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      1 /*
      2  * TLSv1 server (RFC 2246)
      3  * Copyright (c) 2006-2007, Jouni Malinen <j (at) w1.fi>
      4  *
      5  * This program is free software; you can redistribute it and/or modify
      6  * it under the terms of the GNU General Public License version 2 as
      7  * published by the Free Software Foundation.
      8  *
      9  * Alternatively, this software may be distributed under the terms of BSD
     10  * license.
     11  *
     12  * See README and COPYING for more details.
     13  */
     14 
     15 #include "includes.h"
     16 
     17 #include "common.h"
     18 #include "crypto/sha1.h"
     19 #include "crypto/tls.h"
     20 #include "tlsv1_common.h"
     21 #include "tlsv1_record.h"
     22 #include "tlsv1_server.h"
     23 #include "tlsv1_server_i.h"
     24 
     25 /* TODO:
     26  * Support for a message fragmented across several records (RFC 2246, 6.2.1)
     27  */
     28 
     29 
     30 void tlsv1_server_alert(struct tlsv1_server *conn, u8 level, u8 description)
     31 {
     32 	conn->alert_level = level;
     33 	conn->alert_description = description;
     34 }
     35 
     36 
     37 int tlsv1_server_derive_keys(struct tlsv1_server *conn,
     38 			     const u8 *pre_master_secret,
     39 			     size_t pre_master_secret_len)
     40 {
     41 	u8 seed[2 * TLS_RANDOM_LEN];
     42 	u8 key_block[TLS_MAX_KEY_BLOCK_LEN];
     43 	u8 *pos;
     44 	size_t key_block_len;
     45 
     46 	if (pre_master_secret) {
     47 		wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: pre_master_secret",
     48 				pre_master_secret, pre_master_secret_len);
     49 		os_memcpy(seed, conn->client_random, TLS_RANDOM_LEN);
     50 		os_memcpy(seed + TLS_RANDOM_LEN, conn->server_random,
     51 			  TLS_RANDOM_LEN);
     52 		if (tls_prf(pre_master_secret, pre_master_secret_len,
     53 			    "master secret", seed, 2 * TLS_RANDOM_LEN,
     54 			    conn->master_secret, TLS_MASTER_SECRET_LEN)) {
     55 			wpa_printf(MSG_DEBUG, "TLSv1: Failed to derive "
     56 				   "master_secret");
     57 			return -1;
     58 		}
     59 		wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: master_secret",
     60 				conn->master_secret, TLS_MASTER_SECRET_LEN);
     61 	}
     62 
     63 	os_memcpy(seed, conn->server_random, TLS_RANDOM_LEN);
     64 	os_memcpy(seed + TLS_RANDOM_LEN, conn->client_random, TLS_RANDOM_LEN);
     65 	key_block_len = 2 * (conn->rl.hash_size + conn->rl.key_material_len +
     66 			     conn->rl.iv_size);
     67 	if (tls_prf(conn->master_secret, TLS_MASTER_SECRET_LEN,
     68 		    "key expansion", seed, 2 * TLS_RANDOM_LEN,
     69 		    key_block, key_block_len)) {
     70 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to derive key_block");
     71 		return -1;
     72 	}
     73 	wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: key_block",
     74 			key_block, key_block_len);
     75 
     76 	pos = key_block;
     77 
     78 	/* client_write_MAC_secret */
     79 	os_memcpy(conn->rl.read_mac_secret, pos, conn->rl.hash_size);
     80 	pos += conn->rl.hash_size;
     81 	/* server_write_MAC_secret */
     82 	os_memcpy(conn->rl.write_mac_secret, pos, conn->rl.hash_size);
     83 	pos += conn->rl.hash_size;
     84 
     85 	/* client_write_key */
     86 	os_memcpy(conn->rl.read_key, pos, conn->rl.key_material_len);
     87 	pos += conn->rl.key_material_len;
     88 	/* server_write_key */
     89 	os_memcpy(conn->rl.write_key, pos, conn->rl.key_material_len);
     90 	pos += conn->rl.key_material_len;
     91 
     92 	/* client_write_IV */
     93 	os_memcpy(conn->rl.read_iv, pos, conn->rl.iv_size);
     94 	pos += conn->rl.iv_size;
     95 	/* server_write_IV */
     96 	os_memcpy(conn->rl.write_iv, pos, conn->rl.iv_size);
     97 	pos += conn->rl.iv_size;
     98 
     99 	return 0;
    100 }
    101 
    102 
    103 /**
    104  * tlsv1_server_handshake - Process TLS handshake
    105  * @conn: TLSv1 server connection data from tlsv1_server_init()
    106  * @in_data: Input data from TLS peer
    107  * @in_len: Input data length
    108  * @out_len: Length of the output buffer.
