text: /*
   * EAP peer: EAP-TLS/PEAP/TTLS/FAST common functions
   * Copyright (c) 2004-2019, Jouni Malinen <j@w1.fi>
   *
   * This software may be distributed under the terms of the BSD license.
   * See README for more details.
   */
  
  #include "includes.h"
  
  #include "common.h"
  #include "crypto/sha1.h"
  #include "crypto/tls.h"
  #include "eap_i.h"
  #include "eap_tls_common.h"
  #include "eap_config.h"
  
  
  static struct wpabuf * eap_tls_msg_alloc(enum eap_type type, size_t payload_len,
  					 u8 code, u8 identifier)
  {
  	if (type == EAP_UNAUTH_TLS_TYPE)
  		return eap_msg_alloc(EAP_VENDOR_UNAUTH_TLS,
  				     EAP_VENDOR_TYPE_UNAUTH_TLS, payload_len,
  				     code, identifier);
  	if (type == EAP_WFA_UNAUTH_TLS_TYPE)
  		return eap_msg_alloc(EAP_VENDOR_WFA_NEW,
  				     EAP_VENDOR_WFA_UNAUTH_TLS, payload_len,
  				     code, identifier);
  	return eap_msg_alloc(EAP_VENDOR_IETF, type, payload_len, code,
  			     identifier);
  }
  
  
  static int eap_tls_check_blob(struct eap_sm *sm, const char **name,
  			      const u8 **data, size_t *data_len)
  {
  	const struct wpa_config_blob *blob;
  
  	if (*name == NULL || os_strncmp(*name, "blob://", 7) != 0)
  		return 0;
  
  	blob = eap_get_config_blob(sm, *name + 7);
  	if (blob == NULL) {
  		wpa_printf(MSG_ERROR, "%s: Named configuration blob '%s' not "
  			   "found", __func__, *name + 7);
  		return -1;
  	}
  
  	*name = NULL;
  	*data = blob->data;
  	*data_len = blob->len;
  
  	return 0;
  }
  
  
  static void eap_tls_params_flags(struct tls_connection_params *params,
  				 const char *txt)
  {
  	if (txt == NULL)
  		return;
  	if (os_strstr(txt, "tls_allow_md5=1"))
  		params->flags |= TLS_CONN_ALLOW_SIGN_RSA_MD5;
  	if (os_strstr(txt, "tls_disable_time_checks=1"))
  		params->flags |= TLS_CONN_DISABLE_TIME_CHECKS;
  	if (os_strstr(txt, "tls_disable_session_ticket=1"))
  		params->flags |= TLS_CONN_DISABLE_SESSION_TICKET;
  	if (os_strstr(txt, "tls_disable_session_ticket=0"))
  		params->flags &= ~TLS_CONN_DISABLE_SESSION_TICKET;
  	if (os_strstr(txt, "tls_disable_tlsv1_0=1"))
  		params->flags |= TLS_CONN_DISABLE_TLSv1_0;
  	if (os_strstr(txt, "tls_disable_tlsv1_0=0")) {
  		params->flags &= ~TLS_CONN_DISABLE_TLSv1_0;
  		params->flags |= TLS_CONN_ENABLE_TLSv1_0;
  	}
  	if (os_strstr(txt, "tls_disable_tlsv1_1=1"))
  		params->flags |= TLS_CONN_DISABLE_TLSv1_1;
  	if (os_strstr(txt, "tls_disable_tlsv1_1=0")) {
  		params->flags &= ~TLS_CONN_DISABLE_TLSv1_1;
  		params->flags |= TLS_CONN_ENABLE_TLSv1_1;
  	}
  	if (os_strstr(txt, "tls_disable_tlsv1_2=1"))
  		params->flags |= TLS_CONN_DISABLE_TLSv1_2;
  	if (os_strstr(txt, "tls_disable_tlsv1_2=0")) {
  		params->flags &= ~TLS_CONN_DISABLE_TLSv1_2;
  		params->flags |= TLS_CONN_ENABLE_TLSv1_2;
  	}
  	if (os_strstr(txt, "tls_disable_tlsv1_3=1"))
  		params->flags |= TLS_CONN_DISABLE_TLSv1_3;
  	if (os_strstr(txt, "tls_disable_tlsv1_3=0"))
  		params->flags &= ~TLS_CONN_DISABLE_TLSv1_3;
  	if (os_strstr(txt, "tls_ext_cert_check=1"))
  		params->flags |= TLS_CONN_EXT_CERT_CHECK;
  	if (os_strstr(txt, "tls_ext_cert_check=0"))
  		params->flags &= ~TLS_CONN_EXT_CERT_CHECK;
  	if (os_strstr(txt, "tls_suiteb=1"))
  		params->flags |= TLS_CONN_SUITEB;
  	if (os_strstr(txt, "tls_suiteb=0"))
  		params->flags &= ~TLS_CONN_SUITEB;
  	if (os_strstr(txt, "tls_suiteb_no_ecdh=1"))
  		params->flags |= TLS_CONN_SUITEB_NO_ECDH;
  	if (os_strstr(txt, "tls_suiteb_no_ecdh=0"))
  		params->flags &= ~TLS_CONN_SUITEB_NO_ECDH;
  }
  
