s3-dcerpc: move crypto stuff in /librpc/crypto

Signed-off-by: Günther Deschner <gd@samba.org>

4 files changed, 1529 insertions, 0 deletions

diff --git a/source3/librpc/crypto/gse.c b/source3/librpc/crypto/gse.c
new file mode 100644
index 0000000000..c12656b0fa
--- /dev/null
+++ b/source3/librpc/crypto/gse.c
@@ -0,0 +1,1034 @@
+/*
+ *  GSSAPI Security Extensions
+ *  RPC Pipe client and server routines
+ *  Copyright (C) Simo Sorce 2010.
+ *
+ *  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/>.
+ */
+
+/* We support only GSSAPI/KRB5 here */
+
+#include "includes.h"
+#include "gse.h"
+
+#if defined(HAVE_KRB5) && defined(HAVE_GSSAPI_GSSAPI_EXT_H) && defined(HAVE_GSS_WRAP_IOV)
+
+#include "smb_krb5.h"
+#include "gse_krb5.h"
+
+#include <gssapi/gssapi.h>
+#include <gssapi/gssapi_krb5.h>
+#include <gssapi/gssapi_ext.h>
+
+#ifndef GSS_KRB5_INQ_SSPI_SESSION_KEY_OID
+#define GSS_KRB5_INQ_SSPI_SESSION_KEY_OID_LENGTH 11
+#define GSS_KRB5_INQ_SSPI_SESSION_KEY_OID "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x05\x05"
+#endif
+
+gss_OID_desc gse_sesskey_inq_oid = {
+	GSS_KRB5_INQ_SSPI_SESSION_KEY_OID_LENGTH,
+	(void *)GSS_KRB5_INQ_SSPI_SESSION_KEY_OID
+};
+
+#ifndef GSS_KRB5_SESSION_KEY_ENCTYPE_OID
+#define GSS_KRB5_SESSION_KEY_ENCTYPE_OID_LENGTH 10
+#define GSS_KRB5_SESSION_KEY_ENCTYPE_OID  "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04"
+#endif
+
+gss_OID_desc gse_sesskeytype_oid = {
+	GSS_KRB5_SESSION_KEY_ENCTYPE_OID_LENGTH,
+	(void *)GSS_KRB5_SESSION_KEY_ENCTYPE_OID
+};
+
+#define GSE_EXTRACT_RELEVANT_AUTHZ_DATA_OID_LENGTH 12
+/*					    EXTRACTION OID				   AUTHZ ID */
+#define GSE_EXTRACT_RELEVANT_AUTHZ_DATA_OID "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x05\x0a" "\x01"
+
+gss_OID_desc gse_authz_data_oid = {
+	GSE_EXTRACT_RELEVANT_AUTHZ_DATA_OID_LENGTH,
+	(void *)GSE_EXTRACT_RELEVANT_AUTHZ_DATA_OID
+};
+
+#ifndef GSS_KRB5_EXTRACT_AUTHTIME_FROM_SEC_CONTEXT_OID
+#define GSS_KRB5_EXTRACT_AUTHTIME_FROM_SEC_CONTEXT_OID_LENGTH 11
+#define GSS_KRB5_EXTRACT_AUTHTIME_FROM_SEC_CONTEXT_OID "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x05\x0c"
+#endif
+
+gss_OID_desc gse_authtime_oid = {
+	GSS_KRB5_EXTRACT_AUTHTIME_FROM_SEC_CONTEXT_OID_LENGTH,
+	(void *)GSS_KRB5_EXTRACT_AUTHTIME_FROM_SEC_CONTEXT_OID
+};
+
+static char *gse_errstr(TALLOC_CTX *mem_ctx, OM_uint32 maj, OM_uint32 min);
+
+struct gse_context {
+	krb5_context k5ctx;
+	krb5_ccache ccache;
+	krb5_keytab keytab;
+
+	gss_ctx_id_t gss_ctx;
+
+	gss_OID_desc gss_mech;
+	OM_uint32 gss_c_flags;
+	gss_cred_id_t creds;
+	gss_name_t server_name;
+
+	gss_OID ret_mech;
+	OM_uint32 ret_flags;
+	gss_cred_id_t delegated_creds;
+	gss_name_t client_name;
+
+	bool spnego_wrap;
+	bool more_processing;
+	bool authenticated;
+};
+
+/* free non talloc dependent contexts */
+static int gse_context_destructor(void *ptr)
+{
+	struct gse_context *gse_ctx;
+	OM_uint32 gss_min, gss_maj;
+
+	gse_ctx = talloc_get_type_abort(ptr, struct gse_context);
+	if (gse_ctx->k5ctx) {
+		if (gse_ctx->ccache) {
+			krb5_cc_close(gse_ctx->k5ctx, gse_ctx->ccache);
+			gse_ctx->ccache = NULL;
+		}
+		if (gse_ctx->keytab) {
+			krb5_kt_close(gse_ctx->k5ctx, gse_ctx->keytab);
+			gse_ctx->keytab = NULL;
+		}
+		krb5_free_context(gse_ctx->k5ctx);
+		gse_ctx->k5ctx = NULL;
+	}
+	if (gse_ctx->gss_ctx != GSS_C_NO_CONTEXT) {
+		gss_maj = gss_delete_sec_context(&gss_min,
+						 &gse_ctx->gss_ctx,
+						 GSS_C_NO_BUFFER);
+	}
+	if (gse_ctx->server_name) {
+		gss_maj = gss_release_name(&gss_min,
+					   &gse_ctx->server_name);
+	}
+	if (gse_ctx->client_name) {
+		gss_maj = gss_release_name(&gss_min,
+					   &gse_ctx->client_name);
+	}
+	if (gse_ctx->creds) {
+		gss_maj = gss_release_cred(&gss_min,
+					   &gse_ctx->creds);
+	}
+	if (gse_ctx->delegated_creds) {
+		gss_maj = gss_release_cred(&gss_min,
+					   &gse_ctx->delegated_creds);
+	}
+	if (gse_ctx->ret_mech) {
+		gss_maj = gss_release_oid(&gss_min,
+					  &gse_ctx->ret_mech);
+	}
+	return 0;
+}
+
+static NTSTATUS gse_context_init(TALLOC_CTX *mem_ctx,
+				 enum dcerpc_AuthType auth_type,
+				 enum dcerpc_AuthLevel auth_level,
+				 const char *ccache_name,
+				 uint32_t add_gss_c_flags,
+				 struct gse_context **_gse_ctx)
+{
+	struct gse_context *gse_ctx;
+	krb5_error_code k5ret;
+	NTSTATUS status;
+
+	gse_ctx = talloc_zero(mem_ctx, struct gse_context);
+	if (!gse_ctx) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	talloc_set_destructor((TALLOC_CTX *)gse_ctx, gse_context_destructor);
+
+	memcpy(&gse_ctx->gss_mech, gss_mech_krb5, sizeof(gss_OID_desc));
+
+	switch (auth_type) {
+	case DCERPC_AUTH_TYPE_SPNEGO:
+		gse_ctx->spnego_wrap = true;
+		break;
+	case DCERPC_AUTH_TYPE_KRB5:
+		gse_ctx->spnego_wrap = false;
+		break;
+	default:
+		status = NT_STATUS_INVALID_PARAMETER;
+		goto err_out;
+	}
+
+	gse_ctx->gss_c_flags = GSS_C_MUTUAL_FLAG |
+				GSS_C_DELEG_FLAG |
