auth/gensec: move spnego.c to the toplevel

metze

2 files changed, 1407 insertions, 0 deletions

diff --git a/auth/gensec/spnego.c b/auth/gensec/spnego.c
new file mode 100644
index 0000000000..073496b8df
--- /dev/null
+++ b/auth/gensec/spnego.c
@@ -0,0 +1,1400 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   RFC2478 Compliant SPNEGO implementation
+   
+   Copyright (C) Jim McDonough <jmcd@us.ibm.com>      2003
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
+   Copyright (C) Stefan Metzmacher <metze@samba.org>  2004-2008
+
+   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 "../libcli/auth/spnego.h"
+#include "librpc/gen_ndr/ndr_dcerpc.h"
+#include "auth/credentials/credentials.h"
+#include "auth/gensec/gensec.h"
+#include "param/param.h"
+#include "lib/util/asn1.h"
+
+_PUBLIC_ NTSTATUS gensec_spnego_init(void);
+
+enum spnego_state_position {
+	SPNEGO_SERVER_START,
+	SPNEGO_CLIENT_START,
+	SPNEGO_SERVER_TARG,
+	SPNEGO_CLIENT_TARG,
+	SPNEGO_FALLBACK,
+	SPNEGO_DONE
+};
+
+struct spnego_state {
+	enum spnego_message_type expected_packet;
+	enum spnego_state_position state_position;
+	struct gensec_security *sub_sec_security;
+	bool no_response_expected;
+
+	const char *neg_oid;
+
+	DATA_BLOB mech_types;
+
+	/*
+	 * The following is used to implement
+	 * the update token fragmentation
+	 */
+	size_t in_needed;
+	DATA_BLOB in_frag;
+	size_t out_max_length;
+	DATA_BLOB out_frag;
+	NTSTATUS out_status;
+};
+
+
+static NTSTATUS gensec_spnego_client_start(struct gensec_security *gensec_security)
+{
+	struct spnego_state *spnego_state;
+
+	spnego_state = talloc_zero(gensec_security, struct spnego_state);
+	if (!spnego_state) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	spnego_state->expected_packet = SPNEGO_NEG_TOKEN_INIT;
+	spnego_state->state_position = SPNEGO_CLIENT_START;
+	spnego_state->sub_sec_security = NULL;
+	spnego_state->no_response_expected = false;
+	spnego_state->mech_types = data_blob(NULL, 0);
+	spnego_state->out_max_length = gensec_max_update_size(gensec_security);
+	spnego_state->out_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
+
+	gensec_security->private_data = spnego_state;
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_spnego_server_start(struct gensec_security *gensec_security)
+{
+	struct spnego_state *spnego_state;
+
+	spnego_state = talloc_zero(gensec_security, struct spnego_state);
+	if (!spnego_state) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	spnego_state->expected_packet = SPNEGO_NEG_TOKEN_INIT;
+	spnego_state->state_position = SPNEGO_SERVER_START;
+	spnego_state->sub_sec_security = NULL;
+	spnego_state->no_response_expected = false;
+	spnego_state->mech_types = data_blob(NULL, 0);
+	spnego_state->out_max_length = gensec_max_update_size(gensec_security);
+	spnego_state->out_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
+
+	gensec_security->private_data = spnego_state;
+	return NT_STATUS_OK;
+}
+
+/*
+  wrappers for the spnego_*() functions
+*/
+static NTSTATUS gensec_spnego_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 spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_unseal_packet(spnego_state->sub_sec_security, 
+				    data, length, 
+				    whole_pdu, pdu_length,
+				    sig); 
+}
+
+static NTSTATUS gensec_spnego_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 spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_check_packet(spnego_state->sub_sec_security, 
+				   data, length, 
+				   whole_pdu, pdu_length,
+				   sig);
+}
+
+static NTSTATUS gensec_spnego_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 spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_seal_packet(spnego_state->sub_sec_security, 
+				  mem_ctx, 
+				  data, length, 
+				  whole_pdu, pdu_length,
+				  sig);
+}
+
+static NTSTATUS gensec_spnego_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 spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_sign_packet(spnego_state->sub_sec_security, 
+				  mem_ctx, 
+				  data, length, 
+				  whole_pdu, pdu_length,
+				  sig);
+}
+
+static NTSTATUS gensec_spnego_wrap(struct gensec_security *gensec_security, 
+				   TALLOC_CTX *mem_ctx, 
+				   const DATA_BLOB *in, 
+				   DATA_BLOB *out)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		DEBUG(1, ("gensec_spnego_wrap: wrong state for wrap\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_wrap(spnego_state->sub_sec_security, 
+			   mem_ctx, in, out);
+}
+
+static NTSTATUS gensec_spnego_unwrap(struct gensec_security *gensec_security, 
+				     TALLOC_CTX *mem_ctx, 
+				     const DATA_BLOB *in, 
+				     DATA_BLOB *out)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		DEBUG(1, ("gensec_spnego_unwrap: wrong state for unwrap\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_unwrap(spnego_state->sub_sec_security, 
+			     mem_ctx, in, out);
+}
+
+static NTSTATUS gensec_spnego_wrap_packets(struct gensec_security *gensec_security, 
+					   TALLOC_CTX *mem_ctx, 
+					   const DATA_BLOB *in, 
+					   DATA_BLOB *out,
+					   size_t *len_processed) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		DEBUG(1, ("gensec_spnego_wrap: wrong state for wrap\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_wrap_packets(spnego_state->sub_sec_security, 
