1 files changed, 442 insertions, 0 deletions
diff --git a/src/libcharon/plugins/eap_tls/eap_tls.c b/src/libcharon/plugins/eap_tls/eap_tls.c
new file mode 100644
index 000000000..cf4294970
--- /dev/null
+++ b/src/libcharon/plugins/eap_tls/eap_tls.c
@@ -0,0 +1,442 @@
+/*
+ * 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 "eap_tls.h"
+
+#include "tls/tls.h"
+
+#include <daemon.h>
+#include <library.h>
+
+typedef struct private_eap_tls_t private_eap_tls_t;
+
+/**
+ * Private data of an eap_tls_t object.
+ */
+struct private_eap_tls_t {
+
+	/**
+	 * Public interface.
+	 */
+	eap_tls_t public;
+
+	/**
+	 * Number of EAP-TLS messages processed so far
+	 */
+	int processed;
+
+	/**
+	 * Is this method instance acting as server?
+	 */
+	bool is_server;
+
+	/**
+	 * TLS layers
+	 */
+	tls_t *tls;
+
+	/**
+	 * Allocated input buffer
+	 */
+	chunk_t input;
+
+	/**
+	 * Number of bytes read in input buffer
+	 */
+	size_t inpos;
+
+	/**
+	 * Allocated ouput buffer
+	 */
+	chunk_t output;
+
+	/**
+	 * Number of bytes sent from output buffer
+	 */
+	size_t outpos;
+};
+
+/** Size limit for a single TLS message */
+#define MAX_TLS_MESSAGE_LEN 16384
+/** Size of a EAP-TLS fragment */
+#define EAP_TLS_FRAGMENT_LEN 1014
+/** Maximum number of EAP-TLS messages/fragments allowed */
+#define MAX_EAP_TLS_MESSAGE_COUNT 16
+
+/**
+ * Flags of an EAP-TLS message
+ */
+typedef enum {
+	EAP_TLS_LENGTH = (1<<7),
+	EAP_TLS_MORE_FRAGS = (1<<6),
+	EAP_TLS_START = (1<<5),
+} eap_tls_flags_t;
+
+/**
+ * EAP-TLS packet format
+ */
+typedef struct __attribute__((packed)) {
+	u_int8_t code;
+	u_int8_t identifier;
+	u_int16_t length;
+	u_int8_t type;
+	u_int8_t flags;
+} eap_tls_packet_t;
+
+/**
+ * TLS record
+ */
+typedef struct __attribute__((packed)) {
+	u_int8_t type;
+	u_int16_t version;
+	u_int16_t length;
+	char data[];
+} tls_record_t;
+
+METHOD(eap_method_t, initiate, status_t,
+	private_eap_tls_t *this, eap_payload_t **out)
+{
+	if (this->is_server)
+	{
+		eap_tls_packet_t pkt = {
+			.type = EAP_TLS,
+			.code = EAP_REQUEST,
+			.flags = EAP_TLS_START,
+		};
+		htoun16(&pkt.length, sizeof(eap_tls_packet_t));
+		/* start with non-zero random identifier */
+		do {
+			pkt.identifier = random();
+		} while (!pkt.identifier);
+
+		*out = eap_payload_create_data(chunk_from_thing(pkt));
+		return NEED_MORE;
+	}
+	return FAILED;
+}
+
+/**
+ * Write received TLS data to the input buffer
+ */
+static bool write_buf(private_eap_tls_t *this, eap_tls_packet_t *pkt)
+{
+	u_int32_t msg_len;
+	u_int16_t pkt_len;
+	chunk_t data;
+
+	pkt_len = untoh16(&pkt->length);
+
+	if (pkt->flags & EAP_TLS_LENGTH)
+	{
+		if (pkt_len < sizeof(eap_tls_packet_t) + sizeof(msg_len))
+		{
+			DBG1(DBG_IKE, "EAP-TLS packet too short");
+			return FALSE;
+		}
+		msg_len = untoh32(pkt + 1);
+		if (msg_len < pkt_len - sizeof(eap_tls_packet_t) - sizeof(msg_len) ||
+			msg_len > MAX_TLS_MESSAGE_LEN)
+		{
+			DBG1(DBG_IKE, "invalid EAP-TLS packet length");
+			return FALSE;
+		}
+		if (this->input.ptr)
+		{
+			if (msg_len != this->input.len)
+			{
+				DBG1(DBG_IKE, "received unexpected TLS message length");
+				return FALSE;
+			}
+		}
+		else
+		{
+			this->input = chunk_alloc(msg_len);
+			this->inpos = 0;
+		}
+		data = chunk_create((char*)(pkt + 1) + sizeof(msg_len),
