/*

 * Copyright 2006-2019 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 <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/asn1t.h>

#include <openssl/x509.h>

#include <openssl/ec.h>

#include "ec_local.h"

#include <openssl/evp.h>

#include "crypto/evp.h"

/* EC pkey context structure */

typedef struct {

    /* Key and paramgen group */

    EC_GROUP *gen_group;

    /* message digest */

    const EVP_MD *md;

    /* Duplicate key if custom cofactor needed */

    EC_KEY *co_key;

    /* Cofactor mode */

    signed char cofactor_mode;

    /* KDF (if any) to use for ECDH */

    char kdf_type;

    /* Message digest to use for key derivation */

    const EVP_MD *kdf_md;

    /* User key material */

    unsigned char *kdf_ukm;

    size_t kdf_ukmlen;

    /* KDF output length */

    size_t kdf_outlen;

} EC_PKEY_CTX;

static int pkey_ec_init(EVP_PKEY_CTX *ctx)

{

    EC_PKEY_CTX *dctx;

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

        ECerr(EC_F_PKEY_EC_INIT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    dctx->cofactor_mode = -1;

    dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE;

    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;

    if (sctx->co_key) {

        dctx->co_key = EC_KEY_dup(sctx->co_key);

        if (!dctx->co_key)

            return 0;

    }

    dctx->kdf_type = sctx->kdf_type;

    dctx->kdf_md = sctx->kdf_md;

    dctx->kdf_outlen = sctx->kdf_outlen;

    if (sctx->kdf_ukm) {

        dctx->kdf_ukm = OPENSSL_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen);

        if (!dctx->kdf_ukm)

            return 0;

    } else

        dctx->kdf_ukm = NULL;

    dctx->kdf_ukmlen = sctx->kdf_ukmlen;

    return 1;

}

static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)

{

    EC_PKEY_CTX *dctx = ctx->data;

    if (dctx != NULL) {

        EC_GROUP_free(dctx->gen_group);

        EC_KEY_free(dctx->co_key);

        OPENSSL_free(dctx->kdf_ukm);

        OPENSSL_free(dctx);

        ctx->data = NULL;

    }

}

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;

    const int sig_sz = ECDSA_size(ec);

    /* ensure cast to size_t is safe */

    if (!ossl_assert(sig_sz > 0))

        return 0;

    if (sig == NULL) {

        *siglen = (size_t)sig_sz;

        return 1;

    }

    if (*siglen < (size_t)sig_sz) {

        ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);

        return 0;

    }

    type = (dctx->md != NULL) ? EVP_MD_type(dctx->md) : 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;

}

#ifndef OPENSSL_NO_EC

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;

    EC_KEY *eckey;

    EC_PKEY_CTX *dctx = ctx->data;

    if (!ctx->pkey || !ctx->peerkey) {

        ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);

        return 0;

    }

    eckey = dctx->co_key ? dctx->co_key : ctx->pkey->pkey.ec;

    if (!key) {

        const EC_GROUP *group;

        group = EC_KEY_get0_group(eckey);

        *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, eckey, 0);

    if (ret <= 0)

        return 0;

    *keylen = ret;

    return 1;

}

static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx,

                              unsigned char *key, size_t *keylen)

{

    EC_PKEY_CTX *dctx = ctx->data;

    unsigned char *ktmp = NULL;

    size_t ktmplen;

    int rv = 0;

    if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE)

        return pkey_ec_derive(ctx, key, keylen);

    if (!key) {

        *keylen = dctx->kdf_outlen;

        return 1;

    }

    if (*keylen != dctx->kdf_outlen)

        return 0;

    if (!pkey_ec_derive(ctx, NULL, &ktmplen))

        return 0;

    if ((ktmp = OPENSSL_malloc(ktmplen)) == NULL) {

        ECerr(EC_F_PKEY_EC_KDF_DERIVE, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    if (!pkey_ec_derive(ctx, ktmp, &ktmplen))

        goto err;

    /* Do KDF stuff */

    if (!ecdh_KDF_X9_63(key, *keylen, ktmp, ktmplen,

                        dctx->kdf_ukm, dctx->kdf_ukmlen, dctx->kdf_md))

        goto err;

    rv = 1;

 err:

    OPENSSL_clear_free(ktmp, ktmplen);

    return rv;

}

#endif

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) {

            ECerr(EC_F_PKEY_EC_CTRL, EC_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) {

            ECerr(EC_F_PKEY_EC_CTRL, EC_R_NO_PARAMETERS_SET);

            return 0;

        }

        EC_GROUP_set_asn1_flag(dctx->gen_group, p1);

        return 1;

#ifndef OPENSSL_NO_EC

    case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:

        if (p1 == -2) {

            if (dctx->cofactor_mode != -1)

                return dctx->cofactor_mode;

            else {

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

                return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 : 0;

