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chromium / external / github.com / llvm / llvm-project.git / 868b31bf21b0400383f198b84ddefc6fdc5e6c4a / . / compiler-rt / lib / interception / interception_win.cc
blob: bd4ad7274dded29e139b1ee0aa5f1c4a8591af60 [file] [log] [blame]
Timur Iskhodzhanov36d297d2012-02-22 13:59:49[diff] [blame]1//===-- interception_linux.cc -----------------------------------*- C++ -*-===//
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 interception methods.
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]13//
14// This file is implementing several hooking techniques to intercept calls
15// to functions. The hooks are dynamically installed by modifying the assembly
16// code.
17//
18// The hooking techniques are making assumptions on the way the code is
19// generated and are safe under these assumptions.
20//
21// On 64-bit architecture, there is no direct 64-bit jump instruction. To allow
22// arbitrary branching on the whole memory space, the notion of trampoline
23// region is used. A trampoline region is a memory space withing 2G boundary
24// where it is safe to add custom assembly code to build 64-bit jumps.
25//
26// Hooking techniques
27// ==================
28//
29// 1) Detour
30//
31// The Detour hooking technique is assuming the presence of an header with
32// padding and an overridable 2-bytes nop instruction (mov edi, edi). The
33// nop instruction can safely be replaced by a 2-bytes jump without any need
34// to save the instruction. A jump to the target is encoded in the function
35// header and the nop instruction is replaced by a short jump to the header.
36//
37// head: 5 x nop head: jmp <hook>
38// func: mov edi, edi --> func: jmp short <head>
39// [...] real: [...]
40//
41// This technique is only implemented on 32-bit architecture.
42// Most of the time, Windows API are hookable with the detour technique.
43//
44// 2) Redirect Jump
45//
46// The redirect jump is applicable when the first instruction is a direct
47// jump. The instruction is replaced by jump to the hook.
48//
49// func: jmp <label> --> func: jmp <hook>
50//
51// On an 64-bit architecture, a trampoline is inserted.
52//
53// func: jmp <label> --> func: jmp <tramp>
54// [...]
55//
56// [trampoline]
57// tramp: jmp QWORD [addr]
58// addr: .bytes <hook>
59//
60// Note: <real> is equilavent to <label>.
61//
62// 3) HotPatch
63//
64// The HotPatch hooking is assuming the presence of an header with padding
65// and a first instruction with at least 2-bytes.
66//
67// The reason to enforce the 2-bytes limitation is to provide the minimal
68// space to encode a short jump. HotPatch technique is only rewriting one
69// instruction to avoid breaking a sequence of instructions containing a
70// branching target.
71//
72// Assumptions are enforced by MSVC compiler by using the /HOTPATCH flag.
73// see: https://msdn.microsoft.com/en-us/library/ms173507.aspx
74// Default padding length is 5 bytes in 32-bits and 6 bytes in 64-bits.
75//
76// head: 5 x nop head: jmp <hook>
77// func: <instr> --> func: jmp short <head>
78// [...] body: [...]
79//
80// [trampoline]
81// real: <instr>
82// jmp <body>
83//
84// On an 64-bit architecture:
85//
86// head: 6 x nop head: jmp QWORD [addr1]
87// func: <instr> --> func: jmp short <head>
88// [...] body: [...]
89//
90// [trampoline]
91// addr1: .bytes <hook>
92// real: <instr>
93// jmp QWORD [addr2]
94// addr2: .bytes <body>
95//
96// 4) Trampoline
97//
98// The Trampoline hooking technique is the most aggressive one. It is
99// assuming that there is a sequence of instructions that can be safely
100// replaced by a jump (enough room and no incoming branches).
101//
102// Unfortunately, these assumptions can't be safely presumed and code may
103// be broken after hooking.
104//
105// func: <instr> --> func: jmp <hook>
106// <instr>
107// [...] body: [...]
108//
109// [trampoline]
110// real: <instr>
111// <instr>
112// jmp <body>
113//
114// On an 64-bit architecture:
115//
116// func: <instr> --> func: jmp QWORD [addr1]
117// <instr>
118// [...] body: [...]
119//
120// [trampoline]
121// addr1: .bytes <hook>
122// real: <instr>
123// <instr>
124// jmp QWORD [addr2]
125// addr2: .bytes <body>
Timur Iskhodzhanov36d297d2012-02-22 13:59:49[diff] [blame]126//===----------------------------------------------------------------------===//
127
Alexey Samsonov9d7429502012-08-02 11:29:14[diff] [blame]128#include "interception.h"
Kamil Rytarowski90b46352017-12-06 17:02:00[diff] [blame]129
130#if SANITIZER_WINDOWS
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]131#include "sanitizer_common/sanitizer_platform.h"
Saleem Abdulrasoold006c932015-10-29 20:36:55[diff] [blame]132#define WIN32_LEAN_AND_MEAN
Timur Iskhodzhanov36d297d2012-02-22 13:59:49[diff] [blame]133#include <windows.h>
134
135namespace __interception {
136
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]137static const int kAddressLength = FIRST_32_SECOND_64(4, 8);
138static const int kJumpInstructionLength = 5;
139static const int kShortJumpInstructionLength = 2;
140static const int kIndirectJumpInstructionLength = 6;
141static const int kBranchLength =
142 FIRST_32_SECOND_64(kJumpInstructionLength, kIndirectJumpInstructionLength);
143static const int kDirectBranchLength = kBranchLength + kAddressLength;
144
145static void InterceptionFailed() {
146 // Do we have a good way to abort with an error message here?
