sandbox/linux/tests/unit_tests.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <fcntl.h>
   6 #include <poll.h>
   7 #include <signal.h>
   8 #include <stdio.h>
   9 #include <sys/resource.h>
  10 #include <sys/types.h>
  11 #include <sys/wait.h>
  12 #include <sys/time.h>
  13 #include <time.h>
  14 #include <unistd.h>
  15
  16 #include "base/debug/leak_annotations.h"
  17 #include "base/files/file_util.h"
  18 #include "base/posix/eintr_wrapper.h"
  19 #include "base/third_party/valgrind/valgrind.h"
  20 #include "build/build_config.h"
  21 #include "sandbox/linux/tests/unit_tests.h"
  22
  23 // Specifically, PNaCl toolchain does not have this flag.
  24 #if !defined(POLLRDHUP)
  25 #define POLLRDHUP 0x2000
  26 #endif
  27
  28 namespace {
  29 std::string TestFailedMessage(const std::string& msg) {
  30   return msg.empty() ? std::string() : "Actual test failure: " + msg;
  31 }
  32
  33 int GetSubProcessTimeoutTimeInSeconds() {
  34   // Previously 10s, but that timed out (just) on Chromecast.
  35   return 12;
  36 }
  37
  38 // Returns the number of threads of the current process or -1.
  39 int CountThreads() {
  40   struct stat task_stat;
  41   int task_d = stat("/proc/self/task", &task_stat);
  42   // task_stat.st_nlink should be the number of tasks + 2 (accounting for
  43   // "." and "..".
  44   if (task_d != 0 || task_stat.st_nlink < 3)
  45     return -1;
  46   const int num_threads = task_stat.st_nlink - 2;
  47   return num_threads;
  48 }
  49
  50 }  // namespace
  51
  52 namespace sandbox {
  53
  54 bool IsAndroid() {
  55 #if defined(OS_ANDROID)
  56   return true;
  57 #else
  58   return false;
  59 #endif
  60 }
  61
  62 bool IsArchitectureArm() {
  63 #if defined(ARCH_CPU_ARM_FAMILY)
  64   return true;
  65 #else
  66   return false;
  67 #endif
  68 }
  69
  70 // TODO(jln): figure out why base/.../dynamic_annotations.h's
  71 // RunningOnValgrind() cannot link.
  72 bool IsRunningOnValgrind() { return RUNNING_ON_VALGRIND; }
  73
  74 static const int kExpectedValue = 42;
  75 static const int kIgnoreThisTest = 43;
  76 static const int kExitWithAssertionFailure = 1;
  77 #if !defined(OS_NACL_NONSFI)
  78 static const int kExitForTimeout = 2;
  79 #endif
  80
  81 #if defined(SANDBOX_USES_BASE_TEST_SUITE)
  82 // This is due to StackDumpSignalHandler() performing _exit(1).
  83 // TODO(jln): get rid of the collision with kExitWithAssertionFailure.
  84 const int kExitAfterSIGSEGV = 1;
  85 #endif
  86
  87 // PNaCl toolchain's signal ABIs are incompatible with Linux's.
  88 // So, for simplicity, just drop the "timeout" feature from unittest framework
  89 // with relying on the buildbot's timeout feature.
  90 #if !defined(OS_NACL_NONSFI)
  91 static void SigAlrmHandler(int) {
  92   const char failure_message[] = "Timeout reached!\n";
  93   // Make sure that we never block here.
  94   if (!fcntl(2, F_SETFL, O_NONBLOCK)) {
  95     ignore_result(write(2, failure_message, sizeof(failure_message) - 1));
  96   }
  97   _exit(kExitForTimeout);
  98 }
  99
 100 // Set a timeout with a handler that will automatically fail the
 101 // test.
 102 static void SetProcessTimeout(int time_in_seconds) {
 103   struct sigaction act = {};
 104   act.sa_handler = SigAlrmHandler;
 105   SANDBOX_ASSERT(sigemptyset(&act.sa_mask) == 0);
 106   act.sa_flags = 0;
 107
 108   struct sigaction old_act;
 109   SANDBOX_ASSERT(sigaction(SIGALRM, &act, &old_act) == 0);
 110
 111   // We don't implemenet signal chaining, so make sure that nothing else
 112   // is expecting to handle SIGALRM.