+						pkt_len - sizeof(eap_tls_packet_t) - sizeof(msg_len));
+	}
+	else
+	{
+		data = chunk_create((char*)(pkt + 1),
+						pkt_len - sizeof(eap_tls_packet_t));
+	}
+	if (data.len > this->input.len - this->inpos)
+	{
+		DBG1(DBG_IKE, "EAP-TLS fragment exceeds TLS message length");
+		return FALSE;
+	}
+	memcpy(this->input.ptr + this->inpos, data.ptr, data.len);
+	this->inpos += data.len;
+	return TRUE;
+}
+
+/**
+ * Send an ack to request next fragment
+ */
+static eap_payload_t *create_ack(private_eap_tls_t *this, u_int8_t identifier)
+{
+	eap_tls_packet_t pkt = {
+		.code = this->is_server ? EAP_REQUEST : EAP_RESPONSE,
+		.identifier = this->is_server ? identifier + 1 : identifier,
+		.type = EAP_TLS,
+	};
+	htoun16(&pkt.length, sizeof(pkt));
+
+	return eap_payload_create_data(chunk_from_thing(pkt));
+}
+
+/**
+ * Create a eap response from data in the TLS output buffer
+ */
+static eap_payload_t *read_buf(private_eap_tls_t *this, u_int8_t identifier)
+{
+	char buf[EAP_TLS_FRAGMENT_LEN + sizeof(eap_tls_packet_t) + 4], *start;
+	eap_tls_packet_t *pkt = (eap_tls_packet_t*)buf;
+	u_int16_t pkt_len = sizeof(eap_tls_packet_t);
+
+	pkt->code = this->is_server ? EAP_REQUEST : EAP_RESPONSE;
+	pkt->identifier = this->is_server ? identifier + 1 : identifier;
+	pkt->type = EAP_TLS;
+	pkt->flags = 0;
+
+	if (this->output.len)
+	{
+		start = (char*)(pkt + 1);
+		if (this->outpos == 0)
+		{	/* first fragment */
+			pkt->flags = EAP_TLS_LENGTH;
+			pkt_len += 4;
+			start += 4;
+			htoun32(pkt + 1, this->output.len);
+		}
+
+		if (this->output.len - this->outpos > EAP_TLS_FRAGMENT_LEN)
+		{
+			pkt->flags |= EAP_TLS_MORE_FRAGS;
+			pkt_len += EAP_TLS_FRAGMENT_LEN;
+			memcpy(start, this->output.ptr + this->outpos, EAP_TLS_FRAGMENT_LEN);
+			this->outpos += EAP_TLS_FRAGMENT_LEN;
+		}
+		else
+		{
+			pkt_len += this->output.len - this->outpos;
+			memcpy(start, this->output.ptr + this->outpos,
+				   this->output.len - this->outpos);
+			chunk_free(&this->output);
+			this->outpos = 0;
+		}
+	}
+	htoun16(&pkt->length, pkt_len);
+	return eap_payload_create_data(chunk_create(buf, pkt_len));
+}
+
+/**
+ * Pass data in input buffer to upper layers, write result to output buffer
+ */
+static status_t process_buf(private_eap_tls_t *this)
+{
+	tls_record_t *in, out;
+	chunk_t data;
+	u_int16_t len;
+	status_t status;
+
+	/* pass input buffer to upper layer, record for record */
+	data = this->input;
+	while (data.len > sizeof(tls_record_t))
+	{
+		in = (tls_record_t*)data.ptr;
+		len = untoh16(&in->length);
+		if (len > data.len - sizeof(tls_record_t))
+		{
+			DBG1(DBG_IKE, "TLS record length invalid");
+			return FAILED;
+		}
+		if (untoh16(&in->version) < TLS_1_0)
+		{
+			DBG1(DBG_IKE, "%N invalid with EAP-TLS",
+				 tls_version_names, untoh16(&in->version));
+			return FAILED;
+		}
+
+		status = this->tls->process(this->tls, in->type,
+									chunk_create(in->data, len));
+		if (status != NEED_MORE)
+		{
+			return status;
+		}
+		data = chunk_skip(data, len + sizeof(tls_record_t));
+	}
+	chunk_free(&this->input);
+	this->inpos = 0;
+
+	/* read in records from upper layer, append to output buffer */
+	chunk_free(&this->output);
+	while (TRUE)
+	{
+		tls_content_type_t type;
