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// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <test/fuzz/fuzz.h>
#include <netaddress.h>
#include <netbase.h>
#include <test/util/setup_common.h>
#include <util/check.h>
#include <util/fs.h>
#include <util/sock.h>
#include <util/time.h>
#include <csignal>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <exception>
#include <fstream>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <string>
#include <tuple>
#include <unistd.h>
#include <utility>
#include <vector>
#if defined(PROVIDE_FUZZ_MAIN_FUNCTION) && defined(__AFL_FUZZ_INIT)
__AFL_FUZZ_INIT();
#endif
const std::function<void(const std::string&)> G_TEST_LOG_FUN{};
const std::function<std::string()> G_TEST_GET_FULL_NAME{};
/**
* A copy of the command line arguments that start with `--`.
* First `LLVMFuzzerInitialize()` is called, which saves the arguments to `g_args`.
* Later, depending on the fuzz test, `G_TEST_COMMAND_LINE_ARGUMENTS()` may be
* called by `BasicTestingSetup` constructor to fetch those arguments and store
* them in `BasicTestingSetup::m_node::args`.
*/
static std::vector<const char*> g_args;
static void SetArgs(int argc, char** argv) {
for (int i = 1; i < argc; ++i) {
// Only take into account arguments that start with `--`. The others are for the fuzz engine:
// `fuzz -runs=1 fuzz_seed_corpus/address_deserialize_v2 --checkaddrman=5`
if (strlen(argv[i]) > 2 && argv[i][0] == '-' && argv[i][1] == '-') {
g_args.push_back(argv[i]);
}
}
}
const std::function<std::vector<const char*>()> G_TEST_COMMAND_LINE_ARGUMENTS = []() {
return g_args;
};
struct FuzzTarget {
const TypeTestOneInput test_one_input;
const FuzzTargetOptions opts;
};
auto& FuzzTargets()
{
static std::map<std::string_view, FuzzTarget> g_fuzz_targets;
return g_fuzz_targets;
}
void FuzzFrameworkRegisterTarget(std::string_view name, TypeTestOneInput target, FuzzTargetOptions opts)
{
const auto it_ins{FuzzTargets().try_emplace(name, FuzzTarget /* temporary can be dropped in C++20 */ {std::move(target), std::move(opts)})};
Assert(it_ins.second);
}
static std::string_view g_fuzz_target;
static const TypeTestOneInput* g_test_one_input{nullptr};
void initialize()
{
// Terminate immediately if a fuzzing harness ever tries to create a TCP socket.
CreateSock = [](const CService&) -> std::unique_ptr<Sock> { std::terminate(); };
// Terminate immediately if a fuzzing harness ever tries to perform a DNS lookup.
g_dns_lookup = [](const std::string& name, bool allow_lookup) {
if (allow_lookup) {
std::terminate();
}
return WrappedGetAddrInfo(name, false);
};
bool should_exit{false};
if (std::getenv("PRINT_ALL_FUZZ_TARGETS_AND_ABORT")) {
for (const auto& [name, t] : FuzzTargets()) {
if (t.opts.hidden) continue;
std::cout << name << std::endl;
}
should_exit = true;
}
if (const char* out_path = std::getenv("WRITE_ALL_FUZZ_TARGETS_AND_ABORT")) {
std::cout << "Writing all fuzz target names to '" << out_path << "'." << std::endl;
std::ofstream out_stream{out_path, std::ios::binary};
for (const auto& [name, t] : FuzzTargets()) {
if (t.opts.hidden) continue;
out_stream << name << std::endl;
}
should_exit = true;
}
if (should_exit) {
std::exit(EXIT_SUCCESS);
}
if (const auto* env_fuzz{std::getenv("FUZZ")}) {
// To allow for easier fuzz executable binary modification,
static std::string g_copy{env_fuzz}; // create copy to avoid compiler optimizations, and
g_fuzz_target = g_copy.c_str(); // strip string after the first null-char.
