1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
|
//===-- interception_win.cpp ------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Windows-specific interception methods.
//
// This file is implementing several hooking techniques to intercept calls
// to functions. The hooks are dynamically installed by modifying the assembly
// code.
//
// The hooking techniques are making assumptions on the way the code is
// generated and are safe under these assumptions.
//
// On 64-bit architecture, there is no direct 64-bit jump instruction. To allow
// arbitrary branching on the whole memory space, the notion of trampoline
// region is used. A trampoline region is a memory space withing 2G boundary
// where it is safe to add custom assembly code to build 64-bit jumps.
//
// Hooking techniques
// ==================
//
// 1) Detour
//
// The Detour hooking technique is assuming the presence of a header with
// padding and an overridable 2-bytes nop instruction (mov edi, edi). The
// nop instruction can safely be replaced by a 2-bytes jump without any need
// to save the instruction. A jump to the target is encoded in the function
// header and the nop instruction is replaced by a short jump to the header.
//
// head: 5 x nop head: jmp <hook>
// func: mov edi, edi --> func: jmp short <head>
// [...] real: [...]
//
// This technique is only implemented on 32-bit architecture.
// Most of the time, Windows API are hookable with the detour technique.
//
// 2) Redirect Jump
//
// The redirect jump is applicable when the first instruction is a direct
// jump. The instruction is replaced by jump to the hook.
//
// func: jmp <label> --> func: jmp <hook>
//
// On a 64-bit architecture, a trampoline is inserted.
//
// func: jmp <label> --> func: jmp <tramp>
// [...]
//
// [trampoline]
// tramp: jmp QWORD [addr]
// addr: .bytes <hook>
//
// Note: <real> is equivalent to <label>.
//
// 3) HotPatch
//
// The HotPatch hooking is assuming the presence of a header with padding
// and a first instruction with at least 2-bytes.
//
// The reason to enforce the 2-bytes limitation is to provide the minimal
// space to encode a short jump. HotPatch technique is only rewriting one
// instruction to avoid breaking a sequence of instructions containing a
// branching target.
//
// Assumptions are enforced by MSVC compiler by using the /HOTPATCH flag.
// see: https://msdn.microsoft.com/en-us/library/ms173507.aspx
// Default padding length is 5 bytes in 32-bits and 6 bytes in 64-bits.
//
// head: 5 x nop head: jmp <hook>
// func: <instr> --> func: jmp short <head>
// [...] body: [...]
//
// [trampoline]
// real: <instr>
// jmp <body>
//
// On a 64-bit architecture:
//
// head: 6 x nop head: jmp QWORD [addr1]
// func: <instr> --> func: jmp short <head>
// [...] body: [...]
//
// [trampoline]
// addr1: .bytes <hook>
// real: <instr>
// jmp QWORD [addr2]
// addr2: .bytes <body>
//
// 4) Trampoline
//
// The Trampoline hooking technique is the most aggressive one. It is
// assuming that there is a sequence of instructions that can be safely
// replaced by a jump (enough room and no incoming branches).
//
// Unfortunately, these assumptions can't be safely presumed and code may
// be broken after hooking.
//
// func: <instr> --> func: jmp <hook>
// <instr>
// [...] body: [...]
//
// [trampoline]
// real: <instr>
// <instr>
// jmp <body>
//
// On a 64-bit architecture:
//
// func: <instr> --> func: jmp QWORD [addr1]
// <instr>
// [...] body: [...]
//
// [trampoline]
// addr1: .bytes <hook>
// real: <instr>
// <instr>
// jmp QWORD [addr2]
// addr2: .bytes <body>
//===----------------------------------------------------------------------===//
#include "interception.h"
#if SANITIZER_WINDOWS
#include "sanitizer_common/sanitizer_platform.h"
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <psapi.h>
namespace __interception {
static const int kAddressLength = FIRST_32_SECOND_64(4, 8);
static const int kJumpInstructionLength = 5;
static const int kShortJumpInstructionLength = 2;
UNUSED static const int kIndirectJumpInstructionLength = 6;
static const int kBranchLength =
FIRST_32_SECOND_64(kJumpInstructionLength, kIndirectJumpInstructionLength);
static const int kDirectBranchLength = kBranchLength + kAddressLength;
# if defined(_MSC_VER)
# define INTERCEPTION_FORMAT(f, a)
# else
# define INTERCEPTION_FORMAT(f, a) __attribute__((format(printf, f, a)))
# endif
static void (*ErrorReportCallback)(const char *format, ...)
INTERCEPTION_FORMAT(1, 2);
void SetErrorReportCallback(void (*callback)(const char *format, ...)) {
ErrorReportCallback = callback;
}
# define ReportError(...) \
do { \
if (ErrorReportCallback) \
ErrorReportCallback(__VA_ARGS__); \
} while (0)
static void InterceptionFailed() {
ReportError("interception_win: failed due to an unrecoverable error.\n");
// This acts like an abort when no debugger is attached. According to an old
// comment, calling abort() leads to an infinite recursion in CheckFailed.
__debugbreak();
}
static bool DistanceIsWithin2Gig(uptr from, uptr target) {
#if SANITIZER_WINDOWS64
if (from < target)
return target - from <= (uptr)0x7FFFFFFFU;
else
return from - target <= (uptr)0x80000000U;
#else
// In a 32-bit address space, the address calculation will wrap, so this check
// is unnecessary.
return true;
#endif
}
static uptr GetMmapGranularity() {
SYSTEM_INFO si;
GetSystemInfo(&si);
return si.dwAllocationGranularity;
}
UNUSED static uptr RoundDownTo(uptr size, uptr boundary) {
return size & ~(boundary - 1);
}
UNUSED static uptr RoundUpTo(uptr size, uptr boundary) {
return RoundDownTo(size + boundary - 1, boundary);
}
// FIXME: internal_str* and internal_mem* functions should be moved from the
// ASan sources into interception/.