+				   mem_ctx, in, out,
+				   len_processed);
+}
+
+static NTSTATUS gensec_spnego_packet_full_request(struct gensec_security *gensec_security, 
+					     	DATA_BLOB blob, size_t *size)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		DEBUG(1, ("gensec_spnego_unwrap: wrong state for unwrap\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_packet_full_request(spnego_state->sub_sec_security, 
+					  blob, size);
+}
+
+static NTSTATUS gensec_spnego_unwrap_packets(struct gensec_security *gensec_security, 
+					     TALLOC_CTX *mem_ctx, 
+					     const DATA_BLOB *in, 
+					     DATA_BLOB *out,
+					     size_t *len_processed) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		DEBUG(1, ("gensec_spnego_unwrap: wrong state for unwrap\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_unwrap_packets(spnego_state->sub_sec_security, 
+				     mem_ctx, in, out,
+				     len_processed);
+}
+
+static size_t gensec_spnego_sig_size(struct gensec_security *gensec_security, size_t data_size) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return 0;
+	}
+	
+	return gensec_sig_size(spnego_state->sub_sec_security, data_size);
+}
+
+static size_t gensec_spnego_max_input_size(struct gensec_security *gensec_security) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return 0;
+	}
+	
+	return gensec_max_input_size(spnego_state->sub_sec_security);
+}
+
+static size_t gensec_spnego_max_wrapped_size(struct gensec_security *gensec_security) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (spnego_state->state_position != SPNEGO_DONE 
+	    && spnego_state->state_position != SPNEGO_FALLBACK) {
+		return 0;
+	}
+	
+	return gensec_max_wrapped_size(spnego_state->sub_sec_security);
+}
+
+static NTSTATUS gensec_spnego_session_key(struct gensec_security *gensec_security, 
+					  TALLOC_CTX *mem_ctx,
+					  DATA_BLOB *session_key)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	if (!spnego_state->sub_sec_security) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_session_key(spnego_state->sub_sec_security, 
+				  mem_ctx,
+				  session_key);
+}
+
+static NTSTATUS gensec_spnego_session_info(struct gensec_security *gensec_security,
+					   TALLOC_CTX *mem_ctx,
+					   struct auth_session_info **session_info)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	if (!spnego_state->sub_sec_security) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return gensec_session_info(spnego_state->sub_sec_security, 
+				   mem_ctx,
+				   session_info);
+}
+
+/** Fallback to another GENSEC mechanism, based on magic strings 
+ *
+ * This is the 'fallback' case, where we don't get SPNEGO, and have to
+ * try all the other options (and hope they all have a magic string
+ * they check)
+*/
+
+static NTSTATUS gensec_spnego_server_try_fallback(struct gensec_security *gensec_security, 
+						  struct spnego_state *spnego_state,
+						  struct tevent_context *ev,
+						  TALLOC_CTX *out_mem_ctx, 
+						  const DATA_BLOB in, DATA_BLOB *out) 
+{
+	int i,j;
+	struct gensec_security_ops **all_ops
+		= gensec_security_mechs(gensec_security, out_mem_ctx);
+	for (i=0; all_ops[i]; i++) {
+		bool is_spnego;
+		NTSTATUS nt_status;
+
+	    	if (gensec_security != NULL && 
+				!gensec_security_ops_enabled(all_ops[i], gensec_security))
+		    continue;
+
+		if (!all_ops[i]->oid) {
+			continue;
+		}
+
+		is_spnego = false;
+		for (j=0; all_ops[i]->oid[j]; j++) {
+			if (strcasecmp(GENSEC_OID_SPNEGO,all_ops[i]->oid[j]) == 0) {
+				is_spnego = true;
+			}
+		}
+		if (is_spnego) {
+			continue;
+		}
+
+		if (!all_ops[i]->magic) {
+			continue;
+		}
+
+		nt_status = all_ops[i]->magic(gensec_security, &in);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			continue;
+		}
+
+		spnego_state->state_position = SPNEGO_FALLBACK;
+
+		nt_status = gensec_subcontext_start(spnego_state, 
+						    gensec_security, 
+						    &spnego_state->sub_sec_security);
+
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			return nt_status;
+		}
+		/* select the sub context */
+		nt_status = gensec_start_mech_by_ops(spnego_state->sub_sec_security,
+						     all_ops[i]);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			return nt_status;
+		}
+		nt_status = gensec_update(spnego_state->sub_sec_security,
+					  ev, out_mem_ctx, in, out);
+		return nt_status;
+	}
+	DEBUG(1, ("Failed to parse SPNEGO request\n"));
+	return NT_STATUS_INVALID_PARAMETER;
+	
+}
+
+/* 
+   Parse the netTokenInit, either from the client, to the server, or
+   from the server to the client.
+*/
+
+static NTSTATUS gensec_spnego_parse_negTokenInit(struct gensec_security *gensec_security,
+						 struct spnego_state *spnego_state, 
+						 TALLOC_CTX *out_mem_ctx, 
+						 struct tevent_context *ev,
+						 const char **mechType,
+						 const DATA_BLOB unwrapped_in, DATA_BLOB *unwrapped_out) 
+{
+	int i;
+	NTSTATUS nt_status = NT_STATUS_INVALID_PARAMETER;
+	DATA_BLOB null_data_blob = data_blob(NULL,0);
+	bool ok;
+
+	const struct gensec_security_ops_wrapper *all_sec
+		= gensec_security_by_oid_list(gensec_security, 