147 __debugbreak();
148}
149
150static bool DistanceIsWithin2Gig(uptr from, uptr target) {
Reid Kleckner0d7c42c2016-11-15 18:29:17[diff] [blame]151#if SANITIZER_WINDOWS64
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]152 if (from < target)
153 return target - from <= (uptr)0x7FFFFFFFU;
154 else
155 return from - target <= (uptr)0x80000000U;
Reid Kleckner0d7c42c2016-11-15 18:29:17[diff] [blame]156#else
157 // In a 32-bit address space, the address calculation will wrap, so this check
158 // is unnecessary.
159 return true;
160#endif
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]161}
162
163static uptr GetMmapGranularity() {
164 SYSTEM_INFO si;
165 GetSystemInfo(&si);
166 return si.dwAllocationGranularity;
167}
168
169static uptr RoundUpTo(uptr size, uptr boundary) {
170 return (size + boundary - 1) & ~(boundary - 1);
171}
172
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]173// FIXME: internal_str* and internal_mem* functions should be moved from the
174// ASan sources into interception/.
175
Etienne Bergeron0b2d7132016-07-31 17:56:26[diff] [blame]176static size_t _strlen(const char *str) {
177 const char* p = str;
178 while (*p != '\0') ++p;
179 return p - str;
180}
181
182static char* _strchr(char* str, char c) {
183 while (*str) {
184 if (*str == c)
185 return str;
186 ++str;
187 }
188 return nullptr;
189}
190
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]191static void _memset(void *p, int value, size_t sz) {
192 for (size_t i = 0; i < sz; ++i)
193 ((char*)p)[i] = (char)value;
194}
195
196static void _memcpy(void *dst, void *src, size_t sz) {
197 char *dst_c = (char*)dst,
198 *src_c = (char*)src;
199 for (size_t i = 0; i < sz; ++i)
200 dst_c[i] = src_c[i];
201}
202
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]203static bool ChangeMemoryProtection(
204 uptr address, uptr size, DWORD *old_protection) {
205 return ::VirtualProtect((void*)address, size,
206 PAGE_EXECUTE_READWRITE,
207 old_protection) != FALSE;
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]208}
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]209
210static bool RestoreMemoryProtection(
211 uptr address, uptr size, DWORD old_protection) {
212 DWORD unused;
213 return ::VirtualProtect((void*)address, size,
214 old_protection,
215 &unused) != FALSE;
216}
217
218static bool IsMemoryPadding(uptr address, uptr size) {
219 u8* function = (u8*)address;
220 for (size_t i = 0; i < size; ++i)
221 if (function[i] != 0x90 && function[i] != 0xCC)
222 return false;
223 return true;
224}
225
Reid Klecknerc3fc3bc2017-08-08 21:18:36[diff] [blame]226static const u8 kHintNop9Bytes[] = {
227 0x66, 0x0F, 0x1F, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00
Etienne Bergeron9c2a2202016-07-12 15:33:04[diff] [blame]228};
229
230template<class T>
231static bool FunctionHasPrefix(uptr address, const T &pattern) {
232 u8* function = (u8*)address - sizeof(pattern);
233 for (size_t i = 0; i < sizeof(pattern); ++i)
234 if (function[i] != pattern[i])
235 return false;
236 return true;
237}
238
239static bool FunctionHasPadding(uptr address, uptr size) {
240 if (IsMemoryPadding(address - size, size))
241 return true;
Reid Klecknerc3fc3bc2017-08-08 21:18:36[diff] [blame]242 if (size <= sizeof(kHintNop9Bytes) &&
243 FunctionHasPrefix(address, kHintNop9Bytes))
Etienne Bergeron9c2a2202016-07-12 15:33:04[diff] [blame]244 return true;
245 return false;
246}
247
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]248static void WritePadding(uptr from, uptr size) {
249 _memset((void*)from, 0xCC, (size_t)size);
250}
251
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]252static void WriteJumpInstruction(uptr from, uptr target) {
253 if (!DistanceIsWithin2Gig(from + kJumpInstructionLength, target))
254 InterceptionFailed();
255 ptrdiff_t offset = target - from - kJumpInstructionLength;
256 *(u8*)from = 0xE9;
257 *(u32*)(from + 1) = offset;
258}
259
260static void WriteShortJumpInstruction(uptr from, uptr target) {
261 sptr offset = target - from - kShortJumpInstructionLength;
262 if (offset < -128 || offset > 127)
263 InterceptionFailed();
264 *(u8*)from = 0xEB;
265 *(u8*)(from + 1) = (u8)offset;
266}
267
268#if SANITIZER_WINDOWS64
269static void WriteIndirectJumpInstruction(uptr from, uptr indirect_target) {
270 // jmp [rip + <offset>] = FF 25 <offset> where <offset> is a relative
271 // offset.
272 // The offset is the distance from then end of the jump instruction to the
273 // memory location containing the targeted address. The displacement is still
274 // 32-bit in x64, so indirect_target must be located within +/- 2GB range.
