/* 
   Unix SMB/CIFS implementation.
   Authenticate against a remote domain
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Andrew Bartlett 2001
   
   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"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_AUTH

BOOL global_machine_password_needs_changing = False;

extern pstring global_myname;
extern userdom_struct current_user_info;

/**
 * Connect to a remote server for domain security authenticaion.
 *
 * @param cli the cli to return containing the active connection
 * @param server either a machine name or text IP address to
 *               connect to.
 * @param trust_password the trust password to establish the
 *                       credentials with.
 *
 **/

static NTSTATUS connect_to_domain_password_server(struct cli_state **cli, 
						  const char *server, 
						  const char *setup_creds_as,
						  uint16 sec_chan,
						  const unsigned char *trust_passwd)
{
	struct in_addr dest_ip;
	fstring remote_machine;
        NTSTATUS result;

	if (is_ipaddress(server)) {
		struct in_addr to_ip;
	  
		/* we shouldn't have 255.255.255.255 forthe IP address of 
		   a password server anyways */
		if ((to_ip.s_addr=inet_addr(server)) == 0xFFFFFFFF) {
			DEBUG (0,("connect_to_domain_password_server: inet_addr(%s) returned 0xFFFFFFFF!\n", server));
			return NT_STATUS_UNSUCCESSFUL;
		}

		if (!name_status_find("*", 0x20, 0x20, to_ip, remote_machine)) {
			DEBUG(0, ("connect_to_domain_password_server: Can't "
				  "resolve name for IP %s\n", server));
			return NT_STATUS_UNSUCCESSFUL;
		}
	} else {
		fstrcpy(remote_machine, server);
	}

	standard_sub_basic(current_user_info.smb_name, remote_machine);
	strupper(remote_machine);

	if(!resolve_name( remote_machine, &dest_ip, 0x20)) {
		DEBUG(1,("connect_to_domain_password_server: Can't resolve address for %s\n", remote_machine));
		return NT_STATUS_UNSUCCESSFUL;
	}
  
	if (ismyip(dest_ip)) {
		DEBUG(1,("connect_to_domain_password_server: Password server loop - not using password server %s\n",
			 remote_machine));
		return NT_STATUS_UNSUCCESSFUL;
	}
  
	/* TODO: Send a SAMLOGON request to determine whether this is a valid
	   logonserver.  We can avoid a 30-second timeout if the DC is down
	   if the SAMLOGON request fails as it is only over UDP. */

	/* we use a mutex to prevent two connections at once - when a 
	   Win2k PDC get two connections where one hasn't completed a 
	   session setup yet it will send a TCP reset to the first 
	   connection (tridge) */

	/*
	 * With NT4.x DC's *all* authentication must be serialized to avoid
	 * ACCESS_DENIED errors if 2 auths are done from the same machine. JRA.
	 */

	if (!grab_server_mutex(server))
		return NT_STATUS_UNSUCCESSFUL;
	
	/* Attempt connection */
	result = cli_full_connection(cli, global_myname, server,
				     &dest_ip, 0, "IPC$", "IPC", "", "", "", 0);

	if (!NT_STATUS_IS_OK(result)) {
		release_server_mutex();
		return result;
	}

	/*
	 * We now have an anonymous connection to IPC$ on the domain password server.
	 */

	/*
	 * Even if the connect succeeds we need to setup the netlogon
	 * pipe here. We do this as we may just have changed the domain
	 * account password on the PDC and yet we may be talking to
	 * a BDC that doesn't have this replicated yet. In this case
	 * a successful connect to a DC needs to take the netlogon connect
	 * into account also. This patch from "Bjart Kvarme" <bjart.kvarme@usit.uio.no>.
	 */

	if(cli_nt_session_open(*cli, PIPE_NETLOGON) == False) {
		DEBUG(0,("connect_to_domain_password_server: unable to open the domain client session to \
machine %s. Error was : %s.\n", remote_machine, cli_errstr(*cli)));
		cli_nt_session_close(*cli);
		cli_ulogoff(*cli);
		cli_shutdown(*cli);
		release_server_mutex();
		return NT_STATUS_UNSUCCESSFUL;
	}

	snprintf((*cli)->mach_acct, sizeof((*cli)->mach_acct) - 1, "%s$", setup_creds_as);

	if (!(*cli)->mach_acct) {
		release_server_mutex();
		return NT_STATUS_NO_MEMORY;
	}

	result = new_cli_nt_setup_creds(*cli, sec_chan, trust_passwd);

        if (!NT_STATUS_IS_OK(result)) {
		DEBUG(0,("connect_to_domain_password_server: unable to setup the PDC credentials to machine \
%s. Error was : %s.\n", remote_machine, nt_errstr(result)));
		cli_nt_session_close(*cli);
		cli_ulogoff(*cli);
		cli_shutdown(*cli);
		release_server_mutex();
		return result;
	}

