1#!/usr/bin/env python 2 3# Tool for running fuzz tests 4# 5# Copyright (C) 2014 Maria Kustova <maria.k@catit.be> 6# 7# This program is free software: you can redistribute it and/or modify 8# it under the terms of the GNU General Public License as published by 9# the Free Software Foundation, either version 2 of the License, or 10# (at your option) any later version. 11# 12# This program is distributed in the hope that it will be useful, 13# but WITHOUT ANY WARRANTY; without even the implied warranty of 14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15# GNU General Public License for more details. 16# 17# You should have received a copy of the GNU General Public License 18# along with this program. If not, see <http://www.gnu.org/licenses/>. 19# 20 21import sys 22import os 23import signal 24import subprocess 25import random 26import shutil 27from itertools import count 28import time 29import getopt 30import StringIO 31import resource 32 33try: 34 import json 35except ImportError: 36 try: 37 import simplejson as json 38 except ImportError: 39 print >>sys.stderr, \ 40 "Warning: Module for JSON processing is not found.\n" \ 41 "'--config' and '--command' options are not supported." 42 43# Backing file sizes in MB 44MAX_BACKING_FILE_SIZE = 10 45MIN_BACKING_FILE_SIZE = 1 46 47 48def multilog(msg, *output): 49 """ Write an object to all of specified file descriptors.""" 50 for fd in output: 51 fd.write(msg) 52 fd.flush() 53 54 55def str_signal(sig): 56 """ Convert a numeric value of a system signal to the string one 57 defined by the current operational system. 58 """ 59 for k, v in signal.__dict__.items(): 60 if v == sig: 61 return k 62 63 64def run_app(fd, q_args): 65 """Start an application with specified arguments and return its exit code 66 or kill signal depending on the result of execution. 67 """ 68 69 class Alarm(Exception): 70 """Exception for signal.alarm events.""" 71 pass 72 73 def handler(*args): 74 """Notify that an alarm event occurred.""" 75 raise Alarm 76 77 signal.signal(signal.SIGALRM, handler) 78 signal.alarm(600) 79 term_signal = signal.SIGKILL 80 devnull = open('/dev/null', 'r+') 81 process = subprocess.Popen(q_args, stdin=devnull, 82 stdout=subprocess.PIPE, 83 stderr=subprocess.PIPE) 84 try: 85 out, err = process.communicate() 86 signal.alarm(0) 87 fd.write(out) 88 fd.write(err) 89 fd.flush() 90 return process.returncode 91 92 except Alarm: 93 os.kill(process.pid, term_signal) 94 fd.write('The command was terminated by timeout.\n') 95 fd.flush() 96 return -term_signal 97 98 99class TestException(Exception): 100 """Exception for errors risen by TestEnv objects.""" 101 pass 102 103 104class TestEnv(object): 105 106 """Test object. 107 108 The class sets up test environment, generates backing and test images 109 and executes application under tests with specified arguments and a test 110 image provided. 111 112 All logs are collected. 113 114 The summary log will contain short descriptions and statuses of tests in 115 a run. 116 117 The test log will include application (e.g. 'qemu-img') logs besides info 118 sent to the summary log. 119 """ 120 121 def __init__(self, test_id, seed, work_dir, run_log, 122 cleanup=True, log_all=False): 123 """Set test environment in a specified work directory. 124 125 Path to qemu-img and qemu-io will be retrieved from 'QEMU_IMG' and 126 'QEMU_IO' environment variables. 