/*

 * Copyright (C) 2003-2012 Free Software Foundation, Inc.

 * Copyright (C) 2015-2017 Red Hat, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS.

 *

 * The GnuTLS 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 program.  If not, see <https://www.gnu.org/licenses/>

 *

 */

#include "gnutls_int.h"

#include "errors.h"

#include <global.h>

#include <libtasn1.h>

#include <datum.h>

#include "common.h"

#include "x509_int.h"

#include <num.h>

#include <limits.h>

/* Reads an Integer from the DER encoded data

 */

int _gnutls_x509_read_der_int(uint8_t * der, int dersize, bigint_t * out)

{

	int result;

	ASN1_TYPE spk = ASN1_TYPE_EMPTY;

	/* == INTEGER */

	if ((result = asn1_create_element

	     (_gnutls_get_gnutls_asn(), "GNUTLS.DSAPublicKey",

	      &spk)) != ASN1_SUCCESS) {

		gnutls_assert();

		return _gnutls_asn2err(result);

	}

	result = _asn1_strict_der_decode(&spk, der, dersize, NULL);

	if (result != ASN1_SUCCESS) {

		gnutls_assert();

		asn1_delete_structure(&spk;;

		return _gnutls_asn2err(result);

	}

	/* Read Y */

	if ((result = _gnutls_x509_read_int(spk, "", out)) < 0) {

		gnutls_assert();

		asn1_delete_structure(&spk;;

		return _gnutls_asn2err(result);

	}

	asn1_delete_structure(&spk;;

	return 0;

}

int _gnutls_x509_read_der_uint(uint8_t * der, int dersize, unsigned int *out)

{

	int result;

	ASN1_TYPE spk = ASN1_TYPE_EMPTY;

	/* == INTEGER */

	if ((result = asn1_create_element

	     (_gnutls_get_gnutls_asn(), "GNUTLS.DSAPublicKey",

	      &spk)) != ASN1_SUCCESS) {

		gnutls_assert();

		return _gnutls_asn2err(result);

	}

	result = _asn1_strict_der_decode(&spk, der, dersize, NULL);

	if (result != ASN1_SUCCESS) {

		gnutls_assert();

		asn1_delete_structure(&spk;;

		return _gnutls_asn2err(result);

	}

	/* Read Y */

	if ((result = _gnutls_x509_read_uint(spk, "", out)) < 0) {

		gnutls_assert();

		asn1_delete_structure(&spk;;

		return _gnutls_asn2err(result);

	}

	asn1_delete_structure(&spk;;

	return 0;

}

/* Extracts DSA and RSA parameters from a certificate.

 */

int

_gnutls_get_asn_mpis(ASN1_TYPE asn, const char *root,

		     gnutls_pk_params_st * params)

{

	int result;

	char name[256];

	gnutls_datum_t tmp = { NULL, 0 };

	gnutls_pk_algorithm_t pk_algorithm;

	gnutls_ecc_curve_t curve;

	gnutls_pk_params_init(params);

	result = _gnutls_x509_get_pk_algorithm(asn, root, &curve, NULL);

	if (result < 0) {

		gnutls_assert();

		return result;

	}

	pk_algorithm = result;

	params->curve = curve;

	params->algo = pk_algorithm;

	/* Read the algorithm's parameters

	 */

	_asnstr_append_name(name, sizeof(name), root,

			    ".algorithm.parameters");

	if (pk_algorithm != GNUTLS_PK_RSA &&

	    pk_algorithm != GNUTLS_PK_EDDSA_ED25519 && pk_algorithm != GNUTLS_PK_ECDH_X25519 &&

	    pk_algorithm != GNUTLS_PK_EDDSA_ED448 && pk_algorithm != GNUTLS_PK_ECDH_X448) {

		/* RSA and EdDSA do not use parameters */

		result = _gnutls_x509_read_value(asn, name, &tmp);

		if (pk_algorithm == GNUTLS_PK_RSA_PSS && 

		    (result == GNUTLS_E_ASN1_VALUE_NOT_FOUND || result == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND)) {

			goto skip_params;

		}

		if (result < 0) {

			gnutls_assert();

			goto error;

		}

		result =

		     _gnutls_x509_read_pubkey_params(pk_algorithm,

						     tmp.data, tmp.size,

						     params);

		if (result < 0) {

			gnutls_assert();

			goto error;

