/*

 * adcli

 *

 * Copyright (C) 2012 Red Hat Inc.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation; either version 2.1 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 * MA 02110-1301 USA

 *

 * Author: Stef Walter <stefw@gnome.org>

 */

#include "config.h"

#include "adcli.h"

#include "adprivate.h"

#include <gssapi/gssapi_krb5.h>

#include <krb5/krb5.h>

#include <assert.h>

#include <ctype.h>

#include <errno.h>

#include <stdio.h>

krb5_error_code

_adcli_krb5_build_principal (krb5_context k5,

                             const char *user,

                             const char *realm,

                             krb5_principal *principal)

{

	krb5_error_code code;

	char *name = NULL;

	/* Use user if user contains a @-character and add @realm otherwise */

	if (strchr (user, '@') == NULL) {

		if (asprintf (&name, "%s@%s", user, realm) < 0) {

			return_val_if_reached (ENOMEM);

		}

	}

	code = krb5_parse_name (k5, name != NULL ? name : user, principal);

	return_val_if_fail (code == 0, code);

	free (name);

	return 0;

}

krb5_error_code

_adcli_krb5_keytab_clear (krb5_context k5,

                          krb5_keytab keytab,

                          krb5_boolean (* match_func) (krb5_context,

                                                       krb5_keytab_entry *,

                                                       void *),

                          void *match_data)

{

	krb5_kt_cursor cursor;

	krb5_keytab_entry entry;

	krb5_error_code code;

	code = krb5_kt_start_seq_get (k5, keytab, &cursor);

	if (code == KRB5_KT_END || code == ENOENT)

		return 0;

	else if (code != 0)

		return code;

	for (;;) {

		code = krb5_kt_next_entry (k5, keytab, &entry, &cursor);

		if (code != 0)

			break;

		/* See if we should remove this entry */

		if (!match_func (k5, &entry, match_data)) {

			krb5_free_keytab_entry_contents (k5, &entry);

			continue;

		}

		/*

		 * Here we close the cursor, remove the entry and then

		 * start all over again from the beginning. Dumb but works.

		 */

		code = krb5_kt_end_seq_get (k5, keytab, &cursor);

		return_val_if_fail (code == 0, code);

		code = krb5_kt_remove_entry (k5, keytab, &entry);

		krb5_free_keytab_entry_contents (k5, &entry);

		if (code != 0)

			return code;

		code = krb5_kt_start_seq_get (k5, keytab, &cursor);

		return_val_if_fail (code == 0, code);

	}

	if (code == KRB5_KT_END)

		code = 0;

	krb5_kt_end_seq_get (k5, keytab, &cursor);

	return code;

}

static krb5_boolean

match_all_entries (krb5_context k5,

                   krb5_keytab_entry *entry,

                   void *data)

{

	return TRUE;

}

krb5_error_code

_adcli_krb5_keytab_clear_all (krb5_context k5,

                              krb5_keytab keytab)

{

	return _adcli_krb5_keytab_clear (k5, keytab,

	                                 match_all_entries,

	                                 NULL);

}

krb5_error_code

_adcli_krb5_keytab_enumerate (krb5_context k5,

		              krb5_keytab keytab,

                              krb5_boolean (* match_func) (krb5_context,

                                                           krb5_keytab_entry *,

                                                           void *),

                              void *match_data)

{

	krb5_kt_cursor cursor;

	krb5_keytab_entry entry;

	krb5_error_code code;

	code = krb5_kt_start_seq_get (k5, keytab, &cursor);

	if (code == KRB5_KT_END || code == ENOENT)

		return 0;

	else if (code != 0)

		return code;

	for (;;) {

		code = krb5_kt_next_entry (k5, keytab, &entry, &cursor);

		if (code != 0)

			break;

		/* See if we should continue */

		if (!match_func (k5, &entry, match_data))

			break;