    109  * Returns: Pointer to output data, %NULL on failure
    110  */
    111 u8 * tlsv1_server_handshake(struct tlsv1_server *conn,
    112 			    const u8 *in_data, size_t in_len,
    113 			    size_t *out_len)
    114 {
    115 	const u8 *pos, *end;
    116 	u8 *msg = NULL, *in_msg, *in_pos, *in_end, alert, ct;
    117 	size_t in_msg_len;
    118 
    119 	if (in_data == NULL || in_len == 0) {
    120 		wpa_printf(MSG_DEBUG, "TLSv1: No input data to server");
    121 		return NULL;
    122 	}
    123 
    124 	pos = in_data;
    125 	end = in_data + in_len;
    126 	in_msg = os_malloc(in_len);
    127 	if (in_msg == NULL)
    128 		return NULL;
    129 
    130 	/* Each received packet may include multiple records */
    131 	while (pos < end) {
    132 		in_msg_len = in_len;
    133 		if (tlsv1_record_receive(&conn->rl, pos, end - pos,
    134 					 in_msg, &in_msg_len, &alert)) {
    135 			wpa_printf(MSG_DEBUG, "TLSv1: Processing received "
    136 				   "record failed");
    137 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL, alert);
    138 			goto failed;
    139 		}
    140 		ct = pos[0];
    141 
    142 		in_pos = in_msg;
    143 		in_end = in_msg + in_msg_len;
    144 
    145 		/* Each received record may include multiple messages of the
    146 		 * same ContentType. */
    147 		while (in_pos < in_end) {
    148 			in_msg_len = in_end - in_pos;
    149 			if (tlsv1_server_process_handshake(conn, ct, in_pos,
    150 							   &in_msg_len) < 0)
    151 				goto failed;
    152 			in_pos += in_msg_len;
    153 		}
    154 
    155 		pos += TLS_RECORD_HEADER_LEN + WPA_GET_BE16(pos + 3);
    156 	}
    157 
    158 	os_free(in_msg);
    159 	in_msg = NULL;
    160 
    161 	msg = tlsv1_server_handshake_write(conn, out_len);
    162 
    163 failed:
    164 	os_free(in_msg);
    165 	if (conn->alert_level) {
    166 		if (conn->state == FAILED) {
    167 			/* Avoid alert loops */
    168 			wpa_printf(MSG_DEBUG, "TLSv1: Drop alert loop");
    169 			os_free(msg);
    170 			return NULL;
    171 		}
    172 		conn->state = FAILED;
    173 		os_free(msg);
    174 		msg = tlsv1_server_send_alert(conn, conn->alert_level,
    175 					      conn->alert_description,
    176 					      out_len);
    177 	}
    178 
    179 	return msg;
    180 }
    181 
    182 
    183 /**
    184  * tlsv1_server_encrypt - Encrypt data into TLS tunnel
    185  * @conn: TLSv1 server connection data from tlsv1_server_init()
    186  * @in_data: Pointer to plaintext data to be encrypted
    187  * @in_len: Input buffer length
    188  * @out_data: Pointer to output buffer (encrypted TLS data)
    189  * @out_len: Maximum out_data length
    190  * Returns: Number of bytes written to out_data, -1 on failure
    191  *
    192  * This function is used after TLS handshake has been completed successfully to
    193  * send data in the encrypted tunnel.