		}

		_gnutls_free_datum(&tmp);

	}

 skip_params:

	/* Now read the public key */

	_asnstr_append_name(name, sizeof(name), root, ".subjectPublicKey");

	result = _gnutls_x509_read_value(asn, name, &tmp);

	if (result < 0) {

		gnutls_assert();

		goto error;

	}

	if ((result =

	     _gnutls_x509_read_pubkey(pk_algorithm, tmp.data, tmp.size,

				      params)) < 0) {

		gnutls_assert();

		goto error;

	}

	result = _gnutls_x509_check_pubkey_params(params);

	if (result < 0) {

		gnutls_assert();

		goto error;

	}

	result = 0;

 error:

	if (result < 0)

		gnutls_pk_params_release(params);

	_gnutls_free_datum(&tmp);

	return result;

}

/* Extracts DSA and RSA parameters from a certificate.

 */

int

_gnutls_x509_crt_get_mpis(gnutls_x509_crt_t cert,

			  gnutls_pk_params_st * params)

{

	/* Read the algorithm's OID

	 */

	return _gnutls_get_asn_mpis(cert->cert,

				    "tbsCertificate.subjectPublicKeyInfo",

				    params);

}

/* Extracts DSA and RSA parameters from a certificate.

 */

int

_gnutls_x509_crq_get_mpis(gnutls_x509_crq_t cert,

			  gnutls_pk_params_st * params)

{

	/* Read the algorithm's OID

	 */

	return _gnutls_get_asn_mpis(cert->crq,

				    "certificationRequestInfo.subjectPKInfo",

				    params);

}

/*

 * This function reads and decodes the parameters for DSS or RSA keys.

 * This is the "signatureAlgorithm" fields.

 */

int

_gnutls_x509_read_pkalgo_params(ASN1_TYPE src, const char *src_name,

			      gnutls_x509_spki_st *spki, unsigned is_sig)

{

	int result;

	char name[128];

	char oid[MAX_OID_SIZE];

	int oid_size;

	memset(spki, 0, sizeof(*spki));

	_gnutls_str_cpy(name, sizeof(name), src_name);

	_gnutls_str_cat(name, sizeof(name), ".algorithm");

	oid_size = sizeof(oid);

	result = asn1_read_value(src, name, oid, &oid_size);

	if (result != ASN1_SUCCESS) {

		gnutls_assert();

		return _gnutls_asn2err(result);

	}

	if (strcmp (oid, PK_PKIX1_RSA_PSS_OID) == 0) {

		gnutls_datum_t tmp = { NULL, 0 };

		_gnutls_str_cpy(name, sizeof(name), src_name);

		_gnutls_str_cat(name, sizeof(name), ".parameters");

		result = _gnutls_x509_read_value(src, name, &tmp);

		if (result < 0) {

			if (!is_sig) {

				if (result == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND ||

				    result != GNUTLS_E_ASN1_VALUE_NOT_FOUND) {

					/* it is ok to not have parameters in SPKI, but

					 * not in signatures */

					return 0;

				}

			}

			return gnutls_assert_val(result);

		}

		result = _gnutls_x509_read_rsa_pss_params(tmp.data, tmp.size,

							  spki);

		_gnutls_free_datum(&tmp);

		if (result < 0)

			gnutls_assert();

		return result;

	}

	return 0;

}

static int write_oid_and_params(ASN1_TYPE dst, const char *dst_name, const char *oid, gnutls_x509_spki_st *params)

{

	int result;

	char name[128];

	if (params == NULL) {

		gnutls_assert();

		return GNUTLS_E_INVALID_REQUEST;

	}

	_gnutls_str_cpy(name, sizeof(name), dst_name);

	_gnutls_str_cat(name, sizeof(name), ".algorithm");

	/* write the OID.