275 int offset = indirect_target - from - kIndirectJumpInstructionLength;
276 if (!DistanceIsWithin2Gig(from + kIndirectJumpInstructionLength,
277 indirect_target)) {
278 InterceptionFailed();
279 }
280 *(u16*)from = 0x25FF;
281 *(u32*)(from + 2) = offset;
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]282}
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]283#endif
284
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]285static void WriteBranch(
286 uptr from, uptr indirect_target, uptr target) {
287#if SANITIZER_WINDOWS64
288 WriteIndirectJumpInstruction(from, indirect_target);
289 *(u64*)indirect_target = target;
290#else
291 (void)indirect_target;
292 WriteJumpInstruction(from, target);
293#endif
294}
295
296static void WriteDirectBranch(uptr from, uptr target) {
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]297#if SANITIZER_WINDOWS64
298 // Emit an indirect jump through immediately following bytes:
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]299 // jmp [rip + kBranchLength]
300 // .quad <target>
301 WriteBranch(from, from + kBranchLength, target);
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]302#else
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]303 WriteJumpInstruction(from, target);
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]304#endif
305}
306
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]307struct TrampolineMemoryRegion {
308 uptr content;
309 uptr allocated_size;
310 uptr max_size;
311};
312
Etienne Bergerond61042b2016-07-18 19:33:05[diff] [blame]313static const uptr kTrampolineScanLimitRange = 1 << 31; // 2 gig
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]314static const int kMaxTrampolineRegion = 1024;
315static TrampolineMemoryRegion TrampolineRegions[kMaxTrampolineRegion];
316
317static void *AllocateTrampolineRegion(uptr image_address, size_t granularity) {
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]318#if SANITIZER_WINDOWS64
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]319 uptr address = image_address;
320 uptr scanned = 0;
321 while (scanned < kTrampolineScanLimitRange) {
322 MEMORY_BASIC_INFORMATION info;
323 if (!::VirtualQuery((void*)address, &info, sizeof(info)))
324 return nullptr;
325
326 // Check whether a region can be allocated at |address|.
327 if (info.State == MEM_FREE && info.RegionSize >= granularity) {
328 void *page = ::VirtualAlloc((void*)RoundUpTo(address, granularity),
329 granularity,
330 MEM_RESERVE | MEM_COMMIT,
331 PAGE_EXECUTE_READWRITE);
332 return page;
333 }
334
335 // Move to the next region.
336 address = (uptr)info.BaseAddress + info.RegionSize;
337 scanned += info.RegionSize;
338 }
339 return nullptr;
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]340#else
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]341 return ::VirtualAlloc(nullptr,
342 granularity,
343 MEM_RESERVE | MEM_COMMIT,
344 PAGE_EXECUTE_READWRITE);
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]345#endif
346}
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]347
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]348// Used by unittests to release mapped memory space.
349void TestOnlyReleaseTrampolineRegions() {
350 for (size_t bucket = 0; bucket < kMaxTrampolineRegion; ++bucket) {
351 TrampolineMemoryRegion *current = &TrampolineRegions[bucket];
352 if (current->content == 0)
353 return;
354 ::VirtualFree((void*)current->content, 0, MEM_RELEASE);
355 current->content = 0;
356 }
357}
358
359static uptr AllocateMemoryForTrampoline(uptr image_address, size_t size) {
360 // Find a region within 2G with enough space to allocate |size| bytes.
361 TrampolineMemoryRegion *region = nullptr;
362 for (size_t bucket = 0; bucket < kMaxTrampolineRegion; ++bucket) {
363 TrampolineMemoryRegion* current = &TrampolineRegions[bucket];
364 if (current->content == 0) {
365 // No valid region found, allocate a new region.
366 size_t bucket_size = GetMmapGranularity();
367 void *content = AllocateTrampolineRegion(image_address, bucket_size);
368 if (content == nullptr)
369 return 0U;
370
371 current->content = (uptr)content;
372 current->allocated_size = 0;
373 current->max_size = bucket_size;
374 region = current;
375 break;
376 } else if (current->max_size - current->allocated_size > size) {
377#if SANITIZER_WINDOWS64
378 // In 64-bits, the memory space must be allocated within 2G boundary.
379 uptr next_address = current->content + current->allocated_size;
380 if (next_address < image_address ||
Etienne Bergeronef4b4492016-07-12 01:30:58[diff] [blame]381 next_address - image_address >= 0x7FFF0000)
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]382 continue;
383#endif
384 // The space can be allocated in the current region.
385 region = current;
386 break;
387 }
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]388 }
389
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]390 // Failed to find a region.
391 if (region == nullptr)
392 return 0U;
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]393
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]394 // Allocate the space in the current region.
395 uptr allocated_space = region->content + region->allocated_size;
396 region->allocated_size += size;
397 WritePadding(allocated_space, size);
398
399 return allocated_space;
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]400}
401
402// Returns 0 on error.
Etienne Bergeron901b0dc2016-07-21 21:08:54[diff] [blame]403static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
Etienne Bergeron8fc1dca2016-07-14 22:14:33[diff] [blame]404 switch (*(u64*)address) {
405 case 0x90909090909006EB: // stub: jmp over 6 x nop.
406 return 8;
407 }
408
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]409 switch (*(u8*)address) {
410 case 0x90: // 90 : nop
411 return 1;
412
413 case 0x50: // push eax / rax
414 case 0x51: // push ecx / rcx
415 case 0x52: // push edx / rdx
416 case 0x53: // push ebx / rbx
417 case 0x54: // push esp / rsp
418 case 0x55: // push ebp / rbp
419 case 0x56: // push esi / rsi
420 case 0x57: // push edi / rdi
421 case 0x5D: // pop ebp / rbp
422 return 1;
423
424 case 0x6A: // 6A XX = push XX
425 return 2;
426
427 case 0xb8: // b8 XX XX XX XX : mov eax, XX XX XX XX
428 case 0xB9: // b9 XX XX XX XX : mov ecx, XX XX XX XX
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]429 return 5;
430
431 // Cannot overwrite control-instruction. Return 0 to indicate failure.