static size_t _strlen(const char *str) {
const char* p = str;
while (*p != '\0') ++p;
return p - str;
}
static char* _strchr(char* str, char c) {
while (*str) {
if (*str == c)
return str;
++str;
}
return nullptr;
}
static int _strcmp(const char *s1, const char *s2) {
while (true) {
unsigned c1 = *s1;
unsigned c2 = *s2;
if (c1 != c2) return (c1 < c2) ? -1 : 1;
if (c1 == 0) break;
s1++;
s2++;
}
return 0;
}
static void _memset(void *p, int value, size_t sz) {
for (size_t i = 0; i < sz; ++i)
((char*)p)[i] = (char)value;
}
static void _memcpy(void *dst, void *src, size_t sz) {
char *dst_c = (char*)dst,
*src_c = (char*)src;
for (size_t i = 0; i < sz; ++i)
dst_c[i] = src_c[i];
}
static bool ChangeMemoryProtection(
uptr address, uptr size, DWORD *old_protection) {
return ::VirtualProtect((void*)address, size,
PAGE_EXECUTE_READWRITE,
old_protection) != FALSE;
}
static bool RestoreMemoryProtection(
uptr address, uptr size, DWORD old_protection) {
DWORD unused;
return ::VirtualProtect((void*)address, size,
old_protection,
&unused) != FALSE;
}
static bool IsMemoryPadding(uptr address, uptr size) {
u8* function = (u8*)address;
for (size_t i = 0; i < size; ++i)
if (function[i] != 0x90 && function[i] != 0xCC)
return false;
return true;
}
static const u8 kHintNop8Bytes[] = {
0x0F, 0x1F, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00
};
template<class T>
static bool FunctionHasPrefix(uptr address, const T &pattern) {
u8* function = (u8*)address - sizeof(pattern);
for (size_t i = 0; i < sizeof(pattern); ++i)
if (function[i] != pattern[i])
return false;
return true;
}
static bool FunctionHasPadding(uptr address, uptr size) {
if (IsMemoryPadding(address - size, size))
return true;
if (size <= sizeof(kHintNop8Bytes) &&
FunctionHasPrefix(address, kHintNop8Bytes))
return true;
return false;
}
static void WritePadding(uptr from, uptr size) {
_memset((void*)from, 0xCC, (size_t)size);
}
static void WriteJumpInstruction(uptr from, uptr target) {
if (!DistanceIsWithin2Gig(from + kJumpInstructionLength, target)) {
ReportError(
"interception_win: cannot write jmp further than 2GB away, from %p to "
"%p.\n",
(void *)from, (void *)target);
InterceptionFailed();
}
ptrdiff_t offset = target - from - kJumpInstructionLength;
*(u8*)from = 0xE9;
*(u32*)(from + 1) = offset;
}
static void WriteShortJumpInstruction(uptr from, uptr target) {
sptr offset = target - from - kShortJumpInstructionLength;
if (offset < -128 || offset > 127) {
ReportError("interception_win: cannot write short jmp from %p to %p\n",
(void *)from, (void *)target);
InterceptionFailed();
}
*(u8*)from = 0xEB;
*(u8*)(from + 1) = (u8)offset;
}
#if SANITIZER_WINDOWS64
static void WriteIndirectJumpInstruction(uptr from, uptr indirect_target) {
// jmp [rip + <offset>] = FF 25 <offset> where <offset> is a relative
// offset.
// The offset is the distance from then end of the jump instruction to the
// memory location containing the targeted address. The displacement is still
// 32-bit in x64, so indirect_target must be located within +/- 2GB range.
int offset = indirect_target - from - kIndirectJumpInstructionLength;
if (!DistanceIsWithin2Gig(from + kIndirectJumpInstructionLength,
indirect_target)) {
ReportError(
"interception_win: cannot write indirect jmp with target further than "
"2GB away, from %p to %p.\n",
(void *)from, (void *)indirect_target);
InterceptionFailed();
}
*(u16*)from = 0x25FF;
*(u32*)(from + 2) = offset;
}
#endif
static void WriteBranch(
uptr from, uptr indirect_target, uptr target) {
#if SANITIZER_WINDOWS64
WriteIndirectJumpInstruction(from, indirect_target);
*(u64*)indirect_target = target;
#else
(void)indirect_target;
WriteJumpInstruction(from, target);
#endif
}
static void WriteDirectBranch(uptr from, uptr target) {
#if SANITIZER_WINDOWS64
// Emit an indirect jump through immediately following bytes:
// jmp [rip + kBranchLength]
// .quad <target>
WriteBranch(from, from + kBranchLength, target);
#else
WriteJumpInstruction(from, target);
#endif
}
struct TrampolineMemoryRegion {
uptr content;
uptr allocated_size;
uptr max_size;
};
UNUSED static const uptr kTrampolineRangeLimit = 1ull << 31; // 2 gig
static const int kMaxTrampolineRegion = 1024;
static TrampolineMemoryRegion TrampolineRegions[kMaxTrampolineRegion];
static void *AllocateTrampolineRegion(uptr min_addr, uptr max_addr,
uptr func_addr, size_t granularity) {
# if SANITIZER_WINDOWS64
// Clamp {min,max}_addr to the accessible address space.
SYSTEM_INFO system_info;
::GetSystemInfo(&system_info);
uptr min_virtual_addr =
RoundUpTo((uptr)system_info.lpMinimumApplicationAddress, granularity);
uptr max_virtual_addr =
RoundDownTo((uptr)system_info.lpMaximumApplicationAddress, granularity);
if (min_addr < min_virtual_addr)
min_addr = min_virtual_addr;
if (max_addr > max_virtual_addr)
max_addr = max_virtual_addr;
// This loop probes the virtual address space to find free memory in the
// [min_addr, max_addr] interval. The search starts from func_addr and
// proceeds "outwards" towards the interval bounds using two probes, lo_addr
// and hi_addr, for addresses lower/higher than func_addr. At each step, it
// considers the probe closest to func_addr. If that address is not free, the
// probe is advanced (lower or higher depending on the probe) to the next
// memory block and the search continues.
uptr lo_addr = RoundDownTo(func_addr, granularity);
uptr hi_addr = RoundUpTo(func_addr, granularity);
while (lo_addr >= min_addr || hi_addr <= max_addr) {
// Consider the in-range address closest to func_addr.
uptr addr;
if (lo_addr < min_addr)
addr = hi_addr;
else if (hi_addr > max_addr)
addr = lo_addr;
else
addr = (hi_addr - func_addr < func_addr - lo_addr) ? hi_addr : lo_addr;
MEMORY_BASIC_INFORMATION info;
if (!::VirtualQuery((void *)addr, &info, sizeof(info))) {
ReportError(
"interception_win: VirtualQuery in AllocateTrampolineRegion failed "
"for %p\n",
(void *)addr);
return nullptr;
}
// Check whether a region can be allocated at |addr|.
if (info.State == MEM_FREE && info.RegionSize >= granularity) {
void *page =
::VirtualAlloc((void *)addr, granularity, MEM_RESERVE | MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
if (page == nullptr)
ReportError(
"interception_win: VirtualAlloc in AllocateTrampolineRegion failed "
"for %p\n",
(void *)addr);
return page;
}
if (addr == lo_addr)
lo_addr =
RoundDownTo((uptr)info.AllocationBase - granularity, granularity);
if (addr == hi_addr)
hi_addr =
RoundUpTo((uptr)info.BaseAddress + info.RegionSize, granularity);
}
ReportError(
"interception_win: AllocateTrampolineRegion failed to find free memory; "
"min_addr: %p, max_addr: %p, func_addr: %p, granularity: %zu\n",
(void *)min_addr, (void *)max_addr, (void *)func_addr, granularity);
return nullptr;
#else
return ::VirtualAlloc(nullptr,
granularity,
MEM_RESERVE | MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
#endif
}
// Used by unittests to release mapped memory space.
void TestOnlyReleaseTrampolineRegions() {
for (size_t bucket = 0; bucket < kMaxTrampolineRegion; ++bucket) {
TrampolineMemoryRegion *current = &TrampolineRegions[bucket];
if (current->content == 0)
return;
::VirtualFree((void*)current->content, 0, MEM_RELEASE);
current->content = 0;
}
}
static uptr AllocateMemoryForTrampoline(uptr func_address, size_t size) {
# if SANITIZER_WINDOWS64
uptr min_addr = func_address - kTrampolineRangeLimit;
uptr max_addr = func_address + kTrampolineRangeLimit - size;
// Allocate memory within 2GB of the module (DLL or EXE file) so that any
// address within the module can be referenced with PC-relative operands.
