/*
 *  Copyright (C) 2001,2002,2003 Nikos Mavroyanopoulos
 *  Copyright (C) 2004 Free Software Foundation
 *
 *  This file is part of GNUTLS.
 *
 *  The GNUTLS library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public   
 *  License as published by the Free Software Foundation; either 
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 *
 */

/* Some of the stuff needed for Certificate authentication is contained
 * in this file.
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <auth_cert.h>
#include <gnutls_cert.h>
#include <libtasn1.h>
#include <gnutls_datum.h>
#include <gnutls_mpi.h>
#include <gnutls_global.h>
#include <gnutls_algorithms.h>
#include <gnutls_dh.h>
#include <gnutls_str.h>
#include <gnutls_state.h>
#include <gnutls_auth_int.h>
#include <gnutls_x509.h>
#include <gnutls_extra.h>
#include "x509/compat.h"
#include "x509/x509.h"
#include "x509/mpi.h"

void gnutls_certificate_free_crls(gnutls_certificate_credentials sc);

/**
  * gnutls_certificate_free_keys - Used to free all the keys from a gnutls_certificate_credentials structure
  * @sc: is an &gnutls_certificate_credentials structure.
  *
  * This function will delete all the keys and the certificates associated
  * with the given credentials. This function must not be called when a
  * TLS negotiation that uses the credentials is in progress.
  *
  **/
void gnutls_certificate_free_keys(gnutls_certificate_credentials sc)
{
	uint i, j;

	for (i = 0; i < sc->ncerts; i++) {
		for (j = 0; j < sc->cert_list_length[i]; j++) {
			_gnutls_gcert_deinit( &sc->cert_list[i][j]);
		}
		gnutls_free( sc->cert_list[i]);
	}

	gnutls_free(sc->cert_list_length);
	sc->cert_list_length = NULL;

	gnutls_free(sc->cert_list);
	sc->cert_list = NULL;

	for (i = 0; i < sc->ncerts; i++) {
		_gnutls_gkey_deinit( &sc->pkey[i]);
	}

	gnutls_free( sc->pkey);
	sc->pkey = NULL;
	
	sc->ncerts = 0;

}

/**
  * gnutls_certificate_free_cas - Used to free all the CAs from a gnutls_certificate_credentials structure
  * @sc: is an &gnutls_certificate_credentials structure.
  *
  * This function will delete all the CAs associated
  * with the given credentials. Servers that do not use
  * gnutls_certificate_verify_peers() may call this to
  * save some memory.
  *
  **/
void gnutls_certificate_free_cas(gnutls_certificate_credentials sc)
{
	uint j;

        for (j = 0; j < sc->x509_ncas; j++) {
		gnutls_x509_crt_deinit( sc->x509_ca_list[j]);
        }
        
        sc->x509_ncas = 0;

	gnutls_free( sc->x509_ca_list);
	sc->x509_ca_list = NULL;

}

/**
  * gnutls_certificate_free_ca_names - Used to free all the CA names from a gnutls_certificate_credentials structure
  * @sc: is an &gnutls_certificate_credentials structure.
  *
  * This function will delete all the CA name in the
  * given credentials. Clients may call this to save some memory
  * since in client side the CA names are not used.
  *
  * CA names are used by servers to advertize the CAs they
  * support to clients.
  *
  **/
void gnutls_certificate_free_ca_names(gnutls_certificate_credentials sc)
{
	_gnutls_free_datum( &sc->x509_rdn_sequence);
}