  
  static void eap_tls_cert_params_from_conf(struct tls_connection_params *params,
  					  struct eap_peer_cert_config *config)
  {
  	params->ca_cert = config->ca_cert;
  	params->ca_path = config->ca_path;
  	params->client_cert = config->client_cert;
  	params->private_key = config->private_key;
  	params->private_key_passwd = config->private_key_passwd;
  	params->dh_file = config->dh_file;
  	params->subject_match = config->subject_match;
  	params->altsubject_match = config->altsubject_match;
  	params->check_cert_subject = config->check_cert_subject;
  	params->suffix_match = config->domain_suffix_match;
  	params->domain_match = config->domain_match;
  	params->engine = config->engine;
  	params->engine_id = config->engine_id;
  	params->pin = config->pin;
  	params->key_id = config->key_id;
  	params->cert_id = config->cert_id;
  	params->ca_cert_id = config->ca_cert_id;
  	if (config->ocsp)
  		params->flags |= TLS_CONN_REQUEST_OCSP;
  	if (config->ocsp >= 2)
  		params->flags |= TLS_CONN_REQUIRE_OCSP;
  	if (config->ocsp == 3)
  		params->flags |= TLS_CONN_REQUIRE_OCSP_ALL;
  }
  
  
  static void eap_tls_params_from_conf1(struct tls_connection_params *params,
  				      struct eap_peer_config *config)
  {
  	eap_tls_cert_params_from_conf(params, &config->cert);
  	eap_tls_params_flags(params, config->phase1);
  }
  
  
  static void eap_tls_params_from_conf2(struct tls_connection_params *params,
  				      struct eap_peer_config *config)
  {
  	eap_tls_cert_params_from_conf(params, &config->phase2_cert);
  	eap_tls_params_flags(params, config->phase2);
  }
  
  
  static void eap_tls_params_from_conf2m(struct tls_connection_params *params,
  				       struct eap_peer_config *config)
  {
  	eap_tls_cert_params_from_conf(params, &config->machine_cert);
  	eap_tls_params_flags(params, config->machine_phase2);
  }
  
  
  static int eap_tls_params_from_conf(struct eap_sm *sm,
  				    struct eap_ssl_data *data,
  				    struct tls_connection_params *params,
  				    struct eap_peer_config *config, int phase2)
  {
  	os_memset(params, 0, sizeof(*params));
  	if (sm->workaround && data->eap_type != EAP_TYPE_FAST &&
  	    data->eap_type != EAP_TYPE_TEAP) {
  		/*
  		 * Some deployed authentication servers seem to be unable to
  		 * handle the TLS Session Ticket extension (they are supposed
  		 * to ignore unrecognized TLS extensions, but end up rejecting
  		 * the ClientHello instead). As a workaround, disable use of
  		 * TLS Sesson Ticket extension for EAP-TLS, EAP-PEAP, and
  		 * EAP-TTLS (EAP-FAST uses session ticket, so any server that
  		 * supports EAP-FAST does not need this workaround).
  		 */
  		params->flags |= TLS_CONN_DISABLE_SESSION_TICKET;
  	}
  	if (data->eap_type == EAP_TYPE_TEAP) {
  		/* RFC 7170 requires TLS v1.2 or newer to be used with TEAP */
  		params->flags |= TLS_CONN_DISABLE_TLSv1_0 |
  			TLS_CONN_DISABLE_TLSv1_1;
  		if (config->teap_anon_dh)
  			params->flags |= TLS_CONN_TEAP_ANON_DH;
  	}
  	if (data->eap_type == EAP_TYPE_FAST ||
  	    data->eap_type == EAP_TYPE_TEAP ||
  	    data->eap_type == EAP_TYPE_TTLS ||
  	    data->eap_type == EAP_TYPE_PEAP) {
  		/* The current EAP peer implementation is not yet ready for the
  		 * TLS v1.3 changes, so disable this by default for now. */
  		params->flags |= TLS_CONN_DISABLE_TLSv1_3;
  	}
  	if (data->eap_type == EAP_TYPE_TLS ||
  	    data->eap_type == EAP_UNAUTH_TLS_TYPE ||
  	    data->eap_type == EAP_WFA_UNAUTH_TLS_TYPE) {
  		/* While the current EAP-TLS implementation is more or less
  		 * complete for TLS v1.3, there has been no interoperability
  		 * testing with other implementations, so disable for by default
  		 * for now until there has been chance to confirm that no
  		 * significant interoperability issues show up with TLS version
  		 * update.
  		 */
  		params->flags |= TLS_CONN_DISABLE_TLSv1_3;
  	}
  	if (phase2 && sm->use_machine_cred) {
  		wpa_printf(MSG_DEBUG, "TLS: using machine config options");
  		eap_tls_params_from_conf2m(params, config);
  	} else if (phase2) {
  		wpa_printf(MSG_DEBUG, "TLS: using phase2 config options");
  		eap_tls_params_from_conf2(params, config);
  	} else {
  		wpa_printf(MSG_DEBUG, "TLS: using phase1 config options");
  		eap_tls_params_from_conf1(params, config);
  		if (data->eap_type == EAP_TYPE_FAST)
  			params->flags |= TLS_CONN_EAP_FAST;
  	}
  
  	/*
  	 * Use blob data, if available. Otherwise, leave reference to external
  	 * file as-is.
  	 */
  	if (eap_tls_check_blob(sm, &params->ca_cert, &params->ca_cert_blob,
  			       &params->ca_cert_blob_len) ||
  	    eap_tls_check_blob(sm, &params->client_cert,
  			       &params->client_cert_blob,
  			       &params->client_cert_blob_len) ||
  	    eap_tls_check_blob(sm, &params->private_key,
  			       &params->private_key_blob,
  			       &params->private_key_blob_len) ||
  	    eap_tls_check_blob(sm, &params->dh_file, &params->dh_blob,
  			       &params->dh_blob_len)) {
  		wpa_printf(MSG_INFO, "SSL: Failed to get configuration blobs");
  		return -1;
  	}
  
  	params->openssl_ciphers = config->openssl_ciphers;
  	params->openssl_ecdh_curves = config->openssl_ecdh_curves;
  	sm->ext_cert_check = !!(params->flags & TLS_CONN_EXT_CERT_CHECK);
  
  	return 0;
  }
  
  
  static int eap_tls_init_connection(struct eap_sm *sm,
  				   struct eap_ssl_data *data,
  				   struct eap_peer_config *config,
  				   struct tls_connection_params *params)
  {
  	int res;
  
  	data->conn = tls_connection_init(data->ssl_ctx);
  	if (data->conn == NULL) {
  		wpa_printf(MSG_INFO, "SSL: Failed to initialize new TLS "
  			   "connection");
  		return -1;
  	}
  
  	res = tls_connection_set_params(data->ssl_ctx, data->conn, params);
  	if (res == TLS_SET_PARAMS_ENGINE_PRV_BAD_PIN) {
  		/*
  		 * At this point with the pkcs11 engine the PIN is wrong. We
  		 * reset the PIN in the configuration to be sure to not use it
  		 * again and the calling function must request a new one.
  		 */
  		wpa_printf(MSG_INFO,
  			   "TLS: Bad PIN provided, requesting a new one");
  		os_free(config->cert.pin);
  		config->cert.pin = NULL;
  		eap_sm_request_pin(sm);
  		sm->ignore = true;
  	} else if (res == TLS_SET_PARAMS_ENGINE_PRV_INIT_FAILED) {
  		wpa_printf(MSG_INFO, "TLS: Failed to initialize engine");
  	} else if (res == TLS_SET_PARAMS_ENGINE_PRV_VERIFY_FAILED) {
  		wpa_printf(MSG_INFO, "TLS: Failed to load private key");
  		sm->ignore = true;
  	}
  	if (res) {
  		wpa_printf(MSG_INFO, "TLS: Failed to set TLS connection "
  			   "parameters");
  		tls_connection_deinit(data->ssl_ctx, data->conn);
  		data->conn = NULL;
  		return -1;
  	}
  
  	return 0;
  }
  
  
  /**
   * eap_peer_tls_ssl_init - Initialize shared TLS functionality
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @config: Pointer to the network configuration
   * @eap_type: EAP method used in Phase 1 (EAP_TYPE_TLS/PEAP/TTLS/FAST)
   * Returns: 0 on success, -1 on failure
   *
   * This function is used to initialize shared TLS functionality for EAP-TLS,
   * EAP-PEAP, EAP-TTLS, and EAP-FAST.
   */
  int eap_peer_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data,
  			  struct eap_peer_config *config, u8 eap_type)
  {
  	struct tls_connection_params params;
  
  	if (config == NULL)
  		return -1;
  
  	data->eap = sm;
  	data->eap_type = eap_type;
  	data->phase2 = sm->init_phase2;
  	data->ssl_ctx = sm->init_phase2 && sm->ssl_ctx2 ? sm->ssl_ctx2 :
  		sm->ssl_ctx;
  	if (eap_tls_params_from_conf(sm, data, &params, config, data->phase2) <
  	    0)
  		return -1;
  
  	if (eap_tls_init_connection(sm, data, config, &params) < 0)
  		return -1;
  
  	data->tls_out_limit = config->fragment_size;
  	if (data->phase2) {
  		/* Limit the fragment size in the inner TLS authentication
  		 * since the outer authentication with EAP-PEAP does not yet
  		 * support fragmentation */
  		if (data->tls_out_limit > 100)
  			data->tls_out_limit -= 100;
  	}
  
  	if (config->phase1 &&
  	    os_strstr(config->phase1, "include_tls_length=1")) {
  		wpa_printf(MSG_DEBUG, "TLS: Include TLS Message Length in "
  			   "unfragmented packets");
  		data->include_tls_length = 1;
  	}
  
  	return 0;
  }
  
  
  /**
   * eap_peer_tls_ssl_deinit - Deinitialize shared TLS functionality
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   *
   * This function deinitializes shared TLS functionality that was initialized
   * with eap_peer_tls_ssl_init().
   */
  void eap_peer_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data)
  {
  	tls_connection_deinit(data->ssl_ctx, data->conn);
  	eap_peer_tls_reset_input(data);
  	eap_peer_tls_reset_output(data);
  }
  
  
  /**
   * eap_peer_tls_derive_key - Derive a key based on TLS session data
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @label: Label string for deriving the keys, e.g., "client EAP encryption"
   * @context: Optional extra upper-layer context (max len 2^16)
   * @context_len: The length of the context value
   * @len: Length of the key material to generate (usually 64 for MSK)
   * Returns: Pointer to allocated key on success or %NULL on failure
   *
   * This function uses TLS-PRF to generate pseudo-random data based on the TLS
   * session data (client/server random and master key). Each key type may use a
   * different label to bind the key usage into the generated material.
   *
   * The caller is responsible for freeing the returned buffer.
   *
   * Note: To provide the RFC 5705 context, the context variable must be non-NULL.
   */
  u8 * eap_peer_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
  			     const char *label, const u8 *context,
  			     size_t context_len, size_t len)
  {
  	u8 *out;
  
  	out = os_malloc(len);
  	if (out == NULL)
  		return NULL;
  
  	if (tls_connection_export_key(data->ssl_ctx, data->conn, label,
  				      context, context_len, out, len)) {
  		os_free(out);
  		return NULL;
  	}
  
  	return out;
  }
  
  
  /**
   * eap_peer_tls_derive_session_id - Derive a Session-Id based on TLS data
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @eap_type: EAP method used in Phase 1 (EAP_TYPE_TLS/PEAP/TTLS/FAST)
   * @len: Pointer to length of the session ID generated
   * Returns: Pointer to allocated Session-Id on success or %NULL on failure
   *
   * This function derive the Session-Id based on the TLS session data
   * (client/server random and method type).
   *
   * The caller is responsible for freeing the returned buffer.
   */
  u8 * eap_peer_tls_derive_session_id(struct eap_sm *sm,
  				    struct eap_ssl_data *data, u8 eap_type,
  				    size_t *len)
  {
  	struct tls_random keys;
  	u8 *out;
  
  	if (eap_type == EAP_TYPE_TLS && data->tls_v13) {
  		u8 *id, *method_id;
  		const u8 context[] = { EAP_TYPE_TLS };
  
