r6458: Split up NTLMSSP into a new directory, and into seperate files for the

client and server logic code.  In future, this may allow us to build
only the NTLMSSP client, and not the server, but in the short-term, it
allows me greater sainity in moving around these files.

Andrew Bartlett
(This used to be commit 2f22841c6753e3d5816c12bd463b71f74e1d8796)

1 files changed, 765 insertions, 0 deletions

diff --git a/source4/auth/ntlmssp/ntlmssp_server.c b/source4/auth/ntlmssp/ntlmssp_server.c
new file mode 100644
index 0000000000..d1e97aeb1f
--- /dev/null
+++ b/source4/auth/ntlmssp/ntlmssp_server.c
@@ -0,0 +1,765 @@
+/* 
+   Unix SMB/Netbios implementation.
+   Version 3.0
+   handle NLTMSSP, client server side parsing
+
+   Copyright (C) Andrew Tridgell      2001
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2001-2005
+   Copyright (C) Stefan Metzmacher 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 2 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, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+#include "auth/auth.h"
+#include "auth/ntlmssp/ntlmssp.h"
+#include "lib/crypto/crypto.h"
+#include "pstring.h"
+
+/**
+ * Default challenge generation code.
+ *
+ */
+   
+static const uint8_t *get_challenge(const struct ntlmssp_state *ntlmssp_state)
+{
+	uint8_t *chal = talloc_size(ntlmssp_state, 8);
+	generate_random_buffer(chal, 8);
+
+	return chal;
+}
+
+/**
+ * Default 'we can set the challenge to anything we like' implementation
+ *
+ */
+   
+static BOOL may_set_challenge(const struct ntlmssp_state *ntlmssp_state)
+{
+	return True;
+}
+
+/**
+ * Default 'we can set the challenge to anything we like' implementation
+ *
+ * Does not actually do anything, as the value is always in the structure anyway.
+ *
+ */
+   
+static NTSTATUS set_challenge(struct ntlmssp_state *ntlmssp_state, DATA_BLOB *challenge)
+{
+	SMB_ASSERT(challenge->length == 8);
+	return NT_STATUS_OK;
+}
+
+/**
+ * Determine correct target name flags for reply, given server role 
+ * and negotiated flags
+ * 
+ * @param ntlmssp_state NTLMSSP State
+ * @param neg_flags The flags from the packet
+ * @param chal_flags The flags to be set in the reply packet
+ * @return The 'target name' string.
+ */
+
+static const char *ntlmssp_target_name(struct ntlmssp_state *ntlmssp_state,
+				       uint32_t neg_flags, uint32_t *chal_flags) 
+{
+	if (neg_flags & NTLMSSP_REQUEST_TARGET) {
+		*chal_flags |= NTLMSSP_CHAL_TARGET_INFO;
+		*chal_flags |= NTLMSSP_REQUEST_TARGET;
+		if (ntlmssp_state->server_role == ROLE_STANDALONE) {
+			*chal_flags |= NTLMSSP_TARGET_TYPE_SERVER;
+			return ntlmssp_state->server_name;
+		} else {
+			*chal_flags |= NTLMSSP_TARGET_TYPE_DOMAIN;
+			return ntlmssp_state->get_domain();
+		};
+	} else {
+		return "";
+	}
+}
+
+/**
+ * Next state function for the Negotiate packet
+ * 
+ * @param ntlmssp_state NTLMSSP State
+ * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
+ * @param in The request, as a DATA_BLOB
+ * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
+ * @return Errors or MORE_PROCESSING_REQUIRED if a reply is sent. 
