text: /*
   * 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;
      size_t allocsize;
  
      /* 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;
  
      /*
       * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in
       * uint64_t and also size_t (their sizes are unrelated).
       * 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;
      }
      /* check total allocated size fits in size_t */
      if (Blen > SIZE_MAX - Vlen)
          return 0;
  
      allocsize = (size_t)(Blen + Vlen);
  
      if (maxmem == 0)
          maxmem = SCRYPT_MAX_MEM;
  
      if (allocsize > 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(allocsize);
      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(),
                            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, 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, allocsize);
      return rv;
  }
  #endif
  