+				GSS_C_DELEG_POLICY_FLAG |
+				GSS_C_REPLAY_FLAG |
+				GSS_C_SEQUENCE_FLAG;
+	switch (auth_level) {
+	case DCERPC_AUTH_LEVEL_INTEGRITY:
+		gse_ctx->gss_c_flags |= GSS_C_INTEG_FLAG;
+		break;
+	case DCERPC_AUTH_LEVEL_PRIVACY:
+		gse_ctx->gss_c_flags |= GSS_C_CONF_FLAG;
+		break;
+	default:
+		break;
+	}
+
+	gse_ctx->gss_c_flags |= add_gss_c_flags;
+
+	/* Initialize Kerberos Context */
+	initialize_krb5_error_table();
+
+	k5ret = krb5_init_context(&gse_ctx->k5ctx);
+	if (k5ret) {
+		DEBUG(0, ("Failed to initialize kerberos context! (%s)\n",
+			  error_message(k5ret)));
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto err_out;
+	}
+
+	if (!ccache_name) {
+		ccache_name = krb5_cc_default_name(gse_ctx->k5ctx);
+	}
+	k5ret = krb5_cc_resolve(gse_ctx->k5ctx, ccache_name,
+				&gse_ctx->ccache);
+	if (k5ret) {
+		DEBUG(1, ("Failed to resolve credential cache! (%s)\n",
+			  error_message(k5ret)));
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto err_out;
+	}
+
+	/* TODO: Should we enforce a enc_types list ?
+	ret = krb5_set_default_tgs_ktypes(gse_ctx->k5ctx, enc_types);
+	*/
+
+	*_gse_ctx = gse_ctx;
+	return NT_STATUS_OK;
+
+err_out:
+	TALLOC_FREE(gse_ctx);
+	return status;
+}
+
+NTSTATUS gse_init_client(TALLOC_CTX *mem_ctx,
+			  enum dcerpc_AuthType auth_type,
+			  enum dcerpc_AuthLevel auth_level,
+			  const char *ccache_name,
+			  const char *server,
+			  const char *service,
+			  const char *username,
+			  const char *password,
+			  uint32_t add_gss_c_flags,
+			  struct gse_context **_gse_ctx)
+{
+	struct gse_context *gse_ctx;
+	OM_uint32 gss_maj, gss_min;
+	gss_buffer_desc name_buffer = {0, NULL};
+	gss_OID_set_desc mech_set;
+	NTSTATUS status;
+
+	if (!server || !service) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	status = gse_context_init(mem_ctx, auth_type, auth_level,
+				  ccache_name, add_gss_c_flags,
+				  &gse_ctx);
+	if (!NT_STATUS_IS_OK(status)) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	name_buffer.value = talloc_asprintf(gse_ctx,
+					    "%s@%s", service, server);
+	if (!name_buffer.value) {
+		status = NT_STATUS_NO_MEMORY;
+		goto err_out;
+	}
+	name_buffer.length = strlen((char *)name_buffer.value);
+	gss_maj = gss_import_name(&gss_min, &name_buffer,
+				  GSS_C_NT_HOSTBASED_SERVICE,
+				  &gse_ctx->server_name);
+	if (gss_maj) {
+		DEBUG(0, ("gss_import_name failed for %s, with [%s]\n",
+			  (char *)name_buffer.value,
+			  gse_errstr(gse_ctx, gss_maj, gss_min)));
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto err_out;
+	}
+
+	/* TODO: get krb5 ticket using username/password, if no valid
+	 * one already available in ccache */
+
+	mech_set.count = 1;
+	mech_set.elements = &gse_ctx->gss_mech;
+
+	gss_maj = gss_acquire_cred(&gss_min,
+				   GSS_C_NO_NAME,
+				   GSS_C_INDEFINITE,
+				   &mech_set,
+				   GSS_C_INITIATE,
+				   &gse_ctx->creds,
+				   NULL, NULL);
+	if (gss_maj) {
+		DEBUG(0, ("gss_acquire_creds failed for %s, with [%s]\n",
+			  (char *)name_buffer.value,
+			  gse_errstr(gse_ctx, gss_maj, gss_min)));
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto err_out;
+	}
+
+	*_gse_ctx = gse_ctx;
+	TALLOC_FREE(name_buffer.value);
+	return NT_STATUS_OK;
+
+err_out:
+	TALLOC_FREE(name_buffer.value);
+	TALLOC_FREE(gse_ctx);
+	return status;
+}
+
+NTSTATUS gse_get_client_auth_token(TALLOC_CTX *mem_ctx,
+				   struct gse_context *gse_ctx,
+				   DATA_BLOB *token_in,
+				   DATA_BLOB *token_out)
+{
+	OM_uint32 gss_maj, gss_min;
+	gss_buffer_desc in_data;
+	gss_buffer_desc out_data;
+	DATA_BLOB blob = data_blob_null;
+	NTSTATUS status;
+
+	in_data.value = token_in->data;
+	in_data.length = token_in->length;
+
+	gss_maj = gss_init_sec_context(&gss_min,
+					gse_ctx->creds,
+					&gse_ctx->gss_ctx,
+					gse_ctx->server_name,
+					&gse_ctx->gss_mech,
+					gse_ctx->gss_c_flags,
+					0, GSS_C_NO_CHANNEL_BINDINGS,
+					&in_data, NULL, &out_data,
+					NULL, NULL);
+	switch (gss_maj) {
+	case GSS_S_COMPLETE:
+		/* we are done with it */
+		gse_ctx->more_processing = false;
+		status = NT_STATUS_OK;
+		break;
+	case GSS_S_CONTINUE_NEEDED:
+		/* we will need a third leg */
+		gse_ctx->more_processing = true;
+		/* status = NT_STATUS_MORE_PROCESSING_REQUIRED; */
+		status = NT_STATUS_OK;
+		break;
+	default:
+		DEBUG(0, ("gss_init_sec_context failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto done;
+	}
+
+	blob = data_blob_talloc(mem_ctx, out_data.value, out_data.length);
+	if (!blob.data) {
+		status = NT_STATUS_NO_MEMORY;
+	}
+
+	gss_maj = gss_release_buffer(&gss_min, &out_data);
+
+done:
+	*token_out = blob;
+	return status;
+}
+
+NTSTATUS gse_init_server(TALLOC_CTX *mem_ctx,
+			 enum dcerpc_AuthType auth_type,
+			 enum dcerpc_AuthLevel auth_level,
+			 uint32_t add_gss_c_flags,
+			 const char *server,
+			 const char *keytab_name,
+			 struct gse_context **_gse_ctx)
