+					   const uint8_t *whole_pdu, size_t pdu_length, 
+					   const DATA_BLOB *sig)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	bool hdr_signing = false;
+	NTSTATUS status;
+
+	if (gensec_security->want_features & GENSEC_FEATURE_SIGN_PKT_HEADER) {
+		hdr_signing = true;
+	}
+
+	status = gssapi_check_packet(gensec_gssapi_state->gssapi_context,
+				     gensec_gssapi_state->gss_oid,
+				     hdr_signing,
+				     data, length,
+				     whole_pdu, pdu_length,
+				     sig);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("gssapi_check_packet(hdr_signing=%u,sig_size=%zu,"
+			  "data=%zu,pdu=%zu) failed: %s\n",
+			  hdr_signing, sig->length, length, pdu_length,
+			  nt_errstr(status)));
+		return status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+/* Try to figure out what features we actually got on the connection */
+static bool gensec_gssapi_have_feature(struct gensec_security *gensec_security, 
+				       uint32_t feature) 
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	if (feature & GENSEC_FEATURE_SIGN) {
+		/* If we are going GSSAPI SASL, then we honour the second negotiation */
+		if (gensec_gssapi_state->sasl 
+		    && gensec_gssapi_state->sasl_state == STAGE_DONE) {
+			return ((gensec_gssapi_state->sasl_protection & NEG_SIGN) 
+				&& (gensec_gssapi_state->gss_got_flags & GSS_C_INTEG_FLAG));
+		}
+		return gensec_gssapi_state->gss_got_flags & GSS_C_INTEG_FLAG;
+	}
+	if (feature & GENSEC_FEATURE_SEAL) {
+		/* If we are going GSSAPI SASL, then we honour the second negotiation */
+		if (gensec_gssapi_state->sasl 
+		    && gensec_gssapi_state->sasl_state == STAGE_DONE) {
+			return ((gensec_gssapi_state->sasl_protection & NEG_SEAL) 
+				 && (gensec_gssapi_state->gss_got_flags & GSS_C_CONF_FLAG));
+		}
+		return gensec_gssapi_state->gss_got_flags & GSS_C_CONF_FLAG;
+	}
+	if (feature & GENSEC_FEATURE_SESSION_KEY) {
+		/* Only for GSSAPI/Krb5 */
+		if (smb_gss_oid_equal(gensec_gssapi_state->gss_oid,
+				      gss_mech_krb5)) {
+			return true;
+		}
+	}
+	if (feature & GENSEC_FEATURE_DCE_STYLE) {
+		return gensec_gssapi_state->gss_got_flags & GSS_C_DCE_STYLE;
+	}
+	if (feature & GENSEC_FEATURE_NEW_SPNEGO) {
+		NTSTATUS status;
+		uint32_t keytype;
+
+		if (!(gensec_gssapi_state->gss_got_flags & GSS_C_INTEG_FLAG)) {
+			return false;
+		}
+
+		if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "force_new_spnego", false)) {
+			return true;
+		}
+		if (gensec_setting_bool(gensec_security->settings, "gensec_gssapi", "disable_new_spnego", false)) {
+			return false;
+		}
+
+		status = gssapi_get_session_key(gensec_gssapi_state,
+						gensec_gssapi_state->gssapi_context, NULL, &keytype);
+		/* 
+		 * We should do a proper sig on the mechListMic unless
+		 * we know we have to be backwards compatible with
+		 * earlier windows versions.  
+		 * 
+		 * Negotiating a non-krb5
+		 * mech for example should be regarded as having
+		 * NEW_SPNEGO
+		 */
+		if (NT_STATUS_IS_OK(status)) {
+			switch (keytype) {
+			case ENCTYPE_DES_CBC_CRC:
+			case ENCTYPE_DES_CBC_MD5:
+			case ENCTYPE_ARCFOUR_HMAC:
+			case ENCTYPE_DES3_CBC_SHA1:
+				return false;
+			}
+		}
+		return true;
+	}
+	/* We can always do async (rather than strict request/reply) packets.  */
+	if (feature & GENSEC_FEATURE_ASYNC_REPLIES) {
+		return true;
+	}
+	if (feature & GENSEC_FEATURE_SIGN_PKT_HEADER) {
+		return true;
+	}
+	return false;
+}
+
+static NTTIME gensec_gssapi_expire_time(struct gensec_security *gensec_security)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state =
+		talloc_get_type_abort(gensec_security->private_data,
+		struct gensec_gssapi_state);
+
+	return gensec_gssapi_state->expire_time;
+}
+
+/*
+ * Extract the 'session key' needed by SMB signing and ncacn_np
+ * (for encrypting some passwords).
+ * 
+ * This breaks all the abstractions, but what do you expect...
+ */
+static NTSTATUS gensec_gssapi_session_key(struct gensec_security *gensec_security, 
+					  TALLOC_CTX *mem_ctx,
+					  DATA_BLOB *session_key) 
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	return gssapi_get_session_key(mem_ctx, gensec_gssapi_state->gssapi_context, session_key, NULL);
+}
+
+/* Get some basic (and authorization) information about the user on
+ * this session.  This uses either the PAC (if present) or a local
+ * database lookup */
+static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_security,
+					   TALLOC_CTX *mem_ctx,
+					   struct auth_session_info **_session_info) 
+{
+	NTSTATUS nt_status;
+	TALLOC_CTX *tmp_ctx;
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	struct auth_session_info *session_info = NULL;
+	OM_uint32 maj_stat, min_stat;
+	DATA_BLOB pac_blob, *pac_blob_ptr = NULL;
+
+	gss_buffer_desc name_token;
+	char *principal_string;
+	
+	tmp_ctx = talloc_named(mem_ctx, 0, "gensec_gssapi_session_info context");
+	NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
+
+	maj_stat = gss_display_name (&min_stat,
+				     gensec_gssapi_state->client_name,
+				     &name_token,
+				     NULL);
+	if (GSS_ERROR(maj_stat)) {
+		DEBUG(1, ("GSS display_name failed: %s\n",
+			  gssapi_error_string(tmp_ctx, maj_stat, min_stat, gensec_gssapi_state->gss_oid)));
+		talloc_free(tmp_ctx);
+		return NT_STATUS_FOOBAR;
+	}
+
+	principal_string = talloc_strndup(tmp_ctx,
+					  (const char *)name_token.value,
+					  name_token.length);
+
+	gss_release_buffer(&min_stat, &name_token);
+
+	if (!principal_string) {
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	nt_status = gssapi_obtain_pac_blob(tmp_ctx,  gensec_gssapi_state->gssapi_context,
+					   gensec_gssapi_state->client_name,
+					   &pac_blob);
+	
+	/* IF we have the PAC - otherwise we need to get this
+	 * data from elsewhere - local ldb, or (TODO) lookup of some
+	 * kind... 
+	 */
+	if (NT_STATUS_IS_OK(nt_status)) {
+		pac_blob_ptr = &pac_blob;
+	}
+	nt_status = gensec_generate_session_info_pac(tmp_ctx,
+						     gensec_security,
+						     gensec_gssapi_state->smb_krb5_context,
+						     pac_blob_ptr, principal_string,
+						     gensec_get_remote_address(gensec_security),
+						     &session_info);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		talloc_free(tmp_ctx);
+		return nt_status;
+	}
+
+	nt_status = gensec_gssapi_session_key(gensec_security, session_info, &session_info->session_key);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		talloc_free(tmp_ctx);
+		return nt_status;
+	}
+
+	if (gensec_gssapi_state->gss_got_flags & GSS_C_DELEG_FLAG &&
+	    gensec_gssapi_state->delegated_cred_handle != GSS_C_NO_CREDENTIAL) {
+		krb5_error_code ret;
+		const char *error_string;
+
+		DEBUG(10, ("gensec_gssapi: delegated credentials supplied by client\n"));
+
+		/*
+		 * Create anonymous credentials for now.
+		 *
+		 * We will update them with the provided client gss creds.
+		 */
+		session_info->credentials = cli_credentials_init_anon(session_info);
+		if (session_info->credentials == NULL) {
+			talloc_free(tmp_ctx);
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		ret = cli_credentials_set_client_gss_creds(session_info->credentials, 
+							   gensec_security->settings->lp_ctx,
+							   gensec_gssapi_state->delegated_cred_handle,
+							   CRED_SPECIFIED, &error_string);
+		if (ret) {
+			talloc_free(tmp_ctx);
+			DEBUG(2,("Failed to get gss creds: %s\n", error_string));
+			return NT_STATUS_NO_MEMORY;
+		}
+		
+		/* This credential handle isn't useful for password authentication, so ensure nobody tries to do that */
+		cli_credentials_set_kerberos_state(session_info->credentials,
+						   CRED_USE_KERBEROS_REQUIRED,
+						   CRED_SPECIFIED);
+
+		/* It has been taken from this place... */
+		gensec_gssapi_state->delegated_cred_handle = GSS_C_NO_CREDENTIAL;
+	} else {
+		DEBUG(10, ("gensec_gssapi: NO delegated credentials supplied by client\n"));
+	}
+
+	*_session_info = talloc_steal(mem_ctx, session_info);
+	talloc_free(tmp_ctx);
+
+	return NT_STATUS_OK;
+}
+
+static size_t gensec_gssapi_sig_size(struct gensec_security *gensec_security, size_t data_size)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	size_t sig_size;
+
+	if (gensec_gssapi_state->sig_size > 0) {
+		return gensec_gssapi_state->sig_size;
+	}
+
+	sig_size = gssapi_get_sig_size(gensec_gssapi_state->gssapi_context,
+				       gensec_gssapi_state->gss_oid,
+				       gensec_gssapi_state->gss_got_flags,
+				       data_size);
+
+	gensec_gssapi_state->sig_size = sig_size;
+	return gensec_gssapi_state->sig_size;
+}
+
+static const char *gensec_gssapi_final_auth_type(struct gensec_security *gensec_security)
+{
+	struct gensec_gssapi_state *gensec_gssapi_state
+		= talloc_get_type(gensec_security->private_data, struct gensec_gssapi_state);
+	/* Only return the string for GSSAPI/Krb5 */
+	if (smb_gss_oid_equal(gensec_gssapi_state->gss_oid,
+			      gss_mech_krb5)) {
+		return GENSEC_FINAL_AUTH_TYPE_KRB5;
+	} else {
+		return "gensec_gssapi: UNKNOWN MECH";
+	}
+}
+
+static const char *gensec_gssapi_krb5_oids[] = { 
+	GENSEC_OID_KERBEROS5_OLD,
+	GENSEC_OID_KERBEROS5,
+	NULL 
+};
+
+static const char *gensec_gssapi_spnego_oids[] = { 
+	GENSEC_OID_SPNEGO,
+	NULL 
+};
+
+/* As a server, this could in theory accept any GSSAPI mech */
+static const struct gensec_security_ops gensec_gssapi_spnego_security_ops = {
+	.name		= "gssapi_spnego",
+	.sasl_name	= "GSS-SPNEGO",
+	.auth_type	= DCERPC_AUTH_TYPE_SPNEGO,
+	.oid            = gensec_gssapi_spnego_oids,
+	.client_start   = gensec_gssapi_client_start,
+	.server_start   = gensec_gssapi_server_start,
+	.magic  	= gensec_magic_check_krb5_oid,
+	.update_send	= gensec_gssapi_update_send,
+	.update_recv	= gensec_gssapi_update_recv,
+	.session_key	= gensec_gssapi_session_key,
+	.session_info	= gensec_gssapi_session_info,
+	.sign_packet	= gensec_gssapi_sign_packet,
+	.check_packet	= gensec_gssapi_check_packet,
+	.seal_packet	= gensec_gssapi_seal_packet,
+	.unseal_packet	= gensec_gssapi_unseal_packet,
+	.max_input_size	  = gensec_gssapi_max_input_size,
+	.max_wrapped_size = gensec_gssapi_max_wrapped_size,
+	.wrap           = gensec_gssapi_wrap,
+	.unwrap         = gensec_gssapi_unwrap,
+	.have_feature   = gensec_gssapi_have_feature,
+	.expire_time    = gensec_gssapi_expire_time,
+	.final_auth_type = gensec_gssapi_final_auth_type,
+	.enabled        = false,
+	.kerberos       = true,
+	.priority       = GENSEC_GSSAPI
+};
+
+/* As a server, this could in theory accept any GSSAPI mech */
+static const struct gensec_security_ops gensec_gssapi_krb5_security_ops = {
+	.name		= "gssapi_krb5",
+	.auth_type	= DCERPC_AUTH_TYPE_KRB5,
+	.oid            = gensec_gssapi_krb5_oids,
+	.client_start   = gensec_gssapi_client_start,
+	.server_start   = gensec_gssapi_server_start,
+	.magic  	= gensec_magic_check_krb5_oid,
+	.update_send	= gensec_gssapi_update_send,
+	.update_recv	= gensec_gssapi_update_recv,
+	.session_key	= gensec_gssapi_session_key,
+	.session_info	= gensec_gssapi_session_info,
+	.sig_size	= gensec_gssapi_sig_size,
+	.sign_packet	= gensec_gssapi_sign_packet,
+	.check_packet	= gensec_gssapi_check_packet,
+	.seal_packet	= gensec_gssapi_seal_packet,
+	.unseal_packet	= gensec_gssapi_unseal_packet,
+	.max_input_size	  = gensec_gssapi_max_input_size,
+	.max_wrapped_size = gensec_gssapi_max_wrapped_size,
+	.wrap           = gensec_gssapi_wrap,
+	.unwrap         = gensec_gssapi_unwrap,
+	.have_feature   = gensec_gssapi_have_feature,
+	.expire_time    = gensec_gssapi_expire_time,
+	.final_auth_type = gensec_gssapi_final_auth_type,