  		/* Session-Id = <EAP-Type> || Method-Id
  		 * Method-Id = TLS-Exporter("EXPORTER_EAP_TLS_Method-Id",
  		 *                          Type-Code, 64)
  		 */
  		*len = 1 + 64;
  		id = os_malloc(*len);
  		if (!id)
  			return NULL;
  		method_id = eap_peer_tls_derive_key(
  			sm, data, "EXPORTER_EAP_TLS_Method-Id", context, 1, 64);
  		if (!method_id) {
  			os_free(id);
  			return NULL;
  		}
  		id[0] = eap_type;
  		os_memcpy(id + 1, method_id, 64);
  		os_free(method_id);
  		return id;
  	}
  
  	if (tls_connection_get_random(sm->ssl_ctx, data->conn, &keys) ||
  	    keys.client_random == NULL || keys.server_random == NULL)
  		return NULL;
  
  	*len = 1 + keys.client_random_len + keys.server_random_len;
  	out = os_malloc(*len);
  	if (out == NULL)
  		return NULL;
  
  	/* Session-Id = EAP type || client.random || server.random */
  	out[0] = eap_type;
  	os_memcpy(out + 1, keys.client_random, keys.client_random_len);
  	os_memcpy(out + 1 + keys.client_random_len, keys.server_random,
  		  keys.server_random_len);
  
  	return out;
  }
  
  
  /**
   * eap_peer_tls_reassemble_fragment - Reassemble a received fragment
   * @data: Data for TLS processing
   * @in_data: Next incoming TLS segment
   * Returns: 0 on success, 1 if more data is needed for the full message, or
   * -1 on error
   */
  static int eap_peer_tls_reassemble_fragment(struct eap_ssl_data *data,
  					    const struct wpabuf *in_data)
  {
  	size_t tls_in_len, in_len;
  
  	tls_in_len = data->tls_in ? wpabuf_len(data->tls_in) : 0;
  	in_len = in_data ? wpabuf_len(in_data) : 0;
  
  	if (tls_in_len + in_len == 0) {
  		/* No message data received?! */
  		wpa_printf(MSG_WARNING, "SSL: Invalid reassembly state: "
  			   "tls_in_left=%lu tls_in_len=%lu in_len=%lu",
  			   (unsigned long) data->tls_in_left,
  			   (unsigned long) tls_in_len,
  			   (unsigned long) in_len);
  		eap_peer_tls_reset_input(data);
  		return -1;
  	}
  
  	if (tls_in_len + in_len > 65536*100) {
  		/*
  		 * Limit length to avoid rogue servers from causing large
  		 * memory allocations.
  		 */
  		wpa_printf(MSG_INFO, "SSL: Too long TLS fragment (size over "
  			   "100*64 kB)");
  		eap_peer_tls_reset_input(data);
  		return -1;
  	}
  
  	if (in_len > data->tls_in_left) {
  		/* Sender is doing something odd - reject message */
  		wpa_printf(MSG_INFO, "SSL: more data than TLS message length "
  			   "indicated");
  		eap_peer_tls_reset_input(data);
  		return -1;
  	}
  
  	if (wpabuf_resize(&data->tls_in, in_len) < 0) {
  		wpa_printf(MSG_INFO, "SSL: Could not allocate memory for TLS "
  			   "data");
  		eap_peer_tls_reset_input(data);
  		return -1;
  	}
  	if (in_data)
  		wpabuf_put_buf(data->tls_in, in_data);
  	data->tls_in_left -= in_len;
  
  	if (data->tls_in_left > 0) {
  		wpa_printf(MSG_DEBUG, "SSL: Need %lu bytes more input "
  			   "data", (unsigned long) data->tls_in_left);
  		return 1;
  	}
  
  	return 0;
  }
  
  
  /**
   * eap_peer_tls_data_reassemble - Reassemble TLS data
   * @data: Data for TLS processing
   * @in_data: Next incoming TLS segment
   * @need_more_input: Variable for returning whether more input data is needed
   * to reassemble this TLS packet
   * Returns: Pointer to output data, %NULL on error or when more data is needed
   * for the full message (in which case, *need_more_input is also set to 1).
   *
   * This function reassembles TLS fragments. Caller must not free the returned
   * data buffer since an internal pointer to it is maintained.
   */
  static const struct wpabuf * eap_peer_tls_data_reassemble(
  	struct eap_ssl_data *data, const struct wpabuf *in_data,
  	int *need_more_input)
  {
  	*need_more_input = 0;
  
  	if (data->tls_in_left > wpabuf_len(in_data) || data->tls_in) {
  		/* Message has fragments */
  		int res = eap_peer_tls_reassemble_fragment(data, in_data);
  		if (res) {
  			if (res == 1)
  				*need_more_input = 1;
  			return NULL;
  		}
  