+ */
+
+NTSTATUS ntlmssp_server_negotiate(struct ntlmssp_state *ntlmssp_state,
+				  TALLOC_CTX *out_mem_ctx, 
+				  const DATA_BLOB in, DATA_BLOB *out) 
+{
+	DATA_BLOB struct_blob;
+	fstring dnsname, dnsdomname;
+	uint32_t neg_flags = 0;
+	uint32_t ntlmssp_command, chal_flags;
+	char *cliname=NULL, *domname=NULL;
+	const uint8_t *cryptkey;
+	const char *target_name;
+
+	/* parse the NTLMSSP packet */
+#if 0
+	file_save("ntlmssp_negotiate.dat", request.data, request.length);
+#endif
+
+	if (in.length) {
+		if (!msrpc_parse(ntlmssp_state, 
+				 &in, "CddAA",
+				 "NTLMSSP",
+				 &ntlmssp_command,
+				 &neg_flags,
+				 &cliname,
+				 &domname)) {
+			DEBUG(1, ("ntlmssp_server_negotiate: failed to parse NTLMSSP:\n"));
+			dump_data(2, in.data, in.length);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		debug_ntlmssp_flags(neg_flags);
+	}
+	
+	ntlmssp_handle_neg_flags(ntlmssp_state, neg_flags, ntlmssp_state->allow_lm_key);
+
+	/* Ask our caller what challenge they would like in the packet */
+	cryptkey = ntlmssp_state->get_challenge(ntlmssp_state);
+
+	/* Check if we may set the challenge */
+	if (!ntlmssp_state->may_set_challenge(ntlmssp_state)) {
+		ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_NTLM2;
+	}
+
+	/* The flags we send back are not just the negotiated flags,
+	 * they are also 'what is in this packet'.  Therfore, we
+	 * operate on 'chal_flags' from here on 
+	 */
+
+	chal_flags = ntlmssp_state->neg_flags;
+
+	/* get the right name to fill in as 'target' */
+	target_name = ntlmssp_target_name(ntlmssp_state, 
+					  neg_flags, &chal_flags); 
+	if (target_name == NULL) 
+		return NT_STATUS_INVALID_PARAMETER;
+
+	ntlmssp_state->chal = data_blob_talloc(ntlmssp_state, cryptkey, 8);
+	ntlmssp_state->internal_chal = data_blob_talloc(ntlmssp_state, cryptkey, 8);
+
+	/* This should be a 'netbios domain -> DNS domain' mapping */
+	dnsdomname[0] = '\0';
+	get_mydomname(dnsdomname);
+	strlower_m(dnsdomname);
+	
+	dnsname[0] = '\0';
+	get_myfullname(dnsname);
+	
+	/* This creates the 'blob' of names that appears at the end of the packet */
+	if (chal_flags & NTLMSSP_CHAL_TARGET_INFO) 
+	{
+		const char *target_name_dns = "";
+		if (chal_flags |= NTLMSSP_TARGET_TYPE_DOMAIN) {
+			target_name_dns = dnsdomname;
+		} else if (chal_flags |= NTLMSSP_TARGET_TYPE_SERVER) {
+			target_name_dns = dnsname;
+		}
+
+		msrpc_gen(out_mem_ctx, 
+			  &struct_blob, "aaaaa",
+			  NTLMSSP_NAME_TYPE_DOMAIN, target_name,
+			  NTLMSSP_NAME_TYPE_SERVER, ntlmssp_state->server_name,
+			  NTLMSSP_NAME_TYPE_DOMAIN_DNS, dnsdomname,
+			  NTLMSSP_NAME_TYPE_SERVER_DNS, dnsname,
+			  0, "");
+	} else {
+		struct_blob = data_blob(NULL, 0);
+	}
+
+	{
+		/* Marshel the packet in the right format, be it unicode or ASCII */
+		const char *gen_string;
+		if (ntlmssp_state->unicode) {
+			gen_string = "CdUdbddB";
+		} else {
+			gen_string = "CdAdbddB";
+		}
+		
+		msrpc_gen(out_mem_ctx, 
+			  out, gen_string,
+			  "NTLMSSP", 
+			  NTLMSSP_CHALLENGE,
+			  target_name,
+			  chal_flags,
+			  cryptkey, 8,
+			  0, 0,
+			  struct_blob.data, struct_blob.length);
+	}
+		
+	ntlmssp_state->expected_state = NTLMSSP_AUTH;
+
+	return NT_STATUS_MORE_PROCESSING_REQUIRED;
+}
+
+/**
+ * Next state function for the Authenticate packet
+ * 
+ * @param ntlmssp_state NTLMSSP State
+ * @param request The request, as a DATA_BLOB
+ * @return Errors or NT_STATUS_OK. 
