/*
   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> 2005-2011
   Copyright (C) Guenther Deschner 2005-2009

   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"
#ifdef HAVE_KRB5

#include "libcli/auth/krb5_wrap.h"
#include "librpc/gen_ndr/krb5pac.h"

#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_direct(krb5_context context,
						  krb5_principal host_princ,
						  krb5_data *password,
						  krb5_keyblock *key,
						  krb5_enctype enctype)
{
	int ret = 0;
	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_direct(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, (const char *)password->data, salt, key);
	krb5_free_salt(context, salt);

	return ret;
}
#else
#error UNKNOWN_CREATE_KEY_FUNCTIONS
#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);
	}
#elif defined(HAVE_KRB5_DATA_FREE)
	krb5_data_free(context, pdata);
#else
	SAFE_FREE(pdata->data);
#endif
}


 krb5_error_code smb_krb5_kt_free_entry(krb5_context context, krb5_keytab_entry *kt_entry)
{
/* Try krb5_free_keytab_entry_contents first, since
 * MIT Kerberos >= 1.7 has both krb5_free_keytab_entry_contents and
 * krb5_kt_free_entry but only has a prototype for the first, while the
 * second is considered private.
 */
#if defined(HAVE_KRB5_FREE_KEYTAB_ENTRY_CONTENTS)
	return krb5_free_keytab_entry_contents(context, kt_entry);
#elif defined(HAVE_KRB5_KT_FREE_ENTRY)
	return krb5_kt_free_entry(context, kt_entry);
#else
#error UNKNOWN_KT_FREE_FUNCTION
#endif
}

/**************************************************************
 Wrappers around kerberos string functions that convert from
 utf8 -> unix charset and vica versa.
**************************************************************/

/**************************************************************
 krb5_parse_name that takes a UNIX charset.
**************************************************************/

 krb5_error_code smb_krb5_parse_name(krb5_context context,
				const char *name, /* in unix charset */
				krb5_principal *principal)
{
	krb5_error_code ret;
	char *utf8_name;
	size_t converted_size;

	if (!push_utf8_talloc(talloc_tos(), &utf8_name, name, &converted_size)) {
		return ENOMEM;
	}

	ret = krb5_parse_name(context, utf8_name, principal);
	TALLOC_FREE(utf8_name);
	return ret;
}

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

/**************************************************************
 krb5_parse_name that returns a UNIX charset name. Must
 be freed with talloc_free() call.
**************************************************************/

krb5_error_code smb_krb5_unparse_name(TALLOC_CTX *mem_ctx,
				      krb5_context context,
				      krb5_const_principal principal,
				      char **unix_name)
{
	krb5_error_code ret;
	char *utf8_name;
	size_t converted_size;

	*unix_name = NULL;
	ret = krb5_unparse_name(context, principal, &utf8_name);
	if (ret) {
		return ret;
	}

	if (!pull_utf8_talloc(mem_ctx, unix_name, utf8_name, &converted_size)) {
		krb5_free_unparsed_name(context, utf8_name);
		return ENOMEM;
	}
	krb5_free_unparsed_name(context, utf8_name);
	return 0;
}

 krb5_error_code smb_krb5_parse_name_norealm(krb5_context context, 
					    const char *name, 
					    krb5_principal *principal)
{
#ifdef HAVE_KRB5_PARSE_NAME_NOREALM
	return smb_krb5_parse_name_norealm_conv(context, name, principal);
#endif

	/* we are cheating here because parse_name will in fact set the realm.
	 * We don't care as the only caller of smb_krb5_parse_name_norealm
	 * ignores the realm anyway when calling
	 * smb_krb5_principal_compare_any_realm later - Guenther */

	return smb_krb5_parse_name(context, name, principal);
}

 bool smb_krb5_principal_compare_any_realm(krb5_context context, 
					  krb5_const_principal princ1, 
					  krb5_const_principal princ2)
{
#ifdef HAVE_KRB5_PRINCIPAL_COMPARE_ANY_REALM

	return krb5_principal_compare_any_realm(context, princ1, princ2);

