Implemented TLS Alert handling

15 files changed, 643 insertions, 80 deletions

diff --git a/src/libtls/Makefile.am b/src/libtls/Makefile.am
index 5e112f601..ff11ef41e 100644
--- a/src/libtls/Makefile.am
+++ b/src/libtls/Makefile.am
@@ -6,6 +6,7 @@ libtls_la_SOURCES = \
 	tls_protection.h tls_protection.c \
 	tls_compression.h tls_compression.c \
 	tls_fragmentation.h tls_fragmentation.c \
+	tls_alert.h tls_alert.c \
 	tls_crypto.h tls_crypto.c \
 	tls_prf.h tls_prf.c \
 	tls_reader.h tls_reader.c \
diff --git a/src/libtls/tls.c b/src/libtls/tls.c
index d46ce0084..42f71d753 100644
--- a/src/libtls/tls.c
+++ b/src/libtls/tls.c
@@ -107,6 +107,11 @@ struct private_tls_t {
 	tls_fragmentation_t *fragmentation;
 
 	/**
+	 * TLS alert handler
+	 */
+	tls_alert_t *alert;
+
+	/**
 	 * TLS crypto helper context
 	 */
 	tls_crypto_t *crypto;
@@ -159,6 +164,7 @@ METHOD(tls_t, set_version, bool,
 		case TLS_1_1:
 		case TLS_1_2:
 			this->version = version;
+			this->protection->set_version(this->protection, version);
 			return TRUE;
 		case SSL_2_0:
 		case SSL_3_0:
@@ -196,6 +202,7 @@ METHOD(tls_t, destroy, void,
 	this->peer->destroy(this->peer);
 	this->server->destroy(this->server);
 	DESTROY_IF(this->application);
+	this->alert->destroy(this->alert);
 
 	free(this);
 }
@@ -239,20 +246,21 @@ tls_t *tls_create(bool is_server, identification_t *server,
 	);
 
 	this->crypto = tls_crypto_create(&this->public);
+	this->alert = tls_alert_create();
 	if (is_server)
 	{
 		this->handshake = &tls_server_create(&this->public, this->crypto,
-									this->server, this->peer)->handshake;
+							this->alert, this->server, this->peer)->handshake;
 	}
 	else
 	{
 		this->handshake = &tls_peer_create(&this->public, this->crypto,
-									this->peer, this->server)->handshake;
+							this->alert, this->peer, this->server)->handshake;
 	}
-	this->fragmentation = tls_fragmentation_create(this->handshake,
+	this->fragmentation = tls_fragmentation_create(this->handshake, this->alert,
 												   this->application);
-	this->compression = tls_compression_create(this->fragmentation);
-	this->protection = tls_protection_create(&this->public, this->compression);
+	this->compression = tls_compression_create(this->fragmentation, this->alert);
+	this->protection = tls_protection_create(this->compression, this->alert);
 	this->crypto->set_protection(this->crypto, this->protection);
 
