/*
 *   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.
 *
 *   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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
#ifndef FR_TLS_H
#define FR_TLS_H

#ifdef WITH_TLS
/**
 * $Id: 520553bec3a2d25155216a10d3d4afd8b8ca2ab4 $
 *
 * @file tls.h
 * @brief Structures and prototypes for TLS wrappers
 *
 * @copyright 2010 Network RADIUS SARL <info@networkradius.com>
 */

RCSIDH(tls_h, "$Id: 520553bec3a2d25155216a10d3d4afd8b8ca2ab4 $")

#include <freeradius/conffile.h>

/*
 *	For RH 9, which apparently needs this.
 */
#ifndef OPENSSL_NO_KRB5
#  define OPENSSL_NO_KRB5
#endif
#include <openssl/err.h>
#if 1
#  include <openssl/engine.h>
#endif
#include <openssl/ssl.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef struct fr_tls_server_conf_t fr_tls_server_conf_t;

typedef enum {
	FR_TLS_INVALID = 0,	  		//!< Invalid, don't reply.
	FR_TLS_REQUEST,       			//!< Request, ok to send, invalid to receive.
	FR_TLS_RESPONSE,       			//!< Response, ok to receive, invalid to send.
	FR_TLS_SUCCESS,       			//!< Success, send success.
	FR_TLS_FAIL,       			//!< Fail, send fail.
	FR_TLS_NOOP,       			//!< Noop, continue.

	FR_TLS_START,       			//!< Start, ok to send, invalid to receive.
	FR_TLS_OK, 		 		//!< Ok, continue.
	FR_TLS_ACK,       			//!< Acknowledge, continue.
	FR_TLS_FIRST_FRAGMENT,    		//!< First fragment.
	FR_TLS_MORE_FRAGMENTS,    		//!< More fragments, to send/receive.
	FR_TLS_LENGTH_INCLUDED,	  		//!< Length included.
	FR_TLS_MORE_FRAGMENTS_WITH_LENGTH,   	//!< More fragments with length.
	FR_TLS_HANDLED	  			//!< TLS code has handled it.
} fr_tls_status_t;
extern FR_NAME_NUMBER const fr_tls_status_table[];

#define MAX_RECORD_SIZE 16384

/*
 *	A single TLS record may be up to 16384 octets in length, but a
 *	TLS message may span multiple TLS records, and a TLS
 *	certificate message may in principle be as long as 16MB.
 *
 *	However, note that in order to protect against reassembly
 *	lockup and denial of service attacks, it may be desirable for
 *	an implementation to set a maximum size for one such group of
 *	TLS messages.
 *
 *	The TLS Message Length field is four octets, and provides the
 *	total length of the TLS message or set of messages that is
 *	being fragmented; this simplifies buffer allocation.
 */

/*
 * FIXME: Dynamic allocation of buffer to overcome MAX_RECORD_SIZE overflows.
 * 	or configure TLS not to exceed MAX_RECORD_SIZE.
 */
typedef struct _record_t {
	uint8_t data[MAX_RECORD_SIZE];
	size_t  used;
} record_t;

typedef struct _tls_info_t {
	int		origin;
	int		content_type;
	uint8_t		handshake_type;
	uint8_t		alert_level;
	uint8_t		alert_description;
	bool		initialized;

	char 		info_description[256];
	size_t		record_len;
	int		version;
} tls_info_t;

#if OPENSSL_VERSION_NUMBER < 0x10001000L
#define ssl_session ssl->session
#else
#define ssl_session session
#endif

/** Contains EAP-REQUEST specific data (ie FR_TLS_DATA(fragment), EAPTLS-ALERT, EAPTLS-REQUEST ...)
 *
 * The tls_session_t Structure gets stored as opaque in eap_handler_t
 */
typedef struct _tls_session_t {
	SSL_CTX		*ctx;
	SSL 		*ssl;
#if OPENSSL_VERSION_NUMBER >= 0x10001000L
	SSL_SESSION	*session;
#endif
	tls_info_t	info;

	BIO 		*into_ssl;
	BIO 		*from_ssl;
	record_t 	clean_in;			//!< Data that needs to be sent but only after it is soiled.
	record_t 	clean_out;			//!< Data that is cleaned after receiving.
	record_t 	dirty_in;			//!< Data EAP server receives.
	record_t 	dirty_out;			//!< Data EAP server sends.

	void 		(*record_init)(record_t *buf);
	void 		(*record_close)(record_t *buf);
	unsigned int 	(*record_plus)(record_t *buf, void const *ptr, unsigned int size);
	unsigned int 	(*record_minus)(record_t *buf, void *ptr, unsigned int size);

	bool		invalid_hb_used;		//!< Whether heartbleed attack was detected.