+		chunk_t header = chunk_from_thing(out);
+
+		status = this->tls->build(this->tls, &type, &data);
+		switch (status)
+		{
+			case NEED_MORE:
+				break;
+			case INVALID_STATE:
+				/* invalid state means we need more input from peer first */
+				return NEED_MORE;
+			case SUCCESS:
+				return SUCCESS;
+			case FAILED:
+			default:
+				return FAILED;
+		}
+		out.type = type;
+		htoun16(&out.version, this->tls->get_version(this->tls));
+		htoun16(&out.length, data.len);
+		this->output = chunk_cat("mcm", this->output, header, data);
+	}
+}
+
+METHOD(eap_method_t, process, status_t,
+	private_eap_tls_t *this, eap_payload_t *in, eap_payload_t **out)
+{
+	eap_tls_packet_t *pkt;
+	chunk_t data;
+	status_t status;
+
+	if (++this->processed > MAX_EAP_TLS_MESSAGE_COUNT)
+	{
+		DBG1(DBG_IKE, "EAP-TLS packet count exceeded");
+		return FAILED;
+	}
+
+	data = in->get_data(in);
+
+	pkt = (eap_tls_packet_t*)data.ptr;
+	if (data.len < sizeof(eap_tls_packet_t) ||
+		untoh16(&pkt->length) != data.len)
+	{
+		DBG1(DBG_IKE, "invalid EAP-TLS packet length");
+		return FAILED;
+	}
+	if (!(pkt->flags & EAP_TLS_START))
+	{
+		if (data.len == sizeof(eap_tls_packet_t))
+		{
+			if (this->output.len)
+			{	/* ACK to our fragment, send next */
+				*out = read_buf(this, pkt->identifier);
+				return NEED_MORE;
+			}
+			if (this->tls->is_complete(this->tls))
+			{
+				return SUCCESS;
+			}
+			return FAILED;
+		}
+		if (!write_buf(this, pkt))
+		{
+			return FAILED;
+		}
+		if (pkt->flags & EAP_TLS_MORE_FRAGS)
+		{	/* more fragments follow */
+			*out = create_ack(this, pkt->identifier);
+			return NEED_MORE;
+		}
+		else if (this->input.len != this->inpos)
+		{
+			DBG1(DBG_IKE, "defragemented TLS message has invalid length");
+			return FAILED;
+		}
+	}
+	status = process_buf(this);
+	if (status == NEED_MORE)
+	{
+		*out = read_buf(this, pkt->identifier);
+	}
+	return status;
+}
+
+METHOD(eap_method_t, get_type, eap_type_t,
+	private_eap_tls_t *this, u_int32_t *vendor)
+{
+	*vendor = 0;
+	return EAP_TLS;
+}
+
+METHOD(eap_method_t, get_msk, status_t,
+	private_eap_tls_t *this, chunk_t *msk)
+{
+	*msk = this->tls->get_eap_msk(this->tls);
+	if (msk->len)
+	{
+		return SUCCESS;
+	}
+	return FAILED;
+}
+
+METHOD(eap_method_t, is_mutual, bool,
+	private_eap_tls_t *this)
+{
+	return TRUE;
+}
+
+METHOD(eap_method_t, destroy, void,
+	private_eap_tls_t *this)
+{
+	free(this->input.ptr);
+	free(this->output.ptr);
+
+	this->tls->destroy(this->tls);
+
+	free(this);
+}
+
+/**
+ * Generic private constructor
+ */
+static eap_tls_t *eap_tls_create(identification_t *server,
+								 identification_t *peer, bool is_server)
+{
+	private_eap_tls_t *this;
+
+	INIT(this,
+		.public.eap_method = {
+			.initiate = _initiate,
+			.process = _process,
+			.get_type = _get_type,
+			.is_mutual = _is_mutual,
+			.get_msk = _get_msk,
+			.destroy = _destroy,
+		},
+		.is_server = is_server,
+	);
+	this->tls = tls_create(is_server, server, peer);
+
+	return &this->public;
+}
+
+eap_tls_t *eap_tls_create_server(identification_t *server,
+								 identification_t *peer)
+{
+	return eap_tls_create(server, peer, TRUE);
+}
+
+eap_tls_t *eap_tls_create_peer(identification_t *server,
+							   identification_t *peer)
+{
+	return eap_tls_create(server, peer, FALSE);
+}