 	return &this->public;
diff --git a/src/libtls/tls_alert.c b/src/libtls/tls_alert.c
new file mode 100644
index 000000000..34f159e77
--- /dev/null
+++ b/src/libtls/tls_alert.c
@@ -0,0 +1,221 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "tls_alert.h"
+
+#include <debug.h>
+#include <utils/linked_list.h>
+
+ENUM_BEGIN(tls_alert_desc_names, TLS_CLOSE_NOTIFY, TLS_CLOSE_NOTIFY,
+	"close notify",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_UNEXPECTED_MESSAGE, TLS_UNEXPECTED_MESSAGE,
+		TLS_CLOSE_NOTIFY,
+	"unexpected message",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_BAD_RECORD_MAC, TLS_RECORD_OVERFLOW,
+		TLS_UNEXPECTED_MESSAGE,
+	"bad record mac",
+	"decryption failed",
+	"record overflow",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_DECOMPRESSION_FAILURE, TLS_DECOMPRESSION_FAILURE,
+		TLS_RECORD_OVERFLOW,
+	"decompression_failure",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_HANDSHAKE_FAILURE, TLS_DECRYPT_ERROR,
+		TLS_DECOMPRESSION_FAILURE,
+	"handshake failure",
+	"no certificate",
+	"bad certificate",
+	"unsupported certificate",
+	"certificate revoked",
+	"certificate expired",
+	"certificate unknown",
+	"illegal parameter",
+	"unknown ca",
+	"access denied",
+	"decode error",
+	"decrypt error",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_EXPORT_RESTRICTION, TLS_EXPORT_RESTRICTION,
+		TLS_DECRYPT_ERROR,
+	"export restriction",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_PROTOCOL_VERSION, TLS_INSUFFICIENT_SECURITY,
+		TLS_EXPORT_RESTRICTION,
+	"protocol version",
+	"insufficient security",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_INTERNAL_ERROR, TLS_INTERNAL_ERROR,
+		TLS_INSUFFICIENT_SECURITY,
+	"internal error",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_USER_CANCELED, TLS_USER_CANCELED,
+		TLS_INTERNAL_ERROR,
+	"user canceled",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_NO_RENEGOTIATION, TLS_NO_RENEGOTIATION,
+		TLS_USER_CANCELED,
+	"no renegotiation",
+);
+ENUM_NEXT(tls_alert_desc_names, TLS_UNSUPPORTED_EXTENSION, TLS_UNSUPPORTED_EXTENSION,
+		TLS_NO_RENEGOTIATION,
+	"unsupported extension",
+);
+ENUM_END(tls_alert_desc_names, TLS_UNSUPPORTED_EXTENSION);
+
+
+typedef struct private_tls_alert_t private_tls_alert_t;
+
+/**
+ * Private data of an tls_alert_t object.
+ */
+struct private_tls_alert_t {
+
+	/**
+	 * Public tls_alert_t interface.
+	 */
+	tls_alert_t public;
+
+	/**
+	 * Warning queue
+	 */
+	linked_list_t *warnings;
+
+	/**
+	 * Do we have a fatal alert?
+	 */
+	bool fatal;
+
+	/**
+	 * Has the fatal alert been consumed?
+	 */
+	bool consumed;
+
+	/**
+	 * Fatal alert discription
+	 */
+	tls_alert_desc_t desc;
+};
+
+METHOD(tls_alert_t, add, void,
+	private_tls_alert_t *this, tls_alert_level_t level,
+	tls_alert_desc_t desc)
+{
+	if (level == TLS_FATAL)
+	{
+		if (!this->fatal)
+		{
+			this->desc = desc;
+			this->fatal = TRUE;
+		}
+	}
+	else
+	{
+		this->warnings->insert_last(this->warnings, (void*)(uintptr_t)desc);
+	}
+}
+
+METHOD(tls_alert_t, get, bool,
+	private_tls_alert_t *this, tls_alert_level_t *level,
+	tls_alert_desc_t *desc)
+{
+	if (this->fatal && !this->consumed)
+	{
+		this->consumed = TRUE;
+		*level = TLS_FATAL;
+		*desc = this->desc;
+		DBG1(DBG_TLS, "sending fatal TLS alert '%N'",
+			 tls_alert_desc_names, this->desc);
+		return TRUE;
+	}
+	else
+	{
+		uintptr_t warning;
+
+		if (this->warnings->remove_first(this->warnings,
+										 (void**)&warning) == SUCCESS)
+		{
+			*level = TLS_WARNING;
+			*desc = warning;
+			DBG1(DBG_TLS, "sending TLS alert warning '%N'",
+				 tls_alert_desc_names, warning);
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+
+METHOD(tls_alert_t, fatal, bool,
+	private_tls_alert_t *this)
+{
+	return this->fatal;
+}
+
+METHOD(tls_alert_t, process, status_t,
+	private_tls_alert_t *this, tls_alert_level_t level,
+	tls_alert_desc_t desc)
+{
+	if (desc == TLS_CLOSE_NOTIFY)
+	{
+		DBG1(DBG_TLS, "received TLS close notify");
+		add(this, TLS_FATAL, TLS_CLOSE_NOTIFY);
+		return NEED_MORE;
+	}
+	switch (level)
+	{
+		case TLS_WARNING:
+			DBG1(DBG_TLS, "received TLS alert warning '%N'",
+				 tls_alert_desc_names, desc);
+			return NEED_MORE;
+		case TLS_FATAL:
+			DBG1(DBG_TLS, "received fatal TLS alert '%N'",
+				 tls_alert_desc_names, desc);
+			return FAILED;
+		default:
+			DBG1(DBG_TLS, "received unknown TLS alert '%N'",
+				 tls_alert_desc_names, desc);
+			return FAILED;
+	}
+}
+
+METHOD(tls_alert_t, destroy, void,
+	private_tls_alert_t *this)
+{
+	this->warnings->destroy(this->warnings);
+	free(this);
+}
+
+/**
+ * See header
+ */
+tls_alert_t *tls_alert_create()
+{
+	private_tls_alert_t *this;
+
+	INIT(this,
+		.public = {
+			.add = _add,
+			.get = _get,
+			.fatal = _fatal,
+			.process = _process,
+			.destroy = _destroy,
+		},
+		.warnings = linked_list_create(),
+	);
+
+	return &this->public;
+}
diff --git a/src/libtls/tls_alert.h b/src/libtls/tls_alert.h
new file mode 100644
index 000000000..95ba4d91b
--- /dev/null
+++ b/src/libtls/tls_alert.h
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup tls_alert tls_alert
+ * @{ @ingroup libtls
+ */
+
+#ifndef TLS_ALERT_H_
+#define TLS_ALERT_H_
+
+#include <library.h>
+
+typedef struct tls_alert_t tls_alert_t;
+typedef enum tls_alert_level_t tls_alert_level_t;
+typedef enum tls_alert_desc_t tls_alert_desc_t;
+
+/**
+ * Level of a TLS alert
+ */
+enum tls_alert_level_t {
+	TLS_WARNING = 1,
+	TLS_FATAL = 2,
+};
+
+/**
+ * Description of a TLS alert
+ */
+enum tls_alert_desc_t {
+	TLS_CLOSE_NOTIFY = 0,
+	TLS_UNEXPECTED_MESSAGE = 10,
+	TLS_BAD_RECORD_MAC = 20,
+	TLS_DECRYPTION_FAILED = 21,
+	TLS_RECORD_OVERFLOW = 22,
+	TLS_DECOMPRESSION_FAILURE = 30,
+	TLS_HANDSHAKE_FAILURE = 40,
+	TLS_NO_CERTIFICATE = 41,
+	TLS_BAD_CERTIFICATE = 42,
+	TLS_UNSUPPORTED_CERTIFICATE = 43,
+	TLS_CERTIFICATE_REVOKED = 44,
+	TLS_CERTIFICATE_EXPIRED = 45,
+	TLS_CERTIFICATE_UNKNOWN = 46,
+	TLS_ILLEGAL_PARAMETER = 47,
+	TLS_UNKNOWN_CA = 48,
+	TLS_ACCESS_DENIED = 49,
+	TLS_DECODE_ERROR = 50,
+	TLS_DECRYPT_ERROR = 51,
+	TLS_EXPORT_RESTRICTION = 60,
+	TLS_PROTOCOL_VERSION = 70,
+	TLS_INSUFFICIENT_SECURITY = 71,
+	TLS_INTERNAL_ERROR = 80,
+	TLS_USER_CANCELED = 90,
+	TLS_NO_RENEGOTIATION = 100,
+	TLS_UNSUPPORTED_EXTENSION = 110,
+};
+
+/**
+ * Enum names for alert descriptions
+ */
+extern enum_name_t *tls_alert_desc_names;
+
+/**
+ * TLS alert handling.
+ */
+struct tls_alert_t {
+
+	/**
+	 * Add an alert to the TLS alert queue, will be sent.
+	 *
+	 * @param level			level of TLS alert
+	 * @param description	description of alert
+	 */
+	void (*add)(tls_alert_t *this, tls_alert_level_t level,
+				tls_alert_desc_t description);
+
+	/**
+	 * Get an alert pushed to the alert queue, to send.
+	 *
+	 * @param level			receives TLS alert level
+	 * @param description	receives TLS alert description
+	 * @return				TRUE if returned an alert
+	 */
+	bool (*get)(tls_alert_t *this, tls_alert_level_t *level,
+				tls_alert_desc_t *description);
+
+	/**
+	 * Did a fatal alert occur?.
+	 *
+	 * @return				TRUE if a fatal alert has occured
+	 */
+	bool (*fatal)(tls_alert_t *this);
+
+	/**
+	 * Process a received TLS alert.
+	 *
+	 * @param level			level of received alert
+	 * @param description	alert description
+	 * @return				status to pass down to TLS stack
+	 */
+	status_t (*process)(tls_alert_t *this, tls_alert_level_t level,
+						tls_alert_desc_t description);
+
+	/**
+	 * Destroy a tls_alert_t.
+	 */
+	void (*destroy)(tls_alert_t *this);
+};
+
+/**
+ * Create a tls_alert instance.
+ */
+tls_alert_t *tls_alert_create();
+
+#endif /** TLS_ALERT_H_ @}*/
diff --git a/src/libtls/tls_compression.c b/src/libtls/tls_compression.c
index 02a3578e3..68266cd0c 100644
--- a/src/libtls/tls_compression.c
+++ b/src/libtls/tls_compression.c
@@ -54,7 +54,8 @@ METHOD(tls_compression_t, destroy, void,
 /**
  * See header
  */
-tls_compression_t *tls_compression_create(tls_fragmentation_t *fragmentation)
+tls_compression_t *tls_compression_create(tls_fragmentation_t *fragmentation,
+										  tls_alert_t *alert)
 {
 	private_tls_compression_t *this;
 
