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libfuzzer.cc
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libfuzzer.cc
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// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdio.h>
#include <unistd.h>
#include <exception>
#include <iostream>
#include <sstream>
#include "atheris.h"
#include "macros.h"
#include "tracer.h"
#include "util.h"
using UserCb = int (*)(const uint8_t* Data, size_t Size);
extern "C" int LLVMFuzzerRunDriver(int* argc, char*** argv,
int (*UserCb)(const uint8_t* Data,
size_t Size));
namespace atheris {
namespace py = pybind11;
namespace {
std::function<void(py::bytes data)>& test_one_input_global =
*new std::function<void(py::bytes data)>([](py::bytes data) -> void {
std::cerr << "You must call Setup() before Fuzz()." << std::endl;
_exit(-1);
});
std::vector<std::string>& args_global = *new std::vector<std::string>();
bool setup_called = false;
} // namespace
NO_SANITIZE
void Init() {
if (!&LLVMFuzzerRunDriver) {
throw std::runtime_error(
"LLVMFuzzerRunDriver symbol not found. This means "
"you had an old version of Clang installed when "
"you built Atheris.");
}
}
NO_SANITIZE
std::vector<std::string> Setup(
const std::vector<std::string>& args,
const std::function<void(py::bytes data)>& test_one_input,
py::kwargs kwargs) {
if (setup_called) {
std::cerr << Colorize(STDERR_FILENO,
"Setup() must not be called more than once.")
<< std::endl;
exit(1);
}
setup_called = true;
args_global = args;
test_one_input_global = test_one_input;
// Strip libFuzzer arguments (single dash).
std::vector<std::string> ret;
for (const std::string& arg : args) {
if (arg.size() > 1 && arg[0] == '-' && arg[1] != '-') {
continue;
}
ret.push_back(arg);
}
bool enable_python_coverage = true;
if (kwargs.contains("enable_python_coverage")) {
enable_python_coverage = kwargs["enable_python_coverage"].cast<bool>();
}
#ifdef HAS_OPCODE_TRACE
bool enable_python_opcode_coverage = true;
#else
bool enable_python_opcode_coverage = false;
#endif
if (kwargs.contains("enable_python_opcode_coverage")) {
enable_python_opcode_coverage =
kwargs["enable_python_opcode_coverage"].cast<bool>();
}
if (enable_python_coverage) {
SetupTracer(enable_python_opcode_coverage);
}
return ret;
}
NO_SANITIZE
int TestOneInput(const uint8_t* data, size_t size) {
try {
test_one_input_global(py::bytes(reinterpret_cast<const char*>(data), size));
return 0;
} catch (py::error_already_set& ex) {
std::string exception_type = GetExceptionType(ex);
if (exception_type == "KeyboardInterrupt" ||
exception_type == "exceptions.KeyboardInterrupt") {
// Unfortunately, this can occur in the transition between Python and C++,
// in which case it's impossible to catch in Python. Exit here instead.
std::cout << Colorize(STDOUT_FILENO, "KeyboardInterrupt: stopping.")
<< std::endl;
_exit(130); // Prevent libFuzzer from thinking this is a crash.
}
std::cout << Colorize(STDOUT_FILENO,
"\n === Uncaught Python exception: ===\n");
PrintPythonException(ex, std::cout);
exit(-1);
}
}
NO_SANITIZE
void Fuzz() {
if (!setup_called) {
std::cerr << Colorize(STDERR_FILENO,
"Setup() must be called before Fuzz() can be called.")
<< std::endl;
exit(1);
}
std::vector<char*> args;
args.reserve(args_global.size() + 1);
for (const std::string& arg : args_global) {
args.push_back(const_cast<char*>(arg.c_str()));
}
args.push_back(nullptr);
char** args_ptr = &args[0];
int args_size = args_global.size();
exit(LLVMFuzzerRunDriver(&args_size, &args_ptr, &TestOneInput));
}
} // namespace atheris