1 //===-- interception_linux.cc -----------------------------------*- C++ -*-===//
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
6 //===----------------------------------------------------------------------===//
8 // This file is a part of AddressSanitizer, an address sanity checker.
10 // Windows-specific interception methods.
11 //===----------------------------------------------------------------------===//
15 #include "interception.h"
16 #define WIN32_LEAN_AND_MEAN
19 namespace __interception
{
21 // FIXME: internal_str* and internal_mem* functions should be moved from the
22 // ASan sources into interception/.
24 static void _memset(void *p
, int value
, size_t sz
) {
25 for (size_t i
= 0; i
< sz
; ++i
)
26 ((char*)p
)[i
] = (char)value
;
29 static void _memcpy(void *dst
, void *src
, size_t sz
) {
30 char *dst_c
= (char*)dst
,
32 for (size_t i
= 0; i
< sz
; ++i
)
36 static void WriteJumpInstruction(char *jmp_from
, char *to
) {
37 // jmp XXYYZZWW = E9 WW ZZ YY XX, where XXYYZZWW is an offset fromt jmp_from
38 // to the next instruction to the destination.
39 ptrdiff_t offset
= to
- jmp_from
- 5;
41 *(ptrdiff_t*)(jmp_from
+ 1) = offset
;
44 static char *GetMemoryForTrampoline(size_t size
) {
45 // Trampolines are allocated from a common pool.
46 const int POOL_SIZE
= 1024;
47 static char *pool
= NULL
;
48 static size_t pool_used
= 0;
50 pool
= (char *)VirtualAlloc(NULL
, POOL_SIZE
, MEM_RESERVE
| MEM_COMMIT
,
51 PAGE_EXECUTE_READWRITE
);
52 // FIXME: Might want to apply PAGE_EXECUTE_READ access after all the
53 // interceptors are in place.
56 _memset(pool
, 0xCC /* int 3 */, POOL_SIZE
);
59 if (pool_used
+ size
> POOL_SIZE
)
62 char *ret
= pool
+ pool_used
;
67 // Returns 0 on error.
68 static size_t RoundUpToInstrBoundary(size_t size
, char *code
) {
70 while (cursor
< size
) {
71 switch (code
[cursor
]) {
72 case '\x51': // push ecx
73 case '\x52': // push edx
74 case '\x53': // push ebx
75 case '\x54': // push esp
76 case '\x55': // push ebp
77 case '\x56': // push esi
78 case '\x57': // push edi
79 case '\x5D': // pop ebp
82 case '\x6A': // 6A XX = push XX
85 case '\xE9': // E9 XX YY ZZ WW = jmp WWZZYYXX
86 case '\xB8': // B8 XX YY ZZ WW = mov eax, WWZZYYXX
90 switch (*(unsigned short*)(code
+ cursor
)) { // NOLINT
91 case 0xFF8B: // 8B FF = mov edi, edi
92 case 0xEC8B: // 8B EC = mov ebp, esp
93 case 0xC033: // 33 C0 = xor eax, eax
96 case 0x458B: // 8B 45 XX = mov eax, dword ptr [ebp+XXh]
97 case 0x5D8B: // 8B 5D XX = mov ebx, dword ptr [ebp+XXh]
98 case 0xEC83: // 83 EC XX = sub esp, XX
99 case 0x75FF: // FF 75 XX = push dword ptr [ebp+XXh]
102 case 0xC1F7: // F7 C1 XX YY ZZ WW = test ecx, WWZZYYXX
103 case 0x25FF: // FF 25 XX YY ZZ WW = jmp dword ptr ds:[WWZZYYXX]
106 case 0x3D83: // 83 3D XX YY ZZ WW TT = cmp TT, WWZZYYXX
110 switch (0x00FFFFFF & *(unsigned int*)(code
+ cursor
)) {
111 case 0x24448A: // 8A 44 24 XX = mov eal, dword ptr [esp+XXh]
112 case 0x24448B: // 8B 44 24 XX = mov eax, dword ptr [esp+XXh]
113 case 0x244C8B: // 8B 4C 24 XX = mov ecx, dword ptr [esp+XXh]
114 case 0x24548B: // 8B 54 24 XX = mov edx, dword ptr [esp+XXh]
115 case 0x24748B: // 8B 74 24 XX = mov esi, dword ptr [esp+XXh]
116 case 0x247C8B: // 8B 7C 24 XX = mov edi, dword ptr [esp+XXh]
121 // Unknown instruction!
122 // FIXME: Unknown instruction failures might happen when we add a new
123 // interceptor or a new compiler version. In either case, they should result
124 // in visible and readable error messages. However, merely calling abort()
125 // leads to an infinite recursion in CheckFailed.
126 // Do we have a good way to abort with an error message here?
134 bool OverrideFunction(uptr old_func
, uptr new_func
, uptr
*orig_old_func
) {
136 #error OverrideFunction is not yet supported on x64
138 // Function overriding works basically like this:
139 // We write "jmp <new_func>" (5 bytes) at the beginning of the 'old_func'
141 // We might want to be able to execute the original 'old_func' from the
142 // wrapper, in this case we need to keep the leading 5+ bytes ('head')
143 // of the original code somewhere with a "jmp <old_func+head>".