	/*
	 *	Framed-MTU attribute in RADIUS, if present, can also be used to set this
	 */
	size_t 		mtu;				//!< Current fragment size transmitted.
	size_t		tls_msg_len;			//!< Actual/Total TLS message length.
	bool		fragment;			//!< Flag, In fragment mode or not.
	bool		length_flag;			//!< A flag to include length in every TLS Data/Alert packet.
							//!< If set to no then only the first fragment contains length.
	int		peap_flag;

	size_t		tls_record_in_total_len;	//!< How long the peer indicated the complete tls record
							//!< would be.
	size_t		tls_record_in_recvd_len;	//!< How much of the record we've received so far.

	/*
	 *	Used by TTLS & PEAP to keep track of other per-session data.
	 */
	void 		*opaque;
	void 		(*free_opaque)(void *opaque);

	char const	*prf_label;
	bool		allow_session_resumption;	//!< Whether session resumption is allowed.
} tls_session_t;

/*
 *	RFC 2716, Section 4.2:
 *
 *	   Flags
 *
 *      0 1 2 3 4 5 6 7 8
 *      +-+-+-+-+-+-+-+-+
 *      |L M S R R R R R|
 *      +-+-+-+-+-+-+-+-+
 *
 *      L = Length included
 *      M = More fragments
 *      S = EAP-TLS start
 *      R = Reserved
 */
#define TLS_START(x) 		(((x) & 0x20) != 0)
#define TLS_MORE_FRAGMENTS(x) 	(((x) & 0x40) != 0)
#define TLS_LENGTH_INCLUDED(x) 	(((x) & 0x80) != 0)

#define TLS_CHANGE_CIPHER_SPEC(x) 	(((x) & 0x0014) == 0x0014)
#define TLS_ALERT(x) 			(((x) & 0x0015) == 0x0015)
#define TLS_HANDSHAKE(x) 		(((x) & 0x0016) == 0x0016)

#define SET_START(x) 		((x) | (0x20))
#define SET_MORE_FRAGMENTS(x) 	((x) | (0x40))
#define SET_LENGTH_INCLUDED(x) 	((x) | (0x80))

/*
 *	Following enums from rfc2246
 *
 *	Hmm... since we dpeend on OpenSSL, it would be smarter to
 *	use the OpenSSL names for these.
 */
enum ContentType {
	change_cipher_spec = 20,
	alert = 21,
	handshake = 22,
	application_data = 23
};

enum AlertLevel {
	warning = 1,
	fatal = 2
};

enum AlertDescription {
	close_notify = 0,
	unexpected_message = 10,
	bad_record_mac = 20,
	decryption_failed = 21,
	record_overflow = 22,
	decompression_failure = 30,
	handshake_failure = 40,
	bad_certificate = 42,
	unsupported_certificate = 43,
	certificate_revoked = 44,
	certificate_expired = 45,
	certificate_unknown = 46,
	illegal_parameter = 47,
	unknown_ca = 48,
	access_denied = 49,
	decode_error = 50,
	decrypt_error = 51,
	export_restriction = 60,
	protocol_version = 70,
	insufficient_security = 71,
	internal_error = 80,
	user_canceled = 90,
	no_renegotiation = 100
};

enum HandshakeType {
	hello_request = 0,
	client_hello = 1,
	server_hello = 2,
	certificate = 11,
	server_key_exchange  = 12,
	certificate_request = 13,
	server_hello_done = 14,
	certificate_verify = 15,
	client_key_exchange = 16,
	handshake_finished = 20
};


/*
 * From rfc
   Flags

      0 1 2 3 4 5 6 7 8
      +-+-+-+-+-+-+-+-+
      |L M S R R R R R|
      +-+-+-+-+-+-+-+-+

      L = Length included
      M = More fragments
      S = EAP-TLS start
      R = Reserved

      The L bit (length included) is set to indicate the presence of the
      four octet TLS Message Length field, and MUST be set for the first
      fragment of a fragmented TLS message or set of messages. The M bit
      (more fragments) is set on all but the last fragment. The S bit
      (EAP-TLS start) is set in an EAP-TLS Start message.  This
      differentiates the EAP-TLS Start message from a fragment
      acknowledgement.

   TLS Message Length

      The TLS Message Length field is four octets, and is present only
      if the L bit is set. This field provides the total length of the
      TLS message or set of messages that is being fragmented.

