Revert of Roll Clang 223108:230631 (+revert of r229678)

sandbox/linux/integration_tests/bpf_dsl_seccomp_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <errno.h>
 #include <fcntl.h>
 #include <pthread.h>
 #include <sched.h>
 #include <signal.h>
 #include <sys/prctl.h>
@@ skipping 633 matching lines @@
   setenv(kSandboxDebuggingEnv, "t", 0);
   Die::SuppressInfoMessages(true);
 
   // Some system calls must always be allowed, if our policy wants to make
   // use of UnsafeTrap()
   if (SandboxBPF::IsRequiredForUnsafeTrap(sysno))
     return Allow();
   return UnsafeTrap(AllowRedirectedSyscall, NULL);
 }
 
-#if !defined(ADDRESS_SANITIZER)
-// ASan does not allow changing the signal handler for SIGBUS, and treats it as
-// a fatal signal.
-
 int bus_handler_fd_ = -1;
 
 void SigBusHandler(int, siginfo_t* info, void* void_context) {
   BPF_ASSERT(write(bus_handler_fd_, "\x55", 1) == 1);
 }
 
 BPF_TEST_C(SandboxBPF, SigBus, RedirectAllSyscallsPolicy) {
   // We use the SIGBUS bit in the signal mask as a thread-local boolean
   // value in the implementation of UnsafeTrap(). This is obviously a bit
   // of a hack that could conceivably interfere with code that uses SIGBUS
   // in more traditional ways. This test verifies that basic functionality
   // of SIGBUS is not impacted, but it is certainly possibly to construe
   // more complex uses of signals where our use of the SIGBUS mask is not
   // 100% transparent. This is expected behavior.
   int fds[2];
   BPF_ASSERT(socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0);
   bus_handler_fd_ = fds[1];
   struct sigaction sa = {};
   sa.sa_sigaction = SigBusHandler;
   sa.sa_flags = SA_SIGINFO;
   BPF_ASSERT(sigaction(SIGBUS, &sa, NULL) == 0);
   raise(SIGBUS);
   char c = '\000';
   BPF_ASSERT(read(fds[0], &c, 1) == 1);
   BPF_ASSERT(close(fds[0]) == 0);
   BPF_ASSERT(close(fds[1]) == 0);
   BPF_ASSERT(c == 0x55);
 }
-#endif  // !defined(ADDRESS_SANITIZER)
 
 BPF_TEST_C(SandboxBPF, SigMask, RedirectAllSyscallsPolicy) {
   // Signal masks are potentially tricky to handle. For instance, if we
   // ever tried to update them from inside a Trap() or UnsafeTrap() handler,
   // the call to sigreturn() at the end of the signal handler would undo
   // all of our efforts. So, it makes sense to test that sigprocmask()
   // works, even if we have a policy in place that makes use of UnsafeTrap().
   // In practice, this works because we force sigprocmask() to be handled
   // entirely in the kernel.
   sigset_t mask0, mask1, mask2;
@@ skipping 1553 matching lines @@
   BPF_ASSERT_EQ(ENOSYS, errno);
 
   BPF_ASSERT_EQ(-1, syscall(__NR_setgid, 300));
   BPF_ASSERT_EQ(EPERM, errno);
 }
 
 }  // namespace
 
 }  // namespace bpf_dsl
 }  // namespace sandbox