/*-
  * _gnutls_certificate_get_dh_params - Returns the DH parameters pointer
  * @sc: is an &gnutls_certificate_credentials structure.
  *
  * This function will return the dh parameters pointer. This will read the
  * credentials structure, and cache the output to the session, so later
  * calls would not examine the credentials (or call a callback).
  *
  -*/
gnutls_dh_params _gnutls_certificate_get_dh_params(const gnutls_certificate_credentials sc,
	gnutls_session session)
{
gnutls_params_st params;
int ret;

	if (session->internals.params.cert_dh_params) {
		return session->internals.params.cert_dh_params;
	}

	if (sc->dh_params) {
		session->internals.params.cert_dh_params = sc->dh_params;
	} else if (sc->params_func) {
		ret = sc->params_func( session, GNUTLS_PARAMS_DH, &params);
		if (ret == 0 && params.type == GNUTLS_PARAMS_DH) {
			session->internals.params.cert_dh_params = params.params.dh;
			session->internals.params.free_cert_dh_params = params.deinit;
		}
	}
	
	return session->internals.params.cert_dh_params;
}

/*-
  * _gnutls_certificate_get_rsa_params - Returns the RSA parameters pointer
  * @sc: is an &gnutls_certificate_credentials structure.
  *
  * This function will return the rsa parameters pointer.
  *
  -*/
gnutls_rsa_params _gnutls_certificate_get_rsa_params(const gnutls_certificate_credentials sc,
	gnutls_session session)
{
gnutls_params_st params;
int ret;

	if (session->internals.params.rsa_params) {
		return session->internals.params.rsa_params;
	}

	if (sc->rsa_params) {
		session->internals.params.rsa_params = sc->rsa_params;
	} else if (sc->params_func) {
		ret = sc->params_func( session, GNUTLS_PARAMS_RSA_EXPORT, &params);
		if (ret == 0 && params.type == GNUTLS_PARAMS_RSA_EXPORT) {
			session->internals.params.rsa_params = params.params.rsa_export;
			session->internals.params.free_rsa_params = params.deinit;
		}
	}
	
	return session->internals.params.rsa_params;
}


/**
  * gnutls_certificate_free_credentials - Used to free an allocated gnutls_certificate_credentials structure
  * @sc: is an &gnutls_certificate_credentials structure.
  *
  * This structure is complex enough to manipulate directly thus
  * this helper function is provided in order to free (deallocate) it.
  *
  * This function does not free any temporary parameters associated
  * with this structure (ie RSA and DH parameters are not freed by
  * this function).
  **/
void gnutls_certificate_free_credentials(gnutls_certificate_credentials sc)
{
	gnutls_certificate_free_keys( sc);
	gnutls_certificate_free_cas( sc);
#ifdef ENABLE_PKI
	gnutls_certificate_free_crls( sc);
#endif

	_gnutls_free_datum( &sc->keyring);

	gnutls_free( sc);
}


/**
  * gnutls_certificate_allocate_credentials - Used to allocate a gnutls_certificate_credentials structure
  * @res: is a pointer to an &gnutls_certificate_credentials structure.
  *
  * This structure is complex enough to manipulate directly thus
  * this helper function is provided in order to allocate it.
  *
  * Returns 0 on success.
  **/
int gnutls_certificate_allocate_credentials(gnutls_certificate_credentials * res)
{
	*res = gnutls_calloc(1, sizeof(CERTIFICATE_CREDENTIALS_INT));

	if (*res == NULL)
		return GNUTLS_E_MEMORY_ERROR;

	return 0;
}


/* returns the KX algorithms that are supported by a
 * certificate. (Eg a certificate with RSA params, supports
 * GNUTLS_KX_RSA algorithm).
 * This function also uses the KeyUsage field of the certificate
 * extensions in order to disable unneded algorithms.
 */
int _gnutls_selected_cert_supported_kx( gnutls_session session, gnutls_kx_algorithm ** alg,
			      int *alg_size)
{
	gnutls_kx_algorithm kx;
	gnutls_pk_algorithm pk;
	gnutls_kx_algorithm kxlist[MAX_ALGOS];
	gnutls_cert * cert;
	int i;
	
	if (session->internals.selected_cert_list_length == 0) {
		*alg_size = 0;
		*alg = NULL;
		return 0;
	}

	cert = &session->internals.selected_cert_list[0];
	i = 0;

	for (kx = 0; kx < MAX_ALGOS; kx++) {
		pk = _gnutls_map_pk_get_pk(kx);
		if (pk == cert->subject_pk_algorithm) {
			/* then check key usage */
			if (_gnutls_check_key_usage(cert, kx) == 0) {
				kxlist[i] = kx;
				i++;
			}
		}
	}

	if (i==0) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	*alg = gnutls_calloc(1, sizeof(gnutls_kx_algorithm) * i);
	if (*alg == NULL)
		return GNUTLS_E_MEMORY_ERROR;

