//===- FuzzerSHA1.h - Private copy of the SHA1 implementation ---*- C++ -* ===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

// This code is taken from public domain

// (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)

// and modified by adding anonymous namespace, adding an interface

// function fuzzer::ComputeSHA1() and removing unnecessary code.

//

// lib/Fuzzer can not use SHA1 implementation from openssl because

// openssl may not be available and because we may be fuzzing openssl itself.

// For the same reason we do not want to depend on SHA1 from LLVM tree.

//===----------------------------------------------------------------------===//

#include "FuzzerSHA1.h"

#include "FuzzerDefs.h"

/* This code is public-domain - it is based on libcrypt

 * placed in the public domain by Wei Dai and other contributors.

 */

#include <iomanip>

#include <sstream>

#include <stdint.h>

#include <string.h>

namespace {  // Added for LibFuzzer

#ifdef __BIG_ENDIAN__

# define SHA_BIG_ENDIAN

#elif defined __LITTLE_ENDIAN__

/* override */

#elif defined __BYTE_ORDER

# if __BYTE_ORDER__ ==  __ORDER_BIG_ENDIAN__

# define SHA_BIG_ENDIAN

# endif

#else // ! defined __LITTLE_ENDIAN__

# include <endian.h> // machine/endian.h

# if __BYTE_ORDER__ ==  __ORDER_BIG_ENDIAN__

#  define SHA_BIG_ENDIAN

# endif

#endif

/* header */

#define HASH_LENGTH 20

#define BLOCK_LENGTH 64

typedef struct sha1nfo {

  uint32_t buffer[BLOCK_LENGTH/4];

  uint32_t state[HASH_LENGTH/4];

  uint32_t byteCount;

  uint8_t bufferOffset;

  uint8_t keyBuffer[BLOCK_LENGTH];

  uint8_t innerHash[HASH_LENGTH];

} sha1nfo;

/* public API - prototypes - TODO: doxygen*/

/**

 */

void sha1_init(sha1nfo *s);

/**

 */

void sha1_writebyte(sha1nfo *s, uint8_t data);

/**

 */

void sha1_write(sha1nfo *s, const char *data, size_t len);

/**

 */

uint8_t* sha1_result(sha1nfo *s);

/* code */

#define SHA1_K0  0x5a827999

#define SHA1_K20 0x6ed9eba1

#define SHA1_K40 0x8f1bbcdc

#define SHA1_K60 0xca62c1d6

void sha1_init(sha1nfo *s) {

  s->state[0] = 0x67452301;

  s->state[1] = 0xefcdab89;

  s->state[2] = 0x98badcfe;

  s->state[3] = 0x10325476;

  s->state[4] = 0xc3d2e1f0;

  s->byteCount = 0;

  s->bufferOffset = 0;

}

uint32_t sha1_rol32(uint32_t number, uint8_t bits) {

  return ((number << bits) | (number >> (32-bits)));

}

void sha1_hashBlock(sha1nfo *s) {

  uint8_t i;

  uint32_t a,b,c,d,e,t;

  a=s->state[0];

  b=s->state[1];

  c=s->state[2];

  d=s->state[3];

  e=s->state[4];

  for (i=0; i<80; i++) {

    if (i>=16) {

      t = s->buffer[(i+13)&15] ^ s->buffer[(i+8)&15] ^ s->buffer[(i+2)&15] ^ s->buffer[i&15];

      s->buffer[i&15] = sha1_rol32(t,1);

    }

    if (i<20) {

      t = (d ^ (b & (c ^ d))) + SHA1_K0;

    } else if (i<40) {

      t = (b ^ c ^ d) + SHA1_K20;

    } else if (i<60) {

      t = ((b & c) | (d & (b | c))) + SHA1_K40;

    } else {

      t = (b ^ c ^ d) + SHA1_K60;

    }

    t+=sha1_rol32(a,5) + e + s->buffer[i&15];

    e=d;

    d=c;

    c=sha1_rol32(b,30);

    b=a;

    a=t;

  }

  s->state[0] += a;

  s->state[1] += b;

  s->state[2] += c;

  s->state[3] += d;

  s->state[4] += e;

}

void sha1_addUncounted(sha1nfo *s, uint8_t data) {

  uint8_t * const b = (uint8_t*) s->buffer;

#ifdef SHA_BIG_ENDIAN

  b[s->bufferOffset] = data;

#else

  b[s->bufferOffset ^ 3] = data;

#endif

  s->bufferOffset++;

  if (s->bufferOffset == BLOCK_LENGTH) {

    sha1_hashBlock(s);

    s->bufferOffset = 0;

  }

}

void sha1_writebyte(sha1nfo *s, uint8_t data) {

  ++s->byteCount;

  sha1_addUncounted(s, data);

}

void sha1_write(sha1nfo *s, const char *data, size_t len) {

  for (;len--;) sha1_writebyte(s, (uint8_t) *data++);

}

void sha1_pad(sha1nfo *s) {

  // Implement SHA-1 padding (fips180-2 §5.1.1)

  // Pad with 0x80 followed by 0x00 until the end of the block

  sha1_addUncounted(s, 0x80);

  while (s->bufferOffset != 56) sha1_addUncounted(s, 0x00);

  // Append length in the last 8 bytes

  sha1_addUncounted(s, 0); // We're only using 32 bit lengths

  sha1_addUncounted(s, 0); // But SHA-1 supports 64 bit lengths

  sha1_addUncounted(s, 0); // So zero pad the top bits

  sha1_addUncounted(s, s->byteCount >> 29); // Shifting to multiply by 8

  sha1_addUncounted(s, s->byteCount >> 21); // as SHA-1 supports bitstreams as well as

  sha1_addUncounted(s, s->byteCount >> 13); // byte.

  sha1_addUncounted(s, s->byteCount >> 5);

  sha1_addUncounted(s, s->byteCount << 3);

}

uint8_t* sha1_result(sha1nfo *s) {

  // Pad to complete the last block

  sha1_pad(s);

#ifndef SHA_BIG_ENDIAN

  // Swap byte order back

  int i;

  for (i=0; i<5; i++) {

    s->state[i]=

        (((s->state[i])<<24)& 0xff000000)

      | (((s->state[i])<<8) & 0x00ff0000)

      | (((s->state[i])>>8) & 0x0000ff00)

      | (((s->state[i])>>24)& 0x000000ff);

  }

#endif

  // Return pointer to hash (20 characters)

  return (uint8_t*) s->state;

}

}  // namespace; Added for LibFuzzer

namespace fuzzer {

// The rest is added for LibFuzzer

void ComputeSHA1(const uint8_t *Data, size_t Len, uint8_t *Out) {

  sha1nfo s;

  sha1_init(&s);

  sha1_write(&s, (const char*)Data, Len);

  memcpy(Out, sha1_result(&s), HASH_LENGTH);

}

std::string Sha1ToString(const uint8_t Sha1[kSHA1NumBytes]) {

  std::stringstream SS;

  for (int i = 0; i < kSHA1NumBytes; i++)

    SS << std::hex << std::setfill('0') << std::setw(2) << (unsigned)Sha1[i];

  return SS.str();

}

std::string Hash(const Unit &U) {

  uint8_t Hash[kSHA1NumBytes];

  ComputeSHA1(U.data(), U.size(), Hash);

  return Sha1ToString(Hash);

}

}