diff options
Diffstat (limited to 'lib/Fuzzer/afl/afl_driver.cpp')
| -rw-r--r-- | lib/Fuzzer/afl/afl_driver.cpp | 335 |
1 files changed, 0 insertions, 335 deletions
diff --git a/lib/Fuzzer/afl/afl_driver.cpp b/lib/Fuzzer/afl/afl_driver.cpp deleted file mode 100644 index 15bceb896e17..000000000000 --- a/lib/Fuzzer/afl/afl_driver.cpp +++ /dev/null @@ -1,335 +0,0 @@ -//===- afl_driver.cpp - a glue between AFL and libFuzzer --------*- C++ -* ===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -//===----------------------------------------------------------------------===// - -/* This file allows to fuzz libFuzzer-style target functions - (LLVMFuzzerTestOneInput) with AFL using AFL's persistent (in-process) mode. - -Usage: -################################################################################ -cat << EOF > test_fuzzer.cc -#include <stddef.h> -#include <stdint.h> -extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { - if (size > 0 && data[0] == 'H') - if (size > 1 && data[1] == 'I') - if (size > 2 && data[2] == '!') - __builtin_trap(); - return 0; -} -EOF -# Build your target with -fsanitize-coverage=trace-pc-guard using fresh clang. -clang -g -fsanitize-coverage=trace-pc-guard test_fuzzer.cc -c -# Build afl-llvm-rt.o.c from the AFL distribution. -clang -c -w $AFL_HOME/llvm_mode/afl-llvm-rt.o.c -# Build this file, link it with afl-llvm-rt.o.o and the target code. -clang++ afl_driver.cpp test_fuzzer.o afl-llvm-rt.o.o -# Run AFL: -rm -rf IN OUT; mkdir IN OUT; echo z > IN/z; -$AFL_HOME/afl-fuzz -i IN -o OUT ./a.out -################################################################################ -Environment Variables: -There are a few environment variables that can be set to use features that -afl-fuzz doesn't have. - -AFL_DRIVER_STDERR_DUPLICATE_FILENAME: Setting this *appends* stderr to the file -specified. If the file does not exist, it is created. This is useful for getting -stack traces (when using ASAN for example) or original error messages on hard to -reproduce bugs. - -AFL_DRIVER_EXTRA_STATS_FILENAME: Setting this causes afl_driver to write extra -statistics to the file specified. Currently these are peak_rss_mb -(the peak amount of virtual memory used in MB) and slowest_unit_time_secs. If -the file does not exist it is created. If the file does exist then -afl_driver assumes it was restarted by afl-fuzz and will try to read old -statistics from the file. If that fails then the process will quit. - -*/ -#include <assert.h> -#include <errno.h> -#include <signal.h> -#include <stdint.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <sys/resource.h> -#include <sys/time.h> -#include <unistd.h> - -#include <fstream> -#include <iostream> -#include <vector> - -// Platform detection. Copied from FuzzerInternal.h -#ifdef __linux__ -#define LIBFUZZER_LINUX 1 -#define LIBFUZZER_APPLE 0 -#elif __APPLE__ -#define LIBFUZZER_LINUX 0 -#define LIBFUZZER_APPLE 1 -#else -#error "Support for your platform has not been implemented" -#endif - -// Used to avoid repeating error checking boilerplate. If cond is false, a -// fatal error has occured in the program. In this event print error_message -// to stderr and abort(). Otherwise do nothing. Note that setting -// AFL_DRIVER_STDERR_DUPLICATE_FILENAME may cause error_message to be appended -// to the file as well, if the error occurs after the duplication is performed. -#define CHECK_ERROR(cond, error_message) \ - if (!(cond)) { \ - fprintf(stderr, (error_message)); \ - abort(); \ - } - -// libFuzzer interface is thin, so we don't include any libFuzzer headers. -extern "C" { -int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size); -__attribute__((weak)) int LLVMFuzzerInitialize(int *argc, char ***argv); -} - -// Notify AFL about persistent mode. -static volatile char AFL_PERSISTENT[] = "##SIG_AFL_PERSISTENT##"; -extern "C" int __afl_persistent_loop(unsigned int); -static volatile char suppress_warning2 = AFL_PERSISTENT[0]; - -// Notify AFL about deferred forkserver. -static volatile char