	*alg_size = i;

	memcpy(*alg, kxlist, i * sizeof(gnutls_kx_algorithm));

	return 0;
}


/**
  * gnutls_certificate_server_set_request - Used to set whether to request a client certificate
  * @session: is an &gnutls_session structure.
  * @req: is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE
  *
  * This function specifies if we (in case of a server) are going
  * to send a certificate request message to the client. If @req
  * is GNUTLS_CERT_REQUIRE then the server will return an error if
  * the peer does not provide a certificate. If you do not
  * call this function then the client will not be asked to
  * send a certificate.
  **/
void gnutls_certificate_server_set_request(gnutls_session session,
					    gnutls_certificate_request req)
{
	session->internals.send_cert_req = req;
}

/**
  * gnutls_certificate_client_set_retrieve_function - Used to set a callback to retrieve the certificate
  * @cred: is a &gnutls_certificate_credentials structure.
  * @func: is the callback function
  *
  * This function sets a callback to be called in order to retrieve the certificate
  * to be used in the handshake.
  * The callback's function prototype is:
  * int (*callback)(gnutls_session, const gnutls_datum* req_ca_dn, int nreqs, 
  * gnutls_pk_algorithm* pk_algos, int pk_algos_length, gnutls_retr_st st);
  *
  * @st should contain the certificates and private keys.
  *
  * @req_ca_cert, is only used in X.509 certificates. 
  * Contains a list with the CA names that the server considers trusted. 
  * Normally we should send a certificate that is signed
  * by one of these CAs. These names are DER encoded. To get a more
  * meaningful value use the function gnutls_x509_rdn_get().
  *
  * @pk_algos, contains a list with server's acceptable signature algorithms.
  * The certificate returned should support the server's given algorithms.
  *
  * If the callback function is provided then gnutls will call it, in the
  * handshake, after the certificate request message has been received.
  *
  * The callback function should set the certificate list to be sent, and
  * return 0 on success. If no certificate was selected then the number of certificates
  * should be set to zero. The value (-1) indicates error and the handshake
  * will be terminated.
  **/
void gnutls_certificate_client_set_retrieve_function(gnutls_certificate_credentials cred,
			gnutls_certificate_client_retrieve_function * func)
{
	cred->client_get_cert_callback = func;
}

/**
  * gnutls_certificate_server_set_retrieve_function - Used to set a callback to retrieve the certificate
  * @cred: is a &gnutls_certificate_credentials structure.
  * @func: is the callback function
  *
  * This function sets a callback to be called in order to retrieve the certificate
  * to be used in the handshake.
  * The callback's function prototype is:
  * int (*callback)(gnutls_session, const gnutls_datum* req_ca_dn, int nreqs, 
  * gnutls_pk_algorithm* pk_algos, int pk_algos_length, gnutls_retr_st st);
  *
  * @st should contain the certificates and private keys.
  *
  * If the callback function is provided then gnutls will call it, in the
  * handshake, after the certificate request message has been received.
  *
  * The callback function should set the certificate list to be sent, and
  * return 0 on success.  The value (-1) indicates error and the handshake
  * will be terminated.
  **/
void gnutls_certificate_server_set_retrieve_function(gnutls_certificate_credentials cred,
			gnutls_certificate_server_retrieve_function * func)
{
	cred->server_get_cert_callback = func;
}