	/* We exit here with the mutex *locked*. JRA */

	return NT_STATUS_OK;
}

/***********************************************************************
 Utility function to attempt a connection to an IP address of a DC.
************************************************************************/

static NTSTATUS attempt_connect_to_dc(struct cli_state **cli, 
				      const char *domain, 
				      struct in_addr *ip, 
				      const char *setup_creds_as, 
				      uint16 sec_chan,
				      const unsigned char *trust_passwd)
{
	fstring dc_name;

	/*
	 * Ignore addresses we have already tried.
	 */

	if (is_zero_ip(*ip))
		return NT_STATUS_UNSUCCESSFUL;

	if (!lookup_dc_name(global_myname, domain, ip, dc_name))
		return NT_STATUS_UNSUCCESSFUL;

	return connect_to_domain_password_server(cli, dc_name, setup_creds_as, sec_chan, trust_passwd);
}

/***********************************************************************
 We have been asked to dynamcially determine the IP addresses of
 the PDC and BDC's for DOMAIN, and query them in turn.
************************************************************************/
static NTSTATUS find_connect_pdc(struct cli_state **cli, 
				 const char *domain,
				 const char *setup_creds_as,
				 uint16 sec_chan,
				 unsigned char *trust_passwd, 
				 time_t last_change_time)
{
	struct in_addr *ip_list = NULL;
	int count = 0;
	int i;
	NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
	time_t time_now = time(NULL);
	BOOL use_pdc_only = False;

	/*
	 * If the time the machine password has changed
	 * was less than an hour ago then we need to contact
	 * the PDC only, as we cannot be sure domain replication
	 * has yet taken place. Bug found by Gerald (way to go
	 * Gerald !). JRA.
	 */

	if (time_now - last_change_time < 3600)
		use_pdc_only = True;

	if (!get_dc_list(use_pdc_only, domain, &ip_list, &count))
		return NT_STATUS_UNSUCCESSFUL;

	/*
	 * Firstly try and contact a PDC/BDC who has the same
	 * network address as any of our interfaces.
	 */
	for(i = 0; i < count; i++) {
		if(!is_local_net(ip_list[i]))
			continue;

		if(NT_STATUS_IS_OK(nt_status = 
				   attempt_connect_to_dc(cli, domain, 
							 &ip_list[i], setup_creds_as, 
							 sec_chan, trust_passwd))) 
			break;
		
		zero_ip(&ip_list[i]); /* Tried and failed. */
	}

	/*
	 * Secondly try and contact a random PDC/BDC.
	 */
	if(!NT_STATUS_IS_OK(nt_status)) {
		i = (sys_random() % count);

		if (!is_zero_ip(ip_list[i])) {
			if (!NT_STATUS_IS_OK(nt_status = 
					     attempt_connect_to_dc(cli, domain, 
								   &ip_list[i], setup_creds_as, 
								   sec_chan, trust_passwd)))
				zero_ip(&ip_list[i]); /* Tried and failed. */
		}
	}

	/*
	 * Finally go through the IP list in turn, ignoring any addresses
	 * we have already tried.
	 */
	if(!NT_STATUS_IS_OK(nt_status)) {
		/*
		 * Try and connect to any of the other IP addresses in the PDC/BDC list.
		 * Note that from a WINS server the #1 IP address is the PDC.
		 */
		for(i = 0; i < count; i++) {
			if (is_zero_ip(ip_list[i]))
				continue;

			if (NT_STATUS_IS_OK(nt_status = attempt_connect_to_dc(cli, domain, 
						  &ip_list[i], setup_creds_as, sec_chan, trust_passwd)))
				break;
		}
	}

	SAFE_FREE(ip_list);
	return nt_status;
}

/***********************************************************************
 Do the same as security=server, but using NT Domain calls and a session
 key from the machine password.  If the server parameter is specified
 use it, otherwise figure out a server from the 'password server' param.
************************************************************************/

static NTSTATUS domain_client_validate(TALLOC_CTX *mem_ctx,
				       const auth_usersupplied_info *user_info, 
				       const char *domain,
				       uchar chal[8],
				       auth_serversupplied_info **server_info, 
				       char *server, char *setup_creds_as,
				       uint16 sec_chan,
				       unsigned char trust_passwd[16],
				       time_t last_change_time)
{
	fstring remote_machine;
	NET_USER_INFO_3 info3;
	struct cli_state *cli = NULL;
	NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;

