handler/mac: Log a warning when an exception message has a suspicious

util/mach/exception_ports_test.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // 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,
@@ skipping 179 matching lines @@
     if (exception == EXC_CRASH && code_count >= 1) {
       int signal;
       ExcCrashRecoverOriginalException(code[0], nullptr, &signal);
 
       // The child crashed with __builtin_trap(), which shows up as SIGILL.
       EXPECT_EQ(SIGILL, signal);
 
       SetExpectedChildTermination(kTerminationSignal, signal);
     }
 
+    EXPECT_EQ(0, AuditPIDFromMachMessageTrailer(trailer));
+
     return ExcServerSuccessfulReturnValue(behavior, false);
   }
 
  private:
   class Child {
    public:
     explicit Child(TestExceptionPorts* test_exception_ports)
         : test_exception_ports_(test_exception_ports),
           thread_(),
           init_semaphore_(0),
@@ skipping 226 matching lines @@
     c = '\0';
     CheckedWriteFile(WritePipeHandle(), &c, 1);
 
     if (who_crashes_ != kNobodyCrashes) {
       UniversalMachExcServer universal_mach_exc_server(this);
 
       const mach_msg_timeout_t kTimeoutMs = 50;
       kern_return_t kr =
           MachMessageServer::Run(&universal_mach_exc_server,
                                  local_port,
-                                 MACH_MSG_OPTION_NONE,
+                                 kMachMessageReceiveAuditTrailer,
                                  MachMessageServer::kOneShot,
                                  MachMessageServer::kReceiveLargeError,
                                  kTimeoutMs);
       EXPECT_EQ(KERN_SUCCESS, kr)
           << MachErrorMessage(kr, "MachMessageServer::Run");
 
       EXPECT_TRUE(handled_);
     }
 
     // Wait for the child process to exit or terminate, as indicated by it
@@ skipping 147 matching lines @@
   if (geteuid() == 0) {
     EXPECT_TRUE(rv);
   } else {
     EXPECT_FALSE(rv);
   }
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad