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diff --git a/lib/interception/interception_win.cpp b/lib/interception/interception_win.cpp
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+//===-- interception_linux.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 an 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 an 64-bit architecture, a trampoline is inserted.
+//
+// func: jmp <label> --> func: jmp <tramp>
+// [...]
+//
+// [trampoline]
+// tramp: jmp QWORD [addr]
+// addr: .bytes <hook>
+//
+// Note: <real> is equilavent to <label>.
+//
+// 3) HotPatch
+//
+// The HotPatch hooking is assuming the presence of an 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 an 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 an 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>
+
+namespace __interception {
+
+static const int kAddressLength = FIRST_32_SECOND_64(4, 8);
+static const int kJumpInstructionLength = 5;
+static const int kShortJumpInstructionLength = 2;
+static const int kIndirectJumpInstructionLength = 6;
+static const int kBranchLength =
+ FIRST_32_SECOND_64(kJumpInstructionLength, kIndirectJumpInstructionLength);
+static const int kDirectBranchLength = kBranchLength + kAddressLength;
+
+static void InterceptionFailed() {
+ // Do we have a good way to abort with an error message here?
+ __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;
+}
+
+static uptr RoundUpTo(uptr size, uptr boundary) {
+ return (size + boundary - 1) & ~(boundary - 1);
+}
+
+// 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 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))
+ 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)
+ 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)) {
+ 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;
+};
+
+static const uptr kTrampolineScanLimitRange = 1 << 31; // 2 gig
+static const int kMaxTrampolineRegion = 1024;
+static TrampolineMemoryRegion TrampolineRegions[kMaxTrampolineRegion];
+
+static void *AllocateTrampolineRegion(uptr image_address, size_t granularity) {
+#if SANITIZER_WINDOWS64
+ uptr address = image_address;
+ uptr scanned = 0;
+ while (scanned < kTrampolineScanLimitRange) {
+ MEMORY_BASIC_INFORMATION info;
+ if (!::VirtualQuery((void*)address, &info, sizeof(info)))
+ return nullptr;
+
+ // Check whether a region can be allocated at |address|.
+ if (info.State == MEM_FREE && info.RegionSize >= granularity) {
+ void *page = ::VirtualAlloc((void*)RoundUpTo(address, granularity),
+ granularity,
+ MEM_RESERVE | MEM_COMMIT,
+ PAGE_EXECUTE_READWRITE);
+ return page;
+ }
+
+ // Move to the next region.
+ address = (uptr)info.BaseAddress + info.RegionSize;
+ scanned += info.RegionSize;
+ }
+ 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 image_address, size_t size) {
+ // Find a region within 2G 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(image_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) {
+#if SANITIZER_WINDOWS64
+ // In 64-bits, the memory space must be allocated within 2G boundary.
+ uptr next_address = current->content + current->allocated_size;
+ if (next_address < image_address ||
+ next_address - image_address >= 0x7FFF0000)
+ continue;
+#endif
+ // 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;
+}
+
+// Returns 0 on error.
+static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
+ switch (*(u64*)address) {
+ case 0x90909090909006EB: // stub: jmp over 6 x nop.
+ return 8;
+ }
+
+ switch (*(u8*)address) {
+ case 0x90: // 90 : nop
+ 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;
+
+ 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
+ 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 0xC3: // C3 : ret
+ 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 0xC18B: // 8B C1 : mov eax, ecx
+ case 0xC033: // 33 C0 : xor eax, eax
+ case 0xC933: // 33 C9 : xor ecx, ecx
+ case 0xD233: // 33 D2 : xor edx, edx
+ return 2;
+
+ // Cannot overwrite control-instruction. Return 0 to indicate failure.