diff --git a/src/libtls/tls_compression.h b/src/libtls/tls_compression.h
index bd27ab5d7..b4832ab06 100644
--- a/src/libtls/tls_compression.h
+++ b/src/libtls/tls_compression.h
@@ -21,13 +21,14 @@
 #ifndef TLS_COMPRESSION_H_
 #define TLS_COMPRESSION_H_
 
-typedef struct tls_compression_t tls_compression_t;
-
 #include <library.h>
 
 #include "tls.h"
+#include "tls_alert.h"
 #include "tls_fragmentation.h"
 
+typedef struct tls_compression_t tls_compression_t;
+
 /**
  * TLS record protocol compression layer.
  */
@@ -70,8 +71,10 @@ struct tls_compression_t {
  * Create a tls_compression instance.
  *
  * @param fragmentation		fragmentation layer of TLS stack
+ * @param alert				TLS alert handler
  * @return					TLS compression layer.
  */
-tls_compression_t *tls_compression_create(tls_fragmentation_t *fragmentation);
+tls_compression_t *tls_compression_create(tls_fragmentation_t *fragmentation,
+										  tls_alert_t *alert);
 
 #endif /** TLS_COMPRESSION_H_ @}*/
diff --git a/src/libtls/tls_fragmentation.c b/src/libtls/tls_fragmentation.c
index 06e1bcb53..d69ef3901 100644
--- a/src/libtls/tls_fragmentation.c
+++ b/src/libtls/tls_fragmentation.c
@@ -22,6 +22,18 @@
 typedef struct private_tls_fragmentation_t private_tls_fragmentation_t;
 
 /**
+ * Alert state
+ */
+typedef enum {
+	/* no alert received/sent */
+	ALERT_NONE,
+	/* currently sending an alert */
+	ALERT_SENDING,
+	/* alert sent and out */
+	ALERT_SENT,
+} alert_state_t;
+
+/**
  * Private data of an tls_fragmentation_t object.
  */
 struct private_tls_fragmentation_t {
@@ -37,6 +49,16 @@ struct private_tls_fragmentation_t {
 	tls_handshake_t *handshake;
 
 	/**
+	 * TLS alert handler
+	 */
+	tls_alert_t *alert;
+
+	/**
+	 * State of alert handling
+	 */
+	alert_state_t state;
+
+	/**
 	 * Handshake input buffer
 	 */
 	chunk_t input;
@@ -73,6 +95,23 @@ struct private_tls_fragmentation_t {
 #define MAX_TLS_HANDSHAKE_LEN 65536
 
 /**
+ * Process a TLS alert
+ */
+static status_t process_alert(private_tls_fragmentation_t *this,
+							  tls_reader_t *reader)
+{
+	u_int8_t level, description;
+
+	if (!reader->read_uint8(reader, &level) ||
+		!reader->read_uint8(reader, &description))
+	{
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
+	}
+	return this->alert->process(this->alert, level, description);
+}
+
+/**
  * Process TLS handshake protocol data
  */
 static status_t process_handshake(private_tls_fragmentation_t *this,
@@ -89,7 +128,8 @@ static status_t process_handshake(private_tls_fragmentation_t *this,
 		if (reader->remaining(reader) > MAX_TLS_FRAGMENT_LEN)
 		{
 			DBG1(DBG_TLS, "TLS fragment has invalid length");
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+			return NEED_MORE;
 		}
 
