/*

 * Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include "internal/cryptlib.h"

#include <openssl/asn1t.h>

#include <openssl/ec.h>

#include <openssl/evp.h>

#include "internal/evp_int.h"

#include "internal/sm2.h"

#include "internal/sm2err.h"

/* EC pkey context structure */

typedef struct {

    /* Key and paramgen group */

    EC_GROUP *gen_group;

    /* message digest */

    const EVP_MD *md;

} SM2_PKEY_CTX;

static int pkey_sm2_init(EVP_PKEY_CTX *ctx)

{

    SM2_PKEY_CTX *dctx;

    if ((dctx = OPENSSL_zalloc(sizeof(*dctx))) == NULL) {

        SM2err(SM2_F_PKEY_SM2_INIT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    ctx->data = dctx;

    return 1;

}

static void pkey_sm2_cleanup(EVP_PKEY_CTX *ctx)

{

    SM2_PKEY_CTX *dctx = ctx->data;

    if (dctx != NULL) {

        EC_GROUP_free(dctx->gen_group);

        OPENSSL_free(dctx);

        ctx->data = NULL;

    }

}

static int pkey_sm2_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)

{

    SM2_PKEY_CTX *dctx, *sctx;

    if (!pkey_sm2_init(dst))

        return 0;

    sctx = src->data;

    dctx = dst->data;

    if (sctx->gen_group != NULL) {

        dctx->gen_group = EC_GROUP_dup(sctx->gen_group);

        if (dctx->gen_group == NULL) {

            pkey_sm2_cleanup(dst);

            return 0;

        }

    }

    dctx->md = sctx->md;

    return 1;

}

static int pkey_sm2_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,

                         const unsigned char *tbs, size_t tbslen)

{

    int ret;

    unsigned int sltmp;

    EC_KEY *ec = ctx->pkey->pkey.ec;

    const int sig_sz = ECDSA_size(ctx->pkey->pkey.ec);

    if (sig_sz <= 0) {

        return 0;

    }

    if (sig == NULL) {

        *siglen = (size_t)sig_sz;

        return 1;

    }

    if (*siglen < (size_t)sig_sz) {

        SM2err(SM2_F_PKEY_SM2_SIGN, SM2_R_BUFFER_TOO_SMALL);

        return 0;

    }

    ret = sm2_sign(tbs, tbslen, sig, &sltmp, ec);

    if (ret <= 0)

        return ret;

    *siglen = (size_t)sltmp;

    return 1;

}

static int pkey_sm2_verify(EVP_PKEY_CTX *ctx,

                           const unsigned char *sig, size_t siglen,

                           const unsigned char *tbs, size_t tbslen)

{

    EC_KEY *ec = ctx->pkey->pkey.ec;

    return sm2_verify(tbs, tbslen, sig, siglen, ec);

}

static int pkey_sm2_encrypt(EVP_PKEY_CTX *ctx,

                            unsigned char *out, size_t *outlen,

                            const unsigned char *in, size_t inlen)

{

    EC_KEY *ec = ctx->pkey->pkey.ec;

    SM2_PKEY_CTX *dctx = ctx->data;

    const EVP_MD *md = (dctx->md == NULL) ? EVP_sm3() : dctx->md;

    if (out == NULL) {

        if (!sm2_ciphertext_size(ec, md, inlen, outlen))

            return -1;

        else

            return 1;

    }

    return sm2_encrypt(ec, md, in, inlen, out, outlen);

}

static int pkey_sm2_decrypt(EVP_PKEY_CTX *ctx,

                            unsigned char *out, size_t *outlen,

                            const unsigned char *in, size_t inlen)

{

    EC_KEY *ec = ctx->pkey->pkey.ec;

    SM2_PKEY_CTX *dctx = ctx->data;

    const EVP_MD *md = (dctx->md == NULL) ? EVP_sm3() : dctx->md;

    if (out == NULL) {

        if (!sm2_plaintext_size(ec, md, inlen, outlen))

            return -1;

        else

            return 1;

    }

    return sm2_decrypt(ec, md, in, inlen, out, outlen);

}

static int pkey_sm2_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)

{

    SM2_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) {

            SM2err(SM2_F_PKEY_SM2_CTRL, SM2_R_INVALID_CURVE);

            return 0;

        }

        EC_GROUP_free(dctx->gen_group);

        dctx->gen_group = group;

        return 1;

    case EVP_PKEY_CTRL_EC_PARAM_ENC:

        if (dctx->gen_group == NULL) {

            SM2err(SM2_F_PKEY_SM2_CTRL, SM2_R_NO_PARAMETERS_SET);

            return 0;

        }

        EC_GROUP_set_asn1_flag(dctx->gen_group, p1);

        return 1;

    case EVP_PKEY_CTRL_MD:

        dctx->md = p2;

        return 1;

    case EVP_PKEY_CTRL_GET_MD:

        *(const EVP_MD **)p2 = dctx->md;

        return 1;

    default:

        return -2;

    }

}

static int pkey_sm2_ctrl_str(EVP_PKEY_CTX *ctx,

                             const char *type, const char *value)

{

    if (strcmp(type, "ec_paramgen_curve") == 0) {

        int nid = NID_undef;

        if (((nid = EC_curve_nist2nid(value)) == NID_undef)

            && ((nid = OBJ_sn2nid(value)) == NID_undef)

            && ((nid = OBJ_ln2nid(value)) == NID_undef)) {

            SM2err(SM2_F_PKEY_SM2_CTRL_STR, SM2_R_INVALID_CURVE);

            return 0;

        }

        return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);

    } else if (strcmp(type, "ec_param_enc") == 0) {

        int param_enc;

        if (strcmp(value, "explicit") == 0)

            param_enc = 0;

        else if (strcmp(value, "named_curve") == 0)

            param_enc = OPENSSL_EC_NAMED_CURVE;

        else

            return -2;

        return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);

    }

    return -2;

}

const EVP_PKEY_METHOD sm2_pkey_meth = {

    EVP_PKEY_SM2,

    0,

    pkey_sm2_init,

    pkey_sm2_copy,

    pkey_sm2_cleanup,

    0,

    0,

    0,

    0,

    0,

    pkey_sm2_sign,

    0,

    pkey_sm2_verify,

    0, 0,

    0, 0, 0, 0,

    0,

    pkey_sm2_encrypt,

    0,

    pkey_sm2_decrypt,

    0,

    0,

    pkey_sm2_ctrl,

    pkey_sm2_ctrl_str

};