// This allows us to not just jump to the trampoline with a PC-relative
// offset, but to relocate any instructions that we copy to the trampoline
// which have references to the original module. If we can't find the base
// address of the module (e.g. if func_address is in mmap'ed memory), just
// stay within 2GB of func_address.
HMODULE module;
if (::GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
(LPCWSTR)func_address, &module)) {
MODULEINFO module_info;
if (::GetModuleInformation(::GetCurrentProcess(), module,
&module_info, sizeof(module_info))) {
min_addr = (uptr)module_info.lpBaseOfDll + module_info.SizeOfImage -
kTrampolineRangeLimit;
max_addr = (uptr)module_info.lpBaseOfDll + kTrampolineRangeLimit - size;
}
}
// Check for overflow.
if (min_addr > func_address)
min_addr = 0;
if (max_addr < func_address)
max_addr = ~(uptr)0;
# else
uptr min_addr = 0;
uptr max_addr = ~min_addr;
# endif
// Find a region within [min_addr,max_addr] with enough space to allocate
// |size| bytes.
TrampolineMemoryRegion *region = nullptr;
for (size_t bucket = 0; bucket < kMaxTrampolineRegion; ++bucket) {
TrampolineMemoryRegion* current = &TrampolineRegions[bucket];
if (current->content == 0) {
// No valid region found, allocate a new region.
size_t bucket_size = GetMmapGranularity();
void *content = AllocateTrampolineRegion(min_addr, max_addr, func_address,
bucket_size);
if (content == nullptr)
return 0U;
current->content = (uptr)content;
current->allocated_size = 0;
current->max_size = bucket_size;
region = current;
break;
} else if (current->max_size - current->allocated_size > size) {
uptr next_address = current->content + current->allocated_size;
if (next_address < min_addr || next_address > max_addr)
continue;
// The space can be allocated in the current region.
region = current;
break;
}
}
// Failed to find a region.
if (region == nullptr)
return 0U;
// Allocate the space in the current region.
uptr allocated_space = region->content + region->allocated_size;
region->allocated_size += size;
WritePadding(allocated_space, size);
return allocated_space;
}
// The following prologues cannot be patched because of the short jump
// jumping to the patching region.
// Short jump patterns below are only for x86_64.
# if SANITIZER_WINDOWS_x64
// ntdll!wcslen in Win11
// 488bc1 mov rax,rcx
// 0fb710 movzx edx,word ptr [rax]
// 4883c002 add rax,2
// 6685d2 test dx,dx
// 75f4 jne -12
static const u8 kPrologueWithShortJump1[] = {
0x48, 0x8b, 0xc1, 0x0f, 0xb7, 0x10, 0x48, 0x83,
0xc0, 0x02, 0x66, 0x85, 0xd2, 0x75, 0xf4,
};
// ntdll!strrchr in Win11
// 4c8bc1 mov r8,rcx
// 8a01 mov al,byte ptr [rcx]
// 48ffc1 inc rcx
// 84c0 test al,al
// 75f7 jne -9
static const u8 kPrologueWithShortJump2[] = {
0x4c, 0x8b, 0xc1, 0x8a, 0x01, 0x48, 0xff, 0xc1,
0x84, 0xc0, 0x75, 0xf7,
};
#endif
// Returns 0 on error.
static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
if (rel_offset) {
*rel_offset = 0;
}
#if SANITIZER_ARM64
// An ARM64 instruction is 4 bytes long.
return 4;
#endif
# if SANITIZER_WINDOWS_x64
if (memcmp((u8*)address, kPrologueWithShortJump1,
sizeof(kPrologueWithShortJump1)) == 0 ||
memcmp((u8*)address, kPrologueWithShortJump2,
sizeof(kPrologueWithShortJump2)) == 0) {
return 0;
}
#endif
switch (*(u64*)address) {
case 0x90909090909006EB: // stub: jmp over 6 x nop.
return 8;
}
switch (*(u8*)address) {
case 0x90: // 90 : nop
case 0xC3: // C3 : ret (for small/empty function interception
case 0xCC: // CC : int 3 i.e. registering weak functions)
return 1;
case 0x50: // push eax / rax
case 0x51: // push ecx / rcx
case 0x52: // push edx / rdx
case 0x53: // push ebx / rbx
case 0x54: // push esp / rsp
case 0x55: // push ebp / rbp
case 0x56: // push esi / rsi
case 0x57: // push edi / rdi
case 0x5D: // pop ebp / rbp
return 1;
case 0x6A: // 6A XX = push XX
return 2;
// This instruction can be encoded with a 16-bit immediate but that is
// incredibly unlikely.
case 0x68: // 68 XX XX XX XX : push imm32
return 5;
case 0xb8: // b8 XX XX XX XX : mov eax, XX XX XX XX
case 0xB9: // b9 XX XX XX XX : mov ecx, XX XX XX XX
case 0xBA: // ba XX XX XX XX : mov edx, XX XX XX XX
return 5;
// Cannot overwrite control-instruction. Return 0 to indicate failure.
case 0xE9: // E9 XX XX XX XX : jmp <label>
case 0xE8: // E8 XX XX XX XX : call <func>
case 0xEB: // EB XX : jmp XX (short jump)
case 0x70: // 7Y YY : jy XX (short conditional jump)
case 0x71:
case 0x72:
case 0x73:
case 0x74:
case 0x75:
case 0x76:
case 0x77:
case 0x78:
case 0x79:
case 0x7A:
case 0x7B:
case 0x7C:
case 0x7D:
case 0x7E:
case 0x7F:
return 0;
}
switch (*(u16*)(address)) {
case 0x018A: // 8A 01 : mov al, byte ptr [ecx]
case 0xFF8B: // 8B FF : mov edi, edi
case 0xEC8B: // 8B EC : mov ebp, esp
case 0xc889: // 89 C8 : mov eax, ecx
case 0xD189: // 89 D1 : mov ecx, edx
case 0xE589: // 89 E5 : mov ebp, esp
case 0xC18B: // 8B C1 : mov eax, ecx
case 0xC031: // 31 C0 : xor eax, eax
case 0xC931: // 31 C9 : xor ecx, ecx
case 0xD231: // 31 D2 : xor edx, edx
case 0xC033: // 33 C0 : xor eax, eax
case 0xC933: // 33 C9 : xor ecx, ecx
case 0xD233: // 33 D2 : xor edx, edx
case 0x9066: // 66 90 : xchg %ax,%ax (Two-byte NOP)
case 0xDB84: // 84 DB : test bl,bl
case 0xC084: // 84 C0 : test al,al
case 0xC984: // 84 C9 : test cl,cl
case 0xD284: // 84 D2 : test dl,dl
return 2;
case 0x3980: // 80 39 XX : cmp BYTE PTR [rcx], XX
case 0x4D8B: // 8B 4D XX : mov XX(%ebp), ecx
case 0x558B: // 8B 55 XX : mov XX(%ebp), edx
case 0x758B: // 8B 75 XX : mov XX(%ebp), esp
case 0xE483: // 83 E4 XX : and esp, XX
case 0xEC83: // 83 EC XX : sub esp, XX
case 0xC1F6: // F6 C1 XX : test cl, XX
return 3;
case 0x89FF: // FF 89 XX XX XX XX : dec dword ptr [ecx + XX XX XX XX]
case 0xEC81: // 81 EC XX XX XX XX : sub esp, XX XX XX XX
return 6;
// Cannot overwrite control-instruction. Return 0 to indicate failure.
