/* 
   Unix SMB/CIFS implementation.
   simple kerberos5 routines for active directory
   Copyright (C) Andrew Tridgell 2001
   Copyright (C) Luke Howard 2002-2003
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 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 "system/network.h"
#include "system/kerberos.h"
#include "system/time.h"
#include "auth/kerberos/kerberos.h"

#ifdef HAVE_KRB5

#ifndef HAVE_KRB5_SET_REAL_TIME
/*
 * This function is not in the Heimdal mainline.
 */
 krb5_error_code krb5_set_real_time(krb5_context context, int32_t seconds, int32_t microseconds)
{
	krb5_error_code ret;
	int32_t sec, usec;

	ret = krb5_us_timeofday(context, &sec, &usec);
	if (ret)
		return ret;

	context->kdc_sec_offset = seconds - sec;
	context->kdc_usec_offset = microseconds - usec;

	return 0;
}
#endif

#if defined(HAVE_KRB5_SET_DEFAULT_IN_TKT_ETYPES) && !defined(HAVE_KRB5_SET_DEFAULT_TGS_KTYPES)
 krb5_error_code krb5_set_default_tgs_ktypes(krb5_context ctx, const krb5_enctype *enc)
{
	return krb5_set_default_in_tkt_etypes(ctx, enc);
}
#endif

#if defined(HAVE_ADDR_TYPE_IN_KRB5_ADDRESS)
/* HEIMDAL */
 void setup_kaddr( krb5_address *pkaddr, struct sockaddr *paddr)
{
	pkaddr->addr_type = KRB5_ADDRESS_INET;
	pkaddr->address.length = sizeof(((struct sockaddr_in *)paddr)->sin_addr);
	pkaddr->address.data = (char *)&(((struct sockaddr_in *)paddr)->sin_addr);
}
#elif defined(HAVE_ADDRTYPE_IN_KRB5_ADDRESS)
/* MIT */
 void setup_kaddr( krb5_address *pkaddr, struct sockaddr *paddr)
{
	pkaddr->addrtype = ADDRTYPE_INET;
	pkaddr->length = sizeof(((struct sockaddr_in *)paddr)->sin_addr);
	pkaddr->contents = (krb5_octet *)&(((struct sockaddr_in *)paddr)->sin_addr);
}
#else
#error UNKNOWN_ADDRTYPE
#endif

#if defined(HAVE_KRB5_PRINCIPAL2SALT) && defined(HAVE_KRB5_USE_ENCTYPE) && defined(HAVE_KRB5_STRING_TO_KEY) && defined(HAVE_KRB5_ENCRYPT_BLOCK)
 int create_kerberos_key_from_string(krb5_context context,
					krb5_principal host_princ,
					krb5_data *password,
					krb5_keyblock *key,
					krb5_enctype enctype)
{
	int ret;
	krb5_data salt;
	krb5_encrypt_block eblock;

	ret = krb5_principal2salt(context, host_princ, &salt);
	if (ret) {
		DEBUG(1,("krb5_principal2salt failed (%s)\n", error_message(ret)));
		return ret;
	}
	krb5_use_enctype(context, &eblock, enctype);
	ret = krb5_string_to_key(context, &eblock, key, password, &salt);
	SAFE_FREE(salt.data);
	return ret;
}
#elif defined(HAVE_KRB5_GET_PW_SALT) && defined(HAVE_KRB5_STRING_TO_KEY_SALT)
 int create_kerberos_key_from_string(krb5_context context,
					krb5_principal host_princ,
					krb5_data *password,
					krb5_keyblock *key,
					krb5_enctype enctype)
{
	int ret;
	krb5_salt salt;

	ret = krb5_get_pw_salt(context, host_princ, &salt);
	if (ret) {
		DEBUG(1,("krb5_get_pw_salt failed (%s)\n", error_message(ret)));
		return ret;
	}
	ret = krb5_string_to_key_salt(context, enctype, password->data,
				      salt, key);
	krb5_free_salt(context, salt);
	return ret;
}
#else
#error UNKNOWN_CREATE_KEY_FUNCTIONS
#endif