+ case 0x25FF: // FF 25 XX XX XX XX : jmp [XXXXXXXX]
+ return 0;
+ }
+
+ switch (0x00FFFFFF & *(u32*)address) {
+ case 0x24A48D: // 8D A4 24 XX XX XX XX : lea esp, [esp + XX XX XX XX]
+ return 7;
+ }
+
+#if SANITIZER_WINDOWS64
+ switch (*(u8*)address) {
+ case 0xA1: // A1 XX XX XX XX XX XX XX XX :
+ // movabs eax, dword ptr ds:[XXXXXXXX]
+ return 9;
+ }
+
+ 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 0x9066: // Two-byte NOP
+ return 2;
+
+ case 0x058B: // 8B 05 XX XX XX XX : mov eax, dword ptr [XX XX XX XX]
+ if (rel_offset)
+ *rel_offset = 2;
+ return 6;
+ }
+
+ switch (0x00FFFFFF & *(u32*)address) {
+ case 0xe58948: // 48 8b c4 : mov rbp, rsp
+ case 0xc18b48: // 48 8b c1 : mov rax, rcx
+ case 0xc48b48: // 48 8b c4 : mov rax, rsp
+ case 0xd9f748: // 48 f7 d9 : neg rcx
+ case 0xd12b48: // 48 2b d1 : sub rdx, rcx
+ case 0x07c1f6: // f6 c1 07 : test cl, 0x7
+ case 0xc98548: // 48 85 C9 : test rcx, rcx
+ case 0xc0854d: // 4d 85 c0 : test r8, r8
+ case 0xc2b60f: // 0f b6 c2 : movzx eax, dl
+ case 0xc03345: // 45 33 c0 : xor r8d, r8d
+ case 0xc93345: // 45 33 c9 : xor r9d, r9d
+ case 0xdb3345: // 45 33 DB : xor r11d, r11d
+ case 0xd98b4c: // 4c 8b d9 : mov r11, rcx
+ case 0xd28b4c: // 4c 8b d2 : mov r10, rdx
+ case 0xc98b4c: // 4C 8B C9 : mov r9, rcx
+ case 0xc18b4c: // 4C 8B C1 : mov r8, rcx
+ case 0xd2b60f: // 0f b6 d2 : movzx edx, dl
+ case 0xca2b48: // 48 2b ca : sub rcx, rdx
+ case 0x10b70f: // 0f b7 10 : movzx edx, WORD PTR [rax]
+ case 0xc00b4d: // 3d 0b c0 : or r8, r8
+ case 0xd18b48: // 48 8b d1 : mov rdx, rcx
+ case 0xdc8b4c: // 4c 8b dc : mov r11, rsp
+ case 0xd18b4c: // 4c 8b d1 : mov r10, rcx
+ case 0xE0E483: // 83 E4 E0 : and esp, 0xFFFFFFE0
+ return 3;
+
+ case 0xec8348: // 48 83 ec XX : sub rsp, XX
+ case 0xf88349: // 49 83 f8 XX : cmp r8, XX
+ case 0x588948: // 48 89 58 XX : mov QWORD PTR[rax + XX], rbx
+ return 4;
+
+ case 0xec8148: // 48 81 EC XX XX XX XX : sub rsp, XXXXXXXX
+ return 7;
+
+ case 0x058b48: // 48 8b 05 XX XX XX XX :
+ // mov rax, QWORD PTR [rip + XXXXXXXX]
+ case 0x25ff48: // 48 ff 25 XX XX XX XX :
+ // rex.W jmp QWORD PTR [rip + XXXXXXXX]
+
+ // 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;
+ }
+
+ switch (*(u32*)(address)) {
+ 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 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
+ return 5;
+ case 0x24648348: // 48 83 64 24 XX : and QWORD PTR [rsp + XX], YY
+ return 6;
+ }
+
+#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 0xEC83: // 83 EC XX : sub esp, XX
+ case 0x75FF: // FF 75 XX : push dword ptr [ebp + XX]
+ return 3;
+ case 0xC1F7: // F7 C1 XX YY ZZ WW : test ecx, WWZZYYXX
+ case 0x25FF: // FF 25 XX YY ZZ WW : jmp dword ptr ds:[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 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!
+ // FIXME: Unknown instruction failures might happen when we add a new
+ // interceptor or a new compiler version. In either case, they should result
+ // in visible and readable error messages. However, merely calling abort()
+ // leads to an infinite recursion in CheckFailed.
+ InterceptionFailed();
+ return 0;
+}
+
+// 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);
+ _memcpy((void*)(to + cursor), (void*)(from + cursor),
+ (size_t)instruction_size);
+ if (rel_offset) {
+ uptr delta = to - from;
+ uptr relocated_offset = *(u32*)(to + cursor + rel_offset) - delta;
+#if SANITIZER_WINDOWS64
+ if (relocated_offset + 0x80000000U >= 0xFFFFFFFFU)
+ return false;
+#endif
+ *(u32*)(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) {
+ uptr relative_offset = *(u32*)(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",
+ "msvcr100.dll", // VS2010
+ "msvcr110.dll", // VS2012
+ "msvcr120.dll", // VS2013
+ "vcruntime140.dll", // VS2015
+ "ucrtbase.dll", // Universal CRT
+ // NTDLL should go last as it exports some functions that we should
+ // override in the CRT [presumably only used internally].
+ "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)
+ InterceptionFailed();
+
+ _memcpy(function_name, func, funtion_name_length);
+ function_name[funtion_name_length] = '\0';
+ char* separator = _strchr(function_name, '.');
+ if (!separator)
+ InterceptionFailed();
+ *separator = '\0';
+
+ void* redirected_module = GetModuleHandleA(function_name);
+ if (!redirected_module)
+ 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) {
+ bool hooked = false;
+ void **DLLs = InterestingDLLsAvailable();
+ for (size_t i = 0; DLLs[i]; ++i) {
+ 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_MAC