/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mpi.h"
#include "mplogic.h"
#include "ecl.h"
#include "ecl-priv.h"
#include "ec2.h"
#include "ecp.h"
#include <stdlib.h>
#include <string.h>

/* Allocate memory for a new ECGroup object. */
ECGroup *
ECGroup_new()
{
	mp_err res = MP_OKAY;
	ECGroup *group;
	group = (ECGroup *) malloc(sizeof(ECGroup));
	if (group == NULL)
		return NULL;
	group->constructed = MP_YES;
        group->meth = NULL;
	group->text = NULL;
	MP_DIGITS(&group->curvea) = 0;
	MP_DIGITS(&group->curveb) = 0;
	MP_DIGITS(&group->genx) = 0;
	MP_DIGITS(&group->geny) = 0;
	MP_DIGITS(&group->order) = 0;
	group->base_point_mul = NULL;
	group->points_mul = NULL;
	group->validate_point = NULL;
	group->extra1 = NULL;
	group->extra2 = NULL;
	group->extra_free = NULL;
	MP_CHECKOK(mp_init(&group->curvea));
	MP_CHECKOK(mp_init(&group->curveb));
	MP_CHECKOK(mp_init(&group->genx));
	MP_CHECKOK(mp_init(&group->geny));
	MP_CHECKOK(mp_init(&group->order));

  CLEANUP:
	if (res != MP_OKAY) {
		ECGroup_free(group);
		return NULL;
	}
	return group;
}

/* Construct a generic ECGroup for elliptic curves over prime fields. */
ECGroup *
ECGroup_consGFp(const mp_int *irr, const mp_int *curvea,
				const mp_int *curveb, const mp_int *genx,
				const mp_int *geny, const mp_int *order, int cofactor)
{
	mp_err res = MP_OKAY;
	ECGroup *group = NULL;

	group = ECGroup_new();
	if (group == NULL)
		return NULL;

	group->meth = GFMethod_consGFp(irr);
	if (group->meth == NULL) {
		res = MP_MEM;
		goto CLEANUP;
	}
	MP_CHECKOK(mp_copy(curvea, &group->curvea));
	MP_CHECKOK(mp_copy(curveb, &group->curveb));
	MP_CHECKOK(mp_copy(genx, &group->genx));
	MP_CHECKOK(mp_copy(geny, &group->geny));
	MP_CHECKOK(mp_copy(order, &group->order));
	group->cofactor = cofactor;
	group->point_add = &ec_GFp_pt_add_aff;
	group->point_sub = &ec_GFp_pt_sub_aff;
	group->point_dbl = &ec_GFp_pt_dbl_aff;
	group->point_mul = &ec_GFp_pt_mul_jm_wNAF;
	group->base_point_mul = NULL;
	group->points_mul = &ec_GFp_pts_mul_jac;
	group->validate_point = &ec_GFp_validate_point;

  CLEANUP:
	if (res != MP_OKAY) {
		ECGroup_free(group);
		return NULL;
	}
	return group;
}

/* Construct a generic ECGroup for elliptic curves over prime fields with
 * field arithmetic implemented in Montgomery coordinates. */
ECGroup *
ECGroup_consGFp_mont(const mp_int *irr, const mp_int *curvea,
					 const mp_int *curveb, const mp_int *genx,
					 const mp_int *geny, const mp_int *order, int cofactor)
{
	mp_err res = MP_OKAY;
	ECGroup *group = NULL;

	group = ECGroup_new();
	if (group == NULL)
		return NULL;

	group->meth = GFMethod_consGFp_mont(irr);
	if (group->meth == NULL) {
		res = MP_MEM;
		goto CLEANUP;
	}
	MP_CHECKOK(group->meth->
			   field_enc(curvea, &group->curvea, group->meth));
	MP_CHECKOK(group->meth->
			   field_enc(curveb, &group->curveb, group->meth));
	MP_CHECKOK(group->meth->field_enc(genx, &group->genx, group->meth));
	MP_CHECKOK(group->meth->field_enc(geny, &group->geny, group->meth));
	MP_CHECKOK(mp_copy(order, &group->order));
	group->cofactor = cofactor;
	group->point_add = &ec_GFp_pt_add_aff;
	group->point_sub = &ec_GFp_pt_sub_aff;
	group->point_dbl = &ec_GFp_pt_dbl_aff;
	group->point_mul = &ec_GFp_pt_mul_jm_wNAF;
	group->base_point_mul = NULL;
	group->points_mul = &ec_GFp_pts_mul_jac;
	group->validate_point = &ec_GFp_validate_point;