432 case 0xE9: // E9 XX XX XX XX : jmp <label>
433 case 0xE8: // E8 XX XX XX XX : call <func>
434 case 0xC3: // C3 : ret
435 case 0xEB: // EB XX : jmp XX (short jump)
436 case 0x70: // 7Y YY : jy XX (short conditional jump)
437 case 0x71:
438 case 0x72:
439 case 0x73:
440 case 0x74:
441 case 0x75:
442 case 0x76:
443 case 0x77:
444 case 0x78:
445 case 0x79:
446 case 0x7A:
447 case 0x7B:
448 case 0x7C:
449 case 0x7D:
450 case 0x7E:
451 case 0x7F:
452 return 0;
453 }
454
455 switch (*(u16*)(address)) {
David Major868b31b2018-05-11 14:31:14[diff] [blame^]456 case 0x018A: // 8A 01 : mov al, byte ptr [ecx]
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]457 case 0xFF8B: // 8B FF : mov edi, edi
458 case 0xEC8B: // 8B EC : mov ebp, esp
459 case 0xc889: // 89 C8 : mov eax, ecx
460 case 0xC18B: // 8B C1 : mov eax, ecx
461 case 0xC033: // 33 C0 : xor eax, eax
462 case 0xC933: // 33 C9 : xor ecx, ecx
463 case 0xD233: // 33 D2 : xor edx, edx
464 return 2;
465
466 // Cannot overwrite control-instruction. Return 0 to indicate failure.
467 case 0x25FF: // FF 25 XX XX XX XX : jmp [XXXXXXXX]
468 return 0;
469 }
470
Etienne Bergeron2bb23bf2016-08-03 05:03:35[diff] [blame]471 switch (0x00FFFFFF & *(u32*)address) {
472 case 0x24A48D: // 8D A4 24 XX XX XX XX : lea esp, [esp + XX XX XX XX]
473 return 7;
474 }
475
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]476#if SANITIZER_WINDOWS64
Vedant Kumar55ecc102016-07-18 20:07:27[diff] [blame]477 switch (*(u8*)address) {
Etienne Bergerona81a44f2016-07-18 19:50:55[diff] [blame]478 case 0xA1: // A1 XX XX XX XX XX XX XX XX :
479 // movabs eax, dword ptr ds:[XXXXXXXX]
Reid Klecknerf1b9f3a2017-06-16 20:44:00[diff] [blame]480 return 9;
Etienne Bergerona81a44f2016-07-18 19:50:55[diff] [blame]481 }
482
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]483 switch (*(u16*)address) {
484 case 0x5040: // push rax
485 case 0x5140: // push rcx
486 case 0x5240: // push rdx
487 case 0x5340: // push rbx
488 case 0x5440: // push rsp
489 case 0x5540: // push rbp
490 case 0x5640: // push rsi
491 case 0x5740: // push rdi
492 case 0x5441: // push r12
493 case 0x5541: // push r13
494 case 0x5641: // push r14
495 case 0x5741: // push r15
Etienne Bergerone318b832016-07-12 19:39:07[diff] [blame]496 case 0x9066: // Two-byte NOP
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]497 return 2;
Reid Klecknerf1b9f3a2017-06-16 20:44:00[diff] [blame]498
499 case 0x058B: // 8B 05 XX XX XX XX : mov eax, dword ptr [XX XX XX XX]
500 if (rel_offset)
501 *rel_offset = 2;
502 return 6;
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]503 }
504
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]505 switch (0x00FFFFFF & *(u32*)address) {
506 case 0xe58948: // 48 8b c4 : mov rbp, rsp
507 case 0xc18b48: // 48 8b c1 : mov rax, rcx
508 case 0xc48b48: // 48 8b c4 : mov rax, rsp
509 case 0xd9f748: // 48 f7 d9 : neg rcx
510 case 0xd12b48: // 48 2b d1 : sub rdx, rcx
511 case 0x07c1f6: // f6 c1 07 : test cl, 0x7
Etienne Bergeron9f987d32016-09-30 19:37:11[diff] [blame]512 case 0xc98548: // 48 85 C9 : test rcx, rcx
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]513 case 0xc0854d: // 4d 85 c0 : test r8, r8
514 case 0xc2b60f: // 0f b6 c2 : movzx eax, dl
515 case 0xc03345: // 45 33 c0 : xor r8d, r8d
Etienne Bergeron5d427632016-08-02 20:38:05[diff] [blame]516 case 0xdb3345: // 45 33 DB : xor r11d, r11d
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]517 case 0xd98b4c: // 4c 8b d9 : mov r11, rcx
518 case 0xd28b4c: // 4c 8b d2 : mov r10, rdx
Etienne Bergeron5d427632016-08-02 20:38:05[diff] [blame]519 case 0xc98b4c: // 4C 8B C9 : mov r9, rcx
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]520 case 0xd2b60f: // 0f b6 d2 : movzx edx, dl
521 case 0xca2b48: // 48 2b ca : sub rcx, rdx
522 case 0x10b70f: // 0f b7 10 : movzx edx, WORD PTR [rax]
523 case 0xc00b4d: // 3d 0b c0 : or r8, r8
524 case 0xd18b48: // 48 8b d1 : mov rdx, rcx
Etienne Bergeron5d427632016-08-02 20:38:05[diff] [blame]525 case 0xdc8b4c: // 4c 8b dc : mov r11, rsp
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]526 case 0xd18b4c: // 4c 8b d1 : mov r10, rcx
527 return 3;
528
529 case 0xec8348: // 48 83 ec XX : sub rsp, XX
530 case 0xf88349: // 49 83 f8 XX : cmp r8, XX
531 case 0x588948: // 48 89 58 XX : mov QWORD PTR[rax + XX], rbx
532 return 4;
533
Etienne Bergeron5d427632016-08-02 20:38:05[diff] [blame]534 case 0xec8148: // 48 81 EC XX XX XX XX : sub rsp, XXXXXXXX
535 return 7;
536
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]537 case 0x058b48: // 48 8b 05 XX XX XX XX :
538 // mov rax, QWORD PTR [rip + XXXXXXXX]
539 case 0x25ff48: // 48 ff 25 XX XX XX XX :
540 // rex.W jmp QWORD PTR [rip + XXXXXXXX]
Etienne Bergeron901b0dc2016-07-21 21:08:54[diff] [blame]541
542 // Instructions having offset relative to 'rip' need offset adjustment.
