1 //===-- asan_malloc_win.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 // Windows-specific malloc interception.
11 //===----------------------------------------------------------------------===//
12 
13 #include "sanitizer_common/sanitizer_platform.h"
14 #if SANITIZER_WINDOWS
15 #define WIN32_LEAN_AND_MEAN
16 #include <windows.h>
17 
18 #include "asan_allocator.h"
19 #include "asan_interceptors.h"
20 #include "asan_internal.h"
21 #include "asan_stack.h"
22 #include "interception/interception.h"
23 
24 #include <stddef.h>
25 
26 using namespace __asan;  // NOLINT
27 
28 // MT: Simply defining functions with the same signature in *.obj
29 // files overrides the standard functions in the CRT.
30 // MD: Memory allocation functions are defined in the CRT .dll,
31 // so we have to intercept them before they are called for the first time.
32 
33 #if ASAN_DYNAMIC
34 # define ALLOCATION_FUNCTION_ATTRIBUTE
35 #else
36 # define ALLOCATION_FUNCTION_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
37 #endif
38 
39 extern "C" {
40 ALLOCATION_FUNCTION_ATTRIBUTE
free(void * ptr)41 void free(void *ptr) {
42   GET_STACK_TRACE_FREE;
43   return asan_free(ptr, &stack, FROM_MALLOC);
44 }
45 
46 ALLOCATION_FUNCTION_ATTRIBUTE
_free_dbg(void * ptr,int)47 void _free_dbg(void *ptr, int) {
48   free(ptr);
49 }
50 
51 ALLOCATION_FUNCTION_ATTRIBUTE
_free_base(void * ptr)52 void _free_base(void *ptr) {
53   free(ptr);
54 }
55 
56 ALLOCATION_FUNCTION_ATTRIBUTE
malloc(size_t size)57 void *malloc(size_t size) {
58   GET_STACK_TRACE_MALLOC;
59   return asan_malloc(size, &stack);
60 }
61 
62 ALLOCATION_FUNCTION_ATTRIBUTE
_malloc_base(size_t size)63 void *_malloc_base(size_t size) {
64   return malloc(size);
65 }
66 
67 ALLOCATION_FUNCTION_ATTRIBUTE
_malloc_dbg(size_t size,int,const char *,int)68 void *_malloc_dbg(size_t size, int, const char *, int) {
69   return malloc(size);
70 }
71 
72 ALLOCATION_FUNCTION_ATTRIBUTE
calloc(size_t nmemb,size_t size)73 void *calloc(size_t nmemb, size_t size) {
74   GET_STACK_TRACE_MALLOC;
75   return asan_calloc(nmemb, size, &stack);
76 }
77 
78 ALLOCATION_FUNCTION_ATTRIBUTE
_calloc_base(size_t nmemb,size_t size)79 void *_calloc_base(size_t nmemb, size_t size) {
80   return calloc(nmemb, size);
81 }
82 
83 ALLOCATION_FUNCTION_ATTRIBUTE
_calloc_dbg(size_t nmemb,size_t size,int,const char *,int)84 void *_calloc_dbg(size_t nmemb, size_t size, int, const char *, int) {
85   return calloc(nmemb, size);
86 }
87 
88 ALLOCATION_FUNCTION_ATTRIBUTE
_calloc_impl(size_t nmemb,size_t size,int * errno_tmp)89 void *_calloc_impl(size_t nmemb, size_t size, int *errno_tmp) {
90   return calloc(nmemb, size);
91 }
92 
93 ALLOCATION_FUNCTION_ATTRIBUTE
realloc(void * ptr,size_t size)94 void *realloc(void *ptr, size_t size) {
95   GET_STACK_TRACE_MALLOC;
96   return asan_realloc(ptr, size, &stack);
97 }
98 
99 ALLOCATION_FUNCTION_ATTRIBUTE
_realloc_dbg(void * ptr,size_t size,int)100 void *_realloc_dbg(void *ptr, size_t size, int) {
101   UNREACHABLE("_realloc_dbg should not exist!");
102   return 0;
103 }
104 
105 ALLOCATION_FUNCTION_ATTRIBUTE
_realloc_base(void * ptr,size_t size)106 void *_realloc_base(void *ptr, size_t size) {
107   return realloc(ptr, size);
108 }
109 
