path: root/providers/implementations/kdfs/scrypt.c

/*
 * Copyright 2017-2020 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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 <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/kdf.h>
#include <openssl/err.h>
#include <openssl/core_names.h>
#include "crypto/evp.h"
#include "internal/numbers.h"
#include "prov/implementations.h"
#include "prov/provider_ctx.h"
#include "prov/providercommonerr.h"
#include "prov/implementations.h"

#ifndef OPENSSL_NO_SCRYPT

static OSSL_FUNC_kdf_newctx_fn kdf_scrypt_new;
static OSSL_FUNC_kdf_freectx_fn kdf_scrypt_free;
static OSSL_FUNC_kdf_reset_fn kdf_scrypt_reset;
static OSSL_FUNC_kdf_derive_fn kdf_scrypt_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_scrypt_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn kdf_scrypt_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_scrypt_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn kdf_scrypt_get_ctx_params;

static int scrypt_alg(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, EVP_MD *sha256,
                      OPENSSL_CTX *libctx, const char *propq);

typedef struct {
    void *provctx;
    unsigned char *pass;
    size_t pass_len;
    unsigned char *salt;
    size_t salt_len;
    uint64_t N;
    uint64_t r, p;
    uint64_t maxmem_bytes;
    EVP_MD *sha256;
} KDF_SCRYPT;

static void kdf_scrypt_init(KDF_SCRYPT *ctx);

static void *kdf_scrypt_new(void *provctx)
{
    KDF_SCRYPT *ctx;

    ctx = OPENSSL_zalloc(sizeof(*ctx));
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    ctx->provctx = provctx;
    ctx->sha256 = EVP_MD_fetch(PROV_LIBRARY_CONTEXT_OF(provctx),
                               "sha256", NULL);
    if (ctx->sha256 == NULL) {
        OPENSSL_free(ctx);
        ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA256);
        return NULL;
    }
    kdf_scrypt_init(ctx);
    return ctx;
}

static void kdf_scrypt_free(void *vctx)
{
    KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;

    if (ctx != NULL) {
        EVP_MD_free(ctx->sha256);
        kdf_scrypt_reset(ctx);
        OPENSSL_free(ctx);
    }
}

static void kdf_scrypt_reset(void *vctx)
{
    KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;

    OPENSSL_free(ctx->salt);
    OPENSSL_clear_free(ctx->pass, ctx->pass_len);
    kdf_scrypt_init(ctx);
}

static void kdf_scrypt_init(KDF_SCRYPT *ctx)
{
    /* Default values are the most conservative recommendation given in the
     * original paper of C. Percival. Derivation uses roughly 1 GiB of memory
     * for this parameter choice (approx. 128 * r * N * p bytes).
     */
    ctx->N = 1 << 20;
    ctx->r = 8;
    ctx->p = 1;
    ctx->maxmem_bytes = 1025 * 1024 * 1024;
}

static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
                             const OSSL_PARAM *p)
{
    OPENSSL_clear_free(*buffer, *buflen);
    if (p->data_size == 0) {
        if ((*buffer = OPENSSL_malloc(1)) == NULL) {
            ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
            return 0;
        }
    } else if (p->data != NULL) {
        *buffer = NULL;
        if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
            return 0;
    }
    return 1;
}

static int kdf_scrypt_derive(void *vctx, unsigned char *key,
                             size_t keylen)
{
    KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;

    if (ctx->pass == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
        return 0;
    }

    if (ctx->salt == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
        return 0;
    }

    return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
                      ctx->salt_len, ctx->N, ctx->r, ctx->p,
                      ctx->maxmem_bytes, key, keylen, ctx->sha256,
                      PROV_LIBRARY_CONTEXT_OF(ctx->provctx), NULL);
}

static int is_power_of_two(uint64_t value)
{
    return (value != 0) && ((value & (value - 1)) == 0);
}

static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
    const OSSL_PARAM *p;
    KDF_SCRYPT *ctx = vctx;
    uint64_t u64_value;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
        if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
        if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
        != NULL) {
        if (!OSSL_PARAM_get_uint64(p, &u64_value)
            || u64_value <= 1
            || !is_power_of_two(u64_value))
            return 0;
        ctx->N = u64_value;
    }

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
        != NULL) {
        if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
            return 0;
        ctx->r = u64_value;
    }

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
        != NULL) {
        if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
            return 0;
        ctx->p = u64_value;
    }

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
        != NULL) {
        if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
            return 0;
        ctx->maxmem_bytes = u64_value;
    }
    return 1;
}

static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(void *provctx)
{
    static const OSSL_PARAM known_settable_ctx_params[] = {
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
        OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
        OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
        OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
        OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM,