/*

 * 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 "crypto/evp.h"

#include "crypto/sm2.h"

#include "crypto/sm2err.h"

/* EC pkey context structure */

typedef struct {

    /* Key and paramgen group */

    EC_GROUP *gen_group;

    /* message digest */

    const EVP_MD *md;

    /* Distinguishing Identifier, ISO/IEC 15946-3 */

    uint8_t *id;

    size_t id_len;

    /* id_set indicates if the 'id' field is set (1) or not (0) */

    int id_set;

} SM2_PKEY_CTX;

static int pkey_sm2_init(EVP_PKEY_CTX *ctx)

{

    SM2_PKEY_CTX *smctx;

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

        SM2err(SM2_F_PKEY_SM2_INIT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    ctx->data = smctx;

    return 1;

}

static void pkey_sm2_cleanup(EVP_PKEY_CTX *ctx)

{

    SM2_PKEY_CTX *smctx = ctx->data;

    if (smctx != NULL) {

        EC_GROUP_free(smctx->gen_group);

        OPENSSL_free(smctx->id);

        OPENSSL_free(smctx);

        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;

        }

    }

    if (sctx->id != NULL) {

        dctx->id = OPENSSL_malloc(sctx->id_len);

        if (dctx->id == NULL) {

            SM2err(SM2_F_PKEY_SM2_COPY, ERR_R_MALLOC_FAILURE);

            pkey_sm2_cleanup(dst);

            return 0;

        }

        memcpy(dctx->id, sctx->id, sctx->id_len);

    }

    dctx->id_len = sctx->id_len;

    dctx->id_set = sctx->id_set;

    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 *smctx = ctx->data;

    EC_GROUP *group;

    uint8_t *tmp_id;

    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(smctx->gen_group);

        smctx->gen_group = group;

        return 1;

    case EVP_PKEY_CTRL_EC_PARAM_ENC:

        if (smctx->gen_group == NULL) {

            SM2err(SM2_F_PKEY_SM2_CTRL, SM2_R_NO_PARAMETERS_SET);

            return 0;

        }

        EC_GROUP_set_asn1_flag(smctx->gen_group, p1);

        return 1;

    case EVP_PKEY_CTRL_MD:

        smctx->md = p2;

        return 1;

    case EVP_PKEY_CTRL_GET_MD:

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

        return 1;

    case EVP_PKEY_CTRL_SET1_ID:

        if (p1 > 0) {

            tmp_id = OPENSSL_malloc(p1);

            if (tmp_id == NULL) {

                SM2err(SM2_F_PKEY_SM2_CTRL, ERR_R_MALLOC_FAILURE);

                return 0;

            }

            memcpy(tmp_id, p2, p1);

            OPENSSL_free(smctx->id);

            smctx->id = tmp_id;

        } else {

            /* set null-ID */

            OPENSSL_free(smctx->id);

            smctx->id = NULL;

        }

        smctx->id_len = (size_t)p1;

        smctx->id_set = 1;

        return 1;

    case EVP_PKEY_CTRL_GET1_ID:

        memcpy(p2, smctx->id, smctx->id_len);

        return 1;

    case EVP_PKEY_CTRL_GET1_ID_LEN:

        *(size_t *)p2 = smctx->id_len;

        return 1;

    case EVP_PKEY_CTRL_DIGESTINIT:

        /* nothing to be inited, this is to suppress the error... */

        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;

}

static int pkey_sm2_digest_custom(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)

{

    uint8_t z[EVP_MAX_MD_SIZE];

    SM2_PKEY_CTX *smctx = ctx->data;

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

    const EVP_MD *md = EVP_MD_CTX_md(mctx);

    int mdlen = EVP_MD_size(md);

    if (!smctx->id_set) {

        /*

         * An ID value must be set. The specifications are not clear whether a

         * NULL is allowed. We only allow it if set explicitly for maximum

         * flexibility.

         */

        SM2err(SM2_F_PKEY_SM2_DIGEST_CUSTOM, SM2_R_ID_NOT_SET);

        return 0;

    }

    if (mdlen < 0) {

        SM2err(SM2_F_PKEY_SM2_DIGEST_CUSTOM, SM2_R_INVALID_DIGEST);

        return 0;

    }

    /* get hashed prefix 'z' of tbs message */

    if (!sm2_compute_z_digest(z, md, smctx->id, smctx->id_len, ec))

        return 0;

    return EVP_DigestUpdate(mctx, z, (size_t)mdlen);

}

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,

    0, 0,

    0, 0, 0,

    pkey_sm2_digest_custom

};

const EVP_PKEY_METHOD *sm2_pkey_method(void)

{

    return &sm2_pkey_meth;

}