 		if (this->input.len == 0)
@@ -97,13 +137,16 @@ static status_t process_handshake(private_tls_fragmentation_t *this,
 			if (!reader->read_uint8(reader, &type) ||
 				!reader->read_uint24(reader, &len))
 			{
-				return FAILED;
+				DBG1(DBG_TLS, "TLS handshake header invalid");
+				this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+				return NEED_MORE;
 			}
 			this->type = type;
 			if (len > MAX_TLS_HANDSHAKE_LEN)
 			{
 				DBG1(DBG_TLS, "TLS handshake message exceeds maximum length");
-				return FAILED;
+				this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+				return NEED_MORE;
 			}
 			chunk_free(&this->input);
 			this->inpos = 0;
@@ -116,7 +159,9 @@ static status_t process_handshake(private_tls_fragmentation_t *this,
 		len = min(this->input.len - this->inpos, reader->remaining(reader));
 		if (!reader->read_data(reader, len, &data))
 		{
-			return FAILED;
+			DBG1(DBG_TLS, "TLS fragment has invalid length");
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+			return NEED_MORE;
 		}
 		memcpy(this->input.ptr + this->inpos, data.ptr, len);
 		this->inpos += len;
@@ -151,12 +196,14 @@ static status_t process_application(private_tls_fragmentation_t *this,
 		if (reader->remaining(reader) > MAX_TLS_FRAGMENT_LEN)
 		{
 			DBG1(DBG_TLS, "TLS fragment has invalid length");
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+			return NEED_MORE;
 		}
 		status = this->application->process(this->application, reader);
 		if (status != NEED_MORE)
 		{
-			return status;
+			this->alert->add(this->alert, TLS_FATAL, TLS_CLOSE_NOTIFY);
+			return NEED_MORE;
 		}
 	}
 	return NEED_MORE;
@@ -168,6 +215,15 @@ METHOD(tls_fragmentation_t, process, status_t,
 	tls_reader_t *reader;
 	status_t status;
 
+	switch (this->state)
+	{
+		case ALERT_SENDING:
+		case ALERT_SENT:
+			/* don't accept more input, fatal error ocurred */
+			return NEED_MORE;
+		case ALERT_NONE:
+			break;
+	}
 	reader = tls_reader_create(data);
 	switch (type)
 	{
@@ -180,8 +236,7 @@ METHOD(tls_fragmentation_t, process, status_t,
 			status = FAILED;
 			break;
 		case TLS_ALERT:
-			/* TODO: handle Alert */
-			status = FAILED;
+			status = process_alert(this, reader);
 			break;
 		case TLS_HANDSHAKE:
 			status = process_handshake(this, reader);
@@ -198,6 +253,29 @@ METHOD(tls_fragmentation_t, process, status_t,
 	return status;
 }
 
+/**
+ * Check if alerts are pending
+ */
+static bool check_alerts(private_tls_fragmentation_t *this, chunk_t *data)
+{
+	tls_alert_level_t level;
+	tls_alert_desc_t desc;
+	tls_writer_t *writer;
+
+	if (this->alert->get(this->alert, &level, &desc))
+	{
+		writer = tls_writer_create(2);
+
+		writer->write_uint8(writer, level);
+		writer->write_uint8(writer, desc);
+
+		*data = chunk_clone(writer->get_buf(writer));
+		writer->destroy(writer);
+		return TRUE;
+	}
+	return FALSE;
+}
+
 METHOD(tls_fragmentation_t, build, status_t,
 	private_tls_fragmentation_t *this, tls_content_type_t *type, chunk_t *data)
 {
@@ -206,6 +284,22 @@ METHOD(tls_fragmentation_t, build, status_t,
 	tls_writer_t *writer, *msg;
 	status_t status = INVALID_STATE;
 
+	switch (this->state)
+	{
+		case ALERT_SENDING:
+			this->state = ALERT_SENT;
+			return INVALID_STATE;
+		case ALERT_SENT:
+			return FAILED;
+		case ALERT_NONE:
+			break;
+	}
+	if (check_alerts(this, data))
+	{
+		this->state = ALERT_SENDING;
+		*type = TLS_ALERT;
+		return NEED_MORE;
+	}
 	if (this->handshake->cipherspec_changed(this->handshake))
 	{
 		*type = TLS_CHANGE_CIPHER_SPEC;
@@ -227,6 +321,16 @@ METHOD(tls_fragmentation_t, build, status_t,
 					*type = TLS_APPLICATION_DATA;
 					this->output = chunk_clone(msg->get_buf(msg));
 				}
+				else if (status != NEED_MORE)
+				{
+					this->alert->add(this->alert, TLS_FATAL, TLS_CLOSE_NOTIFY);
+					if (check_alerts(this, data))
+					{
+						this->state = ALERT_SENDING;
+						*type = TLS_ALERT;
+						return NEED_MORE;
+					}
+				}
 			}
 		}
 		else
@@ -290,7 +394,7 @@ METHOD(tls_fragmentation_t, destroy, void,
  * See header
  */
 tls_fragmentation_t *tls_fragmentation_create(tls_handshake_t *handshake,
-											  tls_application_t *application)
+							tls_alert_t *alert, tls_application_t *application)
 {
 	private_tls_fragmentation_t *this;
 
@@ -301,6 +405,8 @@ tls_fragmentation_t *tls_fragmentation_create(tls_handshake_t *handshake,
 			.destroy = _destroy,
 		},
 		.handshake = handshake,
+		.alert = alert,
+		.state = ALERT_NONE,
 		.application = application,
 	);
 
diff --git a/src/libtls/tls_fragmentation.h b/src/libtls/tls_fragmentation.h
index 6adbc36d0..699244595 100644
--- a/src/libtls/tls_fragmentation.h
+++ b/src/libtls/tls_fragmentation.h
@@ -21,13 +21,13 @@
 #ifndef TLS_FRAGMENTATION_H_
 #define TLS_FRAGMENTATION_H_
 
-typedef struct tls_fragmentation_t tls_fragmentation_t;
-
 #include <library.h>
 
 #include "tls.h"
+#include "tls_alert.h"
 #include "tls_handshake.h"
-#include "tls_handshake.h"
+
+typedef struct tls_fragmentation_t tls_fragmentation_t;
 