 113   SANDBOX_ASSERT((old_act.sa_flags & SA_SIGINFO) == 0);
 114   SANDBOX_ASSERT(old_act.sa_handler == SIG_DFL);
 115   sigset_t sigalrm_set;
 116   SANDBOX_ASSERT(sigemptyset(&sigalrm_set) == 0);
 117   SANDBOX_ASSERT(sigaddset(&sigalrm_set, SIGALRM) == 0);
 118   SANDBOX_ASSERT(sigprocmask(SIG_UNBLOCK, &sigalrm_set, NULL) == 0);
 119   SANDBOX_ASSERT(alarm(time_in_seconds) == 0);  // There should be no previous
 120                                                 // alarm.
 121 }
 122 #endif  // !defined(OS_NACL_NONSFI)
 123
 124 // Runs a test in a sub-process. This is necessary for most of the code
 125 // in the BPF sandbox, as it potentially makes global state changes and as
 126 // it also tends to raise fatal errors, if the code has been used in an
 127 // insecure manner.
 128 void UnitTests::RunTestInProcess(SandboxTestRunner* test_runner,
 129                                  DeathCheck death,
 130                                  const void* death_aux) {
 131   CHECK(test_runner);
 132   // We need to fork(), so we can't be multi-threaded, as threads could hold
 133   // locks.
 134   int num_threads = CountThreads();
 135 #if !defined(THREAD_SANITIZER)
 136   const int kNumExpectedThreads = 1;
 137 #else
 138   // Under TSAN, there is a special helper thread. It should be completely
 139   // invisible to our testing, so we ignore it. It should be ok to fork()
 140   // with this thread. It's currently buggy, but it's the best we can do until
 141   // there is a way to delay the start of the thread
 142   // (https://code.google.com/p/thread-sanitizer/issues/detail?id=19).
 143   const int kNumExpectedThreads = 2;
 144 #endif
 145
 146   // The kernel is at liberty to wake a thread id futex before updating /proc.
 147   // If another test running in the same process has stopped a thread, it may
 148   // appear as still running in /proc.
 149   // We poll /proc, with an exponential back-off. At most, we'll sleep around
 150   // 2^iterations nanoseconds in nanosleep().
 151   for (unsigned int iteration = 0; iteration < 30; iteration++) {
 152     struct timespec ts = {0, 1L << iteration /* nanoseconds */};
 153     PCHECK(0 == HANDLE_EINTR(nanosleep(&ts, &ts)));
 154     num_threads = CountThreads();
 155     if (kNumExpectedThreads == num_threads)
 156       break;
 157   }
 158
 159   ASSERT_EQ(kNumExpectedThreads, num_threads)
 160       << "Running sandbox tests with multiple threads "
 161       << "is not supported and will make the tests flaky.";
 162   int fds[2];
 163   ASSERT_EQ(0, pipe(fds));
 164   // Check that our pipe is not on one of the standard file descriptor.
 165   SANDBOX_ASSERT(fds[0] > 2 && fds[1] > 2);
 166
 167   pid_t pid;
 168   ASSERT_LE(0, (pid = fork()));
 169   if (!pid) {
 170     // In child process
 171     // Redirect stderr to our pipe. This way, we can capture all error
 172     // messages, if we decide we want to do so in our tests.
 173     SANDBOX_ASSERT(dup2(fds[1], 2) == 2);
 174     SANDBOX_ASSERT(!close(fds[0]));
 175     SANDBOX_ASSERT(!close(fds[1]));
 176
 177     // Don't set a timeout if running on Valgrind, since it's generally much
 178     // slower.
 179     if (!IsRunningOnValgrind()) {
 180 #if !defined(OS_NACL_NONSFI)
 181       SetProcessTimeout(GetSubProcessTimeoutTimeInSeconds());
 182 #endif
 183     }
 184
 185     // Disable core files. They are not very useful for our individual test
 186     // cases.
