#!/usr/bin/env python # ################################################################ # Copyright (c) 2016-present, Facebook, Inc. # All rights reserved. # # This source code is licensed under both the BSD-style license (found in the # LICENSE file in the root directory of this source tree) and the GPLv2 (found # in the COPYING file in the root directory of this source tree). # ########################################################################## import argparse import contextlib import os import re import shlex import shutil import subprocess import sys import tempfile def abs_join(a, *p): return os.path.abspath(os.path.join(a, *p)) # Constants FUZZ_DIR = os.path.abspath(os.path.dirname(__file__)) CORPORA_DIR = abs_join(FUZZ_DIR, 'corpora') TARGETS = [ 'simple_round_trip', 'stream_round_trip', 'block_round_trip', 'simple_decompress', 'stream_decompress', 'block_decompress', ] ALL_TARGETS = TARGETS + ['all'] FUZZ_RNG_SEED_SIZE = 4 # Standard environment variables CC = os.environ.get('CC', 'cc') CXX = os.environ.get('CXX', 'c++') CPPFLAGS = os.environ.get('CPPFLAGS', '') CFLAGS = os.environ.get('CFLAGS', '-O3') CXXFLAGS = os.environ.get('CXXFLAGS', CFLAGS) LDFLAGS = os.environ.get('LDFLAGS', '') MFLAGS = os.environ.get('MFLAGS', '-j') # Fuzzing environment variables LIB_FUZZING_ENGINE = os.environ.get('LIB_FUZZING_ENGINE', 'libregression.a') AFL_FUZZ = os.environ.get('AFL_FUZZ', 'afl-fuzz') DECODECORPUS = os.environ.get('DECODECORPUS', abs_join(FUZZ_DIR, '..', 'decodecorpus')) # Sanitizer environment variables MSAN_EXTRA_CPPFLAGS = os.environ.get('MSAN_EXTRA_CPPFLAGS', '') MSAN_EXTRA_CFLAGS = os.environ.get('MSAN_EXTRA_CFLAGS', '') MSAN_EXTRA_CXXFLAGS = os.environ.get('MSAN_EXTRA_CXXFLAGS', '') MSAN_EXTRA_LDFLAGS = os.environ.get('MSAN_EXTRA_LDFLAGS', '') def create(r): d = os.path.abspath(r) if not os.path.isdir(d): os.mkdir(d) return d def check(r): d = os.path.abspath(r) if not os.path.isdir(d): return None return d @contextlib.contextmanager def tmpdir(): dirpath = tempfile.mkdtemp() try: yield dirpath finally: shutil.rmtree(dirpath, ignore_errors=True) def parse_targets(in_targets): targets = set() for target in in_targets: if not target: continue if target == 'all': targets = targets.union(TARGETS) elif target in TARGETS: targets.add(target) else: raise RuntimeError('{} is not a valid target'.format(target)) return list(targets) def targets_parser(args, description): parser = argparse.ArgumentParser(prog=args.pop(0), description=description) parser.add_argument( 'TARGET', nargs='*', type=str, help='Fuzz target(s) to build {{{}}}'.format(', '.join(ALL_TARGETS))) args, extra = parser.parse_known_args(args) args.extra = extra args.TARGET = parse_targets(args.TARGET) return args def parse_env_flags(args, flags): """ Look for flags set by environment variables. """ san_flags = ','.join(re.findall('-fsanitize=((?:[a-z]+,?)+)', flags)) nosan_flags = ','.join(re.findall('-fno-sanitize=((?:[a-z]+,?)+)', flags)) def set_sanitizer(sanitizer, default, san, nosan): if sanitizer in san and sanitizer in nosan: raise RuntimeError('-fno-sanitize={s} and -fsanitize={s} passed'. format(s=sanitizer)) if sanitizer in san: return True if sanitizer in nosan: return False return default san = set(san_flags.split(',')) nosan = set(nosan_flags.split(',')) args.asan = set_sanitizer('address', args.asan, san, nosan) args.msan = set_sanitizer('memory', args.msan, san, nosan) args.ubsan = set_sanitizer('undefined', args.ubsan, san, nosan) args.sanitize = args.asan or args.msan or args.ubsan return args def compiler_version(cc, cxx): """ Determines the compiler and version. Only works for clang and gcc. """ cc_version_bytes = subprocess.check_output([cc, "--version"]) cxx_version_bytes = subprocess.check_output([cxx, "--version"]) compiler = None version = None if b'clang' in cc_version_bytes: assert(b'clang' in cxx_version_bytes) compiler = 'clang' elif b'gcc' in cc_version_bytes: assert(b'gcc' in cxx_version_bytes) compiler = 'gcc' if compiler is not None: version_regex = b'([0-9])+\.