#if defined(HAVE_KRB5_GET_PERMITTED_ENCTYPES)
 krb5_error_code get_kerberos_allowed_etypes(krb5_context context, 
					    krb5_enctype **enctypes)
{
	return krb5_get_permitted_enctypes(context, enctypes);
}
#elif defined(HAVE_KRB5_GET_DEFAULT_IN_TKT_ETYPES)
 krb5_error_code get_kerberos_allowed_etypes(krb5_context context, 
					    krb5_enctype **enctypes)
{
	return krb5_get_default_in_tkt_etypes(context, enctypes);
}
#else
#error UNKNOWN_GET_ENCTYPES_FUNCTIONS
#endif

 void free_kerberos_etypes(krb5_context context, 
			   krb5_enctype *enctypes)
{
#if defined(HAVE_KRB5_FREE_KTYPES)
	krb5_free_ktypes(context, enctypes);
	return;
#else
	SAFE_FREE(enctypes);
	return;
#endif
}

#if defined(HAVE_KRB5_AUTH_CON_SETKEY) && !defined(HAVE_KRB5_AUTH_CON_SETUSERUSERKEY)
 krb5_error_code krb5_auth_con_setuseruserkey(krb5_context context,
					krb5_auth_context auth_context,
					krb5_keyblock *keyblock)
{
	return krb5_auth_con_setkey(context, auth_context, keyblock);
}
#endif

#if !defined(HAVE_KRB5_FREE_UNPARSED_NAME)
 void krb5_free_unparsed_name(krb5_context context, char *val)
{
	SAFE_FREE(val);
}
#endif

 void kerberos_free_data_contents(krb5_context context, krb5_data *pdata)
{
#if defined(HAVE_KRB5_FREE_DATA_CONTENTS)
	if (pdata->data) {
		krb5_free_data_contents(context, pdata);
	}
#else
	SAFE_FREE(pdata->data);
#endif
}

 void kerberos_set_creds_enctype(krb5_creds *pcreds, int enctype)
{
#if defined(HAVE_KRB5_KEYBLOCK_IN_CREDS)
	KRB5_KEY_TYPE((&pcreds->keyblock)) = enctype;
#elif defined(HAVE_KRB5_SESSION_IN_CREDS)
	KRB5_KEY_TYPE((&pcreds->session)) = enctype;
#else
#error UNKNOWN_KEYBLOCK_MEMBER_IN_KRB5_CREDS_STRUCT
#endif
}

 BOOL kerberos_compatible_enctypes(krb5_context context,
				  krb5_enctype enctype1,
				  krb5_enctype enctype2)
{
#if defined(HAVE_KRB5_C_ENCTYPE_COMPARE)
	krb5_boolean similar = 0;

	krb5_c_enctype_compare(context, enctype1, enctype2, &similar);
	return similar ? True : False;
#elif defined(HAVE_KRB5_ENCTYPES_COMPATIBLE_KEYS)
	return krb5_enctypes_compatible_keys(context, enctype1, enctype2) ? True : False;
#endif
}

static BOOL ads_cleanup_expired_creds(krb5_context context, 
				      krb5_ccache  ccache,
				      krb5_creds  *credsp)
{
	krb5_error_code retval;
	TALLOC_CTX *mem_ctx = talloc_init("ticket expied time");
	if (!mem_ctx) {
		return False;
	}

	DEBUG(3, ("Ticket in ccache[%s] expiration %s\n",
		  krb5_cc_default_name(context),
		  http_timestring(mem_ctx, credsp->times.endtime)));

	talloc_free(mem_ctx);

	/* we will probably need new tickets if the current ones
	   will expire within 10 seconds.
	*/
	if (credsp->times.endtime >= (time(NULL) + 10))
		return False;

	/* heimdal won't remove creds from a file ccache, and 
	   perhaps we shouldn't anyway, since internally we 
	   use memory ccaches, and a FILE one probably means that
	   we're using creds obtained outside of our exectuable
	*/
	if (strcasecmp_m(krb5_cc_get_type(context, ccache), "FILE") == 0) {
		DEBUG(5, ("ads_cleanup_expired_creds: We do not remove creds from a FILE ccache\n"));
		return False;
	}
	
	retval = krb5_cc_remove_cred(context, ccache, 0, credsp);
	if (retval) {
		DEBUG(1, ("ads_cleanup_expired_creds: krb5_cc_remove_cred failed, err %s\n",
			  error_message(retval)));
		/* If we have an error in this, we want to display it,
		   but continue as though we deleted it */
	}
	return True;
}

