static upper size limit for PA-TNC messages

27 files changed, 245 insertions, 62 deletions

diff --git a/src/libimcv/ietf/ietf_attr_pa_tnc_error.c b/src/libimcv/ietf/ietf_attr_pa_tnc_error.c
index 6daee1a77..479c47c30 100644
--- a/src/libimcv/ietf/ietf_attr_pa_tnc_error.c
+++ b/src/libimcv/ietf/ietf_attr_pa_tnc_error.c
@@ -192,6 +192,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PA_ERROR_HEADER_SIZE + PA_ERROR_MSG_INFO_SIZE);
 	writer->write_uint8 (writer, PA_ERROR_RESERVED);
 	writer->write_uint24(writer, this->error_vendor_id);
diff --git a/src/libimcv/ietf/ietf_attr_port_filter.c b/src/libimcv/ietf/ietf_attr_port_filter.c
index b53019657..ebf498cc0 100644
--- a/src/libimcv/ietf/ietf_attr_port_filter.c
+++ b/src/libimcv/ietf/ietf_attr_port_filter.c
@@ -125,6 +125,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	enumerator_t *enumerator;
 	port_entry_t *entry;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(this->ports->get_count(this->ports) *
 							   PORT_FILTER_ENTRY_SIZE);
 
diff --git a/src/libimcv/ietf/ietf_attr_product_info.c b/src/libimcv/ietf/ietf_attr_product_info.c
index 548793547..703a8ab6d 100644
--- a/src/libimcv/ietf/ietf_attr_product_info.c
+++ b/src/libimcv/ietf/ietf_attr_product_info.c
@@ -122,6 +122,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	bio_writer_t *writer;
 	chunk_t product_name;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	product_name = chunk_create(this->product_name, strlen(this->product_name));
 
 	writer = bio_writer_create(PRODUCT_INFO_MIN_SIZE);
diff --git a/src/libimcv/imc/imc_agent.c b/src/libimcv/imc/imc_agent.c
index fcf8dac78..844cae810 100644
--- a/src/libimcv/imc/imc_agent.c
+++ b/src/libimcv/imc/imc_agent.c
@@ -48,6 +48,11 @@ struct private_imc_agent_t {
 	TNC_MessageSubtype subtype;
 
 	/**
+	 * Maximum PA-TNC Message size
+	 */
+	size_t max_msg_len;
+
+	/**
 	 * ID of IMC as assigned by TNCC
 	 */
 	TNC_IMCID id;
@@ -461,6 +466,7 @@ METHOD(imc_agent_t, send_message, TNC_Result,
 	pa_tnc_attr_t *attr;
 	pa_tnc_msg_t *pa_tnc_msg;
 	chunk_t msg;
+	enumerator_t *enumerator;
 
 	state = find_connection(this, connection_id);
 	if (!state)
@@ -470,36 +476,52 @@ METHOD(imc_agent_t, send_message, TNC_Result,
 		return TNC_RESULT_FATAL;
 	}
 
-	pa_tnc_msg = pa_tnc_msg_create();
-
-	while (attr_list->remove_first(attr_list, (void**)&attr) == SUCCESS)
+	while (attr_list->get_count(attr_list))
 	{
-		pa_tnc_msg->add_attribute(pa_tnc_msg, attr);
-	}
-	pa_tnc_msg->build(pa_tnc_msg);
-	msg = pa_tnc_msg->get_encoding(pa_tnc_msg);
+		pa_tnc_msg = pa_tnc_msg_create(this->max_msg_len);
 
-	if (state->has_long(state) && this->send_message_long)
-	{
-		if (!src_imc_id)
+		enumerator = attr_list->create_enumerator(attr_list);
+		while (enumerator->enumerate(enumerator, &attr))
 		{
-			src_imc_id = this->id;
+			if (!pa_tnc_msg->add_attribute(pa_tnc_msg, attr))
+			{
+				break;
+			}
+			attr_list->remove_at(attr_list, enumerator);
 		}
-		msg_flags = excl ? TNC_MESSAGE_FLAGS_EXCLUSIVE : 0;
+		enumerator->destroy(enumerator);
 
