ntlmssp_server.c

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static NTSTATUS ntlmssp_server_postauth(struct gensec_security *gensec_security, 
					DATA_BLOB *user_session_key, 
					DATA_BLOB *lm_session_key) 
{
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = (struct gensec_ntlmssp_state *)gensec_security->private_data;
	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 (gensec_ntlmssp_state->doing_ntlm2) {
		if (user_session_key && user_session_key->data && user_session_key->length == 16) {
			session_key = data_blob_talloc(gensec_ntlmssp_state, NULL, 16);
			hmac_md5(user_session_key->data, gensec_ntlmssp_state->crypt.ntlm2.session_nonce, 
				 sizeof(gensec_ntlmssp_state->crypt.ntlm2.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 ((gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) 
		/* Ensure we can never get here on NTLMv2 */
		&& (gensec_ntlmssp_state->nt_resp.length == 0 || gensec_ntlmssp_state->nt_resp.length == 24)) {

		if (lm_session_key && lm_session_key->data && lm_session_key->length >= 8) {
			if (gensec_ntlmssp_state->lm_resp.data && gensec_ntlmssp_state->lm_resp.length == 24) {
				session_key = data_blob_talloc(gensec_ntlmssp_state, NULL, 16);
				SMBsesskeygen_lm_sess_key(lm_session_key->data, gensec_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(gensec_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 */
 			gensec_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 */
		gensec_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 */
		gensec_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 */
		gensec_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 (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
		if (!gensec_ntlmssp_state->encrypted_session_key.data 
		    || gensec_ntlmssp_state->encrypted_session_key.length != 16) {
			data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);
			DEBUG(1, ("Client-supplied KEY_EXCH session key was of invalid length (%u)!\n", 
				  (unsigned)gensec_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", 
				  (unsigned)session_key.length));
			gensec_ntlmssp_state->session_key = session_key;
		} else {
			dump_data_pw("KEY_EXCH session key (enc):\n", 
				     gensec_ntlmssp_state->encrypted_session_key.data, 
				     gensec_ntlmssp_state->encrypted_session_key.length);
			arcfour_crypt(gensec_ntlmssp_state->encrypted_session_key.data, 
				      session_key.data, 
				      gensec_ntlmssp_state->encrypted_session_key.length);
			gensec_ntlmssp_state->session_key = data_blob_talloc(gensec_ntlmssp_state, 
								      gensec_ntlmssp_state->encrypted_session_key.data, 
								      gensec_ntlmssp_state->encrypted_session_key.length);
			dump_data_pw("KEY_EXCH session key:\n", gensec_ntlmssp_state->encrypted_session_key.data, 
				     gensec_ntlmssp_state->encrypted_session_key.length);
		}
	} else {
		gensec_ntlmssp_state->session_key = session_key;
	}

	/* keep the session key around on the new context */
	talloc_steal(gensec_ntlmssp_state, session_key.data);

	if ((gensec_security->want_features & GENSEC_FEATURE_SIGN)
	    || (gensec_security->want_features & GENSEC_FEATURE_SEAL)) {
		nt_status = ntlmssp_sign_init(gensec_ntlmssp_state);
	} else {
		nt_status = NT_STATUS_OK;
	}

	data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);
	
	/* allow arbitarily many authentications, but watch that this will cause a 
	   memory leak, until the gensec_ntlmssp_state is shutdown 
	*/

	if (gensec_ntlmssp_state->server_multiple_authentications) {
		gensec_ntlmssp_state->expected_state = NTLMSSP_AUTH;
	} else {
		gensec_ntlmssp_state->expected_state = NTLMSSP_DONE;
	}

	return nt_status;
}


/**
 * Next state function for the Authenticate packet
 * 
 * @param gensec_security GENSEC state
 * @param out_mem_ctx Memory context for *out
 * @param in The request, as a DATA_BLOB.  reply.data must be NULL
 * @param out The reply, as an allocated DATA_BLOB, caller to free.
 * @return Errors or NT_STATUS_OK if authentication sucessful
 */