+	.enabled        = true,
+	.kerberos       = true,
+	.priority       = GENSEC_GSSAPI
+};
+
+/* As a server, this could in theory accept any GSSAPI mech */
+static const struct gensec_security_ops gensec_gssapi_sasl_krb5_security_ops = {
+	.name		  = "gssapi_krb5_sasl",
+	.sasl_name        = "GSSAPI",
+	.client_start     = gensec_gssapi_sasl_client_start,
+	.server_start     = gensec_gssapi_sasl_server_start,
+	.update_send      = gensec_gssapi_update_send,
+	.update_recv      = gensec_gssapi_update_recv,
+	.session_key	  = gensec_gssapi_session_key,
+	.session_info	  = gensec_gssapi_session_info,
+	.max_input_size	  = gensec_gssapi_max_input_size,
+	.max_wrapped_size = gensec_gssapi_max_wrapped_size,
+	.wrap             = gensec_gssapi_wrap,
+	.unwrap           = gensec_gssapi_unwrap,
+	.have_feature     = gensec_gssapi_have_feature,
+	.expire_time      = gensec_gssapi_expire_time,
+	.final_auth_type = gensec_gssapi_final_auth_type,
+	.enabled          = true,
+	.kerberos         = true,
+	.priority         = GENSEC_GSSAPI
+};
+
+_PUBLIC_ NTSTATUS gensec_gssapi_init(TALLOC_CTX *ctx)
+{
+	NTSTATUS ret;
+
+	ret = gensec_register(ctx, &gensec_gssapi_spnego_security_ops);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(0,("Failed to register '%s' gensec backend!\n",
+			gensec_gssapi_spnego_security_ops.name));
+		return ret;
+	}
+
+	ret = gensec_register(ctx, &gensec_gssapi_krb5_security_ops);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(0,("Failed to register '%s' gensec backend!\n",
+			gensec_gssapi_krb5_security_ops.name));
+		return ret;
+	}
+
+	ret = gensec_register(ctx, &gensec_gssapi_sasl_krb5_security_ops);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(0,("Failed to register '%s' gensec backend!\n",
+			gensec_gssapi_sasl_krb5_security_ops.name));
+		return ret;
+	}
+
+	return ret;
+}
diff --git a/source4/auth/gensec/gensec_gssapi.h b/source4/auth/gensec/gensec_gssapi.h
new file mode 100644
index 0000000..d788b5e
--- /dev/null
+++ b/source4/auth/gensec/gensec_gssapi.h
@@ -0,0 +1,69 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Kerberos backend for GENSEC
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
+   Copyright (C) Stefan Metzmacher <metze@samba.org> 2004-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* This structure described here, so the RPC-PAC test can get at the PAC provided */
+
+enum gensec_gssapi_sasl_state
+{
+	STAGE_GSS_NEG,
+	STAGE_SASL_SSF_NEG,
+	STAGE_SASL_SSF_ACCEPT,
+	STAGE_DONE
+};
+
+#define NEG_SEAL 0x4
+#define NEG_SIGN 0x2
+#define NEG_NONE 0x1
+
+struct gensec_gssapi_state {
+	gss_ctx_id_t gssapi_context;
+	gss_name_t server_name;
+	gss_name_t client_name;
+	OM_uint32 gss_want_flags, gss_got_flags;
+
+	gss_cred_id_t delegated_cred_handle;
+
+	NTTIME expire_time;
+
+	/* gensec_gssapi only */
+	gss_OID gss_oid;
+
+	struct gss_channel_bindings_struct *input_chan_bindings;
+	struct smb_krb5_context *smb_krb5_context;
+	struct gssapi_creds_container *client_cred;
+	struct gssapi_creds_container *server_cred;
+
+	bool sasl; /* We have two different mechs in this file: One
+		    * for SASL wrapped GSSAPI and another for normal
+		    * GSSAPI */
+	enum gensec_gssapi_sasl_state sasl_state;
+	uint8_t sasl_protection; /* What was negotiated at the SASL
+				  * layer, independent of the GSSAPI
+				  * layer... */
+
+	size_t max_wrap_buf_size;
+	int gss_exchange_count;
+	size_t sig_size;
+
+	char *target_principal;
+};
diff --git a/source4/auth/gensec/gensec_krb5.c b/source4/auth/gensec/gensec_krb5.c
new file mode 100644
index 0000000..5b4fd09
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5.c
@@ -0,0 +1,1133 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Kerberos backend for GENSEC
+   
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
+   Copyright (C) Andrew Tridgell 2001
+   Copyright (C) Luke Howard 2002-2003
+   Copyright (C) Stefan Metzmacher 2004-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include <tevent.h>
+#include "lib/util/tevent_ntstatus.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+#include "auth/auth.h"
+#include "lib/tsocket/tsocket.h"
+#include "librpc/gen_ndr/dcerpc.h"
+#include "auth/credentials/credentials.h"
+#include "auth/credentials/credentials_krb5.h"
+#include "auth/kerberos/kerberos_credentials.h"
+#include "auth/gensec/gensec.h"
+#include "auth/gensec/gensec_internal.h"
+#include "auth/gensec/gensec_proto.h"
+#include "auth/gensec/gensec_toplevel_proto.h"
+#include "param/param.h"
+#include "auth/auth_sam_reply.h"
+#include "lib/util/util_net.h"
+#include "../lib/util/asn1.h"
+#include "auth/kerberos/pac_utils.h"
+#include "gensec_krb5.h"
+#include "gensec_krb5_internal.h"
+#include "gensec_krb5_helpers.h"
+
+_PUBLIC_ NTSTATUS gensec_krb5_init(TALLOC_CTX *);
+
+static int gensec_krb5_destroy(struct gensec_krb5_state *gensec_krb5_state)
+{
+	if (!gensec_krb5_state->smb_krb5_context) {
+		/* We can't clean anything else up unless we started up this far */
+		return 0;
+	}
+	if (gensec_krb5_state->enc_ticket.length) { 
+		smb_krb5_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
+					    &gensec_krb5_state->enc_ticket); 
+	}
+
+	if (gensec_krb5_state->ticket) {
+		krb5_free_ticket(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				 gensec_krb5_state->ticket);
+	}
+
+	/* ccache freed in a child destructor */
+
+	krb5_free_keyblock(gensec_krb5_state->smb_krb5_context->krb5_context, 
+			   gensec_krb5_state->keyblock);
+		
+	if (gensec_krb5_state->auth_context) {
+		krb5_auth_con_free(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				   gensec_krb5_state->auth_context);
+	}
+
+	return 0;
+}
+
+static NTSTATUS gensec_krb5_start(struct gensec_security *gensec_security, bool gssapi)
+{
+	krb5_error_code ret;
+	struct gensec_krb5_state *gensec_krb5_state;
+	struct cli_credentials *creds;
+	const struct tsocket_address *tlocal_addr, *tremote_addr;
+	krb5_address my_krb5_addr, peer_krb5_addr;
+	
+	creds = gensec_get_credentials(gensec_security);
+	if (!creds) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	gensec_krb5_state = talloc_zero(gensec_security, struct gensec_krb5_state);
+	if (!gensec_krb5_state) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	gensec_security->private_data = gensec_krb5_state;
+	gensec_krb5_state->gssapi = gssapi;
+
+	talloc_set_destructor(gensec_krb5_state, gensec_krb5_destroy); 
+
+	if (cli_credentials_get_krb5_context(creds, 
+					     gensec_security->settings->lp_ctx, &gensec_krb5_state->smb_krb5_context)) {
+		talloc_free(gensec_krb5_state);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	ret = krb5_auth_con_init(gensec_krb5_state->smb_krb5_context->krb5_context, &gensec_krb5_state->auth_context);
+	if (ret) {
+		DEBUG(1,("gensec_krb5_start: krb5_auth_con_init failed (%s)\n", 
+			 smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, 
+						    ret, gensec_krb5_state)));
+		talloc_free(gensec_krb5_state);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	ret = krb5_auth_con_setflags(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				     gensec_krb5_state->auth_context,
+				     KRB5_AUTH_CONTEXT_DO_SEQUENCE);
+	if (ret) {
+		DEBUG(1,("gensec_krb5_start: krb5_auth_con_setflags failed (%s)\n", 
+			 smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, 
+						    ret, gensec_krb5_state)));
+		talloc_free(gensec_krb5_state);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	tlocal_addr = gensec_get_local_address(gensec_security);
+	if (tlocal_addr) {
+		ssize_t sockaddr_ret;
+		struct samba_sockaddr addr;
+		bool ok;
+
+		addr.sa_socklen = sizeof(addr.u);
+		sockaddr_ret = tsocket_address_bsd_sockaddr(
+			tlocal_addr, &addr.u.sa, addr.sa_socklen);
+		if (sockaddr_ret < 0) {
+			talloc_free(gensec_krb5_state);
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+		addr.sa_socklen = sockaddr_ret;
+		ok = smb_krb5_sockaddr_to_kaddr(&addr.u.ss, &my_krb5_addr);
+		if (!ok) {
+			DBG_WARNING("smb_krb5_sockaddr_to_kaddr (local) failed\n");
+			talloc_free(gensec_krb5_state);
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+	}
+
+	tremote_addr = gensec_get_remote_address(gensec_security);
+	if (tremote_addr) {
+		ssize_t sockaddr_ret;
+		struct samba_sockaddr addr;
+		bool ok;
+
+		addr.sa_socklen = sizeof(addr.u);
+		sockaddr_ret = tsocket_address_bsd_sockaddr(
+			tremote_addr, &addr.u.sa, addr.sa_socklen);
+		if (sockaddr_ret < 0) {
+			talloc_free(gensec_krb5_state);
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+		addr.sa_socklen = sockaddr_ret;
+		ok = smb_krb5_sockaddr_to_kaddr(&addr.u.ss, &peer_krb5_addr);
+		if (!ok) {
+			DBG_WARNING("smb_krb5_sockaddr_to_kaddr (remote) failed\n");
+			talloc_free(gensec_krb5_state);
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+	}
+
+	ret = krb5_auth_con_setaddrs(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				     gensec_krb5_state->auth_context,
+				     tlocal_addr ? &my_krb5_addr : NULL,
+				     tremote_addr ? &peer_krb5_addr : NULL);
+	if (ret) {
+		DEBUG(1,("gensec_krb5_start: krb5_auth_con_setaddrs failed (%s)\n", 
+			 smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, 
+						    ret, gensec_krb5_state)));
+		talloc_free(gensec_krb5_state);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_krb5_common_server_start(struct gensec_security *gensec_security, bool gssapi)
+{
+	NTSTATUS nt_status;
+	struct gensec_krb5_state *gensec_krb5_state;
+
+	nt_status = gensec_krb5_start(gensec_security, gssapi);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		return nt_status;
+	}
+	
+	gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	gensec_krb5_state->state_position = GENSEC_KRB5_SERVER_START;
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_krb5_server_start(struct gensec_security *gensec_security)
+{
+	return gensec_krb5_common_server_start(gensec_security, false);
+}
+
+static NTSTATUS gensec_fake_gssapi_krb5_server_start(struct gensec_security *gensec_security)
+{
+	return gensec_krb5_common_server_start(gensec_security, true);
+}
+
+static NTSTATUS gensec_krb5_common_client_start(struct gensec_security *gensec_security, bool gssapi)
+{
+	const char *hostname;
+	struct gensec_krb5_state *gensec_krb5_state;
+	NTSTATUS nt_status;
+	hostname = gensec_get_target_hostname(gensec_security);
+	if (!hostname) {
+		DEBUG(3, ("No hostname for target computer passed in, cannot use kerberos for this connection\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	if (is_ipaddress(hostname)) {
+		DEBUG(2, ("Cannot do krb5 to an IP address\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	if (strcmp(hostname, "localhost") == 0) {
+		DEBUG(2, ("krb5 to 'localhost' does not make sense\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+			
+	nt_status = gensec_krb5_start(gensec_security, gssapi);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		return nt_status;
+	}
+
+	gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_START;
+	gensec_krb5_state->ap_req_options = AP_OPTS_USE_SUBKEY;
+
+	if (gensec_krb5_state->gssapi) {
+		/* The Fake GSSAPI model emulates Samba3, which does not do mutual authentication */
+		if (gensec_setting_bool(gensec_security->settings, "gensec_fake_gssapi_krb5", "mutual", false)) {
+			gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
+		}
+	} else {
+		/* The wrapping for KPASSWD (a user of the raw KRB5 API) should be mutually authenticated */
+		if (gensec_setting_bool(gensec_security->settings, "gensec_krb5", "mutual", true)) {
