/*

 * 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 <stddef.h>

#include <stdio.h>

#include <string.h>

#include <openssl/evp.h>

#include <openssl/err.h>

#include "internal/numbers.h"

#ifndef OPENSSL_NO_SCRYPT

#define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))

static void salsa208_word_specification(uint32_t inout[16])

{

    int i;

    uint32_t x[16];

    memcpy(x, inout, sizeof(x));

    for (i = 8; i > 0; i -= 2) {

        x[4] ^= R(x[0] + x[12], 7);

        x[8] ^= R(x[4] + x[0], 9);

        x[12] ^= R(x[8] + x[4], 13);

        x[0] ^= R(x[12] + x[8], 18);

        x[9] ^= R(x[5] + x[1], 7);

        x[13] ^= R(x[9] + x[5], 9);

        x[1] ^= R(x[13] + x[9], 13);

        x[5] ^= R(x[1] + x[13], 18);

        x[14] ^= R(x[10] + x[6], 7);

        x[2] ^= R(x[14] + x[10], 9);

        x[6] ^= R(x[2] + x[14], 13);

        x[10] ^= R(x[6] + x[2], 18);

        x[3] ^= R(x[15] + x[11], 7);

        x[7] ^= R(x[3] + x[15], 9);

        x[11] ^= R(x[7] + x[3], 13);

        x[15] ^= R(x[11] + x[7], 18);

        x[1] ^= R(x[0] + x[3], 7);

        x[2] ^= R(x[1] + x[0], 9);

        x[3] ^= R(x[2] + x[1], 13);

        x[0] ^= R(x[3] + x[2], 18);

        x[6] ^= R(x[5] + x[4], 7);

        x[7] ^= R(x[6] + x[5], 9);

        x[4] ^= R(x[7] + x[6], 13);

        x[5] ^= R(x[4] + x[7], 18);

        x[11] ^= R(x[10] + x[9], 7);

        x[8] ^= R(x[11] + x[10], 9);

        x[9] ^= R(x[8] + x[11], 13);

        x[10] ^= R(x[9] + x[8], 18);

        x[12] ^= R(x[15] + x[14], 7);

        x[13] ^= R(x[12] + x[15], 9);

        x[14] ^= R(x[13] + x[12], 13);

        x[15] ^= R(x[14] + x[13], 18);

    }

    for (i = 0; i < 16; ++i)

        inout[i] += x[i];

    OPENSSL_cleanse(x, sizeof(x));

}

static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)

{

    uint64_t i, j;

    uint32_t X[16], *pB;

    memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));

    pB = B;

    for (i = 0; i < r * 2; i++) {

        for (j = 0; j < 16; j++)

            X[j] ^= *pB++;

        salsa208_word_specification(X);

        memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));

    }

    OPENSSL_cleanse(X, sizeof(X));

}

static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,

                        uint32_t *X, uint32_t *T, uint32_t *V)

{

    unsigned char *pB;

    uint32_t *pV;

    uint64_t i, k;

    /* Convert from little endian input */

    for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {

        *pV = *pB++;

        *pV |= *pB++ << 8;

        *pV |= *pB++ << 16;

        *pV |= (uint32_t)*pB++ << 24;

    }

    for (i = 1; i < N; i++, pV += 32 * r)

        scryptBlockMix(pV, pV - 32 * r, r);

    scryptBlockMix(X, V + (N - 1) * 32 * r, r);

    for (i = 0; i < N; i++) {

        uint32_t j;

        j = X[16 * (2 * r - 1)] % N;

        pV = V + 32 * r * j;

        for (k = 0; k < 32 * r; k++)

            T[k] = X[k] ^ *pV++;

        scryptBlockMix(X, T, r);

    }

    /* Convert output to little endian */

    for (i = 0, pB = B; i < 32 * r; i++) {

        uint32_t xtmp = X[i];

        *pB++ = xtmp & 0xff;

        *pB++ = (xtmp >> 8) & 0xff;

        *pB++ = (xtmp >> 16) & 0xff;

        *pB++ = (xtmp >> 24) & 0xff;

    }

}

#ifndef SIZE_MAX

# define SIZE_MAX    ((size_t)-1)

#endif

/*

 * Maximum power of two that will fit in uint64_t: this should work on

 * most (all?) platforms.

