libsanitizer/asan/asan_win_dynamic_runtime_thunk.cc

   1 //===-- asan_win_dynamic_runtime_thunk.cc ---------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // This file defines things that need to be present in the application modules
  11 // to interact with the ASan DLL runtime correctly and can't be implemented
  12 // using the default "import library" generated when linking the DLL RTL.
  13 //
  14 // This includes:
  15 //  - creating weak aliases to default implementation imported from asan dll.
  16 //  - forwarding the detect_stack_use_after_return runtime option
  17 //  - working around deficiencies of the MD runtime
  18 //  - installing a custom SEH handler
  19 //
  20 //===----------------------------------------------------------------------===//
  21
  22 #ifdef SANITIZER_DYNAMIC_RUNTIME_THUNK
  23 #define SANITIZER_IMPORT_INTERFACE 1
  24 #include "sanitizer_common/sanitizer_win_defs.h"
  25 #define WIN32_LEAN_AND_MEAN
  26 #include <windows.h>
  27
  28 // Define weak alias for all weak functions imported from asan dll.
  29 #define INTERFACE_FUNCTION(Name)
  30 #define INTERFACE_WEAK_FUNCTION(Name) WIN_WEAK_IMPORT_DEF(Name)
  31 #include "asan_interface.inc"
  32
  33 // First, declare CRT sections we'll be using in this file
  34 #pragma section(".CRT$XIB", long, read)  // NOLINT
  35 #pragma section(".CRT$XID", long, read)  // NOLINT
  36 #pragma section(".CRT$XCAB", long, read)  // NOLINT
  37 #pragma section(".CRT$XTW", long, read)  // NOLINT
  38 #pragma section(".CRT$XTY", long, read)  // NOLINT
  39 #pragma section(".CRT$XLAB", long, read)  // NOLINT
  40
  41 ////////////////////////////////////////////////////////////////////////////////
  42 // Define a copy of __asan_option_detect_stack_use_after_return that should be
  43 // used when linking an MD runtime with a set of object files on Windows.
  44 //
  45 // The ASan MD runtime dllexports '__asan_option_detect_stack_use_after_return',
  46 // so normally we would just dllimport it.  Unfortunately, the dllimport
  47 // attribute adds __imp_ prefix to the symbol name of a variable.
  48 // Since in general we don't know if a given TU is going to be used
  49 // with a MT or MD runtime and we don't want to use ugly __imp_ names on Windows
  50 // just to work around this issue, let's clone the variable that is constant
  51 // after initialization anyways.
  52 extern "C" {
  53 __declspec(dllimport) int __asan_should_detect_stack_use_after_return();
  54 int __asan_option_detect_stack_use_after_return;
  55
  56 __declspec(dllimport) void* __asan_get_shadow_memory_dynamic_address();
  57 void* __asan_shadow_memory_dynamic_address;
  58 }
  59
  60 static int InitializeClonedVariables() {
  61   __asan_option_detect_stack_use_after_return =
  62     __asan_should_detect_stack_use_after_return();
  63   __asan_shadow_memory_dynamic_address =
  64     __asan_get_shadow_memory_dynamic_address();
  65   return 0;
  66 }
  67
  68 static void NTAPI asan_thread_init(void *mod, unsigned long reason,
  69     void *reserved) {
  70   if (reason == DLL_PROCESS_ATTACH) InitializeClonedVariables();
  71 }
  72
  73 // Our cloned variables must be initialized before C/C++ constructors.  If TLS
  74 // is used, our .CRT$XLAB initializer will run first. If not, our .CRT$XIB
  75 // initializer is needed as a backup.
  76 __declspec(allocate(".CRT$XIB")) int (*__asan_initialize_cloned_variables)() =
  77     InitializeClonedVariables;
  78 __declspec(allocate(".CRT$XLAB")) void (NTAPI *__asan_tls_init)(void *,
  79     unsigned long, void *) = asan_thread_init;
  80
  81 ////////////////////////////////////////////////////////////////////////////////
  82 // For some reason, the MD CRT doesn't call the C/C++ terminators during on DLL
  83 // unload or on exit.  ASan relies on LLVM global_dtors to call
  84 // __asan_unregister_globals on these events, which unfortunately doesn't work
  85 // with the MD runtime, see PR22545 for the details.
  86 // To work around this, for each DLL we schedule a call to UnregisterGlobals
  87 // using atexit() that calls a small subset of C terminators
  88 // where LLVM global_dtors is placed.  Fingers crossed, no other C terminators
  89 // are there.
  90 extern "C" int __cdecl atexit(void (__cdecl *f)(void));
  91 extern "C" void __cdecl _initterm(void *a, void *b);
  92
  93 namespace {
  94 __declspec(allocate(".CRT$XTW")) void* before_global_dtors = 0;
  95 __declspec(allocate(".CRT$XTY")) void* after_global_dtors = 0;
  96
  97 void UnregisterGlobals() {
  98   _initterm(&before_global_dtors, &after_global_dtors);
  99 }
 100
 101 int ScheduleUnregisterGlobals() {
 102   return atexit(UnregisterGlobals);
 103 }
 104 }  // namespace
 105
 106 // We need to call 'atexit(UnregisterGlobals);' as early as possible, but after
 107 // atexit() is initialized (.CRT$XIC).  As this is executed before C++
 108 // initializers (think ctors for globals), UnregisterGlobals gets executed after
 109 // dtors for C++ globals.
 110 __declspec(allocate(".CRT$XID"))
 111 int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
 112
 113 ////////////////////////////////////////////////////////////////////////////////
 114 // ASan SEH handling.
 115 // We need to set the ASan-specific SEH handler at the end of CRT initialization
 116 // of each module (see also asan_win.cc).
 117 extern "C" {
 118 __declspec(dllimport) int __asan_set_seh_filter();
 119 static int SetSEHFilter() { return __asan_set_seh_filter(); }
 120
 121 // Unfortunately, putting a pointer to __asan_set_seh_filter into
 122 // __asan_intercept_seh gets optimized out, so we have to use an extra function.
 123 __declspec(allocate(".CRT$XCAB")) int (*__asan_seh_interceptor)() =
 124     SetSEHFilter;
 125 }
 126
 127 WIN_FORCE_LINK(__asan_dso_reg_hook)
 128
 129 #endif // SANITIZER_DYNAMIC_RUNTIME_THUNK