+					      out_mem_ctx, 
+					      mechType,
+					      GENSEC_OID_SPNEGO);
+
+	ok = spnego_write_mech_types(spnego_state,
+				     mechType,
+				     &spnego_state->mech_types);
+	if (!ok) {
+		DEBUG(1, ("SPNEGO: Failed to write mechTypes\n"));
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (spnego_state->state_position == SPNEGO_SERVER_START) {
+		uint32_t j;
+		for (j=0; mechType && mechType[j]; j++) {
+			for (i=0; all_sec && all_sec[i].op; i++) {
+				if (strcmp(mechType[j], all_sec[i].oid) != 0) {
+					continue;
+				}
+
+				nt_status = gensec_subcontext_start(spnego_state,
+								    gensec_security,
+								    &spnego_state->sub_sec_security);
+				if (!NT_STATUS_IS_OK(nt_status)) {
+					return nt_status;
+				}
+				/* select the sub context */
+				nt_status = gensec_start_mech_by_ops(spnego_state->sub_sec_security,
+								     all_sec[i].op);
+				if (!NT_STATUS_IS_OK(nt_status)) {
+					talloc_free(spnego_state->sub_sec_security);
+					spnego_state->sub_sec_security = NULL;
+					break;
+				}
+
+				if (j > 0) {
+					/* no optimistic token */
+					spnego_state->neg_oid = all_sec[i].oid;
+					*unwrapped_out = data_blob_null;
+					nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
+					break;
+				}
+
+				nt_status = gensec_update(spnego_state->sub_sec_security,
+							  out_mem_ctx, 
+							  ev,
+							  unwrapped_in,
+							  unwrapped_out);
+				if (NT_STATUS_EQUAL(nt_status, NT_STATUS_INVALID_PARAMETER) || 
+				    NT_STATUS_EQUAL(nt_status, NT_STATUS_CANT_ACCESS_DOMAIN_INFO)) {
+					/* Pretend we never started it (lets the first run find some incompatible demand) */
+					
+					DEBUG(1, ("SPNEGO(%s) NEG_TOKEN_INIT failed to parse contents: %s\n", 
+						  spnego_state->sub_sec_security->ops->name, nt_errstr(nt_status)));
+					talloc_free(spnego_state->sub_sec_security);
+					spnego_state->sub_sec_security = NULL;
+					break;
+				}
+
+				spnego_state->neg_oid = all_sec[i].oid;
+				break;
+			}
+			if (spnego_state->sub_sec_security) {
+				break;
+			}
+		}
+
+		if (!spnego_state->sub_sec_security) {
+			DEBUG(1, ("SPNEGO: Could not find a suitable mechtype in NEG_TOKEN_INIT\n"));
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+	}
+	
+	/* Having tried any optimistic token from the client (if we
+	 * were the server), if we didn't get anywhere, walk our list
+	 * in our preference order */
+	
+	if (!spnego_state->sub_sec_security) {
+		for (i=0; all_sec && all_sec[i].op; i++) {
+			nt_status = gensec_subcontext_start(spnego_state,
+							    gensec_security,
+							    &spnego_state->sub_sec_security);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				return nt_status;
+			}
+			/* select the sub context */
+			nt_status = gensec_start_mech_by_ops(spnego_state->sub_sec_security,
+							     all_sec[i].op);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				talloc_free(spnego_state->sub_sec_security);
+				spnego_state->sub_sec_security = NULL;
+				continue;
+			}
+			
+			spnego_state->neg_oid = all_sec[i].oid;
+
+			/* only get the helping start blob for the first OID */
+			nt_status = gensec_update(spnego_state->sub_sec_security,
+						  out_mem_ctx, 
+						  ev,
+						  null_data_blob, 
+						  unwrapped_out);
+
+			/* it is likely that a NULL input token will
+			 * not be liked by most server mechs, but if
+			 * we are in the client, we want the first
+			 * update packet to be able to abort the use
+			 * of this mech */
+			if (spnego_state->state_position != SPNEGO_SERVER_START) {
+				if (NT_STATUS_EQUAL(nt_status, NT_STATUS_INVALID_PARAMETER) || 
+				    NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_LOGON_SERVERS) ||
+				    NT_STATUS_EQUAL(nt_status, NT_STATUS_TIME_DIFFERENCE_AT_DC) ||
+				    NT_STATUS_EQUAL(nt_status, NT_STATUS_CANT_ACCESS_DOMAIN_INFO)) {
+					/* Pretend we never started it (lets the first run find some incompatible demand) */
+					
+					DEBUG(3, ("SPNEGO(%s) NEG_TOKEN_INIT failed: %s\n",
+						  spnego_state->sub_sec_security->ops->name, nt_errstr(nt_status)));
+					talloc_free(spnego_state->sub_sec_security);
+					spnego_state->sub_sec_security = NULL;
+					continue;
+				}
+			}
+
+			break;
+		}
+	}
+
+	if (spnego_state->sub_sec_security) {
+		/* it is likely that a NULL input token will
+		 * not be liked by most server mechs, but this
+		 * does the right thing in the CIFS client.
+		 * just push us along the merry-go-round
+		 * again, and hope for better luck next
+		 * time */
+		
+		if (NT_STATUS_EQUAL(nt_status, NT_STATUS_INVALID_PARAMETER)) {
+			*unwrapped_out = data_blob(NULL, 0);
+			nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
+		}
+		
+		if (!NT_STATUS_EQUAL(nt_status, NT_STATUS_INVALID_PARAMETER) 
+		    && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED) 
+		    && !NT_STATUS_IS_OK(nt_status)) {
+			DEBUG(1, ("SPNEGO(%s) NEG_TOKEN_INIT failed: %s\n", 
+				  spnego_state->sub_sec_security->ops->name, nt_errstr(nt_status)));
+			talloc_free(spnego_state->sub_sec_security);
+			spnego_state->sub_sec_security = NULL;
+			
+			/* We started the mech correctly, and the
+			 * input from the other side was valid.
+			 * Return the error (say bad password, invalid
+			 * ticket) */
+			return nt_status;
+		}
+	
+		
+		return nt_status; /* OK, INVALID_PARAMETER ore MORE PROCESSING */
+	}
+
+	DEBUG(1, ("SPNEGO: Could not find a suitable mechtype in NEG_TOKEN_INIT\n"));
+	/* we could re-negotiate here, but it would only work
+	 * if the client or server lied about what it could
+	 * support the first time.  Lets keep this code to
+	 * reality */
+
+	return nt_status;
+}
+
+/** create a negTokenInit 
+ *
+ * This is the same packet, no matter if the client or server sends it first, but it is always the first packet
+*/
+static NTSTATUS gensec_spnego_create_negTokenInit(struct gensec_security *gensec_security, 
+						  struct spnego_state *spnego_state,
+						  TALLOC_CTX *out_mem_ctx, 
+						  struct tevent_context *ev,
+						  const DATA_BLOB in, DATA_BLOB *out) 
+{
+	int i;
+	NTSTATUS nt_status = NT_STATUS_INVALID_PARAMETER;
+	DATA_BLOB null_data_blob = data_blob(NULL,0);
+	const char **mechTypes = NULL;
+	DATA_BLOB unwrapped_out = data_blob(NULL, 0);
+	const struct gensec_security_ops_wrapper *all_sec;
+
+	mechTypes = gensec_security_oids(gensec_security, 
+					 out_mem_ctx, GENSEC_OID_SPNEGO);
+
+	all_sec	= gensec_security_by_oid_list(gensec_security, 
+					      out_mem_ctx, 
+					      mechTypes,
+					      GENSEC_OID_SPNEGO);
+	for (i=0; all_sec && all_sec[i].op; i++) {
+		struct spnego_data spnego_out;
+		const char **send_mech_types;
+		bool ok;
+
+		nt_status = gensec_subcontext_start(spnego_state,
+						    gensec_security,
+						    &spnego_state->sub_sec_security);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			return nt_status;
+		}
+		/* select the sub context */
+		nt_status = gensec_start_mech_by_ops(spnego_state->sub_sec_security,
+						     all_sec[i].op);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			talloc_free(spnego_state->sub_sec_security);
+			spnego_state->sub_sec_security = NULL;
+			continue;
+		}
+
+		/* In the client, try and produce the first (optimistic) packet */
+		if (spnego_state->state_position == SPNEGO_CLIENT_START) {
+			nt_status = gensec_update(spnego_state->sub_sec_security,
+						  out_mem_ctx, 
+						  ev,
+						  null_data_blob,
+						  &unwrapped_out);
+			
+			if (!NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED) 
+			    && !NT_STATUS_IS_OK(nt_status)) {
+				DEBUG(1, ("SPNEGO(%s) creating NEG_TOKEN_INIT failed: %s\n", 
+					  spnego_state->sub_sec_security->ops->name, nt_errstr(nt_status)));
+				talloc_free(spnego_state->sub_sec_security);
+				spnego_state->sub_sec_security = NULL;
+				/* Pretend we never started it (lets the first run find some incompatible demand) */
+				
+				continue;
+			}
+		}
+
+		spnego_out.type = SPNEGO_NEG_TOKEN_INIT;
+
+		send_mech_types = gensec_security_oids_from_ops_wrapped(out_mem_ctx,
+									&all_sec[i]);
+
+		ok = spnego_write_mech_types(spnego_state,
+					     send_mech_types,
+					     &spnego_state->mech_types);
+		if (!ok) {
+			DEBUG(1, ("SPNEGO: Failed to write mechTypes\n"));
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		/* List the remaining mechs as options */
+		spnego_out.negTokenInit.mechTypes = send_mech_types;
+		spnego_out.negTokenInit.reqFlags = null_data_blob;
+		spnego_out.negTokenInit.reqFlagsPadding = 0;
+		
+		if (spnego_state->state_position == SPNEGO_SERVER_START) {
+			spnego_out.negTokenInit.mechListMIC
+				= data_blob_string_const(ADS_IGNORE_PRINCIPAL);
+		} else {
+			spnego_out.negTokenInit.mechListMIC = null_data_blob;
+		}
+
+		spnego_out.negTokenInit.mechToken = unwrapped_out;
+		
+		if (spnego_write_data(out_mem_ctx, out, &spnego_out) == -1) {
+			DEBUG(1, ("Failed to write NEG_TOKEN_INIT\n"));
+				return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		/* set next state */
+		spnego_state->neg_oid = all_sec[i].oid;
+		
+		if (NT_STATUS_IS_OK(nt_status)) {
+			spnego_state->no_response_expected = true;
+		}
+
+		return NT_STATUS_MORE_PROCESSING_REQUIRED;
+	} 
+	talloc_free(spnego_state->sub_sec_security);
+	spnego_state->sub_sec_security = NULL;
+
+	DEBUG(1, ("Failed to setup SPNEGO negTokenInit request: %s\n", nt_errstr(nt_status)));
+	return NT_STATUS_INVALID_PARAMETER;
+}
+
+
+/** create a server negTokenTarg 
+ *
+ * This is the case, where the client is the first one who sends data
+*/
+
+static NTSTATUS gensec_spnego_server_negTokenTarg(struct gensec_security *gensec_security, 
+						  struct spnego_state *spnego_state,
+						  TALLOC_CTX *out_mem_ctx, 
+						  NTSTATUS nt_status,
+						  const DATA_BLOB unwrapped_out,
+						  DATA_BLOB mech_list_mic,
+						  DATA_BLOB *out)
+{
+	struct spnego_data spnego_out;
+	DATA_BLOB null_data_blob = data_blob(NULL, 0);
+
+	/* compose reply */
+	spnego_out.type = SPNEGO_NEG_TOKEN_TARG;
+	spnego_out.negTokenTarg.responseToken = unwrapped_out;
+	spnego_out.negTokenTarg.mechListMIC = null_data_blob;
+	spnego_out.negTokenTarg.supportedMech = NULL;
+
+	if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {	
+		spnego_out.negTokenTarg.supportedMech = spnego_state->neg_oid;
+		spnego_out.negTokenTarg.negResult = SPNEGO_ACCEPT_INCOMPLETE;
+		spnego_state->state_position = SPNEGO_SERVER_TARG;
+	} else if (NT_STATUS_IS_OK(nt_status)) {
+		if (unwrapped_out.data) {