([0-9])+\.([0-9])+' version_match = re.search(version_regex, cc_version_bytes) version = tuple(int(version_match.group(i)) for i in range(1, 4)) return compiler, version def overflow_ubsan_flags(cc, cxx): compiler, version = compiler_version(cc, cxx) if compiler == 'gcc': return ['-fno-sanitize=signed-integer-overflow'] if compiler == 'clang' and version >= (5, 0, 0): return ['-fno-sanitize=pointer-overflow'] return [] def build_parser(args): description = """ Cleans the repository and builds a fuzz target (or all). Many flags default to environment variables (default says $X='y'). Options that aren't enabling features default to the correct values for zstd. Enable sanitizers with --enable-*san. For regression testing just build. For libFuzzer set LIB_FUZZING_ENGINE and pass --enable-coverage. For AFL set CC and CXX to AFL's compilers and set LIB_FUZZING_ENGINE='libregression.a'. """ parser = argparse.ArgumentParser(prog=args.pop(0), description=description) parser.add_argument( '--lib-fuzzing-engine', dest='lib_fuzzing_engine', type=str, default=LIB_FUZZING_ENGINE, help=('The fuzzing engine to use e.g. /path/to/libFuzzer.a ' "(default: $LIB_FUZZING_ENGINE='{})".format(LIB_FUZZING_ENGINE))) fuzz_group = parser.add_mutually_exclusive_group() fuzz_group.add_argument( '--enable-coverage', dest='coverage', action='store_true', help='Enable coverage instrumentation (-fsanitize-coverage)') fuzz_group.add_argument( '--enable-fuzzer', dest='fuzzer', action='store_true', help=('Enable clang fuzzer (-fsanitize=fuzzer). When enabled ' 'LIB_FUZZING_ENGINE is ignored') ) parser.add_argument( '--enable-asan', dest='asan', action='store_true', help='Enable UBSAN') parser.add_argument( '--enable-ubsan', dest='ubsan', action='store_true', help='Enable UBSAN') parser.add_argument( '--enable-ubsan-pointer-overflow', dest='ubsan_pointer_overflow', action='store_true', help='Enable UBSAN pointer overflow check (known failure)') parser.add_argument( '--enable-msan', dest='msan', action='store_true', help='Enable MSAN') parser.add_argument( '--enable-msan-track-origins', dest='msan_track_origins', action='store_true', help='Enable MSAN origin tracking') parser.add_argument( '--msan-extra-cppflags', dest='msan_extra_cppflags', type=str, default=MSAN_EXTRA_CPPFLAGS, help="Extra CPPFLAGS for MSAN (default: $MSAN_EXTRA_CPPFLAGS='{}')". format(MSAN_EXTRA_CPPFLAGS)) parser.add_argument( '--msan-extra-cflags', dest='msan_extra_cflags', type=str, default=MSAN_EXTRA_CFLAGS, help="Extra CFLAGS for MSAN (default: $MSAN_EXTRA_CFLAGS='{}')".format( MSAN_EXTRA_CFLAGS)) parser.add_argument( '--msan-extra-cxxflags', dest='msan_extra_cxxflags', type=str, default=MSAN_EXTRA_CXXFLAGS, help="Extra CXXFLAGS for MSAN (default: $MSAN_EXTRA_CXXFLAGS='{}')". format(MSAN_EXTRA_CXXFLAGS)) parser.add_argument( '--msan-extra-ldflags', dest='msan_extra_ldflags', type=str, default=MSAN_EXTRA_LDFLAGS, help="Extra LDFLAGS for MSAN (default: $MSAN_EXTRA_LDFLAGS='{}')". format(MSAN_EXTRA_LDFLAGS)) parser.add_argument( '--enable-sanitize-recover', dest='sanitize_recover', action='store_true', help='Non-fatal sanitizer errors where possible') parser.add_argument( '--debug', dest='debug', type=int, default=1, help='Set DEBUGLEVEL (default: 