    194  */
    195 int tlsv1_server_encrypt(struct tlsv1_server *conn,
    196 			 const u8 *in_data, size_t in_len,
    197 			 u8 *out_data, size_t out_len)
    198 {
    199 	size_t rlen;
    200 
    201 	wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: Plaintext AppData",
    202 			in_data, in_len);
    203 
    204 	os_memcpy(out_data + TLS_RECORD_HEADER_LEN, in_data, in_len);
    205 
    206 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_APPLICATION_DATA,
    207 			      out_data, out_len, in_len, &rlen) < 0) {
    208 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
    209 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
    210 				   TLS_ALERT_INTERNAL_ERROR);
    211 		return -1;
    212 	}
    213 
    214 	return rlen;
    215 }
    216 
    217 
    218 /**
    219  * tlsv1_server_decrypt - Decrypt data from TLS tunnel
    220  * @conn: TLSv1 server connection data from tlsv1_server_init()
    221  * @in_data: Pointer to input buffer (encrypted TLS data)
    222  * @in_len: Input buffer length
    223  * @out_data: Pointer to output buffer (decrypted data from TLS tunnel)
    224  * @out_len: Maximum out_data length
    225  * Returns: Number of bytes written to out_data, -1 on failure
    226  *
    227  * This function is used after TLS handshake has been completed successfully to
    228  * receive data from the encrypted tunnel.
    229  */
    230 int tlsv1_server_decrypt(struct tlsv1_server *conn,
    231 			 const u8 *in_data, size_t in_len,
    232 			 u8 *out_data, size_t out_len)
    233 {
    234 	const u8 *in_end, *pos;
    235 	int res;
    236 	u8 alert, *out_end, *out_pos;
    237 	size_t olen;
    238 
    239 	pos = in_data;
    240 	in_end = in_data + in_len;
    241 	out_pos = out_data;
    242 	out_end = out_data + out_len;
    243 
    244 	while (pos < in_end) {
    245 		if (pos[0] != TLS_CONTENT_TYPE_APPLICATION_DATA) {
    246 			wpa_printf(MSG_DEBUG, "TLSv1: Unexpected content type "
    247 				   "0x%x", pos[0]);
    248 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
    249 					   TLS_ALERT_UNEXPECTED_MESSAGE);
    250 			return -1;
    251 		}
    252 
    253 		olen = out_end - out_pos;
    254 		res = tlsv1_record_receive(&conn->rl, pos, in_end - pos,
    255 					   out_pos, &olen, &alert);
    256 		if (res < 0) {
    257 			wpa_printf(MSG_DEBUG, "TLSv1: Record layer processing "
    258 				   "failed");
    259 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL, alert);
    260 			return -1;
    261 		}
    262 		out_pos += olen;
    263 		if (out_pos > out_end) {
    264 			wpa_printf(MSG_DEBUG, "TLSv1: Buffer not large enough "
    265 				   "for processing the received record");
    266 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
    267 					   TLS_ALERT_INTERNAL_ERROR);
    268 			return -1;
    269 		}
    270 
    271 		pos += TLS_RECORD_HEADER_LEN + WPA_GET_BE16(pos + 3);
    272 	}
    273 
    274 	return out_pos - out_data;
    275 }
    276 
    277 
    278 /**
    279  * tlsv1_server_global_init - Initialize TLSv1 server
    280  * Returns: 0 on success, -1 on failure
    281  *
    282  * This function must be called before using any other TLSv1 server functions.
    283  */
    284 int tlsv1_server_global_init(void)
    285 {
    286 	return crypto_global_init();
    287 }
    288 
    289 
    290 /**
    291  * tlsv1_server_global_deinit - Deinitialize TLSv1 server
    292  *
    293  * This function can be used to deinitialize the TLSv1 server that was
    294  * initialized by calling tlsv1_server_global_init(). No TLSv1 server functions
    295  * can be called after this before calling tlsv1_server_global_init() again.
    296  */
    297 void tlsv1_server_global_deinit(void)
    298 {
    299 	crypto_global_deinit();
    300 }
    301 
    302 
    303 /**
    304  * tlsv1_server_init - Initialize TLSv1 server connection
    305  * @cred: Pointer to server credentials from tlsv1_server_cred_alloc()
    306  * Returns: Pointer to TLSv1 server connection data or %NULL on failure
    307  */
    308 struct tlsv1_server * tlsv1_server_init(struct tlsv1_credentials *cred)
    309 {
    310 	struct tlsv1_server *conn;
    311 	size_t count;
    312 	u16 *suites;
    313 
    314 	conn = os_zalloc(sizeof(*conn));
    315 	if (conn == NULL)
    316 		return NULL;
    317 
    318 	conn->cred = cred;
    319 
    320 	conn->state = CLIENT_HELLO;
    321 
    322 	if (tls_verify_hash_init(&conn->verify) < 0) {
    323 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to initialize verify "
    324 			   "hash");
    325 		os_free(conn);
    326 		return NULL;
    327 	}
    328 
    329 	count = 0;
    330 	suites = conn->cipher_suites;
    331 #ifndef CONFIG_CRYPTO_INTERNAL
    332 	suites[count++] = TLS_RSA_WITH_AES_256_CBC_SHA;
    333 #endif /* CONFIG_CRYPTO_INTERNAL */
    334 	suites[count++] = TLS_RSA_WITH_AES_128_CBC_SHA;
    335 	suites[count++] = TLS_RSA_WITH_3DES_EDE_CBC_SHA;
    336 	suites[count++] = TLS_RSA_WITH_RC4_128_SHA;
    337 	suites[count++] = TLS_RSA_WITH_RC4_128_MD5;
    338 	conn->num_cipher_suites = count;
    339 
    340 	return conn;
    341 }
    342 
    343 
    344 static void tlsv1_server_clear_data(struct tlsv1_server *conn)
    345 {
    346 	tlsv1_record_set_cipher_suite(&conn->rl, TLS_NULL_WITH_NULL_NULL);
    347 	tlsv1_record_change_write_cipher(&conn->rl);
    348 	tlsv1_record_change_read_cipher(&conn->rl);
    349 	tls_verify_hash_free(&conn->verify);
    350 
    351 	crypto_public_key_free(conn->client_rsa_key);
    352 	conn->client_rsa_key = NULL;
    353 
    354 	os_free(conn->session_ticket);
    355 	conn->session_ticket = NULL;
    356 	conn->session_ticket_len = 0;
    357 	conn->use_session_ticket = 0;
    358 
    359 	os_free(conn->dh_secret);
    360 	conn->dh_secret = NULL;
    361 	conn->dh_secret_len = 0;
    362 }
    363 
    364 
    365 /**
    366  * tlsv1_server_deinit - Deinitialize TLSv1 server connection
    367  * @conn: TLSv1 server connection data from tlsv1_server_init()
    368  */
    369 void tlsv1_server_deinit(struct tlsv1_server *conn)
    370 {
    371 	tlsv1_server_clear_data(conn);
    372 	os_free(conn);
    373 }
    374 
    375 
    376 /**
    377  * tlsv1_server_established - Check whether connection has been established
    378  * @conn: TLSv1 server connection data from tlsv1_server_init()
    379  * Returns: 1 if connection is established, 0 if not
    380  */
    381 int tlsv1_server_established(struct tlsv1_server *conn)
    382 {
    383 	return conn->state == ESTABLISHED;
    384 }
    385 
    386 
    387 /**
    388  * tlsv1_server_prf - Use TLS-PRF to derive keying material
    389  * @conn: TLSv1 server connection data from tlsv1_server_init()
    390  * @label: Label (e.g., description of the key) for PRF
    391  * @server_random_first: seed is 0 = client_random|server_random,
    392  * 1 = server_random|client_random
    393  * @out: Buffer for output data from TLS-PRF
    394  * @out_len: Length of the output buffer
    395  * Returns: 0 on success, -1 on failure
    396  */
    397 int tlsv1_server_prf(struct tlsv1_server *conn, const char *label,
    398 		     int server_random_first, u8 *out, size_t out_len)
    399 {
    400 	u8 seed[2 * TLS_RANDOM_LEN];
    401 
    402 	if (conn->state != ESTABLISHED)
    403 		return -1;
    404 
    405 	if (server_random_first) {
    406 		os_memcpy(seed, conn->server_random, TLS_RANDOM_LEN);
    407 		os_memcpy(seed + TLS_RANDOM_LEN, conn->client_random,
    408 			  TLS_RANDOM_LEN);
    409 	} else {
    410 		os_memcpy(seed, conn->client_random, TLS_RANDOM_LEN);
    411 		os_memcpy(seed + TLS_RANDOM_LEN, conn->server_random,
    412 			  TLS_RANDOM_LEN);
    413 	}
    414 
    415 	return tls_prf(conn->master_secret, TLS_MASTER_SECRET_LEN,
    416 		       label, seed, 2 * TLS_RANDOM_LEN, out, out_len);
    417 }
    418 
    419 
    420 /**
    421  * tlsv1_server_get_cipher - Get current cipher name
    422  * @conn: TLSv1 server connection data from tlsv1_server_init()
    423  * @buf: Buffer for the cipher name
    424  * @buflen: buf size
    425  * Returns: 0 on success, -1 on failure
    426  *
    427  * Get the name of the currently used cipher.