+{
+	struct gse_context *gse_ctx;
+	OM_uint32 gss_maj, gss_min;
+	gss_OID_set_desc mech_set;
+	krb5_error_code ret;
+	const char *ktname;
+	NTSTATUS status;
+
+	status = gse_context_init(mem_ctx, auth_type, auth_level,
+				  NULL, add_gss_c_flags, &gse_ctx);
+	if (!NT_STATUS_IS_OK(status)) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (!keytab_name) {
+		ret = gse_krb5_get_server_keytab(gse_ctx->k5ctx,
+						 &gse_ctx->keytab);
+		if (ret) {
+			status = NT_STATUS_INTERNAL_ERROR;
+			goto done;
+		}
+		ret = smb_krb5_keytab_name(gse_ctx, gse_ctx->k5ctx,
+					   gse_ctx->keytab, &ktname);
+		if (ret) {
+			status = NT_STATUS_INTERNAL_ERROR;
+			goto done;
+		}
+	} else {
+		ktname = keytab_name;
+	}
+
+	/* FIXME!!!
+	 * This call sets the default keytab for the whole server, not
+	 * just for this context. Need to find a way that does not alter
+	 * the state of the whole server ... */
+	ret = gsskrb5_register_acceptor_identity(ktname);
+	if (ret) {
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto done;
+	}
+
+	mech_set.count = 1;
+	mech_set.elements = &gse_ctx->gss_mech;
+
+	gss_maj = gss_acquire_cred(&gss_min,
+				   GSS_C_NO_NAME,
+				   GSS_C_INDEFINITE,
+				   &mech_set,
+				   GSS_C_ACCEPT,
+				   &gse_ctx->creds,
+				   NULL, NULL);
+	if (gss_maj) {
+		DEBUG(0, ("gss_acquire_creds failed with [%s]\n",
+			  gse_errstr(gse_ctx, gss_maj, gss_min)));
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto done;
+	}
+
+	status = NT_STATUS_OK;
+
+done:
+	if (!NT_STATUS_IS_OK(status)) {
+		TALLOC_FREE(gse_ctx);
+	}
+
+	*_gse_ctx = gse_ctx;
+	return status;
+}
+
+NTSTATUS gse_get_server_auth_token(TALLOC_CTX *mem_ctx,
+				   struct gse_context *gse_ctx,
+				   DATA_BLOB *token_in,
+				   DATA_BLOB *token_out)
+{
+	OM_uint32 gss_maj, gss_min;
+	gss_buffer_desc in_data;
+	gss_buffer_desc out_data;
+	DATA_BLOB blob = data_blob_null;
+	NTSTATUS status;
+
+	in_data.value = token_in->data;
+	in_data.length = token_in->length;
+
+	gss_maj = gss_accept_sec_context(&gss_min,
+					 &gse_ctx->gss_ctx,
+					 gse_ctx->creds,
+					 &in_data,
+					 GSS_C_NO_CHANNEL_BINDINGS,
+					 &gse_ctx->client_name,
+					 &gse_ctx->ret_mech,
+					 &out_data,
+					 &gse_ctx->ret_flags, NULL,
+					 &gse_ctx->delegated_creds);
+	switch (gss_maj) {
+	case GSS_S_COMPLETE:
+		/* we are done with it */
+		gse_ctx->more_processing = false;
+		gse_ctx->authenticated = true;
+		status = NT_STATUS_OK;
+		break;
+	case GSS_S_CONTINUE_NEEDED:
+		/* we will need a third leg */
+		gse_ctx->more_processing = true;
+		/* status = NT_STATUS_MORE_PROCESSING_REQUIRED; */
+		status = NT_STATUS_OK;
+		break;
+	default:
+		DEBUG(0, ("gss_init_sec_context failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+
+		if (gse_ctx->gss_ctx) {
+			gss_delete_sec_context(&gss_min,
+						&gse_ctx->gss_ctx,
+						GSS_C_NO_BUFFER);
+		}
+
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto done;
+	}
+
+	/* we may be told to return nothing */
+	if (out_data.length) {
+		blob = data_blob_talloc(mem_ctx, out_data.value, out_data.length);
+		if (!blob.data) {
+			status = NT_STATUS_NO_MEMORY;
+		}
+		gss_maj = gss_release_buffer(&gss_min, &out_data);
+	}
+
+
+done:
+	*token_out = blob;
+	return status;
+}
+
+NTSTATUS gse_verify_server_auth_flags(struct gse_context *gse_ctx)
+{
+	if (!gse_ctx->authenticated) {
+		return NT_STATUS_INVALID_HANDLE;
+	}
+
+	if (memcmp(gse_ctx->ret_mech,
+		   gss_mech_krb5, sizeof(gss_OID_desc)) != 0) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	/* GSS_C_MUTUAL_FLAG */
+	if (gse_ctx->gss_c_flags & GSS_C_MUTUAL_FLAG) {
+		if (!(gse_ctx->ret_flags & GSS_C_MUTUAL_FLAG)) {
+			return NT_STATUS_ACCESS_DENIED;
+		}
+	}
+
+	/* GSS_C_DELEG_FLAG */
+	/* GSS_C_DELEG_POLICY_FLAG */
+	/* GSS_C_REPLAY_FLAG */
+	/* GSS_C_SEQUENCE_FLAG */
+
+	/* GSS_C_INTEG_FLAG */
+	if (gse_ctx->gss_c_flags & GSS_C_INTEG_FLAG) {
+		if (!(gse_ctx->ret_flags & GSS_C_INTEG_FLAG)) {
+			return NT_STATUS_ACCESS_DENIED;
+		}
+	}
+
+	/* GSS_C_CONF_FLAG */
+	if (gse_ctx->gss_c_flags & GSS_C_CONF_FLAG) {
+		if (!(gse_ctx->ret_flags & GSS_C_CONF_FLAG)) {
+			return NT_STATUS_ACCESS_DENIED;
+		}
+	}
+
+	return NT_STATUS_OK;
+}
+
+static char *gse_errstr(TALLOC_CTX *mem_ctx, OM_uint32 maj, OM_uint32 min)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_desc msg_min;
+	gss_buffer_desc msg_maj;
+	OM_uint32 msg_ctx = 0;
+
+	char *errstr = NULL;
+
+	ZERO_STRUCT(msg_min);
+	ZERO_STRUCT(msg_maj);
+
+	gss_maj = gss_display_status(&gss_min, maj, GSS_C_GSS_CODE,
+				     GSS_C_NO_OID, &msg_ctx, &msg_maj);
+	if (gss_maj) {
+		goto done;
+	}
+	gss_maj = gss_display_status(&gss_min, min, GSS_C_MECH_CODE,
+				     (gss_OID)discard_const(gss_mech_krb5),
+				     &msg_ctx, &msg_min);
+	if (gss_maj) {
+		goto done;
+	}
+
+	errstr = talloc_strndup(mem_ctx,
+				(char *)msg_maj.value,