+ */
+
+static NTSTATUS ntlmssp_server_preauth(struct ntlmssp_state *ntlmssp_state,
+				       const DATA_BLOB request) 
+{
+	uint32_t ntlmssp_command, auth_flags;
+	NTSTATUS nt_status;
+
+	uint8_t session_nonce_hash[16];
+
+	const char *parse_string;
+	char *domain = NULL;
+	char *user = NULL;
+	char *workstation = NULL;
+
+#if 0
+	file_save("ntlmssp_auth.dat", request.data, request.length);
+#endif
+
+	if (ntlmssp_state->unicode) {
+		parse_string = "CdBBUUUBd";
+	} else {
+		parse_string = "CdBBAAABd";
+	}
+
+	/* zero these out */
+	data_blob_free(&ntlmssp_state->lm_resp);
+	data_blob_free(&ntlmssp_state->nt_resp);
+
+	ntlmssp_state->user = NULL;
+	ntlmssp_state->domain = NULL;
+	ntlmssp_state->workstation = NULL;
+
+	/* now the NTLMSSP encoded auth hashes */
+	if (!msrpc_parse(ntlmssp_state, 
+			 &request, parse_string,
+			 "NTLMSSP", 
+			 &ntlmssp_command, 
+			 &ntlmssp_state->lm_resp,
+			 &ntlmssp_state->nt_resp,
+			 &domain, 
+			 &user, 
+			 &workstation,
+			 &ntlmssp_state->encrypted_session_key,
+			 &auth_flags)) {
+		DEBUG(10, ("ntlmssp_server_auth: failed to parse NTLMSSP (nonfatal):\n"));
+		dump_data(10, request.data, request.length);
+
+		/* zero this out */
+		data_blob_free(&ntlmssp_state->encrypted_session_key);
+		auth_flags = 0;
+		
+		/* Try again with a shorter string (Win9X truncates this packet) */
+		if (ntlmssp_state->unicode) {
+			parse_string = "CdBBUUU";
+		} else {
+			parse_string = "CdBBAAA";
+		}
+
+		/* now the NTLMSSP encoded auth hashes */
+		if (!msrpc_parse(ntlmssp_state, 
+				 &request, parse_string,
+				 "NTLMSSP", 
+				 &ntlmssp_command, 
+				 &ntlmssp_state->lm_resp,
+				 &ntlmssp_state->nt_resp,
+				 &domain, 
+				 &user, 
+				 &workstation)) {
+			DEBUG(1, ("ntlmssp_server_auth: failed to parse NTLMSSP:\n"));
+			dump_data(2, request.data, request.length);
+
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+	}
+
+	if (auth_flags)
+		ntlmssp_handle_neg_flags(ntlmssp_state, auth_flags, ntlmssp_state->allow_lm_key);
+
+	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_domain(ntlmssp_state, domain))) {
+		/* zero this out */
+		data_blob_free(&ntlmssp_state->encrypted_session_key);
+		return nt_status;
+	}
+
+	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_username(ntlmssp_state, user))) {
+		/* zero this out */
+		data_blob_free(&ntlmssp_state->encrypted_session_key);
+		return nt_status;
+	}
+
+	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_workstation(ntlmssp_state, workstation))) {
+		/* zero this out */
+		data_blob_free(&ntlmssp_state->encrypted_session_key);
+		return nt_status;
+	}
+
+	DEBUG(3,("Got user=[%s] domain=[%s] workstation=[%s] len1=%lu len2=%lu\n",
+		 ntlmssp_state->user, ntlmssp_state->domain, ntlmssp_state->workstation, (unsigned long)ntlmssp_state->lm_resp.length, (unsigned long)ntlmssp_state->nt_resp.length));
+
+#if 0
+	file_save("nthash1.dat",  &ntlmssp_state->nt_resp.data,  &ntlmssp_state->nt_resp.length);
+	file_save("lmhash1.dat",  &ntlmssp_state->lm_resp.data,  &ntlmssp_state->lm_resp.length);
+#endif
+
+	/* NTLM2 uses a 'challenge' that is made of up both the server challenge, and a 
+	   client challenge 
+	
+	   However, the NTLM2 flag may still be set for the real NTLMv2 logins, be careful.
