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      1 //===-- asan_malloc_win.cc ------------------------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file is a part of AddressSanitizer, an address sanity checker.
     11 //
     12 // Windows-specific malloc interception.
     13 //===----------------------------------------------------------------------===//
     14 #ifdef _WIN32
     15 
     16 #include "asan_allocator.h"
     17 #include "asan_interceptors.h"
     18 #include "asan_internal.h"
     19 #include "asan_stack.h"
     20 
     21 #include "interception/interception.h"
     22 
     23 // ---------------------- Replacement functions ---------------- {{{1
     24 using namespace __asan;  // NOLINT
     25 
     26 // FIXME: Simply defining functions with the same signature in *.obj
     27 // files overrides the standard functions in *.lib
     28 // This works well for simple helloworld-like tests but might need to be
     29 // revisited in the future.
     30 
     31 extern "C" {
     32 void free(void *ptr) {
     33   GET_STACK_TRACE_HERE_FOR_FREE(ptr);
     34   return asan_free(ptr, &stack);
     35 }
     36 
     37 void _free_dbg(void* ptr, int) {
     38   free(ptr);
     39 }
     40 
     41 void cfree(void *ptr) {
     42   CHECK(!"cfree() should not be used on Windows?");
     43 }
     44 
     45 void *malloc(size_t size) {
     46   GET_STACK_TRACE_HERE_FOR_MALLOC;
     47   return asan_malloc(size, &stack);
     48 }
     49 
     50 void* _malloc_dbg(size_t size, int , const char*, int) {
     51   return malloc(size);
     52 }
     53 
     54 void *calloc(size_t nmemb, size_t size) {
     55   GET_STACK_TRACE_HERE_FOR_MALLOC;
     56   return asan_calloc(nmemb, size, &stack);
     57 }
     58 
     59 void* _calloc_dbg(size_t n, size_t size, int, const char*, int) {
     60   return calloc(n, size);
     61 }
     62 
     63 void *_calloc_impl(size_t nmemb, size_t size, int *errno_tmp) {
     64   return calloc(nmemb, size);
     65 }
     66 
     67 void *realloc(void *ptr, size_t size) {
     68   GET_STACK_TRACE_HERE_FOR_MALLOC;
     69   return asan_realloc(ptr, size, &stack);
     70 }
     71 
     72 void *_realloc_dbg(void *ptr, size_t size, int) {
     73   CHECK(!"_realloc_dbg should not exist!");
     74   return 0;
     75 }
     76 
     77 void* _recalloc(void* p, size_t n, size_t elem_size) {
     78   if (!p)
     79     return calloc(n, elem_size);
     80   const size_t size = n * elem_size;
     81   if (elem_size != 0 && size / elem_size != n)
     82     return 0;
     83   return realloc(p, size);
     84 }
     85 
     86 size_t _msize(void *ptr) {
     87   GET_STACK_TRACE_HERE_FOR_MALLOC;
     88   return asan_malloc_usable_size(ptr, &stack);
     89 }
     90 
     91 int _CrtDbgReport(int, const char*, int,
     92                   const char*, const char*, ...) {
     93   ShowStatsAndAbort();
     94 }
     95 
     96 int _CrtDbgReportW(int reportType, const wchar_t*, int,
     97                    const wchar_t*, const wchar_t*, ...) {
     98   ShowStatsAndAbort();
     99 }
    100 
    101 int _CrtSetReportMode(int, int) {
    102   return 0;
    103 }
    104 }  // extern "C"
    105 
    106 using __interception::GetRealFunctionAddress;
    107 
    108 // We don't want to include "windows.h" in this file to avoid extra attributes
    109 // set on malloc/free etc (e.g. dllimport), so declare a few things manually:
    110 extern "C" int __stdcall VirtualProtect(void* addr, size_t size,
    111                                         DWORD prot, DWORD *old_prot);
    112 const int PAGE_EXECUTE_READWRITE = 0x40;
    113 
    114 namespace __asan {
    115 void ReplaceSystemMalloc() {
    116 #if defined(_DLL)
    117 # ifdef _WIN64
    118 #  error ReplaceSystemMalloc was not tested on x64
    119 # endif
    120   char *crt_malloc;
    121   if (GetRealFunctionAddress("malloc", (void**)&crt_malloc)) {
    122     // Replace malloc in the CRT dll with a jump to our malloc.
    123     DWORD old_prot, unused;
    124     CHECK(VirtualProtect(crt_malloc, 16, PAGE_EXECUTE_READWRITE, &old_prot));
    125     REAL(memset)(crt_malloc, 0xCC /* int 3 */, 16);  // just in case.
    126 
    127     ptrdiff_t jmp_offset = (char*)malloc - (char*)crt_malloc - 5;
    128     crt_malloc[0] = 0xE9;  // jmp, should be followed by an offset.
    129     REAL(memcpy)(crt_malloc + 1, &jmp_offset, sizeof(jmp_offset));
    130 
    131     CHECK(VirtualProtect(crt_malloc, 16, old_prot, &unused));
    132 
    133     // FYI: FlushInstructionCache is needed on Itanium etc but not on x86/x64.
    134   }
    135 
    136   // FIXME: investigate whether anything else is needed.
    137 #endif
    138 }
    139 }  // namespace __asan
    140 
    141 #endif  // _WIN32
    142