	/*
	 * At this point, smb_apasswd points to the lanman response to
	 * the challenge in local_challenge, and smb_ntpasswd points to
	 * the NT response to the challenge in local_challenge. Ship
	 * these over the secure channel to a domain controller and
	 * see if they were valid.
	 */

	while (!NT_STATUS_IS_OK(nt_status) &&
	       next_token(&server,remote_machine,LIST_SEP,sizeof(remote_machine))) {
		if(strequal(remote_machine, "*")) {
			nt_status = find_connect_pdc(&cli, domain, setup_creds_as, sec_chan, trust_passwd, last_change_time);
		} else {
			nt_status = connect_to_domain_password_server(&cli, remote_machine, setup_creds_as, sec_chan, trust_passwd);
		}
	}

	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(0,("domain_client_validate: Domain password server not available.\n"));
		return nt_status;
	}

	ZERO_STRUCT(info3);

        /*
         * If this call succeeds, we now have lots of info about the user
         * in the info3 structure.  
         */

	nt_status = cli_netlogon_sam_network_logon(cli, mem_ctx,
						   user_info->smb_name.str, user_info->domain.str, 
						   user_info->wksta_name.str, chal, 
						   user_info->lm_resp, user_info->nt_resp, 
						   &info3);
        
	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(0,("domain_client_validate: unable to validate password "
                         "for user %s in domain %s to Domain controller %s. "
                         "Error was %s.\n", user_info->smb_name.str,
                         user_info->domain.str, cli->srv_name_slash, 
                         nt_errstr(nt_status)));
	} else {
		nt_status = make_server_info_info3(mem_ctx, user_info->internal_username.str, 
						   user_info->smb_name.str, domain, server_info, &info3);
#if 0 
		/* The stuff doesn't work right yet */
		SMB_ASSERT(sizeof((*server_info)->session_key) == sizeof(info3.user_sess_key)); 
		memcpy((*server_info)->session_key, info3.user_sess_key, sizeof((*server_info)->session_key)/* 16 */);
		SamOEMhash((*server_info)->session_key, trust_passwd, sizeof((*server_info)->session_key));
#endif		

		uni_group_cache_store_netlogon(mem_ctx, &info3);
	}

#if 0
	/* 
	 * We don't actually need to do this - plus it fails currently with
	 * NT_STATUS_INVALID_INFO_CLASS - we need to know *exactly* what to
	 * send here. JRA.
	 */

	if (NT_STATUS_IS_OK(status)) {
		if(cli_nt_logoff(&cli, &ctr) == False) {
			DEBUG(0,("domain_client_validate: unable to log off user %s in domain \
%s to Domain controller %s. Error was %s.\n", user, domain, remote_machine, cli_errstr(&cli)));        
			nt_status = NT_STATUS_LOGON_FAILURE;
		}
	}
#endif /* 0 */

	/* Note - once the cli stream is shutdown the mem_ctx used
	   to allocate the other_sids and gids structures has been deleted - so
	   these pointers are no longer valid..... */

	cli_nt_session_close(cli);
	cli_ulogoff(cli);
	cli_shutdown(cli);
	release_server_mutex();
	return nt_status;
}

/****************************************************************************
 Check for a valid username and password in security=domain mode.
****************************************************************************/

static NTSTATUS check_ntdomain_security(const struct auth_context *auth_context,
					void *my_private_data, 
					TALLOC_CTX *mem_ctx,
					const auth_usersupplied_info *user_info, 
					auth_serversupplied_info **server_info)
{
	NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
	char *password_server;
	unsigned char trust_passwd[16];
	time_t last_change_time;
	char *domain = lp_workgroup();

	if (!user_info || !server_info || !auth_context) {
		DEBUG(1,("check_ntdomain_security: Critical variables not present.  Failing.\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	/* 
	 * Check that the requested domain is not our own machine name.
	 * If it is, we should never check the PDC here, we use our own local
	 * password file.
	 */

	if(is_netbios_alias_or_name(user_info->domain.str)) {
		DEBUG(3,("check_ntdomain_security: Requested domain was for this machine.\n"));
		return NT_STATUS_LOGON_FAILURE;
	}