            }

        } else if (p1 < -1 || p1 > 1)

            return -2;

        dctx->cofactor_mode = p1;

        if (p1 != -1) {

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

            if (!ec_key->group)

                return -2;

            /* If cofactor is 1 cofactor mode does nothing */

            if (BN_is_one(ec_key->group->cofactor))

                return 1;

            if (!dctx->co_key) {

                dctx->co_key = EC_KEY_dup(ec_key);

                if (!dctx->co_key)

                    return 0;

            }

            if (p1)

                EC_KEY_set_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);

            else

                EC_KEY_clear_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);

        } else {

            EC_KEY_free(dctx->co_key);

            dctx->co_key = NULL;

        }

        return 1;

#endif

    case EVP_PKEY_CTRL_EC_KDF_TYPE:

        if (p1 == -2)

            return dctx->kdf_type;

        if (p1 != EVP_PKEY_ECDH_KDF_NONE && p1 != EVP_PKEY_ECDH_KDF_X9_63)

            return -2;

        dctx->kdf_type = p1;

        return 1;

    case EVP_PKEY_CTRL_EC_KDF_MD:

        dctx->kdf_md = p2;

        return 1;

    case EVP_PKEY_CTRL_GET_EC_KDF_MD:

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

        return 1;

    case EVP_PKEY_CTRL_EC_KDF_OUTLEN:

        if (p1 <= 0)

            return -2;

        dctx->kdf_outlen = (size_t)p1;

        return 1;

    case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN:

        *(int *)p2 = dctx->kdf_outlen;

        return 1;

    case EVP_PKEY_CTRL_EC_KDF_UKM:

        OPENSSL_free(dctx->kdf_ukm);

        dctx->kdf_ukm = p2;

        if (p2)

            dctx->kdf_ukmlen = p1;

        else

            dctx->kdf_ukmlen = 0;

        return 1;

    case EVP_PKEY_CTRL_GET_EC_KDF_UKM:

        *(unsigned char **)p2 = dctx->kdf_ukm;

        return dctx->kdf_ukmlen;

    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 &&

            EVP_MD_type((const EVP_MD *)p2) != NID_sha3_224 &&

            EVP_MD_type((const EVP_MD *)p2) != NID_sha3_256 &&

            EVP_MD_type((const EVP_MD *)p2) != NID_sha3_384 &&

            EVP_MD_type((const EVP_MD *)p2) != NID_sha3_512) {

            ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);

            return 0;

        }

        dctx->md = p2;

        return 1;

    case EVP_PKEY_CTRL_GET_MD:

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

        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") == 0) {

        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) {

            ECerr(EC_F_PKEY_EC_CTRL_STR, EC_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);

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

        const EVP_MD *md;

        if ((md = EVP_get_digestbyname(value)) == NULL) {

            ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);

            return 0;

        }

        return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);

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

        int co_mode;

        co_mode = atoi(value);

        return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);

    }

    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;

    if (dctx->gen_group == NULL) {

        ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);

        return 0;

    }

    ec = EC_KEY_new();

    if (ec == NULL)

        return 0;

    if (!(ret = EC_KEY_set_group(ec, dctx->gen_group))

        || !ossl_assert(ret = EVP_PKEY_assign_EC_KEY(pkey, ec)))

        EC_KEY_free(ec);

    return ret;

}

static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

{

    EC_KEY *ec = NULL;

    EC_PKEY_CTX *dctx = ctx->data;

    int ret;

    if (ctx->pkey == NULL && dctx->gen_group == NULL) {

        ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);

        return 0;

    }

    ec = EC_KEY_new();

    if (ec == NULL)

        return 0;

    if (!ossl_assert(EVP_PKEY_assign_EC_KEY(pkey, ec))) {

        EC_KEY_free(ec);

        return 0;

    }

    /* Note: if error is returned, we count on caller to free pkey->pkey.ec */

    if (ctx->pkey != NULL)

        ret = EVP_PKEY_copy_parameters(pkey, ctx->pkey);

    else

        ret = EC_KEY_set_group(ec, dctx->gen_group);

    return ret ? EC_KEY_generate_key(ec) : 0;

}

const EVP_PKEY_METHOD ec_pkey_meth = {

    EVP_PKEY_EC,

    EVP_PKEY_FLAG_FIPS,

    pkey_ec_init,

    pkey_ec_copy,

    pkey_ec_cleanup,

    0,

    pkey_ec_paramgen,

    0,

    pkey_ec_keygen,

    0,

    pkey_ec_sign,

    0,

    pkey_ec_verify,

    0, 0,

    0, 0, 0, 0,

    0,

    0,

    0,

    0,

    0,

#ifndef OPENSSL_NO_EC

    pkey_ec_kdf_derive,

#else

    0,

#endif

    pkey_ec_ctrl,

    pkey_ec_ctrl_str

};

const EVP_PKEY_METHOD *ec_pkey_method(void)

{

    return &ec_pkey_meth;

}