NTSTATUS ntlmssp_server_auth(struct gensec_security *gensec_security, 
			     TALLOC_CTX *out_mem_ctx, 
			     const DATA_BLOB in, DATA_BLOB *out) 
{	
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = (struct gensec_ntlmssp_state *)gensec_security->private_data;
	DATA_BLOB user_session_key = data_blob(NULL, 0);
	DATA_BLOB lm_session_key = data_blob(NULL, 0);
	NTSTATUS nt_status;

	TALLOC_CTX *mem_ctx = talloc_new(out_mem_ctx);
	if (!mem_ctx) {
		return NT_STATUS_NO_MEMORY;
	}

	/* zero the outbound NTLMSSP packet */
	*out = data_blob_talloc(out_mem_ctx, NULL, 0);

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_server_preauth(gensec_ntlmssp_state, in))) {
		talloc_free(mem_ctx);
		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 = gensec_ntlmssp_state->check_password(gensec_ntlmssp_state, mem_ctx,
									      &user_session_key, &lm_session_key))) {
		talloc_free(mem_ctx);
		return nt_status;
	}
	
	if (gensec_security->want_features
	    & (GENSEC_FEATURE_SIGN|GENSEC_FEATURE_SEAL|GENSEC_FEATURE_SESSION_KEY)) {
		nt_status = ntlmssp_server_postauth(gensec_security, &user_session_key, &lm_session_key);
		talloc_free(mem_ctx);
		return nt_status;
	} else {
		gensec_ntlmssp_state->session_key = data_blob(NULL, 0);
		talloc_free(mem_ctx);
		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 gensec_ntlmssp_state *gensec_ntlmssp_state)
{
	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 gensec_ntlmssp_state *gensec_ntlmssp_state)
{
	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 gensec_ntlmssp_state *gensec_ntlmssp_state, DATA_BLOB *challenge)
{
	NTSTATUS nt_status;
	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 gensec_ntlmssp_state *gensec_ntlmssp_state, 
					    TALLOC_CTX *mem_ctx, 
					    DATA_BLOB *user_session_key, DATA_BLOB *lm_session_key) 
{
	NTSTATUS nt_status;
	struct auth_usersupplied_info *user_info = talloc(mem_ctx, struct auth_usersupplied_info);
	if (!user_info) {
		return NT_STATUS_NO_MEMORY;
	}

	user_info->logon_parameters = MSV1_0_ALLOW_SERVER_TRUST_ACCOUNT | MSV1_0_ALLOW_WORKSTATION_TRUST_ACCOUNT;
	user_info->flags = 0;
	user_info->mapped_state = false;
	user_info->client.account_name = gensec_ntlmssp_state->user;
	user_info->client.domain_name = gensec_ntlmssp_state->domain;
	user_info->workstation_name = gensec_ntlmssp_state->workstation;
	user_info->remote_host = gensec_get_peer_addr(gensec_ntlmssp_state->gensec_security);

	user_info->password_state = AUTH_PASSWORD_RESPONSE;
	user_info->password.response.lanman = gensec_ntlmssp_state->lm_resp;
	user_info->password.response.lanman.data = talloc_steal(user_info, gensec_ntlmssp_state->lm_resp.data);
	user_info->password.response.nt = gensec_ntlmssp_state->nt_resp;
	user_info->password.response.nt.data = talloc_steal(user_info, gensec_ntlmssp_state->nt_resp.data);

	nt_status = auth_check_password(gensec_ntlmssp_state->auth_context, mem_ctx,
					user_info, &gensec_ntlmssp_state->server_info);
	talloc_free(user_info);
	NT_STATUS_NOT_OK_RETURN(nt_status);

	talloc_steal(gensec_ntlmssp_state, gensec_ntlmssp_state->server_info);

	if (gensec_ntlmssp_state->server_info->user_session_key.length) {
		DEBUG(10, ("Got NT session key of length %u\n", 
			   (unsigned)gensec_ntlmssp_state->server_info->user_session_key.length));
		if (!talloc_reference(mem_ctx, gensec_ntlmssp_state->server_info->user_session_key.data)) {
			return NT_STATUS_NO_MEMORY;
		}