110 ALLOCATION_FUNCTION_ATTRIBUTE
_recalloc(void * p,size_t n,size_t elem_size)111 void *_recalloc(void *p, size_t n, size_t elem_size) {
112   if (!p)
113     return calloc(n, elem_size);
114   const size_t size = n * elem_size;
115   if (elem_size != 0 && size / elem_size != n)
116     return 0;
117   return realloc(p, size);
118 }
119 
120 ALLOCATION_FUNCTION_ATTRIBUTE
_recalloc_base(void * p,size_t n,size_t elem_size)121 void *_recalloc_base(void *p, size_t n, size_t elem_size) {
122   return _recalloc(p, n, elem_size);
123 }
124 
125 ALLOCATION_FUNCTION_ATTRIBUTE
_msize(const void * ptr)126 size_t _msize(const void *ptr) {
127   GET_CURRENT_PC_BP_SP;
128   (void)sp;
129   return asan_malloc_usable_size(ptr, pc, bp);
130 }
131 
132 ALLOCATION_FUNCTION_ATTRIBUTE
_expand(void * memblock,size_t size)133 void *_expand(void *memblock, size_t size) {
134   // _expand is used in realloc-like functions to resize the buffer if possible.
135   // We don't want memory to stand still while resizing buffers, so return 0.
136   return 0;
137 }
138 
139 ALLOCATION_FUNCTION_ATTRIBUTE
_expand_dbg(void * memblock,size_t size)140 void *_expand_dbg(void *memblock, size_t size) {
141   return _expand(memblock, size);
142 }
143 
144 // TODO(timurrrr): Might want to add support for _aligned_* allocation
145 // functions to detect a bit more bugs.  Those functions seem to wrap malloc().
146 
_CrtDbgReport(int,const char *,int,const char *,const char *,...)147 int _CrtDbgReport(int, const char*, int,
148                   const char*, const char*, ...) {
149   ShowStatsAndAbort();
150 }
151 
_CrtDbgReportW(int reportType,const wchar_t *,int,const wchar_t *,const wchar_t *,...)152 int _CrtDbgReportW(int reportType, const wchar_t*, int,
153                    const wchar_t*, const wchar_t*, ...) {
154   ShowStatsAndAbort();
155 }
156 
_CrtSetReportMode(int,int)157 int _CrtSetReportMode(int, int) {
158   return 0;
159 }
160 }  // extern "C"
161 
INTERCEPTOR_WINAPI(LPVOID,HeapAlloc,HANDLE hHeap,DWORD dwFlags,SIZE_T dwBytes)162 INTERCEPTOR_WINAPI(LPVOID, HeapAlloc, HANDLE hHeap, DWORD dwFlags,
163                    SIZE_T dwBytes) {
164   GET_STACK_TRACE_MALLOC;
165   void *p = asan_malloc(dwBytes, &stack);
166   // Reading MSDN suggests that the *entire* usable allocation is zeroed out.
167   // Otherwise it is difficult to HeapReAlloc with HEAP_ZERO_MEMORY.
168   // https://blogs.msdn.microsoft.com/oldnewthing/20120316-00/?p=8083
169   if (dwFlags == HEAP_ZERO_MEMORY)
170     internal_memset(p, 0, asan_mz_size(p));
171   else
172     CHECK(dwFlags == 0 && "unsupported heap flags");
173   return p;
174 }
175 
INTERCEPTOR_WINAPI(BOOL,HeapFree,HANDLE hHeap,DWORD dwFlags,LPVOID lpMem)176 INTERCEPTOR_WINAPI(BOOL, HeapFree, HANDLE hHeap, DWORD dwFlags, LPVOID lpMem) {
177   CHECK(dwFlags == 0 && "unsupported heap flags");
178   GET_STACK_TRACE_FREE;
179   asan_free(lpMem, &stack, FROM_MALLOC);
180   return true;
181 }
182 
INTERCEPTOR_WINAPI(LPVOID,HeapReAlloc,HANDLE hHeap,DWORD dwFlags,LPVOID lpMem,SIZE_T dwBytes)183 INTERCEPTOR_WINAPI(LPVOID, HeapReAlloc, HANDLE hHeap, DWORD dwFlags,
184                    LPVOID lpMem, SIZE_T dwBytes) {
185   GET_STACK_TRACE_MALLOC;
186   // Realloc should never reallocate in place.