  CLEANUP:
	if (res != MP_OKAY) {
		ECGroup_free(group);
		return NULL;
	}
	return group;
}

#ifdef NSS_ECC_MORE_THAN_SUITE_B
/* Construct a generic ECGroup for elliptic curves over binary polynomial
 * fields. */
ECGroup *
ECGroup_consGF2m(const mp_int *irr, const unsigned int irr_arr[5],
				 const mp_int *curvea, const mp_int *curveb,
				 const mp_int *genx, const mp_int *geny,
				 const mp_int *order, int cofactor)
{
	mp_err res = MP_OKAY;
	ECGroup *group = NULL;

	group = ECGroup_new();
	if (group == NULL)
		return NULL;

	group->meth = GFMethod_consGF2m(irr, irr_arr);
	if (group->meth == NULL) {
		res = MP_MEM;
		goto CLEANUP;
	}
	MP_CHECKOK(mp_copy(curvea, &group->curvea));
	MP_CHECKOK(mp_copy(curveb, &group->curveb));
	MP_CHECKOK(mp_copy(genx, &group->genx));
	MP_CHECKOK(mp_copy(geny, &group->geny));
	MP_CHECKOK(mp_copy(order, &group->order));
	group->cofactor = cofactor;
	group->point_add = &ec_GF2m_pt_add_aff;
	group->point_sub = &ec_GF2m_pt_sub_aff;
	group->point_dbl = &ec_GF2m_pt_dbl_aff;
	group->point_mul = &ec_GF2m_pt_mul_mont;
	group->base_point_mul = NULL;
	group->points_mul = &ec_pts_mul_basic;
	group->validate_point = &ec_GF2m_validate_point;

  CLEANUP:
	if (res != MP_OKAY) {
		ECGroup_free(group);
		return NULL;
	}
	return group;
}
#endif

/* Construct ECGroup from hex parameters and name, if any. Called by
 * ECGroup_fromHex and ECGroup_fromName. */
ECGroup *
ecgroup_fromNameAndHex(const ECCurveName name,
					   const ECCurveParams * params)
{
	mp_int irr, curvea, curveb, genx, geny, order;
	int bits;
	ECGroup *group = NULL;
	mp_err res = MP_OKAY;

	/* initialize values */
	MP_DIGITS(&irr) = 0;
	MP_DIGITS(&curvea) = 0;
	MP_DIGITS(&curveb) = 0;
	MP_DIGITS(&genx) = 0;
	MP_DIGITS(&geny) = 0;
	MP_DIGITS(&order) = 0;
	MP_CHECKOK(mp_init(&irr));
	MP_CHECKOK(mp_init(&curvea));
	MP_CHECKOK(mp_init(&curveb));
	MP_CHECKOK(mp_init(&genx));
	MP_CHECKOK(mp_init(&geny));
	MP_CHECKOK(mp_init(&order));
	MP_CHECKOK(mp_read_radix(&irr, params->irr, 16));
	MP_CHECKOK(mp_read_radix(&curvea, params->curvea, 16));
	MP_CHECKOK(mp_read_radix(&curveb, params->curveb, 16));
	MP_CHECKOK(mp_read_radix(&genx, params->genx, 16));
	MP_CHECKOK(mp_read_radix(&geny, params->geny, 16));
	MP_CHECKOK(mp_read_radix(&order, params->order, 16));

	/* determine number of bits */
	bits = mpl_significant_bits(&irr) - 1;
	if (bits < MP_OKAY) {
		res = bits;
		goto CLEANUP;
	}