case 0x25FF: // FF 25 XX YY ZZ WW : jmp dword ptr ds:[WWZZYYXX]
return 0;
}
switch (0x00FFFFFF & *(u32 *)address) {
case 0x244C8D: // 8D 4C 24 XX : lea ecx, [esp + XX]
case 0x2474FF: // FF 74 24 XX : push qword ptr [rsp + XX]
return 4;
case 0x24A48D: // 8D A4 24 XX XX XX XX : lea esp, [esp + XX XX XX XX]
return 7;
}
switch (0x000000FF & *(u32 *)address) {
case 0xc2: // C2 XX XX : ret XX (needed for registering weak functions)
return 3;
}
# if SANITIZER_WINDOWS_x64
switch (*(u8*)address) {
case 0xA1: // A1 XX XX XX XX XX XX XX XX :
// movabs eax, dword ptr ds:[XXXXXXXX]
return 9;
case 0xF2:
switch (*(u32 *)(address + 1)) {
case 0x2444110f: // f2 0f 11 44 24 XX movsd QWORD PTR
// [rsp + XX], xmm0
case 0x244c110f: // f2 0f 11 4c 24 XX movsd QWORD PTR
// [rsp + XX], xmm1
case 0x2454110f: // f2 0f 11 54 24 XX movsd QWORD PTR
// [rsp + XX], xmm2
case 0x245c110f: // f2 0f 11 5c 24 XX movsd QWORD PTR
// [rsp + XX], xmm3
case 0x2464110f: // f2 0f 11 64 24 XX movsd QWORD PTR
// [rsp + XX], xmm4
return 6;
}
break;
case 0x83:
const u8 next_byte = *(u8*)(address + 1);
const u8 mod = next_byte >> 6;
const u8 rm = next_byte & 7;
if (mod == 1 && rm == 4)
return 5; // 83 ModR/M SIB Disp8 Imm8
// add|or|adc|sbb|and|sub|xor|cmp [r+disp8], imm8
}
switch (*(u16*)address) {
case 0x5040: // push rax
case 0x5140: // push rcx
case 0x5240: // push rdx
case 0x5340: // push rbx
case 0x5440: // push rsp
case 0x5540: // push rbp
case 0x5640: // push rsi
case 0x5740: // push rdi
case 0x5441: // push r12
case 0x5541: // push r13
case 0x5641: // push r14
case 0x5741: // push r15
case 0xc084: // test al, al
case 0x018a: // mov al, byte ptr [rcx]
return 2;
case 0x7E80: // 80 7E YY XX cmp BYTE PTR [rsi+YY], XX
case 0x7D80: // 80 7D YY XX cmp BYTE PTR [rbp+YY], XX
case 0x7A80: // 80 7A YY XX cmp BYTE PTR [rdx+YY], XX
case 0x7880: // 80 78 YY XX cmp BYTE PTR [rax+YY], XX
case 0x7B80: // 80 7B YY XX cmp BYTE PTR [rbx+YY], XX
case 0x7980: // 80 79 YY XX cmp BYTE ptr [rcx+YY], XX
return 4;
case 0x058A: // 8A 05 XX XX XX XX : mov al, byte ptr [XX XX XX XX]
case 0x058B: // 8B 05 XX XX XX XX : mov eax, dword ptr [XX XX XX XX]
if (rel_offset)
*rel_offset = 2;
FALLTHROUGH;
case 0xB841: // 41 B8 XX XX XX XX : mov r8d, XX XX XX XX
return 6;
case 0x7E81: // 81 7E YY XX XX XX XX cmp DWORD PTR [rsi+YY], XX XX XX XX
case 0x7D81: // 81 7D YY XX XX XX XX cmp DWORD PTR [rbp+YY], XX XX XX XX
case 0x7A81: // 81 7A YY XX XX XX XX cmp DWORD PTR [rdx+YY], XX XX XX XX
case 0x7881: // 81 78 YY XX XX XX XX cmp DWORD PTR [rax+YY], XX XX XX XX
case 0x7B81: // 81 7B YY XX XX XX XX cmp DWORD PTR [rbx+YY], XX XX XX XX
case 0x7981: // 81 79 YY XX XX XX XX cmp dword ptr [rcx+YY], XX XX XX XX
return 7;
case 0xb848: // 48 b8 XX XX XX XX XX XX XX XX :
// movabsq XX XX XX XX XX XX XX XX, rax
case 0xba48: // 48 ba XX XX XX XX XX XX XX XX :
// movabsq XX XX XX XX XX XX XX XX, rdx
return 10;
}
switch (0x00FFFFFF & *(u32 *)address) {
case 0x10b70f: // 0f b7 10 : movzx edx, WORD PTR [rax]
case 0xc00b4d: // 4d 0b c0 : or r8, r8
case 0xc03345: // 45 33 c0 : xor r8d, r8d
case 0xc08548: // 48 85 c0 : test rax, rax
case 0xc0854d: // 4d 85 c0 : test r8, r8
case 0xc08b41: // 41 8b c0 : mov eax, r8d
case 0xc0ff48: // 48 ff c0 : inc rax
case 0xc0ff49: // 49 ff c0 : inc r8
case 0xc18b41: // 41 8b c1 : mov eax, r9d
case 0xc18b48: // 48 8b c1 : mov rax, rcx
case 0xc18b4c: // 4c 8b c1 : mov r8, rcx
case 0xc1ff48: // 48 ff c1 : inc rcx
case 0xc1ff49: // 49 ff c1 : inc r9
case 0xc28b41: // 41 8b c2 : mov eax, r10d
case 0x01b60f: // 0f b6 01 : movzx eax, BYTE PTR [rcx]
case 0x09b60f: // 0f b6 09 : movzx ecx, BYTE PTR [rcx]
case 0x11b60f: // 0f b6 11 : movzx edx, BYTE PTR [rcx]
case 0xc2b60f: // 0f b6 c2 : movzx eax, dl
case 0xc2ff48: // 48 ff c2 : inc rdx
case 0xc2ff49: // 49 ff c2 : inc r10
case 0xc38b41: // 41 8b c3 : mov eax, r11d
case 0xc3ff48: // 48 ff c3 : inc rbx
case 0xc3ff49: // 49 ff c3 : inc r11
case 0xc48b41: // 41 8b c4 : mov eax, r12d
case 0xc48b48: // 48 8b c4 : mov rax, rsp
case 0xc4ff49: // 49 ff c4 : inc r12
case 0xc5ff49: // 49 ff c5 : inc r13
case 0xc6ff48: // 48 ff c6 : inc rsi
case 0xc6ff49: // 49 ff c6 : inc r14
case 0xc7ff48: // 48 ff c7 : inc rdi
case 0xc7ff49: // 49 ff c7 : inc r15