+			spnego_out.negTokenTarg.supportedMech = spnego_state->neg_oid;
+		}
+		spnego_out.negTokenTarg.negResult = SPNEGO_ACCEPT_COMPLETED;
+		spnego_out.negTokenTarg.mechListMIC = mech_list_mic;
+		spnego_state->state_position = SPNEGO_DONE;
+	} else {
+		spnego_out.negTokenTarg.negResult = SPNEGO_REJECT;
+		DEBUG(2, ("SPNEGO login failed: %s\n", nt_errstr(nt_status)));
+		spnego_state->state_position = SPNEGO_DONE;
+	}
+
+	if (spnego_write_data(out_mem_ctx, out, &spnego_out) == -1) {
+		DEBUG(1, ("Failed to write SPNEGO reply to NEG_TOKEN_TARG\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	spnego_state->expected_packet = SPNEGO_NEG_TOKEN_TARG;
+
+	return nt_status;
+}
+
+
+static NTSTATUS gensec_spnego_update(struct gensec_security *gensec_security, TALLOC_CTX *out_mem_ctx, 
+				     struct tevent_context *ev,
+				     const DATA_BLOB in, DATA_BLOB *out) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	DATA_BLOB null_data_blob = data_blob(NULL, 0);
+	DATA_BLOB mech_list_mic = data_blob(NULL, 0);
+	DATA_BLOB unwrapped_out = data_blob(NULL, 0);
+	struct spnego_data spnego_out;
+	struct spnego_data spnego;
+
+	ssize_t len;
+
+	*out = data_blob(NULL, 0);
+
+	if (!out_mem_ctx) {
+		out_mem_ctx = spnego_state;
+	}
+
+	/* and switch into the state machine */
+
+	switch (spnego_state->state_position) {
+	case SPNEGO_FALLBACK:
+		return gensec_update(spnego_state->sub_sec_security, ev,
+				     out_mem_ctx, in, out);
+	case SPNEGO_SERVER_START:
+	{
+		NTSTATUS nt_status;
+		if (in.length) {
+
+			len = spnego_read_data(gensec_security, in, &spnego);
+			if (len == -1) {
+				return gensec_spnego_server_try_fallback(gensec_security, spnego_state,
+									 out_mem_ctx, ev, in, out);
+			}
+			/* client sent NegTargetInit, we send NegTokenTarg */
+
+			/* OK, so it's real SPNEGO, check the packet's the one we expect */
+			if (spnego.type != spnego_state->expected_packet) {
+				DEBUG(1, ("Invalid SPNEGO request: %d, expected %d\n", spnego.type, 
+					  spnego_state->expected_packet));
+				dump_data(1, in.data, in.length);
+				spnego_free_data(&spnego);
+				return NT_STATUS_INVALID_PARAMETER;
+			}
+			
+			nt_status = gensec_spnego_parse_negTokenInit(gensec_security,
+								     spnego_state,
+								     out_mem_ctx, 
+								     ev,
+								     spnego.negTokenInit.mechTypes,
+								     spnego.negTokenInit.mechToken, 
+								     &unwrapped_out);
+			
+			nt_status = gensec_spnego_server_negTokenTarg(gensec_security,
+								      spnego_state,
+								      out_mem_ctx,
+								      nt_status,
+								      unwrapped_out,
+								      null_data_blob,
+								      out);
+			
+			spnego_free_data(&spnego);
+			
+			return nt_status;
+		} else {
+			nt_status = gensec_spnego_create_negTokenInit(gensec_security, spnego_state, 
+								      out_mem_ctx, ev, in, out);
+			spnego_state->state_position = SPNEGO_SERVER_START;
+			spnego_state->expected_packet = SPNEGO_NEG_TOKEN_INIT;
+			return nt_status;
+		}
+	}
+	
+	case SPNEGO_CLIENT_START:
+	{
+		/* The server offers a list of mechanisms */
+		
+		const char *my_mechs[] = {NULL, NULL};
+		NTSTATUS nt_status = NT_STATUS_INVALID_PARAMETER;
+
+		if (!in.length) {
+			/* client to produce negTokenInit */
+			nt_status = gensec_spnego_create_negTokenInit(gensec_security, spnego_state, 
+								      out_mem_ctx, ev, in, out);
+			spnego_state->state_position = SPNEGO_CLIENT_TARG;
+			spnego_state->expected_packet = SPNEGO_NEG_TOKEN_TARG;
+			return nt_status;
+		}
+		
+		len = spnego_read_data(gensec_security, in, &spnego);
+		
+		if (len == -1) {
+			DEBUG(1, ("Invalid SPNEGO request:\n"));
+			dump_data(1, in.data, in.length);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		/* OK, so it's real SPNEGO, check the packet's the one we expect */
+		if (spnego.type != spnego_state->expected_packet) {
+			DEBUG(1, ("Invalid SPNEGO request: %d, expected %d\n", spnego.type, 
+				  spnego_state->expected_packet));
+			dump_data(1, in.data, in.length);
+			spnego_free_data(&spnego);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		if (spnego.negTokenInit.targetPrincipal
+		    && strcmp(spnego.negTokenInit.targetPrincipal, ADS_IGNORE_PRINCIPAL) != 0) {
+			DEBUG(5, ("Server claims it's principal name is %s\n", spnego.negTokenInit.targetPrincipal));
+			if (lpcfg_client_use_spnego_principal(gensec_security->settings->lp_ctx)) {
+				gensec_set_target_principal(gensec_security, spnego.negTokenInit.targetPrincipal);
+			}
+		}
+
+		nt_status = gensec_spnego_parse_negTokenInit(gensec_security,
+							     spnego_state,
+							     out_mem_ctx, 
+							     ev,
+							     spnego.negTokenInit.mechTypes,
+							     spnego.negTokenInit.mechToken, 
+							     &unwrapped_out);
+
+		if (!NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED) && !NT_STATUS_IS_OK(nt_status)) {
+			spnego_free_data(&spnego);
+			return nt_status;
+		}
+
+		my_mechs[0] = spnego_state->neg_oid;
+		/* compose reply */
+		spnego_out.type = SPNEGO_NEG_TOKEN_INIT;
+		spnego_out.negTokenInit.mechTypes = my_mechs;
+		spnego_out.negTokenInit.reqFlags = null_data_blob;
+		spnego_out.negTokenInit.reqFlagsPadding = 0;
+		spnego_out.negTokenInit.mechListMIC = null_data_blob;
+		spnego_out.negTokenInit.mechToken = unwrapped_out;
+		
+		if (spnego_write_data(out_mem_ctx, out, &spnego_out) == -1) {
+			DEBUG(1, ("Failed to write SPNEGO reply to NEG_TOKEN_INIT\n"));
+				return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		/* set next state */
+		spnego_state->expected_packet = SPNEGO_NEG_TOKEN_TARG;
+		spnego_state->state_position = SPNEGO_CLIENT_TARG;
+
+		if (NT_STATUS_IS_OK(nt_status)) {
+			spnego_state->no_response_expected = true;
+		}
+		
+		spnego_free_data(&spnego);
+		return NT_STATUS_MORE_PROCESSING_REQUIRED;
+	}
+	case SPNEGO_SERVER_TARG:
+	{
+		NTSTATUS nt_status;
+		bool new_spnego = false;
+
+		if (!in.length) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		len = spnego_read_data(gensec_security, in, &spnego);
+		
+		if (len == -1) {
+			DEBUG(1, ("Invalid SPNEGO request:\n"));
+			dump_data(1, in.data, in.length);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		/* OK, so it's real SPNEGO, check the packet's the one we expect */
+		if (spnego.type != spnego_state->expected_packet) {
+			DEBUG(1, ("Invalid SPNEGO request: %d, expected %d\n", spnego.type, 
+				  spnego_state->expected_packet));
+			dump_data(1, in.data, in.length);
+			spnego_free_data(&spnego);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		if (!spnego_state->sub_sec_security) {
+			DEBUG(1, ("SPNEGO: Did not setup a mech in NEG_TOKEN_INIT\n"));
+			spnego_free_data(&spnego);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		nt_status = gensec_update(spnego_state->sub_sec_security,
+					  out_mem_ctx, ev,
+					  spnego.negTokenTarg.responseToken,
+					  &unwrapped_out);
+		if (NT_STATUS_IS_OK(nt_status) && spnego.negTokenTarg.mechListMIC.length > 0) {
+			new_spnego = true;
+			nt_status = gensec_check_packet(spnego_state->sub_sec_security,
+							spnego_state->mech_types.data,
+							spnego_state->mech_types.length,
+							spnego_state->mech_types.data,
+							spnego_state->mech_types.length,
+							&spnego.negTokenTarg.mechListMIC);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				DEBUG(2,("GENSEC SPNEGO: failed to verify mechListMIC: %s\n",
+					nt_errstr(nt_status)));
+			}
+		}
+		if (NT_STATUS_IS_OK(nt_status) && new_spnego) {
+			nt_status = gensec_sign_packet(spnego_state->sub_sec_security,
+						       out_mem_ctx,
+						       spnego_state->mech_types.data,
+						       spnego_state->mech_types.length,
+						       spnego_state->mech_types.data,
+						       spnego_state->mech_types.length,
+						       &mech_list_mic);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				DEBUG(2,("GENSEC SPNEGO: failed to sign mechListMIC: %s\n",
+					nt_errstr(nt_status)));
+			}
+		}
+
+		nt_status = gensec_spnego_server_negTokenTarg(gensec_security,
+							      spnego_state,
+							      out_mem_ctx, 
+							      nt_status,
+							      unwrapped_out,
+							      mech_list_mic,
+							      out);
+		
+		spnego_free_data(&spnego);
+		
+		return nt_status;
+	}
+	case SPNEGO_CLIENT_TARG:
+	{
+		NTSTATUS nt_status;
+		if (!in.length) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		len = spnego_read_data(gensec_security, in, &spnego);
+		
+		if (len == -1) {
+			DEBUG(1, ("Invalid SPNEGO request:\n"));
+			dump_data(1, in.data, in.length);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		/* OK, so it's real SPNEGO, check the packet's the one we expect */
+		if (spnego.type != spnego_state->expected_packet) {
+			DEBUG(1, ("Invalid SPNEGO request: %d, expected %d\n", spnego.type, 
+				  spnego_state->expected_packet));
+			dump_data(1, in.data, in.length);
+			spnego_free_data(&spnego);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+	
+		if (spnego.negTokenTarg.negResult == SPNEGO_REJECT) {
+			spnego_free_data(&spnego);
+			return NT_STATUS_ACCESS_DENIED;
+		}
+
+		/* Server didn't like our choice of mech, and chose something else */
+		if ((spnego.negTokenTarg.negResult == SPNEGO_ACCEPT_INCOMPLETE) &&
+		    spnego.negTokenTarg.supportedMech &&
+		    strcmp(spnego.negTokenTarg.supportedMech, spnego_state->neg_oid) != 0) {
+			DEBUG(3,("GENSEC SPNEGO: client preferred mech (%s) not accepted, server wants: %s\n",
+				 gensec_get_name_by_oid(gensec_security, spnego.negTokenTarg.supportedMech), 
+				 gensec_get_name_by_oid(gensec_security, spnego_state->neg_oid)));
+			
+			talloc_free(spnego_state->sub_sec_security);
+			nt_status = gensec_subcontext_start(spnego_state,
+							    gensec_security,
+							    &spnego_state->sub_sec_security);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				spnego_free_data(&spnego);
+				return nt_status;
+			}
+			/* select the sub context */
+			nt_status = gensec_start_mech_by_oid(spnego_state->sub_sec_security,
+							     spnego.negTokenTarg.supportedMech);
+			if (!NT_STATUS_IS_OK(nt_status)) {
+				spnego_free_data(&spnego);
+				return nt_status;
+			}
+
+			nt_status = gensec_update(spnego_state->sub_sec_security,
+						  out_mem_ctx, ev,
+						  spnego.negTokenTarg.responseToken,
+						  &unwrapped_out);
+			spnego_state->neg_oid = talloc_strdup(spnego_state, spnego.negTokenTarg.supportedMech);
+		} else if (spnego_state->no_response_expected) {
+			if (spnego.negTokenTarg.negResult != SPNEGO_ACCEPT_COMPLETED) {
+				DEBUG(3,("GENSEC SPNEGO: client GENSEC accepted, but server rejected (bad password?)\n"));