   TLS data

      The TLS data consists of the encapsulated TLS packet in TLS record
      format.
 *
 * The data structures present here
 * maps only to the typedata in the EAP packet
 *
 * Based on the L bit flag, first 4 bytes of data indicate the length
 */

/* Callbacks */
int 		cbtls_password(char *buf, int num, int rwflag, void *userdata);
void 		cbtls_info(SSL const *s, int where, int ret);
void 		cbtls_msg(int write_p, int msg_version, int content_type, void const *buf, size_t len, SSL *ssl,
			  void *arg);
int		cbtls_verify(int ok, X509_STORE_CTX *ctx);

/* TLS */
void		tls_global_init(void);
#if 1
int		tls_global_version_check(char const *acknowledged);
#endif

int		tls_error_log(REQUEST *request, char const *msg, ...) CC_HINT(format (printf, 2, 3));
int		tls_error_io_log(REQUEST *request, tls_session_t *session, int ret, char const *msg, ...)
				 CC_HINT(format (printf, 4, 5));

void		tls_global_cleanup(void);
tls_session_t	*tls_new_session(TALLOC_CTX *ctx, fr_tls_server_conf_t *conf, REQUEST *request, bool client_cert);
tls_session_t	*tls_new_client_session(TALLOC_CTX *ctx, fr_tls_server_conf_t *conf, int fd);
fr_tls_server_conf_t *tls_server_conf_parse(CONF_SECTION *cs);
fr_tls_server_conf_t *tls_client_conf_parse(CONF_SECTION *cs);
SSL_CTX		*tls_init_ctx(fr_tls_server_conf_t *conf, int client);
int 		tls_handshake_recv(REQUEST *, tls_session_t *ssn);
int 		tls_handshake_send(REQUEST *, tls_session_t *ssn);
void 		tls_session_information(tls_session_t *ssn);
void		tls_session_id(SSL_SESSION *ssn, char *buffer, size_t bufsize);

/*
 *	Low-level TLS stuff
 */
int tls_success(tls_session_t *ssn, REQUEST *request);
void tls_fail(tls_session_t *ssn);
fr_tls_status_t tls_ack_handler(tls_session_t *tls_session, REQUEST *request);
fr_tls_status_t tls_application_data(tls_session_t *ssn, REQUEST *request);

#define FR_TLS_EX_INDEX_HANDLER  (10)
#define FR_TLS_EX_INDEX_CONF	 (11)
#define FR_TLS_EX_INDEX_REQUEST	 (12)
#define FR_TLS_EX_INDEX_IDENTITY (13)
#define FR_TLS_EX_INDEX_STORE	 (14)
#define FR_TLS_EX_INDEX_SSN	 (15)
#define FR_TLS_EX_INDEX_TALLOC	 (16)

extern int fr_tls_ex_index_certs;
extern int fr_tls_ex_index_vps;

/* configured values goes right here */
struct fr_tls_server_conf_t {
	SSL_CTX		*ctx;
	CONF_SECTION	*cs;

	char const	*private_key_password;
	char const	*private_key_file;
	char const	*certificate_file;
	char const	*random_file;
	char const	*ca_path;
	char const	*ca_file;
	char const	*dh_file;
	char const	*rsa_file;
	uint32_t	verify_depth;
	bool		file_type;
	bool		include_length;
	bool		auto_chain;
	bool		disable_single_dh_use;
	bool		disable_tlsv1;
	bool		disable_tlsv1_1;
	bool		disable_tlsv1_2;

	/*
	 *	Always < 4096 (due to radius limit), 0 by default = 1024
	 */
	uint32_t	fragment_size;
	bool		check_crl;
	bool		check_all_crl;
	bool		allow_expired_crl;
	char const	*check_cert_cn;
	char const	*cipher_list;
	bool		cipher_server_preference;
	char const	*check_cert_issuer;

	bool     	session_cache_enable;
	uint32_t     	session_timeout;
	uint32_t     	session_cache_size;
	char const	*session_id_name;
	char const	*session_cache_path;
	char		session_context_id[SSL_MAX_SSL_SESSION_ID_LENGTH];
	time_t		session_last_flushed;

	bool		verify_skip_if_ocsp_ok;
	char const	*verify_tmp_dir;
	char const	*verify_client_cert_cmd;
	bool		require_client_cert;

#if 1
	/*
	 * OCSP Configuration
	 */
	bool		ocsp_enable;
	bool		ocsp_override_url;
	char const	*ocsp_url;
	bool		ocsp_use_nonce;
	X509_STORE	*ocsp_store;
	uint32_t	ocsp_timeout;
	bool		ocsp_softfail;
#endif

#if OPENSSL_VERSION_NUMBER >= 0x0090800fL
#ifndef OPENSSL_NO_ECDH
	char const	*ecdh_curve;
#endif
#endif

#ifdef PSK_MAX_IDENTITY_LEN
	char const	*psk_identity;
	char const	*psk_password;
	char const	*psk_query;
#endif

};

#ifdef __cplusplus
}
#endif

#endif	/* WITH_TLS */
#endif /* FR_TLS_H */