case 0xc93345: // 45 33 c9 : xor r9d, r9d
case 0xc98548: // 48 85 c9 : test rcx, rcx
case 0xc9854d: // 4d 85 c9 : test r9, r9
case 0xc98b4c: // 4c 8b c9 : mov r9, rcx
case 0xd12948: // 48 29 d1 : sub rcx, rdx
case 0xca2b48: // 48 2b ca : sub rcx, rdx
case 0xca3b48: // 48 3b ca : cmp rcx, rdx
case 0xd12b48: // 48 2b d1 : sub rdx, rcx
case 0xd18b48: // 48 8b d1 : mov rdx, rcx
case 0xd18b4c: // 4c 8b d1 : mov r10, rcx
case 0xd28548: // 48 85 d2 : test rdx, rdx
case 0xd2854d: // 4d 85 d2 : test r10, r10
case 0xd28b4c: // 4c 8b d2 : mov r10, rdx
case 0xd2b60f: // 0f b6 d2 : movzx edx, dl
case 0xd2be0f: // 0f be d2 : movsx edx, dl
case 0xd98b4c: // 4c 8b d9 : mov r11, rcx
case 0xd9f748: // 48 f7 d9 : neg rcx
case 0xc03145: // 45 31 c0 : xor r8d,r8d
case 0xc93145: // 45 31 c9 : xor r9d,r9d
case 0xdb3345: // 45 33 db : xor r11d, r11d
case 0xc08445: // 45 84 c0 : test r8b,r8b
case 0xd28445: // 45 84 d2 : test r10b,r10b
case 0xdb8548: // 48 85 db : test rbx, rbx
case 0xdb854d: // 4d 85 db : test r11, r11
case 0xdc8b4c: // 4c 8b dc : mov r11, rsp
case 0xe48548: // 48 85 e4 : test rsp, rsp
case 0xe4854d: // 4d 85 e4 : test r12, r12
case 0xc88948: // 48 89 c8 : mov rax,rcx
case 0xcb8948: // 48 89 cb : mov rbx,rcx
case 0xd08948: // 48 89 d0 : mov rax,rdx
case 0xd18948: // 48 89 d1 : mov rcx,rdx
case 0xd38948: // 48 89 d3 : mov rbx,rdx
case 0xe58948: // 48 89 e5 : mov rbp, rsp
case 0xed8548: // 48 85 ed : test rbp, rbp
case 0xc88949: // 49 89 c8 : mov r8, rcx
case 0xc98949: // 49 89 c9 : mov r9, rcx
case 0xca8949: // 49 89 ca : mov r10,rcx
case 0xd08949: // 49 89 d0 : mov r8, rdx
case 0xd18949: // 49 89 d1 : mov r9, rdx
case 0xd28949: // 49 89 d2 : mov r10, rdx
case 0xd38949: // 49 89 d3 : mov r11, rdx
case 0xed854d: // 4d 85 ed : test r13, r13
case 0xf6854d: // 4d 85 f6 : test r14, r14
case 0xff854d: // 4d 85 ff : test r15, r15
return 3;
case 0x245489: // 89 54 24 XX : mov DWORD PTR[rsp + XX], edx
case 0x428d44: // 44 8d 42 XX : lea r8d , [rdx + XX]
case 0x588948: // 48 89 58 XX : mov QWORD PTR[rax + XX], rbx
case 0xec8348: // 48 83 ec XX : sub rsp, XX
case 0xf88349: // 49 83 f8 XX : cmp r8, XX
case 0x488d49: // 49 8d 48 XX : lea rcx, [...]
case 0x048d4c: // 4c 8d 04 XX : lea r8, [...]
case 0x148d4e: // 4e 8d 14 XX : lea r10, [...]
case 0x398366: // 66 83 39 XX : cmp WORD PTR [rcx], XX
return 4;
case 0x441F0F: // 0F 1F 44 XX XX : nop DWORD PTR [...]
case 0x246483: // 83 64 24 XX YY : and DWORD PTR [rsp+XX], YY
return 5;
case 0x788166: // 66 81 78 XX YY YY cmp WORD PTR [rax+XX], YY YY
case 0x798166: // 66 81 79 XX YY YY cmp WORD PTR [rcx+XX], YY YY
case 0x7a8166: // 66 81 7a XX YY YY cmp WORD PTR [rdx+XX], YY YY
case 0x7b8166: // 66 81 7b XX YY YY cmp WORD PTR [rbx+XX], YY YY
case 0x7e8166: // 66 81 7e XX YY YY cmp WORD PTR [rsi+XX], YY YY
case 0x7f8166: // 66 81 7f XX YY YY cmp WORD PTR [rdi+XX], YY YY
return 6;
case 0xec8148: // 48 81 EC XX XX XX XX : sub rsp, XXXXXXXX
case 0xc0c748: // 48 C7 C0 XX XX XX XX : mov rax, XX XX XX XX
return 7;
// clang-format off
case 0x788141: // 41 81 78 XX YY YY YY YY : cmp DWORD PTR [r8+YY], XX XX XX XX
case 0x798141: // 41 81 79 XX YY YY YY YY : cmp DWORD PTR [r9+YY], XX XX XX XX
case 0x7a8141: // 41 81 7a XX YY YY YY YY : cmp DWORD PTR [r10+YY], XX XX XX XX
case 0x7b8141: // 41 81 7b XX YY YY YY YY : cmp DWORD PTR [r11+YY], XX XX XX XX
case 0x7d8141: // 41 81 7d XX YY YY YY YY : cmp DWORD PTR [r13+YY], XX XX XX XX
case 0x7e8141: // 41 81 7e XX YY YY YY YY : cmp DWORD PTR [r14+YY], XX XX XX XX
case 0x7f8141: // 41 81 7f YY XX XX XX XX : cmp DWORD PTR [r15+YY], XX XX XX XX
case 0x247c81: // 81 7c 24 YY XX XX XX XX : cmp DWORD PTR [rsp+YY], XX XX XX XX
return 8;
// clang-format on
case 0x058b48: // 48 8b 05 XX XX XX XX :
// mov rax, QWORD PTR [rip + XXXXXXXX]
case 0x058d48: // 48 8d 05 XX XX XX XX :
// lea rax, QWORD PTR [rip + XXXXXXXX]
case 0x0d8948: // 48 89 0d XX XX XX XX :
// mov QWORD PTR [rip + XXXXXXXX], rcx
case 0x158948: // 48 89 15 XX XX XX XX :
// mov QWORD PTR [rip + XXXXXXXX], rdx
case 0x25ff48: // 48 ff 25 XX XX XX XX :
// rex.W jmp QWORD PTR [rip + XXXXXXXX]
case 0x158D4C: // 4c 8d 15 XX XX XX XX : lea r10, [rip + XX]
// Instructions having offset relative to 'rip' need offset adjustment.