	/* determine which optimizations (if any) to use */
	if (params->field == ECField_GFp) {
	    switch (name) {
#ifdef NSS_ECC_MORE_THAN_SUITE_B
#ifdef ECL_USE_FP
		case ECCurve_SECG_PRIME_160R1:
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_secp160r1_fp(group));
			break;
#endif
		case ECCurve_SECG_PRIME_192R1:
#ifdef ECL_USE_FP
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_nistp192_fp(group));
#else
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_gfp192(group, name));
#endif
			break;
		case ECCurve_SECG_PRIME_224R1:
#ifdef ECL_USE_FP
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_nistp224_fp(group));
#else
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_gfp224(group, name));
#endif
			break;
#endif /* NSS_ECC_MORE_THAN_SUITE_B */
		case ECCurve_SECG_PRIME_256R1:
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_gfp256(group, name));
			MP_CHECKOK(ec_group_set_gfp256_32(group, name));
			break;
		case ECCurve_SECG_PRIME_521R1:
			group =
				ECGroup_consGFp(&irr, &curvea, &curveb, &genx, &geny,
								&order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
			MP_CHECKOK(ec_group_set_gfp521(group, name));
			break;
		default:
			/* use generic arithmetic */
			group =
				ECGroup_consGFp_mont(&irr, &curvea, &curveb, &genx, &geny,
									 &order, params->cofactor);
			if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
		}
#ifdef NSS_ECC_MORE_THAN_SUITE_B
	} else if (params->field == ECField_GF2m) {
		group = ECGroup_consGF2m(&irr, NULL, &curvea, &curveb, &genx, &geny, &order, params->cofactor);
		if (group == NULL) { res = MP_UNDEF; goto CLEANUP; }
		if ((name == ECCurve_NIST_K163) ||
		    (name == ECCurve_NIST_B163) ||
		    (name == ECCurve_SECG_CHAR2_163R1)) {
			MP_CHECKOK(ec_group_set_gf2m163(group, name));
		} else if ((name == ECCurve_SECG_CHAR2_193R1) ||
		           (name == ECCurve_SECG_CHAR2_193R2)) {
			MP_CHECKOK(ec_group_set_gf2m193(group, name));
		} else if ((name == ECCurve_NIST_K233) ||
		           (name == ECCurve_NIST_B233)) {
			MP_CHECKOK(ec_group_set_gf2m233(group, name));
		}
#endif
	} else {
		res = MP_UNDEF;
		goto CLEANUP;
	}

	/* set name, if any */
	if ((group != NULL) && (params->text != NULL)) {
		group->text = strdup(params->text);
		if (group->text == NULL) {
			res = MP_MEM;
		}
	}

  CLEANUP:
	mp_clear(&irr);
	mp_clear(&curvea);
	mp_clear(&curveb);
	mp_clear(&genx);
	mp_clear(&geny);
	mp_clear(&order);
	if (res != MP_OKAY) {
		ECGroup_free(group);
		return NULL;
	}
	return group;
}

/* Construct ECGroup from hexadecimal representations of parameters. */
ECGroup *
ECGroup_fromHex(const ECCurveParams * params)
{
	return ecgroup_fromNameAndHex(ECCurve_noName, params);
}

/* Construct ECGroup from named parameters. */
ECGroup *
ECGroup_fromName(const ECCurveName name)
{
	ECGroup *group = NULL;
	ECCurveParams *params = NULL;
	mp_err res = MP_OKAY;

	params = EC_GetNamedCurveParams(name);
	if (params == NULL) {
		res = MP_UNDEF;
		goto CLEANUP;
	}

	/* construct actual group */
	group = ecgroup_fromNameAndHex(name, params);
	if (group == NULL) {
		res = MP_UNDEF;
		goto CLEANUP;
	}

  CLEANUP:
	EC_FreeCurveParams(params);
	if (res != MP_OKAY) {
		ECGroup_free(group);
		return NULL;
	}
	return group;
}

/* Validates an EC public key as described in Section 5.2.2 of X9.62. */
mp_err ECPoint_validate(const ECGroup *group, const mp_int *px, const 
					mp_int *py)
{
    /* 1: Verify that publicValue is not the point at infinity */
    /* 2: Verify that the coordinates of publicValue are elements 
     *    of the field.
     */
    /* 3: Verify that publicValue is on the curve. */
    /* 4: Verify that the order of the curve times the publicValue
     *    is the point at infinity.
     */
	return group->validate_point(px, py, group);
}

/* Free the memory allocated (if any) to an ECGroup object. */
void
ECGroup_free(ECGroup *group)
{
	if (group == NULL)
		return;
	GFMethod_free(group->meth);
	if (group->constructed == MP_NO)
		return;
	mp_clear(&group->curvea);
	mp_clear(&group->curveb);
	mp_clear(&group->genx);
	mp_clear(&group->geny);
	mp_clear(&group->order);
	if (group->text != NULL)
		free(group->text);
	if (group->extra_free != NULL)
		group->extra_free(group);
	free(group);
}