127 """ 128 if seed is not None: 129 self.seed = seed 130 else: 131 self.seed = str(random.randint(0, sys.maxint)) 132 random.seed(self.seed) 133 134 self.init_path = os.getcwd() 135 self.work_dir = work_dir 136 self.current_dir = os.path.join(work_dir, 'test-' + test_id) 137 self.qemu_img = \ 138 os.environ.get('QEMU_IMG', 'qemu-img').strip().split(' ') 139 self.qemu_io = os.environ.get('QEMU_IO', 'qemu-io').strip().split(' ') 140 self.commands = [['qemu-img', 'check', '-f', 'qcow2', '$test_img'], 141 ['qemu-img', 'info', '-f', 'qcow2', '$test_img'], 142 ['qemu-io', '$test_img', '-c', 'read $off $len'], 143 ['qemu-io', '$test_img', '-c', 'write $off $len'], 144 ['qemu-io', '$test_img', '-c', 145 'aio_read $off $len'], 146 ['qemu-io', '$test_img', '-c', 147 'aio_write $off $len'], 148 ['qemu-io', '$test_img', '-c', 'flush'], 149 ['qemu-io', '$test_img', '-c', 150 'discard $off $len'], 151 ['qemu-io', '$test_img', '-c', 152 'truncate $off']] 153 for fmt in ['raw', 'vmdk', 'vdi', 'qcow2', 'file', 'qed', 'vpc']: 154 self.commands.append( 155 ['qemu-img', 'convert', '-f', 'qcow2', '-O', fmt, 156 '$test_img', 'converted_image.' + fmt]) 157 158 try: 159 os.makedirs(self.current_dir) 160 except OSError, e: 161 print >>sys.stderr, \ 162 "Error: The working directory '%s' cannot be used. Reason: %s"\ 163 % (self.work_dir, e[1]) 164 raise TestException 165 self.log = open(os.path.join(self.current_dir, "test.log"), "w") 166 self.parent_log = open(run_log, "a") 167 self.failed = False 168 self.cleanup = cleanup 169 self.log_all = log_all 170 171 def _create_backing_file(self): 172 """Create a backing file in the current directory. 173 174 Return a tuple of a backing file name and format. 175 176 Format of a backing file is randomly chosen from all formats supported 177 by 'qemu-img create'. 178 """ 179 # All formats supported by the 'qemu-img create' command. 180 backing_file_fmt = random.choice(['raw', 'vmdk', 'vdi', 'qcow2', 181 'file', 'qed', 'vpc']) 182 backing_file_name = 'backing_img.' + backing_file_fmt 183 backing_file_size = random.randint(MIN_BACKING_FILE_SIZE, 184 MAX_BACKING_FILE_SIZE) * (1 << 20) 185 cmd = self.qemu_img + ['create', '-f', backing_file_fmt, 186 backing_file_name, str(backing_file_size)] 187 temp_log = StringIO.StringIO() 188 retcode = run_app(temp_log, cmd) 189 if retcode == 0: 190 temp_log.close() 191 return (backing_file_name, backing_file_fmt) 192 else: 193 multilog("Warning: The %s backing file was not created.\n\n" 194 % backing_file_fmt, sys.stderr, self.log, self.parent_log) 195 self.log.write("Log for the failure:\n" + temp_log.getvalue() + 196 '\n\n') 197 temp_log.close() 198 return (None, None) 199 200 def execute(self, input_commands=None, fuzz_config=None): 201 """ Execute a test. 202 203 The method creates backing and test images, runs test app and analyzes 204 its exit status. If the application was killed by a signal, the test 205 is marked as failed. 206 """ 207 if input_commands is None: 208 commands = self.commands 209 else: 210 commands = input_commands 211 212 os.chdir(self.current_dir) 213 backing_file_name, backing_file_fmt = self._create_backing_file() 214 img_size = image_generator.create_image( 215 'test.img', backing_file_name, backing_file_fmt, fuzz_config) 216 for item in commands: 217 shutil.copy('test.img', 'copy.img') 218 # 'off' and 'len' are multiple of the sector size 219 sector_size = 512 220 start = random.randrange(0, img_size + 1, sector_size) 221 end = random.randrange(start, img_size + 1, sector_size) 222 223 if item[0] == 'qemu-img': 224 current_cmd = list(self.qemu_img) 225 elif item[0] == 'qemu-io': 226 current_cmd = list(self.qemu_io) 227 else: 228 multilog("Warning: test command '%s' is not defined.