	}

	if (code == KRB5_KT_END)

		code = 0;

	krb5_kt_end_seq_get (k5, keytab, &cursor);

	return code;

}

adcli_result

_adcli_krb5_init_context (krb5_context *k5)

{

	krb5_error_code code;

	code = krb5_init_context (k5);

	if (code == ENOMEM) {

		return_unexpected_if_reached ();

	} else if (code != 0) {

		_adcli_err ("Failed to create kerberos context: %s",

		            krb5_get_error_message (NULL, code));

		return ADCLI_ERR_UNEXPECTED;

	}

	return ADCLI_SUCCESS;

}

adcli_result

_adcli_krb5_open_keytab (krb5_context k5,

                         const char *keytab_name,

		         krb5_keytab *keytab)

{

	krb5_error_code code;

	if (keytab_name && strcmp (keytab_name, "") != 0) {

		code = krb5_kt_resolve (k5, keytab_name, keytab);

		if (code != 0) {

			_adcli_err ("Failed to open keytab: %s: %s",

			            keytab_name, krb5_get_error_message (k5, code));

			return ADCLI_ERR_FAIL;

		}

	} else {

		code = krb5_kt_default (k5, keytab);

		if (code != 0) {

			_adcli_err ("Failed to open default keytab: %s",

			            krb5_get_error_message (k5, code));

			return ADCLI_ERR_FAIL;

		}

	}

	return ADCLI_SUCCESS;

}

typedef struct {

	krb5_kvno kvno;

	krb5_enctype enctype;

	int matched;

} match_enctype_kvno;

static krb5_boolean

match_enctype_and_kvno (krb5_context k5,

                        krb5_keytab_entry *entry,

                        void *data)

{

	krb5_boolean similar = FALSE;

	match_enctype_kvno *closure = data;

	krb5_error_code code;

	assert (closure->enctype);

	code = krb5_c_enctype_compare (k5, closure->enctype, entry->key.enctype,

	                               &similar);

	if (code == 0 && entry->vno == closure->kvno && similar) {

		closure->matched = 1;

		return 1;

	}

	return 0;

}

static krb5_error_code

_adcli_krb5_get_keyblock (krb5_context k5,

                          krb5_keytab keytab,

                          krb5_keyblock *keyblock,

                          krb5_boolean (* match_func) (krb5_context,

                                                       krb5_keytab_entry *,

                                                       void *),

                          void *match_data)

{

	krb5_kt_cursor cursor;

	krb5_keytab_entry entry;

	krb5_error_code code;

	code = krb5_kt_start_seq_get (k5, keytab, &cursor);

	if (code == KRB5_KT_END || code == ENOENT)

		return 0;

	else if (code != 0)

		return code;

	for (;;) {

		code = krb5_kt_next_entry (k5, keytab, &entry, &cursor);

		if (code != 0)

			break;

		/* See if we should remove this entry */

		if (!match_func (k5, &entry, match_data)) {

			krb5_free_keytab_entry_contents (k5, &entry);

			continue;

		}

		code = krb5_copy_keyblock_contents (k5, &entry.key, keyblock);

		krb5_free_keytab_entry_contents (k5, &entry);

		break;

	}

	if (code == KRB5_KT_END)

		code = 0;

	krb5_kt_end_seq_get (k5, keytab, &cursor);

	return code;

}

krb5_error_code

_adcli_krb5_keytab_copy_entries (krb5_context k5,

                                 krb5_keytab keytab,

                                 krb5_principal principal,

                                 krb5_kvno kvno,

                                 krb5_enctype *enctypes)

{

	krb5_keytab_entry entry;

	krb5_error_code code;

	int i;

	match_enctype_kvno closure;

	for (i = 0; enctypes[i] != 0; i++) {

		closure.kvno = kvno;

		closure.enctype = enctypes[i];

		closure.matched = 0;

		memset (&entry, 0, sizeof (entry));

		code = _adcli_krb5_get_keyblock (k5, keytab, &entry.key,

		                                 match_enctype_and_kvno, &closure);

		if (code != 0 || closure.matched == 0) {

			return code != 0 ? code : ENOKEY;