 187     struct rlimit no_core = {0};
 188     setrlimit(RLIMIT_CORE, &no_core);
 189
 190     test_runner->Run();
 191     if (test_runner->ShouldCheckForLeaks()) {
 192 #if defined(LEAK_SANITIZER)
 193       __lsan_do_leak_check();
 194 #endif
 195     }
 196     _exit(kExpectedValue);
 197   }
 198
 199   close(fds[1]);
 200   std::vector<char> msg_buf;
 201   ssize_t rc;
 202
 203   // Make sure read() will never block as we'll use poll() to
 204   // block with a timeout instead.
 205   const int fcntl_ret = fcntl(fds[0], F_SETFL, O_NONBLOCK);
 206   ASSERT_EQ(0, fcntl_ret);
 207   struct pollfd poll_fd = {fds[0], POLLIN | POLLRDHUP, 0};
 208
 209   int poll_ret;
 210   // We prefer the SIGALRM timeout to trigger in the child than this timeout
 211   // so we double the common value here.
 212   int poll_timeout = GetSubProcessTimeoutTimeInSeconds() * 2 * 1000;
 213   while ((poll_ret = poll(&poll_fd, 1, poll_timeout) > 0)) {
 214     const size_t kCapacity = 256;
 215     const size_t len = msg_buf.size();
 216     msg_buf.resize(len + kCapacity);
 217     rc = HANDLE_EINTR(read(fds[0], &msg_buf[len], kCapacity));
 218     msg_buf.resize(len + std::max(rc, static_cast<ssize_t>(0)));
 219     if (rc <= 0)
 220       break;
 221   }
 222   ASSERT_NE(poll_ret, -1) << "poll() failed";
 223   ASSERT_NE(poll_ret, 0) << "Timeout while reading child state";
 224   close(fds[0]);
 225   std::string msg(msg_buf.begin(), msg_buf.end());
 226
 227   int status = 0;
 228   int waitpid_returned = HANDLE_EINTR(waitpid(pid, &status, 0));
 229   ASSERT_EQ(pid, waitpid_returned) << TestFailedMessage(msg);
 230
 231   // At run-time, we sometimes decide that a test shouldn't actually
 232   // run (e.g. when testing sandbox features on a kernel that doesn't
 233   // have sandboxing support). When that happens, don't attempt to
 234   // call the "death" function, as it might be looking for a
 235   // death-test condition that would never have triggered.
 236   if (!WIFEXITED(status) || WEXITSTATUS(status) != kIgnoreThisTest ||
 237       !msg.empty()) {
 238     // We use gtest's ASSERT_XXX() macros instead of the DeathCheck
 239     // functions.  This means, on failure, "return" is called. This
 240     // only works correctly, if the call of the "death" callback is
 241     // the very last thing in our function.
 242     death(status, msg, death_aux);
 243   }
 244 }
 245
 246 void UnitTests::DeathSuccess(int status, const std::string& msg, const void*) {
 247   std::string details(TestFailedMessage(msg));
 248
 249   bool subprocess_terminated_normally = WIFEXITED(status);
 250   ASSERT_TRUE(subprocess_terminated_normally) << details;
 251   int subprocess_exit_status = WEXITSTATUS(status);
 252   ASSERT_EQ(kExpectedValue, subprocess_exit_status) << details;
 253   bool subprocess_exited_but_printed_messages = !msg.empty();
 254   EXPECT_FALSE(subprocess_exited_but_printed_messages) << details;
 255 }
 256
 257 void UnitTests::DeathSuccessAllowNoise(int status,
 258                                        const std::string& msg,
 259                                        const void*) {
 260   std::string details(TestFailedMessage(msg));
 261
 262   bool subprocess_terminated_normally = WIFEXITED(status);
 263   ASSERT_TRUE(subprocess_terminated_normally) << details;
 264   int subprocess_exit_status = WEXITSTATUS(status);
 265   ASSERT_EQ(kExpectedValue, subprocess_exit_status) << details;
 266 }
 267
 268 void UnitTests::DeathMessage(int status,
 269                              const std::string& msg,
 270                              const void* aux) {
 271   std::string details(TestFailedMessage(msg));
 272   const char* expected_msg = static_cast<const char*>(aux);
 273
 274   bool subprocess_terminated_normally = WIFEXITED(status);
 275   ASSERT_TRUE(subprocess_terminated_normally) << "Exit status: " << status
 276                                               << " " << details;
 277   int subprocess_exit_status = WEXITSTATUS(status);
 278   ASSERT_EQ(1, subprocess_exit_status) << details;
 279
 280   bool subprocess_exited_without_matching_message =
 281       msg.find(expected_msg) == std::string::npos;
 282
 283 // In official builds CHECK messages are dropped, so look for SIGABRT.