	/*
	 * Get the machine account password for our primary domain
	 * No need to become_root() as secrets_init() is done at startup.
	 */

	if (!secrets_fetch_trust_account_password(domain, trust_passwd, &last_change_time))
	{
		DEBUG(0, ("check_ntdomain_security: could not fetch trust account password for domain %s\n", lp_workgroup()));
		return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
	}

	/* Test if machine password is expired and need to be changed */
	if (time(NULL) > last_change_time + lp_machine_password_timeout())
	{
		global_machine_password_needs_changing = True;
	}

	/*
	 * Treat each name in the 'password server =' line as a potential
	 * PDC/BDC. Contact each in turn and try and authenticate.
	 */

	password_server = lp_passwordserver();

	nt_status = domain_client_validate(mem_ctx, user_info, domain,
					   (uchar *)auth_context->challenge.data, 
					   server_info, 
					   password_server, global_myname, SEC_CHAN_WKSTA, trust_passwd, last_change_time);
	return nt_status;
}

/* module initialisation */
NTSTATUS auth_init_ntdomain(struct auth_context *auth_context, const char* param, auth_methods **auth_method) 
{
	if (!make_auth_methods(auth_context, auth_method)) {
		return NT_STATUS_NO_MEMORY;
	}

	(*auth_method)->name = "ntdomain";
	(*auth_method)->auth = check_ntdomain_security;
	return NT_STATUS_OK;
}


/****************************************************************************
 Check for a valid username and password in a trusted domain
****************************************************************************/

static NTSTATUS check_trustdomain_security(const struct auth_context *auth_context,
					   void *my_private_data, 
					   TALLOC_CTX *mem_ctx,
					   const auth_usersupplied_info *user_info, 
					   auth_serversupplied_info **server_info)
{
	NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
	unsigned char trust_md4_password[16];
	char *trust_password;
	time_t last_change_time;
	DOM_SID sid;

	if (!user_info || !server_info || !auth_context) {
		DEBUG(1,("check_trustdomain_security: Critical variables not present.  Failing.\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	/* 
	 * Check that the requested domain is not our own machine name.
	 * If it is, we should never check the PDC here, we use our own local
	 * password file.
	 */

	if(is_netbios_alias_or_name(user_info->domain.str)) {
		DEBUG(3,("check_trustdomain_security: Requested domain was for this machine.\n"));
		return NT_STATUS_LOGON_FAILURE;
	}

	/* 
	 * Check that the requested domain is not our own domain,
	 * If it is, we should use our own local password file.
	 */

	if(strequal(lp_workgroup(), (user_info->domain.str))) {
		DEBUG(3,("check_trustdomain_security: Requested domain was for this domain.\n"));
		return NT_STATUS_LOGON_FAILURE;
	}

	/*
	 * Get the trusted account password for the trusted domain
	 * No need to become_root() as secrets_init() is done at startup.
	 */

	if (!secrets_fetch_trusted_domain_password(user_info->domain.str, &trust_password, &sid, &last_change_time))
	{
		DEBUG(0, ("check_trustdomain_security: could not fetch trust account password for domain %s\n", user_info->domain.str));
		return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
	}

#ifdef DEBUG_PASSWORD
	DEBUG(100, ("Trust password for domain %s is %s\n", user_info->domain.str, trust_password));
#endif
	E_md4hash((uchar *)trust_password, trust_md4_password);
	SAFE_FREE(trust_password);

#if 0
	/* Test if machine password is expired and need to be changed */
	if (time(NULL) > last_change_time + lp_machine_password_timeout())
	{
		global_machine_password_needs_changing = True;
	}
#endif

	nt_status = domain_client_validate(mem_ctx, user_info, user_info->domain.str,
					   (uchar *)auth_context->challenge.data, 
					   server_info, "*" /* Do a lookup */, 
					   lp_workgroup(), SEC_CHAN_DOMAIN, trust_md4_password, last_change_time);
	
	return nt_status;
}

/* module initialisation */
NTSTATUS auth_init_trustdomain(struct auth_context *auth_context, const char* param, auth_methods **auth_method) 
{
	if (!make_auth_methods(auth_context, auth_method)) {
		return NT_STATUS_NO_MEMORY;
	}

	(*auth_method)->name = "trustdomain";
	(*auth_method)->auth = check_trustdomain_security;
	return NT_STATUS_OK;
}