543 if (rel_offset)
544 *rel_offset = 3;
545 return 7;
Etienne Bergerona81a44f2016-07-18 19:50:55[diff] [blame]546
547 case 0x2444c7: // C7 44 24 XX YY YY YY YY
548 // mov dword ptr [rsp + XX], YYYYYYYY
549 return 8;
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]550 }
551
552 switch (*(u32*)(address)) {
Etienne Bergeron8fc1dca2016-07-14 22:14:33[diff] [blame]553 case 0x24448b48: // 48 8b 44 24 XX : mov rax, QWORD ptr [rsp + XX]
554 case 0x246c8948: // 48 89 6C 24 XX : mov QWORD ptr [rsp + XX], rbp
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]555 case 0x245c8948: // 48 89 5c 24 XX : mov QWORD PTR [rsp + XX], rbx
556 case 0x24748948: // 48 89 74 24 XX : mov QWORD PTR [rsp + XX], rsi
Reid Kleckner80db37e2017-10-24 18:22:07[diff] [blame]557 case 0x244C8948: // 48 89 4C 24 XX : mov QWORD PTR [rsp + XX], rcx
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]558 return 5;
Reid Kleckner80db37e2017-10-24 18:22:07[diff] [blame]559 case 0x24648348: // 48 83 64 24 XX : and QWORD PTR [rsp + XX], YY
560 return 6;
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]561 }
562
Etienne Bergeron00f3f6e2016-05-27 21:29:31[diff] [blame]563#else
Etienne Bergerona566fe32016-07-15 17:26:33[diff] [blame]564
Etienne Bergerona81a44f2016-07-18 19:50:55[diff] [blame]565 switch (*(u8*)address) {
566 case 0xA1: // A1 XX XX XX XX : mov eax, dword ptr ds:[XXXXXXXX]
567 return 5;
568 }
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]569 switch (*(u16*)address) {
570 case 0x458B: // 8B 45 XX : mov eax, dword ptr [ebp + XX]
571 case 0x5D8B: // 8B 5D XX : mov ebx, dword ptr [ebp + XX]
572 case 0x7D8B: // 8B 7D XX : mov edi, dword ptr [ebp + XX]
573 case 0xEC83: // 83 EC XX : sub esp, XX
574 case 0x75FF: // FF 75 XX : push dword ptr [ebp + XX]
575 return 3;
576 case 0xC1F7: // F7 C1 XX YY ZZ WW : test ecx, WWZZYYXX
577 case 0x25FF: // FF 25 XX YY ZZ WW : jmp dword ptr ds:[WWZZYYXX]
578 return 6;
579 case 0x3D83: // 83 3D XX YY ZZ WW TT : cmp TT, WWZZYYXX
580 return 7;
581 case 0x7D83: // 83 7D XX YY : cmp dword ptr [ebp + XX], YY
582 return 4;
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]583 }
584
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]585 switch (0x00FFFFFF & *(u32*)address) {
586 case 0x24448A: // 8A 44 24 XX : mov eal, dword ptr [esp + XX]
587 case 0x24448B: // 8B 44 24 XX : mov eax, dword ptr [esp + XX]
588 case 0x244C8B: // 8B 4C 24 XX : mov ecx, dword ptr [esp + XX]
589 case 0x24548B: // 8B 54 24 XX : mov edx, dword ptr [esp + XX]
590 case 0x24748B: // 8B 74 24 XX : mov esi, dword ptr [esp + XX]
591 case 0x247C8B: // 8B 7C 24 XX : mov edi, dword ptr [esp + XX]
592 return 4;
593 }
594
595 switch (*(u32*)address) {
596 case 0x2444B60F: // 0F B6 44 24 XX : movzx eax, byte ptr [esp + XX]
597 return 5;
598 }
Etienne Bergeron00f3f6e2016-05-27 21:29:31[diff] [blame]599#endif
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]600
601 // Unknown instruction!
602 // FIXME: Unknown instruction failures might happen when we add a new
603 // interceptor or a new compiler version. In either case, they should result
604 // in visible and readable error messages. However, merely calling abort()
605 // leads to an infinite recursion in CheckFailed.
606 InterceptionFailed();
607 return 0;
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]608}
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]609
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]610// Returns 0 on error.
611static size_t RoundUpToInstrBoundary(size_t size, uptr address) {
612 size_t cursor = 0;
613 while (cursor < size) {
614 size_t instruction_size = GetInstructionSize(address + cursor);
615 if (!instruction_size)
616 return 0;
617 cursor += instruction_size;
618 }
619 return cursor;
620}
621
Etienne Bergeron901b0dc2016-07-21 21:08:54[diff] [blame]622static bool CopyInstructions(uptr to, uptr from, size_t size) {
623 size_t cursor = 0;
624 while (cursor != size) {
625 size_t rel_offset = 0;
626 size_t instruction_size = GetInstructionSize(from + cursor, &rel_offset);
627 _memcpy((void*)(to + cursor), (void*)(from + cursor),
628 (size_t)instruction_size);
629 if (rel_offset) {
630 uptr delta = to - from;
631 uptr relocated_offset = *(u32*)(to + cursor + rel_offset) - delta;
632#if SANITIZER_WINDOWS64
633 if (relocated_offset + 0x80000000U >= 0xFFFFFFFFU)
634 return false;
635#endif
636 *(u32*)(to + cursor + rel_offset) = relocated_offset;
637 }
638 cursor += instruction_size;
639 }
640 return true;
641}
642
643
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]644#if !SANITIZER_WINDOWS64
645bool OverrideFunctionWithDetour(
646 uptr old_func, uptr new_func, uptr *orig_old_func) {
647 const int kDetourHeaderLen = 5;
648 const u16 kDetourInstruction = 0xFF8B;
649
650 uptr header = (uptr)old_func - kDetourHeaderLen;
651 uptr patch_length = kDetourHeaderLen + kShortJumpInstructionLength;
652
653 // Validate that the function is hookable.