+	*/
+	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
+		if (ntlmssp_state->nt_resp.length == 24 && ntlmssp_state->lm_resp.length == 24) {
+			struct MD5Context md5_session_nonce_ctx;
+			SMB_ASSERT(ntlmssp_state->internal_chal.data 
+				   && ntlmssp_state->internal_chal.length == 8);
+			
+			ntlmssp_state->doing_ntlm2 = True;
+
+			memcpy(ntlmssp_state->session_nonce, ntlmssp_state->internal_chal.data, 8);
+			memcpy(&ntlmssp_state->session_nonce[8], ntlmssp_state->lm_resp.data, 8);
+			
+			MD5Init(&md5_session_nonce_ctx);
+			MD5Update(&md5_session_nonce_ctx, ntlmssp_state->session_nonce, 16);
+			MD5Final(session_nonce_hash, &md5_session_nonce_ctx);
+			
+			ntlmssp_state->chal = data_blob_talloc(ntlmssp_state, 
+							       session_nonce_hash, 8);
+
+			/* LM response is no longer useful, zero it out */
+			data_blob_free(&ntlmssp_state->lm_resp);
+
+			/* We changed the effective challenge - set it */
+			if (!NT_STATUS_IS_OK(nt_status = 
+					     ntlmssp_state->set_challenge(ntlmssp_state, 
+									  &ntlmssp_state->chal))) {
+				/* zero this out */
+				data_blob_free(&ntlmssp_state->encrypted_session_key);
+				return nt_status;
+			}
+
+			/* LM Key is incompatible... */
+			ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+		}
+	}
+	return NT_STATUS_OK;
+}
+
+/**
+ * Next state function for the Authenticate packet 
+ * (after authentication - figures out the session keys etc)
+ * 
+ * @param ntlmssp_state NTLMSSP State
+ * @return Errors or NT_STATUS_OK. 
+ */
+
+static NTSTATUS ntlmssp_server_postauth(struct ntlmssp_state *ntlmssp_state,
+					DATA_BLOB *user_session_key, 
+					DATA_BLOB *lm_session_key) 
+{
+	NTSTATUS nt_status;
+	DATA_BLOB session_key = data_blob(NULL, 0);
+
+	if (user_session_key)
+		dump_data_pw("USER session key:\n", user_session_key->data, user_session_key->length);
+
+	if (lm_session_key) 
+		dump_data_pw("LM first-8:\n", lm_session_key->data, lm_session_key->length);
+
+	/* Handle the different session key derivation for NTLM2 */
+	if (ntlmssp_state->doing_ntlm2) {
+		if (user_session_key && user_session_key->data && user_session_key->length == 16) {
+			session_key = data_blob_talloc(ntlmssp_state, NULL, 16);
+			hmac_md5(user_session_key->data, ntlmssp_state->session_nonce, 
+				 sizeof(ntlmssp_state->session_nonce), session_key.data);
+			DEBUG(10,("ntlmssp_server_auth: Created NTLM2 session key.\n"));
+			dump_data_pw("NTLM2 session key:\n", session_key.data, session_key.length);
+			
+		} else {
+			DEBUG(10,("ntlmssp_server_auth: Failed to create NTLM2 session key.\n"));
+			session_key = data_blob(NULL, 0);
+		}
+	} else if ((ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) 
+		/* Ensure we can never get here on NTLMv2 */
+		&& (ntlmssp_state->nt_resp.length == 0 || ntlmssp_state->nt_resp.length == 24)) {
+
+		if (lm_session_key && lm_session_key->data && lm_session_key->length >= 8) {
+			if (ntlmssp_state->lm_resp.data && ntlmssp_state->lm_resp.length == 24) {
+				session_key = data_blob_talloc(ntlmssp_state, NULL, 16);
+				SMBsesskeygen_lm_sess_key(lm_session_key->data, ntlmssp_state->lm_resp.data, 
+							  session_key.data);
+				DEBUG(10,("ntlmssp_server_auth: Created NTLM session key.\n"));
+				dump_data_pw("LM session key:\n", session_key.data, session_key.length);
+  			} else {
+				
+				/* When there is no LM response, just use zeros */
+ 				static const uint8_t zeros[24];
+ 				session_key = data_blob_talloc(ntlmssp_state, NULL, 16);
+ 				SMBsesskeygen_lm_sess_key(zeros, zeros, 
+ 							  session_key.data);