AFL_DEFER_FORKSVR[] = "##SIG_AFL_DEFER_FORKSRV##"; -extern "C" void __afl_manual_init(); -static volatile char suppress_warning1 = AFL_DEFER_FORKSVR[0]; - -// Input buffer. -static const size_t kMaxAflInputSize = 1 << 20; -static uint8_t AflInputBuf[kMaxAflInputSize]; - -// Variables we need for writing to the extra stats file. -static FILE *extra_stats_file = NULL; -static uint32_t previous_peak_rss = 0; -static time_t slowest_unit_time_secs = 0; -static const int kNumExtraStats = 2; -static const char *kExtraStatsFormatString = "peak_rss_mb : %u\n" - "slowest_unit_time_sec : %u\n"; - -// Copied from FuzzerUtil.cpp. -size_t GetPeakRSSMb() { - struct rusage usage; - if (getrusage(RUSAGE_SELF, &usage)) - return 0; - if (LIBFUZZER_LINUX) { - // ru_maxrss is in KiB - return usage.ru_maxrss >> 10; - } else if (LIBFUZZER_APPLE) { - // ru_maxrss is in bytes - return usage.ru_maxrss >> 20; - } - assert(0 && "GetPeakRSSMb() is not implemented for your platform"); - return 0; -} - -// Based on SetSigaction in FuzzerUtil.cpp -static void SetSigaction(int signum, - void (*callback)(int, siginfo_t *, void *)) { - struct sigaction sigact; - memset(&sigact, 0, sizeof(sigact)); - sigact.sa_sigaction = callback; - if (sigaction(signum, &sigact, 0)) { - fprintf(stderr, "libFuzzer: sigaction failed with %d\n", errno); - exit(1); - } -} - -// Write extra stats to the file specified by the user. If none is specified -// this function will never be called. -static void write_extra_stats() { - uint32_t peak_rss = GetPeakRSSMb(); - - if (peak_rss < previous_peak_rss) - peak_rss = previous_peak_rss; - - int chars_printed = fprintf(extra_stats_file, kExtraStatsFormatString, - peak_rss, slowest_unit_time_secs); - - CHECK_ERROR(chars_printed != 0, "Failed to write extra_stats_file"); - - CHECK_ERROR(fclose(extra_stats_file) == 0, - "Failed to close extra_stats_file"); -} - -// Call write_extra_stats before we exit. -static void crash_handler(int, siginfo_t *, void *) { - // Make sure we don't try calling write_extra_stats again if we crashed while - // trying to call it. - static bool first_crash = true; - CHECK_ERROR(first_crash, - "Crashed in crash signal handler. This is a bug in the fuzzer."); - - first_crash = false; - write_extra_stats(); -} - -// If the user has specified an extra_stats_file through the environment -// variable AFL_DRIVER_EXTRA_STATS_FILENAME, then perform necessary set up -// to write stats to it on exit. If no file is specified, do nothing. Otherwise -// install signal and exit handlers to write to the file when the process exits. -// Then if the file doesn't exist create it and set extra stats to 0. But if it -// does exist then read the initial values of the extra stats from the file -// and check that the file is writable. -static void maybe_initialize_extra_stats() { - // If AFL_DRIVER_EXTRA_STATS_FILENAME isn't set then we have nothing to do. - char *extra_stats_filename = getenv("AFL_DRIVER_EXTRA_STATS_FILENAME"); - if (!extra_stats_filename) - return; - - // Open the file and find the previous peak_rss_mb value. - // This is necessary because the fuzzing process is restarted after N - // iterations are completed. So we may need to get this value from a previous - // process to be accurate. - extra_stats_file = fopen(extra_stats_filename, "r"); - - // If extra_stats_file already exists: read old stats from it. - if (extra_stats_file) { - int matches = fscanf(extra_stats_file, kExtraStatsFormatString, - &previous_peak_rss, &slowest_unit_time_secs); - - // Make sure we have read a real extra stats file and that we have used it - // to set slowest_unit_time_secs and previous_peak_rss. - CHECK_ERROR(matches == kNumExtraStats, "Extra stats file is corrupt"); - - CHECK_ERROR(fclose(extra_stats_file) == 0, "Failed to close file"); - - // Now open the file for writing. - extra_stats_file = fopen(extra_stats_filename, "w"); - CHECK_ERROR(extra_stats_file, - "Failed to open extra stats file for writing"); - } else { - // Looks like this is the first time in a fuzzing job this is being called. - extra_stats_file = fopen(extra_stats_filename, "w+"); - CHECK_ERROR(extra_stats_file, "failed to create extra stats file"); - } - - // Make sure that crash_handler gets called on any kind of fatal error. - int crash_signals[] = {SIGSEGV, SIGBUS, SIGABRT, SIGILL, SIGFPE, SIGINT, - SIGTERM}; - - const size_t num_signals = sizeof(crash_signals) / sizeof(crash_signals[0]); - - for (size_t idx = 0; idx < num_signals; idx++) - SetSigaction(crash_signals[idx], crash_handler); - - // Make sure it gets called on other kinds of exits. - atexit(write_extra_stats); -} - -// If the user asks us to duplicate stderr, then do it. -static void maybe_duplicate_stderr() { - char* stderr_duplicate_filename = - getenv("AFL_DRIVER_STDERR_DUPLICATE_FILENAME"); - - if (!stderr_duplicate_filename) - return; - - FILE* stderr_duplicate_stream = - freopen(stderr_duplicate_filename, "a+", stderr); - - if (!stderr_duplicate_stream) { - fprintf( - stderr, - "Failed to duplicate stderr to AFL_DRIVER_STDERR_DUPLICATE_FILENAME"); - abort(); - } -} - -// Define LLVMFuzzerMutate to avoid link failures for targets that use it -// with libFuzzer's LLVMFuzzerCustomMutator. -extern "C" size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) { - assert(false && "LLVMFuzzerMutate should not be called from afl_driver"); - return 0; -} - -// Execute any files provided as parameters. -int ExecuteFilesOnyByOne(int argc, char **argv) { - for (int i = 1; i < argc; i++) { - std::ifstream in(argv[i]); - in.seekg(0, in.end); - size_t length = in.tellg(); - in.seekg (0, in.beg); - std::cout << "Reading " << length << " bytes from " << argv[i] << std::endl; - // Allocate exactly length bytes so that we reliably catch buffer overflows. - std::vector<char> bytes(length); - in.read(bytes.data(), bytes.size()); - assert(in); - LLVMFuzzerTestOneInput(reinterpret_cast<const uint8_t *>(bytes.data()), - bytes.size()); - std::cout << "Execution successfull" << std::endl; - } - return 0; -} - -int main(int argc, char **argv) { - fprintf(stderr, - "======================= INFO =========================\n" - "This binary is built for AFL-fuzz.\n" - "To run the target function on individual input(s) execute this:\n" - " %s < INPUT_FILE\n" - "or\n" - " %s INPUT_FILE1 [INPUT_FILE2 ... ]\n" - "To fuzz with afl-fuzz execute this:\n" - " afl-fuzz [afl-flags] %s [-N]\n" - "afl-fuzz will run N iterations before " - "re-spawning the process (default: 1000)\n" - "======================================================\n", - argv[0], argv[0], argv[0]); - if (LLVMFuzzerInitialize) - LLVMFuzzerInitialize(&argc, &argv); - // Do any other expensive one-time initialization here. - - maybe_duplicate_stderr(); - maybe_initialize_extra_stats(); - - __afl_manual_init(); - - int N = 1000; - if (argc == 2 && argv[1][0] == '-') - N = atoi(argv[1] + 1); - else if(argc == 2 && (N = atoi(argv[1])) > 0) - fprintf(stderr, "WARNING: using the deprecated call style `%s %d`\n", - argv[0], N); - else if (argc > 1) - return ExecuteFilesOnyByOne(argc, argv); - - assert(N > 0); - time_t unit_time_secs; - int num_runs = 0; - while (__afl_persistent_loop(N)) { - ssize_t n_read = read(0, AflInputBuf, kMaxAflInputSize); - if (n_read > 0) { - // Copy AflInputBuf into a separate buffer to let asan find buffer - // overflows. Don't use unique_ptr/etc to avoid extra dependencies. - uint8_t *copy = new uint8_t[n_read]; - memcpy(copy, AflInputBuf, n_read); - - struct timeval unit_start_time; - CHECK_ERROR(gettimeofday(&unit_start_time, NULL) == 0, - "Calling gettimeofday failed"); - - num_runs++; - LLVMFuzzerTestOneInput(copy, n_read); - - struct timeval unit_stop_time; - CHECK_ERROR(gettimeofday(&unit_stop_time, NULL) == 0, - "Calling gettimeofday failed"); - - // Update slowest_unit_time_secs if we see a new max. - unit_time_secs = unit_stop_time.tv_sec - unit_start_time.tv_sec; - if (slowest_unit_time_secs < unit_time_secs) - slowest_unit_time_secs = unit_time_secs; - - delete[] copy; - } - } - fprintf(stderr, "%s: successfully executed %d input(s)\n", argv[0], num_runs); -} |