654 if (*(u16*)old_func != kDetourInstruction ||
655 !IsMemoryPadding(header, kDetourHeaderLen))
656 return false;
657
658 // Change memory protection to writable.
659 DWORD protection = 0;
660 if (!ChangeMemoryProtection(header, patch_length, &protection))
661 return false;
662
663 // Write a relative jump to the redirected function.
664 WriteJumpInstruction(header, new_func);
665
666 // Write the short jump to the function prefix.
667 WriteShortJumpInstruction(old_func, header);
668
669 // Restore previous memory protection.
670 if (!RestoreMemoryProtection(header, patch_length, protection))
671 return false;
672
673 if (orig_old_func)
674 *orig_old_func = old_func + kShortJumpInstructionLength;
675
676 return true;
677}
678#endif
679
680bool OverrideFunctionWithRedirectJump(
681 uptr old_func, uptr new_func, uptr *orig_old_func) {
682 // Check whether the first instruction is a relative jump.
683 if (*(u8*)old_func != 0xE9)
684 return false;
685
686 if (orig_old_func) {
687 uptr relative_offset = *(u32*)(old_func + 1);
688 uptr absolute_target = old_func + relative_offset + kJumpInstructionLength;
689 *orig_old_func = absolute_target;
690 }
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]691
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]692#if SANITIZER_WINDOWS64
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]693 // If needed, get memory space for a trampoline jump.
694 uptr trampoline = AllocateMemoryForTrampoline(old_func, kDirectBranchLength);
695 if (!trampoline)
696 return false;
697 WriteDirectBranch(trampoline, new_func);
Etienne Bergeron7a1bafd62016-06-06 18:09:54[diff] [blame]698#endif
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]699
700 // Change memory protection to writable.
701 DWORD protection = 0;
702 if (!ChangeMemoryProtection(old_func, kJumpInstructionLength, &protection))
703 return false;
704
705 // Write a relative jump to the redirected function.
706 WriteJumpInstruction(old_func, FIRST_32_SECOND_64(new_func, trampoline));
707
708 // Restore previous memory protection.
709 if (!RestoreMemoryProtection(old_func, kJumpInstructionLength, protection))
710 return false;
711
712 return true;
713}
714
715bool OverrideFunctionWithHotPatch(
716 uptr old_func, uptr new_func, uptr *orig_old_func) {
717 const int kHotPatchHeaderLen = kBranchLength;
718
719 uptr header = (uptr)old_func - kHotPatchHeaderLen;
720 uptr patch_length = kHotPatchHeaderLen + kShortJumpInstructionLength;
721
722 // Validate that the function is hot patchable.
723 size_t instruction_size = GetInstructionSize(old_func);
724 if (instruction_size < kShortJumpInstructionLength ||
Etienne Bergeron9c2a2202016-07-12 15:33:04[diff] [blame]725 !FunctionHasPadding(old_func, kHotPatchHeaderLen))
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]726 return false;
727
728 if (orig_old_func) {
729 // Put the needed instructions into the trampoline bytes.
730 uptr trampoline_length = instruction_size + kDirectBranchLength;
731 uptr trampoline = AllocateMemoryForTrampoline(old_func, trampoline_length);
732 if (!trampoline)
733 return false;
Etienne Bergeron901b0dc2016-07-21 21:08:54[diff] [blame]734 if (!CopyInstructions(trampoline, old_func, instruction_size))
735 return false;
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]736 WriteDirectBranch(trampoline + instruction_size,
737 old_func + instruction_size);
738 *orig_old_func = trampoline;
739 }
740
741 // If needed, get memory space for indirect address.
742 uptr indirect_address = 0;
743#if SANITIZER_WINDOWS64
744 indirect_address = AllocateMemoryForTrampoline(old_func, kAddressLength);
745 if (!indirect_address)
746 return false;
747#endif
748
749 // Change memory protection to writable.
750 DWORD protection = 0;
751 if (!ChangeMemoryProtection(header, patch_length, &protection))
752 return false;
753
754 // Write jumps to the redirected function.
755 WriteBranch(header, indirect_address, new_func);
756 WriteShortJumpInstruction(old_func, header);
757
758 // Restore previous memory protection.
759 if (!RestoreMemoryProtection(header, patch_length, protection))
760 return false;
761
762 return true;
763}
764
765bool OverrideFunctionWithTrampoline(
766 uptr old_func, uptr new_func, uptr *orig_old_func) {
767
768 size_t instructions_length = kBranchLength;
769 size_t padding_length = 0;
770 uptr indirect_address = 0;
771
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]772 if (orig_old_func) {
773 // Find out the number of bytes of the instructions we need to copy
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]774 // to the trampoline.
775 instructions_length = RoundUpToInstrBoundary(kBranchLength, old_func);
776 if (!instructions_length)
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]777 return false;
778
779 // Put the needed instructions into the trampoline bytes.
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]780 uptr trampoline_length = instructions_length + kDirectBranchLength;
781 uptr trampoline = AllocateMemoryForTrampoline(old_func, trampoline_length);
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]782 if (!trampoline)
783 return false;
Etienne Bergeron901b0dc2016-07-21 21:08:54[diff] [blame]784 if (!CopyInstructions(trampoline, old_func, instructions_length))
785 return false;
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]786 WriteDirectBranch(trampoline + instructions_length,
787 old_func + instructions_length);
788 *orig_old_func = trampoline;
Timur Iskhodzhanov37c00b42014-05-16 14:04:57[diff] [blame]789 }
790
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]791#if SANITIZER_WINDOWS64
792 // Check if the targeted address can be encoded in the function padding.