+					msg_maj.length);
+	if (!errstr) {
+		goto done;
+	}
+	errstr = talloc_strdup_append_buffer(errstr, ": ");
+	if (!errstr) {
+		goto done;
+	}
+	errstr = talloc_strndup_append_buffer(errstr,
+						(char *)msg_min.value,
+							msg_min.length);
+	if (!errstr) {
+		goto done;
+	}
+
+done:
+	if (msg_min.value) {
+		gss_maj = gss_release_buffer(&gss_min, &msg_min);
+	}
+	if (msg_maj.value) {
+		gss_maj = gss_release_buffer(&gss_min, &msg_maj);
+	}
+	return errstr;
+}
+
+bool gse_require_more_processing(struct gse_context *gse_ctx)
+{
+	return gse_ctx->more_processing;
+}
+
+DATA_BLOB gse_get_session_key(TALLOC_CTX *mem_ctx,
+				struct gse_context *gse_ctx)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
+	DATA_BLOB ret;
+
+	gss_maj = gss_inquire_sec_context_by_oid(
+				&gss_min, gse_ctx->gss_ctx,
+				&gse_sesskey_inq_oid, &set);
+	if (gss_maj) {
+		DEBUG(0, ("gss_inquire_sec_context_by_oid failed [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		return data_blob_null;
+	}
+
+	if ((set == GSS_C_NO_BUFFER_SET) ||
+	    (set->count != 2) ||
+	    (memcmp(set->elements[1].value,
+		    gse_sesskeytype_oid.elements,
+		    gse_sesskeytype_oid.length) != 0)) {
+		DEBUG(0, ("gss_inquire_sec_context_by_oid returned unknown "
+			  "OID for data in results:\n"));
+		dump_data(1, (uint8_t *)set->elements[1].value,
+			     set->elements[1].length);
+		return data_blob_null;
+	}
+
+	ret = data_blob_talloc(mem_ctx, set->elements[0].value,
+					set->elements[0].length);
+
+	gss_maj = gss_release_buffer_set(&gss_min, &set);
+	return ret;
+}
+
+NTSTATUS gse_get_client_name(struct gse_context *gse_ctx,
+			     TALLOC_CTX *mem_ctx, char **cli_name)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_desc name_buffer;
+
+	if (!gse_ctx->authenticated) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	if (!gse_ctx->client_name) {
+		return NT_STATUS_NOT_FOUND;
+	}
+
+	/* TODO: check OID matches KRB5 Principal Name OID ? */
+
+	gss_maj = gss_display_name(&gss_min,
+				   gse_ctx->client_name,
+				   &name_buffer, NULL);
+	if (gss_maj) {
+		DEBUG(0, ("gss_display_name failed [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	*cli_name = talloc_strndup(talloc_tos(),
+					(char *)name_buffer.value,
+					name_buffer.length);
+
+	gss_maj = gss_release_buffer(&gss_min, &name_buffer);
+
+	if (!*cli_name) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	return NT_STATUS_OK;
+}
+
+NTSTATUS gse_get_authz_data(struct gse_context *gse_ctx,
+			    TALLOC_CTX *mem_ctx, DATA_BLOB *pac)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
+
+	if (!gse_ctx->authenticated) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	gss_maj = gss_inquire_sec_context_by_oid(
+				&gss_min, gse_ctx->gss_ctx,
+				&gse_authz_data_oid, &set);
+	if (gss_maj) {
+		DEBUG(0, ("gss_inquire_sec_context_by_oid failed [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		return NT_STATUS_NOT_FOUND;
+	}
+
+	if (set == GSS_C_NO_BUFFER_SET) {
+		DEBUG(0, ("gss_inquire_sec_context_by_oid returned unknown "
+			  "data in results.\n"));
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	/* for now we just hope it is the first value */
+	*pac = data_blob_talloc(mem_ctx,
+				set->elements[0].value,
+				set->elements[0].length);
+
+	gss_maj = gss_release_buffer_set(&gss_min, &set);
+
+	return NT_STATUS_OK;
+}
+
+NTSTATUS gse_get_authtime(struct gse_context *gse_ctx, time_t *authtime)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
+	int32_t	tkttime;
+
+	if (!gse_ctx->authenticated) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	gss_maj = gss_inquire_sec_context_by_oid(
+				&gss_min, gse_ctx->gss_ctx,
+				&gse_authtime_oid, &set);
+	if (gss_maj) {
+		DEBUG(0, ("gss_inquire_sec_context_by_oid failed [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		return NT_STATUS_NOT_FOUND;
+	}
+
+	if ((set == GSS_C_NO_BUFFER_SET) || (set->count != 1) != 0) {
+		DEBUG(0, ("gss_inquire_sec_context_by_oid returned unknown "
+			  "data in results.\n"));
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	if (set->elements[0].length != sizeof(int32_t)) {
+		DEBUG(0, ("Invalid authtime size!\n"));
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	tkttime = *((int32_t *)set->elements[0].value);
+
+	gss_maj = gss_release_buffer_set(&gss_min, &set);
+
+	*authtime = (time_t)tkttime;
+	return NT_STATUS_OK;
+}
+
+size_t gse_get_signature_length(struct gse_context *gse_ctx,
+				int seal, size_t payload_size)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_iov_buffer_desc iov[2];
+	uint8_t fakebuf[payload_size];
+	int sealed;
+
+	iov[0].type = GSS_IOV_BUFFER_TYPE_HEADER;
+	iov[0].buffer.value = NULL;
+	iov[0].buffer.length = 0;
+	iov[1].type = GSS_IOV_BUFFER_TYPE_DATA;
+	iov[1].buffer.value = fakebuf;
+	iov[1].buffer.length = payload_size;
+
+	gss_maj = gss_wrap_iov_length(&gss_min, gse_ctx->gss_ctx,