+ 				DEBUG(10,("ntlmssp_server_auth: Created NTLM session key.\n"));
+ 				dump_data_pw("LM session key:\n", session_key.data, session_key.length);
+			}
+		} else {
+ 			/* LM Key not selected */
+ 			ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+
+			DEBUG(10,("ntlmssp_server_auth: Failed to create NTLM session key.\n"));
+			session_key = data_blob(NULL, 0);
+		}
+
+	} else if (user_session_key && user_session_key->data) {
+		session_key = *user_session_key;
+		DEBUG(10,("ntlmssp_server_auth: Using unmodified nt session key.\n"));
+		dump_data_pw("unmodified session key:\n", session_key.data, session_key.length);
+
+		/* LM Key not selected */
+		ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+
+	} else if (lm_session_key && lm_session_key->data) {
+		/* Very weird to have LM key, but no user session key, but anyway.. */
+		session_key = *lm_session_key;
+		DEBUG(10,("ntlmssp_server_auth: Using unmodified lm session key.\n"));
+		dump_data_pw("unmodified session key:\n", session_key.data, session_key.length);
+
+		/* LM Key not selected */
+		ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+
+	} else {
+		DEBUG(10,("ntlmssp_server_auth: Failed to create unmodified session key.\n"));
+		session_key = data_blob(NULL, 0);
+
+		/* LM Key not selected */
+		ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+	}
+
+	/* With KEY_EXCH, the client supplies the proposed session key, 
+	   but encrypts it with the long-term key */
+	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
+		if (!ntlmssp_state->encrypted_session_key.data 
+		    || ntlmssp_state->encrypted_session_key.length != 16) {
+			data_blob_free(&ntlmssp_state->encrypted_session_key);
+			DEBUG(1, ("Client-supplied KEY_EXCH session key was of invalid length (%u)!\n", 
+				  ntlmssp_state->encrypted_session_key.length));
+			return NT_STATUS_INVALID_PARAMETER;
+		} else if (!session_key.data || session_key.length != 16) {
+			DEBUG(5, ("server session key is invalid (len == %u), cannot do KEY_EXCH!\n", 
+				  session_key.length));
+			ntlmssp_state->session_key = session_key;
+		} else {
+			dump_data_pw("KEY_EXCH session key (enc):\n", 
+				     ntlmssp_state->encrypted_session_key.data, 
+				     ntlmssp_state->encrypted_session_key.length);
+			arcfour_crypt(ntlmssp_state->encrypted_session_key.data, 
+				      session_key.data, 
+				      ntlmssp_state->encrypted_session_key.length);
+			ntlmssp_state->session_key = data_blob_talloc(ntlmssp_state, 
+								      ntlmssp_state->encrypted_session_key.data, 
+								      ntlmssp_state->encrypted_session_key.length);
+			dump_data_pw("KEY_EXCH session key:\n", ntlmssp_state->encrypted_session_key.data, 
+				     ntlmssp_state->encrypted_session_key.length);
+		}
+	} else {
+		ntlmssp_state->session_key = session_key;
+	}
+
+ 	/* The server might need us to use a partial-strength session key */
+ 	ntlmssp_weaken_keys(ntlmssp_state);
+
+	nt_status = ntlmssp_sign_init(ntlmssp_state);
+
+	data_blob_free(&ntlmssp_state->encrypted_session_key);
+	
+	/* allow arbitarily many authentications, but watch that this will cause a 
+	   memory leak, until the ntlmssp_state is shutdown 
+	*/
+
+	if (ntlmssp_state->server_multiple_authentications) {
+		ntlmssp_state->expected_state = NTLMSSP_AUTH;
+	} else {
+		ntlmssp_state->expected_state = NTLMSSP_DONE;
+	}
+
+	return nt_status;
+}
+
+
+/**
+ * Next state function for the Authenticate packet
+ * 
+ * @param ntlmssp_state NTLMSSP State
+ * @param in The packet in from the NTLMSSP partner, as a DATA_BLOB
+ * @param out The reply, as an allocated DATA_BLOB, caller to free.