-		result = this->send_message_long(src_imc_id, connection_id, msg_flags,
-										 msg.ptr, msg.len, this->vendor_id,
-										 this->subtype, dst_imv_id);
-	}
-	else if (this->send_message)
-	{
-		type = (this->vendor_id << 8) | this->subtype;
+		/* build and send the PA-TNC message via the IF-IMC interface */
+		pa_tnc_msg->build(pa_tnc_msg);
+		msg = pa_tnc_msg->get_encoding(pa_tnc_msg);
 
-		result = this->send_message(this->id, connection_id, msg.ptr, msg.len,
-									type);
-	}
-	pa_tnc_msg->destroy(pa_tnc_msg);
+		if (state->has_long(state) && this->send_message_long)
+		{
+			if (!src_imc_id)
+			{
+				src_imc_id = this->id;
+			}
+			msg_flags = excl ? TNC_MESSAGE_FLAGS_EXCLUSIVE : 0;
+
+			result = this->send_message_long(src_imc_id, connection_id,
+								msg_flags, msg.ptr, msg.len, this->vendor_id,
+								this->subtype, dst_imv_id);
+		}
+		else if (this->send_message)
+		{
+			type = (this->vendor_id << 8) | this->subtype;
+
+			result = this->send_message(this->id, connection_id, msg.ptr,
+								msg.len, type);
+		}
 
+		pa_tnc_msg->destroy(pa_tnc_msg);
+
+		if (result != TNC_RESULT_SUCCESS)
+		{
+			break;
+		}
+	}
 	return result;
 }
 
@@ -549,7 +571,7 @@ METHOD(imc_agent_t, receive_message, TNC_Result,
 			break;
 		case VERIFY_ERROR:
 			/* build error message */
-			error_msg = pa_tnc_msg_create();
+			error_msg = pa_tnc_msg_create(this->max_msg_len);
 			enumerator = pa_msg->create_error_enumerator(pa_msg);
 			while (enumerator->enumerate(enumerator, &error_attr))
 			{
@@ -693,6 +715,7 @@ imc_agent_t *imc_agent_create(const char *name,
 		.name = name,
 		.vendor_id = vendor_id,
 		.subtype = subtype,
+		.max_msg_len = 65490,
 		.id = id,
 		.additional_ids = linked_list_create(),
 		.connections = linked_list_create(),
diff --git a/src/libimcv/imv/imv_agent.c b/src/libimcv/imv/imv_agent.c
index b67dcadd5..9f0442180 100644
--- a/src/libimcv/imv/imv_agent.c
+++ b/src/libimcv/imv/imv_agent.c
@@ -48,6 +48,11 @@ struct private_imv_agent_t {
 	TNC_MessageSubtype subtype;
 
 	/**
+	 * Maximum PA-TNC Message size
+	 */
+	size_t max_msg_len;
+
+	/**
 	 * ID of IMV as assigned by TNCS
 	 */
 	TNC_IMVID id;
@@ -471,13 +476,14 @@ METHOD(imv_agent_t, send_message, TNC_Result,
 	private_imv_agent_t *this, TNC_ConnectionID connection_id, bool excl,
 	TNC_UInt32 src_imv_id, TNC_UInt32 dst_imc_id, linked_list_t *attr_list)
 {
-	TNC_Result result = TNC_RESULT_FATAL;
 	TNC_MessageType type;
 	TNC_UInt32 msg_flags;
+	TNC_Result result = TNC_RESULT_FATAL;
 	imv_state_t *state;
 	pa_tnc_attr_t *attr;
 	pa_tnc_msg_t *pa_tnc_msg;
 	chunk_t msg;
+	enumerator_t *enumerator;
 
 	state = find_connection(this, connection_id);
 	if (!state)
@@ -487,36 +493,53 @@ METHOD(imv_agent_t, send_message, TNC_Result,
 		return TNC_RESULT_FATAL;
 	}
 
-	pa_tnc_msg = pa_tnc_msg_create();
-
-	while (attr_list->remove_first(attr_list, (void**)&attr) == SUCCESS)
+	pa_tnc_msg = pa_tnc_msg_create(this->max_msg_len);
+	while (attr_list->get_count(attr_list))
 	{
-		pa_tnc_msg->add_attribute(pa_tnc_msg, attr);
-	}
-	pa_tnc_msg->build(pa_tnc_msg);
-	msg = pa_tnc_msg->get_encoding(pa_tnc_msg);
+		pa_tnc_msg = pa_tnc_msg_create(this->max_msg_len);
 
-	if (state->has_long(state) && this->send_message_long)
-	{
-		if (!src_imv_id)
+		enumerator = attr_list->create_enumerator(attr_list);
+		while (enumerator->enumerate(enumerator, &attr))
 		{
-			src_imv_id = this->id;
+			if (!pa_tnc_msg->add_attribute(pa_tnc_msg, attr))
+			{
+				break;
+			}
+			attr_list->remove_at(attr_list, enumerator);
 		}
-		msg_flags = excl ? TNC_MESSAGE_FLAGS_EXCLUSIVE : 0;
+		enumerator->destroy(enumerator);
 
-		result = this->send_message_long(src_imv_id, connection_id, msg_flags,
-										 msg.ptr, msg.len, this->vendor_id,
-										 this->subtype, dst_imc_id);
-	}
-	else if (this->send_message)
-	{
-		type = (this->vendor_id << 8) | this->subtype;
+		/* build and send the PA-TNC message via the IF-IMV interface */
+		pa_tnc_msg->build(pa_tnc_msg);
+		msg = pa_tnc_msg->get_encoding(pa_tnc_msg);
 
-		result = this->send_message(this->id, connection_id, msg.ptr, msg.len,
-									type);
-	}
-	pa_tnc_msg->destroy(pa_tnc_msg);
+		if (state->has_long(state) && this->send_message_long)
+		{
+			if (!src_imv_id)
+			{
+				src_imv_id = this->id;
+			}
+			msg_flags = excl ? TNC_MESSAGE_FLAGS_EXCLUSIVE : 0;
+
+			result = this->send_message_long(src_imv_id, connection_id,
+								msg_flags, msg.ptr, msg.len, this->vendor_id,
+								this->subtype, dst_imc_id);
+		}
+		else if (this->send_message)
+		{
+			type = (this->vendor_id << 8) | this->subtype;
+
+			result = this->send_message(this->id, connection_id, msg.ptr,
+								msg.len, type);
+		}
+
+		pa_tnc_msg->destroy(pa_tnc_msg);
 
+		if (result != TNC_RESULT_SUCCESS)
+		{
+			break;
+		}
+	}
 	return result;
 }
 
