| //===-- 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 |
