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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 #include "interception/interception.h"
     21 
     22 #include <stddef.h>
     23 
     24 // ---------------------- Replacement functions ---------------- {{{1
     25 using namespace __asan;  // NOLINT
     26 
     27 // FIXME: Simply defining functions with the same signature in *.obj
     28 // files overrides the standard functions in *.lib
     29 // This works well for simple helloworld-like tests but might need to be
     30 // revisited in the future.
     31 
     32 extern "C" {
     33 void free(void *ptr) {
     34   GET_STACK_TRACE_FREE;
     35   return asan_free(ptr, &stack, FROM_MALLOC);
     36 }
     37 
     38 void _free_dbg(void* ptr, int) {
     39   free(ptr);
     40 }
     41 
     42 void cfree(void *ptr) {
     43   CHECK(!"cfree() should not be used on Windows?");
     44 }
     45 
     46 void *malloc(size_t size) {
     47   GET_STACK_TRACE_MALLOC;
     48   return asan_malloc(size, &stack);
     49 }
     50 
     51 void* _malloc_dbg(size_t size, int , const char*, int) {
     52   return malloc(size);
     53 }
     54 
     55 void *calloc(size_t nmemb, size_t size) {
     56   GET_STACK_TRACE_MALLOC;
     57   return asan_calloc(nmemb, size, &stack);
     58 }
     59 
     60 void* _calloc_dbg(size_t n, size_t size, int, const char*, int) {
     61   return calloc(n, size);
     62 }
     63 
     64 void *_calloc_impl(size_t nmemb, size_t size, int *errno_tmp) {
     65   return calloc(nmemb, size);
     66 }
     67 
     68 void *realloc(void *ptr, size_t size) {
     69   GET_STACK_TRACE_MALLOC;
     70   return asan_realloc(ptr, size, &stack);
     71 }
     72 
     73 void *_realloc_dbg(void *ptr, size_t size, int) {
     74   CHECK(!"_realloc_dbg should not exist!");
     75   return 0;
     76 }
     77 
     78 void* _recalloc(void* p, size_t n, size_t elem_size) {
     79   if (!p)
     80     return calloc(n, elem_size);
     81   const size_t size = n * elem_size;
     82   if (elem_size != 0 && size / elem_size != n)
     83     return 0;
     84   return realloc(p, size);
     85 }
     86 
     87 size_t _msize(void *ptr) {
     88   GET_STACK_TRACE_MALLOC;
     89   return asan_malloc_usable_size(ptr, &stack);
     90 }
     91 
     92 int _CrtDbgReport(int, const char*, int,
     93                   const char*, const char*, ...) {
     94   ShowStatsAndAbort();
     95 }
     96 
     97 int _CrtDbgReportW(int reportType, const wchar_t*, int,
     98                    const wchar_t*, const wchar_t*, ...) {
     99   ShowStatsAndAbort();
    100 }
    101 
    102 int _CrtSetReportMode(int, int) {
    103   return 0;
    104 }
    105 }  // extern "C"
    106 
    107 using __interception::GetRealFunctionAddress;
    108 
    109 // We don't want to include "windows.h" in this file to avoid extra attributes
    110 // set on malloc/free etc (e.g. dllimport), so declare a few things manually:
    111 extern "C" int __stdcall VirtualProtect(void* addr, size_t size,
    112                                         DWORD prot, DWORD *old_prot);
    113 const int PAGE_EXECUTE_READWRITE = 0x40;
    114 
    115 namespace __asan {
    116 void ReplaceSystemMalloc() {
    117 #if defined(_DLL)
    118 # ifdef _WIN64
    119 #  error ReplaceSystemMalloc was not tested on x64
    120 # endif
    121   char *crt_malloc;
    122   if (GetRealFunctionAddress("malloc", (void**)&crt_malloc)) {
    123     // Replace malloc in the CRT dll with a jump to our malloc.
    124     DWORD old_prot, unused;
    125     CHECK(VirtualProtect(crt_malloc, 16, PAGE_EXECUTE_READWRITE, &old_prot));
    126     REAL(memset)(crt_malloc, 0xCC /* int 3 */, 16);  // just in case.
    127 
    128     ptrdiff_t jmp_offset = (char*)malloc - (char*)crt_malloc - 5;
    129     crt_malloc[0] = 0xE9;  // jmp, should be followed by an offset.
    130     REAL(memcpy)(crt_malloc + 1, &jmp_offset, sizeof(jmp_offset));
    131 
    132     CHECK(VirtualProtect(crt_malloc, 16, old_prot, &unused));
    133 
    134     // FYI: FlushInstructionCache is needed on Itanium etc but not on x86/x64.
    135   }
    136 
    137   // FIXME: investigate whether anything else is needed.
    138 #endif
    139 }
    140 }  // namespace __asan
    141 
    142 #endif  // _WIN32
    143