\n" 229 % item[0], sys.stderr, self.log, self.parent_log) 230 continue 231 # Replace all placeholders with their real values 232 for v in item[1:]: 233 c = (v 234 .replace('$test_img', 'copy.img') 235 .replace('$off', str(start)) 236 .replace('$len', str(end - start))) 237 current_cmd.append(c) 238 239 # Log string with the test header 240 test_summary = "Seed: %s\nCommand: %s\nTest directory: %s\n" \ 241 "Backing file: %s\n" \ 242 % (self.seed, " ".join(current_cmd), 243 self.current_dir, backing_file_name) 244 temp_log = StringIO.StringIO() 245 try: 246 retcode = run_app(temp_log, current_cmd) 247 except OSError, e: 248 multilog("%sError: Start of '%s' failed. Reason: %s\n\n" 249 % (test_summary, os.path.basename(current_cmd[0]), 250 e[1]), 251 sys.stderr, self.log, self.parent_log) 252 raise TestException 253 254 if retcode < 0: 255 self.log.write(temp_log.getvalue()) 256 multilog("%sFAIL: Test terminated by signal %s\n\n" 257 % (test_summary, str_signal(-retcode)), 258 sys.stderr, self.log, self.parent_log) 259 self.failed = True 260 else: 261 if self.log_all: 262 self.log.write(temp_log.getvalue()) 263 multilog("%sPASS: Application exited with the code " \ 264 "'%d'\n\n" % (test_summary, retcode), 265 sys.stdout, self.log, self.parent_log) 266 temp_log.close() 267 os.remove('copy.img') 268 269 def finish(self): 270 """Restore the test environment after a test execution.""" 271 self.log.close() 272 self.parent_log.close() 273 os.chdir(self.init_path) 274 if self.cleanup and not self.failed: 275 shutil.rmtree(self.current_dir) 276 277if __name__ == '__main__': 278 279 def usage(): 280 print """ 281 Usage: runner.py [OPTION...] TEST_DIR IMG_GENERATOR 282 283 Set up test environment in TEST_DIR and run a test in it. A module for 284 test image generation should be specified via IMG_GENERATOR. 285 286 Example: 287 runner.py -c '[["qemu-img", "info", "$test_img"]]' /tmp/test qcow2 288 289 Optional arguments: 290 -h, --help display this help and exit 291 -d, --duration=NUMBER finish tests after NUMBER of seconds 292 -c, --command=JSON run tests for all commands specified in 293 the JSON array 294 -s, --seed=STRING seed for a test image generation, 295 by default will be generated randomly 296 --config=JSON take fuzzer configuration from the JSON 297 array 298 -k, --keep_passed don't remove folders of passed tests 299 -v, --verbose log information about passed tests 300 301 JSON: 302 303 '--command' accepts a JSON array of commands. Each command presents 304 an application under test with all its parameters as a list of strings, 305 e.g. ["qemu-io", "$test_img", "-c", "write $off $len"]. 306 307 Supported application aliases: 'qemu-img' and 'qemu-io'. 308 309 Supported argument aliases: $test_img for the fuzzed image, $off 310 for an offset, $len for length. 311 312 Values for $off and $len will be generated based on the virtual disk 313 size of the fuzzed image. 314 315 Paths to 'qemu-img' and 'qemu-io' are retrevied from 'QEMU_IMG' and 316 'QEMU_IO' environment variables. 317 318 '--config' accepts a JSON array of fields to be fuzzed, e.g. 319 '[["header"], ["header", "version"]]'. 320 321 Each of the list elements can consist of a complex image element only 322 as ["header"] or ["feature_name_table"] or an exact field as 323 ["header", "version"]. In the first case random portion of the element 324 fields will be fuzzed, in the second one the specified field will be 325 fuzzed always. 