+					seal, GSS_C_QOP_DEFAULT,
+					&sealed, iov, 2);
+	if (gss_maj) {
+		DEBUG(0, ("gss_wrap_iov_length failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		return 0;
+	}
+
+	return iov[0].buffer.length;
+}
+
+NTSTATUS gse_seal(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		  DATA_BLOB *data, DATA_BLOB *signature)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_iov_buffer_desc iov[2];
+	int req_seal = 1; /* setting to 1 means we request sign+seal */
+	int sealed;
+	NTSTATUS status;
+
+	/* allocate the memory ourselves so we do not need to talloc_memdup */
+	signature->length = gse_get_signature_length(gse_ctx, 1, data->length);
+	if (!signature->length) {
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+	signature->data = (uint8_t *)talloc_size(mem_ctx, signature->length);
+	if (!signature->data) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	iov[0].type = GSS_IOV_BUFFER_TYPE_HEADER;
+	iov[0].buffer.value = signature->data;
+	iov[0].buffer.length = signature->length;
+
+	/* data is encrypted in place, which is ok */
+	iov[1].type = GSS_IOV_BUFFER_TYPE_DATA;
+	iov[1].buffer.value = data->data;
+	iov[1].buffer.length = data->length;
+
+	gss_maj = gss_wrap_iov(&gss_min, gse_ctx->gss_ctx,
+				req_seal, GSS_C_QOP_DEFAULT,
+				&sealed, iov, 2);
+	if (gss_maj) {
+		DEBUG(0, ("gss_wrap_iov failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	if (!sealed) {
+		DEBUG(0, ("gss_wrap_iov says data was not sealed!\n"));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	status = NT_STATUS_OK;
+
+	DEBUG(10, ("Sealed %d bytes, and got %d bytes header/signature.\n",
+		   (int)iov[1].buffer.length, (int)iov[0].buffer.length));
+
+done:
+	return status;
+}
+
+NTSTATUS gse_unseal(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		    DATA_BLOB *data, DATA_BLOB *signature)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_iov_buffer_desc iov[2];
+	int sealed;
+	NTSTATUS status;
+
+	iov[0].type = GSS_IOV_BUFFER_TYPE_HEADER;
+	iov[0].buffer.value = signature->data;
+	iov[0].buffer.length = signature->length;
+
+	/* data is decrypted in place, which is ok */
+	iov[1].type = GSS_IOV_BUFFER_TYPE_DATA;
+	iov[1].buffer.value = data->data;
+	iov[1].buffer.length = data->length;
+
+	gss_maj = gss_unwrap_iov(&gss_min, gse_ctx->gss_ctx,
+				 &sealed, NULL, iov, 2);
+	if (gss_maj) {
+		DEBUG(0, ("gss_unwrap_iov failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	if (!sealed) {
+		DEBUG(0, ("gss_unwrap_iov says data is not sealed!\n"));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	status = NT_STATUS_OK;
+
+	DEBUG(10, ("Unsealed %d bytes, with %d bytes header/signature.\n",
+		   (int)iov[1].buffer.length, (int)iov[0].buffer.length));
+
+done:
+	return status;
+}
+
+NTSTATUS gse_sign(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		  DATA_BLOB *data, DATA_BLOB *signature)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_desc in_data = { 0, NULL };
+	gss_buffer_desc out_data = { 0, NULL};
+	NTSTATUS status;
+
+	in_data.value = data->data;
+	in_data.length = data->length;
+
+	gss_maj = gss_get_mic(&gss_min, gse_ctx->gss_ctx,
+			      GSS_C_QOP_DEFAULT,
+			      &in_data, &out_data);
+	if (gss_maj) {
+		DEBUG(0, ("gss_get_mic failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	*signature = data_blob_talloc(mem_ctx,
+					out_data.value, out_data.length);
+	if (!signature->data) {
+		status = NT_STATUS_NO_MEMORY;
+		goto done;
+	}
+
+	status = NT_STATUS_OK;
+
+done:
+	if (out_data.value) {
+		gss_maj = gss_release_buffer(&gss_min, &out_data);
+	}
+	return status;
+}
+
+NTSTATUS gse_sigcheck(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		      DATA_BLOB *data, DATA_BLOB *signature)
+{
+	OM_uint32 gss_min, gss_maj;
+	gss_buffer_desc in_data = { 0, NULL };
+	gss_buffer_desc in_token = { 0, NULL};
+	NTSTATUS status;
+
+	in_data.value = data->data;
+	in_data.length = data->length;
+	in_token.value = signature->data;
+	in_token.length = signature->length;
+
+	gss_maj = gss_verify_mic(&gss_min, gse_ctx->gss_ctx,
+				 &in_data, &in_token, NULL);
+	if (gss_maj) {
+		DEBUG(0, ("gss_verify_mic failed with [%s]\n",
+			  gse_errstr(talloc_tos(), gss_maj, gss_min)));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	status = NT_STATUS_OK;
+
+done:
+	return status;
+}
+
+#else
+
+NTSTATUS gse_init_client(TALLOC_CTX *mem_ctx,
+			  enum dcerpc_AuthType auth_type,
+			  enum dcerpc_AuthLevel auth_level,
+			  const char *ccache_name,
+			  const char *server,
+			  const char *service,
+			  const char *username,
+			  const char *password,
+			  uint32_t add_gss_c_flags,
+			  struct gse_context **_gse_ctx)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_get_client_auth_token(TALLOC_CTX *mem_ctx,
+				   struct gse_context *gse_ctx,
+				   DATA_BLOB *token_in,
+				   DATA_BLOB *token_out)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_init_server(TALLOC_CTX *mem_ctx,
+			 enum dcerpc_AuthType auth_type,
+			 enum dcerpc_AuthLevel auth_level,
+			 uint32_t add_gss_c_flags,
+			 const char *server,
+			 const char *keytab,
+			 struct gse_context **_gse_ctx)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_get_server_auth_token(TALLOC_CTX *mem_ctx,
+				   struct gse_context *gse_ctx,
+				   DATA_BLOB *token_in,
+				   DATA_BLOB *token_out)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_verify_server_auth_flags(struct gse_context *gse_ctx)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+bool gse_require_more_processing(struct gse_context *gse_ctx)
+{
+	return false;
+}
+
+DATA_BLOB gse_get_session_key(TALLOC_CTX *mem_ctx,
+			      struct gse_context *gse_ctx)
+{
+	return data_blob_null;
+}
+
+NTSTATUS gse_get_client_name(struct gse_context *gse_ctx,
+			     TALLOC_CTX *mem_ctx, char **cli_name)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_get_authz_data(struct gse_context *gse_ctx,
+			    TALLOC_CTX *mem_ctx, DATA_BLOB *pac)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_get_authtime(struct gse_context *gse_ctx, time_t *authtime)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+size_t gse_get_signature_length(struct gse_context *gse_ctx,
+				int seal, size_t payload_size)
+{
+	return 0;
+}
+
+NTSTATUS gse_seal(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		  DATA_BLOB *data, DATA_BLOB *signature)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_unseal(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		    DATA_BLOB *data, DATA_BLOB *signature)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_sign(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		  DATA_BLOB *data, DATA_BLOB *signature)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+NTSTATUS gse_sigcheck(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		      DATA_BLOB *data, DATA_BLOB *signature)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+#endif /* HAVE_KRB5 && HAVE_GSSAPI_EXT_H && HAVE_GSS_WRAP_IOV */
diff --git a/source3/librpc/crypto/gse.h b/source3/librpc/crypto/gse.h
new file mode 100644
index 0000000000..6f8b6735ad
--- /dev/null
+++ b/source3/librpc/crypto/gse.h
@@ -0,0 +1,77 @@
+/*
+ *  GSSAPI Security Extensions
+ *  RPC Pipe client routines
+ *  Copyright (C) Simo Sorce 2010.
+ *
+ *  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 _GSE_H_
+#define _GSE_H_
+
+struct gse_context;
+
+#ifndef GSS_C_DCE_STYLE
+#define GSS_C_DCE_STYLE 0x1000
+#endif
+
+NTSTATUS gse_init_client(TALLOC_CTX *mem_ctx,
+			  enum dcerpc_AuthType auth_type,
+			  enum dcerpc_AuthLevel auth_level,
+			  const char *ccache_name,
+			  const char *server,
+			  const char *service,
+			  const char *username,
+			  const char *password,
+			  uint32_t add_gss_c_flags,
+			  struct gse_context **_gse_ctx);
+NTSTATUS gse_get_client_auth_token(TALLOC_CTX *mem_ctx,
+				   struct gse_context *gse_ctx,
+				   DATA_BLOB *token_in,
+				   DATA_BLOB *token_out);
+
+NTSTATUS gse_init_server(TALLOC_CTX *mem_ctx,
+			 enum dcerpc_AuthType auth_type,
+			 enum dcerpc_AuthLevel auth_level,
+			 uint32_t add_gss_c_flags,
+			 const char *server,
+			 const char *keytab,
+			 struct gse_context **_gse_ctx);
+NTSTATUS gse_get_server_auth_token(TALLOC_CTX *mem_ctx,
+				   struct gse_context *gse_ctx,
+				   DATA_BLOB *token_in,
+				   DATA_BLOB *token_out);
+NTSTATUS gse_verify_server_auth_flags(struct gse_context *gse_ctx);
+
+bool gse_require_more_processing(struct gse_context *gse_ctx);
+DATA_BLOB gse_get_session_key(TALLOC_CTX *mem_ctx,
+				struct gse_context *gse_ctx);
+NTSTATUS gse_get_client_name(struct gse_context *gse_ctx,
+			     TALLOC_CTX *mem_ctx, char **client_name);
+NTSTATUS gse_get_authz_data(struct gse_context *gse_ctx,
+			    TALLOC_CTX *mem_ctx, DATA_BLOB *pac);
+NTSTATUS gse_get_authtime(struct gse_context *gse_ctx, time_t *authtime);
+
+size_t gse_get_signature_length(struct gse_context *gse_ctx,
+				int seal, size_t payload_size);
+NTSTATUS gse_seal(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		  DATA_BLOB *data, DATA_BLOB *signature);
+NTSTATUS gse_unseal(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		    DATA_BLOB *data, DATA_BLOB *signature);
+NTSTATUS gse_sign(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		  DATA_BLOB *data, DATA_BLOB *signature);
+NTSTATUS gse_sigcheck(TALLOC_CTX *mem_ctx, struct gse_context *gse_ctx,
+		      DATA_BLOB *data, DATA_BLOB *signature);
+
+#endif /* _GSE_H_ */
diff --git a/source3/librpc/crypto/gse_krb5.c b/source3/librpc/crypto/gse_krb5.c
new file mode 100644
index 0000000000..735dff059e
--- /dev/null
+++ b/source3/librpc/crypto/gse_krb5.c
@@ -0,0 +1,388 @@
+/*
+ *  GSSAPI Security Extensions
+ *  Krb5 helpers
+ *  Copyright (C) Simo Sorce 2010.