@@ -585,7 +608,7 @@ METHOD(imv_agent_t, receive_message, TNC_Result,
 			break;
 		case VERIFY_ERROR:
 			/* build error message */
-			error_msg = pa_tnc_msg_create();
+			error_msg = pa_tnc_msg_create(this->max_msg_len);
 			enumerator = pa_msg->create_error_enumerator(pa_msg);
 			while (enumerator->enumerate(enumerator, &error_attr))
 			{
@@ -791,6 +814,7 @@ imv_agent_t *imv_agent_create(const char *name,
 		.name = name,
 		.vendor_id = vendor_id,
 		.subtype = subtype,
+		.max_msg_len = 65490,
 		.id = id,
 		.additional_ids = linked_list_create(),
 		.connections = linked_list_create(),
diff --git a/src/libimcv/ita/ita_attr_command.c b/src/libimcv/ita/ita_attr_command.c
index 5c1577a7c..051825172 100644
--- a/src/libimcv/ita/ita_attr_command.c
+++ b/src/libimcv/ita/ita_attr_command.c
@@ -95,6 +95,10 @@ METHOD(pa_tnc_attr_t, set_noskip_flag,void,
 METHOD(pa_tnc_attr_t, build, void,
 	private_ita_attr_command_t *this)
 {
+	if (this->value.ptr)
+	{
+		return;
+	}
 	this->value = chunk_create(this->command, strlen(this->command));
 	this->value = chunk_clone(this->value);
 }
diff --git a/src/libimcv/ita/ita_attr_dummy.c b/src/libimcv/ita/ita_attr_dummy.c
index da9d235ef..16ffe65fd 100644
--- a/src/libimcv/ita/ita_attr_dummy.c
+++ b/src/libimcv/ita/ita_attr_dummy.c
@@ -95,6 +95,10 @@ METHOD(pa_tnc_attr_t, set_noskip_flag,void,
 METHOD(pa_tnc_attr_t, build, void,
 	private_ita_attr_dummy_t *this)
 {
+	if (this->value.ptr)
+	{
+		return;
+	}
 	this->value = chunk_alloc(this->size);
 	memset(this->value.ptr, 0xdd, this->value.len);
 }
diff --git a/src/libimcv/pa_tnc/pa_tnc_msg.c b/src/libimcv/pa_tnc/pa_tnc_msg.c
index b5df0a5b5..4c44693db 100644
--- a/src/libimcv/pa_tnc/pa_tnc_msg.c
+++ b/src/libimcv/pa_tnc/pa_tnc_msg.c
@@ -90,6 +90,16 @@ struct private_pa_tnc_msg_t {
 	u_int32_t identifier;
 
 	/**
+	 * Current PA-TNC Message size
+	 */
+	size_t msg_len;
+
+	/**
+	 * Maximum PA-TNC Message size
+	 */
+	size_t max_msg_len;
+
+	/**
 	 * Encoded message
 	 */
 	chunk_t encoding;
@@ -101,10 +111,25 @@ METHOD(pa_tnc_msg_t, get_encoding, chunk_t,
 	return this->encoding;
 }
 
-METHOD(pa_tnc_msg_t, add_attribute, void,
+METHOD(pa_tnc_msg_t, add_attribute, bool,
 	private_pa_tnc_msg_t *this, pa_tnc_attr_t *attr)
 {
+	chunk_t attr_value;
+	size_t attr_len;
+
+	attr->build(attr);
+	attr_value = attr->get_value(attr);
+	attr_len = PA_TNC_ATTR_HEADER_SIZE + attr_value.len;
+
+	if (this->msg_len + attr_len > this->max_msg_len)
+	{
+		/* attribute just does not fit into this message */
+		return FALSE;
+	}
+	this->msg_len += attr_len;
+
 	this->attributes->insert_last(this->attributes, attr);
+	return TRUE;
 }
 
 METHOD(pa_tnc_msg_t, build, void,
@@ -127,16 +152,15 @@ METHOD(pa_tnc_msg_t, build, void,
 	DBG2(DBG_TNC, "creating PA-TNC message with ID 0x%08x", this->identifier);
 
 	/* build message header */
-	writer = bio_writer_create(PA_TNC_HEADER_SIZE);
+	writer = bio_writer_create(this->msg_len);
 	writer->write_uint8 (writer, PA_TNC_VERSION);
 	writer->write_uint24(writer, PA_TNC_RESERVED);
 	writer->write_uint32(writer, this->identifier);
 