  		/* Message is now fully reassembled. */
  	} else {
  		/* No fragments in this message, so just make a copy of it. */
  		data->tls_in_left = 0;
  		data->tls_in = wpabuf_dup(in_data);
  		if (data->tls_in == NULL)
  			return NULL;
  	}
  
  	return data->tls_in;
  }
  
  
  /**
   * eap_tls_process_input - Process incoming TLS message
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @in_data: Message received from the server
   * @out_data: Buffer for returning a pointer to application data (if available)
   * Returns: 0 on success, 1 if more input data is needed, 2 if application data
   * is available, -1 on failure
   */
  static int eap_tls_process_input(struct eap_sm *sm, struct eap_ssl_data *data,
  				 const struct wpabuf *in_data,
  				 struct wpabuf **out_data)
  {
  	const struct wpabuf *msg;
  	int need_more_input;
  	struct wpabuf *appl_data;
  
  	msg = eap_peer_tls_data_reassemble(data, in_data, &need_more_input);
  	if (msg == NULL)
  		return need_more_input ? 1 : -1;
  
  	/* Full TLS message reassembled - continue handshake processing */
  	if (data->tls_out) {
  		/* This should not happen.. */
  		wpa_printf(MSG_INFO, "SSL: eap_tls_process_input - pending "
  			   "tls_out data even though tls_out_len = 0");
  		wpabuf_free(data->tls_out);
  		WPA_ASSERT(data->tls_out == NULL);
  	}
  	appl_data = NULL;
  	data->tls_out = tls_connection_handshake(data->ssl_ctx, data->conn,
  						 msg, &appl_data);
  
  	eap_peer_tls_reset_input(data);
  
  	if (appl_data &&
  	    tls_connection_established(data->ssl_ctx, data->conn) &&
  	    !tls_connection_get_failed(data->ssl_ctx, data->conn)) {
  		wpa_hexdump_buf_key(MSG_MSGDUMP, "SSL: Application data",
  				    appl_data);
  		*out_data = appl_data;
  		return 2;
  	}
  
  	wpabuf_free(appl_data);
  
  	return 0;
  }
  
  
  /**
   * eap_tls_process_output - Process outgoing TLS message
   * @data: Data for TLS processing
   * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
   * @peap_version: Version number for EAP-PEAP/TTLS
   * @id: EAP identifier for the response
   * @ret: Return value to use on success
   * @out_data: Buffer for returning the allocated output buffer
   * Returns: ret (0 or 1) on success, -1 on failure
   */
  static int eap_tls_process_output(struct eap_ssl_data *data,
  				  enum eap_type eap_type,
  				  int peap_version, u8 id, int ret,
  				  struct wpabuf **out_data)
  {
  	size_t len;
  	u8 *flags;
  	int more_fragments, length_included;
  
  	if (data->tls_out == NULL)
  		return -1;
  	len = wpabuf_len(data->tls_out) - data->tls_out_pos;
  	wpa_printf(MSG_DEBUG, "SSL: %lu bytes left to be sent out (of total "
  		   "%lu bytes)",
  		   (unsigned long) len,
  		   (unsigned long) wpabuf_len(data->tls_out));
  
  	/*
  	 * Limit outgoing message to the configured maximum size. Fragment
  	 * message if needed.
  	 */
  	if (len > data->tls_out_limit) {
  		more_fragments = 1;
  		len = data->tls_out_limit;
  		wpa_printf(MSG_DEBUG, "SSL: sending %lu bytes, more fragments "
  			   "will follow", (unsigned long) len);
  	} else
  		more_fragments = 0;
  
  	length_included = data->tls_out_pos == 0 &&
  		(wpabuf_len(data->tls_out) > data->tls_out_limit ||
  		 data->include_tls_length);
  	if (!length_included &&
  	    eap_type == EAP_TYPE_PEAP && peap_version == 0 &&
  	    !tls_connection_established(data->eap->ssl_ctx, data->conn)) {
  		/*
  		 * Windows Server 2008 NPS really wants to have the TLS Message
  		 * length included in phase 0 even for unfragmented frames or
  		 * it will get very confused with Compound MAC calculation and
  		 * Outer TLVs.
  		 */
  		length_included = 1;
  	}
  
  	*out_data = eap_tls_msg_alloc(eap_type, 1 + length_included * 4 + len,
  				      EAP_CODE_RESPONSE, id);
  	if (*out_data == NULL)
  		return -1;
  
  	flags = wpabuf_put(*out_data, 1);
  	*flags = peap_version;
  	if (more_fragments)
  		*flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS;
  	if (length_included) {
  		*flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED;
  		wpabuf_put_be32(*out_data, wpabuf_len(data->tls_out));
  	}
  
  	wpabuf_put_data(*out_data,
  			wpabuf_head_u8(data->tls_out) + data->tls_out_pos,
  			len);
  	data->tls_out_pos += len;
  
  	if (!more_fragments)
  		eap_peer_tls_reset_output(data);
  
  	return ret;
  }
  
  
  /**
   * eap_peer_tls_process_helper - Process TLS handshake message
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
   * @peap_version: Version number for EAP-PEAP/TTLS
   * @id: EAP identifier for the response
   * @in_data: Message received from the server
   * @out_data: Buffer for returning a pointer to the response message
   * Returns: 0 on success, 1 if more input data is needed, 2 if application data
   * is available, or -1 on failure
   *
   * This function can be used to process TLS handshake messages. It reassembles
   * the received fragments and uses a TLS library to process the messages. The
   * response data from the TLS library is fragmented to suitable output messages
   * that the caller can send out.
   *
   * out_data is used to return the response message if the return value of this
   * function is 0, 2, or -1. In case of failure, the message is likely a TLS
   * alarm message. The caller is responsible for freeing the allocated buffer if
   * *out_data is not %NULL.
   *
   * This function is called for each received TLS message during the TLS
   * handshake after eap_peer_tls_process_init() call and possible processing of
   * TLS Flags field. Once the handshake has been completed, i.e., when
   * tls_connection_established() returns 1, EAP method specific decrypting of
   * the tunneled data is used.
   */
  int eap_peer_tls_process_helper(struct eap_sm *sm, struct eap_ssl_data *data,
  				enum eap_type eap_type, int peap_version,
  				u8 id, const struct wpabuf *in_data,
  				struct wpabuf **out_data)
  {
  	int ret = 0;
  