187   if (dwFlags & HEAP_REALLOC_IN_PLACE_ONLY)
188     return nullptr;
189   CHECK(dwFlags == 0 && "unsupported heap flags");
190   return asan_realloc(lpMem, dwBytes, &stack);
191 }
192 
INTERCEPTOR_WINAPI(SIZE_T,HeapSize,HANDLE hHeap,DWORD dwFlags,LPCVOID lpMem)193 INTERCEPTOR_WINAPI(SIZE_T, HeapSize, HANDLE hHeap, DWORD dwFlags,
194                    LPCVOID lpMem) {
195   CHECK(dwFlags == 0 && "unsupported heap flags");
196   GET_CURRENT_PC_BP_SP;
197   (void)sp;
198   return asan_malloc_usable_size(lpMem, pc, bp);
199 }
200 
201 namespace __asan {
202 
TryToOverrideFunction(const char * fname,uptr new_func)203 static void TryToOverrideFunction(const char *fname, uptr new_func) {
204   // Failure here is not fatal. The CRT may not be present, and different CRT
205   // versions use different symbols.
206   if (!__interception::OverrideFunction(fname, new_func))
207     VPrintf(2, "Failed to override function %s\n", fname);
208 }
209 
ReplaceSystemMalloc()210 void ReplaceSystemMalloc() {
211 #if defined(ASAN_DYNAMIC)
212   TryToOverrideFunction("free", (uptr)free);
213   TryToOverrideFunction("_free_base", (uptr)free);
214   TryToOverrideFunction("malloc", (uptr)malloc);
215   TryToOverrideFunction("_malloc_base", (uptr)malloc);
216   TryToOverrideFunction("_malloc_crt", (uptr)malloc);
217   TryToOverrideFunction("calloc", (uptr)calloc);
218   TryToOverrideFunction("_calloc_base", (uptr)calloc);
219   TryToOverrideFunction("_calloc_crt", (uptr)calloc);
220   TryToOverrideFunction("realloc", (uptr)realloc);
221   TryToOverrideFunction("_realloc_base", (uptr)realloc);
222   TryToOverrideFunction("_realloc_crt", (uptr)realloc);
223   TryToOverrideFunction("_recalloc", (uptr)_recalloc);
224   TryToOverrideFunction("_recalloc_base", (uptr)_recalloc);
225   TryToOverrideFunction("_recalloc_crt", (uptr)_recalloc);
226   TryToOverrideFunction("_msize", (uptr)_msize);
227   TryToOverrideFunction("_expand", (uptr)_expand);
228   TryToOverrideFunction("_expand_base", (uptr)_expand);
229 
230   // Recent versions of ucrtbase.dll appear to be built with PGO and LTCG, which
231   // enable cross-module inlining. This means our _malloc_base hook won't catch
232   // all CRT allocations. This code here patches the import table of
233   // ucrtbase.dll so that all attempts to use the lower-level win32 heap
234   // allocation API will be directed to ASan's heap. We don't currently
235   // intercept all calls to HeapAlloc. If we did, we would have to check on
236   // HeapFree whether the pointer came from ASan of from the system.
237 #define INTERCEPT_UCRT_FUNCTION(func)                                         \
238   if (!INTERCEPT_FUNCTION_DLLIMPORT("ucrtbase.dll",                           \
239                                     "api-ms-win-core-heap-l1-1-0.dll", func)) \
240     VPrintf(2, "Failed to intercept ucrtbase.dll import %s\n", #func);
241   INTERCEPT_UCRT_FUNCTION(HeapAlloc);
242   INTERCEPT_UCRT_FUNCTION(HeapFree);
243   INTERCEPT_UCRT_FUNCTION(HeapReAlloc);
244   INTERCEPT_UCRT_FUNCTION(HeapSize);
245 #undef INTERCEPT_UCRT_FUNCTION
246 #endif
247 }
248 }  // namespace __asan
249 
250 #endif  // _WIN32
251