+			gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
+		}
+	}
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_krb5_common_client_creds(struct gensec_security *gensec_security,
+						struct tevent_context *ev)
+{
+	struct gensec_krb5_state *gensec_krb5_state;
+	krb5_error_code ret;
+	struct ccache_container *ccache_container;
+	const char *error_string;
+	const char *principal;
+	const char *hostname;
+	krb5_data in_data = { .length = 0 };
+	krb5_data *in_data_p = NULL;
+#ifdef SAMBA4_USES_HEIMDAL
+	struct tevent_context *previous_ev;
+#endif
+
+	if (lpcfg_parm_bool(gensec_security->settings->lp_ctx,
+			    NULL, "gensec_krb5", "send_authenticator_checksum", true)) {
+		in_data_p = &in_data;
+	}
+	
+	gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+
+	principal = gensec_get_target_principal(gensec_security);
+	hostname = gensec_get_target_hostname(gensec_security);
+
+	ret = cli_credentials_get_ccache(gensec_get_credentials(gensec_security), 
+				         ev,
+					 gensec_security->settings->lp_ctx, &ccache_container, &error_string);
+	switch (ret) {
+	case 0:
+		break;
+	case KRB5KDC_ERR_PREAUTH_FAILED:
+	case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
+		return NT_STATUS_LOGON_FAILURE;
+	case KRB5_KDC_UNREACH:
+		DEBUG(3, ("Cannot reach a KDC we require to contact %s: %s\n", principal, error_string));
+		return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
+	case KRB5_CC_NOTFOUND:
+	case KRB5_CC_END:
+		DEBUG(3, ("Error preparing credentials we require to contact %s : %s\n", principal, error_string));
+		return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
+	default:
+		DEBUG(1, ("gensec_krb5_start: Acquiring initiator credentials failed: %s\n", error_string));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+	
+#ifdef SAMBA4_USES_HEIMDAL
+	/* Do this every time, in case we have weird recursive issues here */
+	ret = smb_krb5_context_set_event_ctx(gensec_krb5_state->smb_krb5_context, ev, &previous_ev);
+	if (ret != 0) {
+		DEBUG(1, ("gensec_krb5_start: Setting event context failed\n"));
+		return NT_STATUS_NO_MEMORY;
+	}
+#endif
+	if (principal) {
+		krb5_principal target_principal;
+		ret = krb5_parse_name(gensec_krb5_state->smb_krb5_context->krb5_context, principal,
+				      &target_principal);
+		if (ret == 0) {
+			krb5_creds this_cred;
+			krb5_creds *cred;
+
+			ZERO_STRUCT(this_cred);
+			ret = krb5_cc_get_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
+						    ccache_container->ccache,
+						    &this_cred.client);
+			if (ret != 0) {
+				krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
+						    target_principal);
+				return NT_STATUS_UNSUCCESSFUL;
+			}
+
+			ret = krb5_copy_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
+						  target_principal,
+						  &this_cred.server);
+			krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
+					    target_principal);
+			if (ret != 0) {
+				krb5_free_cred_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
+							&this_cred);
+				return NT_STATUS_UNSUCCESSFUL;
+			}
+			this_cred.times.endtime = 0;
+
+			ret = krb5_get_credentials(gensec_krb5_state->smb_krb5_context->krb5_context,
+						   0,
+						   ccache_container->ccache,
+						   &this_cred,
+						   &cred);
+			krb5_free_cred_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
+						&this_cred);
+			if (ret != 0) {
+				return NT_STATUS_UNSUCCESSFUL;
+			}
+
+			ret = krb5_mk_req_extended(gensec_krb5_state->smb_krb5_context->krb5_context,
+						   &gensec_krb5_state->auth_context,
+						   gensec_krb5_state->ap_req_options,
+						   in_data_p,
+						   cred,
+						   &gensec_krb5_state->enc_ticket);
+		}
+	} else {
+		ret = krb5_mk_req(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				  &gensec_krb5_state->auth_context,
+				  gensec_krb5_state->ap_req_options,
+				  discard_const_p(char, gensec_get_target_service(gensec_security)),
+				  discard_const_p(char, hostname),
+				  in_data_p, ccache_container->ccache, 
+				  &gensec_krb5_state->enc_ticket);
+	}
+
+#ifdef SAMBA4_USES_HEIMDAL
+	smb_krb5_context_remove_event_ctx(gensec_krb5_state->smb_krb5_context, previous_ev, ev);
+#endif
+
+	switch (ret) {
+	case 0:
+		return NT_STATUS_OK;
+	case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
+		DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n", 
+			  hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
+		return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
+	case KRB5_KDC_UNREACH:
+		DEBUG(3, ("Cannot reach a KDC we require to contact host [%s]: %s\n",
+			  hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
+		return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
+	case KRB5KDC_ERR_PREAUTH_FAILED:
+	case KRB5KRB_AP_ERR_TKT_EXPIRED:
+	case KRB5_CC_END:
+		/* Too much clock skew - we will need to kinit to re-skew the clock */
+	case KRB5KRB_AP_ERR_SKEW:
+	case KRB5_KDCREP_SKEW:
+		DEBUG(3, ("kerberos (mk_req) failed: %s\n", 
+			  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
+		FALL_THROUGH;
+	/* just don't print a message for these really ordinary messages */
+	case KRB5_FCC_NOFILE:
+	case KRB5_CC_NOTFOUND:
+	case ENOENT:
+		
+		return NT_STATUS_UNSUCCESSFUL;
+		break;
+		
+	default:
+		DEBUG(0, ("kerberos: %s\n", 
+			  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+}
+
+static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security)
+{
+	return gensec_krb5_common_client_start(gensec_security, false);
+}
+
+static NTSTATUS gensec_fake_gssapi_krb5_client_start(struct gensec_security *gensec_security)
+{
+	return gensec_krb5_common_client_start(gensec_security, true);
+}
+
+
+/*
+  generate a krb5 GSS-API wrapper packet given a ticket
+*/
+static DATA_BLOB gensec_gssapi_gen_krb5_wrap(TALLOC_CTX *mem_ctx, const DATA_BLOB *ticket, const uint8_t tok_id[2])
+{
+	struct asn1_data *data;
+	DATA_BLOB ret = data_blob_null;
+
+	data = asn1_init(mem_ctx, ASN1_MAX_TREE_DEPTH);
+	if (!data || !ticket->data) {
+		return ret;
+	}
+
+	if (!asn1_push_tag(data, ASN1_APPLICATION(0))) goto err;
+	if (!asn1_write_OID(data, GENSEC_OID_KERBEROS5)) goto err;
+
+	if (!asn1_write(data, tok_id, 2)) goto err;
+	if (!asn1_write(data, ticket->data, ticket->length)) goto err;
+	if (!asn1_pop_tag(data)) goto err;
+
+
+	if (!asn1_extract_blob(data, mem_ctx, &ret)) {
+		goto err;
+	}
+	asn1_free(data);
+
+	return ret;
+
+  err:
+
+	DEBUG(1, ("Failed to build krb5 wrapper at offset %d\n",
+		  (int)asn1_current_ofs(data)));
+	asn1_free(data);
+	return ret;
+}
+
+/*
+  parse a krb5 GSS-API wrapper packet giving a ticket
+*/
+static bool gensec_gssapi_parse_krb5_wrap(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob, DATA_BLOB *ticket, uint8_t tok_id[2])
+{
+	bool ret = false;
+	struct asn1_data *data = asn1_init(mem_ctx, ASN1_MAX_TREE_DEPTH);
+	int data_remaining;
+
+	if (!data) {
+		return false;
+	}
+
+	if (!asn1_load(data, *blob)) goto err;
+	if (!asn1_start_tag(data, ASN1_APPLICATION(0))) goto err;
+	if (!asn1_check_OID(data, GENSEC_OID_KERBEROS5)) goto err;
+
+	data_remaining = asn1_tag_remaining(data);
+
+	if (data_remaining < 3) {
+		asn1_set_error(data);
+	} else {
+		if (!asn1_read(data, tok_id, 2)) goto err;
+		data_remaining -= 2;
+		*ticket = data_blob_talloc(mem_ctx, NULL, data_remaining);
+		if (!asn1_read(data, ticket->data, ticket->length)) goto err;
+	}
+
+	if (!asn1_end_tag(data)) goto err;
+
+	ret = !asn1_has_error(data);
+
+  err:
+
+	asn1_free(data);
+
+	return ret;
+}
+
+static NTSTATUS gensec_krb5_update_internal(struct gensec_security *gensec_security,
+					    TALLOC_CTX *out_mem_ctx,
+					    struct tevent_context *ev,
+					    const DATA_BLOB in, DATA_BLOB *out)
+{
+	struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	krb5_error_code ret = 0;
+	NTSTATUS nt_status;
+
+	switch (gensec_krb5_state->state_position) {
+	case GENSEC_KRB5_CLIENT_START:
+	{
+		DATA_BLOB unwrapped_out;
+		
+		nt_status = gensec_krb5_common_client_creds(gensec_security, ev);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			return nt_status;
+		}
+
+		if (gensec_krb5_state->gssapi) {
+			unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
+			
+			/* wrap that up in a nice GSS-API wrapping */
+			*out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
+		} else {
+			*out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
+		}
+		if (gensec_krb5_state->ap_req_options & AP_OPTS_MUTUAL_REQUIRED) {
+			gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
+			nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
+		} else {
+			gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
+			nt_status = NT_STATUS_OK;
+		}
+		return nt_status;
+	}
+		
+	case GENSEC_KRB5_CLIENT_MUTUAL_AUTH:
+	{
+		DATA_BLOB unwrapped_in;
+		krb5_data inbuf;
+		krb5_ap_rep_enc_part *repl = NULL;
+		uint8_t tok_id[2];
+
+		if (gensec_krb5_state->gssapi) {
+			if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
+				DEBUG(1,("gensec_gssapi_parse_krb5_wrap(mutual authentication) failed to parse\n"));
+				dump_data_pw("Mutual authentication message:\n", in.data, in.length);
+				return NT_STATUS_INVALID_PARAMETER;
+			}
+		} else {
+			unwrapped_in = in;
+		}
+		/* TODO: check the tok_id */
+
+		inbuf.data = (char *)unwrapped_in.data;
+		inbuf.length = unwrapped_in.length;
+		ret = krb5_rd_rep(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				  gensec_krb5_state->auth_context,
+				  &inbuf, &repl);
+		if (ret) {
+			DEBUG(1,("krb5_rd_rep (mutual authentication) failed (%s)\n",
+				 smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
+			dump_data_pw("Mutual authentication message:\n", (uint8_t *)inbuf.data, inbuf.length);
+			nt_status = NT_STATUS_ACCESS_DENIED;
+		} else {
+			*out = data_blob(NULL, 0);
+			nt_status = NT_STATUS_OK;
+			gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
+		}
+		if (repl) {
+			krb5_free_ap_rep_enc_part(gensec_krb5_state->smb_krb5_context->krb5_context, repl);
+		}
+		return nt_status;
+	}
+
+	case GENSEC_KRB5_SERVER_START:
+	{
+		DATA_BLOB unwrapped_in;
+		DATA_BLOB unwrapped_out = data_blob(NULL, 0);
+		krb5_data inbuf, outbuf;
+		uint8_t tok_id[2];
+		struct keytab_container *keytab;
+		krb5_principal server_in_keytab;
+		const char *error_string;
+		enum credentials_obtained obtained;
+
+		if (!in.data) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}	
+
+		/* Grab the keytab, however generated */
+		ret = cli_credentials_get_keytab(gensec_get_credentials(gensec_security), 
+						 gensec_security->settings->lp_ctx, &keytab);
+		if (ret) {
+			return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
+		}
+		
+		/* This ensures we lookup the correct entry in that
+		 * keytab.  A NULL principal is acceptable, and means
+		 * that the krb5 libs should search the keytab at
+		 * accept time for any matching key */
+		ret = principal_from_credentials(out_mem_ctx, gensec_get_credentials(gensec_security), 
+						 gensec_krb5_state->smb_krb5_context, 
+						 &server_in_keytab, &obtained, &error_string);
+
+		if (ret) {
+			DEBUG(2,("Failed to make credentials from principal: %s\n", error_string));
+			return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
+		}
+
+		if (keytab->password_based || obtained < CRED_SPECIFIED) {
+			/* 
+			 * Use match-by-key in this case (matches
+			 * cli_credentials_get_server_gss_creds()
+			 * behaviour).  No need to free the memory,
+			 * this is handled with a talloc destructor.