  	*out_data = NULL;
  
  	if (data->tls_out && wpabuf_len(data->tls_out) > 0 &&
  	    wpabuf_len(in_data) > 0) {
  		wpa_printf(MSG_DEBUG, "SSL: Received non-ACK when output "
  			   "fragments are waiting to be sent out");
  		return -1;
  	}
  
  	if (data->tls_out == NULL || wpabuf_len(data->tls_out) == 0) {
  		/*
  		 * No more data to send out - expect to receive more data from
  		 * the AS.
  		 */
  		int res = eap_tls_process_input(sm, data, in_data, out_data);
  		char buf[20];
  
  		if (res) {
  			/*
  			 * Input processing failed (res = -1) or more data is
  			 * needed (res = 1).
  			 */
  			return res;
  		}
  
  		/*
  		 * The incoming message has been reassembled and processed. The
  		 * response was allocated into data->tls_out buffer.
  		 */
  
  		if (tls_get_version(data->ssl_ctx, data->conn,
  				    buf, sizeof(buf)) == 0) {
  			wpa_printf(MSG_DEBUG, "SSL: Using TLS version %s", buf);
  			data->tls_v13 = os_strcmp(buf, "TLSv1.3") == 0;
  		}
  	}
  
  	if (data->tls_out == NULL) {
  		/*
  		 * No outgoing fragments remaining from the previous message
  		 * and no new message generated. This indicates an error in TLS
  		 * processing.
  		 */
  		eap_peer_tls_reset_output(data);
  		return -1;
  	}
  
  	if (tls_connection_get_failed(data->ssl_ctx, data->conn)) {
  		/* TLS processing has failed - return error */
  		wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to "
  			   "report error (len=%u)",
  			   (unsigned int) wpabuf_len(data->tls_out));
  		ret = -1;
  		/* TODO: clean pin if engine used? */
  		if (wpabuf_len(data->tls_out) == 0) {
  			wpabuf_free(data->tls_out);
  			data->tls_out = NULL;
  			return -1;
  		}
  	}
  
  	if (wpabuf_len(data->tls_out) == 0) {
  		/*
  		 * TLS negotiation should now be complete since all other cases
  		 * needing more data should have been caught above based on
  		 * the TLS Message Length field.
  		 */
  		wpa_printf(MSG_DEBUG, "SSL: No data to be sent out");
  		wpabuf_free(data->tls_out);
  		data->tls_out = NULL;
  		return 1;
  	}
  
  	/* Send the pending message (in fragments, if needed). */
  	return eap_tls_process_output(data, eap_type, peap_version, id, ret,
  				      out_data);
  }
  
  
  /**
   * eap_peer_tls_build_ack - Build a TLS ACK frame
   * @id: EAP identifier for the response
   * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
   * @peap_version: Version number for EAP-PEAP/TTLS
   * Returns: Pointer to the allocated ACK frame or %NULL on failure
   */
  struct wpabuf * eap_peer_tls_build_ack(u8 id, enum eap_type eap_type,
  				       int peap_version)
  {
  	struct wpabuf *resp;
  
  	resp = eap_tls_msg_alloc(eap_type, 1, EAP_CODE_RESPONSE, id);
  	if (resp == NULL)
  		return NULL;
  	wpa_printf(MSG_DEBUG, "SSL: Building ACK (type=%d id=%d ver=%d)",
  		   (int) eap_type, id, peap_version);
  	wpabuf_put_u8(resp, peap_version); /* Flags */
  	return resp;
  }
  
  
  /**
   * eap_peer_tls_reauth_init - Re-initialize shared TLS for session resumption
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * Returns: 0 on success, -1 on failure
   */
  int eap_peer_tls_reauth_init(struct eap_sm *sm, struct eap_ssl_data *data)
  {
  	eap_peer_tls_reset_input(data);
  	eap_peer_tls_reset_output(data);
  	return tls_connection_shutdown(data->ssl_ctx, data->conn);
  }
  
  
  /**
   * eap_peer_tls_status - Get TLS status
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @buf: Buffer for status information
   * @buflen: Maximum buffer length
   * @verbose: Whether to include verbose status information
   * Returns: Number of bytes written to buf.
   */
  int eap_peer_tls_status(struct eap_sm *sm, struct eap_ssl_data *data,
  			char *buf, size_t buflen, int verbose)
  {
  	char version[20], name[128];
  	int len = 0, ret;
  
  	if (tls_get_version(data->ssl_ctx, data->conn, version,
  			    sizeof(version)) < 0)
  		version[0] = '\0';
  	if (tls_get_cipher(data->ssl_ctx, data->conn, name, sizeof(name)) < 0)
  		name[0] = '\0';
  
  	ret = os_snprintf(buf + len, buflen - len,
  			  "eap_tls_version=%s\n"
  			  "EAP TLS cipher=%s\n"
  			  "tls_session_reused=%d\n",
  			  version, name,
  			  tls_connection_resumed(data->ssl_ctx, data->conn));
  	if (os_snprintf_error(buflen - len, ret))
  		return len;
  	len += ret;
  
