eap_tls_common.c

IEEE 802.11a/b/g 服务器端AP

		wpabuf_put_be32(*out_data, data->tls_out_len);
	}

	wpabuf_put_data(*out_data, &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
 * @in_len: Length of in_data
 * @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,
				EapType eap_type, int peap_version,
				u8 id, const u8 *in_data, size_t in_len,
				struct wpabuf **out_data)
{
	int ret = 0;

	*out_data = NULL;

	if (data->tls_out_len > 0 && in_len > 0) {
		wpa_printf(MSG_DEBUG, "SSL: Received non-ACK when output "
			   "fragments are waiting to be sent out");
		return -1;
	}

	if (data->tls_out_len == 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, in_len,
						out_data);
		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 (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(sm->ssl_ctx, data->conn)) {
		/* TLS processing has failed - return error */
		wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to "
			   "report error");
		ret = -1;
		/* TODO: clean pin if engine used? */
	}

	if (data->tls_out_len == 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");
		os_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, EapType eap_type,
				       int peap_version)
{
	struct wpabuf *resp;

	resp = eap_msg_alloc(EAP_VENDOR_IETF, 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(sm->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 name[128];
	int len = 0, ret;

	if (tls_get_cipher(sm->ssl_ctx, data->conn, name, sizeof(name)) == 0) {
		ret = os_snprintf(buf + len, buflen - len,
				  "EAP TLS cipher=%s\n", name);
		if (ret < 0 || (size_t) ret >= buflen - len)
			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,
				     EapType 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(sm->ssl_ctx)) {
		wpa_printf(MSG_INFO, "SSL: TLS errors detected");
		ret->ignore = TRUE;
		return NULL;
	}

	pos = eap_hdr_validate(EAP_VENDOR_IETF, eap_type, reqData, &left);
	if (pos == NULL) {
		ret->ignore = TRUE;
		return NULL;
	}
	*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;
			os_free(data->tls_in);
			data->tls_in = NULL;
			data->tls_in_len = 0;
		}
		pos += 4;
		left -= 4;
	}

	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 = data->tls_in_len = 0;
	os_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_len = 0;
	data->tls_out_pos = 0;
	os_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)
{
	int res;
	const u8 *msg;
	size_t msg_len, buf_len;
	int need_more_input;

	msg = eap_peer_tls_data_reassemble(data, wpabuf_head(in_data),
					   wpabuf_len(in_data), &msg_len,
					   &need_more_input);
	if (msg == NULL)
		return need_more_input ? 1 : -1;

	buf_len = wpabuf_len(in_data);
	if (data->tls_in_total > buf_len)
		buf_len = data->tls_in_total;
	/*
	 * Even though we try to disable TLS compression, it is possible that
	 * this cannot be done with all TLS libraries. Add extra buffer space
	 * to handle the possibility of the decrypted data being longer than
	 * input data.
	 */
	buf_len += 500;
	buf_len *= 3;
	*in_decrypted = wpabuf_alloc(buf_len ? buf_len : 1);
	if (*in_decrypted == NULL) {
		eap_peer_tls_reset_input(data);
		wpa_printf(MSG_WARNING, "SSL: Failed to allocate memory for "
			   "decryption");
		return -1;
	}

	res = tls_connection_decrypt(sm->ssl_ctx, data->conn, msg, msg_len,
				     wpabuf_mhead(*in_decrypted), buf_len);
	eap_peer_tls_reset_input(data);
	if (res < 0) {
		wpa_printf(MSG_INFO, "SSL: Failed to decrypt Phase 2 data");
		return -1;
	}
	wpabuf_put(*in_decrypted, res);
	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,
			 EapType eap_type, int peap_version, u8 id,
			 const struct wpabuf *in_data,
			 struct wpabuf **out_data)
{
	int res;
	size_t len;

	if (in_data) {
		eap_peer_tls_reset_output(data);
		len = wpabuf_len(in_data) + 100;
		data->tls_out = os_malloc(len);
		if (data->tls_out == NULL)
			return -1;

		res = tls_connection_encrypt(sm->ssl_ctx, data->conn,
					     wpabuf_head(in_data),
					     wpabuf_len(in_data),
					     data->tls_out, len);
		if (res < 0) {
			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;
		}

		data->tls_out_len = res;
	}

	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)
{
	char *start, *pos, *buf;
	struct eap_method_type *methods = NULL, *_methods;
	u8 method;
	size_t num_methods = 0, prefix_len;

	if (config == NULL || config->phase2 == NULL)
		goto get_defaults;

	start = buf = os_strdup(config->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);
		} else {
			num_methods++;
			_methods = os_realloc(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);
	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;
}