 /**
  * TLS record protocol fragmentation layer.
@@ -71,10 +71,11 @@ struct tls_fragmentation_t {
  * Create a tls_fragmentation instance.
  *
  * @param handshake			upper layer handshake protocol
+ * @param alert				TLS alert handler
  * @param application		upper layer application data or NULL
- * @return					TLS fragmentation layer.
+ * @return					TLS fragmentation layer
  */
 tls_fragmentation_t *tls_fragmentation_create(tls_handshake_t *handshake,
-											  tls_application_t *application);
+							tls_alert_t *alert, tls_application_t *application);
 
 #endif /** TLS_FRAGMENTATION_H_ @}*/
diff --git a/src/libtls/tls_handshake.h b/src/libtls/tls_handshake.h
index 3aab3c527..6703b341b 100644
--- a/src/libtls/tls_handshake.h
+++ b/src/libtls/tls_handshake.h
@@ -38,9 +38,10 @@ struct tls_handshake_t {
 	 * @param type		TLS handshake message type
 	 * @param reader	TLS data buffer
 	 * @return
-	 *					- SUCCESS if handshake complete
-	 *					- FAILED if handshake failed
-	 *					- NEED_MORE if another invocation of process/build needed
+	 *					- SUCCESS if TLS negotiation complete
+	 *					- FAILED if a fatal TLS alert queued
+	 *					- NEED_MORE if more invocations to process/build needed
+	 *					- DESTROY_ME if a fatal TLS alert received
 	 */
 	status_t (*process)(tls_handshake_t *this,
 						tls_handshake_type_t type, tls_reader_t *reader);
diff --git a/src/libtls/tls_peer.c b/src/libtls/tls_peer.c
index ddd117a87..a08e411c7 100644
--- a/src/libtls/tls_peer.c
+++ b/src/libtls/tls_peer.c
@@ -58,6 +58,11 @@ struct private_tls_peer_t {
 	tls_crypto_t *crypto;
 
 	/**
+	 * TLS alert handler
+	 */
+	tls_alert_t *alert;
+
+	/**
 	 * Peer identity
 	 */
 	identification_t *peer;
@@ -125,7 +130,8 @@ static status_t process_server_hello(private_tls_peer_t *this,
 		(reader->remaining(reader) && !reader->read_data16(reader, &ext)))
 	{
 		DBG1(DBG_TLS, "received invalid ServerHello");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 
 	memcpy(this->server_random, random.ptr, sizeof(this->server_random));
@@ -134,14 +140,16 @@ static status_t process_server_hello(private_tls_peer_t *this,
 	{
 		DBG1(DBG_TLS, "negotiated version %N not supported",
 			 tls_version_names, version);
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_PROTOCOL_VERSION);
+		return NEED_MORE;
 	}
 	suite = cipher;
 	if (!this->crypto->select_cipher_suite(this->crypto, &suite, 1))
 	{
 		DBG1(DBG_TLS, "received TLS cipher suite %N inacceptable",
 			 tls_cipher_suite_names, suite);
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_HANDSHAKE_FAILURE);
+		return NEED_MORE;
 	}
 	DBG1(DBG_TLS, "negotiated TLS version %N with suite %N",
 		 tls_version_names, version, tls_cipher_suite_names, suite);
@@ -165,15 +173,19 @@ static status_t process_certificate(private_tls_peer_t *this,
 
 	if (!reader->read_data24(reader, &data))
 	{
-		return FAILED;
+		DBG1(DBG_TLS, "certificate message header invalid");
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 	certs = tls_reader_create(data);
 	while (certs->remaining(certs))
 	{
 		if (!certs->read_data24(certs, &data))
 		{
+			DBG1(DBG_TLS, "certificate message invalid");
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
 			certs->destroy(certs);
-			return FAILED;
+			return NEED_MORE;
 		}
 		cert = lib->creds->create(lib->creds, CRED_CERTIFICATE, CERT_X509,
 								  BUILD_BLOB_ASN1_DER, data, BUILD_END);
@@ -198,6 +210,7 @@ static status_t process_certificate(private_tls_peer_t *this,
 		else
 		{
 			DBG1(DBG_TLS, "parsing TLS certificate failed, skipped");
+			this->alert->add(this->alert, TLS_WARNING, TLS_BAD_CERTIFICATE);
 		}
 	}
 	certs->destroy(certs);
@@ -220,27 +233,35 @@ static status_t process_certreq(private_tls_peer_t *this, tls_reader_t *reader)
 
 	if (!reader->read_data8(reader, &types))
 	{
-		return FAILED;
+		DBG1(DBG_TLS, "certreq message header invalid");
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 	if (this->tls->get_version(this->tls) >= TLS_1_2)
 	{
 		if (!reader->read_data16(reader, &hashsig))
 		{
-			return FAILED;
+			DBG1(DBG_TLS, "certreq message invalid");
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+			return NEED_MORE;
 		}
 		/* TODO: store supported hashsig algorithms */
 	}
 	if (!reader->read_data16(reader, &data))
 	{
-		return FAILED;
+		DBG1(DBG_TLS, "certreq message invalid");
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 	authorities = tls_reader_create(data);
 	while (authorities->remaining(authorities))
 	{
 		if (!authorities->read_data16(authorities, &data))
 		{
+			DBG1(DBG_TLS, "certreq message invalid");
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
 			authorities->destroy(authorities);
-			return FAILED;
+			return NEED_MORE;
 		}
 		id = identification_create_from_encoding(ID_DER_ASN1_DN, data);
 		cert = lib->credmgr->get_cert(lib->credmgr,
@@ -284,17 +305,20 @@ static status_t process_finished(private_tls_peer_t *this, tls_reader_t *reader)
 	if (!reader->read_data(reader, sizeof(buf), &received))
 	{
 		DBG1(DBG_TLS, "received server finished too short");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 	if (!this->crypto->calculate_finished(this->crypto, "server finished", buf))
 	{
 		DBG1(DBG_TLS, "calculating server finished failed");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		return NEED_MORE;
 	}
 	if (!chunk_equals(received, chunk_from_thing(buf)))
 	{
 		DBG1(DBG_TLS, "received server finished invalid");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECRYPT_ERROR);
+		return NEED_MORE;
 	}
 	this->state = STATE_COMPLETE;
 	this->crypto->derive_eap_msk(this->crypto,
@@ -348,11 +372,13 @@ METHOD(tls_handshake_t, process, status_t,
 		default:
 			DBG1(DBG_TLS, "TLS %N not expected in current state",
 				 tls_handshake_type_names, type);
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_UNEXPECTED_MESSAGE);
+			return NEED_MORE;
 	}
 	DBG1(DBG_TLS, "TLS %N expected, but received %N",
 		 tls_handshake_type_names, expected, tls_handshake_type_names, type);
-	return FAILED;
+	this->alert->add(this->alert, TLS_FATAL, TLS_UNEXPECTED_MESSAGE);
+	return NEED_MORE;
 }
 