if (rel_offset)
*rel_offset = 3;
return 7;
case 0x2444c7: // C7 44 24 XX YY YY YY YY
// mov dword ptr [rsp + XX], YYYYYYYY
return 8;
case 0x7c8141: // 41 81 7c ZZ YY XX XX XX XX
// cmp DWORD PTR [reg+reg*n+YY], XX XX XX XX
return 9;
}
switch (*(u32*)(address)) {
case 0x01b60f44: // 44 0f b6 01 : movzx r8d, BYTE PTR [rcx]
case 0x09b60f44: // 44 0f b6 09 : movzx r9d, BYTE PTR [rcx]
case 0x0ab60f44: // 44 0f b6 0a : movzx r8d, BYTE PTR [rdx]
case 0x11b60f44: // 44 0f b6 11 : movzx r10d, BYTE PTR [rcx]
case 0x1ab60f44: // 44 0f b6 1a : movzx r11d, BYTE PTR [rdx]
return 4;
case 0x24448b48: // 48 8b 44 24 XX : mov rax, QWORD ptr [rsp + XX]
case 0x246c8948: // 48 89 6C 24 XX : mov QWORD ptr [rsp + XX], rbp
case 0x245c8948: // 48 89 5c 24 XX : mov QWORD PTR [rsp + XX], rbx
case 0x24748948: // 48 89 74 24 XX : mov QWORD PTR [rsp + XX], rsi
case 0x247c8948: // 48 89 7c 24 XX : mov QWORD PTR [rsp + XX], rdi
case 0x244C8948: // 48 89 4C 24 XX : mov QWORD PTR [rsp + XX], rcx
case 0x24548948: // 48 89 54 24 XX : mov QWORD PTR [rsp + XX], rdx
case 0x244c894c: // 4c 89 4c 24 XX : mov QWORD PTR [rsp + XX], r9
case 0x2444894c: // 4c 89 44 24 XX : mov QWORD PTR [rsp + XX], r8
case 0x244c8944: // 44 89 4c 24 XX mov DWORD PTR [rsp + XX], r9d
case 0x24448944: // 44 89 44 24 XX mov DWORD PTR [rsp + XX], r8d
case 0x246c8d48: // 48 8d 6c 24 XX : lea rbp, [rsp + XX]
return 5;
case 0x24648348: // 48 83 64 24 XX YY : and QWORD PTR [rsp + XX], YY
return 6;
case 0x24A48D48: // 48 8D A4 24 XX XX XX XX : lea rsp, [rsp + XX XX XX XX]
return 8;
}
switch (0xFFFFFFFFFFULL & *(u64 *)(address)) {
case 0xC07E0F4866: // 66 48 0F 7E C0 : movq rax, xmm0
return 5;
}
#else
switch (*(u8*)address) {
case 0xA1: // A1 XX XX XX XX : mov eax, dword ptr ds:[XXXXXXXX]
return 5;
}
switch (*(u16*)address) {
case 0x458B: // 8B 45 XX : mov eax, dword ptr [ebp + XX]
case 0x5D8B: // 8B 5D XX : mov ebx, dword ptr [ebp + XX]
case 0x7D8B: // 8B 7D XX : mov edi, dword ptr [ebp + XX]
case 0x758B: // 8B 75 XX : mov esi, dword ptr [ebp + XX]
case 0x75FF: // FF 75 XX : push dword ptr [ebp + XX]
return 3;
case 0xC1F7: // F7 C1 XX YY ZZ WW : test ecx, WWZZYYXX
return 6;
case 0x3D83: // 83 3D XX YY ZZ WW TT : cmp TT, WWZZYYXX
return 7;
case 0x7D83: // 83 7D XX YY : cmp dword ptr [ebp + XX], YY
return 4;
}
switch (0x00FFFFFF & *(u32*)address) {
case 0x24448A: // 8A 44 24 XX : mov eal, dword ptr [esp + XX]
case 0x24448B: // 8B 44 24 XX : mov eax, dword ptr [esp + XX]
case 0x244C8B: // 8B 4C 24 XX : mov ecx, dword ptr [esp + XX]
case 0x24548B: // 8B 54 24 XX : mov edx, dword ptr [esp + XX]
case 0x245C8B: // 8B 5C 24 XX : mov ebx, dword ptr [esp + XX]
case 0x246C8B: // 8B 6C 24 XX : mov ebp, dword ptr [esp + XX]
case 0x24748B: // 8B 74 24 XX : mov esi, dword ptr [esp + XX]
case 0x247C8B: // 8B 7C 24 XX : mov edi, dword ptr [esp + XX]
return 4;
}
switch (*(u32*)address) {
case 0x2444B60F: // 0F B6 44 24 XX : movzx eax, byte ptr [esp + XX]
return 5;
}
#endif
// Unknown instruction! This might happen when we add a new interceptor, use
// a new compiler version, or if Windows changed how some functions are
// compiled. In either case, we print the address and 8 bytes of instructions
// to notify the user about the error and to help identify the unknown
// instruction. Don't treat this as a fatal error, though we can break the
// debugger if one has been attached.
u8 *bytes = (u8 *)address;
ReportError(
"interception_win: unhandled instruction at %p: %02x %02x %02x %02x %02x "
"%02x %02x %02x\n",
(void *)address, bytes[0], bytes[1], bytes[2], bytes[3], bytes[4],
bytes[5], bytes[6], bytes[7]);
if (::IsDebuggerPresent())
__debugbreak();
return 0;
}
size_t TestOnlyGetInstructionSize(uptr address, size_t *rel_offset) {
return GetInstructionSize(address, rel_offset);
}
// Returns 0 on error.
static size_t RoundUpToInstrBoundary(size_t size, uptr address) {
size_t cursor = 0;
while (cursor < size) {
size_t instruction_size = GetInstructionSize(address + cursor);
if (!instruction_size)
return 0;
cursor += instruction_size;
}
return cursor;
}
static bool CopyInstructions(uptr to, uptr from, size_t size) {
size_t cursor = 0;
while (cursor != size) {
size_t rel_offset = 0;
size_t instruction_size = GetInstructionSize(from + cursor, &rel_offset);
if (!instruction_size)
return false;
_memcpy((void *)(to + cursor), (void *)(from + cursor),
(size_t)instruction_size);
if (rel_offset) {
# if SANITIZER_WINDOWS64
// we want to make sure that the new relative offset still fits in 32-bits
// this will be untrue if relocated_offset \notin [-2**31, 2**31)
s64 delta = to - from;
s64 relocated_offset = *(s32 *)(to + cursor + rel_offset) - delta;
if (-0x8000'0000ll > relocated_offset ||
relocated_offset > 0x7FFF'FFFFll) {
ReportError(
"interception_win: CopyInstructions relocated_offset %lld outside "
"32-bit range\n",
(long long)relocated_offset);
return false;
}
# else
// on 32-bit, the relative offset will always be correct
s32 delta = to - from;
s32 relocated_offset = *(s32 *)(to + cursor + rel_offset) - delta;
# endif
*(s32 *)(to + cursor + rel_offset) = relocated_offset;
}
cursor += instruction_size;
}
return true;
}
#if !SANITIZER_WINDOWS64
bool OverrideFunctionWithDetour(
uptr old_func, uptr new_func, uptr *orig_old_func) {
const int kDetourHeaderLen = 5;
const u16 kDetourInstruction = 0xFF8B;
uptr header = (uptr)old_func - kDetourHeaderLen;
uptr patch_length = kDetourHeaderLen + kShortJumpInstructionLength;
// Validate that the function is hookable.
if (*(u16*)old_func != kDetourInstruction ||
!IsMemoryPadding(header, kDetourHeaderLen))
return false;
// Change memory protection to writable.