+			 */
+			server_in_keytab = NULL;
+		}
+
+		/* Parse the GSSAPI wrapping, if it's there... (win2k3 allows it to be omitted) */
+		if (gensec_krb5_state->gssapi
+		    && gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
+			inbuf.data = (char *)unwrapped_in.data;
+			inbuf.length = unwrapped_in.length;
+		} else {
+			inbuf.data = (char *)in.data;
+			inbuf.length = in.length;
+		}
+
+		ret = smb_krb5_rd_req_decoded(gensec_krb5_state->smb_krb5_context->krb5_context,
+					      &gensec_krb5_state->auth_context,
+					      &inbuf,
+					      keytab->keytab,
+					      server_in_keytab,
+					      &outbuf,
+					      &gensec_krb5_state->ticket,
+					      &gensec_krb5_state->keyblock);
+
+		if (ret) {
+			DBG_WARNING("smb_krb5_rd_req_decoded failed\n");
+			return NT_STATUS_LOGON_FAILURE;
+		}
+		unwrapped_out.data = (uint8_t *)outbuf.data;
+		unwrapped_out.length = outbuf.length;
+		gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
+		/* wrap that up in a nice GSS-API wrapping */
+		if (gensec_krb5_state->gssapi) {
+			*out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REP);
+		} else {
+			*out = data_blob_talloc(out_mem_ctx, outbuf.data, outbuf.length);
+		}
+		smb_krb5_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
+					    &outbuf);
+		return NT_STATUS_OK;
+	}
+
+	case GENSEC_KRB5_DONE:
+	default:
+		/* Asking too many times... */
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+}
+
+struct gensec_krb5_update_state {
+	NTSTATUS status;
+	DATA_BLOB out;
+};
+
+static struct tevent_req *gensec_krb5_update_send(TALLOC_CTX *mem_ctx,
+						  struct tevent_context *ev,
+						  struct gensec_security *gensec_security,
+						  const DATA_BLOB in)
+{
+	struct tevent_req *req = NULL;
+	struct gensec_krb5_update_state *state = NULL;
+	NTSTATUS status;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct gensec_krb5_update_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	status = gensec_krb5_update_internal(gensec_security,
+					     state, ev, in,
+					     &state->out);
+	state->status = status;
+	if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		tevent_req_done(req);
+		return tevent_req_post(req, ev);
+	}
+	if (tevent_req_nterror(req, status)) {
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_done(req);
+	return tevent_req_post(req, ev);
+}
+
+static NTSTATUS gensec_krb5_update_recv(struct tevent_req *req,
+					TALLOC_CTX *out_mem_ctx,
+					DATA_BLOB *out)
+{
+	struct gensec_krb5_update_state *state =
+		tevent_req_data(req,
+		struct gensec_krb5_update_state);
+	NTSTATUS status;
+
+	*out = data_blob_null;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+
+	*out = state->out;
+	talloc_steal(out_mem_ctx, state->out.data);
+	status = state->status;
+	tevent_req_received(req);
+	return status;
+}
+
+static NTSTATUS gensec_krb5_session_key(struct gensec_security *gensec_security, 
+					TALLOC_CTX *mem_ctx,
+					DATA_BLOB *session_key) 
+{
+	struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
+	krb5_auth_context auth_context = gensec_krb5_state->auth_context;
+	krb5_error_code err = -1;
+	bool remote = false;
+	bool ok;
+
+	if (gensec_krb5_state->state_position != GENSEC_KRB5_DONE) {
+		return NT_STATUS_NO_USER_SESSION_KEY;
+	}
+
+	switch (gensec_security->gensec_role) {
+	case GENSEC_CLIENT:
+		remote = false;
+		break;
+	case GENSEC_SERVER:
+		remote = true;
+		break;
+	}
+
+	ok = smb_krb5_get_smb_session_key(mem_ctx,
+					  context,
+					  auth_context,
+					  session_key,
+					  remote);
+	if (!ok) {
+		DEBUG(10, ("KRB5 error getting session key %d\n", err));
+		return NT_STATUS_NO_USER_SESSION_KEY;
+	}
+
+	return NT_STATUS_OK;
+}
+
+#ifdef SAMBA4_USES_HEIMDAL
+static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
+					 TALLOC_CTX *mem_ctx,
+					 struct auth_session_info **_session_info) 
+{
+	NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
+	struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
+	struct auth_session_info *session_info = NULL;
+
+	krb5_principal client_principal;
+	char *principal_string = NULL;
+	
+	DATA_BLOB pac_blob, *pac_blob_ptr = NULL;
+	krb5_data pac_data;
+
+	krb5_error_code ret;
+
+	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
+	if (!tmp_ctx) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	
+	ret = krb5_ticket_get_client(context, gensec_krb5_state->ticket, &client_principal);
+	if (ret) {
+		DEBUG(5, ("krb5_ticket_get_client failed to get client principal: %s\n", 
+			  smb_get_krb5_error_message(context, 
+						     ret, tmp_ctx)));
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+	
+	ret = krb5_unparse_name(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				client_principal, &principal_string);
+	if (ret) {
+		DEBUG(1, ("Unable to parse client principal: %s\n",
+			  smb_get_krb5_error_message(context, 
+						     ret, tmp_ctx)));
+		krb5_free_principal(context, client_principal);
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	ret = krb5_ticket_get_authorization_data_type(context, gensec_krb5_state->ticket, 
+						      KRB5_AUTHDATA_WIN2K_PAC, 
+						      &pac_data);
+	
+	if (ret) {
+		/* NO pac */
+		DEBUG(5, ("krb5_ticket_get_authorization_data_type failed to find PAC: %s\n", 
+			  smb_get_krb5_error_message(context, 
+						     ret, tmp_ctx)));
+	} else {
+		/* Found pac */
+		pac_blob = data_blob_talloc(tmp_ctx, pac_data.data, pac_data.length);
+		smb_krb5_free_data_contents(context, &pac_data);
+		if (!pac_blob.data) {
+			free(principal_string);
+			krb5_free_principal(context, client_principal);
+			talloc_free(tmp_ctx);
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		/* decode and verify the pac */
+		nt_status = kerberos_decode_pac(gensec_krb5_state,
+						pac_blob,
+						gensec_krb5_state->smb_krb5_context->krb5_context,
+						NULL, gensec_krb5_state->keyblock,
+						client_principal,
+						gensec_krb5_state->ticket->ticket.authtime, NULL);
+
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			free(principal_string);
+			krb5_free_principal(context, client_principal);
+			talloc_free(tmp_ctx);
+			return nt_status;
+		}
+
+		pac_blob_ptr = &pac_blob;
+	}
+
+	nt_status = gensec_generate_session_info_pac(tmp_ctx,
+						     gensec_security,
+						     gensec_krb5_state->smb_krb5_context,
+						     pac_blob_ptr, principal_string,
+						     gensec_get_remote_address(gensec_security),
+						     &session_info);
+
+	free(principal_string);
+	krb5_free_principal(context, client_principal);
+
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		talloc_free(tmp_ctx);
+		return nt_status;
+	}
+
+	nt_status = gensec_krb5_session_key(gensec_security, session_info, &session_info->session_key);
+
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		talloc_free(tmp_ctx);
+		return nt_status;
+	}
+
+	*_session_info = talloc_steal(mem_ctx, session_info);
+
+	talloc_free(tmp_ctx);
+	return NT_STATUS_OK;
+}
+#else /* MIT KERBEROS */
+static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
+					 TALLOC_CTX *mem_ctx,
+					 struct auth_session_info **psession_info)
+{
+	NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
+	struct gensec_krb5_state *gensec_krb5_state =
+		(struct gensec_krb5_state *)gensec_security->private_data;
+	krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
+	struct auth_session_info *session_info = NULL;
+
+	krb5_principal client_principal;
+	char *principal_string = NULL;
+
+	krb5_authdata **auth_pac_data = NULL;
+	DATA_BLOB pac_blob, *pac_blob_ptr = NULL;
+
+	krb5_error_code code;
+
+	TALLOC_CTX *tmp_ctx;
+
+	tmp_ctx = talloc_new(mem_ctx);
+	if (tmp_ctx == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	code = krb5_copy_principal(context,
+				   gensec_krb5_state->ticket->enc_part2->client,
+				   &client_principal);
+	if (code != 0) {
+		DBG_INFO("krb5_copy_principal failed to copy client "
+			 "principal: %s\n",
+			 smb_get_krb5_error_message(context, code, tmp_ctx));
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	code = krb5_unparse_name(context, client_principal, &principal_string);
+	if (code != 0) {
+		DBG_WARNING("Unable to parse client principal: %s\n",
+			    smb_get_krb5_error_message(context, code, tmp_ctx));
+		krb5_free_principal(context, client_principal);
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	code = krb5_find_authdata(context,
+				  gensec_krb5_state->ticket->enc_part2->authorization_data,
+				  NULL,
+				  KRB5_AUTHDATA_WIN2K_PAC,
+				  &auth_pac_data);
+	if (code != 0) {
+		/* NO pac */
+		DBG_INFO("krb5_find_authdata failed to find PAC: %s\n",
+			 smb_get_krb5_error_message(context, code, tmp_ctx));
+	} else {
+		krb5_timestamp ticket_authtime =
+			gensec_krb5_state->ticket->enc_part2->times.authtime;
+
+		/* Found pac */
+		pac_blob = data_blob_talloc(tmp_ctx,
+					    auth_pac_data[0]->contents,
+					    auth_pac_data[0]->length);
+		krb5_free_authdata(context, auth_pac_data);
+		if (pac_blob.data == NULL) {
+			free(principal_string);
+			krb5_free_principal(context, client_principal);
+			talloc_free(tmp_ctx);
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		/* decode and verify the pac */
+		status = kerberos_decode_pac(gensec_krb5_state,
+					     pac_blob,
+					     context,
+					     NULL,
+					     gensec_krb5_state->keyblock,
+					     client_principal,
+					     ticket_authtime,
+					     NULL);
+
+		if (!NT_STATUS_IS_OK(status)) {
+			free(principal_string);
+			krb5_free_principal(context, client_principal);
+			talloc_free(tmp_ctx);
+			return status;
+		}
+
+		pac_blob_ptr = &pac_blob;
+	}
+	krb5_free_principal(context, client_principal);
+
+	status = gensec_generate_session_info_pac(tmp_ctx,
+						  gensec_security,
+						  gensec_krb5_state->smb_krb5_context,
+						  pac_blob_ptr,
+						  principal_string,
+						  gensec_get_remote_address(gensec_security),
+						  &session_info);
+	SAFE_FREE(principal_string);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return status;
+	}
+
+	status = gensec_krb5_session_key(gensec_security,
+					 session_info,
+					 &session_info->session_key);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return status;
+	}
+
+	*psession_info = talloc_steal(mem_ctx, session_info);
+	talloc_free(tmp_ctx);
+
+	return NT_STATUS_OK;
+}
+#endif /* SAMBA4_USES_HEIMDAL */
+
+static NTSTATUS gensec_krb5_wrap(struct gensec_security *gensec_security, 
+				   TALLOC_CTX *mem_ctx, 
+				   const DATA_BLOB *in, 
+				   DATA_BLOB *out)
+{
+	struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
+	krb5_auth_context auth_context = gensec_krb5_state->auth_context;
+	krb5_error_code ret;
+	krb5_data input, output;
+	input.length = in->length;
+	input.data = (char *)in->data;
+	
+	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+		ret = krb5_mk_priv(context, auth_context, &input, &output, NULL);
+		if (ret) {
+			DEBUG(1, ("krb5_mk_priv failed: %s\n", 
+				  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, 
+							     ret, mem_ctx)));
+			return NT_STATUS_ACCESS_DENIED;
+		}
+		*out = data_blob_talloc(mem_ctx, output.data, output.length);
+		
+		smb_krb5_free_data_contents(context, &output);
+	} else {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_krb5_unwrap(struct gensec_security *gensec_security, 
+				     TALLOC_CTX *mem_ctx, 
+				     const DATA_BLOB *in, 
+				     DATA_BLOB *out)
+{
+	struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
+	krb5_auth_context auth_context = gensec_krb5_state->auth_context;
+	krb5_error_code ret;
+	krb5_data input, output;
+	krb5_replay_data replay;
+	input.length = in->length;
+	input.data = (char *)in->data;
+	
+	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+		ret = krb5_rd_priv(context, auth_context, &input, &output, &replay);
+		if (ret) {
+			DEBUG(1, ("krb5_rd_priv failed: %s\n", 
+				  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, 
+							     ret, mem_ctx)));
+			return NT_STATUS_ACCESS_DENIED;
+		}
+		*out = data_blob_talloc(mem_ctx, output.data, output.length);
+		
+		smb_krb5_free_data_contents(context, &output);
+	} else {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+	return NT_STATUS_OK;
+}
+
+static bool gensec_krb5_have_feature(struct gensec_security *gensec_security,
+				     uint32_t feature)
+{
+	struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
+	if (feature & GENSEC_FEATURE_SESSION_KEY) {
+		return true;
+	} 
+	if (gensec_krb5_state->gssapi) {
+		return false;
+	}
+
+	/*
+	 * krb5_mk_priv provides SIGN and SEAL
+	 */
+	if (feature & GENSEC_FEATURE_SIGN) {
+		return true;
+	}
+	if (feature & GENSEC_FEATURE_SEAL) {
+		return true;
+	}
+
+	return false;
+}
+
+static const char *gensec_krb5_final_auth_type(struct gensec_security *gensec_security)
+{
+	return GENSEC_FINAL_AUTH_TYPE_KRB5;
+}
+
+static const char *gensec_krb5_oids[] = { 
+	GENSEC_OID_KERBEROS5,
+	GENSEC_OID_KERBEROS5_OLD,
+	NULL 
+};
+
+static const struct gensec_security_ops gensec_fake_gssapi_krb5_security_ops = {
+	.name		= "fake_gssapi_krb5",
+	.auth_type	= DCERPC_AUTH_TYPE_KRB5,
+	.oid            = gensec_krb5_oids,
+	.client_start   = gensec_fake_gssapi_krb5_client_start,
+	.server_start   = gensec_fake_gssapi_krb5_server_start,
+	.update_send	= gensec_krb5_update_send,
+	.update_recv	= gensec_krb5_update_recv,
+	.magic   	= gensec_magic_check_krb5_oid,
+	.session_key	= gensec_krb5_session_key,
+	.session_info	= gensec_krb5_session_info,
+	.have_feature   = gensec_krb5_have_feature,
+	.final_auth_type = gensec_krb5_final_auth_type,
+	.enabled        = false,
+	.kerberos       = true,
+	.priority       = GENSEC_KRB5,
+};
+
+static const struct gensec_security_ops gensec_krb5_security_ops = {
+	.name		= "krb5",
+	.client_start   = gensec_krb5_client_start,
+	.server_start   = gensec_krb5_server_start,
+	.update_send	= gensec_krb5_update_send,
+	.update_recv	= gensec_krb5_update_recv,
+	.session_key	= gensec_krb5_session_key,
+	.session_info	= gensec_krb5_session_info,
+	.have_feature   = gensec_krb5_have_feature,
+	.wrap           = gensec_krb5_wrap,
+	.unwrap         = gensec_krb5_unwrap,
+	.final_auth_type = gensec_krb5_final_auth_type,
+	.enabled        = true,
+	.kerberos       = true,
+	.priority       = GENSEC_KRB5
+};
+
+_PUBLIC_ NTSTATUS gensec_krb5_init(TALLOC_CTX *ctx)
+{
+	NTSTATUS ret;
+
+	ret = gensec_register(ctx, &gensec_krb5_security_ops);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(0,("Failed to register '%s' gensec backend!\n",
+			gensec_krb5_security_ops.name));
+		return ret;
+	}
+
+	ret = gensec_register(ctx, &gensec_fake_gssapi_krb5_security_ops);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(0,("Failed to register '%s' gensec backend!\n",
+			gensec_fake_gssapi_krb5_security_ops.name));
+		return ret;
+	}
+
+	return ret;
+}
diff --git a/source4/auth/gensec/gensec_krb5.h b/source4/auth/gensec/gensec_krb5.h
new file mode 100644
index 0000000..ee684be
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5.h
@@ -0,0 +1,10 @@
+/* See gensec_krb5_util.c for the license */
+
+krb5_error_code smb_krb5_rd_req_decoded(krb5_context context,
+					krb5_auth_context *auth_context,
+					const krb5_data *inbuf,
+					krb5_keytab keytab,
+					krb5_principal acceptor_principal,
+					krb5_data *outbuf,
+					krb5_ticket **ticket,
+					krb5_keyblock **keyblock);
diff --git a/source4/auth/gensec/gensec_krb5_heimdal.c b/source4/auth/gensec/gensec_krb5_heimdal.c
new file mode 100644
index 0000000..bc0d970
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5_heimdal.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 1997 - 2006 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* This file for code taken from the Heimdal code, to preserve licence */
+/* Modified by Andrew Bartlett <abartlet@samba.org> */
+
+#include "includes.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+#include "gensec_krb5.h"
+
+/* Taken from  accept_sec_context.c,v 1.65 */
+krb5_error_code smb_krb5_rd_req_decoded(krb5_context context,
+					krb5_auth_context *auth_context,
+					const krb5_data *inbuf,
+					krb5_keytab keytab,
+					krb5_principal acceptor_principal,
+					krb5_data *outbuf,
+					krb5_ticket **ticket,
+					krb5_keyblock **keyblock)
+{
+	krb5_rd_req_in_ctx in = NULL;
+	krb5_rd_req_out_ctx out = NULL;
+	krb5_error_code kret;
+
+	*keyblock = NULL;
+	*ticket = NULL;
+	outbuf->length = 0;
+	outbuf->data = NULL;
+
+	kret = krb5_rd_req_in_ctx_alloc(context, &in);
+	if (kret == 0)
+	    kret = krb5_rd_req_in_set_keytab(context, in, keytab);
+	if (kret) {
+	    if (in)
+		krb5_rd_req_in_ctx_free(context, in);
+	    return kret;
+	}
+
+	kret = krb5_rd_req_ctx(context,
+			       auth_context,
+			       inbuf,
+			       acceptor_principal,
+			       in, &out);
+	krb5_rd_req_in_ctx_free(context, in);
+	if (kret) {
+	    return kret;
+	}
+
+	/*
+	 * We need to remember some data on the context_handle.
