/*

 * Copyright 2015-2018 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 <openssl/evp.h>

#include <openssl/err.h>

#include <openssl/kdf.h>

#ifndef OPENSSL_NO_SCRYPT

/*

 * Maximum permitted memory allow this to be overridden with Configuration

 * option: e.g. -DSCRYPT_MAX_MEM=0 for maximum possible.

 */

#ifdef SCRYPT_MAX_MEM

# if SCRYPT_MAX_MEM == 0

#  undef SCRYPT_MAX_MEM

/*

 * Although we could theoretically allocate SIZE_MAX memory that would leave

 * no memory available for anything else so set limit as half that.

 */

#  define SCRYPT_MAX_MEM (SIZE_MAX/2)

# endif

#else

/* Default memory limit: 32 MB */

# define SCRYPT_MAX_MEM  (1024 * 1024 * 32)

#endif

int EVP_PBE_scrypt(const char *pass, size_t passlen,

                   const unsigned char *salt, size_t saltlen,

                   uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,

                   unsigned char *key, size_t keylen)

{

    const char *empty = "";

    int rv = 1;

    EVP_KDF_CTX *kctx;

    if (r > UINT32_MAX || p > UINT32_MAX) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_PARAMETER_TOO_LARGE);

        return 0;

    }

    /* Maintain existing behaviour. */

    if (pass == NULL) {

        pass = empty;

        passlen = 0;

    }

    if (salt == NULL) {

        salt = (const unsigned char *)empty;

        saltlen = 0;

    }

    if (maxmem == 0)

        maxmem = SCRYPT_MAX_MEM;

    kctx = EVP_KDF_CTX_new_id(EVP_KDF_SCRYPT);

    if (kctx == NULL)

        return 0;

    if (EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_PASS, pass, (size_t)passlen) != 1

            || EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_SALT,

                            salt, (size_t)saltlen) != 1

            || EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_SCRYPT_N, N) != 1

            || EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_SCRYPT_R, (uint32_t)r) != 1

            || EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_SCRYPT_P, (uint32_t)p) != 1

            || EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_MAXMEM_BYTES, maxmem) != 1

            || EVP_KDF_derive(kctx, key, keylen) != 1)

        rv = 0;

    EVP_KDF_CTX_free(kctx);

    return rv;

}

#endif