DWORD protection = 0;
if (!ChangeMemoryProtection(header, patch_length, &protection))
return false;
// Write a relative jump to the redirected function.
WriteJumpInstruction(header, new_func);
// Write the short jump to the function prefix.
WriteShortJumpInstruction(old_func, header);
// Restore previous memory protection.
if (!RestoreMemoryProtection(header, patch_length, protection))
return false;
if (orig_old_func)
*orig_old_func = old_func + kShortJumpInstructionLength;
return true;
}
#endif
bool OverrideFunctionWithRedirectJump(
uptr old_func, uptr new_func, uptr *orig_old_func) {
// Check whether the first instruction is a relative jump.
if (*(u8*)old_func != 0xE9)
return false;
if (orig_old_func) {
sptr relative_offset = *(s32 *)(old_func + 1);
uptr absolute_target = old_func + relative_offset + kJumpInstructionLength;
*orig_old_func = absolute_target;
}
#if SANITIZER_WINDOWS64
// If needed, get memory space for a trampoline jump.
uptr trampoline = AllocateMemoryForTrampoline(old_func, kDirectBranchLength);
if (!trampoline)
return false;
WriteDirectBranch(trampoline, new_func);
#endif
// Change memory protection to writable.
DWORD protection = 0;
if (!ChangeMemoryProtection(old_func, kJumpInstructionLength, &protection))
return false;
// Write a relative jump to the redirected function.
WriteJumpInstruction(old_func, FIRST_32_SECOND_64(new_func, trampoline));
// Restore previous memory protection.
if (!RestoreMemoryProtection(old_func, kJumpInstructionLength, protection))
return false;
return true;
}
bool OverrideFunctionWithHotPatch(
uptr old_func, uptr new_func, uptr *orig_old_func) {
const int kHotPatchHeaderLen = kBranchLength;
uptr header = (uptr)old_func - kHotPatchHeaderLen;
uptr patch_length = kHotPatchHeaderLen + kShortJumpInstructionLength;
// Validate that the function is hot patchable.
size_t instruction_size = GetInstructionSize(old_func);
if (instruction_size < kShortJumpInstructionLength ||
!FunctionHasPadding(old_func, kHotPatchHeaderLen))
return false;
if (orig_old_func) {
// Put the needed instructions into the trampoline bytes.
uptr trampoline_length = instruction_size + kDirectBranchLength;
uptr trampoline = AllocateMemoryForTrampoline(old_func, trampoline_length);
if (!trampoline)
return false;
if (!CopyInstructions(trampoline, old_func, instruction_size))
return false;
WriteDirectBranch(trampoline + instruction_size,
old_func + instruction_size);
*orig_old_func = trampoline;
}
// If needed, get memory space for indirect address.
uptr indirect_address = 0;
#if SANITIZER_WINDOWS64
indirect_address = AllocateMemoryForTrampoline(old_func, kAddressLength);
if (!indirect_address)
return false;
#endif
// Change memory protection to writable.
DWORD protection = 0;
if (!ChangeMemoryProtection(header, patch_length, &protection))
return false;
// Write jumps to the redirected function.
WriteBranch(header, indirect_address, new_func);
WriteShortJumpInstruction(old_func, header);
// Restore previous memory protection.
if (!RestoreMemoryProtection(header, patch_length, protection))
return false;
return true;
}
bool OverrideFunctionWithTrampoline(
uptr old_func, uptr new_func, uptr *orig_old_func) {
size_t instructions_length = kBranchLength;
size_t padding_length = 0;
uptr indirect_address = 0;
if (orig_old_func) {
// Find out the number of bytes of the instructions we need to copy
// to the trampoline.
instructions_length = RoundUpToInstrBoundary(kBranchLength, old_func);
if (!instructions_length)
return false;
// Put the needed instructions into the trampoline bytes.
uptr trampoline_length = instructions_length + kDirectBranchLength;
uptr trampoline = AllocateMemoryForTrampoline(old_func, trampoline_length);
if (!trampoline)
return false;
if (!CopyInstructions(trampoline, old_func, instructions_length))
return false;
WriteDirectBranch(trampoline + instructions_length,
old_func + instructions_length);
*orig_old_func = trampoline;
}
#if SANITIZER_WINDOWS64
// Check if the targeted address can be encoded in the function padding.
// Otherwise, allocate it in the trampoline region.
if (IsMemoryPadding(old_func - kAddressLength, kAddressLength)) {
indirect_address = old_func - kAddressLength;
padding_length = kAddressLength;
} else {
indirect_address = AllocateMemoryForTrampoline(old_func, kAddressLength);
if (!indirect_address)
return false;
}
#endif
// Change memory protection to writable.
uptr patch_address = old_func - padding_length;
uptr patch_length = instructions_length + padding_length;
DWORD protection = 0;
if (!ChangeMemoryProtection(patch_address, patch_length, &protection))
return false;
// Patch the original function.
WriteBranch(old_func, indirect_address, new_func);
// Restore previous memory protection.
if (!RestoreMemoryProtection(patch_address, patch_length, protection))
return false;
return true;
}
bool OverrideFunction(
uptr old_func, uptr new_func, uptr *orig_old_func) {
#if !SANITIZER_WINDOWS64
if (OverrideFunctionWithDetour(old_func, new_func, orig_old_func))
return true;
#endif
if (OverrideFunctionWithRedirectJump(old_func, new_func, orig_old_func))
return true;
if (OverrideFunctionWithHotPatch(old_func, new_func, orig_old_func))
return true;
if (OverrideFunctionWithTrampoline(old_func, new_func, orig_old_func))
return true;
return false;
}
static void **InterestingDLLsAvailable() {
static const char *InterestingDLLs[] = {
"kernel32.dll",
"msvcr100d.dll", // VS2010
"msvcr110d.dll", // VS2012
"msvcr120d.dll", // VS2013
"vcruntime140d.dll", // VS2015
"ucrtbased.dll", // Universal CRT
"msvcr100.dll", // VS2010
"msvcr110.dll", // VS2012
"msvcr120.dll", // VS2013
"vcruntime140.dll", // VS2015
"ucrtbase.dll", // Universal CRT
# if (defined(__MINGW32__) && defined(__i386__))
"libc++.dll", // libc++
"libunwind.dll", // libunwind
# endif
// NTDLL must go last as it gets special treatment in OverrideFunction.