-	/* build and append encoding of PA-TNC attributes */
+	/* append encoded value of PA-TNC attributes */
 	enumerator = this->attributes->create_enumerator(this->attributes);
 	while (enumerator->enumerate(enumerator, &attr))
 	{
-		attr->build(attr);
 		vendor_id = attr->get_vendor_id(attr);
 		type = attr->get_type(attr);
 		value = attr->get_value(attr);
@@ -292,7 +316,7 @@ METHOD(pa_tnc_msg_t, process, status_t,
 						offset + PA_TNC_ATTR_HEADER_SIZE + attr_offset);
 			goto err;
 		}
-		add_attribute(this, attr);
+		this->attributes->insert_last(this->attributes, attr);
 		offset += length;
 	}
 
@@ -394,7 +418,7 @@ METHOD(pa_tnc_msg_t, destroy, void,
 /**
  * See header
  */
-pa_tnc_msg_t *pa_tnc_msg_create_from_data(chunk_t data)
+pa_tnc_msg_t *pa_tnc_msg_create(size_t max_msg_len)
 {
 	private_pa_tnc_msg_t *this;
 
@@ -409,9 +433,10 @@ pa_tnc_msg_t *pa_tnc_msg_create_from_data(chunk_t data)
 			.create_error_enumerator = _create_error_enumerator,
 			.destroy = _destroy,
 		},
-		.encoding = chunk_clone(data),
 		.attributes = linked_list_create(),
 		.errors = linked_list_create(),
+		.msg_len = PA_TNC_HEADER_SIZE,
+		.max_msg_len = max_msg_len,
 	);
 
 	return &this->public;
@@ -420,8 +445,26 @@ pa_tnc_msg_t *pa_tnc_msg_create_from_data(chunk_t data)
 /**
  * See header
  */
-pa_tnc_msg_t *pa_tnc_msg_create(void)
+pa_tnc_msg_t *pa_tnc_msg_create_from_data(chunk_t data)
 {
-	return pa_tnc_msg_create_from_data(chunk_empty);
+	private_pa_tnc_msg_t *this;
+
+	INIT(this,
+		.public = {
+			.get_encoding = _get_encoding,
+			.add_attribute = _add_attribute,
+			.build = _build,
+			.process = _process,
+			.process_ietf_std_errors = _process_ietf_std_errors,
+			.create_attribute_enumerator = _create_attribute_enumerator,
+			.create_error_enumerator = _create_error_enumerator,
+			.destroy = _destroy,
+		},
+		.encoding = chunk_clone(data),
+		.attributes = linked_list_create(),
+		.errors = linked_list_create(),
+	);
+
+	return &this->public;
 }
 
diff --git a/src/libimcv/pa_tnc/pa_tnc_msg.h b/src/libimcv/pa_tnc/pa_tnc_msg.h
index c3ce829d5..48579479c 100644
--- a/src/libimcv/pa_tnc/pa_tnc_msg.h
+++ b/src/libimcv/pa_tnc/pa_tnc_msg.h
@@ -46,8 +46,9 @@ struct pa_tnc_msg_t {
 	 * Add a PA-TNC attribute
 	 *
 	 * @param attr				PA-TNC attribute to be addedd
+	 * @return					TRUE if attribute fit into message and was added
 	 */
-	void (*add_attribute)(pa_tnc_msg_t *this, pa_tnc_attr_t* attr);
+	bool (*add_attribute)(pa_tnc_msg_t *this, pa_tnc_attr_t* attr);
 
 	/**
 	 * Build the PA-TNC message
@@ -91,7 +92,7 @@ struct pa_tnc_msg_t {
 /**
  * Create an empty PA-TNC message
  */
-pa_tnc_msg_t* pa_tnc_msg_create(void);
+pa_tnc_msg_t* pa_tnc_msg_create(size_t max_msg_len);
 