+	 */
+	kret = krb5_rd_req_out_get_ticket(context, out,
+					  ticket);
+	if (kret == 0) {
+	    kret = krb5_rd_req_out_get_keyblock(context, out,
+						keyblock);
+	}
+	krb5_rd_req_out_ctx_free(context, out);
+
+	if (kret == 0) {
+		kret = krb5_mk_rep(context, *auth_context, outbuf);
+	}
+
+	if (kret) {
+		krb5_free_ticket(context, *ticket);
+		krb5_free_keyblock(context, *keyblock);
+		krb5_data_free(outbuf);
+	}
+
+	return kret;
+}
diff --git a/source4/auth/gensec/gensec_krb5_helpers.c b/source4/auth/gensec/gensec_krb5_helpers.c
new file mode 100644
index 0000000..21f2f1e
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5_helpers.c
@@ -0,0 +1,72 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Kerberos backend for GENSEC
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
+   Copyright (C) Andrew Tridgell 2001
+   Copyright (C) Luke Howard 2002-2003
+   Copyright (C) Stefan Metzmacher 2004-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "auth/auth.h"
+#include "auth/gensec/gensec.h"
+#include "auth/gensec/gensec_internal.h"
+#include "gensec_krb5_internal.h"
+#include "gensec_krb5_helpers.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+
+static struct gensec_krb5_state *get_private_state(const struct gensec_security *gensec_security)
+{
+	struct gensec_krb5_state *gensec_krb5_state = NULL;
+
+	if (strcmp(gensec_security->ops->name, "krb5") != 0) {
+		/* We require that the krb5 mechanism is being used. */
+		return NULL;
+	}
+
+	gensec_krb5_state = talloc_get_type(gensec_security->private_data,
+					    struct gensec_krb5_state);
+	return gensec_krb5_state;
+}
+
+/*
+ * Returns 1 if our ticket has the initial flag set, 0 if not, and -1 in case of
+ * error.
+ */
+int gensec_krb5_initial_ticket(const struct gensec_security *gensec_security)
+{
+	struct gensec_krb5_state *gensec_krb5_state = NULL;
+
+	gensec_krb5_state = get_private_state(gensec_security);
+	if (gensec_krb5_state == NULL) {
+		return -1;
+	}
+
+	if (gensec_krb5_state->ticket == NULL) {
+		/* We don't have a ticket */
+		return -1;
+	}
+
+#ifdef SAMBA4_USES_HEIMDAL
+	return gensec_krb5_state->ticket->ticket.flags.initial;
+#else /* MIT KERBEROS */
+	return (gensec_krb5_state->ticket->enc_part2->flags & TKT_FLG_INITIAL) ? 1 : 0;
+#endif /* SAMBA4_USES_HEIMDAL */
+}
diff --git a/source4/auth/gensec/gensec_krb5_helpers.h b/source4/auth/gensec/gensec_krb5_helpers.h
new file mode 100644
index 0000000..d7b694d
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5_helpers.h
@@ -0,0 +1,32 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Kerberos backend for GENSEC
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
+   Copyright (C) Andrew Tridgell 2001
+   Copyright (C) Luke Howard 2002-2003
+   Copyright (C) Stefan Metzmacher 2004-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+struct gensec_security;
+
+/*
+ * Returns 1 if our ticket has the initial flag set, 0 if not, and -1 in case of
+ * error.
+ */
+int gensec_krb5_initial_ticket(const struct gensec_security *gensec_security);
diff --git a/source4/auth/gensec/gensec_krb5_internal.h b/source4/auth/gensec/gensec_krb5_internal.h
new file mode 100644
index 0000000..0bb796f
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5_internal.h
@@ -0,0 +1,47 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Kerberos backend for GENSEC
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
+   Copyright (C) Andrew Tridgell 2001
+   Copyright (C) Luke Howard 2002-2003
+   Copyright (C) Stefan Metzmacher 2004-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "auth/gensec/gensec.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+
+enum GENSEC_KRB5_STATE {
+	GENSEC_KRB5_SERVER_START,
+	GENSEC_KRB5_CLIENT_START,
+	GENSEC_KRB5_CLIENT_MUTUAL_AUTH,
+	GENSEC_KRB5_DONE
+};
+
+struct gensec_krb5_state {
+	enum GENSEC_KRB5_STATE state_position;
+	struct smb_krb5_context *smb_krb5_context;
+	krb5_auth_context auth_context;
+	krb5_data enc_ticket;
+	krb5_keyblock *keyblock;
+	krb5_ticket *ticket;
+	bool gssapi;
+	krb5_flags ap_req_options;
+};
diff --git a/source4/auth/gensec/gensec_krb5_mit.c b/source4/auth/gensec/gensec_krb5_mit.c
new file mode 100644
index 0000000..f7b3129
--- /dev/null
+++ b/source4/auth/gensec/gensec_krb5_mit.c
@@ -0,0 +1,102 @@
+
+#include "includes.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+#include "gensec_krb5.h"
+
+static krb5_error_code smb_krb5_get_longterm_key(krb5_context context,
+						 krb5_const_principal server,
+						 krb5_kvno kvno,
+						 krb5_enctype etype,
+						 krb5_keytab keytab,
+						 krb5_keyblock **keyblock_out)
+{
+	krb5_error_code code = EINVAL;
+
+	krb5_keytab_entry kt_entry;
+
+	code = krb5_kt_get_entry(context,
+				 keytab,
+				 server,
+				 kvno,
+				 etype,
+				 &kt_entry);
+	if (code != 0) {
+		return code;
+	}
+
+	code = krb5_copy_keyblock(context,
+				  &kt_entry.key,
+				  keyblock_out);
+	krb5_free_keytab_entry_contents(context, &kt_entry);
+
+	return code;
+}
+
+krb5_error_code smb_krb5_rd_req_decoded(krb5_context context,
+					krb5_auth_context *auth_context,
+					const krb5_data *request,
+					krb5_keytab keytab,
+					krb5_principal acceptor_principal,
+					krb5_data *reply,
+					krb5_ticket **pticket,
+					krb5_keyblock **pkeyblock)
+{
+	krb5_error_code code;
+	krb5_flags ap_req_options = 0;
+	krb5_ticket *ticket = NULL;
+	krb5_keyblock *keyblock = NULL;
+
+	*pticket = NULL;
+	*pkeyblock = NULL;
+	reply->length = 0;
+	reply->data = NULL;
+
+	code = krb5_rd_req(context,
+			   auth_context,
+			   request,
+			   acceptor_principal,
+			   keytab,
+			   &ap_req_options,
+			   &ticket);
+	if (code != 0) {
+		DBG_ERR("krb5_rd_req failed: %s\n",
+			error_message(code));
+		return code;
+	}
+
+	/*
+	 * Get the long term key from the keytab to be able to verify the PAC
+	 * signature.
+	 *
+	 * FIXME: Use ticket->enc_part.kvno ???
+	 * Getting the latest kvno with passing 0 fixes:
+	 * make -j test TESTS="samba4.winbind.pac.ad_member"
+	 */
+	code = smb_krb5_get_longterm_key(context,
+					 ticket->server,
+					 0, /* kvno */
+					 ticket->enc_part.enctype,
+					 keytab,
+					 &keyblock);
+	if (code != 0) {
+		DBG_ERR("smb_krb5_get_longterm_key failed: %s\n",
+			error_message(code));
+		krb5_free_ticket(context, ticket);
+
+		return code;
+	}
+
+	code = krb5_mk_rep(context, *auth_context, reply);
+	if (code != 0) {
+		DBG_ERR("krb5_mk_rep failed: %s\n",
+			error_message(code));
+		krb5_free_ticket(context, ticket);
+		krb5_free_keyblock(context, keyblock);
+	}
+
+	*pticket = ticket;
+	*pkeyblock = keyblock;
+
+	return code;
+}
diff --git a/source4/auth/gensec/gensec_tstream.c b/source4/auth/gensec/gensec_tstream.c
new file mode 100644
index 0000000..cc7c83c
--- /dev/null
+++ b/source4/auth/gensec/gensec_tstream.c
@@ -0,0 +1,616 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   tstream based generic authentication interface
+
+   Copyright (c) 2010 Stefan Metzmacher
+   Copyright (c) 2010 Andreas Schneider <asn@redhat.com>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "system/network.h"
+#include "auth/gensec/gensec.h"
+#include "auth/gensec/gensec_proto.h"
+#include "auth/gensec/gensec_tstream.h"
+#include "lib/tsocket/tsocket.h"
+#include "lib/tsocket/tsocket_internal.h"
+#include "auth/gensec/gensec_toplevel_proto.h"
+
+static const struct tstream_context_ops tstream_gensec_ops;
+
+struct tstream_gensec {
+	struct tstream_context *plain_stream;
+
+	struct gensec_security *gensec_security;
+
+	int error;
+
+	struct {
+		size_t max_unwrapped_size;
+		size_t max_wrapped_size;
+	} write;
+
+	struct {
+		off_t ofs;
+		size_t left;
+		DATA_BLOB unwrapped;
+	} read;
+};
+
+_PUBLIC_ NTSTATUS _gensec_create_tstream(TALLOC_CTX *mem_ctx,
+					 struct gensec_security *gensec_security,
+					 struct tstream_context *plain_stream,
+					 struct tstream_context **_gensec_stream,
+					 const char *location)
+{
+	struct tstream_context *gensec_stream;
+	struct tstream_gensec *tgss;
+
+	gensec_stream = tstream_context_create(mem_ctx,
+					       &tstream_gensec_ops,
+					       &tgss,
+					       struct tstream_gensec,
+					       location);
+	if (gensec_stream == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	tgss->plain_stream = plain_stream;
+	tgss->gensec_security = gensec_security;
+	tgss->error = 0;
+
+	if (!gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN) &&
+	    !gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
+		talloc_free(gensec_stream);
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	tgss->write.max_unwrapped_size = gensec_max_input_size(gensec_security);
+	tgss->write.max_wrapped_size = gensec_max_wrapped_size(gensec_security);
+
+	ZERO_STRUCT(tgss->read);
+
+	*_gensec_stream = gensec_stream;
+	return NT_STATUS_OK;
+}
+
+static ssize_t tstream_gensec_pending_bytes(struct tstream_context *stream)
+{
+	struct tstream_gensec *tgss =
+		tstream_context_data(stream,
+		struct tstream_gensec);
+
+	if (tgss->error != 0) {
+		errno = tgss->error;
+		return -1;
+	}
+
+	return tgss->read.left;
+}
+
+struct tstream_gensec_readv_state {
+	struct tevent_context *ev;
+	struct tstream_context *stream;
+
+	struct iovec *vector;
+	int count;
+
+	struct {
+		bool asked_for_hdr;
+		uint8_t hdr[4];
+		bool asked_for_blob;
+		DATA_BLOB blob;
+	} wrapped;
+
+	int ret;
+};
+
+static void tstream_gensec_readv_wrapped_next(struct tevent_req *req);
+
+static struct tevent_req *tstream_gensec_readv_send(TALLOC_CTX *mem_ctx,
+						    struct tevent_context *ev,
+						    struct tstream_context *stream,
+						    struct iovec *vector,
+						    size_t count)
+{
+	struct tstream_gensec *tgss =
+		tstream_context_data(stream,
+		struct tstream_gensec);
+	struct tevent_req *req;
+	struct tstream_gensec_readv_state *state;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct tstream_gensec_readv_state);
+	if (!req) {
+		return NULL;
+	}
+
+	if (tgss->error != 0) {
+		tevent_req_error(req, tgss->error);
+		return tevent_req_post(req, ev);
+	}
+
+	state->ev = ev;
+	state->stream = stream;
+	state->ret = 0;
+
+	/*
+	 * we make a copy of the vector so we can change the structure
+	 */
+	state->vector = talloc_array(state, struct iovec, count);
+	if (tevent_req_nomem(state->vector, req)) {
+		return tevent_req_post(req, ev);
+	}
+	memcpy(state->vector, vector, sizeof(struct iovec) * count);
+	state->count = count;
+
+	tstream_gensec_readv_wrapped_next(req);
+	if (!tevent_req_is_in_progress(req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	return req;
+}
+
+static int tstream_gensec_readv_next_vector(struct tstream_context *unix_stream,
+					    void *private_data,
+					    TALLOC_CTX *mem_ctx,
+					    struct iovec **_vector,
+					    size_t *_count);
+static void tstream_gensec_readv_wrapped_done(struct tevent_req *subreq);
+
+static void tstream_gensec_readv_wrapped_next(struct tevent_req *req)
+{
+	struct tstream_gensec_readv_state *state =
+		tevent_req_data(req,
+		struct tstream_gensec_readv_state);
+	struct tstream_gensec *tgss =
+		tstream_context_data(state->stream,
+		struct tstream_gensec);
+	struct tevent_req *subreq;
+
+	/*
+	 * copy the pending buffer first
+	 */
+	while (tgss->read.left > 0 && state->count > 0) {
+		uint8_t *base = (uint8_t *)state->vector[0].iov_base;
+		size_t len = MIN(tgss->read.left, state->vector[0].iov_len);
+
+		memcpy(base, tgss->read.unwrapped.data + tgss->read.ofs, len);
+
+		base += len;
+		state->vector[0].iov_base = (char *) base;
+		state->vector[0].iov_len -= len;
+
+		tgss->read.ofs += len;
+		tgss->read.left -= len;
+
+		if (state->vector[0].iov_len == 0) {
+			state->vector += 1;
+			state->count -= 1;
+		}
+
+		state->ret += len;
+	}
+
+	if (state->count == 0) {
+		tevent_req_done(req);
+		return;
+	}
+
+	data_blob_free(&tgss->read.unwrapped);
+	ZERO_STRUCT(state->wrapped);
+
+	subreq = tstream_readv_pdu_send(state, state->ev,
+					tgss->plain_stream,
+					tstream_gensec_readv_next_vector,
+					state);
+	if (tevent_req_nomem(subreq, req)) {
+		return;
+	}
+	tevent_req_set_callback(subreq, tstream_gensec_readv_wrapped_done, req);
+}
+
+static int tstream_gensec_readv_next_vector(struct tstream_context *unix_stream,
+					    void *private_data,
+					    TALLOC_CTX *mem_ctx,
+					    struct iovec **_vector,
+					    size_t *_count)
+{
+	struct tstream_gensec_readv_state *state =
+		talloc_get_type_abort(private_data,
+		struct tstream_gensec_readv_state);
+	struct iovec *vector;
+	size_t count = 1;
+
+	/* we need to get a message header */
+	vector = talloc_array(mem_ctx, struct iovec, count);
+	if (!vector) {
+		return -1;
+	}
+
+	if (!state->wrapped.asked_for_hdr) {
+		state->wrapped.asked_for_hdr = true;
+		vector[0].iov_base = (char *)state->wrapped.hdr;
+		vector[0].iov_len = sizeof(state->wrapped.hdr);
+	} else if (!state->wrapped.asked_for_blob) {
+		uint32_t msg_len;
+
+		state->wrapped.asked_for_blob = true;
+
+		msg_len = RIVAL(state->wrapped.hdr, 0);
+
+		/*
+		 * I got a Windows 2012R2 server responding with
+		 * a message of 0x1b28a33.