/* krb5_princ_size is a macro in MIT */
#elif defined(HAVE_KRB5_PRINC_SIZE) || defined(krb5_princ_size)

	int i, len1, len2;
	const krb5_data *p1, *p2;

	len1 = krb5_princ_size(context, princ1);
	len2 = krb5_princ_size(context, princ2);

	if (len1 != len2)
		return False;

	for (i = 0; i < len1; i++) {

		p1 = krb5_princ_component(context, CONST_DISCARD(krb5_principal, princ1), i);
		p2 = krb5_princ_component(context, CONST_DISCARD(krb5_principal, princ2), i);

		if (p1->length != p2->length ||	memcmp(p1->data, p2->data, p1->length))
			return False;
	}

	return True;
#else
#error NO_SUITABLE_PRINCIPAL_COMPARE_FUNCTION
#endif
}

 void smb_krb5_checksum_from_pac_sig(krb5_checksum *cksum,
				     struct PAC_SIGNATURE_DATA *sig)
{
#ifdef HAVE_CHECKSUM_IN_KRB5_CHECKSUM
	cksum->cksumtype	= (krb5_cksumtype)sig->type;
	cksum->checksum.length	= sig->signature.length;
	cksum->checksum.data	= sig->signature.data;
#else
	cksum->checksum_type	= (krb5_cksumtype)sig->type;
	cksum->length		= sig->signature.length;
	cksum->contents		= sig->signature.data;
#endif
}

 krb5_error_code smb_krb5_verify_checksum(krb5_context context,
					  const krb5_keyblock *keyblock,
					 krb5_keyusage usage,
					 krb5_checksum *cksum,
					 uint8_t *data,
					 size_t length)
{
	krb5_error_code ret;

	/* verify the checksum */

	/* welcome to the wonderful world of samba's kerberos abstraction layer:
	 * 
	 * function			heimdal 0.6.1rc3	heimdal 0.7	MIT krb 1.4.2
	 * -----------------------------------------------------------------------------
	 * krb5_c_verify_checksum	-			works		works
	 * krb5_verify_checksum		works (6 args)		works (6 args)	broken (7 args) 
	 */

#if defined(HAVE_KRB5_C_VERIFY_CHECKSUM)
	{
		krb5_boolean checksum_valid = false;
		krb5_data input;

		input.data = (char *)data;
		input.length = length;

		ret = krb5_c_verify_checksum(context, 
					     keyblock, 
					     usage,
					     &input, 
					     cksum,
					     &checksum_valid);
		if (ret) {
			DEBUG(3,("smb_krb5_verify_checksum: krb5_c_verify_checksum() failed: %s\n", 
				error_message(ret)));
			return ret;
		}

		if (!checksum_valid)
			ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
	}

#elif KRB5_VERIFY_CHECKSUM_ARGS == 6 && defined(HAVE_KRB5_CRYPTO_INIT) && defined(HAVE_KRB5_CRYPTO) && defined(HAVE_KRB5_CRYPTO_DESTROY)

	/* Warning: MIT's krb5_verify_checksum cannot be used as it will use a key
	 * without enctype and it ignores any key_usage types - Guenther */

	{

		krb5_crypto crypto;
		ret = krb5_crypto_init(context,
				       keyblock,
				       0,
				       &crypto);
		if (ret) {
			DEBUG(0,("smb_krb5_verify_checksum: krb5_crypto_init() failed: %s\n", 
				error_message(ret)));
			return ret;
		}

		ret = krb5_verify_checksum(context,
					   crypto,
					   usage,
					   data,
					   length,
					   cksum);

		krb5_crypto_destroy(context, crypto);
	}

#else
#error UNKNOWN_KRB5_VERIFY_CHECKSUM_FUNCTION
#endif

	return ret;
}

 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_MESSAGE) && defined(HAVE_KRB5_FREE_ERROR_MESSAGE)
	const char *context_error = krb5_get_error_message(context, code);
	if (context_error) {
		ret = talloc_asprintf(mem_ctx, "%s: %s", error_message(code), context_error);
		krb5_free_error_message(context, context_error);
		return ret;
	}
#endif
	ret = talloc_strdup(mem_ctx, error_message(code));
	return ret;
}

#endif