 /**
  * Create an unprocessed PA-TNC message from received data
diff --git a/src/libimcv/plugins/imv_test/imv_test.c b/src/libimcv/plugins/imv_test/imv_test.c
index c2295e155..b26a92654 100644
--- a/src/libimcv/plugins/imv_test/imv_test.c
+++ b/src/libimcv/plugins/imv_test/imv_test.c
@@ -108,7 +108,7 @@ static TNC_Result receive_message(TNC_IMVID imv_id,
 	enumerator_t *enumerator;
 	TNC_Result result;
 	int rounds;
-	bool fatal_error, retry = FALSE;
+	bool fatal_error, received_command = FALSE, retry = FALSE;
 
 	if (!imv_test)
 	{
@@ -154,6 +154,7 @@ static TNC_Result receive_message(TNC_IMVID imv_id,
 			ita_attr_command_t *ita_attr;
 			char *command;
 	
+			received_command = TRUE;
 			ita_attr = (ita_attr_command_t*)attr;
 			command = ita_attr->get_command(ita_attr);
 
@@ -228,7 +229,9 @@ static TNC_Result receive_message(TNC_IMVID imv_id,
 		return result;
 	}
 
-	return imv_test->provide_recommendation(imv_test, connection_id);
+	return received_command ?
+				imv_test->provide_recommendation(imv_test, connection_id) :
+				TNC_RESULT_SUCCESS;
 }
 
 /**
diff --git a/src/libpts/tcg/tcg_pts_attr_aik.c b/src/libpts/tcg/tcg_pts_attr_aik.c
index 9be3794b6..e8f60ca25 100644
--- a/src/libpts/tcg/tcg_pts_attr_aik.c
+++ b/src/libpts/tcg/tcg_pts_attr_aik.c
@@ -117,6 +117,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	cred_encoding_type_t encoding_type = CERT_ASN1_DER;
 	chunk_t aik_blob;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	if (this->aik->get_type(this->aik) == CERT_TRUSTED_PUBKEY)
 	{
 		flags |= PTS_AIK_FLAGS_NAKED_KEY;
diff --git a/src/libpts/tcg/tcg_pts_attr_dh_nonce_finish.c b/src/libpts/tcg/tcg_pts_attr_dh_nonce_finish.c
index dce98e87d..0494f5868 100644
--- a/src/libpts/tcg/tcg_pts_attr_dh_nonce_finish.c
+++ b/src/libpts/tcg/tcg_pts_attr_dh_nonce_finish.c
@@ -128,6 +128,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_DH_NONCE_FINISH_SIZE);
 	writer->write_uint8 (writer, PTS_DH_NONCE_FINISH_RESERVED);
 	writer->write_uint8 (writer, this->initiator_nonce.len);
diff --git a/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_req.c b/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_req.c
index 36266fe12..9fb1c3d24 100644
--- a/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_req.c
+++ b/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_req.c
@@ -119,6 +119,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_DH_NONCE_PARAMS_REQ_SIZE);
 	writer->write_uint8 (writer, PTS_DH_NONCE_PARAMS_REQ_RESERVED);
 	writer->write_uint8 (writer, this->min_nonce_len);
diff --git a/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_resp.c b/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_resp.c
index 09bfa3aac..8df7f7a34 100644
--- a/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_resp.c
+++ b/src/libpts/tcg/tcg_pts_attr_dh_nonce_params_resp.c
@@ -135,6 +135,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_DH_NONCE_PARAMS_RESP_SIZE);
 	writer->write_uint24(writer, PTS_DH_NONCE_PARAMS_RESP_RESERVED);
 	writer->write_uint8 (writer, this->responder_nonce.len);
diff --git a/src/libpts/tcg/tcg_pts_attr_file_meas.c b/src/libpts/tcg/tcg_pts_attr_file_meas.c
index 737da65c1..eba3607f6 100644
--- a/src/libpts/tcg/tcg_pts_attr_file_meas.c
+++ b/src/libpts/tcg/tcg_pts_attr_file_meas.c
@@ -135,6 +135,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	chunk_t measurement;
 	bool first = TRUE;
 	