/* These are set by the gnutls_extra library's initialization function.
 */

OPENPGP_KEY_CREATION_TIME_FUNC _E_gnutls_openpgp_get_raw_key_creation_time = NULL;
OPENPGP_KEY_EXPIRATION_TIME_FUNC _E_gnutls_openpgp_get_raw_key_expiration_time = NULL;
OPENPGP_VERIFY_KEY_FUNC _E_gnutls_openpgp_verify_key = NULL;

/*-
  * _gnutls_openpgp_cert_verify_peers - This function returns the peer's certificate status
  * @session: is a gnutls session
  *
  * This function will try to verify the peer's certificate and return its status (TRUSTED, INVALID etc.). 
  * Returns a negative error code in case of an error, or GNUTLS_E_NO_CERTIFICATE_FOUND if no certificate was sent.
  *
  -*/
int _gnutls_openpgp_cert_verify_peers(gnutls_session session)
{
	CERTIFICATE_AUTH_INFO info;
	const gnutls_certificate_credentials cred;
	int verify;
	int peer_certificate_list_size;

	CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST);

	info = _gnutls_get_auth_info(session);
	if (info == NULL)
		return GNUTLS_E_INVALID_REQUEST;

	cred = _gnutls_get_cred(session->key, GNUTLS_CRD_CERTIFICATE, NULL);
	if (cred == NULL) {
		gnutls_assert();
		return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
	}

	if (info->raw_certificate_list == NULL || info->ncerts == 0) {
		gnutls_assert();
		return GNUTLS_E_NO_CERTIFICATE_FOUND;
	}
	
	/* generate a list of gnutls_certs based on the auth info
	 * raw certs.
	 */
	peer_certificate_list_size = info->ncerts;

	if (peer_certificate_list_size != 1) {
		gnutls_assert();
		return GNUTLS_E_INTERNAL_ERROR;
	}
	
	/* Verify certificate 
	 */
	if (_E_gnutls_openpgp_verify_key==NULL) {
		gnutls_assert();
		return GNUTLS_E_INIT_LIBEXTRA;
	}
	verify = _E_gnutls_openpgp_verify_key( cred->pgp_trustdb, &cred->keyring, &info->raw_certificate_list[0],
				      peer_certificate_list_size);

	if (verify < 0) {
		gnutls_assert();
	}

	return verify;
}

/**
  * gnutls_certificate_verify_peers - This function returns the peer's certificate verification status
  * @session: is a gnutls session
  *
  * This function will try to verify the peer's certificate and return its status (trusted, invalid etc.).
  * However you must also check the peer's name in order to check if the verified certificate belongs to the
  * actual peer.
  *
  * The return value should be one or more of the gnutls_certificate_status
  * enumerated elements bitwise or'd.
  *
  * This is the same as gnutls_x509_verify_certificate().
  *
  **/
int gnutls_certificate_verify_peers(gnutls_session session)
{
	CERTIFICATE_AUTH_INFO info;

	CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST);

	info = _gnutls_get_auth_info(session);
	if (info == NULL) {
		return GNUTLS_E_NO_CERTIFICATE_FOUND;
	}
	
	if (info->raw_certificate_list == NULL || info->ncerts == 0)
		return GNUTLS_E_NO_CERTIFICATE_FOUND;

	switch( gnutls_certificate_type_get( session)) {
		case GNUTLS_CRT_X509:
			return _gnutls_x509_cert_verify_peers( session);
		case GNUTLS_CRT_OPENPGP:
			return _gnutls_openpgp_cert_verify_peers( session);
		default:
			return GNUTLS_E_INVALID_REQUEST;
	}
}

/**
  * gnutls_certificate_expiration_time_peers - This function returns the peer's certificate expiration time
  * @session: is a gnutls session
  *
  * This function will return the peer's certificate expiration time.
  *
  * Returns (time_t) -1 on error.
  *
  **/
time_t gnutls_certificate_expiration_time_peers(gnutls_session session)
{
	CERTIFICATE_AUTH_INFO info;

	CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST);

	info = _gnutls_get_auth_info(session);
	if (info == NULL) {
		return (time_t) -1;
	}

	if (info->raw_certificate_list == NULL || info->ncerts == 0) {
		gnutls_assert();
		return (time_t) -1;
	}

	switch( gnutls_certificate_type_get( session)) {
		case GNUTLS_CRT_X509:
			return _gnutls_x509_get_raw_crt_expiration_time(
				&info->raw_certificate_list[0]);
		case GNUTLS_CRT_OPENPGP:
			if (_E_gnutls_openpgp_get_raw_key_expiration_time==NULL)
				return (time_t)-1;
			return _E_gnutls_openpgp_get_raw_key_expiration_time(
				&info->raw_certificate_list[0]);
		default:
			return (time_t)-1;
	}
}

/**
  * gnutls_certificate_activation_time_peers - This function returns the peer's certificate activation time
  * @session: is a gnutls session
  *
  * This function will return the peer's certificate activation time.
  * This is the creation time for openpgp keys.
  *
  * Returns (time_t) -1 on error.
  *
  **/
time_t gnutls_certificate_activation_time_peers(gnutls_session session)
{
	CERTIFICATE_AUTH_INFO info;

	CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST);

	info = _gnutls_get_auth_info(session);
	if (info == NULL) {
		return (time_t) -1;
	}
	
	if (info->raw_certificate_list == NULL || info->ncerts == 0) {
		gnutls_assert();
		return (time_t) -1;
	}

	switch( gnutls_certificate_type_get( session)) {
		case GNUTLS_CRT_X509:
			return _gnutls_x509_get_raw_crt_activation_time(
				&info->raw_certificate_list[0]);
		case GNUTLS_CRT_OPENPGP:
			if (_E_gnutls_openpgp_get_raw_key_creation_time==NULL)
				return (time_t)-1;
			return _E_gnutls_openpgp_get_raw_key_creation_time(
				&info->raw_certificate_list[0]);
		default:
			return (time_t)-1;
	}
}

OPENPGP_RAW_KEY_TO_GCERT _E_gnutls_openpgp_raw_key_to_gcert;
OPENPGP_RAW_PRIVKEY_TO_GKEY _E_gnutls_openpgp_raw_privkey_to_gkey;

int _gnutls_raw_cert_to_gcert(gnutls_cert * gcert, gnutls_certificate_type type,
	const gnutls_datum *raw_cert, int flags /* OR of ConvFlags */)
{
	switch( type) {
		case GNUTLS_CRT_X509:
			return _gnutls_x509_raw_cert_to_gcert( gcert,
					     raw_cert, flags);
		case GNUTLS_CRT_OPENPGP:
			if (_E_gnutls_openpgp_raw_key_to_gcert==NULL) {
				gnutls_assert();
				return GNUTLS_E_INIT_LIBEXTRA;
			}
			return
			     _E_gnutls_openpgp_raw_key_to_gcert( gcert,
					     raw_cert);
		default:
			gnutls_assert();
			return GNUTLS_E_INTERNAL_ERROR;
	}
}

int _gnutls_raw_privkey_to_gkey(gnutls_privkey * key, gnutls_certificate_type type,
	const gnutls_datum *raw_key, int key_enc /* DER or PEM */)
{
	switch( type) {
		case GNUTLS_CRT_X509:
			return _gnutls_x509_raw_privkey_to_gkey( key,
					     raw_key, key_enc);
		case GNUTLS_CRT_OPENPGP:
			if (_E_gnutls_openpgp_raw_privkey_to_gkey==NULL) {
				gnutls_assert();
				return GNUTLS_E_INIT_LIBEXTRA;
			}
			return
			     _E_gnutls_openpgp_raw_privkey_to_gkey( key, raw_key);
		default:
			gnutls_assert();
			return GNUTLS_E_INTERNAL_ERROR;
	}
}