+				nt_status = NT_STATUS_INVALID_PARAMETER;
+			} else if (spnego.negTokenTarg.responseToken.length) {
+				DEBUG(2,("GENSEC SPNEGO: client GENSEC accepted, but server continued negotiation!\n"));
+				nt_status = NT_STATUS_INVALID_PARAMETER;
+			} else {
+				nt_status = NT_STATUS_OK;
+			}
+			if (NT_STATUS_IS_OK(nt_status) && spnego.negTokenTarg.mechListMIC.length > 0) {
+				nt_status = gensec_check_packet(spnego_state->sub_sec_security,
+								spnego_state->mech_types.data,
+								spnego_state->mech_types.length,
+								spnego_state->mech_types.data,
+								spnego_state->mech_types.length,
+								&spnego.negTokenTarg.mechListMIC);
+				if (!NT_STATUS_IS_OK(nt_status)) {
+					DEBUG(2,("GENSEC SPNEGO: failed to verify mechListMIC: %s\n",
+						nt_errstr(nt_status)));
+				}
+			}
+		} else {
+			bool new_spnego = false;
+
+			nt_status = gensec_update(spnego_state->sub_sec_security,
+						  out_mem_ctx, ev,
+						  spnego.negTokenTarg.responseToken, 
+						  &unwrapped_out);
+
+			if (NT_STATUS_IS_OK(nt_status)
+			    && spnego.negTokenTarg.negResult != SPNEGO_ACCEPT_COMPLETED) {
+				new_spnego = gensec_have_feature(spnego_state->sub_sec_security,
+								 GENSEC_FEATURE_NEW_SPNEGO);
+			}
+			if (NT_STATUS_IS_OK(nt_status) && new_spnego) {
+				nt_status = gensec_sign_packet(spnego_state->sub_sec_security,
+							       out_mem_ctx,
+							       spnego_state->mech_types.data,
+							       spnego_state->mech_types.length,
+							       spnego_state->mech_types.data,
+							       spnego_state->mech_types.length,
+							       &mech_list_mic);
+				if (!NT_STATUS_IS_OK(nt_status)) {
+					DEBUG(2,("GENSEC SPNEGO: failed to sign mechListMIC: %s\n",
+						nt_errstr(nt_status)));
+				}
+			}
+			if (NT_STATUS_IS_OK(nt_status)) {
+				spnego_state->no_response_expected = true;
+			}
+		} 
+		
+		spnego_free_data(&spnego);
+
+		if (!NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)
+			&& !NT_STATUS_IS_OK(nt_status)) {
+			DEBUG(1, ("SPNEGO(%s) login failed: %s\n", 
+				  spnego_state->sub_sec_security->ops->name, 
+				  nt_errstr(nt_status)));
+			return nt_status;
+		}
+
+		if (unwrapped_out.length || mech_list_mic.length) {
+			/* compose reply */
+			spnego_out.type = SPNEGO_NEG_TOKEN_TARG;
+			spnego_out.negTokenTarg.negResult = SPNEGO_NONE_RESULT;
+			spnego_out.negTokenTarg.supportedMech = NULL;
+			spnego_out.negTokenTarg.responseToken = unwrapped_out;
+			spnego_out.negTokenTarg.mechListMIC = mech_list_mic;
+			
+			if (spnego_write_data(out_mem_ctx, out, &spnego_out) == -1) {
+				DEBUG(1, ("Failed to write SPNEGO reply to NEG_TOKEN_TARG\n"));
+				return NT_STATUS_INVALID_PARAMETER;
+			}
+		
+			spnego_state->state_position = SPNEGO_CLIENT_TARG;
+			nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
+		} else {
+
+			/* all done - server has accepted, and we agree */
+			*out = null_data_blob;
+
+			if (spnego.negTokenTarg.negResult != SPNEGO_ACCEPT_COMPLETED) {
+				/* unless of course it did not accept */
+				DEBUG(1,("gensec_update ok but not accepted\n"));
+				nt_status = NT_STATUS_INVALID_PARAMETER;
+			}
+		
+			spnego_state->state_position = SPNEGO_DONE;
+		}
+
+		return nt_status;
+	}
+	case SPNEGO_DONE:
+		/* We should not be called after we are 'done' */
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	return NT_STATUS_INVALID_PARAMETER;
+}
+
+static NTSTATUS gensec_spnego_update_in(struct gensec_security *gensec_security,
+					const DATA_BLOB in, DATA_BLOB *full_in)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	size_t expected;
+	NTSTATUS status;
+	bool ok;
+
+	*full_in = data_blob_null;
+
+	if (spnego_state->in_needed == 0) {
+		size_t size = 0;
+
+		/*
+		 * try to work out the size of the full
+		 * input token, it might be fragmented
+		 */
+		status = asn1_peek_full_tag(in,  ASN1_APPLICATION(0), &size);
+		if (!NT_STATUS_IS_OK(status) &&
+		    !NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
+			status = asn1_peek_full_tag(in, ASN1_CONTEXT(1), &size);
+		}
+
+		if (NT_STATUS_IS_OK(status) ||
+		    NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
+			spnego_state->in_needed = size;
+		} else {
+			/*
+			 * If it is not an asn1 message
+			 * just call the next layer.
+			 */
+			spnego_state->in_needed = in.length;
+		}
+	}
+
+	if (spnego_state->in_needed > UINT16_MAX) {
+		/*
+		 * limit the incoming message to 0xFFFF
+		 * to avoid DoS attacks.
+		 */
+		return NT_STATUS_INVALID_BUFFER_SIZE;
+	}
+
+	if ((spnego_state->in_needed > 0) && (in.length == 0)) {
+		/*
+		 * If we reach this, we know we got at least
+		 * part of an asn1 message, getting 0 means
+		 * the remote peer wants us to spin.
+		 */
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	expected = spnego_state->in_needed - spnego_state->in_frag.length;
+	if (in.length > expected) {
+		/*
+		 * we got more than expected
+		 */
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (in.length == spnego_state->in_needed) {
+		/*
+		 * if the in.length contains the full blob
+		 * we are done.
+		 *
+		 * Note: this implies spnego_state->in_frag.length == 0,
+		 *       but we do not need to check this explicitly
+		 *       because we already know that we did not get
+		 *       more than expected.