 /**
@@ -370,7 +396,9 @@ static status_t send_client_hello(private_tls_peer_t *this,
 	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
 	if (!rng)
 	{
-		return FAILED;
+		DBG1(DBG_TLS, "no suitable RNG found to generate client random");
+		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		return NEED_MORE;
 	}
 	rng->get_bytes(rng, sizeof(this->client_random) - 4, this->client_random + 4);
 	rng->destroy(rng);
@@ -420,7 +448,8 @@ static status_t send_certificate(private_tls_peer_t *this,
 	if (!this->private)
 	{
 		DBG1(DBG_TLS, "no TLS peer certificate found for '%Y'", this->peer);
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		return NEED_MORE;
 	}
 
 	/* generate certificate payload */
@@ -640,7 +669,7 @@ METHOD(tls_handshake_t, destroy, void,
 /**
  * See header
  */
-tls_peer_t *tls_peer_create(tls_t *tls, tls_crypto_t *crypto,
+tls_peer_t *tls_peer_create(tls_t *tls, tls_crypto_t *crypto, tls_alert_t *alert,
 							identification_t *peer, identification_t *server)
 {
 	private_tls_peer_t *this;
@@ -659,6 +688,7 @@ tls_peer_t *tls_peer_create(tls_t *tls, tls_crypto_t *crypto,
 		.state = STATE_INIT,
 		.tls = tls,
 		.crypto = crypto,
+		.alert = alert,
 		.peer = peer,
 		.server = server,
 		.peer_auth = auth_cfg_create(),
diff --git a/src/libtls/tls_peer.h b/src/libtls/tls_peer.h
index eb97c97e4..f773ea72e 100644
--- a/src/libtls/tls_peer.h
+++ b/src/libtls/tls_peer.h
@@ -41,8 +41,14 @@ struct tls_peer_t {
 
 /**
  * Create a tls_peer instance.
+*
+ * @param tls		TLS stack
+ * @param crypto	TLS crypto helper
+ * @param alert		TLS alert handler
+ * @param peer		peer identity
+ * @param server	server identity
  */
-tls_peer_t *tls_peer_create(tls_t *tls, tls_crypto_t *crypto,
+tls_peer_t *tls_peer_create(tls_t *tls, tls_crypto_t *crypto, tls_alert_t *alert,
 							identification_t *peer, identification_t *server);
 
 #endif /** TLS_PEER_H_ @}*/
diff --git a/src/libtls/tls_protection.c b/src/libtls/tls_protection.c
index 90b30f99b..574e69167 100644
--- a/src/libtls/tls_protection.c
+++ b/src/libtls/tls_protection.c
@@ -30,9 +30,9 @@ struct private_tls_protection_t {
 	tls_protection_t public;
 
 	/**
-	 * TLS context
+	 * negotiated TLS version
 	 */
-	tls_t *tls;
+	tls_version_t version;
 
 	/**
 	 * Upper layer, TLS record compression
@@ -40,6 +40,11 @@ struct private_tls_protection_t {
 	tls_compression_t *compression;
 
 	/**
+	 * TLS alert handler
+	 */
+	tls_alert_t *alert;
+
+	/**
 	 * RNG if we generate IVs ourself
 	 */
 	rng_t *rng;
@@ -106,6 +111,11 @@ static chunk_t sigheader(u_int32_t seq, u_int8_t type,
 METHOD(tls_protection_t, process, status_t,
 	private_tls_protection_t *this, tls_content_type_t type, chunk_t data)
 {
+	if (this->alert->fatal(this->alert))
+	{	/* don't accept more input, fatal error ocurred */
+		return NEED_MORE;
+	}
+
 	if (this->crypter_in)
 	{
 		chunk_t iv, next_iv = chunk_empty;
@@ -117,7 +127,8 @@ METHOD(tls_protection_t, process, status_t,
 			if (data.len < bs || data.len % bs)
 			{
 				DBG1(DBG_TLS, "encrypted TLS record length invalid");
-				return FAILED;
+				this->alert->add(this->alert, TLS_FATAL, TLS_BAD_RECORD_MAC);
+				return NEED_MORE;
 			}
 			iv = this->iv_in;
 			next_iv = chunk_clone(chunk_create(data.ptr + data.len - bs, bs));
@@ -130,7 +141,8 @@ METHOD(tls_protection_t, process, status_t,
 			if (data.len < bs || data.len % bs)
 			{
 				DBG1(DBG_TLS, "encrypted TLS record length invalid");
-				return FAILED;
+				this->alert->add(this->alert, TLS_FATAL, TLS_BAD_RECORD_MAC);
+				return NEED_MORE;
 			}
 		}
 		this->crypter_in->decrypt(this->crypter_in, data, iv, NULL);
@@ -145,7 +157,8 @@ METHOD(tls_protection_t, process, status_t,
 		if (padding_length >= data.len)
 		{
 			DBG1(DBG_TLS, "invalid TLS record padding");
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_BAD_RECORD_MAC);
+			return NEED_MORE;
 		}
 		data.len -= padding_length + 1;
 	}
@@ -158,19 +171,20 @@ METHOD(tls_protection_t, process, status_t,
 		if (data.len <= bs)
 		{
 			DBG1(DBG_TLS, "TLS record too short to verify MAC");
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_BAD_RECORD_MAC);
+			return NEED_MORE;
 		}
 		mac = chunk_skip(data, data.len - bs);
 		data.len -= bs;
 
