//===- FuzzerSHA1.h - Private copy of the SHA1 implementation ---*- C++ -* ===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// 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"
#include "FuzzerPlatform.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
// Windows is always little endian and MSVC doesn't have <endian.h>
#elif defined __LITTLE_ENDIAN__ || LIBFUZZER_WINDOWS
/* 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
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);
}
} // namespace fuzzer