    428  */
    429 int tlsv1_server_get_cipher(struct tlsv1_server *conn, char *buf,
    430 			    size_t buflen)
    431 {
    432 	char *cipher;
    433 
    434 	switch (conn->rl.cipher_suite) {
    435 	case TLS_RSA_WITH_RC4_128_MD5:
    436 		cipher = "RC4-MD5";
    437 		break;
    438 	case TLS_RSA_WITH_RC4_128_SHA:
    439 		cipher = "RC4-SHA";
    440 		break;
    441 	case TLS_RSA_WITH_DES_CBC_SHA:
    442 		cipher = "DES-CBC-SHA";
    443 		break;
    444 	case TLS_RSA_WITH_3DES_EDE_CBC_SHA:
    445 		cipher = "DES-CBC3-SHA";
    446 		break;
    447 	case TLS_DH_anon_WITH_AES_128_CBC_SHA:
    448 		cipher = "ADH-AES-128-SHA";
    449 		break;
    450 	case TLS_RSA_WITH_AES_256_CBC_SHA:
    451 		cipher = "AES-256-SHA";
    452 		break;
    453 	case TLS_RSA_WITH_AES_128_CBC_SHA:
    454 		cipher = "AES-128-SHA";
    455 		break;
    456 	default:
    457 		return -1;
    458 	}
    459 
    460 	if (os_strlcpy(buf, cipher, buflen) >= buflen)
    461 		return -1;
    462 	return 0;
    463 }
    464 
    465 
    466 /**
    467  * tlsv1_server_shutdown - Shutdown TLS connection
    468  * @conn: TLSv1 server connection data from tlsv1_server_init()
    469  * Returns: 0 on success, -1 on failure
    470  */
    471 int tlsv1_server_shutdown(struct tlsv1_server *conn)
    472 {
    473 	conn->state = CLIENT_HELLO;
    474 
    475 	if (tls_verify_hash_init(&conn->verify) < 0) {
    476 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to re-initialize verify "
    477 			   "hash");
    478 		return -1;
    479 	}
    480 
    481 	tlsv1_server_clear_data(conn);
    482 
    483 	return 0;
    484 }
    485 
    486 
    487 /**
    488  * tlsv1_server_resumed - Was session resumption used
    489  * @conn: TLSv1 server connection data from tlsv1_server_init()
    490  * Returns: 1 if current session used session resumption, 0 if not
    491  */
    492 int tlsv1_server_resumed(struct tlsv1_server *conn)
    493 {
    494 	return 0;
    495 }
    496 
    497 
    498 /**
    499  * tlsv1_server_get_keys - Get master key and random data from TLS connection
    500  * @conn: TLSv1 server connection data from tlsv1_server_init()
    501  * @keys: Structure of key/random data (filled on success)
    502  * Returns: 0 on success, -1 on failure
    503  */
    504 int tlsv1_server_get_keys(struct tlsv1_server *conn, struct tls_keys *keys)
    505 {
    506 	os_memset(keys, 0, sizeof(*keys));
    507 	if (conn->state == CLIENT_HELLO)
    508 		return -1;
    509 
    510 	keys->client_random = conn->client_random;
    511 	keys->client_random_len = TLS_RANDOM_LEN;
    512 
    513 	if (conn->state != SERVER_HELLO) {
    514 		keys->server_random = conn->server_random;
    515 		keys->server_random_len = TLS_RANDOM_LEN;