-		header = sigheader(this->seq_in, type,
-						   this->tls->get_version(this->tls), data.len);
+		header = sigheader(this->seq_in, type, this->version, data.len);
 		macdata = chunk_cat("mc", header, data);
 		if (!this->signer_in->verify_signature(this->signer_in, macdata, mac))
 		{
 			DBG1(DBG_TLS, "TLS record MAC verification failed");
 			free(macdata.ptr);
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_BAD_RECORD_MAC);
+			return NEED_MORE;
 		}
 		free(macdata.ptr);
 	}
@@ -204,8 +218,7 @@ METHOD(tls_protection_t, build, status_t,
 		{
 			chunk_t mac, header;
 
-			header = sigheader(this->seq_out, *type,
-							   this->tls->get_version(this->tls), data->len);
+			header = sigheader(this->seq_out, *type, this->version, data->len);
 			this->signer_out->get_signature(this->signer_out, header, NULL);
 			free(header.ptr);
 			this->signer_out->allocate_signature(this->signer_out, *data, &mac);
@@ -283,6 +296,12 @@ METHOD(tls_protection_t, set_cipher, void,
 	}
 }
 
+METHOD(tls_protection_t, set_version, void,
+	private_tls_protection_t *this, tls_version_t version)
+{
+	this->version = version;
+}
+
 METHOD(tls_protection_t, destroy, void,
 	private_tls_protection_t *this)
 {
@@ -293,8 +312,8 @@ METHOD(tls_protection_t, destroy, void,
 /**
  * See header
  */
-tls_protection_t *tls_protection_create(tls_t *tls,
-										tls_compression_t *compression)
+tls_protection_t *tls_protection_create(tls_compression_t *compression,
+										tls_alert_t *alert)
 {
 	private_tls_protection_t *this;
 
@@ -303,9 +322,10 @@ tls_protection_t *tls_protection_create(tls_t *tls,
 			.process = _process,
 			.build = _build,
 			.set_cipher = _set_cipher,
+			.set_version = _set_version,
 			.destroy = _destroy,
 		},
-		.tls = tls,
+		.alert = alert,
 		.compression = compression,
 	);
 
diff --git a/src/libtls/tls_protection.h b/src/libtls/tls_protection.h
index aa7681bd5..99c94e935 100644
--- a/src/libtls/tls_protection.h
+++ b/src/libtls/tls_protection.h
@@ -21,13 +21,14 @@
 #ifndef TLS_PROTECTION_H_
 #define TLS_PROTECTION_H_
 
-typedef struct tls_protection_t tls_protection_t;
-
 #include <library.h>
 
 #include "tls.h"
+#include "tls_alert.h"
 #include "tls_compression.h"
 
+typedef struct tls_protection_t tls_protection_t;
+
 /**
  * TLS record protocol protection layer.
  */
@@ -72,6 +73,13 @@ struct tls_protection_t {
 					   crypter_t *crypter, chunk_t iv);
 
 	/**
+	 * Set the TLS version negotiated, used for MAC calculation.
+	 *
+	 * @param version	TLS version negotiated
+	 */
+	void (*set_version)(tls_protection_t *this, tls_version_t version);
+
+	/**
 	 * Destroy a tls_protection_t.
 	 */
 	void (*destroy)(tls_protection_t *this);
@@ -80,11 +88,11 @@ struct tls_protection_t {
 /**
  * Create a tls_protection instance.
  *
- * @param tls				TLS context
  * @param compression		compression layer of TLS stack
+ * @param alert				TLS alert handler
  * @return					TLS protection layer.
  */
-tls_protection_t *tls_protection_create(tls_t *tls,
-										tls_compression_t *compression);
+tls_protection_t *tls_protection_create(tls_compression_t *compression,
+										tls_alert_t *alert);
 
 #endif /** TLS_PROTECTION_H_ @}*/
diff --git a/src/libtls/tls_server.c b/src/libtls/tls_server.c
index 3248a0c1a..4f988c603 100644
--- a/src/libtls/tls_server.c
+++ b/src/libtls/tls_server.c
@@ -60,6 +60,11 @@ struct private_tls_server_t {
 	tls_crypto_t *crypto;
 
 	/**
+	 * TLS alert handler
+	 */
+	tls_alert_t *alert;
+
+	/**
 	 * Server identity
 	 */
 	identification_t *server;
@@ -132,7 +137,8 @@ static status_t process_client_hello(private_tls_server_t *this,
 		(reader->remaining(reader) && !reader->read_data16(reader, &ext)))
 	{
 		DBG1(DBG_TLS, "received invalid ClientHello");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 
 	memcpy(this->client_random, random.ptr, sizeof(this->client_random));
@@ -141,7 +147,8 @@ static status_t process_client_hello(private_tls_server_t *this,
 	{
 		DBG1(DBG_TLS, "negotiated version %N not supported",
 			 tls_version_names, version);
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_PROTOCOL_VERSION);
+		return NEED_MORE;
 	}
 	count = ciphers.len / sizeof(u_int16_t);
 	suites = alloca(count * sizeof(tls_cipher_suite_t));
@@ -155,7 +162,8 @@ static status_t process_client_hello(private_tls_server_t *this,
 	if (!this->suite)
 	{
 		DBG1(DBG_TLS, "received cipher suites inacceptable");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_HANDSHAKE_FAILURE);
+		return NEED_MORE;
 	}
 	DBG1(DBG_TLS, "negotiated TLS version %N with suite %N",
 		 tls_version_names, version, tls_cipher_suite_names, this->suite);
@@ -179,15 +187,19 @@ static status_t process_certificate(private_tls_server_t *this,
 
