libsanitizer/asan/asan_win_dynamic_runtime_thunk.cpp

   1 //===-- asan_win_dynamic_runtime_thunk.cpp --------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of AddressSanitizer, an address sanity checker.
  10 //
  11 // This file defines things that need to be present in the application modules
  12 // to interact with the ASan DLL runtime correctly and can't be implemented
  13 // using the default "import library" generated when linking the DLL RTL.
  14 //
  15 // This includes:
  16 //  - creating weak aliases to default implementation imported from asan dll.
  17 //  - forwarding the detect_stack_use_after_return runtime option
  18 //  - working around deficiencies of the MD runtime
  19 //  - installing a custom SEH handler
  20 //
  21 //===----------------------------------------------------------------------===//
  22
  23 #ifdef SANITIZER_DYNAMIC_RUNTIME_THUNK
  24 #define SANITIZER_IMPORT_INTERFACE 1
  25 #include "sanitizer_common/sanitizer_win_defs.h"
  26 #define WIN32_LEAN_AND_MEAN
  27 #include <windows.h>
  28
  29 // Define weak alias for all weak functions imported from asan dll.
  30 #define INTERFACE_FUNCTION(Name)
  31 #define INTERFACE_WEAK_FUNCTION(Name) WIN_WEAK_IMPORT_DEF(Name)
  32 #include "asan_interface.inc"
  33
  34 // First, declare CRT sections we'll be using in this file
  35 #pragma section(".CRT$XIB", long, read)
  36 #pragma section(".CRT$XID", long, read)
  37 #pragma section(".CRT$XCAB", long, read)
  38 #pragma section(".CRT$XTW", long, read)
  39 #pragma section(".CRT$XTY", long, read)
  40 #pragma section(".CRT$XLAB", long, read)
  41
  42 ////////////////////////////////////////////////////////////////////////////////
  43 // Define a copy of __asan_option_detect_stack_use_after_return that should be
  44 // used when linking an MD runtime with a set of object files on Windows.
  45 //
  46 // The ASan MD runtime dllexports '__asan_option_detect_stack_use_after_return',
  47 // so normally we would just dllimport it.  Unfortunately, the dllimport
  48 // attribute adds __imp_ prefix to the symbol name of a variable.
  49 // Since in general we don't know if a given TU is going to be used
  50 // with a MT or MD runtime and we don't want to use ugly __imp_ names on Windows
  51 // just to work around this issue, let's clone the variable that is constant
  52 // after initialization anyways.
  53 extern "C" {
  54 __declspec(dllimport) int __asan_should_detect_stack_use_after_return();
  55 int __asan_option_detect_stack_use_after_return;
  56
  57 __declspec(dllimport) void* __asan_get_shadow_memory_dynamic_address();
  58 void* __asan_shadow_memory_dynamic_address;
  59 }
  60
  61 static int InitializeClonedVariables() {
  62   __asan_option_detect_stack_use_after_return =
  63     __asan_should_detect_stack_use_after_return();
  64   __asan_shadow_memory_dynamic_address =
  65     __asan_get_shadow_memory_dynamic_address();
  66   return 0;
  67 }
  68
  69 static void NTAPI asan_thread_init(void *mod, unsigned long reason,
  70     void *reserved) {
  71   if (reason == DLL_PROCESS_ATTACH) InitializeClonedVariables();
  72 }
  73
  74 // Our cloned variables must be initialized before C/C++ constructors.  If TLS
  75 // is used, our .CRT$XLAB initializer will run first. If not, our .CRT$XIB
  76 // initializer is needed as a backup.
  77 __declspec(allocate(".CRT$XIB")) int (*__asan_initialize_cloned_variables)() =
  78     InitializeClonedVariables;
  79 __declspec(allocate(".CRT$XLAB")) void (NTAPI *__asan_tls_init)(void *,
  80     unsigned long, void *) = asan_thread_init;
  81
  82 ////////////////////////////////////////////////////////////////////////////////
  83 // For some reason, the MD CRT doesn't call the C/C++ terminators during on DLL
  84 // unload or on exit.  ASan relies on LLVM global_dtors to call
  85 // __asan_unregister_globals on these events, which unfortunately doesn't work
  86 // with the MD runtime, see PR22545 for the details.
  87 // To work around this, for each DLL we schedule a call to UnregisterGlobals
  88 // using atexit() that calls a small subset of C terminators
  89 // where LLVM global_dtors is placed.  Fingers crossed, no other C terminators
  90 // are there.
  91 extern "C" int __cdecl atexit(void (__cdecl *f)(void));
  92 extern "C" void __cdecl _initterm(void *a, void *b);
  93
  94 namespace {
  95 __declspec(allocate(".CRT$XTW")) void* before_global_dtors = 0;
  96 __declspec(allocate(".CRT$XTY")) void* after_global_dtors = 0;
  97
  98 void UnregisterGlobals() {
  99   _initterm(&before_global_dtors, &after_global_dtors);
 100 }
 101
 102 int ScheduleUnregisterGlobals() {
 103   return atexit(UnregisterGlobals);
 104 }
 105 }  // namespace
 106
 107 // We need to call 'atexit(UnregisterGlobals);' as early as possible, but after
 108 // atexit() is initialized (.CRT$XIC).  As this is executed before C++
 109 // initializers (think ctors for globals), UnregisterGlobals gets executed after
 110 // dtors for C++ globals.
 111 __declspec(allocate(".CRT$XID"))
 112 int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
 113
 114 ////////////////////////////////////////////////////////////////////////////////
 115 // ASan SEH handling.
 116 // We need to set the ASan-specific SEH handler at the end of CRT initialization
 117 // of each module (see also asan_win.cpp).
 118 extern "C" {
 119 __declspec(dllimport) int __asan_set_seh_filter();
 120 static int SetSEHFilter() { return __asan_set_seh_filter(); }
 121
 122 // Unfortunately, putting a pointer to __asan_set_seh_filter into
 123 // __asan_intercept_seh gets optimized out, so we have to use an extra function.
 124 __declspec(allocate(".CRT$XCAB")) int (*__asan_seh_interceptor)() =
 125     SetSEHFilter;
 126 }
 127
 128 WIN_FORCE_LINK(__asan_dso_reg_hook)
 129
 130 #endif // SANITIZER_DYNAMIC_RUNTIME_THUNK