		*user_session_key = gensec_ntlmssp_state->server_info->user_session_key;
	}
	if (gensec_ntlmssp_state->server_info->lm_session_key.length) {
		DEBUG(10, ("Got LM session key of length %u\n", 
			   (unsigned)gensec_ntlmssp_state->server_info->lm_session_key.length));
		if (!talloc_reference(mem_ctx, gensec_ntlmssp_state->server_info->lm_session_key.data)) {
			return NT_STATUS_NO_MEMORY;
		}

		*lm_session_key = gensec_ntlmssp_state->server_info->lm_session_key;
	}
	return nt_status;
}

/** 
 * 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 = (struct gensec_ntlmssp_state *)gensec_security->private_data;

	nt_status = auth_generate_session_info(gensec_ntlmssp_state, gensec_security->event_ctx, gensec_security->lp_ctx, 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->session_key.data,
							gensec_ntlmssp_state->session_key.length);

	return NT_STATUS_OK;
}

/**
 * Start NTLMSSP on the server side 
 *
 */
NTSTATUS gensec_ntlmssp_server_start(struct gensec_security *gensec_security)
{
	NTSTATUS nt_status;
	struct gensec_ntlmssp_state *gensec_ntlmssp_state;

	nt_status = gensec_ntlmssp_start(gensec_security);
	NT_STATUS_NOT_OK_RETURN(nt_status);

	gensec_ntlmssp_state = (struct gensec_ntlmssp_state *)gensec_security->private_data;

	gensec_ntlmssp_state->role = NTLMSSP_SERVER;

	gensec_ntlmssp_state->workstation = NULL;
	gensec_ntlmssp_state->server_name = lp_netbios_name(gensec_security->lp_ctx);

	gensec_ntlmssp_state->domain = lp_workgroup(gensec_security->lp_ctx);

	gensec_ntlmssp_state->expected_state = NTLMSSP_NEGOTIATE;

	gensec_ntlmssp_state->allow_lm_key = (lp_lanman_auth(gensec_security->lp_ctx) 
					  && lp_parm_bool(gensec_security->lp_ctx, NULL, "ntlmssp_server", "allow_lm_key", false));

	gensec_ntlmssp_state->server_multiple_authentications = false;
	
	gensec_ntlmssp_state->neg_flags = 
		NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_UNKNOWN_02000000;

	gensec_ntlmssp_state->lm_resp = data_blob(NULL, 0);
	gensec_ntlmssp_state->nt_resp = data_blob(NULL, 0);
	gensec_ntlmssp_state->encrypted_session_key = data_blob(NULL, 0);

	if (lp_parm_bool(gensec_security->lp_ctx, NULL, "ntlmssp_server", "128bit", true)) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_128;		
	}

	if (lp_parm_bool(gensec_security->lp_ctx, NULL, "ntlmssp_server", "56bit", true)) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_56;		
	}

	if (lp_parm_bool(gensec_security->lp_ctx, NULL, "ntlmssp_server", "keyexchange", true)) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_KEY_EXCH;		
	}

	if (lp_parm_bool(gensec_security->lp_ctx, NULL, "ntlmssp_server", "alwayssign", true)) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_ALWAYS_SIGN;		
	}

	if (lp_parm_bool(gensec_security->lp_ctx, NULL, "ntlmssp_server", "ntlm2", true)) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_NTLM2;		
	}

	if (gensec_security->want_features & GENSEC_FEATURE_SIGN) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SIGN;
	}
	if (gensec_security->want_features & GENSEC_FEATURE_SEAL) {
		gensec_ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
	}

	nt_status = auth_context_create(gensec_ntlmssp_state, 
					gensec_security->event_ctx,
					gensec_security->msg_ctx,
					gensec_security->lp_ctx,
					&gensec_ntlmssp_state->auth_context);
	NT_STATUS_NOT_OK_RETURN(nt_status);

	gensec_ntlmssp_state->get_challenge = auth_ntlmssp_get_challenge;
	gensec_ntlmssp_state->may_set_challenge = auth_ntlmssp_may_set_challenge;
	gensec_ntlmssp_state->set_challenge = auth_ntlmssp_set_challenge;
	gensec_ntlmssp_state->check_password = auth_ntlmssp_check_password;
	gensec_ntlmssp_state->server_role = lp_server_role(gensec_security->lp_ctx);

	return NT_STATUS_OK;
}