 	if (!reader->read_data24(reader, &data))
 	{
-		return FAILED;
+		DBG1(DBG_TLS, "certificate message header invalid");
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 	certs = tls_reader_create(data);
 	while (certs->remaining(certs))
 	{
 		if (!certs->read_data24(certs, &data))
 		{
+			DBG1(DBG_TLS, "certificate message invalid");
+			this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
 			certs->destroy(certs);
-			return FAILED;
+			return NEED_MORE;
 		}
 		cert = lib->creds->create(lib->creds, CRED_CERTIFICATE, CERT_X509,
 								  BUILD_BLOB_ASN1_DER, data, BUILD_END);
@@ -211,6 +223,7 @@ static status_t process_certificate(private_tls_server_t *this,
 		else
 		{
 			DBG1(DBG_TLS, "parsing TLS certificate failed, skipped");
+			this->alert->add(this->alert, TLS_WARNING, TLS_BAD_CERTIFICATE);
 		}
 	}
 	certs->destroy(certs);
@@ -232,7 +245,8 @@ static status_t process_key_exchange(private_tls_server_t *this,
 	if (!reader->read_data16(reader, &encrypted))
 	{
 		DBG1(DBG_TLS, "received invalid Client Key Exchange");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 
 	if (!this->private ||
@@ -240,7 +254,8 @@ static status_t process_key_exchange(private_tls_server_t *this,
 								encrypted, &premaster))
 	{
 		DBG1(DBG_TLS, "decrypting Client Key Exchange data failed");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECRYPT_ERROR);
+		return NEED_MORE;
 	}
 	this->crypto->derive_secrets(this->crypto, premaster,
 								 chunk_from_thing(this->client_random),
@@ -282,7 +297,8 @@ static status_t process_cert_verify(private_tls_server_t *this,
 	{
 		DBG1(DBG_TLS, "no trusted certificate found for '%Y' to verify TLS peer",
 			 this->peer);
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_CERTIFICATE_UNKNOWN);
+		return NEED_MORE;
 	}
 
 	this->crypto->append_handshake(this->crypto,
@@ -303,17 +319,20 @@ static status_t process_finished(private_tls_server_t *this,
 	if (!reader->read_data(reader, sizeof(buf), &received))
 	{
 		DBG1(DBG_TLS, "received client finished too short");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECODE_ERROR);
+		return NEED_MORE;
 	}
 	if (!this->crypto->calculate_finished(this->crypto, "client finished", buf))
 	{
 		DBG1(DBG_TLS, "calculating client finished failed");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		return NEED_MORE;
 	}
 	if (!chunk_equals(received, chunk_from_thing(buf)))
 	{
 		DBG1(DBG_TLS, "received client finished invalid");
-		return FAILED;
+		this->alert->add(this->alert, TLS_FATAL, TLS_DECRYPT_ERROR);
+		return NEED_MORE;
 	}
 
 	this->crypto->append_handshake(this->crypto, TLS_FINISHED, received);
@@ -377,11 +396,13 @@ METHOD(tls_handshake_t, process, status_t,
 		default:
 			DBG1(DBG_TLS, "TLS %N not expected in current state",
 				 tls_handshake_type_names, type);
-			return FAILED;
+			this->alert->add(this->alert, TLS_FATAL, TLS_UNEXPECTED_MESSAGE);
+			return NEED_MORE;
 	}
 	DBG1(DBG_TLS, "TLS %N expected, but received %N",
 		 tls_handshake_type_names, expected, tls_handshake_type_names, type);
-	return FAILED;
+	this->alert->add(this->alert, TLS_FATAL, TLS_UNEXPECTED_MESSAGE);
+	return NEED_MORE;
 }
 
 /**
@@ -397,6 +418,7 @@ static status_t send_server_hello(private_tls_server_t *this,
 	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
 	if (!rng)
 	{
+		DBG1(DBG_TLS, "no suitable RNG found to generate server random");
 		return FAILED;
 	}
 	rng->get_bytes(rng, sizeof(this->server_random) - 4, this->server_random + 4);
@@ -630,8 +652,9 @@ METHOD(tls_handshake_t, destroy, void,
 /**
  * See header
  */
-tls_server_t *tls_server_create(tls_t *tls, tls_crypto_t *crypto,
-							identification_t *server, identification_t *peer)
+tls_server_t *tls_server_create(tls_t *tls,
+						tls_crypto_t *crypto, tls_alert_t *alert,
+						identification_t *server, identification_t *peer)
 {
 	private_tls_server_t *this;
 
@@ -648,6 +671,7 @@ tls_server_t *tls_server_create(tls_t *tls, tls_crypto_t *crypto,
 		},
 		.tls = tls,
 		.crypto = crypto,
+		.alert = alert,
 		.server = server,
 		.peer = peer,
 		.state = STATE_INIT,
diff --git a/src/libtls/tls_server.h b/src/libtls/tls_server.h
index 6dc26cd3f..6289dc8eb 100644
--- a/src/libtls/tls_server.h
+++ b/src/libtls/tls_server.h
@@ -41,8 +41,15 @@ struct tls_server_t {
 
 /**
  * Create a tls_server instance.
+ *
+ * @param tls		TLS stack
+ * @param crypto	TLS crypto helper
+ * @param alert		TLS alert handler
+ * @param server	server identity
+ * @param peer		peer identity
  */
-tls_server_t *tls_server_create(tls_t *tls, tls_crypto_t *crypto,
-							identification_t *server, identification_t *peer);
+tls_server_t *tls_server_create(tls_t *tls,
+						tls_crypto_t *crypto, tls_alert_t *alert,
+						identification_t *server, identification_t *peer);
 
 #endif /** TLS_SERVER_H_ @}*/