+		 */
+		if (msg_len > 0x0FFFFFFF) {
+			errno = EMSGSIZE;
+			return -1;
+		}
+
+		if (msg_len == 0) {
+			errno = EMSGSIZE;
+			return -1;
+		}
+
+		state->wrapped.blob = data_blob_talloc(state, NULL, msg_len);
+		if (state->wrapped.blob.data == NULL) {
+			return -1;
+		}
+
+		vector[0].iov_base = (char *)state->wrapped.blob.data;
+		vector[0].iov_len = state->wrapped.blob.length;
+	} else {
+		*_vector = NULL;
+		*_count = 0;
+		return 0;
+	}
+
+	*_vector = vector;
+	*_count = count;
+	return 0;
+}
+
+static void tstream_gensec_readv_wrapped_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req =
+		tevent_req_callback_data(subreq,
+		struct tevent_req);
+	struct tstream_gensec_readv_state *state =
+		tevent_req_data(req,
+		struct tstream_gensec_readv_state);
+	struct tstream_gensec *tgss =
+		tstream_context_data(state->stream,
+		struct tstream_gensec);
+	int ret;
+	int sys_errno;
+	NTSTATUS status;
+
+	ret = tstream_readv_pdu_recv(subreq, &sys_errno);
+	TALLOC_FREE(subreq);
+	if (ret == -1) {
+		tgss->error = sys_errno;
+		tevent_req_error(req, sys_errno);
+		return;
+	}
+
+	status = gensec_unwrap(tgss->gensec_security,
+			       state,
+			       &state->wrapped.blob,
+			       &tgss->read.unwrapped);
+	if (!NT_STATUS_IS_OK(status)) {
+		tgss->error = EIO;
+		tevent_req_error(req, tgss->error);
+		return;
+	}
+
+	data_blob_free(&state->wrapped.blob);
+
+	talloc_steal(tgss, tgss->read.unwrapped.data);
+	tgss->read.left = tgss->read.unwrapped.length;
+	tgss->read.ofs = 0;
+
+	tstream_gensec_readv_wrapped_next(req);
+}
+
+static int tstream_gensec_readv_recv(struct tevent_req *req, int *perrno)
+{
+	struct tstream_gensec_readv_state *state =
+		tevent_req_data(req,
+		struct tstream_gensec_readv_state);
+	int ret;
+
+	ret = tsocket_simple_int_recv(req, perrno);
+	if (ret == 0) {
+		ret = state->ret;
+	}
+
+	tevent_req_received(req);
+	return ret;
+}
+
+struct tstream_gensec_writev_state {
+	struct tevent_context *ev;
+	struct tstream_context *stream;
+
+	struct iovec *vector;
+	int count;
+
+	struct {
+		off_t ofs;
+		size_t left;
+		DATA_BLOB blob;
+	} unwrapped;
+
+	struct {
+		uint8_t hdr[4];
+		DATA_BLOB blob;
+		struct iovec iov[2];
+	} wrapped;
+
+	int ret;
+};
+
+static void tstream_gensec_writev_wrapped_next(struct tevent_req *req);
+
+static struct tevent_req *tstream_gensec_writev_send(TALLOC_CTX *mem_ctx,
+					struct tevent_context *ev,
+					struct tstream_context *stream,
+					const struct iovec *vector,
+					size_t count)
+{
+	struct tstream_gensec *tgss =
+		tstream_context_data(stream,
+		struct tstream_gensec);
+	struct tevent_req *req;
+	struct tstream_gensec_writev_state *state;
+	size_t i;
+	int total;
+	int chunk;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct tstream_gensec_writev_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	if (tgss->error != 0) {
+		tevent_req_error(req, tgss->error);
+		return tevent_req_post(req, ev);
+	}
+
+	state->ev = ev;
+	state->stream = stream;
+	state->ret = 0;
+
+	/*
+	 * we make a copy of the vector so we can change the structure
+	 */
+	state->vector = talloc_array(state, struct iovec, count);
+	if (tevent_req_nomem(state->vector, req)) {
+		return tevent_req_post(req, ev);
+	}
+	memcpy(state->vector, vector, sizeof(struct iovec) * count);
+	state->count = count;
+
+	total = 0;
+	for (i = 0; i < count; i++) {
+		/*
+		 * the generic tstream code makes sure that
+		 * this never wraps.
+		 */
+		total += vector[i].iov_len;
+	}
+
+	/*
+	 * We may need to send data in chunks.
+	 */
+	chunk = MIN(total, tgss->write.max_unwrapped_size);
+
+	state->unwrapped.blob = data_blob_talloc(state, NULL, chunk);
+	if (tevent_req_nomem(state->unwrapped.blob.data, req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	tstream_gensec_writev_wrapped_next(req);
+	if (!tevent_req_is_in_progress(req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	return req;
+}
+
+static void tstream_gensec_writev_wrapped_done(struct tevent_req *subreq);
+
+static void tstream_gensec_writev_wrapped_next(struct tevent_req *req)
+{
+	struct tstream_gensec_writev_state *state =
+		tevent_req_data(req,
+		struct tstream_gensec_writev_state);
+	struct tstream_gensec *tgss =
+		tstream_context_data(state->stream,
+		struct tstream_gensec);
+	struct tevent_req *subreq;
+	NTSTATUS status;
+
+	data_blob_free(&state->wrapped.blob);
+
+	state->unwrapped.left = state->unwrapped.blob.length;
+	state->unwrapped.ofs = 0;
+
+	/*
+	 * first fill our buffer
+	 */
+	while (state->unwrapped.left > 0 && state->count > 0) {
+		uint8_t *base = (uint8_t *)state->vector[0].iov_base;
+		size_t len = MIN(state->unwrapped.left, state->vector[0].iov_len);
+
+		memcpy(state->unwrapped.blob.data + state->unwrapped.ofs, base, len);
+
+		base += len;
+		state->vector[0].iov_base = (char *) base;
+		state->vector[0].iov_len -= len;
+
+		state->unwrapped.ofs += len;
+		state->unwrapped.left -= len;
+
+		if (state->vector[0].iov_len == 0) {
+			state->vector += 1;
+			state->count -= 1;
+		}
+
+		state->ret += len;
+	}
+
+	if (state->unwrapped.ofs == 0) {
+		tevent_req_done(req);
+		return;
+	}
+
+	state->unwrapped.blob.length = state->unwrapped.ofs;
+
+	status = gensec_wrap(tgss->gensec_security,
+			     state,
+			     &state->unwrapped.blob,
+			     &state->wrapped.blob);
+	if (!NT_STATUS_IS_OK(status)) {
+		tgss->error = EIO;
+		tevent_req_error(req, tgss->error);
+		return;
+	}
+
+	RSIVAL(state->wrapped.hdr, 0, state->wrapped.blob.length);
+
+	state->wrapped.iov[0].iov_base = (void *)state->wrapped.hdr;
+	state->wrapped.iov[0].iov_len = sizeof(state->wrapped.hdr);
+	state->wrapped.iov[1].iov_base = (void *)state->wrapped.blob.data;
+	state->wrapped.iov[1].iov_len = state->wrapped.blob.length;
+
+	subreq = tstream_writev_send(state, state->ev,
+				      tgss->plain_stream,
+				      state->wrapped.iov, 2);
+	if (tevent_req_nomem(subreq, req)) {
+		return;
+	}
+	tevent_req_set_callback(subreq,
+				tstream_gensec_writev_wrapped_done,
+				req);
+}
+
+static void tstream_gensec_writev_wrapped_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req =
+		tevent_req_callback_data(subreq,
+		struct tevent_req);
+	struct tstream_gensec_writev_state *state =
+		tevent_req_data(req,
+		struct tstream_gensec_writev_state);
+	struct tstream_gensec *tgss =
+		tstream_context_data(state->stream,
+		struct tstream_gensec);
+	int sys_errno;
+	int ret;
+
+	ret = tstream_writev_recv(subreq, &sys_errno);
+	TALLOC_FREE(subreq);
+	if (ret == -1) {
+		tgss->error = sys_errno;
+		tevent_req_error(req, sys_errno);
+		return;
+	}
+
+	tstream_gensec_writev_wrapped_next(req);
+}
+
+static int tstream_gensec_writev_recv(struct tevent_req *req,
+				   int *perrno)
+{
+	struct tstream_gensec_writev_state *state =
+		tevent_req_data(req,
+		struct tstream_gensec_writev_state);
+	int ret;
+
+	ret = tsocket_simple_int_recv(req, perrno);
+	if (ret == 0) {
+		ret = state->ret;
+	}
+
+	tevent_req_received(req);
+	return ret;
+}
+
+struct tstream_gensec_disconnect_state {
+	uint8_t _dummy;
+};
+
+static struct tevent_req *tstream_gensec_disconnect_send(TALLOC_CTX *mem_ctx,
+							 struct tevent_context *ev,
+							 struct tstream_context *stream)
+{
+	struct tstream_gensec *tgss =
+		tstream_context_data(stream,
+		struct tstream_gensec);
+	struct tevent_req *req;
+	struct tstream_gensec_disconnect_state *state;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct tstream_gensec_disconnect_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	if (tgss->error != 0) {
+		tevent_req_error(req, tgss->error);
+		return tevent_req_post(req, ev);
+	}
+
+	/*
+	 * The caller is responsible to do the real disconnect
+	 * on the plain stream!