326 327 If '--config' argument is specified, fields not listed in 328 the configuration array will not be fuzzed. 329 """ 330 331 def run_test(test_id, seed, work_dir, run_log, cleanup, log_all, 332 command, fuzz_config): 333 """Setup environment for one test and execute this test.""" 334 try: 335 test = TestEnv(test_id, seed, work_dir, run_log, cleanup, 336 log_all) 337 except TestException: 338 sys.exit(1) 339 340 # Python 2.4 doesn't support 'finally' and 'except' in the same 'try' 341 # block 342 try: 343 try: 344 test.execute(command, fuzz_config) 345 except TestException: 346 sys.exit(1) 347 finally: 348 test.finish() 349 350 def should_continue(duration, start_time): 351 """Return True if a new test can be started and False otherwise.""" 352 current_time = int(time.time()) 353 return (duration is None) or (current_time - start_time < duration) 354 355 try: 356 opts, args = getopt.gnu_getopt(sys.argv[1:], 'c:hs:kvd:', 357 ['command=', 'help', 'seed=', 'config=', 358 'keep_passed', 'verbose', 'duration=']) 359 except getopt.error, e: 360 print >>sys.stderr, \ 361 "Error: %s\n\nTry 'runner.py --help' for more information" % e 362 sys.exit(1) 363 364 command = None 365 cleanup = True 366 log_all = False 367 seed = None 368 config = None 369 duration = None 370 for opt, arg in opts: 371 if opt in ('-h', '--help'): 372 usage() 373 sys.exit() 374 elif opt in ('-c', '--command'): 375 try: 376 command = json.loads(arg) 377 except (TypeError, ValueError, NameError), e: 378 print >>sys.stderr, \ 379 "Error: JSON array of test commands cannot be loaded.\n" \ 380 "Reason: %s" % e 381 sys.exit(1) 382 elif opt in ('-k', '--keep_passed'): 383 cleanup = False 384 elif opt in ('-v', '--verbose'): 385 log_all = True 386 elif opt in ('-s', '--seed'): 387 seed = arg 388 elif opt in ('-d', '--duration'): 389 duration = int(arg) 390 elif opt == '--config': 391 try: 392 config = json.loads(arg) 393 except (TypeError, ValueError, NameError), e: 394 print >>sys.stderr, \ 395 "Error: JSON array with the fuzzer configuration cannot" \ 396 " be loaded\nReason: %s" % e 397 sys.exit(1) 398 399 if not len(args) == 2: 400 print >>sys.stderr, \ 401 "Expected two parameters\nTry 'runner.py --help'" \ 402 " for more information." 403 sys.exit(1) 404 405 work_dir = os.path.realpath(args[0]) 406 # run_log is created in 'main', because multiple tests are expected to 407 # log in it 408 run_log = os.path.join(work_dir, 'run.log') 409 410 # Add the path to the image generator module to sys.path 411 sys.path.append(os.path.realpath(os.path.dirname(args[1]))) 412 # Remove a script extension from image generator module if any 413 generator_name = os.path.splitext(os.path.basename(args[1]))[0] 414 415 try: 416 image_generator = __import__(generator_name) 417 except ImportError, e: 418 print >>sys.stderr, \ 419 "Error: The image generator '%s' cannot be imported.\n" \ 420 "Reason: %s" % (generator_name, e) 421 sys.exit(1) 422 423 # Enable core dumps 424 resource.setrlimit(resource.RLIMIT_CORE, (-1, -1)) 425 # If a seed is specified, only one test will be executed. 426 # Otherwise runner will terminate after a keyboard interruption 427 start_time = int(time.time()) 428 test_id = count(1) 429 while should_continue(duration, start_time): 430 try: 431 run_test(str(test_id.next()), seed, work_dir, run_log, cleanup, 432 log_all, command, config) 433 except (KeyboardInterrupt, SystemExit): 434 sys.exit(1) 435 436 if seed is not None: 437 break 438