} else {
std::cerr << "Must select fuzz target with the FUZZ env var." << std::endl;
std::cerr << "Hint: Set the PRINT_ALL_FUZZ_TARGETS_AND_ABORT=1 env var to see all compiled targets." << std::endl;
std::exit(EXIT_FAILURE);
}
const auto it = FuzzTargets().find(g_fuzz_target);
if (it == FuzzTargets().end()) {
std::cerr << "No fuzz target compiled for " << g_fuzz_target << "." << std::endl;
std::exit(EXIT_FAILURE);
}
Assert(!g_test_one_input);
g_test_one_input = &it->second.test_one_input;
it->second.opts.init();
}
#if defined(PROVIDE_FUZZ_MAIN_FUNCTION)
static bool read_stdin(std::vector<uint8_t>& data)
{
uint8_t buffer[1024];
ssize_t length = 0;
while ((length = read(STDIN_FILENO, buffer, 1024)) > 0) {
data.insert(data.end(), buffer, buffer + length);
}
return length == 0;
}
#endif
#if defined(PROVIDE_FUZZ_MAIN_FUNCTION) && !defined(__AFL_LOOP)
static bool read_file(fs::path p, std::vector<uint8_t>& data)
{
uint8_t buffer[1024];
FILE* f = fsbridge::fopen(p, "rb");
if (f == nullptr) return false;
do {
const size_t length = fread(buffer, sizeof(uint8_t), sizeof(buffer), f);
if (ferror(f)) return false;
data.insert(data.end(), buffer, buffer + length);
} while (!feof(f));
fclose(f);
return true;
}
#endif
#if defined(PROVIDE_FUZZ_MAIN_FUNCTION) && !defined(__AFL_LOOP)
static fs::path g_input_path;
void signal_handler(int signal)
{
if (signal == SIGABRT) {
std::cerr << "Error processing input " << g_input_path << std::endl;
} else {
std::cerr << "Unexpected signal " << signal << " received\n";
}
std::_Exit(EXIT_FAILURE);
}
#endif
// This function is used by libFuzzer
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
static const auto& test_one_input = *Assert(g_test_one_input);
test_one_input({data, size});
return 0;
}
// This function is used by libFuzzer
extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv)
{
SetArgs(*argc, *argv);
initialize();
return 0;
}
#if defined(PROVIDE_FUZZ_MAIN_FUNCTION)
int main(int argc, char** argv)
{
initialize();
static const auto& test_one_input = *Assert(g_test_one_input);
#ifdef __AFL_LOOP
// Enable AFL persistent mode. Requires compilation using afl-clang-fast++.
// See fuzzing.md for details.
const uint8_t* buffer = __AFL_FUZZ_TESTCASE_BUF;
while (__AFL_LOOP(100000)) {
size_t buffer_len = __AFL_FUZZ_TESTCASE_LEN;
test_one_input({buffer, buffer_len});
}
#else
std::vector<uint8_t> buffer;
if (argc <= 1) {
if (!read_stdin(buffer)) {
return 0;
}
test_one_input(buffer);
return 0;
}
std::signal(SIGABRT, signal_handler);
const auto start_time{Now<SteadySeconds>()};
int tested = 0;
for (int i = 1; i < argc; ++i) {
fs::path input_path(*(argv + i));
if (fs::is_directory(input_path)) {
for (fs::directory_iterator it(input_path); it != fs::directory_iterator(); ++it) {
if (!fs::is_regular_file(it->path())) continue;
g_input_path = it->path();
Assert(read_file(it->path(), buffer));
test_one_input(buffer);
++tested;
buffer.clear();
}
} else {
g_input_path = input_path;
Assert(read_file(input_path, buffer));
test_one_input(buffer);
++tested;
buffer.clear();
}
}
const auto end_time{Now<SteadySeconds>()};
std::cout << g_fuzz_target << ": succeeded against " << tested << " files in " << count_seconds(end_time - start_time) << "s." << std::endl;
#endif
return 0;
}
#endif
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