+ *
+ *  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 "smb_krb5.h"
+#include "secrets.h"
+#include "gse_krb5.h"
+
+#ifdef HAVE_KRB5
+
+static krb5_error_code flush_keytab(krb5_context krbctx, krb5_keytab keytab)
+{
+	krb5_error_code ret;
+	krb5_kt_cursor kt_cursor;
+	krb5_keytab_entry kt_entry;
+
+	ZERO_STRUCT(kt_entry);
+
+	ret = krb5_kt_start_seq_get(krbctx, keytab, &kt_cursor);
+	if (ret == KRB5_KT_END || ret == ENOENT ) {
+		/* no entries */
+		return 0;
+	}
+
+	ret = krb5_kt_next_entry(krbctx, keytab, &kt_entry, &kt_cursor);
+	while (ret == 0) {
+
+		/* we need to close and reopen enumeration because we modify
+		 * the keytab */
+		ret = krb5_kt_end_seq_get(krbctx, keytab, &kt_cursor);
+		if (ret) {
+			DEBUG(1, (__location__ ": krb5_kt_end_seq_get() "
+				  "failed (%s)\n", error_message(ret)));
+			goto out;
+		}
+
+		/* remove the entry */
+		ret = krb5_kt_remove_entry(krbctx, keytab, &kt_entry);
+		if (ret) {
+			DEBUG(1, (__location__ ": krb5_kt_remove_entry() "
+				  "failed (%s)\n", error_message(ret)));
+			goto out;
+		}
+		ret = smb_krb5_kt_free_entry(krbctx, &kt_entry);
+		ZERO_STRUCT(kt_entry);
+
+		/* now reopen */
+		ret = krb5_kt_start_seq_get(krbctx, keytab, &kt_cursor);
+		if (ret) {
+			DEBUG(1, (__location__ ": krb5_kt_start_seq() failed "
+				  "(%s)\n", error_message(ret)));
+			goto out;
+		}
+
+		ret = krb5_kt_next_entry(krbctx, keytab,
+					 &kt_entry, &kt_cursor);
+	}
+
+	if (ret != KRB5_KT_END && ret != ENOENT) {
+		DEBUG(1, (__location__ ": flushing keytab we got [%s]!\n",
+			  error_message(ret)));
+	}
+
+	ret = 0;
+
+out:
+	return ret;
+}
+
+static krb5_error_code get_host_principal(krb5_context krbctx,
+					  krb5_principal *host_princ)
+{
+	krb5_error_code ret;
+	char *host_princ_s = NULL;
+	int err;
+
+	err = asprintf(&host_princ_s, "%s$@%s", global_myname(), lp_realm());
+	if (err == -1) {
+		return -1;
+	}
+
+	strlower_m(host_princ_s);
+	ret = smb_krb5_parse_name(krbctx, host_princ_s, host_princ);
+	if (ret) {
+		DEBUG(1, (__location__ ": smb_krb5_parse_name(%s) "
+			  "failed (%s)\n",
+			  host_princ_s, error_message(ret)));
+	}
+
+	SAFE_FREE(host_princ_s);
+	return ret;
+}
+
+static krb5_error_code fill_keytab_from_password(krb5_context krbctx,
+						 krb5_keytab keytab,
+						 krb5_principal princ,
+						 krb5_kvno vno,
+						 krb5_data *password)
+{
+	krb5_error_code ret;
+	krb5_enctype *enctypes;
+	krb5_keytab_entry kt_entry;
+	unsigned int i;
+
+	ret = get_kerberos_allowed_etypes(krbctx, &enctypes);
+	if (ret) {
+		DEBUG(1, (__location__
+			  ": Can't determine permitted enctypes!\n"));
+		return ret;
+	}
+
+	for (i = 0; enctypes[i]; i++) {
+		krb5_keyblock *key = NULL;
+
+		if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
+			ret = ENOMEM;
+			goto out;
+		}
+
+		if (create_kerberos_key_from_string(krbctx, princ,
+						    password, key,
+						    enctypes[i], false)) {
+			DEBUG(10, ("Failed to create key for enctype %d "
+				   "(error: %s)\n",
+				   enctypes[i], error_message(ret)));
+			SAFE_FREE(key);
+			continue;
+		}
+
+		kt_entry.principal = princ;
+		kt_entry.vno = vno;
+		*(KRB5_KT_KEY(&kt_entry)) = *key;
+
+		ret = krb5_kt_add_entry(krbctx, keytab, &kt_entry);
+		if (ret) {
+			DEBUG(1, (__location__ ": Failed to add entry to "
+				  "keytab for enctype %d (error: %s)\n",
+				   enctypes[i], error_message(ret)));
+			krb5_free_keyblock(krbctx, key);
+			goto out;
+		}
+
+		krb5_free_keyblock(krbctx, key);
+	}
+
+	ret = 0;
+
+out:
+	SAFE_FREE(enctypes);
+	return ret;
+}
+
+#define SRV_MEM_KEYTAB_NAME "MEMORY:cifs_srv_keytab"
+#define CLEARTEXT_PRIV_ENCTYPE -99
+
+static krb5_error_code get_mem_keytab_from_secrets(krb5_context krbctx,
+						   krb5_keytab *keytab)
+{
+	krb5_error_code ret;
+	char *pwd = NULL;
+	size_t pwd_len;
+	krb5_kt_cursor kt_cursor;
+	krb5_keytab_entry kt_entry;
+	krb5_data password;
+	krb5_principal princ = NULL;
+	krb5_kvno kvno = 0; /* FIXME: fetch current vno from KDC ? */
+	char *pwd_old = NULL;
+
+	if (!secrets_init()) {
+		DEBUG(1, (__location__ ": secrets_init failed\n"));
+		return KRB5_CONFIG_CANTOPEN;
+	}
+
+	pwd = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
+	if (!pwd) {
+		DEBUG(2, (__location__ ": failed to fetch machine password\n"));
+		return KRB5_LIBOS_CANTREADPWD;
+	}
+	pwd_len = strlen(pwd);
+
+	if (*keytab == NULL) {
+		/* create memory keytab */
+		ret = krb5_kt_resolve(krbctx, SRV_MEM_KEYTAB_NAME, keytab);
+		if (ret) {
+			DEBUG(1, (__location__ ": Failed to get memory "
+				  "keytab!\n"));
+			return ret;
+		}
+	}
+
+	ZERO_STRUCT(kt_entry);
+	ZERO_STRUCT(kt_cursor);
+
+	/* check if the keytab already has any entry */
+	ret = krb5_kt_start_seq_get(krbctx, *keytab, &kt_cursor);
+	if (ret != KRB5_KT_END && ret != ENOENT ) {
+		/* check if we have our special enctype used to hold
+		 * the clear text password. If so, check it out so that
+		 * we can verify if the keytab needs to be upgraded */
+		while ((ret = krb5_kt_next_entry(krbctx, *keytab,