  	return len;
  }
  
  
  /**
   * eap_peer_tls_process_init - Initial validation/processing of EAP requests
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
   * @ret: Return values from EAP request validation and processing
   * @reqData: EAP request to be processed (eapReqData)
   * @len: Buffer for returning length of the remaining payload
   * @flags: Buffer for returning TLS flags
   * Returns: Pointer to payload after TLS flags and length or %NULL on failure
   *
   * This function validates the EAP header and processes the optional TLS
   * Message Length field. If this is the first fragment of a TLS message, the
   * TLS reassembly code is initialized to receive the indicated number of bytes.
   *
   * EAP-TLS, EAP-PEAP, EAP-TTLS, and EAP-FAST methods are expected to use this
   * function as the first step in processing received messages. They will need
   * to process the flags (apart from Message Length Included) that are returned
   * through the flags pointer and the message payload that will be returned (and
   * the length is returned through the len pointer). Return values (ret) are set
   * for continuation of EAP method processing. The caller is responsible for
   * setting these to indicate completion (either success or failure) based on
   * the authentication result.
   */
  const u8 * eap_peer_tls_process_init(struct eap_sm *sm,
  				     struct eap_ssl_data *data,
  				     enum eap_type eap_type,
  				     struct eap_method_ret *ret,
  				     const struct wpabuf *reqData,
  				     size_t *len, u8 *flags)
  {
  	const u8 *pos;
  	size_t left;
  	unsigned int tls_msg_len;
  
  	if (tls_get_errors(data->ssl_ctx)) {
  		wpa_printf(MSG_INFO, "SSL: TLS errors detected");
  		ret->ignore = true;
  		return NULL;
  	}
  
  	if (eap_type == EAP_UNAUTH_TLS_TYPE)
  		pos = eap_hdr_validate(EAP_VENDOR_UNAUTH_TLS,
  				       EAP_VENDOR_TYPE_UNAUTH_TLS, reqData,
  				       &left);
  	else if (eap_type == EAP_WFA_UNAUTH_TLS_TYPE)
  		pos = eap_hdr_validate(EAP_VENDOR_WFA_NEW,
  				       EAP_VENDOR_WFA_UNAUTH_TLS, reqData,
  				       &left);
  	else
  		pos = eap_hdr_validate(EAP_VENDOR_IETF, eap_type, reqData,
  				       &left);
  	if (pos == NULL) {
  		ret->ignore = true;
  		return NULL;
  	}
  	if (left == 0) {
  		wpa_printf(MSG_DEBUG, "SSL: Invalid TLS message: no Flags "
  			   "octet included");
  		if (!sm->workaround) {
  			ret->ignore = true;
  			return NULL;
  		}
  
  		wpa_printf(MSG_DEBUG, "SSL: Workaround - assume no Flags "
  			   "indicates ACK frame");
  		*flags = 0;
  	} else {
  		*flags = *pos++;
  		left--;
  	}
  	wpa_printf(MSG_DEBUG, "SSL: Received packet(len=%lu) - "
  		   "Flags 0x%02x", (unsigned long) wpabuf_len(reqData),
  		   *flags);
  	if (*flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) {
  		if (left < 4) {
  			wpa_printf(MSG_INFO, "SSL: Short frame with TLS "
  				   "length");
  			ret->ignore = true;
  			return NULL;
  		}
  		tls_msg_len = WPA_GET_BE32(pos);
  		wpa_printf(MSG_DEBUG, "SSL: TLS Message Length: %d",
  			   tls_msg_len);
  		if (data->tls_in_left == 0) {
  			data->tls_in_total = tls_msg_len;
  			data->tls_in_left = tls_msg_len;
  			wpabuf_free(data->tls_in);
  			data->tls_in = NULL;
  		}
  		pos += 4;
  		left -= 4;
  
  		if (left > tls_msg_len) {
  			wpa_printf(MSG_INFO, "SSL: TLS Message Length (%d "
  				   "bytes) smaller than this fragment (%d "
  				   "bytes)", (int) tls_msg_len, (int) left);
  			ret->ignore = true;
  			return NULL;
  		}
  	}
  
  	ret->ignore = false;
  	ret->methodState = METHOD_MAY_CONT;
  	ret->decision = DECISION_FAIL;
  	ret->allowNotifications = true;
  
  	*len = left;
  	return pos;
  }
  
  
  /**
   * eap_peer_tls_reset_input - Reset input buffers
   * @data: Data for TLS processing
   *
   * This function frees any allocated memory for input buffers and resets input
   * state.
   */
  void eap_peer_tls_reset_input(struct eap_ssl_data *data)
  {
  	data->tls_in_left = data->tls_in_total = 0;
  	wpabuf_free(data->tls_in);
  	data->tls_in = NULL;
  }
  
  
  /**
   * eap_peer_tls_reset_output - Reset output buffers
   * @data: Data for TLS processing
   *
   * This function frees any allocated memory for output buffers and resets
   * output state.
   */
  void eap_peer_tls_reset_output(struct eap_ssl_data *data)
  {
  	data->tls_out_pos = 0;
  	wpabuf_free(data->tls_out);
  	data->tls_out = NULL;
  }
  
  
  /**
   * eap_peer_tls_decrypt - Decrypt received phase 2 TLS message
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @in_data: Message received from the server
   * @in_decrypted: Buffer for returning a pointer to the decrypted message
   * Returns: 0 on success, 1 if more input data is needed, or -1 on failure
   */
  int eap_peer_tls_decrypt(struct eap_sm *sm, struct eap_ssl_data *data,
  			 const struct wpabuf *in_data,
  			 struct wpabuf **in_decrypted)
  {
  	const struct wpabuf *msg;
  	int need_more_input;
  
  	msg = eap_peer_tls_data_reassemble(data, in_data, &need_more_input);
  	if (msg == NULL)
  		return need_more_input ? 1 : -1;
  
  	*in_decrypted = tls_connection_decrypt(data->ssl_ctx, data->conn, msg);
  	eap_peer_tls_reset_input(data);
  	if (*in_decrypted == NULL) {
  		wpa_printf(MSG_INFO, "SSL: Failed to decrypt Phase 2 data");
  		return -1;
  	}
  	return 0;
  }
  