"ntdll.dll",
NULL
};
static void *result[ARRAY_SIZE(InterestingDLLs)] = { 0 };
if (!result[0]) {
for (size_t i = 0, j = 0; InterestingDLLs[i]; ++i) {
if (HMODULE h = GetModuleHandleA(InterestingDLLs[i]))
result[j++] = (void *)h;
}
}
return &result[0];
}
namespace {
// Utility for reading loaded PE images.
template <typename T> class RVAPtr {
public:
RVAPtr(void *module, uptr rva)
: ptr_(reinterpret_cast<T *>(reinterpret_cast<char *>(module) + rva)) {}
operator T *() { return ptr_; }
T *operator->() { return ptr_; }
T *operator++() { return ++ptr_; }
private:
T *ptr_;
};
} // namespace
// Internal implementation of GetProcAddress. At least since Windows 8,
// GetProcAddress appears to initialize DLLs before returning function pointers
// into them. This is problematic for the sanitizers, because they typically
// want to intercept malloc *before* MSVCRT initializes. Our internal
// implementation walks the export list manually without doing initialization.
uptr InternalGetProcAddress(void *module, const char *func_name) {
// Check that the module header is full and present.
RVAPtr<IMAGE_DOS_HEADER> dos_stub(module, 0);
RVAPtr<IMAGE_NT_HEADERS> headers(module, dos_stub->e_lfanew);
if (!module || dos_stub->e_magic != IMAGE_DOS_SIGNATURE || // "MZ"
headers->Signature != IMAGE_NT_SIGNATURE || // "PE\0\0"
headers->FileHeader.SizeOfOptionalHeader <
sizeof(IMAGE_OPTIONAL_HEADER)) {
return 0;
}
IMAGE_DATA_DIRECTORY *export_directory =
&headers->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT];
if (export_directory->Size == 0)
return 0;
RVAPtr<IMAGE_EXPORT_DIRECTORY> exports(module,
export_directory->VirtualAddress);
RVAPtr<DWORD> functions(module, exports->AddressOfFunctions);
RVAPtr<DWORD> names(module, exports->AddressOfNames);
RVAPtr<WORD> ordinals(module, exports->AddressOfNameOrdinals);
for (DWORD i = 0; i < exports->NumberOfNames; i++) {
RVAPtr<char> name(module, names[i]);
if (!_strcmp(func_name, name)) {
DWORD index = ordinals[i];
RVAPtr<char> func(module, functions[index]);
// Handle forwarded functions.
DWORD offset = functions[index];
if (offset >= export_directory->VirtualAddress &&
offset < export_directory->VirtualAddress + export_directory->Size) {
// An entry for a forwarded function is a string with the following
// format: "<module> . <function_name>" that is stored into the
// exported directory.
char function_name[256];
size_t funtion_name_length = _strlen(func);
if (funtion_name_length >= sizeof(function_name) - 1) {
ReportError("interception_win: func too long: '%s'\n", (char *)func);
InterceptionFailed();
}
_memcpy(function_name, func, funtion_name_length);
function_name[funtion_name_length] = '\0';
char* separator = _strchr(function_name, '.');
if (!separator) {
ReportError("interception_win: no separator in '%s'\n",
function_name);
InterceptionFailed();
}
*separator = '\0';
void* redirected_module = GetModuleHandleA(function_name);
if (!redirected_module) {
ReportError("interception_win: GetModuleHandleA failed for '%s'\n",
function_name);
InterceptionFailed();
}
return InternalGetProcAddress(redirected_module, separator + 1);
}
return (uptr)(char *)func;
}
}
return 0;
}
bool OverrideFunction(
const char *func_name, uptr new_func, uptr *orig_old_func) {
static const char *kNtDllIgnore[] = {
"memcmp", "memcpy", "memmove", "memset"
};
bool hooked = false;
void **DLLs = InterestingDLLsAvailable();
for (size_t i = 0; DLLs[i]; ++i) {
if (DLLs[i + 1] == nullptr) {
// This is the last DLL, i.e. NTDLL. It exports some functions that
// we only want to override in the CRT.
for (const char *ignored : kNtDllIgnore) {
if (_strcmp(func_name, ignored) == 0)
return hooked;
}
}
uptr func_addr = InternalGetProcAddress(DLLs[i], func_name);
if (func_addr &&
OverrideFunction(func_addr, new_func, orig_old_func)) {
hooked = true;
}
}
return hooked;
}
bool OverrideImportedFunction(const char *module_to_patch,
const char *imported_module,
const char *function_name, uptr new_function,
uptr *orig_old_func) {
HMODULE module = GetModuleHandleA(module_to_patch);
if (!module)
return false;
// Check that the module header is full and present.
RVAPtr<IMAGE_DOS_HEADER> dos_stub(module, 0);
RVAPtr<IMAGE_NT_HEADERS> headers(module, dos_stub->e_lfanew);
if (!module || dos_stub->e_magic != IMAGE_DOS_SIGNATURE || // "MZ"
headers->Signature != IMAGE_NT_SIGNATURE || // "PE\0\0"
headers->FileHeader.SizeOfOptionalHeader <
sizeof(IMAGE_OPTIONAL_HEADER)) {
return false;
}
IMAGE_DATA_DIRECTORY *import_directory =
&headers->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT];
// Iterate the list of imported DLLs. FirstThunk will be null for the last
// entry.
RVAPtr<IMAGE_IMPORT_DESCRIPTOR> imports(module,
import_directory->VirtualAddress);
for (; imports->FirstThunk != 0; ++imports) {
RVAPtr<const char> modname(module, imports->Name);
if (_stricmp(&*modname, imported_module) == 0)
break;
}
if (imports->FirstThunk == 0)
return false;
// We have two parallel arrays: the import address table (IAT) and the table
// of names. They start out containing the same data, but the loader rewrites
// the IAT to hold imported addresses and leaves the name table in
// OriginalFirstThunk alone.
RVAPtr<IMAGE_THUNK_DATA> name_table(module, imports->OriginalFirstThunk);
RVAPtr<IMAGE_THUNK_DATA> iat(module, imports->FirstThunk);
for (; name_table->u1.Ordinal != 0; ++name_table, ++iat) {
if (!IMAGE_SNAP_BY_ORDINAL(name_table->u1.Ordinal)) {
RVAPtr<IMAGE_IMPORT_BY_NAME> import_by_name(
module, name_table->u1.ForwarderString);
const char *funcname = &import_by_name->Name[0];
if (_strcmp(funcname, function_name) == 0)
break;
}
}
if (name_table->u1.Ordinal == 0)
return false;
// Now we have the correct IAT entry. Do the swap. We have to make the page
// read/write first.
if (orig_old_func)
*orig_old_func = iat->u1.AddressOfData;
DWORD old_prot, unused_prot;
if (!VirtualProtect(&iat->u1.AddressOfData, 4, PAGE_EXECUTE_READWRITE,
&old_prot))
return false;
iat->u1.AddressOfData = new_function;
if (!VirtualProtect(&iat->u1.AddressOfData, 4, old_prot, &unused_prot))
return false; // Not clear if this failure bothers us.
return true;
}
} // namespace __interception
#endif // SANITIZER_WINDOWS
|