793 // Otherwise, allocate it in the trampoline region.
794 if (IsMemoryPadding(old_func - kAddressLength, kAddressLength)) {
795 indirect_address = old_func - kAddressLength;
796 padding_length = kAddressLength;
797 } else {
798 indirect_address = AllocateMemoryForTrampoline(old_func, kAddressLength);
799 if (!indirect_address)
800 return false;
801 }
802#endif
803
804 // Change memory protection to writable.
805 uptr patch_address = old_func - padding_length;
806 uptr patch_length = instructions_length + padding_length;
807 DWORD protection = 0;
808 if (!ChangeMemoryProtection(patch_address, patch_length, &protection))
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]809 return false;
810
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]811 // Patch the original function.
812 WriteBranch(old_func, indirect_address, new_func);
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]813
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]814 // Restore previous memory protection.
815 if (!RestoreMemoryProtection(patch_address, patch_length, protection))
816 return false;
Timur Iskhodzhanov2f48b872012-03-12 11:45:09[diff] [blame]817
818 return true;
819}
820
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]821bool OverrideFunction(
822 uptr old_func, uptr new_func, uptr *orig_old_func) {
823#if !SANITIZER_WINDOWS64
824 if (OverrideFunctionWithDetour(old_func, new_func, orig_old_func))
825 return true;
826#endif
827 if (OverrideFunctionWithRedirectJump(old_func, new_func, orig_old_func))
828 return true;
829 if (OverrideFunctionWithHotPatch(old_func, new_func, orig_old_func))
830 return true;
831 if (OverrideFunctionWithTrampoline(old_func, new_func, orig_old_func))
832 return true;
833 return false;
834}
835
Reid Klecknerd85f7012015-08-18 22:38:27[diff] [blame]836static void **InterestingDLLsAvailable() {
Etienne Bergeroncc464d52016-07-06 19:15:11[diff] [blame]837 static const char *InterestingDLLs[] = {
Reid Kleckner3b029052016-03-24 20:19:48[diff] [blame]838 "kernel32.dll",
Reid Kleckneraf86cba2017-10-30 17:26:13[diff] [blame]839 "msvcr100.dll", // VS2010
Reid Kleckner3b029052016-03-24 20:19:48[diff] [blame]840 "msvcr110.dll", // VS2012
841 "msvcr120.dll", // VS2013
842 "vcruntime140.dll", // VS2015
843 "ucrtbase.dll", // Universal CRT
844 // NTDLL should go last as it exports some functions that we should
845 // override in the CRT [presumably only used internally].
846 "ntdll.dll", NULL};
Timur Iskhodzhanov0a88b252014-08-25 13:19:05[diff] [blame]847 static void *result[ARRAY_SIZE(InterestingDLLs)] = { 0 };
848 if (!result[0]) {
849 for (size_t i = 0, j = 0; InterestingDLLs[i]; ++i) {
850 if (HMODULE h = GetModuleHandleA(InterestingDLLs[i]))
851 result[j++] = (void *)h;
852 }
853 }
Reid Klecknerd85f7012015-08-18 22:38:27[diff] [blame]854 return &result[0];
855}
856
857namespace {
858// Utility for reading loaded PE images.
859template <typename T> class RVAPtr {
860 public:
861 RVAPtr(void *module, uptr rva)
862 : ptr_(reinterpret_cast<T *>(reinterpret_cast<char *>(module) + rva)) {}
863 operator T *() { return ptr_; }
864 T *operator->() { return ptr_; }
865 T *operator++() { return ++ptr_; }
866
867 private:
868 T *ptr_;
869};
870} // namespace
871
872// Internal implementation of GetProcAddress. At least since Windows 8,
873// GetProcAddress appears to initialize DLLs before returning function pointers
874// into them. This is problematic for the sanitizers, because they typically
875// want to intercept malloc *before* MSVCRT initializes. Our internal
876// implementation walks the export list manually without doing initialization.
877uptr InternalGetProcAddress(void *module, const char *func_name) {
878 // Check that the module header is full and present.
879 RVAPtr<IMAGE_DOS_HEADER> dos_stub(module, 0);
880 RVAPtr<IMAGE_NT_HEADERS> headers(module, dos_stub->e_lfanew);
881 if (!module || dos_stub->e_magic != IMAGE_DOS_SIGNATURE || // "MZ"
882 headers->Signature != IMAGE_NT_SIGNATURE || // "PE\0\0"
883 headers->FileHeader.SizeOfOptionalHeader <
884 sizeof(IMAGE_OPTIONAL_HEADER)) {
885 return 0;
886 }
887
888 IMAGE_DATA_DIRECTORY *export_directory =
889 &headers->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT];
Marcos Pividori7ac943c2017-01-30 18:23:37[diff] [blame]890 if (export_directory->Size == 0)
891 return 0;
Reid Klecknerd85f7012015-08-18 22:38:27[diff] [blame]892 RVAPtr<IMAGE_EXPORT_DIRECTORY> exports(module,
893 export_directory->VirtualAddress);
894 RVAPtr<DWORD> functions(module, exports->AddressOfFunctions);
895 RVAPtr<DWORD> names(module, exports->AddressOfNames);
896 RVAPtr<WORD> ordinals(module, exports->AddressOfNameOrdinals);
897
898 for (DWORD i = 0; i < exports->NumberOfNames; i++) {
899 RVAPtr<char> name(module, names[i]);
900 if (!strcmp(func_name, name)) {
901 DWORD index = ordinals[i];
902 RVAPtr<char> func(module, functions[index]);
Etienne Bergeron0b2d7132016-07-31 17:56:26[diff] [blame]903
904 // Handle forwarded functions.