/* This function will convert a der certificate to a format
 * (structure) that gnutls can understand and use. Actually the
 * important thing on this function is that it extracts the 
 * certificate's (public key) parameters.
 *
 * The noext flag is used to complete the handshake even if the
 * extensions found in the certificate are unsupported and critical. 
 * The critical extensions will be catched by the verification functions.
 */
int _gnutls_x509_raw_cert_to_gcert(gnutls_cert * gcert, const gnutls_datum *derCert,
	int flags /* OR of ConvFlags */)
{
	int ret;
	gnutls_x509_crt cert;
	
	ret = gnutls_x509_crt_init( &cert);
	if ( ret < 0) {
		gnutls_assert();
		return ret;
	}

	ret = gnutls_x509_crt_import( cert, derCert, GNUTLS_X509_FMT_DER);
	if ( ret < 0) {
		gnutls_assert();
		gnutls_x509_crt_deinit( cert);
		return ret;
	}
	
	ret = _gnutls_x509_crt_to_gcert( gcert, cert, flags);
	gnutls_x509_crt_deinit( cert);
	
	return ret;
}

/* Like above but it accepts a parsed certificate instead.
 */
int _gnutls_x509_crt_to_gcert(gnutls_cert * gcert, gnutls_x509_crt cert,
	unsigned int flags)
{
	int ret = 0;
	
	memset(gcert, 0, sizeof(gnutls_cert));
	gcert->cert_type = GNUTLS_CRT_X509;

	if ( !(flags & CERT_NO_COPY)) {
		#define SMALL_DER 512
		opaque* der;
		size_t der_size = SMALL_DER;

		/* initially allocate a bogus size, just in case the certificate
		 * fits in it. That way we minimize the DER encodings performed.
		 */
		der = gnutls_malloc( SMALL_DER);
		if (der == NULL) {
			gnutls_assert();
			return GNUTLS_E_MEMORY_ERROR;
		}
		
		ret = gnutls_x509_crt_export( cert, GNUTLS_X509_FMT_DER, der, &der_size);
		if (ret < 0 && ret != GNUTLS_E_SHORT_MEMORY_BUFFER) {
			gnutls_assert();
			gnutls_free(der);
			return ret;
		}
		
		if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER) {
			der = gnutls_realloc( der, der_size);
			if (der == NULL) {
				gnutls_assert();
				return GNUTLS_E_MEMORY_ERROR;
			}

			ret = gnutls_x509_crt_export( cert, GNUTLS_X509_FMT_DER, der, &der_size);
			if (ret < 0) {
				gnutls_assert();
				gnutls_free(der);
				return ret;
			}
		}

		gcert->raw.data = der;
		gcert->raw.size = der_size;
	} else
		/* now we have 0 or a bitwise or of things to decode */
		flags ^= CERT_NO_COPY;


	if (flags & CERT_ONLY_EXTENSIONS || flags == 0) {
		gnutls_x509_crt_get_key_usage( cert, &gcert->keyUsage, NULL);
		gcert->version = gnutls_x509_crt_get_version( cert);
	}
	gcert->subject_pk_algorithm = gnutls_x509_crt_get_pk_algorithm( cert, NULL);

	if (flags & CERT_ONLY_PUBKEY || flags == 0) {
		gcert->params_size = MAX_PUBLIC_PARAMS_SIZE;
		ret = _gnutls_x509_crt_get_mpis( cert, gcert->params, &gcert->params_size);
		if (ret < 0) {
			gnutls_assert();
			return ret;
		}
	}

	return 0;

}

void _gnutls_gcert_deinit(gnutls_cert *cert)
{
	int i;

	if (cert == NULL) return;

	for (i = 0; i < cert->params_size; i++) {
		_gnutls_mpi_release( &cert->params[i]);
	}

	_gnutls_free_datum(&cert->raw);
}