/*
  we can't use krb5_mk_req because w2k wants the service to be in a particular format
*/
krb5_error_code ads_krb5_mk_req(krb5_context context, 
				krb5_auth_context *auth_context, 
				const krb5_flags ap_req_options,
				const char *principal,
				krb5_ccache ccache, 
				krb5_data *outbuf)
{
	krb5_error_code 	  retval;
	krb5_principal	  server;
	krb5_creds 		* credsp;
	krb5_creds 		  creds;
	krb5_data in_data;
	BOOL creds_ready = False;
	
	TALLOC_CTX *mem_ctx = NULL;

	retval = krb5_parse_name(context, principal, &server);
	if (retval) {
		DEBUG(1,("ads_krb5_mk_req: Failed to parse principal %s\n", principal));
		return retval;
	}
	
	/* obtain ticket & session key */
	ZERO_STRUCT(creds);
	if ((retval = krb5_copy_principal(context, server, &creds.server))) {
		DEBUG(1,("krb5_copy_principal failed (%s)\n", 
			 error_message(retval)));
		goto cleanup_princ;
	}
	
	if ((retval = krb5_cc_get_principal(context, ccache, &creds.client))) {
		/* This can commonly fail on smbd startup with no ticket in the cache.
		 * Report at higher level than 1. */
		DEBUG(3,("ads_krb5_mk_req: krb5_cc_get_principal failed (%s)\n", 
			 error_message(retval)));
		goto cleanup_creds;
	}

	while(!creds_ready) {
		if ((retval = krb5_get_credentials(context, 0, ccache, 
						   &creds, &credsp))) {
			DEBUG(1,("ads_krb5_mk_req: krb5_get_credentials failed for %s (%s)\n",
				 principal, error_message(retval)));
			goto cleanup_creds;
		}

		/* cope with ticket being in the future due to clock skew */
		if ((unsigned)credsp->times.starttime > time(NULL)) {
			time_t t = time(NULL);
			int time_offset =(unsigned)credsp->times.starttime-t;
			DEBUG(4,("ads_krb5_mk_req: Advancing clock by %d seconds to cope with clock skew\n", time_offset));
			krb5_set_real_time(context, t + time_offset + 1, 0);
		}

		if (!ads_cleanup_expired_creds(context, ccache, credsp))
			creds_ready = True;
	}

	mem_ctx = talloc_init("ticket expied time");
	if (!mem_ctx) {
		retval = ENOMEM;
		goto cleanup_creds;
	}
	DEBUG(10,("Ticket (%s) in ccache (%s) is valid until: (%s - %d)\n",
		  principal, krb5_cc_default_name(context),
		  http_timestring(mem_ctx, (unsigned)credsp->times.endtime), 
		  (unsigned)credsp->times.endtime));
	
	in_data.length = 0;
	retval = krb5_mk_req_extended(context, auth_context, ap_req_options, 
				      &in_data, credsp, outbuf);
	if (retval) {
		DEBUG(1,("ads_krb5_mk_req: krb5_mk_req_extended failed (%s)\n", 
			 error_message(retval)));
	}
	
	krb5_free_creds(context, credsp);

cleanup_creds:
	krb5_free_cred_contents(context, &creds);

cleanup_princ:
	krb5_free_principal(context, server);

	return retval;
}

 krb5_error_code smb_krb5_kt_free_entry(krb5_context context, krb5_keytab_entry *kt_entry)
{
#if defined(HAVE_KRB5_KT_FREE_ENTRY)
	return krb5_kt_free_entry(context, kt_entry);
#elif defined(HAVE_KRB5_FREE_KEYTAB_ENTRY_CONTENTS)
	return krb5_free_keytab_entry_contents(context, kt_entry);
#else
#error UNKNOWN_KT_FREE_FUNCTION
#endif
}

 char *smb_get_krb5_error_message(krb5_context context, krb5_error_code code, TALLOC_CTX *mem_ctx) 
{
	char *ret;
	
#if defined(HAVE_KRB5_GET_ERROR_STRING) && defined(HAVE_KRB5_FREE_ERROR_STRING) 	
	char *context_error = krb5_get_error_string(context);
	if (context_error) {
		ret = talloc_asprintf(mem_ctx, "%s: %s", error_message(code), context_error);
		krb5_free_error_string(context, context_error);
		return ret;
	}
#endif
	ret = talloc_strdup(mem_ctx, error_message(code));
	return ret;
}

#endif