+ * @return Errors, NT_STATUS_MORE_PROCESSING_REQUIRED or NT_STATUS_OK. 
+ */
+
+NTSTATUS ntlmssp_server_auth(struct ntlmssp_state *ntlmssp_state,
+			     TALLOC_CTX *out_mem_ctx, 
+			     const DATA_BLOB in, DATA_BLOB *out) 
+{
+	DATA_BLOB user_session_key = data_blob(NULL, 0);
+	DATA_BLOB lm_session_key = data_blob(NULL, 0);
+	NTSTATUS nt_status;
+
+	/* zero the outbound NTLMSSP packet */
+	*out = data_blob_talloc(out_mem_ctx, NULL, 0);
+
+	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_server_preauth(ntlmssp_state, in))) {
+		return nt_status;
+	}
+
+	/*
+	 * Note we don't check here for NTLMv2 auth settings. If NTLMv2 auth
+	 * is required (by "ntlm auth = no" and "lm auth = no" being set in the
+	 * smb.conf file) and no NTLMv2 response was sent then the password check
+	 * will fail here. JRA.
+	 */
+
+	/* Finally, actually ask if the password is OK */
+
+	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_state->check_password(ntlmssp_state, 
+								       &user_session_key, &lm_session_key))) {
+		return nt_status;
+	}
+	
+	if (ntlmssp_state->server_use_session_keys) {
+		return ntlmssp_server_postauth(ntlmssp_state, &user_session_key, &lm_session_key);
+	} else {
+		ntlmssp_state->session_key = data_blob(NULL, 0);
+		return NT_STATUS_OK;
+	}
+}
+
+/**
+ * Create an NTLMSSP state machine
+ * 
+ * @param ntlmssp_state NTLMSSP State, allocated by this function
+ */
+
+static NTSTATUS ntlmssp_server_start(TALLOC_CTX *mem_ctx, struct ntlmssp_state **ntlmssp_state)
+{
+	*ntlmssp_state = talloc(mem_ctx, struct ntlmssp_state);
+	if (!*ntlmssp_state) {
+		DEBUG(0,("ntlmssp_server_start: talloc failed!\n"));
+		return NT_STATUS_NO_MEMORY;
+	}
+	ZERO_STRUCTP(*ntlmssp_state);
+
+	(*ntlmssp_state)->role = NTLMSSP_SERVER;
+
+	(*ntlmssp_state)->get_challenge = get_challenge;
+	(*ntlmssp_state)->set_challenge = set_challenge;
+	(*ntlmssp_state)->may_set_challenge = may_set_challenge;
+
+	(*ntlmssp_state)->workstation = NULL;
+	(*ntlmssp_state)->server_name = lp_netbios_name();
+
+	(*ntlmssp_state)->get_domain = lp_workgroup;
+	(*ntlmssp_state)->server_role = ROLE_DOMAIN_MEMBER; /* a good default */
+
+	(*ntlmssp_state)->expected_state = NTLMSSP_NEGOTIATE;
+
+	(*ntlmssp_state)->allow_lm_key = (lp_lanman_auth() 
+					  && lp_parm_bool(-1, "ntlmssp_server", "allow_lm_key", False));