+	 */
+	tgss->plain_stream = NULL;
+	tgss->error = ENOTCONN;
+
+	tevent_req_done(req);
+	return tevent_req_post(req, ev);
+}
+
+static int tstream_gensec_disconnect_recv(struct tevent_req *req,
+				       int *perrno)
+{
+	int ret;
+
+	ret = tsocket_simple_int_recv(req, perrno);
+
+	tevent_req_received(req);
+	return ret;
+}
+
+static const struct tstream_context_ops tstream_gensec_ops = {
+	.name                   = "gensec",
+
+	.pending_bytes          = tstream_gensec_pending_bytes,
+
+	.readv_send             = tstream_gensec_readv_send,
+	.readv_recv             = tstream_gensec_readv_recv,
+
+	.writev_send            = tstream_gensec_writev_send,
+	.writev_recv            = tstream_gensec_writev_recv,
+
+	.disconnect_send        = tstream_gensec_disconnect_send,
+	.disconnect_recv        = tstream_gensec_disconnect_recv,
+};
diff --git a/source4/auth/gensec/gensec_tstream.h b/source4/auth/gensec/gensec_tstream.h
new file mode 100644
index 0000000..18389d4
--- /dev/null
+++ b/source4/auth/gensec/gensec_tstream.h
@@ -0,0 +1,40 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   tstream based generic authentication interface
+
+   Copyright (c) 2010 Stefan Metzmacher
+   Copyright (c) 2010 Andreas Schneider <asn@redhat.com>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _GENSEC_TSTREAM_H_
+#define _GENSEC_TSTREAM_H_
+
+struct gensec_context;
+struct tstream_context;
+
+NTSTATUS _gensec_create_tstream(TALLOC_CTX *mem_ctx,
+				struct gensec_security *gensec_security,
+				struct tstream_context *plain_tstream,
+				struct tstream_context **gensec_tstream,
+				const char *location);
+#define gensec_create_tstream(mem_ctx, gensec_security, \
+			      plain_tstream, gensec_tstream) \
+	_gensec_create_tstream(mem_ctx, gensec_security, \
+			       plain_tstream, gensec_tstream, \
+			       __location__)
+
+#endif /* _GENSEC_TSTREAM_H_ */
diff --git a/source4/auth/gensec/pygensec.c b/source4/auth/gensec/pygensec.c
new file mode 100644
index 0000000..97ced8f
--- /dev/null
+++ b/source4/auth/gensec/pygensec.c
@@ -0,0 +1,779 @@
+/* 
+   Unix SMB/CIFS implementation.
+   Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2009
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "lib/replace/system/python.h"
+#include "python/py3compat.h"
+#include "includes.h"
+#include "python/modules.h"
+#include "param/pyparam.h"
+#include "auth/gensec/gensec.h"
+#include "auth/gensec/gensec_internal.h" /* TODO: remove this */
+#include "auth/credentials/pycredentials.h"
+#include "libcli/util/pyerrors.h"
+#include "python/modules.h"
+#include <pytalloc.h>
+#include <tevent.h>
+#include "librpc/rpc/pyrpc_util.h"
+
+static PyObject *py_get_name_by_authtype(PyObject *self, PyObject *args)
+{
+	int type;
+	const char *name;
+	struct gensec_security *security;
+
+	if (!PyArg_ParseTuple(args, "i", &type))
+		return NULL;
+
+	security = pytalloc_get_type(self, struct gensec_security);
+
+	name = gensec_get_name_by_authtype(security, type);
+	if (name == NULL)
+		Py_RETURN_NONE;
+
+	return PyUnicode_FromString(name);
+}
+
+static struct gensec_settings *settings_from_object(TALLOC_CTX *mem_ctx, PyObject *object)
+{
+	struct gensec_settings *s;
+	PyObject *py_hostname, *py_lp_ctx;
+
+	if (!PyDict_Check(object)) {
+		PyErr_SetString(PyExc_ValueError, "settings should be a dictionary");
+		return NULL;
+	}
+
+	s = talloc_zero(mem_ctx, struct gensec_settings);
+	if (!s) return NULL;
+
+	py_hostname = PyDict_GetItemString(object, "target_hostname");
+	if (!py_hostname) {
+		PyErr_SetString(PyExc_ValueError, "settings.target_hostname not found");
+		return NULL;
+	}
+
+	py_lp_ctx = PyDict_GetItemString(object, "lp_ctx");
+	if (!py_lp_ctx) {
+		PyErr_SetString(PyExc_ValueError, "settings.lp_ctx not found");
+		return NULL;
+	}
+
+	s->target_hostname = PyUnicode_AsUTF8(py_hostname);
+	s->lp_ctx = lpcfg_from_py_object(s, py_lp_ctx);
+	return s;
+}
+
+static PyObject *py_gensec_start_client(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+	NTSTATUS status;
+	PyObject *self;
+	struct gensec_settings *settings;
+	const char *kwnames[] = { "settings", NULL };
+	PyObject *py_settings = Py_None;
+	struct gensec_security *gensec;
+	TALLOC_CTX *frame;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|O", discard_const_p(char *, kwnames), &py_settings))
+		return NULL;
+
+	frame = talloc_stackframe();
+
+	if (py_settings != Py_None) {
+		settings = settings_from_object(frame, py_settings);
+		if (settings == NULL) {
+			PyErr_NoMemory();
+			TALLOC_FREE(frame);
+			return NULL;
+		}
+	} else {
+		settings = talloc_zero(frame, struct gensec_settings);
+		if (settings == NULL) {
+			PyErr_NoMemory();
+			TALLOC_FREE(frame);
+			return NULL;
+		}
+
+		settings->lp_ctx = loadparm_init_global(true);
+		if (settings->lp_ctx == NULL) {
+			PyErr_NoMemory();
+			TALLOC_FREE(frame);
+			return NULL;
+		}
+	}
+
+	status = gensec_init();
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		TALLOC_FREE(frame);
+		return NULL;
+	}
+
+	status = gensec_client_start(frame, &gensec, settings);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		TALLOC_FREE(frame);
+		return NULL;
+	}
+
+	self = pytalloc_steal(type, gensec);
+	TALLOC_FREE(frame);
+
+	return (PyObject *)self;
+}
+
+static PyObject *py_gensec_start_server(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+	NTSTATUS status;
+	PyObject *self;
+	struct gensec_settings *settings = NULL;
+	const char *kwnames[] = { "settings", "auth_context", NULL };
+	PyObject *py_settings = Py_None;
+	PyObject *py_auth_context = Py_None;
+	struct gensec_security *gensec;
+	struct auth4_context *auth_context = NULL;
+	TALLOC_CTX *frame;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|OO", discard_const_p(char *, kwnames), &py_settings, &py_auth_context))
+		return NULL;
+
+	frame = talloc_stackframe();
+
+	if (py_settings != Py_None) {
+		settings = settings_from_object(frame, py_settings);
+		if (settings == NULL) {
+			PyErr_NoMemory();
+			TALLOC_FREE(frame);
+			return NULL;
+		}
+	} else {
+		settings = talloc_zero(frame, struct gensec_settings);
+		if (settings == NULL) {
+			PyErr_NoMemory();
+			TALLOC_FREE(frame);
+			return NULL;
+		}
+
+		settings->lp_ctx = loadparm_init_global(true);
+		if (settings->lp_ctx == NULL) {
+			PyErr_NoMemory();
+			TALLOC_FREE(frame);
+			return NULL;
+		}
+	}
+
+	if (py_auth_context != Py_None) {
+		bool ok = py_check_dcerpc_type(py_auth_context,
+					       "samba.auth",
+					       "AuthContext");
+		if (!ok) {
+			return NULL;
+		}
+
+		auth_context = pytalloc_get_type(py_auth_context,
+						 struct auth4_context);
+		if (!auth_context) {
+			PyErr_Format(PyExc_TypeError,
+				     "Expected auth.AuthContext for auth_context argument, got %s",
+				     pytalloc_get_name(py_auth_context));
+			return NULL;
+		}
+	}
+
+	status = gensec_init();
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		TALLOC_FREE(frame);
+		return NULL;
+	}
+
+	status = gensec_server_start(frame, settings, auth_context, &gensec);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		TALLOC_FREE(frame);
+		return NULL;
+	}
+
+	self = pytalloc_steal(type, gensec);
+	TALLOC_FREE(frame);
+
+	return self;
+}
+
+static PyObject *py_gensec_set_target_hostname(PyObject *self, PyObject *args)
+{
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	char *target_hostname;
+	NTSTATUS status;
+
+	if (!PyArg_ParseTuple(args, "s", &target_hostname))
+		return NULL;
+
+	status = gensec_set_target_hostname(security, target_hostname);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+	
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_set_target_service(PyObject *self, PyObject *args)
+{
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	char *target_service;
+	NTSTATUS status;
+
+	if (!PyArg_ParseTuple(args, "s", &target_service))
+		return NULL;
+
+	status = gensec_set_target_service(security, target_service);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+	
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_set_target_service_description(PyObject *self, PyObject *args)
+{
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	char *target_service_description;
+	NTSTATUS status;
+
+	if (!PyArg_ParseTuple(args, "s", &target_service_description))
+		return NULL;
+
+	status = gensec_set_target_service_description(security,
+						       target_service_description);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_set_credentials(PyObject *self, PyObject *args)
+{
+	PyObject *py_creds = Py_None;
+	struct cli_credentials *creds;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	NTSTATUS status;
+
+	if (!PyArg_ParseTuple(args, "O", &py_creds))
+		return NULL;
+
+	creds = PyCredentials_AsCliCredentials(py_creds);
+	if (!creds) {
+		PyErr_Format(
+			PyExc_TypeError,
+			"Expected samba.credentials for credentials argument, "
+			"got %s", pytalloc_get_name(py_creds));
+		return NULL;
+	}
+
+	status = gensec_set_credentials(security, creds);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_session_info(PyObject *self,
+		PyObject *Py_UNUSED(ignored))
+{
+	TALLOC_CTX *mem_ctx;
+	NTSTATUS status;
+	PyObject *py_session_info;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	struct auth_session_info *info;
+	if (security->ops == NULL) {
+		PyErr_SetString(PyExc_RuntimeError, "no mechanism selected");
+		return NULL;
+	}
+	mem_ctx = talloc_new(NULL);
+	if (mem_ctx == NULL) {
+		return PyErr_NoMemory();
+	}
+
+	status = gensec_session_info(security, mem_ctx, &info);
+	if (NT_STATUS_IS_ERR(status)) {
+		talloc_free(mem_ctx);
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	py_session_info = py_return_ndr_struct("samba.dcerpc.auth", "session_info",
+						 info, info);
+	talloc_free(mem_ctx);
+	return py_session_info;
+}
+
+static PyObject *py_gensec_session_key(PyObject *self,
+		PyObject *Py_UNUSED(ignored))
+{
+	TALLOC_CTX *mem_ctx;
+	NTSTATUS status;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	DATA_BLOB session_key = data_blob_null;
+	static PyObject *session_key_obj = NULL;
+
+	if (security->ops == NULL) {
+		PyErr_SetString(PyExc_RuntimeError, "no mechanism selected");
+		return NULL;
+	}
+	mem_ctx = talloc_new(NULL);
+	if (mem_ctx == NULL) {
+		return PyErr_NoMemory();
+	}
+
+	status = gensec_session_key(security, mem_ctx, &session_key);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(mem_ctx);
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	session_key_obj = PyBytes_FromStringAndSize((const char *)session_key.data,
+						     session_key.length);
+	talloc_free(mem_ctx);
+	return session_key_obj;
+}
+
+static PyObject *py_gensec_start_mech_by_name(PyObject *self, PyObject *args)
+{
+	char *name;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	NTSTATUS status;
+
+	if (!PyArg_ParseTuple(args, "s", &name))
+		return NULL;
+
+	status = gensec_start_mech_by_name(security, name);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_start_mech_by_sasl_name(PyObject *self, PyObject *args)
+{
+	char *sasl_name;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	NTSTATUS status;
+
+	if (!PyArg_ParseTuple(args, "s", &sasl_name))
+		return NULL;
+
+	status = gensec_start_mech_by_sasl_name(security, sasl_name);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_start_mech_by_authtype(PyObject *self, PyObject *args)
+{
+	int authtype, level;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	NTSTATUS status;
+	if (!PyArg_ParseTuple(args, "ii", &authtype, &level))
+		return NULL;
+
+	status = gensec_start_mech_by_authtype(security, authtype, level);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_want_feature(PyObject *self, PyObject *args)
+{
+	int feature;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	/* This is i (and declared as an int above) by design, as they are handled as an integer in python */
+	if (!PyArg_ParseTuple(args, "i", &feature))
+		return NULL;
+
+	gensec_want_feature(security, feature);
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_have_feature(PyObject *self, PyObject *args)
+{
+	int feature;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	/* This is i (and declared as an int above) by design, as they are handled as an integer in python */
+	if (!PyArg_ParseTuple(args, "i", &feature))
+		return NULL;
+
+	if (gensec_have_feature(security, feature)) {
+		Py_RETURN_TRUE;
+	} 
+	Py_RETURN_FALSE;
+}
+
+static PyObject *py_gensec_set_max_update_size(PyObject *self, PyObject *args)
+{
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	unsigned int max_update_size = 0;
+
+	if (!PyArg_ParseTuple(args, "I", &max_update_size))
+		return NULL;
+
+	gensec_set_max_update_size(security, max_update_size);
+
+	Py_RETURN_NONE;
+}
+
+static PyObject *py_gensec_max_update_size(PyObject *self,
+		PyObject *Py_UNUSED(ignored))
+{
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	unsigned int max_update_size = gensec_max_update_size(security);
+
+	return PyLong_FromLong(max_update_size);
+}
+
+static PyObject *py_gensec_update(PyObject *self, PyObject *args)
+{
+	NTSTATUS status;
+	TALLOC_CTX *mem_ctx;
+	DATA_BLOB in, out;
+	PyObject *py_bytes, *result, *py_in;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	PyObject *finished_processing;
+	char *data = NULL;
+	Py_ssize_t len;
+	int err;
+
+	if (!PyArg_ParseTuple(args, "O", &py_in))
+		return NULL;
+
+	mem_ctx = talloc_new(NULL);
+	if (mem_ctx == NULL) {
+		return PyErr_NoMemory();
+	}
+
+	err = PyBytes_AsStringAndSize(py_in, &data, &len);
+	if (err) {
+		talloc_free(mem_ctx);
+		return NULL;
+	}
+
+	/*
+	 * Make a copy of the input buffer, as gensec_update may modify its
+	 * input argument.