 284 // See https://code.google.com/p/chromium/issues/detail?id=437312
 285 #if defined(OFFICIAL_BUILD) && defined(NDEBUG) && !defined(OS_ANDROID)
 286   if (subprocess_exited_without_matching_message) {
 287     static const char kSigAbortMessage[] = "Received signal 6";
 288     subprocess_exited_without_matching_message =
 289         msg.find(kSigAbortMessage) == std::string::npos;
 290   }
 291 #endif
 292   EXPECT_FALSE(subprocess_exited_without_matching_message) << details;
 293 }
 294
 295 void UnitTests::DeathSEGVMessage(int status,
 296                                  const std::string& msg,
 297                                  const void* aux) {
 298   std::string details(TestFailedMessage(msg));
 299   const char* expected_msg = static_cast<const char*>(aux);
 300
 301 #if !defined(SANDBOX_USES_BASE_TEST_SUITE)
 302   const bool subprocess_got_sigsegv =
 303       WIFSIGNALED(status) && (SIGSEGV == WTERMSIG(status));
 304 #else
 305   // This hack is required when a signal handler is installed
 306   // for SEGV that will _exit(1).
 307   const bool subprocess_got_sigsegv =
 308       WIFEXITED(status) && (kExitAfterSIGSEGV == WEXITSTATUS(status));
 309 #endif
 310
 311   ASSERT_TRUE(subprocess_got_sigsegv) << "Exit status: " << status
 312                                       << " " << details;
 313
 314   bool subprocess_exited_without_matching_message =
 315       msg.find(expected_msg) == std::string::npos;
 316   EXPECT_FALSE(subprocess_exited_without_matching_message) << details;
 317 }
 318
 319 void UnitTests::DeathExitCode(int status,
 320                               const std::string& msg,
 321                               const void* aux) {
 322   int expected_exit_code = static_cast<int>(reinterpret_cast<intptr_t>(aux));
 323   std::string details(TestFailedMessage(msg));
 324
 325   bool subprocess_terminated_normally = WIFEXITED(status);
 326   ASSERT_TRUE(subprocess_terminated_normally) << details;
 327   int subprocess_exit_status = WEXITSTATUS(status);
 328   ASSERT_EQ(expected_exit_code, subprocess_exit_status) << details;
 329 }
 330
 331 void UnitTests::DeathBySignal(int status,
 332                               const std::string& msg,
 333                               const void* aux) {
 334   int expected_signo = static_cast<int>(reinterpret_cast<intptr_t>(aux));
 335   std::string details(TestFailedMessage(msg));
 336
 337   bool subprocess_terminated_by_signal = WIFSIGNALED(status);
 338   ASSERT_TRUE(subprocess_terminated_by_signal) << details;
 339   int subprocess_signal_number = WTERMSIG(status);
 340   ASSERT_EQ(expected_signo, subprocess_signal_number) << details;
 341 }
 342
 343 void UnitTests::AssertionFailure(const char* expr, const char* file, int line) {
 344   fprintf(stderr, "%s:%d:%s", file, line, expr);
 345   fflush(stderr);
 346   _exit(kExitWithAssertionFailure);
 347 }
 348
 349 void UnitTests::IgnoreThisTest() {
 350   fflush(stderr);
 351   _exit(kIgnoreThisTest);
 352 }
 353
 354 }  // namespace