905 DWORD offset = functions[index];
906 if (offset >= export_directory->VirtualAddress &&
907 offset < export_directory->VirtualAddress + export_directory->Size) {
908 // An entry for a forwarded function is a string with the following
909 // format: "<module> . <function_name>" that is stored into the
910 // exported directory.
911 char function_name[256];
912 size_t funtion_name_length = _strlen(func);
913 if (funtion_name_length >= sizeof(function_name) - 1)
914 InterceptionFailed();
915
916 _memcpy(function_name, func, funtion_name_length);
917 function_name[funtion_name_length] = '\0';
918 char* separator = _strchr(function_name, '.');
919 if (!separator)
920 InterceptionFailed();
921 *separator = '\0';
922
923 void* redirected_module = GetModuleHandleA(function_name);
924 if (!redirected_module)
925 InterceptionFailed();
926 return InternalGetProcAddress(redirected_module, separator + 1);
927 }
928
Reid Klecknerd85f7012015-08-18 22:38:27[diff] [blame]929 return (uptr)(char *)func;
930 }
931 }
932
933 return 0;
Timur Iskhodzhanov0a88b252014-08-25 13:19:05[diff] [blame]934}
935
Etienne Bergeron42cdfbc2016-09-28 18:04:07[diff] [blame]936bool OverrideFunction(
937 const char *func_name, uptr new_func, uptr *orig_old_func) {
938 bool hooked = false;
Reid Klecknerd85f7012015-08-18 22:38:27[diff] [blame]939 void **DLLs = InterestingDLLsAvailable();
Etienne Bergeron42cdfbc2016-09-28 18:04:07[diff] [blame]940 for (size_t i = 0; DLLs[i]; ++i) {
941 uptr func_addr = InternalGetProcAddress(DLLs[i], func_name);
942 if (func_addr &&
943 OverrideFunction(func_addr, new_func, orig_old_func)) {
944 hooked = true;
945 }
946 }
947 return hooked;
Timur Iskhodzhanov0a88b252014-08-25 13:19:05[diff] [blame]948}
949
Reid Kleckner3b029052016-03-24 20:19:48[diff] [blame]950bool OverrideImportedFunction(const char *module_to_patch,
951 const char *imported_module,
952 const char *function_name, uptr new_function,
953 uptr *orig_old_func) {
954 HMODULE module = GetModuleHandleA(module_to_patch);
955 if (!module)
956 return false;
957
958 // Check that the module header is full and present.
959 RVAPtr<IMAGE_DOS_HEADER> dos_stub(module, 0);
960 RVAPtr<IMAGE_NT_HEADERS> headers(module, dos_stub->e_lfanew);
961 if (!module || dos_stub->e_magic != IMAGE_DOS_SIGNATURE || // "MZ"
Etienne Bergeronf5525672016-07-11 23:02:18[diff] [blame]962 headers->Signature != IMAGE_NT_SIGNATURE || // "PE\0\0"
Reid Kleckner3b029052016-03-24 20:19:48[diff] [blame]963 headers->FileHeader.SizeOfOptionalHeader <
964 sizeof(IMAGE_OPTIONAL_HEADER)) {
965 return false;
966 }
967
968 IMAGE_DATA_DIRECTORY *import_directory =
969 &headers->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT];
970
971 // Iterate the list of imported DLLs. FirstThunk will be null for the last
972 // entry.
973 RVAPtr<IMAGE_IMPORT_DESCRIPTOR> imports(module,
974 import_directory->VirtualAddress);
975 for (; imports->FirstThunk != 0; ++imports) {
976 RVAPtr<const char> modname(module, imports->Name);
977 if (_stricmp(&*modname, imported_module) == 0)
978 break;
979 }
980 if (imports->FirstThunk == 0)
981 return false;
982
983 // We have two parallel arrays: the import address table (IAT) and the table
984 // of names. They start out containing the same data, but the loader rewrites
985 // the IAT to hold imported addresses and leaves the name table in
986 // OriginalFirstThunk alone.
987 RVAPtr<IMAGE_THUNK_DATA> name_table(module, imports->OriginalFirstThunk);
988 RVAPtr<IMAGE_THUNK_DATA> iat(module, imports->FirstThunk);
989 for (; name_table->u1.Ordinal != 0; ++name_table, ++iat) {
990 if (!IMAGE_SNAP_BY_ORDINAL(name_table->u1.Ordinal)) {
991 RVAPtr<IMAGE_IMPORT_BY_NAME> import_by_name(
992 module, name_table->u1.ForwarderString);
993 const char *funcname = &import_by_name->Name[0];
994 if (strcmp(funcname, function_name) == 0)
995 break;
996 }
997 }
998 if (name_table->u1.Ordinal == 0)
999 return false;
1000
1001 // Now we have the correct IAT entry. Do the swap. We have to make the page
1002 // read/write first.
1003 if (orig_old_func)
1004 *orig_old_func = iat->u1.AddressOfData;
1005 DWORD old_prot, unused_prot;
1006 if (!VirtualProtect(&iat->u1.AddressOfData, 4, PAGE_EXECUTE_READWRITE,
1007 &old_prot))
1008 return false;
1009 iat->u1.AddressOfData = new_function;
1010 if (!VirtualProtect(&iat->u1.AddressOfData, 4, old_prot, &unused_prot))
1011 return false; // Not clear if this failure bothers us.
1012 return true;
1013}
1014
Timur Iskhodzhanov36d297d2012-02-22 13:59:49[diff] [blame]1015} // namespace __interception
1016
Kamil Rytarowski90b46352017-12-06 17:02:00[diff] [blame]1017#endif // SANITIZER_MAC