		}

		entry.principal = principal;

		entry.vno = kvno;

		code = krb5_kt_add_entry (k5, keytab, &entry);

		entry.principal = NULL;

		krb5_free_keytab_entry_contents (k5, &entry);

		if (code != 0)

			return code;

	}

	return 0;

}

krb5_error_code

_adcli_krb5_keytab_add_entries (krb5_context k5,

                                krb5_keytab keytab,

                                krb5_principal principal,

                                krb5_kvno kvno,

                                krb5_data *password,

                                krb5_enctype *enctypes,

                                krb5_data *salt)

{

	krb5_keytab_entry entry;

	krb5_error_code code;

	int i;

	for (i = 0; enctypes[i] != 0; i++) {

		memset (&entry, 0, sizeof(entry));

		code = krb5_c_string_to_key (k5, enctypes[i], password, salt, &entry.key);

		if (code != 0)

			return code;

		entry.principal = principal;

		entry.vno = kvno;

		code = krb5_kt_add_entry (k5, keytab, &entry);

		entry.principal = NULL;

		krb5_free_keytab_entry_contents (k5, &entry);

		if (code != 0)

			return code;

	}

	return 0;

}

krb5_error_code

_adcli_krb5_keytab_test_salt (krb5_context k5,

                              krb5_keytab scratch,

                              krb5_principal principal,

                              krb5_kvno kvno,

                              krb5_data *password,

                              krb5_enctype *enctypes,

                              krb5_data *salt)

{

	krb5_error_code code;

	krb5_creds creds;

	code = _adcli_krb5_keytab_clear_all (k5, scratch);

	return_val_if_fail (code == 0, code);

	code = _adcli_krb5_keytab_add_entries (k5, scratch, principal, kvno,

	                                       password, enctypes, salt);

	return_val_if_fail (code == 0, code);

	memset(&creds, 0, sizeof (creds));

	code = krb5_get_init_creds_keytab (k5, &creds, principal, scratch, 0, NULL, NULL);

	krb5_free_cred_contents (k5, &creds);

	return code;

}

krb5_error_code

_adcli_krb5_keytab_discover_salt (krb5_context k5,

                                  krb5_principal principal,

                                  krb5_kvno kvno,

                                  krb5_data *password,

                                  krb5_enctype *enctypes,

                                  krb5_data *salts,

                                  int *discovered)

{

	krb5_keytab scratch;

	krb5_error_code code;

	int i;

	/* TODO: This should be a unique name */

	code = krb5_kt_resolve (k5, "MEMORY:adcli-discover-salt", &scratch);

	return_val_if_fail (code == 0, code);

	for (i = 0; salts[i].data != NULL; i++) {

		code = _adcli_krb5_keytab_test_salt (k5, scratch, principal, kvno,

		                                     password, enctypes, &salts[i]);

		if (code == 0) {

			*discovered = i;

			break;

		} else if (code != KRB5_PREAUTH_FAILED && code != KRB5KDC_ERR_PREAUTH_FAILED) {

			break;

		}

	}

	krb5_kt_close (k5, scratch);

	return code;

}

krb5_error_code

_adcli_krb5_w2k3_salt (krb5_context k5,

                       krb5_principal principal,

                       const char *host_netbios,

                       krb5_data *salt)

{

	krb5_data *realm;

	size_t size = 0;

	size_t host_length = 0;

	size_t at = 0;

	int i;

	/*

	 * The format for the w2k3 computer account salt is:

	 * REALM | "host" | SAM-Account-Name-Without-$ | "." | realm

	 */

	realm = krb5_princ_realm (k5, principal);

	host_length = strlen (host_netbios);

	size += realm->length;

	size += 4; /* "host" */

	size += host_length;

	size += 1; /* "." */

	size += realm->length;

	salt->data = malloc (size);

	return_val_if_fail (salt->data != NULL, ENOMEM);

	/* Upper case realm */

	for (i = 0; i < realm->length; i++)

		salt->data[at + i] = toupper (realm->data[i]);

	at += realm->length;

	/* The string "host" */

	memcpy (salt->data + at, "host", 4);

	at += 4;

	/* The netbios name in lower case */

	for (i = 0; i < host_length; i++)

		salt->data[at + i] = tolower (host_netbios[i]);

	at += host_length;

	/* The dot */

	memcpy (salt->data + at, ".", 1);

	at += 1;

	/* Lower case realm */

	for (i = 0; i < realm->length; i++)

		salt->data[at + i] = tolower (realm->data[i]);

	at += realm->length;

	assert (at == size);

	salt->length = size;

	return 0;

}

/* for msDs-supportedEncryptionTypes  bit defines */

#define MS_KERB_ENCTYPE_DES_CBC_CRC             0x01

#define MS_KERB_ENCTYPE_DES_CBC_MD5             0x02

#define MS_KERB_ENCTYPE_RC4_HMAC_MD5            0x04

#define MS_KERB_ENCTYPE_AES128_CTC_HMAC_SHA1_96 0x08

#define MS_KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96 0x10

krb5_enctype *

_adcli_krb5_parse_enctypes (const char *value)

{

	const int max_enctypes = 5;

	char *end = NULL;

	krb5_enctype *enctypes;

	int types;

	int at;

	types = strtoul (value, &end, 10);

	if (end == NULL || *end != '\0')

		return NULL;

	enctypes = calloc (max_enctypes + 1, sizeof (krb5_enctype));

	return_val_if_fail (enctypes != NULL, NULL);

	at = 0;

	if (types & MS_KERB_ENCTYPE_DES_CBC_CRC)

		enctypes[at++] = ENCTYPE_DES_CBC_CRC;

	if (types & MS_KERB_ENCTYPE_DES_CBC_MD5)

		enctypes[at++] = ENCTYPE_DES_CBC_MD5;

	if (types & MS_KERB_ENCTYPE_RC4_HMAC_MD5)

		enctypes[at++] = ENCTYPE_ARCFOUR_HMAC;

	if (types & MS_KERB_ENCTYPE_AES128_CTC_HMAC_SHA1_96)

		enctypes[at++] = ENCTYPE_AES128_CTS_HMAC_SHA1_96;

	if (types & MS_KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96)

		enctypes[at++] = ENCTYPE_AES256_CTS_HMAC_SHA1_96;

	assert (at <= max_enctypes);

	enctypes[at] = 0;

	return enctypes;

}

char *

_adcli_krb5_format_enctypes (krb5_enctype *enctypes)

{

	char *value;

	int types;

	int i;

	types = 0;

	for (i = 0; enctypes[i] != 0; i++) {

		switch (enctypes[i]) {

		case ENCTYPE_DES_CBC_CRC:

			types |= MS_KERB_ENCTYPE_DES_CBC_CRC;

			break;

		case ENCTYPE_DES_CBC_MD5:

			types |= MS_KERB_ENCTYPE_DES_CBC_MD5;

			break;

		case ENCTYPE_ARCFOUR_HMAC:

			types |= MS_KERB_ENCTYPE_RC4_HMAC_MD5;

			break;

		case ENCTYPE_AES128_CTS_HMAC_SHA1_96:

			types |= MS_KERB_ENCTYPE_AES128_CTC_HMAC_SHA1_96;

			break;

		case ENCTYPE_AES256_CTS_HMAC_SHA1_96:

			types |= MS_KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96;

			break;

		default:

			break;

		}

	}

	if (types == 0)

		return NULL;

	if (asprintf (&value, "%d", types) < 0)

		return_val_if_reached (NULL);

	return value;

}