 */

#define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)

/*

 * Maximum value of p * r:

 * p <= ((2^32-1) * hLen) / MFLen =>

 * p <= ((2^32-1) * 32) / (128 * r) =>

 * p * r <= (2^30-1)

 *

 */

#define SCRYPT_PR_MAX   ((1 << 30) - 1)

/*

 * 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)

{

    int rv = 0;

    unsigned char *B;

    uint32_t *X, *V, *T;

    uint64_t i, Blen, Vlen;

    /* Sanity check parameters */

    /* initial check, r,p must be non zero, N >= 2 and a power of 2 */

    if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))

        return 0;

    /* Check p * r < SCRYPT_PR_MAX avoiding overflow */

    if (p > SCRYPT_PR_MAX / r) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_MEMORY_LIMIT_EXCEEDED);

        return 0;

    }

    /*

     * Need to check N: if 2^(128 * r / 8) overflows limit this is

     * automatically satisfied since N <= UINT64_MAX.

     */

    if (16 * r <= LOG2_UINT64_MAX) {

        if (N >= (((uint64_t)1) << (16 * r))) {

            EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_MEMORY_LIMIT_EXCEEDED);

            return 0;

        }

    }

    /* Memory checks: check total allocated buffer size fits in uint64_t */

    /*

     * B size in section 5 step 1.S

     * Note: we know p * 128 * r < UINT64_MAX because we already checked

     * p * r < SCRYPT_PR_MAX

     */

    Blen = p * 128 * r;

    /*

     * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would

     * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]

     */

    if (Blen > INT_MAX) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_MEMORY_LIMIT_EXCEEDED);

        return 0;

    }

    /*

     * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t

     * This is combined size V, X and T (section 4)

     */

    i = UINT64_MAX / (32 * sizeof(uint32_t));

    if (N + 2 > i / r) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_MEMORY_LIMIT_EXCEEDED);

        return 0;

    }

    Vlen = 32 * r * (N + 2) * sizeof(uint32_t);

    /* check total allocated size fits in uint64_t */

    if (Blen > UINT64_MAX - Vlen) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_MEMORY_LIMIT_EXCEEDED);

        return 0;

    }

    if (maxmem == 0)

        maxmem = SCRYPT_MAX_MEM;

    /* Check that the maximum memory doesn't exceed a size_t limits */

    if (maxmem > SIZE_MAX)

        maxmem = SIZE_MAX;

    if (Blen + Vlen > maxmem) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_MEMORY_LIMIT_EXCEEDED);

        return 0;

    }

    /* If no key return to indicate parameters are OK */

    if (key == NULL)

        return 1;

    B = OPENSSL_malloc((size_t)(Blen + Vlen));

    if (B == NULL) {

        EVPerr(EVP_F_EVP_PBE_SCRYPT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    X = (uint32_t *)(B + Blen);

    T = X + 32 * r;

    V = T + 32 * r;

    if (PKCS5_PBKDF2_HMAC(pass, passlen, salt, saltlen, 1, EVP_sha256(),

                          (int)Blen, B) == 0)

        goto err;

    for (i = 0; i < p; i++)

        scryptROMix(B + 128 * r * i, r, N, X, T, V);

    if (PKCS5_PBKDF2_HMAC(pass, passlen, B, (int)Blen, 1, EVP_sha256(),

                          keylen, key) == 0)

        goto err;

    rv = 1;

 err:

    if (rv == 0)

        EVPerr(EVP_F_EVP_PBE_SCRYPT, EVP_R_PBKDF2_ERROR);

    OPENSSL_clear_free(B, (size_t)(Blen + Vlen));

    return rv;

}

#endif