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Diffstat (limited to 'lib/interception/interception_win.cpp')
| -rw-r--r-- | lib/interception/interception_win.cpp | 1022 |
1 files changed, 1022 insertions, 0 deletions
diff --git a/lib/interception/interception_win.cpp b/lib/interception/interception_win.cpp new file mode 100644 index 0000000000000..1a1c327e61240 --- /dev/null +++ b/lib/interception/interception_win.cpp @@ -0,0 +1,1022 @@ +//===-- 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 |