1)') parser.add_argument( '--force-memory-access', dest='memory_access', type=int, default=0, help='Set MEM_FORCE_MEMORY_ACCESS (default: 0)') parser.add_argument( '--fuzz-rng-seed-size', dest='fuzz_rng_seed_size', type=int, default=4, help='Set FUZZ_RNG_SEED_SIZE (default: 4)') parser.add_argument( '--disable-fuzzing-mode', dest='fuzzing_mode', action='store_false', help='Do not define FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION') parser.add_argument( '--enable-stateful-fuzzing', dest='stateful_fuzzing', action='store_true', help='Reuse contexts between runs (makes reproduction impossible)') parser.add_argument( '--cc', dest='cc', type=str, default=CC, help="CC (default: $CC='{}')".format(CC)) parser.add_argument( '--cxx', dest='cxx', type=str, default=CXX, help="CXX (default: $CXX='{}')".format(CXX)) parser.add_argument( '--cppflags', dest='cppflags', type=str, default=CPPFLAGS, help="CPPFLAGS (default: $CPPFLAGS='{}')".format(CPPFLAGS)) parser.add_argument( '--cflags', dest='cflags', type=str, default=CFLAGS, help="CFLAGS (default: $CFLAGS='{}')".format(CFLAGS)) parser.add_argument( '--cxxflags', dest='cxxflags', type=str, default=CXXFLAGS, help="CXXFLAGS (default: $CXXFLAGS='{}')".format(CXXFLAGS)) parser.add_argument( '--ldflags', dest='ldflags', type=str, default=LDFLAGS, help="LDFLAGS (default: $LDFLAGS='{}')".format(LDFLAGS)) parser.add_argument( '--mflags', dest='mflags', type=str, default=MFLAGS, help="Extra Make flags (default: $MFLAGS='{}')".format(MFLAGS)) parser.add_argument( 'TARGET', nargs='*', type=str, help='Fuzz target(s) to build {{{}}}'.format(', '.join(ALL_TARGETS)) ) args = parser.parse_args(args) args = parse_env_flags(args, ' '.join( [args.cppflags, args.cflags, args.cxxflags, args.ldflags])) # Check option sanitiy if args.msan and (args.asan or args.ubsan): raise RuntimeError('MSAN may not be used with any other sanitizers') if args.msan_track_origins and not args.msan: raise RuntimeError('--enable-msan-track-origins requires MSAN') if args.ubsan_pointer_overflow and not args.ubsan: raise RuntimeError('--enable-ubsan-pointer-overlow requires UBSAN') if args.sanitize_recover and not args.sanitize: raise RuntimeError('--enable-sanitize-recover but no sanitizers used') return args def build(args): try: args = build_parser(args) except Exception as e: print(e) return 1 # The compilation flags we are setting targets = args.TARGET cc = args.cc cxx = args.cxx cppflags = shlex.split(args.cppflags) cflags = shlex.split(args.cflags) ldflags = shlex.split(args.ldflags) cxxflags = shlex.split(args.cxxflags) mflags = shlex.split(args.mflags) # Flags to be added to both cflags and cxxflags common_flags = [] cppflags += [ '-DDEBUGLEVEL={}'.format(args.debug), '-DMEM_FORCE_MEMORY_ACCESS={}'.format(args.memory_access), '-DFUZZ_RNG_SEED_SIZE={}'.format(args.fuzz_rng_seed_size), ] # Set flags for options assert not (args.fuzzer and args.coverage) if args.coverage: common_flags += [ '-fsanitize-coverage=trace-pc-guard,indirect-calls,trace-cmp' ] if args.fuzzer: common_flags += ['-fsanitize=fuzzer'] args.lib_fuzzing_engine = '' mflags += ['LIB_FUZZING_ENGINE={}'.format(args.lib_fuzzing_engine)] if args.sanitize_recover: recover_flags = ['-fsanitize-recover=all'] else: recover_flags = ['-fno-sanitize-recover=all'] if args.sanitize: common_flags += recover_flags if args.msan: msan_flags = ['-fsanitize=memory'] if args.msan_track_origins: msan_flags += ['-fsanitize-memory-track-origins'] common_flags += msan_flags # Append extra MSAN flags (it might require special setup) cppflags += [args.msan_extra_cppflags] cflags += [args.msan_extra_cflags] cxxflags += [args.msan_extra_cxxflags] ldflags += [args.msan_extra_ldflags] if args.asan: common_flags += ['-fsanitize=address'] if args.ubsan: ubsan_flags = ['-fsanitize=undefined'] if not args.ubsan_pointer_overflow: ubsan_flags += overflow_ubsan_flags(cc, cxx) common_flags += ubsan_flags if args.stateful_fuzzing: cppflags += ['-DSTATEFUL_FUZZING'] if args.fuzzing_mode: cppflags += ['-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION'] if args.lib_fuzzing_engine == 'libregression.a': targets = ['libregression.a'] + targets # Append the common flags cflags += common_flags cxxflags += common_flags # Prepare the flags for Make cc_str = "CC={}".format(cc) cxx_str = "CXX={}".format(cxx) cppflags_str = "CPPFLAGS={}".format(' '.join(cppflags)) cflags_str = "CFLAGS={}".format(' '.join(cflags)) cxxflags_str = "CXXFLAGS={}".format(' '.join(cxxflags)) ldflags_str = "LDFLAGS={}".format(' '.join(ldflags)) # Print the flags print('MFLAGS={}'.format(' '.join(mflags))) print(cc_str) print(cxx_str) print(cppflags_str) print(cflags_str) print(cxxflags_str) print(ldflags_str) # Clean and build clean_cmd = ['make', 'clean'] + mflags print(' '.join(clean_cmd)) subprocess.check_call(clean_cmd) build_cmd = [ 'make', cc_str, cxx_str, cppflags_str, cflags_str, cxxflags_str, ldflags_str, ] + mflags + targets print(' '.join(build_cmd)) subprocess.check_call(build_cmd) return 0 def libfuzzer_parser(args): description = """ Runs a libfuzzer binary. Passes all extra arguments to libfuzzer. The fuzzer should have been build with LIB_FUZZING_ENGINE pointing to libFuzzer.a. Generates output in the CORPORA directory, puts crashes in the ARTIFACT directory, and takes extra input from the SEED directory. To merge AFL's output pass the SEED as AFL's output directory and pass '-merge=1'. """ parser = argparse.ArgumentParser(prog=args.pop(0), description=description) parser.add_argument( '--corpora', type=str, help='Override the default corpora dir (default: {})'.format( abs_join(CORPORA_DIR, 'TARGET'))) parser.add_argument( '--artifact', type=str, help='Override the default artifact dir (default: {})'.format( abs_join(CORPORA_DIR, 'TARGET-crash'))) parser.add_argument( '--seed', type=str, help='Override the default seed dir (default: {})'.format( abs_join(CORPORA_DIR, 'TARGET-seed'))) parser.add_argument( 'TARGET', type=str, help='Fuzz target(s) to build {{{}}}'.format(', '.join(TARGETS))) args, extra = parser.parse_known_args(args) args.extra = extra if args.TARGET and args.TARGET not in TARGETS: raise RuntimeError('{} is not a valid target'.format(args.TARGET)) return args def libfuzzer(target, corpora=None, artifact=None, seed=None, extra_args=None): if corpora is None: corpora = abs_join(CORPORA_DIR, target) if artifact is None: artifact = abs_join(CORPORA_DIR, '{}-crash'.format(target)) if seed is None: seed = abs_join(CORPORA_DIR, '{}-seed'.format(target)) if extra_args is None: extra_args = [] target = abs_join(FUZZ_DIR, target) corpora = [create(corpora)] artifact = create(artifact) seed = check(seed) corpora += [artifact] if seed is not None: corpora += [seed] cmd = [target, '-artifact_prefix={}/'.format(artifact)] cmd += corpora + extra_args print(' '.join(cmd)) subprocess.check_call(cmd) def libfuzzer_cmd(args): try: args = libfuzzer_parser(args) except Exception as e: print(e) return 1 libfuzzer(args.TARGET, args.corpora, args.artifact, args.seed, args.extra) return 0 def afl_parser(args): description = """ Runs an afl-fuzz job. Passes all extra arguments to afl-fuzz. The fuzzer should have been built with CC/CXX set to the AFL compilers, and with LIB_FUZZING_ENGINE='libregression.a'. Takes input from CORPORA and writes output to OUTPUT. Uses