add libfuzzer custom mutator, minor enhancements and fixes

1 files changed, 269 insertions, 0 deletions

diff --git a/custom_mutators/libfuzzer/FuzzerSHA1.cpp b/custom_mutators/libfuzzer/FuzzerSHA1.cpp
new file mode 100644
index 00000000..0a58b661
--- /dev/null
+++ b/custom_mutators/libfuzzer/FuzzerSHA1.cpp
@@ -0,0 +1,269 @@
+//===- 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
+