+	if (this->value.ptr)
+	{
+		return;
+	}
 	number_of_files = this->measurements->get_file_count(this->measurements);
 	request_id = this->measurements->get_request_id(this->measurements);
 
diff --git a/src/libpts/tcg/tcg_pts_attr_gen_attest_evid.c b/src/libpts/tcg/tcg_pts_attr_gen_attest_evid.c
index 054285c4e..303ae59db 100644
--- a/src/libpts/tcg/tcg_pts_attr_gen_attest_evid.c
+++ b/src/libpts/tcg/tcg_pts_attr_gen_attest_evid.c
@@ -110,6 +110,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_GEN_ATTEST_EVID_SIZE);
 	writer->write_uint32 (writer, PTS_GEN_ATTEST_EVID_RESERVED);
 
diff --git a/src/libpts/tcg/tcg_pts_attr_get_aik.c b/src/libpts/tcg/tcg_pts_attr_get_aik.c
index 1875375a4..c279fa5cd 100644
--- a/src/libpts/tcg/tcg_pts_attr_get_aik.c
+++ b/src/libpts/tcg/tcg_pts_attr_get_aik.c
@@ -107,6 +107,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_GET_AIK_SIZE);
 	writer->write_uint32 (writer, PTS_GET_AIK_RESERVED);
 
diff --git a/src/libpts/tcg/tcg_pts_attr_get_tpm_version_info.c b/src/libpts/tcg/tcg_pts_attr_get_tpm_version_info.c
index cb6834ca5..8f2fb42d4 100644
--- a/src/libpts/tcg/tcg_pts_attr_get_tpm_version_info.c
+++ b/src/libpts/tcg/tcg_pts_attr_get_tpm_version_info.c
@@ -110,6 +110,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_GET_TPM_VER_INFO_SIZE);
 	writer->write_uint32 (writer, PTS_GET_TPM_VER_INFO_RESERVED);
 
diff --git a/src/libpts/tcg/tcg_pts_attr_meas_algo.c b/src/libpts/tcg/tcg_pts_attr_meas_algo.c
index ed520e3cd..16982dedb 100644
--- a/src/libpts/tcg/tcg_pts_attr_meas_algo.c
+++ b/src/libpts/tcg/tcg_pts_attr_meas_algo.c
@@ -113,6 +113,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_MEAS_ALGO_SIZE);
 	writer->write_uint16(writer, PTS_MEAS_ALGO_RESERVED);
 	writer->write_uint16(writer, this->algorithms);
diff --git a/src/libpts/tcg/tcg_pts_attr_proto_caps.c b/src/libpts/tcg/tcg_pts_attr_proto_caps.c
index 055c750ff..8d75a7cd5 100644
--- a/src/libpts/tcg/tcg_pts_attr_proto_caps.c
+++ b/src/libpts/tcg/tcg_pts_attr_proto_caps.c
@@ -113,6 +113,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_PROTO_CAPS_SIZE);
 	writer->write_uint16(writer, PTS_PROTO_CAPS_RESERVED);
 	writer->write_uint16(writer, this->flags);
diff --git a/src/libpts/tcg/tcg_pts_attr_req_file_meas.c b/src/libpts/tcg/tcg_pts_attr_req_file_meas.c
index 17781f745..823a61a2e 100644
--- a/src/libpts/tcg/tcg_pts_attr_req_file_meas.c
+++ b/src/libpts/tcg/tcg_pts_attr_req_file_meas.c
@@ -136,6 +136,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	chunk_t pathname;
 	bio_writer_t *writer;
 	
+	if (this->value.ptr)
+	{
+		return;
+	}
 	if (this->directory_flag)
 	{
 		flags |= DIRECTORY_CONTENTS_FLAG;
diff --git a/src/libpts/tcg/tcg_pts_attr_req_file_meta.c b/src/libpts/tcg/tcg_pts_attr_req_file_meta.c
index bef6b5db6..847e46824 100644
--- a/src/libpts/tcg/tcg_pts_attr_req_file_meta.c
+++ b/src/libpts/tcg/tcg_pts_attr_req_file_meta.c
@@ -129,6 +129,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	chunk_t pathname;
 	bio_writer_t *writer;
 	