AFL_FUZZ as the binary (set from flag or environment variable). """ parser = argparse.ArgumentParser(prog=args.pop(0), description=description) parser.add_argument( '--corpora', type=str, help='Override the default corpora dir (default: {})'.format( abs_join(CORPORA_DIR, 'TARGET'))) parser.add_argument( '--output', type=str, help='Override the default AFL output dir (default: {})'.format( abs_join(CORPORA_DIR, 'TARGET-afl'))) parser.add_argument( '--afl-fuzz', type=str, default=AFL_FUZZ, help='AFL_FUZZ (default: $AFL_FUZZ={})'.format(AFL_FUZZ)) parser.add_argument( 'TARGET', type=str, help='Fuzz target(s) to build {{{}}}'.format(', '.join(TARGETS))) args, extra = parser.parse_known_args(args) args.extra = extra if args.TARGET and args.TARGET not in TARGETS: raise RuntimeError('{} is not a valid target'.format(args.TARGET)) if not args.corpora: args.corpora = abs_join(CORPORA_DIR, args.TARGET) if not args.output: args.output = abs_join(CORPORA_DIR, '{}-afl'.format(args.TARGET)) return args def afl(args): try: args = afl_parser(args) except Exception as e: print(e) return 1 target = abs_join(FUZZ_DIR, args.TARGET) corpora = create(args.corpora) output = create(args.output) cmd = [args.afl_fuzz, '-i', corpora, '-o', output] + args.extra cmd += [target, '@@'] print(' '.join(cmd)) subprocess.call(cmd) return 0 def regression(args): try: description = """ Runs one or more regression tests. The fuzzer should have been built with with LIB_FUZZING_ENGINE='libregression.a'. Takes input from CORPORA. """ args = targets_parser(args, description) except Exception as e: print(e) return 1 for target in args.TARGET: corpora = create(abs_join(CORPORA_DIR, target)) target = abs_join(FUZZ_DIR, target) cmd = [target, corpora] print(' '.join(cmd)) subprocess.check_call(cmd) return 0 def gen_parser(args): description = """ Generate a seed corpus appropiate for TARGET with data generated with decodecorpus. The fuzz inputs are prepended with a seed before the zstd data, so the output of decodecorpus shouldn't be used directly. Generates NUMBER samples prepended with FUZZ_RNG_SEED_SIZE random bytes and puts the output in SEED. DECODECORPUS is the decodecorpus binary, and must already be built. """ parser = argparse.ArgumentParser(prog=args.pop(0), description=description) parser.add_argument( '--number', '-n', type=int, default=100, help='Number of samples to generate') parser.add_argument( '--max-size-log', type=int, default=13, help='Maximum sample size to generate') parser.add_argument( '--seed', type=str, help='Override the default seed dir (default: {})'.format( abs_join(CORPORA_DIR, 'TARGET-seed'))) parser.add_argument( '--decodecorpus', type=str, default=DECODECORPUS, help="decodecorpus binary (default: $DECODECORPUS='{}')".format( DECODECORPUS)) parser.add_argument( '--fuzz-rng-seed-size', type=int, default=4, help="FUZZ_RNG_SEED_SIZE used for generate the samples (must match)" ) parser.add_argument( 'TARGET', type=str, help='Fuzz target(s) to build {{{}}}'.format(', '.join(TARGETS))) args, extra = parser.parse_known_args(args) args.extra = extra if args.TARGET and args.TARGET not in TARGETS: raise RuntimeError('{} is not a valid target'.format(args.TARGET)) if not args.seed: args.seed = abs_join(CORPORA_DIR, '{}-seed'.format(args.TARGET)) if not os.path.isfile(args.decodecorpus): raise RuntimeError("{} is not a file run 'make -C {} decodecorpus'". format(args.decodecorpus, abs_join(FUZZ_DIR, '..'))) return args def gen(args): try: args = gen_parser(args) except Exception as e: print(e) return 1 seed = create(args.seed) with tmpdir() as compressed: with tmpdir() as decompressed: cmd = [ args.decodecorpus, '-n{}'.format(args.number), '-p{}/'.format(compressed), '-o{}'.format(decompressed), ] if 'block_' in args.TARGET: cmd += [ '--gen-blocks', '--max-block-size-log={}'.format(args.max_size_log) ] else: cmd += ['--max-content-size-log={}'.format(args.max_size_log)] print(' '.join(cmd)) subprocess.check_call(cmd) if '_round_trip' in args.TARGET: print('using decompressed data in {}'.format(decompressed)) samples = decompressed elif '_decompress' in args.TARGET: print('using compressed data in {}'.format(compressed)) samples = compressed # Copy the samples over and prepend the RNG seeds for name in os.listdir(samples): samplename = abs_join(samples, name) outname = abs_join(seed, name) rng_seed = os.urandom(args.fuzz_rng_seed_size) with open(samplename, 'rb') as sample: with open(outname, 'wb') as out: out.write(rng_seed) CHUNK_SIZE = 131072 chunk = sample.read(CHUNK_SIZE) while len(chunk) > 0: out.write(chunk) chunk = sample.read(CHUNK_SIZE) return 0 def minimize(args): try: description = """ Runs a libfuzzer fuzzer with -merge=1 to build a minimal corpus in TARGET_seed_corpus. All extra args are passed to libfuzzer. """ args = targets_parser(args, description) except Exception as e: print(e) return 1 for target in args.TARGET: # Merge the corpus + anything else into the seed_corpus corpus = abs_join(CORPORA_DIR, target) seed_corpus = abs_join(CORPORA_DIR, "{}_seed_corpus".format(target)) extra_args = [corpus, "-merge=1"] + args.extra libfuzzer(target, corpora=seed_corpus, extra_args=extra_args) seeds = set(os.listdir(seed_corpus)) # Copy all crashes directly into the seed_corpus if not already present crashes = abs_join(CORPORA_DIR, '{}-crash'.format(target)) for crash in os.listdir(crashes): if crash not in seeds: shutil.copy(abs_join(crashes, crash), seed_corpus) seeds.add(crash) def zip_cmd(args): try: description = """ Zips up the seed corpus. """ args = targets_parser(args, description) except Exception as e: print(e) return 1 for target in args.TARGET: # Zip the seed_corpus seed_corpus = abs_join(CORPORA_DIR, "{}_seed_corpus".format(target)) zip_file = "{}.zip".format(seed_corpus) cmd = ["zip", "-r", "-q", "-j", "-9", zip_file, "."] print(' '.join(cmd)) subprocess.check_call(cmd, cwd=seed_corpus) def list_cmd(args): print("\n".join(TARGETS)) def short_help(args): name = args[0] print("Usage: {} [OPTIONS] COMMAND [ARGS]...\n".format(name)) def help(args): short_help(args) print("\tfuzzing helpers (select a command and pass -h for help)\n") print("Options:") print("\t-h, --help\tPrint this message") print("") print("Commands:") print("\tbuild\t\tBuild a fuzzer") print("\tlibfuzzer\tRun a libFuzzer fuzzer") print("\tafl\t\tRun an AFL fuzzer") print("\tregression\tRun a regression test") print("\tgen\t\tGenerate a seed corpus for a fuzzer") print("\tminimize\tMinimize the test corpora") print("\tzip\t\tZip the minimized corpora up") print("\tlist\t\tList the available targets") def main(): args = sys.argv if len(args) < 2: help(args) return 1 if args[1] == '-h' or args[1] == '--help' or args[1] == '-H': help(args) return 1 command = args.pop(1) args[0] = "{} {}".format(args[0], command) if command == "build": return build(args) if command == "libfuzzer": return libfuzzer_cmd(args) if command == "regression": return regression(args) if command == "afl": return afl(args) if command == "gen": return gen(args) if command == "minimize": return minimize(args) if command == "zip": return zip_cmd(args) if command == "list": return list_cmd(args) short_help(args) print("Error: No such command {} (pass -h for help)".format(command)) return 1 if __name__ == "__main__": sys.exit(main())