+
+	(*ntlmssp_state)->server_use_session_keys = True;
+	(*ntlmssp_state)->server_multiple_authentications = False;
+	
+	(*ntlmssp_state)->ref_count = 1;
+
+	(*ntlmssp_state)->neg_flags = 
+		NTLMSSP_NEGOTIATE_NTLM;
+
+	if (lp_parm_bool(-1, "ntlmssp_server", "128bit", True)) {
+		(*ntlmssp_state)->neg_flags |= NTLMSSP_NEGOTIATE_128;		
+	}
+
+	if (lp_parm_bool(-1, "ntlmssp_server", "keyexchange", True)) {
+		(*ntlmssp_state)->neg_flags |= NTLMSSP_NEGOTIATE_KEY_EXCH;		
+	}
+
+	if (lp_parm_bool(-1, "ntlmssp_server", "ntlm2", True)) {
+		(*ntlmssp_state)->neg_flags |= NTLMSSP_NEGOTIATE_NTLM2;		
+	}
+
+	return NT_STATUS_OK;
+}
+
+/**
+ * Return the challenge as determined by the authentication subsystem 
+ * @return an 8 byte random challenge
+ */
+
+static const uint8_t *auth_ntlmssp_get_challenge(const struct ntlmssp_state *ntlmssp_state)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = ntlmssp_state->auth_context;
+	NTSTATUS status;
+	const uint8_t *chal;
+
+	status = auth_get_challenge(gensec_ntlmssp_state->auth_context, &chal);
+	if (!NT_STATUS_IS_OK(status)) {
+		return NULL;
+	}
+
+	return chal;
+}
+
+/**
+ * Some authentication methods 'fix' the challenge, so we may not be able to set it
+ *
+ * @return If the effective challenge used by the auth subsystem may be modified
+ */
+static BOOL auth_ntlmssp_may_set_challenge(const struct ntlmssp_state *ntlmssp_state)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = ntlmssp_state->auth_context;
+
+	return auth_challenge_may_be_modified(gensec_ntlmssp_state->auth_context);
+}
+
+/**
+ * NTLM2 authentication modifies the effective challenge, 
+ * @param challenge The new challenge value
+ */
+static NTSTATUS auth_ntlmssp_set_challenge(struct ntlmssp_state *ntlmssp_state, DATA_BLOB *challenge)
+{
+	NTSTATUS nt_status;
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = ntlmssp_state->auth_context;
+	struct auth_context *auth_context = gensec_ntlmssp_state->auth_context;
+	const uint8_t *chal;
+
+	if (challenge->length != 8) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	chal = challenge->data;
+
+	nt_status = auth_context_set_challenge(auth_context, chal, "NTLMSSP callback (NTLM2)");
+
+	return nt_status;
+}
+
+/**
+ * Check the password on an NTLMSSP login.  
+ *
+ * Return the session keys used on the connection.