    516 		keys->master_key = conn->master_secret;
    517 		keys->master_key_len = TLS_MASTER_SECRET_LEN;
    518 	}
    519 
    520 	return 0;
    521 }
    522 
    523 
    524 /**
    525  * tlsv1_server_get_keyblock_size - Get TLS key_block size
    526  * @conn: TLSv1 server connection data from tlsv1_server_init()
    527  * Returns: Size of the key_block for the negotiated cipher suite or -1 on
    528  * failure
    529  */
    530 int tlsv1_server_get_keyblock_size(struct tlsv1_server *conn)
    531 {
    532 	if (conn->state == CLIENT_HELLO || conn->state == SERVER_HELLO)
    533 		return -1;
    534 
    535 	return 2 * (conn->rl.hash_size + conn->rl.key_material_len +
    536 		    conn->rl.iv_size);
    537 }
    538 
    539 
    540 /**
    541  * tlsv1_server_set_cipher_list - Configure acceptable cipher suites
    542  * @conn: TLSv1 server connection data from tlsv1_server_init()
    543  * @ciphers: Zero (TLS_CIPHER_NONE) terminated list of allowed ciphers
    544  * (TLS_CIPHER_*).
    545  * Returns: 0 on success, -1 on failure
    546  */
    547 int tlsv1_server_set_cipher_list(struct tlsv1_server *conn, u8 *ciphers)
    548 {
    549 	size_t count;
    550 	u16 *suites;
    551 
    552 	/* TODO: implement proper configuration of cipher suites */
    553 	if (ciphers[0] == TLS_CIPHER_ANON_DH_AES128_SHA) {
    554 		count = 0;
    555 		suites = conn->cipher_suites;
    556 #ifndef CONFIG_CRYPTO_INTERNAL
    557 		suites[count++] = TLS_RSA_WITH_AES_256_CBC_SHA;
    558 #endif /* CONFIG_CRYPTO_INTERNAL */
    559 		suites[count++] = TLS_RSA_WITH_AES_128_CBC_SHA;
    560 		suites[count++] = TLS_RSA_WITH_3DES_EDE_CBC_SHA;
    561 		suites[count++] = TLS_RSA_WITH_RC4_128_SHA;
    562 		suites[count++] = TLS_RSA_WITH_RC4_128_MD5;
    563 #ifndef CONFIG_CRYPTO_INTERNAL
    564 		suites[count++] = TLS_DH_anon_WITH_AES_256_CBC_SHA;
    565 #endif /* CONFIG_CRYPTO_INTERNAL */
    566 		suites[count++] = TLS_DH_anon_WITH_AES_128_CBC_SHA;
    567 		suites[count++] = TLS_DH_anon_WITH_3DES_EDE_CBC_SHA;
    568 		suites[count++] = TLS_DH_anon_WITH_RC4_128_MD5;
    569 		suites[count++] = TLS_DH_anon_WITH_DES_CBC_SHA;
    570 		conn->num_cipher_suites = count;
    571 	}
    572 
    573 	return 0;
    574 }
    575 
    576 
    577 int tlsv1_server_set_verify(struct tlsv1_server *conn, int verify_peer)
    578 {
    579 	conn->verify_peer = verify_peer;
    580 	return 0;
    581 }
    582 
    583 
    584 void tlsv1_server_set_session_ticket_cb(struct tlsv1_server *conn,
    585 					tlsv1_server_session_ticket_cb cb,
    586 					void *ctx)
    587 {
    588 	wpa_printf(MSG_DEBUG, "TLSv1: SessionTicket callback set %p (ctx %p)",
    589 		   cb, ctx);
    590 	conn->session_ticket_cb = cb;
    591 	conn->session_ticket_cb_ctx = ctx;
    592 }
    593