	 */

	result = asn1_write_value(dst, name, oid, 1);

	if (result != ASN1_SUCCESS) {

		gnutls_assert();

		return _gnutls_asn2err(result);

	}

	_gnutls_str_cpy(name, sizeof(name), dst_name);

	_gnutls_str_cat(name, sizeof(name), ".parameters");

	if (params->pk == GNUTLS_PK_RSA)

		result =

		    asn1_write_value(dst, name, ASN1_NULL, ASN1_NULL_SIZE);

	else if (params->pk == GNUTLS_PK_RSA_PSS) {

		gnutls_datum_t tmp = { NULL, 0 };

		result = _gnutls_x509_write_rsa_pss_params(params, &tmp);

		if (result < 0)

			return gnutls_assert_val(result);

		result = asn1_write_value(dst, name, tmp.data, tmp.size);

		_gnutls_free_datum(&tmp);

	} else

		result = asn1_write_value(dst, name, NULL, 0);

	if (result != ASN1_SUCCESS && result != ASN1_ELEMENT_NOT_FOUND) {

		/* Here we ignore the element not found error, since this

		 * may have been disabled before.

		 */

		gnutls_assert();

		return _gnutls_asn2err(result);

	}

	return 0;

}

int

_gnutls_x509_write_spki_params(ASN1_TYPE dst, const char *dst_name,

			       gnutls_x509_spki_st *params)

{

	const char *oid;

	if (params->legacy && params->pk == GNUTLS_PK_RSA)

		oid = PK_PKIX1_RSA_OID;

	else if (params->pk == GNUTLS_PK_RSA_PSS)

		oid = PK_PKIX1_RSA_PSS_OID;

	else

		oid = gnutls_pk_get_oid(params->pk);

	if (oid == NULL) {

		gnutls_assert();

		_gnutls_debug_log

		    ("Cannot find OID for public key algorithm %s\n",

		     gnutls_pk_get_name(params->pk));

		return GNUTLS_E_INVALID_REQUEST;

	}

	return write_oid_and_params(dst, dst_name, oid, params);

}

int

_gnutls_x509_write_sign_params(ASN1_TYPE dst, const char *dst_name,

			       const gnutls_sign_entry_st *se, gnutls_x509_spki_st *params)

{

	const char *oid;

	if (params->legacy && params->pk == GNUTLS_PK_RSA)

		oid = PK_PKIX1_RSA_OID;

	else if (params->pk == GNUTLS_PK_RSA_PSS)

		oid = PK_PKIX1_RSA_PSS_OID;

	else

		oid = se->oid;

	if (oid == NULL) {

		gnutls_assert();

		_gnutls_debug_log

		    ("Cannot find OID for sign algorithm %s\n",

		     se->name);

		return GNUTLS_E_INVALID_REQUEST;

	}

	return write_oid_and_params(dst, dst_name, oid, params);

}

/* this function reads a (small) unsigned integer

 * from asn1 structs. Combines the read and the conversion

 * steps.

 */

int

_gnutls_x509_read_uint(ASN1_TYPE node, const char *value,

		       unsigned int *ret)

{

	int len, result;

	uint8_t *tmpstr;

	len = 0;

	result = asn1_read_value(node, value, NULL, &len;;

	if (result != ASN1_MEM_ERROR) {

		return _gnutls_asn2err(result);

	}

	tmpstr = gnutls_malloc(len);

	if (tmpstr == NULL) {

		gnutls_assert();

		return GNUTLS_E_MEMORY_ERROR;

	}

	result = asn1_read_value(node, value, tmpstr, &len;;

	if (result != ASN1_SUCCESS) {

		gnutls_assert();

		gnutls_free(tmpstr);

		return _gnutls_asn2err(result);

	}

	if (len == 1)

		*ret = tmpstr[0];

	else if (len == 2)

		*ret = _gnutls_read_uint16(tmpstr);

	else if (len == 3)

		*ret = _gnutls_read_uint24(tmpstr);

	else if (len == 4)

		*ret = _gnutls_read_uint32(tmpstr);

	else {

		gnutls_assert();

		gnutls_free(tmpstr);

		return GNUTLS_E_INTERNAL_ERROR;

	}

	gnutls_free(tmpstr);

	return 0;

}

/* Writes the specified integer into the specified node.

 */

int

_gnutls_x509_write_uint32(ASN1_TYPE node, const char *value, uint32_t num)

{

	uint8_t tmpstr[5];

	int result;

	tmpstr[0] = 0;

	_gnutls_write_uint32(num, tmpstr+1);

	if (tmpstr[1] > SCHAR_MAX) {

		result = asn1_write_value(node, value, tmpstr, 5);

	} else {

		result = asn1_write_value(node, value, tmpstr+1, 4);

	}

	if (result != ASN1_SUCCESS) {

		gnutls_assert();

		return _gnutls_asn2err(result);

	}

	return 0;

}