+	if (this->value.ptr)
+	{
+		return;
+	}
 	if (this->directory_flag)
 	{
 		flags |= DIRECTORY_CONTENTS_FLAG;
diff --git a/src/libpts/tcg/tcg_pts_attr_req_func_comp_evid.c b/src/libpts/tcg/tcg_pts_attr_req_func_comp_evid.c
index bfd108b9f..978bf10cb 100644
--- a/src/libpts/tcg/tcg_pts_attr_req_func_comp_evid.c
+++ b/src/libpts/tcg/tcg_pts_attr_req_func_comp_evid.c
@@ -177,6 +177,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	enumerator_t *enumerator;
 	entry_t *entry;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_REQ_FUNC_COMP_EVID_SIZE);
 
 	enumerator = this->list->create_enumerator(this->list);
diff --git a/src/libpts/tcg/tcg_pts_attr_simple_comp_evid.c b/src/libpts/tcg/tcg_pts_attr_simple_comp_evid.c
index d2c197ac4..1e1f0417a 100644
--- a/src/libpts/tcg/tcg_pts_attr_simple_comp_evid.c
+++ b/src/libpts/tcg/tcg_pts_attr_simple_comp_evid.c
@@ -195,6 +195,11 @@ METHOD(pa_tnc_attr_t, build, void,
 	time_t measurement_time;
 	chunk_t measurement, utc_time, pcr_before, pcr_after, policy_uri;
 	
+	if (this->value.ptr)
+	{
+		return;
+	}
+
 	/* Extract parameters from comp_evidence_t object */
 	name         = this->evidence->get_comp_func_name(this->evidence,
 							&depth);
diff --git a/src/libpts/tcg/tcg_pts_attr_simple_evid_final.c b/src/libpts/tcg/tcg_pts_attr_simple_evid_final.c
index 27720d509..f29dbf5c6 100644
--- a/src/libpts/tcg/tcg_pts_attr_simple_evid_final.c
+++ b/src/libpts/tcg/tcg_pts_attr_simple_evid_final.c
@@ -169,6 +169,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	bio_writer_t *writer;
 	u_int8_t flags;
 	
+	if (this->value.ptr)
+	{
+		return;
+	}
 	flags = this->flags & PTS_SIMPLE_EVID_FINAL_FLAG_MASK;
 
 	if (this->has_evid_sig)
diff --git a/src/libpts/tcg/tcg_pts_attr_tpm_version_info.c b/src/libpts/tcg/tcg_pts_attr_tpm_version_info.c
index 944a12cc9..ab08bc954 100644
--- a/src/libpts/tcg/tcg_pts_attr_tpm_version_info.c
+++ b/src/libpts/tcg/tcg_pts_attr_tpm_version_info.c
@@ -114,6 +114,10 @@ METHOD(pa_tnc_attr_t, build, void,
 {
 	bio_writer_t *writer;
 
+	if (this->value.ptr)
+	{
+		return;
+	}
 	writer = bio_writer_create(PTS_TPM_VER_INFO_SIZE);
 	writer->write_data(writer, this->tpm_version_info);
 
diff --git a/src/libpts/tcg/tcg_pts_attr_unix_file_meta.c b/src/libpts/tcg/tcg_pts_attr_unix_file_meta.c
index a9f4a115d..d1b1bcef7 100644
--- a/src/libpts/tcg/tcg_pts_attr_unix_file_meta.c
+++ b/src/libpts/tcg/tcg_pts_attr_unix_file_meta.c
@@ -148,6 +148,10 @@ METHOD(pa_tnc_attr_t, build, void,
 	pts_file_metadata_t *entry;
 	u_int64_t number_of_files;
 	
+	if (this->value.ptr)
+	{
+		return;
+	}
 	number_of_files = this->metadata->get_file_count(this->metadata);
 	writer = bio_writer_create(PTS_FILE_META_SIZE);