+					   &kt_entry, &kt_cursor)) == 0) {
+			if (smb_get_enctype_from_kt_entry(&kt_entry) == CLEARTEXT_PRIV_ENCTYPE) {
+				break;
+			}
+			smb_krb5_kt_free_entry(krbctx, &kt_entry);
+			ZERO_STRUCT(kt_entry);
+		}
+
+		if (ret != 0 && ret != KRB5_KT_END && ret != ENOENT ) {
+			/* Error parsing keytab */
+			DEBUG(1, (__location__ ": Failed to parse memory "
+				  "keytab!\n"));
+			goto out;
+		}
+
+		if (ret == 0) {
+			/* found private entry,
+			 * check if keytab is up to date */
+
+			if ((pwd_len == KRB5_KEY_LENGTH(KRB5_KT_KEY(&kt_entry))) &&
+			    (memcmp(KRB5_KEY_DATA(KRB5_KT_KEY(&kt_entry)),
+						pwd, pwd_len) == 0)) {
+				/* keytab is already up to date, return */
+				smb_krb5_kt_free_entry(krbctx, &kt_entry);
+				goto out;
+			}
+
+			smb_krb5_kt_free_entry(krbctx, &kt_entry);
+			ZERO_STRUCT(kt_entry);
+
+
+			/* flush keytab, we need to regen it */
+			ret = flush_keytab(krbctx, *keytab);
+			if (ret) {
+				DEBUG(1, (__location__ ": Failed to flush "
+					  "memory keytab!\n"));
+				goto out;
+			}
+		}
+	}
+
+	{
+		krb5_kt_cursor zero_csr;
+		ZERO_STRUCT(zero_csr);
+		if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && *keytab) {
+			krb5_kt_end_seq_get(krbctx, *keytab, &kt_cursor);
+		}
+        }
+
+	/* keytab is not up to date, fill it up */
+
+	ret = get_host_principal(krbctx, &princ);
+	if (ret) {
+		DEBUG(1, (__location__ ": Failed to get host principal!\n"));
+		goto out;
+	}
+
+	password.data = pwd;
+	password.length = pwd_len;
+	ret = fill_keytab_from_password(krbctx, *keytab,
+					princ, kvno, &password);
+	if (ret) {
+		DEBUG(1, (__location__ ": Failed to fill memory keytab!\n"));
+		goto out;
+	}
+
+	pwd_old = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
+	if (!pwd_old) {
+		DEBUG(10, (__location__ ": no prev machine password\n"));
+	} else {
+		password.data = pwd_old;
+		password.length = strlen(pwd_old);
+		ret = fill_keytab_from_password(krbctx, *keytab,
+						princ, kvno -1, &password);
+		if (ret) {
+			DEBUG(1, (__location__
+				  ": Failed to fill memory keytab!\n"));
+			goto out;
+		}
+	}
+
+	/* add our private enctype + cleartext password so that we can
+	 * update the keytab if secrets change later on */
+	ZERO_STRUCT(kt_entry);
+	kt_entry.principal = princ;
+	kt_entry.vno = 0;
+
+	KRB5_KEY_TYPE(KRB5_KT_KEY(&kt_entry)) = CLEARTEXT_PRIV_ENCTYPE;
+	KRB5_KEY_LENGTH(KRB5_KT_KEY(&kt_entry)) = pwd_len;
+	KRB5_KEY_DATA(KRB5_KT_KEY(&kt_entry)) = (uint8_t *)pwd;
+
+	ret = krb5_kt_add_entry(krbctx, *keytab, &kt_entry);
+	if (ret) {
+		DEBUG(1, (__location__ ": Failed to add entry to "
+			  "keytab for private enctype (%d) (error: %s)\n",
+			   CLEARTEXT_PRIV_ENCTYPE, error_message(ret)));
+		goto out;
+	}
+
+	ret = 0;
+
+out:
+	SAFE_FREE(pwd);
+	SAFE_FREE(pwd_old);
+
+	{
+		krb5_kt_cursor zero_csr;
+		ZERO_STRUCT(zero_csr);
+		if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && *keytab) {
+			krb5_kt_end_seq_get(krbctx, *keytab, &kt_cursor);
+		}
+        }
+
+	if (princ) {
+		krb5_free_principal(krbctx, princ);
+	}
+
+	if (ret) {
+		if (*keytab) {
+			krb5_kt_close(krbctx, *keytab);
+			*keytab = NULL;
+		}
+	}
+
+	return ret;
+}
+
+static krb5_error_code get_mem_keytab_from_system_keytab(krb5_context krbctx,
+							 krb5_keytab *keytab,
+							 bool verify)
+{
+	return KRB5_KT_NOTFOUND;
+}
+
+krb5_error_code gse_krb5_get_server_keytab(krb5_context krbctx,
+					   krb5_keytab *keytab)
+{
+	krb5_error_code ret;
+
+	*keytab = NULL;
+
+	switch (lp_kerberos_method()) {
+	default:
+	case KERBEROS_VERIFY_SECRETS:
+		ret = get_mem_keytab_from_secrets(krbctx, keytab);
+		break;
+	case KERBEROS_VERIFY_SYSTEM_KEYTAB:
+		ret = get_mem_keytab_from_system_keytab(krbctx, keytab, true);
+		break;
+	case KERBEROS_VERIFY_DEDICATED_KEYTAB:
+		/* just use whatever keytab is configured */
+		ret = get_mem_keytab_from_system_keytab(krbctx, keytab, false);
+		break;
+	case KERBEROS_VERIFY_SECRETS_AND_KEYTAB:
+		ret = get_mem_keytab_from_secrets(krbctx, keytab);
+		if (ret) {
+			DEBUG(3, (__location__ ": Warning! Unable to set mem "
+				  "keytab from secrets!\n"));
+		}
+		/* Now append system keytab keys too */
+		ret = get_mem_keytab_from_system_keytab(krbctx, keytab, true);
+		if (ret) {
+			DEBUG(3, (__location__ ": Warning! Unable to set mem "
+				  "keytab from secrets!\n"));
+		}
+		break;
+	}
+
+	return ret;
+}
+
+#endif /* HAVE_KRB5 */
diff --git a/source3/librpc/crypto/gse_krb5.h b/source3/librpc/crypto/gse_krb5.h
new file mode 100644
index 0000000000..ea789c947a
--- /dev/null
+++ b/source3/librpc/crypto/gse_krb5.h
@@ -0,0 +1,30 @@
+/*
+ *  GSSAPI Security Extensions
+ *  Krb5 helpers
+ *  Copyright (C) Simo Sorce 2010.
+ *
+ *  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 _GSE_KRB5_H_
+#define _GSE_KRB5_H_
+
+#ifdef HAVE_KRB5
+
+krb5_error_code gse_krb5_get_server_keytab(krb5_context krbctx,
+					   krb5_keytab *keytab);
+
+#endif /* HAVE_KRB5 */
+
+#endif /* _GSE_KRB5_H_ */