+	 */
+	in = data_blob_talloc(mem_ctx, data, len);
+	if (!in.data) {
+		talloc_free(mem_ctx);
+		return PyErr_NoMemory();
+	}
+
+	status = gensec_update(security, mem_ctx, in, &out);
+
+	if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)
+	    && !NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		talloc_free(mem_ctx);
+		return NULL;
+	}
+	py_bytes = PyBytes_FromStringAndSize((const char *)out.data,
+					     out.length);
+	talloc_free(mem_ctx);
+
+	if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		finished_processing = Py_False;
+	} else {
+		finished_processing = Py_True;
+	}
+
+	result = PyTuple_Pack(2, finished_processing, py_bytes);
+	Py_XDECREF(py_bytes);
+	return result;
+}
+
+static PyObject *py_gensec_wrap(PyObject *self, PyObject *args)
+{
+	NTSTATUS status;
+
+	TALLOC_CTX *mem_ctx;
+	DATA_BLOB in, out;
+	PyObject *ret, *py_in;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+
+	if (!PyArg_ParseTuple(args, "O", &py_in))
+		return NULL;
+
+	mem_ctx = talloc_new(NULL);
+	if (mem_ctx == NULL) {
+		return PyErr_NoMemory();
+	}
+
+	if (!PyBytes_Check(py_in)) {
+		talloc_free(mem_ctx);
+		PyErr_Format(PyExc_TypeError, "bytes expected");
+		return NULL;
+	}
+	in.data = (uint8_t *)PyBytes_AsString(py_in);
+	in.length = PyBytes_Size(py_in);
+
+	status = gensec_wrap(security, mem_ctx, &in, &out);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		talloc_free(mem_ctx);
+		return NULL;
+	}
+
+	ret = PyBytes_FromStringAndSize((const char *)out.data, out.length);
+	talloc_free(mem_ctx);
+	return ret;
+}
+
+
+static PyObject *py_gensec_unwrap(PyObject *self, PyObject *args)
+{
+	NTSTATUS status;
+
+	TALLOC_CTX *mem_ctx;
+	DATA_BLOB in, out;
+	PyObject *ret, *py_in;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	char *data = NULL;
+	Py_ssize_t len;
+	int err;
+
+	if (!PyArg_ParseTuple(args, "O", &py_in))
+		return NULL;
+
+	mem_ctx = talloc_new(NULL);
+	if (mem_ctx == NULL) {
+		return PyErr_NoMemory();
+	}
+
+	err = PyBytes_AsStringAndSize(py_in, &data, &len);
+	if (err) {
+		talloc_free(mem_ctx);
+		return NULL;
+	}
+
+	/*
+	 * Make a copy of the input buffer, as gensec_unwrap may modify its
+	 * input argument.
+	 */
+	in = data_blob_talloc(mem_ctx, data, len);
+	if (!in.data) {
+		talloc_free(mem_ctx);
+		return PyErr_NoMemory();
+	}
+
+	status = gensec_unwrap(security, mem_ctx, &in, &out);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		talloc_free(mem_ctx);
+		return NULL;
+	}
+
+	ret = PyBytes_FromStringAndSize((const char *)out.data, out.length);
+	talloc_free(mem_ctx);
+	return ret;
+}
+
+static PyObject *py_gensec_sig_size(PyObject *self, PyObject *args)
+{
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+	Py_ssize_t data_size = 0;
+	size_t sig_size = 0;
+
+	if (!PyArg_ParseTuple(args, "n", &data_size)) {
+		return NULL;
+	}
+
+	sig_size = gensec_sig_size(security, data_size);
+
+	return PyLong_FromSize_t(sig_size);
+}
+
+static PyObject *py_gensec_sign_packet(PyObject *self, PyObject *args)
+{
+	NTSTATUS status;
+	TALLOC_CTX *mem_ctx = NULL;
+	Py_ssize_t data_length = 0;
+	Py_ssize_t pdu_length = 0;
+	DATA_BLOB data, pdu, sig;
+	PyObject *py_sig;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+
+	if (!PyArg_ParseTuple(args, "z#z#", &data.data, &data_length, &pdu.data, &pdu_length)) {
+		return NULL;
+	}
+	data.length = data_length;
+	pdu.length = pdu_length;
+
+	mem_ctx = talloc_new(NULL);
+	if (mem_ctx == NULL) {
+		return PyErr_NoMemory();
+	}
+
+	status = gensec_sign_packet(security, mem_ctx,
+				    data.data, data.length,
+				    pdu.data, pdu.length, &sig);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		talloc_free(mem_ctx);
+		return NULL;
+	}
+
+	py_sig = PyBytes_FromStringAndSize((const char *)sig.data, sig.length);
+	talloc_free(mem_ctx);
+	return py_sig;
+}
+
+static PyObject *py_gensec_check_packet(PyObject *self, PyObject *args)
+{
+	NTSTATUS status;
+	Py_ssize_t data_length = 0;
+	Py_ssize_t pdu_length = 0;
+	Py_ssize_t sig_length = 0;
+	DATA_BLOB data, pdu, sig;
+	struct gensec_security *security = pytalloc_get_type(self, struct gensec_security);
+
+	if (!PyArg_ParseTuple(args, "z#z#z#",
+			      &data.data, &data_length,
+			      &pdu.data, &pdu_length,
+			      &sig.data, &sig_length)) {
+		return NULL;
+	}
+	data.length = data_length;
+	pdu.length = pdu_length;
+	sig.length = sig_length;
+
+	status = gensec_check_packet(security,
+				     data.data, data.length,
+				     pdu.data, pdu.length, &sig);
+	if (!NT_STATUS_IS_OK(status)) {
+		PyErr_SetNTSTATUS(status);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
+static PyMethodDef py_gensec_security_methods[] = {
+	{ "start_client", PY_DISCARD_FUNC_SIG(PyCFunction,
+					      py_gensec_start_client),
+		METH_VARARGS|METH_KEYWORDS|METH_CLASS,
+		"S.start_client(settings) -> gensec" },
+	{ "start_server", PY_DISCARD_FUNC_SIG(PyCFunction,
+					      py_gensec_start_server),
+		METH_VARARGS|METH_KEYWORDS|METH_CLASS,
+		"S.start_server(auth_ctx, settings) -> gensec" },
+	{ "set_credentials", (PyCFunction)py_gensec_set_credentials, METH_VARARGS, 
+		"S.set_credentials(credentials)" },
+	{ "set_target_hostname", (PyCFunction)py_gensec_set_target_hostname, METH_VARARGS, 
+		"S.set_target_hostname(target_hostname) \n This sets the Kerberos target hostname to obtain a ticket for." },
+	{ "set_target_service", (PyCFunction)py_gensec_set_target_service, METH_VARARGS, 
+		"S.set_target_service(target_service) \n This sets the Kerberos target service to obtain a ticket for.  The default value is 'host'" },
+	{ "set_target_service_description", (PyCFunction)py_gensec_set_target_service_description, METH_VARARGS,
+		"S.set_target_service_description(target_service_description) \n This description is set server-side and used in authentication and authorization logs.  The default value is that provided to set_target_service() or None."},
+	{ "session_info", (PyCFunction)py_gensec_session_info, METH_NOARGS,
+		"S.session_info() -> info" },
+	{ "session_key", (PyCFunction)py_gensec_session_key, METH_NOARGS,
+		"S.session_key() -> key" },
+	{ "start_mech_by_name", (PyCFunction)py_gensec_start_mech_by_name, METH_VARARGS,
+		"S.start_mech_by_name(name)" },
+	{ "start_mech_by_sasl_name", (PyCFunction)py_gensec_start_mech_by_sasl_name, METH_VARARGS,
+		"S.start_mech_by_sasl_name(name)" },
+	{ "start_mech_by_authtype", (PyCFunction)py_gensec_start_mech_by_authtype, METH_VARARGS,
+		"S.start_mech_by_authtype(authtype, level)" },
+	{ "get_name_by_authtype", (PyCFunction)py_get_name_by_authtype, METH_VARARGS,
+		"S.get_name_by_authtype(authtype) -> name\nLookup an auth type." },
+	{ "want_feature", (PyCFunction)py_gensec_want_feature, METH_VARARGS,
+		"S.want_feature(feature)\n Request that GENSEC negotiate a particular feature." },
+	{ "have_feature", (PyCFunction)py_gensec_have_feature, METH_VARARGS,
+		"S.have_feature()\n Return True if GENSEC negotiated a particular feature." },
+	{ "set_max_update_size",  (PyCFunction)py_gensec_set_max_update_size, METH_VARARGS,
+		"S.set_max_update_size(max_size) \n Some mechs can fragment update packets, needs to be use before the mech is started." },
+	{ "max_update_size",  (PyCFunction)py_gensec_max_update_size, METH_NOARGS,
+		"S.max_update_size() \n Return the current max_update_size." },
+	{ "update",  (PyCFunction)py_gensec_update, METH_VARARGS,
+		"S.update(blob_in) -> (finished, blob_out)\nPerform one step in a GENSEC dance.  Repeat with new packets until finished is true or exception." },
+	{ "wrap",  (PyCFunction)py_gensec_wrap, METH_VARARGS,
+		"S.wrap(blob_in) -> blob_out\nPackage one clear packet into a wrapped GENSEC packet." },
+	{ "unwrap",  (PyCFunction)py_gensec_unwrap, METH_VARARGS,
+		"S.unwrap(blob_in) -> blob_out\nPerform one wrapped GENSEC packet into a clear packet." },
+	{ "sig_size",  (PyCFunction)py_gensec_sig_size, METH_VARARGS,
+		"S.sig_size(data_size) -> sig_size\nSize of the DCERPC packet signature" },
+	{ "sign_packet",  (PyCFunction)py_gensec_sign_packet, METH_VARARGS,
+		"S.sign_packet(data, whole_pdu) -> sig\nSign a DCERPC packet." },
+	{ "check_packet",  (PyCFunction)py_gensec_check_packet, METH_VARARGS,
+		"S.check_packet(data, whole_pdu, sig)\nCheck a DCERPC packet." },
+	{0}
+};
+
+static struct PyModuleDef moduledef = {
+    PyModuleDef_HEAD_INIT,
+    .m_name = "gensec",
+    .m_doc = "Generic Security Interface.",
+    .m_size = -1,
+};
+
+static PyTypeObject Py_Security = {
+	.tp_name = "gensec.Security",
+	.tp_flags = Py_TPFLAGS_DEFAULT,
+	.tp_methods = py_gensec_security_methods,
+};
+
+MODULE_INIT_FUNC(gensec)
+{
+	PyObject *m;
+
+	if (pytalloc_BaseObject_PyType_Ready(&Py_Security) < 0)
+		return NULL;
+
+	m = PyModule_Create(&moduledef);
+	if (m == NULL)
+		return NULL;
+
+	PyModule_AddObject(m, "FEATURE_SESSION_KEY",     PyLong_FromLong(GENSEC_FEATURE_SESSION_KEY));
+	PyModule_AddObject(m, "FEATURE_SIGN",            PyLong_FromLong(GENSEC_FEATURE_SIGN));
+	PyModule_AddObject(m, "FEATURE_SEAL",            PyLong_FromLong(GENSEC_FEATURE_SEAL));
+	PyModule_AddObject(m, "FEATURE_DCE_STYLE",       PyLong_FromLong(GENSEC_FEATURE_DCE_STYLE));
+	PyModule_AddObject(m, "FEATURE_ASYNC_REPLIES",   PyLong_FromLong(GENSEC_FEATURE_ASYNC_REPLIES));
+	PyModule_AddObject(m, "FEATURE_DATAGRAM_MODE",   PyLong_FromLong(GENSEC_FEATURE_DATAGRAM_MODE));
+	PyModule_AddObject(m, "FEATURE_SIGN_PKT_HEADER", PyLong_FromLong(GENSEC_FEATURE_SIGN_PKT_HEADER));
+	PyModule_AddObject(m, "FEATURE_NEW_SPNEGO",      PyLong_FromLong(GENSEC_FEATURE_NEW_SPNEGO));
+
+	Py_INCREF(&Py_Security);
+	PyModule_AddObject(m, "Security", (PyObject *)&Py_Security);
+
+	return m;
+}
diff --git a/source4/auth/gensec/wscript_build b/source4/auth/gensec/wscript_build
new file mode 100644
index 0000000..2885eb0
--- /dev/null
+++ b/source4/auth/gensec/wscript_build
@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+
+bld.SAMBA_SUBSYSTEM('gensec_util',
+                    source='gensec_tstream.c',
+                    deps='tevent-util tevent samba-util LIBTSOCKET',
+                    autoproto='gensec_proto.h')
+
+gensec_krb5_sources = 'gensec_krb5_heimdal.c'
+if bld.CONFIG_SET('SAMBA_USES_MITKDC'):
+    gensec_krb5_sources = 'gensec_krb5_mit.c'
+
+bld.SAMBA_MODULE('gensec_krb5',
+	source='gensec_krb5.c ' + gensec_krb5_sources,
+	subsystem='gensec',
+	init_function='gensec_krb5_init',
+	deps='samba-credentials authkrb5 com_err',
+	internal_module=False,
+        enabled=bld.AD_DC_BUILD_IS_ENABLED()
+	)
+
+bld.SAMBA_SUBSYSTEM('gensec_krb5_helpers',
+    source='gensec_krb5_helpers.c',
+    deps='talloc authkrb5',
+    enabled=bld.AD_DC_BUILD_IS_ENABLED())
+
+bld.SAMBA_MODULE('gensec_gssapi',
+	source='gensec_gssapi.c',
+	subsystem='gensec',
+	init_function='gensec_gssapi_init',
+	deps='gssapi samba-credentials authkrb5 com_err'
+	)
+
+
+pytalloc_util = bld.pyembed_libname('pytalloc-util')
+pyparam_util = bld.pyembed_libname('pyparam_util')
+
+bld.SAMBA_PYTHON('pygensec',
+        source='pygensec.c',
+        deps='gensec %s %s' % (pytalloc_util, pyparam_util),
+        realname='samba/gensec.so'
+        )