144 // We call these 'head'+5 bytes of instructions a "trampoline".
145 char *old_bytes
= (char *)old_func
;
147 // We'll need at least 5 bytes for a 'jmp'.
150 // Find out the number of bytes of the instructions we need to copy
151 // to the trampoline and store it in 'head'.
152 head
= RoundUpToInstrBoundary(head
, old_bytes
);
156 // Put the needed instructions into the trampoline bytes.
157 char *trampoline
= GetMemoryForTrampoline(head
+ 5);
160 _memcpy(trampoline
, old_bytes
, head
);
161 WriteJumpInstruction(trampoline
+ head
, old_bytes
+ head
);
162 *orig_old_func
= (uptr
)trampoline
;
165 // Now put the "jmp <new_func>" instruction at the original code location.
166 // We should preserve the EXECUTE flag as some of our own code might be
167 // located in the same page (sic!). FIXME: might consider putting the
168 // __interception code into a separate section or something?
169 DWORD old_prot
, unused_prot
;
170 if (!VirtualProtect((void *)old_bytes
, head
, PAGE_EXECUTE_READWRITE
,
174 WriteJumpInstruction(old_bytes
, (char *)new_func
);
175 _memset(old_bytes
+ 5, 0xCC /* int 3 */, head
- 5);
177 // Restore the original permissions.
178 if (!VirtualProtect((void *)old_bytes
, head
, old_prot
, &unused_prot
))
179 return false; // not clear if this failure bothers us.
184 static void **InterestingDLLsAvailable() {
185 const char *InterestingDLLs
[] = {
187 "msvcr110.dll", // VS2012
188 "msvcr120.dll", // VS2013
189 // NTDLL should go last as it exports some functions that we should override
190 // in the CRT [presumably only used internally].
193 static void *result
[ARRAY_SIZE(InterestingDLLs
)] = { 0 };
195 for (size_t i
= 0, j
= 0; InterestingDLLs
[i
]; ++i
) {
196 if (HMODULE h
= GetModuleHandleA(InterestingDLLs
[i
]))
197 result
[j
++] = (void *)h
;
204 // Utility for reading loaded PE images.
205 template <typename T
> class RVAPtr
{
207 RVAPtr(void *module
, uptr rva
)
208 : ptr_(reinterpret_cast<T
*>(reinterpret_cast<char *>(module
) + rva
)) {}
209 operator T
*() { return ptr_
; }
210 T
*operator->() { return ptr_
; }
211 T
*operator++() { return ++ptr_
; }
218 // Internal implementation of GetProcAddress. At least since Windows 8,
219 // GetProcAddress appears to initialize DLLs before returning function pointers
220 // into them. This is problematic for the sanitizers, because they typically
221 // want to intercept malloc *before* MSVCRT initializes. Our internal
222 // implementation walks the export list manually without doing initialization.
223 uptr
InternalGetProcAddress(void *module
, const char *func_name
) {
224 // Check that the module header is full and present.
225 RVAPtr
<IMAGE_DOS_HEADER
> dos_stub(module
, 0);
226 RVAPtr
<IMAGE_NT_HEADERS
> headers(module
, dos_stub
->e_lfanew
);
227 if (!module
|| dos_stub
->e_magic
!= IMAGE_DOS_SIGNATURE
|| // "MZ"
228 headers
->Signature
!= IMAGE_NT_SIGNATURE
|| // "PE\0\0"
229 headers
->FileHeader
.SizeOfOptionalHeader
<
230 sizeof(IMAGE_OPTIONAL_HEADER
)) {
234 IMAGE_DATA_DIRECTORY
*export_directory
=
235 &headers
->OptionalHeader
.DataDirectory
[IMAGE_DIRECTORY_ENTRY_EXPORT
];
236 RVAPtr
<IMAGE_EXPORT_DIRECTORY
> exports(module
,
237 export_directory
->VirtualAddress
);
238 RVAPtr
<DWORD
> functions(module
, exports
->AddressOfFunctions
);
239 RVAPtr
<DWORD
> names(module
, exports
->AddressOfNames
);
240 RVAPtr
<WORD
> ordinals(module
, exports
->AddressOfNameOrdinals
);
242 for (DWORD i
= 0; i
< exports
->NumberOfNames
; i
++) {
243 RVAPtr
<char> name(module
, names
[i
]);
244 if (!strcmp(func_name
, name
)) {
245 DWORD index
= ordinals
[i
];
246 RVAPtr
<char> func(module
, functions
[index
]);
247 return (uptr
)(char *)func
;
254 static bool GetFunctionAddressInDLLs(const char *func_name
, uptr
*func_addr
) {
256 void **DLLs
= InterestingDLLsAvailable();
257 for (size_t i
= 0; *func_addr
== 0 && DLLs
[i
]; ++i
)
258 *func_addr
= InternalGetProcAddress(DLLs
[i
], func_name
);
259 return (*func_addr
!= 0);
262 bool OverrideFunction(const char *name
, uptr new_func
, uptr
*orig_old_func
) {
264 if (!GetFunctionAddressInDLLs(name
, &orig_func
))
266 return OverrideFunction(orig_func
, new_func
, orig_old_func
);
269 } // namespace __interception