Add DropPrivileges()

tools/exception_port_tool.cc

Index: tools/exception_port_tool.cc
diff --git a/tools/exception_port_tool.cc b/tools/exception_port_tool.cc
index bcca29fcdd5ec0096f11c181fd20ffe4fe2e0750..81eca6bbf204db283f63e8bcf11f3b23a229bc77 100644
--- a/tools/exception_port_tool.cc
+++ b/tools/exception_port_tool.cc
@@ -34,6 +34,7 @@
 #include "util/mach/mach_extensions.h"
 #include "util/mach/symbolic_constants_mach.h"
 #include "util/mach/task_for_pid.h"
+#include "util/posix/drop_privileges.h"
 #include "util/stdlib/string_number_conversion.h"
 
 namespace crashpad {
@@ -503,6 +504,10 @@ int ExceptionPortToolMain(int argc, char* argv[]) {
     alternate_task_owner.reset(options.alternate_task);
   }
 
+  // This tool may have been installed as a setuid binary so that TaskForPID()
+  // could succeed. Drop any privileges now that they’re no longer necessary.
+  DropPrivileges();
+
   MachSendRightPool mach_send_right_pool;
 
   // Show bootstrap services requested.