  
  /**
   * eap_peer_tls_encrypt - Encrypt phase 2 TLS message
   * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
   * @data: Data for TLS processing
   * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
   * @peap_version: Version number for EAP-PEAP/TTLS
   * @id: EAP identifier for the response
   * @in_data: Plaintext phase 2 data to encrypt or %NULL to continue fragments
   * @out_data: Buffer for returning a pointer to the encrypted response message
   * Returns: 0 on success, -1 on failure
   */
  int eap_peer_tls_encrypt(struct eap_sm *sm, struct eap_ssl_data *data,
  			 enum eap_type eap_type, int peap_version, u8 id,
  			 const struct wpabuf *in_data,
  			 struct wpabuf **out_data)
  {
  	if (in_data) {
  		eap_peer_tls_reset_output(data);
  		data->tls_out = tls_connection_encrypt(data->ssl_ctx,
  						       data->conn, in_data);
  		if (data->tls_out == NULL) {
  			wpa_printf(MSG_INFO, "SSL: Failed to encrypt Phase 2 "
  				   "data (in_len=%lu)",
  				   (unsigned long) wpabuf_len(in_data));
  			eap_peer_tls_reset_output(data);
  			return -1;
  		}
  	}
  
  	return eap_tls_process_output(data, eap_type, peap_version, id, 0,
  				      out_data);
  }
  
  
  /**
   * eap_peer_select_phase2_methods - Select phase 2 EAP method
   * @config: Pointer to the network configuration
   * @prefix: 'phase2' configuration prefix, e.g., "auth="
   * @types: Buffer for returning allocated list of allowed EAP methods
   * @num_types: Buffer for returning number of allocated EAP methods
   * Returns: 0 on success, -1 on failure
   *
   * This function is used to parse EAP method list and select allowed methods
   * for Phase2 authentication.
   */
  int eap_peer_select_phase2_methods(struct eap_peer_config *config,
  				   const char *prefix,
  				   struct eap_method_type **types,
  				   size_t *num_types, int use_machine_cred)
  {
  	char *start, *pos, *buf;
  	struct eap_method_type *methods = NULL, *_methods;
  	u32 method;
  	size_t num_methods = 0, prefix_len;
  	const char *phase2;
  
  	if (!config)
  		goto get_defaults;
  	phase2 = use_machine_cred ? config->machine_phase2 : config->phase2;
  	if (!phase2)
  		goto get_defaults;
  
  	start = buf = os_strdup(phase2);
  	if (buf == NULL)
  		return -1;
  
  	prefix_len = os_strlen(prefix);
  
  	while (start && *start != '\0') {
  		int vendor;
  		pos = os_strstr(start, prefix);
  		if (pos == NULL)
  			break;
  		if (start != pos && *(pos - 1) != ' ') {
  			start = pos + prefix_len;
  			continue;
  		}
  
  		start = pos + prefix_len;
  		pos = os_strchr(start, ' ');
  		if (pos)
  			*pos++ = '\0';
  		method = eap_get_phase2_type(start, &vendor);
  		if (vendor == EAP_VENDOR_IETF && method == EAP_TYPE_NONE) {
  			wpa_printf(MSG_ERROR, "TLS: Unsupported Phase2 EAP "
  				   "method '%s'", start);
  			os_free(methods);
  			os_free(buf);
  			return -1;
  		} else {
  			num_methods++;
  			_methods = os_realloc_array(methods, num_methods,
  						    sizeof(*methods));
  			if (_methods == NULL) {
  				os_free(methods);
  				os_free(buf);
  				return -1;
  			}
  			methods = _methods;
  			methods[num_methods - 1].vendor = vendor;
  			methods[num_methods - 1].method = method;
  		}
  
  		start = pos;
  	}
  
  	os_free(buf);
  
  get_defaults:
  	if (methods == NULL)
  		methods = eap_get_phase2_types(config, &num_methods);
  
  	if (methods == NULL) {
  		wpa_printf(MSG_ERROR, "TLS: No Phase2 EAP methods available");
  		return -1;
  	}
  	wpa_hexdump(MSG_DEBUG, "TLS: Phase2 EAP types",
  		    (u8 *) methods,
  		    num_methods * sizeof(struct eap_method_type));
  
  	*types = methods;
  	*num_types = num_methods;
  
  	return 0;
  }
  
  
  /**
   * eap_peer_tls_phase2_nak - Generate EAP-Nak for Phase 2
   * @types: Buffer for returning allocated list of allowed EAP methods
   * @num_types: Buffer for returning number of allocated EAP methods
   * @hdr: EAP-Request header (and the following EAP type octet)
   * @resp: Buffer for returning the EAP-Nak message
   * Returns: 0 on success, -1 on failure
   */
  int eap_peer_tls_phase2_nak(struct eap_method_type *types, size_t num_types,
  			    struct eap_hdr *hdr, struct wpabuf **resp)
  {
  	u8 *pos = (u8 *) (hdr + 1);
  	(void)pos;
  	size_t i;
  
  	/* TODO: add support for expanded Nak */
  	wpa_printf(MSG_DEBUG, "TLS: Phase 2 Request: Nak type=%d", *pos);
  	wpa_hexdump(MSG_DEBUG, "TLS: Allowed Phase2 EAP types",
  		    (u8 *) types, num_types * sizeof(struct eap_method_type));
  	*resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_NAK, num_types,
  			      EAP_CODE_RESPONSE, hdr->identifier);
  	if (*resp == NULL)
  		return -1;
  
  	for (i = 0; i < num_types; i++) {
  		if (types[i].vendor == EAP_VENDOR_IETF &&
  		    types[i].method < 256)
  			wpabuf_put_u8(*resp, types[i].method);
  	}
  
  	eap_update_len(*resp);
  
  	return 0;
  }
  