/* $OpenBSD: ec_pmeth.c,v 1.10 2017/01/29 17:49:23 beck Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include <string.h>

#include <openssl/asn1t.h>
#include <openssl/ec.h>
#include <openssl/ecdsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/x509.h>

#include "evp_locl.h"

/* EC pkey context structure */

typedef struct {
	/* Key and paramgen group */
	EC_GROUP *gen_group;
	/* message digest */
	const EVP_MD *md;
} EC_PKEY_CTX;

static int 
pkey_ec_init(EVP_PKEY_CTX * ctx)
{
	EC_PKEY_CTX *dctx;
	dctx = malloc(sizeof(EC_PKEY_CTX));
	if (!dctx)
		return 0;
	dctx->gen_group = NULL;
	dctx->md = NULL;

	ctx->data = dctx;

	return 1;
}

static int 
pkey_ec_copy(EVP_PKEY_CTX * dst, EVP_PKEY_CTX * src)
{
	EC_PKEY_CTX *dctx, *sctx;
	if (!pkey_ec_init(dst))
		return 0;
	sctx = src->data;
	dctx = dst->data;
	if (sctx->gen_group) {
		dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
		if (!dctx->gen_group)
			return 0;
	}
	dctx->md = sctx->md;
	return 1;
}

static void 
pkey_ec_cleanup(EVP_PKEY_CTX * ctx)
{
	EC_PKEY_CTX *dctx = ctx->data;
	if (dctx) {
		EC_GROUP_free(dctx->gen_group);
		free(dctx);
	}
}

static int 
pkey_ec_sign(EVP_PKEY_CTX * ctx, unsigned char *sig, size_t * siglen,
    const unsigned char *tbs, size_t tbslen)
{
	int ret, type;
	unsigned int sltmp;
	EC_PKEY_CTX *dctx = ctx->data;
	EC_KEY *ec = ctx->pkey->pkey.ec;

	if (!sig) {
		*siglen = ECDSA_size(ec);
		return 1;
	} else if (*siglen < (size_t) ECDSA_size(ec)) {
		ECerror(EC_R_BUFFER_TOO_SMALL);
		return 0;
	}
	if (dctx->md)
		type = EVP_MD_type(dctx->md);
	else
		type = NID_sha1;


	ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);

	if (ret <= 0)
		return ret;
	*siglen = (size_t) sltmp;
	return 1;
}

static int 
pkey_ec_verify(EVP_PKEY_CTX * ctx,
    const unsigned char *sig, size_t siglen,
    const unsigned char *tbs, size_t tbslen)
{
	int ret, type;
	EC_PKEY_CTX *dctx = ctx->data;
	EC_KEY *ec = ctx->pkey->pkey.ec;

	if (dctx->md)
		type = EVP_MD_type(dctx->md);
	else
		type = NID_sha1;

	ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);

	return ret;
}

static int 
pkey_ec_derive(EVP_PKEY_CTX * ctx, unsigned char *key, size_t * keylen)
{
	int ret;
	size_t outlen;
	const EC_POINT *pubkey = NULL;
	if (!ctx->pkey || !ctx->peerkey) {
		ECerror(EC_R_KEYS_NOT_SET);
		return 0;
	}
	if (!key) {
		const EC_GROUP *group;
		group = EC_KEY_get0_group(ctx->pkey->pkey.ec);
		*keylen = (EC_GROUP_get_degree(group) + 7) / 8;
		return 1;
	}
	pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);

	/*
	 * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is
	 * not an error, the result is truncated.
	 */

	outlen = *keylen;

	ret = ECDH_compute_key(key, outlen, pubkey, ctx->pkey->pkey.ec, 0);
	if (ret < 0)
		return ret;
	*keylen = ret;
	return 1;
}

static int 
pkey_ec_ctrl(EVP_PKEY_CTX * ctx, int type, int p1, void *p2)
{
	EC_PKEY_CTX *dctx = ctx->data;
	EC_GROUP *group;
	switch (type) {
	case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
		group = EC_GROUP_new_by_curve_name(p1);
		if (group == NULL) {
			ECerror(EC_R_INVALID_CURVE);
			return 0;
		}
		EC_GROUP_free(dctx->gen_group);
		dctx->gen_group = group;
		return 1;

	case EVP_PKEY_CTRL_MD:
		if (EVP_MD_type((const EVP_MD *) p2) != NID_sha1 &&
		    EVP_MD_type((const EVP_MD *) p2) != NID_ecdsa_with_SHA1 &&
		    EVP_MD_type((const EVP_MD *) p2) != NID_sha224 &&
		    EVP_MD_type((const EVP_MD *) p2) != NID_sha256 &&
		    EVP_MD_type((const EVP_MD *) p2) != NID_sha384 &&
		    EVP_MD_type((const EVP_MD *) p2) != NID_sha512) {
			ECerror(EC_R_INVALID_DIGEST_TYPE);
			return 0;
		}
		dctx->md = p2;
		return 1;

	case EVP_PKEY_CTRL_PEER_KEY:
		/* Default behaviour is OK */
	case EVP_PKEY_CTRL_DIGESTINIT:
	case EVP_PKEY_CTRL_PKCS7_SIGN:
	case EVP_PKEY_CTRL_CMS_SIGN:
		return 1;

	default:
		return -2;

	}
}

static int 
pkey_ec_ctrl_str(EVP_PKEY_CTX * ctx,
    const char *type, const char *value)
{
	if (!strcmp(type, "ec_paramgen_curve")) {
		int nid;
		nid = EC_curve_nist2nid(value);
		if (nid == NID_undef)
			nid = OBJ_sn2nid(value);
		if (nid == NID_undef)
			nid = OBJ_ln2nid(value);
		if (nid == NID_undef) {
			ECerror(EC_R_INVALID_CURVE);
			return 0;
		}
		return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
	}
	return -2;
}

static int 
pkey_ec_paramgen(EVP_PKEY_CTX * ctx, EVP_PKEY * pkey)
{
	EC_KEY *ec = NULL;
	EC_PKEY_CTX *dctx = ctx->data;
	int ret = 0;
	if (dctx->gen_group == NULL) {
		ECerror(EC_R_NO_PARAMETERS_SET);
		return 0;
	}
	ec = EC_KEY_new();
	if (!ec)
		return 0;
	ret = EC_KEY_set_group(ec, dctx->gen_group);
	if (ret)
		EVP_PKEY_assign_EC_KEY(pkey, ec);
	else
		EC_KEY_free(ec);
	return ret;
}

static int 
pkey_ec_keygen(EVP_PKEY_CTX * ctx, EVP_PKEY * pkey)
{
	EC_KEY *ec = NULL;
	if (ctx->pkey == NULL) {
		ECerror(EC_R_NO_PARAMETERS_SET);
		return 0;
	}
	ec = EC_KEY_new();
	if (!ec)
		return 0;
	EVP_PKEY_assign_EC_KEY(pkey, ec);
	/* Note: if error return, pkey is freed by parent routine */
	if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
		return 0;
	return EC_KEY_generate_key(pkey->pkey.ec);
}

const EVP_PKEY_METHOD ec_pkey_meth = {
	.pkey_id = EVP_PKEY_EC,

	.init = pkey_ec_init,
	.copy = pkey_ec_copy,
	.cleanup = pkey_ec_cleanup,

	.paramgen = pkey_ec_paramgen,

	.keygen = pkey_ec_keygen,

	.sign = pkey_ec_sign,

	.verify = pkey_ec_verify,

	.derive = pkey_ec_derive,

	.ctrl = pkey_ec_ctrl,
	.ctrl_str = pkey_ec_ctrl_str
};