+ */
+
+static NTSTATUS auth_ntlmssp_check_password(struct ntlmssp_state *ntlmssp_state, DATA_BLOB *user_session_key, DATA_BLOB *lm_session_key) 
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = ntlmssp_state->auth_context;
+	struct auth_usersupplied_info *user_info = NULL;
+	NTSTATUS nt_status;
+
+	nt_status = make_user_info_map(ntlmssp_state, 
+				       gensec_ntlmssp_state->ntlmssp_state->user, 
+				       gensec_ntlmssp_state->ntlmssp_state->domain, 
+				       gensec_ntlmssp_state->ntlmssp_state->workstation, 
+	                               gensec_ntlmssp_state->ntlmssp_state->lm_resp.data ? &gensec_ntlmssp_state->ntlmssp_state->lm_resp : NULL, 
+	                               gensec_ntlmssp_state->ntlmssp_state->nt_resp.data ? &gensec_ntlmssp_state->ntlmssp_state->nt_resp : NULL, 
+				       NULL, NULL, NULL, True,
+				       &user_info);
+	NT_STATUS_NOT_OK_RETURN(nt_status);
+
+	nt_status = auth_check_password(gensec_ntlmssp_state->auth_context, gensec_ntlmssp_state,
+					user_info, &gensec_ntlmssp_state->server_info);
+	talloc_free(user_info);
+	NT_STATUS_NOT_OK_RETURN(nt_status);
+
+	if (gensec_ntlmssp_state->server_info->user_session_key.length) {
+		DEBUG(10, ("Got NT session key of length %u\n", gensec_ntlmssp_state->server_info->user_session_key.length));
+		*user_session_key = data_blob_talloc(ntlmssp_state, 
+						   gensec_ntlmssp_state->server_info->user_session_key.data,
+						   gensec_ntlmssp_state->server_info->user_session_key.length);
+	}
+	if (gensec_ntlmssp_state->server_info->lm_session_key.length) {
+		DEBUG(10, ("Got LM session key of length %u\n", gensec_ntlmssp_state->server_info->lm_session_key.length));
+		*lm_session_key = data_blob_talloc(ntlmssp_state, 
+						   gensec_ntlmssp_state->server_info->lm_session_key.data,
+						   gensec_ntlmssp_state->server_info->lm_session_key.length);
+	}
+	return nt_status;
+}
+
+NTSTATUS gensec_ntlmssp_server_start(struct gensec_security *gensec_security)
+{
+	NTSTATUS nt_status;
+	struct ntlmssp_state *ntlmssp_state;
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state;
+
+	nt_status = gensec_ntlmssp_start(gensec_security);
+	NT_STATUS_NOT_OK_RETURN(nt_status);
+
+	gensec_ntlmssp_state = gensec_security->private_data;
+
+	nt_status = ntlmssp_server_start(gensec_ntlmssp_state, &gensec_ntlmssp_state->ntlmssp_state);
+	NT_STATUS_NOT_OK_RETURN(nt_status);
+
+	if (gensec_security->want_features & GENSEC_FEATURE_SIGN) {
+		gensec_ntlmssp_state->ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SIGN;
+	}
+	if (gensec_security->want_features & GENSEC_FEATURE_SEAL) {
+		gensec_ntlmssp_state->ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
+	}
+
+	nt_status = auth_context_create(gensec_ntlmssp_state, lp_auth_methods(), &gensec_ntlmssp_state->auth_context);
+	NT_STATUS_NOT_OK_RETURN(nt_status);
+
+	ntlmssp_state = gensec_ntlmssp_state->ntlmssp_state;
+	ntlmssp_state->auth_context = gensec_ntlmssp_state;
+	ntlmssp_state->get_challenge = auth_ntlmssp_get_challenge;
+	ntlmssp_state->may_set_challenge = auth_ntlmssp_may_set_challenge;
+	ntlmssp_state->set_challenge = auth_ntlmssp_set_challenge;
+	ntlmssp_state->check_password = auth_ntlmssp_check_password;
+	ntlmssp_state->server_role = lp_server_role();
+
+	return NT_STATUS_OK;
+}
+
+/** 
+ * Return the credentials of a logged on user, including session keys
+ * etc.
+ *
+ * Only valid after a successful authentication
+ *
+ * May only be called once per authentication.
+ *
+ */
+
+NTSTATUS gensec_ntlmssp_session_info(struct gensec_security *gensec_security,
+				     struct auth_session_info **session_info) 
+{
+	NTSTATUS nt_status;
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+
+	nt_status = auth_generate_session_info(gensec_ntlmssp_state, gensec_ntlmssp_state->server_info, session_info);
+	NT_STATUS_NOT_OK_RETURN(nt_status);
+
+	(*session_info)->session_key = data_blob_talloc(*session_info, 
+							gensec_ntlmssp_state->ntlmssp_state->session_key.data,
+							gensec_ntlmssp_state->ntlmssp_state->session_key.length);
+
+	return NT_STATUS_OK;
+}