Add default AFL frontend

bin/deepstate/frontend/afl.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python3.6
+# Copyright (c) 2019 Trail of Bits, Inc.
+#
+# 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.
+
+import os
+import sys
+import argparse
+
+from .frontend import DeepStateFrontend
+
+
+class AFL(DeepStateFrontend):
+  """ Defines default AFL fuzzer frontend """
+
+  @classmethod
+  def parse_args(cls):
+    parser = argparse.ArgumentParser(description="Use AFL as a back-end for DeepState.")
+
+    compile_group = parser.add_argument_group("compilation and instrumentation arguments")
+    compile_group.add_argument("--compile_test", type=str, help="Path to DeepState test harness for compilation.")
+    compile_group.add_argument("--compiler_args", default=[], nargs='+', help="Compiler flags (excluding -o) to pass to compiler.")
+    compile_group.add_argument("--out_test_name", type=str, default="out", help="Set name of generated instrumented binary.")
+
+    parser.add_argument("--dictionary", type=str, help="Optional fuzzer dictionary for AFL.")
+    parser.add_argument("--mem_limit", type=int, default=50, help="Child process memory limit in MB (default is 50).")
+    parser.add_argument("--file", type=str, help="Input file read by fuzzed program, if any.")
+
+    parser.add_argument("--dirty_mode", action='store_true', help="Fuzz without deterministic steps.")
+    parser.add_argument("--dumb_mode", action='store_true', help="Fuzz without instrumentation.")
+    parser.add_argument("--qemu_mode", action='store_true', help="Fuzz with QEMU mode.")
+    parser.add_argument("--crash_explore", action='store_true', help="Fuzz with crash exploration.")
+
+    cls.parser = parser
+    return super(AFL, cls).parse_args()
+
+
+  def compile(self):
+    args = self._args
+
+    lib_path = "/usr/local/lib/"
+    if not os.path.isfile(lib_path + "libdeepstate_AFL.a"):
+      raise RuntimeError("no AFL-instrumented DeepState static library found in {}".format(lib_path))
+
+    compiler_args = [args.compile_test, "-std=c++11"] + args.compiler_args + \
+                    ["-ldeepstate_AFL", "-o", args.out_test_name + ".afl"]
+    super().compile(compiler_args)
+
+
+def main():
+  fuzzer = AFL("afl-fuzz", compiler="afl-clang-fast++")
+  args = fuzzer.parse_args()
+
+  if args.fuzzer_help:
+    fuzzer.print_help()
+    sys.exit(0)
+
+  if args.compile_test:
+    print("COMPILING DEEPSTATE HARNESS FOR FUZZING...")
+    fuzzer.compile()
+    sys.exit(0)
+
+  if not args.seeds or not args.output_test_dir:
+    print("Error: --seeds and/or --output_test_dir required for fuzzing.")
+    sys.exit(1)
+
+  if not os.path.exists(args.seeds):
+    print("CREATING INPUT SEED DIRECTORY...")
+    os.mkdir(args.seeds)
+
+  if len([name for name in os.listdir(args.seeds)]) == 0:
+    print("Error: no seeds present in directory", args.seeds)
+    sys.exit(1)
+
+  cmd_dict = {
+    "-i": args.seeds,
+    "-o": args.output_test_dir,
+    "-t": str(args.timeout),
+    "-m": str(args.mem_limit)
+  }
+
+  # check if we are using one of AFL's many "modes"
+  if args.dirty_mode:
+    cmd_dict['-d'] = None
+  if args.dumb_mode:
+    cmd_dict['-n'] = None
+  if args.qemu_mode:
+    cmd_dict['-Q'] = None
+  if args.crash_explore:
+    cmd_dict['-C'] = None
+
+  # other misc arguments
+  if args.dictionary:
+    cmd_dict['-x'] = args.dictionary
+  if args.file:
+    cmd_dict['-f'] = args.file
+
+  cmd_dict['--'] = args.binary
+
+  # if not specified, set DeepState flags to help AFL coverage
+  if len(args.args) == 0:
+    args.args = ["--input_test_file", "@@", "--abort_on_fail", "--no_fork"]
+
+  fuzzer.cli_command(cmd_dict, cli_other=args.args)
+
+  print("EXECUTING FUZZER...")
+  fuzzer.execute_fuzzer()
+
+  return 0
+
+
+if __name__ == "__main__":
+  exit(main())