+		 */
+		*full_in = in;
+		return NT_STATUS_OK;
+	}
+
+	ok = data_blob_append(spnego_state, &spnego_state->in_frag,
+			      in.data, in.length);
+	if (!ok) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (spnego_state->in_needed > spnego_state->in_frag.length) {
+		return NT_STATUS_MORE_PROCESSING_REQUIRED;
+	}
+
+	*full_in = spnego_state->in_frag;
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS gensec_spnego_update_out(struct gensec_security *gensec_security,
+					 TALLOC_CTX *out_mem_ctx,
+					 DATA_BLOB *_out)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	DATA_BLOB out = data_blob_null;
+
+	*_out = data_blob_null;
+
+	if (spnego_state->out_frag.length == 0) {
+		return spnego_state->out_status;
+	}
+
+	/*
+	 * There is still more data to be delivered
+	 * to the remote peer.
+	 */
+
+	if (spnego_state->out_frag.length <= spnego_state->out_max_length) {
+		/*
+		 * Fast path, we can deliver everything
+		 */
+
+		*_out = spnego_state->out_frag;
+		talloc_steal(out_mem_ctx, _out->data);
+		spnego_state->out_frag = data_blob_null;
+		return spnego_state->out_status;
+	}
+
+	out = spnego_state->out_frag;
+
+	/*
+	 * copy the remaining bytes
+	 */
+	spnego_state->out_frag = data_blob_talloc(spnego_state,
+					out.data + spnego_state->out_max_length,
+					out.length - spnego_state->out_max_length);
+	if (spnego_state->out_frag.data == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	/*
+	 * truncate the buffer
+	 */
+	data_blob_realloc(spnego_state, &out, spnego_state->out_max_length);
+
+	talloc_steal(out_mem_ctx, out.data);
+	*_out = out;
+	return NT_STATUS_MORE_PROCESSING_REQUIRED;
+}
+
+static NTSTATUS gensec_spnego_update_wrapper(struct gensec_security *gensec_security,
+					     TALLOC_CTX *out_mem_ctx,
+					     struct tevent_context *ev,
+					     const DATA_BLOB in, DATA_BLOB *out)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	DATA_BLOB full_in = data_blob_null;
+	NTSTATUS status;
+
+	*out = data_blob_null;
+
+	if (spnego_state->out_frag.length > 0) {
+		if (in.length > 0) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		return gensec_spnego_update_out(gensec_security,
+						out_mem_ctx,
+						out);
+	}
+
+	status = gensec_spnego_update_in(gensec_security,
+					 in, &full_in);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+
+	status = gensec_spnego_update(gensec_security,
+				      spnego_state, ev,
+				      full_in,
+				      &spnego_state->out_frag);
+	data_blob_free(&spnego_state->in_frag);
+	spnego_state->in_needed = 0;
+	if (!NT_STATUS_IS_OK(status) &&
+	    !NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		return status;
+	}
+
+	spnego_state->out_status = status;
+
+	return gensec_spnego_update_out(gensec_security,
+					out_mem_ctx,
+					out);
+}
+
+static void gensec_spnego_want_feature(struct gensec_security *gensec_security,
+				       uint32_t feature)
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+
+	if (!spnego_state || !spnego_state->sub_sec_security) {
+		gensec_security->want_features |= feature;
+		return;
+	}
+
+	gensec_want_feature(spnego_state->sub_sec_security,
+			    feature);
+}
+
+static bool gensec_spnego_have_feature(struct gensec_security *gensec_security,
+				       uint32_t feature) 
+{
+	struct spnego_state *spnego_state = (struct spnego_state *)gensec_security->private_data;
+	if (!spnego_state->sub_sec_security) {
+		return false;
+	}
+	
+	return gensec_have_feature(spnego_state->sub_sec_security, 
+				   feature);
+}
+
+static const char *gensec_spnego_oids[] = { 
+	GENSEC_OID_SPNEGO,
+	NULL 
+};
+
+static const struct gensec_security_ops gensec_spnego_security_ops = {
+	.name		  = "spnego",
+	.sasl_name	  = "GSS-SPNEGO",
+	.auth_type	  = DCERPC_AUTH_TYPE_SPNEGO,
+	.oid              = gensec_spnego_oids,
+	.client_start     = gensec_spnego_client_start,
+	.server_start     = gensec_spnego_server_start,
+	.update 	  = gensec_spnego_update_wrapper,
+	.seal_packet	  = gensec_spnego_seal_packet,
+	.sign_packet	  = gensec_spnego_sign_packet,
+	.sig_size	  = gensec_spnego_sig_size,
+	.max_wrapped_size = gensec_spnego_max_wrapped_size,
+	.max_input_size	  = gensec_spnego_max_input_size,
+	.check_packet	  = gensec_spnego_check_packet,
+	.unseal_packet	  = gensec_spnego_unseal_packet,
+	.packet_full_request = gensec_spnego_packet_full_request,
+	.wrap             = gensec_spnego_wrap,
+	.unwrap           = gensec_spnego_unwrap,
+	.wrap_packets     = gensec_spnego_wrap_packets,
+	.unwrap_packets   = gensec_spnego_unwrap_packets,
+	.session_key	  = gensec_spnego_session_key,
+	.session_info     = gensec_spnego_session_info,
+	.want_feature     = gensec_spnego_want_feature,
+	.have_feature     = gensec_spnego_have_feature,
+	.enabled          = true,
+	.priority         = GENSEC_SPNEGO
+};
+
+_PUBLIC_ NTSTATUS gensec_spnego_init(void)
+{
+	NTSTATUS ret;
+	ret = gensec_register(&gensec_spnego_security_ops);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(0,("Failed to register '%s' gensec backend!\n",
+			gensec_spnego_security_ops.name));
+		return ret;
+	}
+
+	return ret;
+}
diff --git a/auth/gensec/wscript_build b/auth/gensec/wscript_build
index 03d97e6cc9..7ca3cab003 100644
--- a/auth/gensec/wscript_build
+++ b/auth/gensec/wscript_build
@@ -9,3 +9,10 @@ bld.SAMBA_LIBRARY('gensec',
 	vnum='0.0.1'
 	)
 
+bld.SAMBA_MODULE('gensec_spnego',
+	source='spnego.c',
+	autoproto='spnego_proto.h',
+	subsystem='gensec',
+	init_function='gensec_spnego_init',
+	deps='asn1util samba-credentials SPNEGO_PARSE'
+	)