CoCalc -- interception

GitHub Repository: freebsd/freebsd-src
Path: blob/main/contrib/llvm-project/compiler-rt/lib/interception/interception_win.cpp
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//===-- interception_win.cpp ------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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//
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// Windows-specific interception methods.
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//
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// This file is implementing several hooking techniques to intercept calls
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// to functions. The hooks are dynamically installed by modifying the assembly
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// code.
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//
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// The hooking techniques are making assumptions on the way the code is
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// generated and are safe under these assumptions.
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//
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// On 64-bit architecture, there is no direct 64-bit jump instruction. To allow
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// arbitrary branching on the whole memory space, the notion of trampoline
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// region is used. A trampoline region is a memory space withing 2G boundary
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// where it is safe to add custom assembly code to build 64-bit jumps.
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//
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// Hooking techniques
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// ==================
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//
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// 1) Detour
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//
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//    The Detour hooking technique is assuming the presence of an header with
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//    padding and an overridable 2-bytes nop instruction (mov edi, edi). The
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//    nop instruction can safely be replaced by a 2-bytes jump without any need
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//    to save the instruction. A jump to the target is encoded in the function
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//    header and the nop instruction is replaced by a short jump to the header.
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//
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//        head:  5 x nop                 head:  jmp <hook>
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//        func:  mov edi, edi    -->     func:  jmp short <head>
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//               [...]                   real:  [...]
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//
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//    This technique is only implemented on 32-bit architecture.
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//    Most of the time, Windows API are hookable with the detour technique.
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//
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// 2) Redirect Jump
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//
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//    The redirect jump is applicable when the first instruction is a direct
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//    jump. The instruction is replaced by jump to the hook.
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//
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//        func:  jmp <label>     -->     func:  jmp <hook>
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//
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//    On an 64-bit architecture, a trampoline is inserted.
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//
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//        func:  jmp <label>     -->     func:  jmp <tramp>
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//                                              [...]
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//
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//                                   [trampoline]
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//                                      tramp:  jmp QWORD [addr]
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//                                       addr:  .bytes <hook>
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//
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//    Note: <real> is equivalent to <label>.
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//
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// 3) HotPatch
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//
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//    The HotPatch hooking is assuming the presence of an header with padding
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//    and a first instruction with at least 2-bytes.
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//
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//    The reason to enforce the 2-bytes limitation is to provide the minimal
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//    space to encode a short jump. HotPatch technique is only rewriting one
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//    instruction to avoid breaking a sequence of instructions containing a
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//    branching target.
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//
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//    Assumptions are enforced by MSVC compiler by using the /HOTPATCH flag.
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//      see: https://msdn.microsoft.com/en-us/library/ms173507.aspx
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//    Default padding length is 5 bytes in 32-bits and 6 bytes in 64-bits.
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//
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//        head:   5 x nop                head:  jmp <hook>
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//        func:   <instr>        -->     func:  jmp short <head>
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//                [...]                  body:  [...]
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//
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//                                   [trampoline]
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//                                       real:  <instr>
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//                                              jmp <body>
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//
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//    On an 64-bit architecture:
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//
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//        head:   6 x nop                head:  jmp QWORD [addr1]
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//        func:   <instr>        -->     func:  jmp short <head>
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//                [...]                  body:  [...]
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//
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//                                   [trampoline]
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//                                      addr1:  .bytes <hook>
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//                                       real:  <instr>
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//                                              jmp QWORD [addr2]
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//                                      addr2:  .bytes <body>
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//
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// 4) Trampoline
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//
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//    The Trampoline hooking technique is the most aggressive one. It is
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//    assuming that there is a sequence of instructions that can be safely
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//    replaced by a jump (enough room and no incoming branches).
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//
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//    Unfortunately, these assumptions can't be safely presumed and code may
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//    be broken after hooking.
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//
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//        func:   <instr>        -->     func:  jmp <hook>
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//                <instr>
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//                [...]                  body:  [...]
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//
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//                                   [trampoline]
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//                                       real:  <instr>
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//                                              <instr>
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//                                              jmp <body>
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//
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//    On an 64-bit architecture:
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//
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//        func:   <instr>        -->     func:  jmp QWORD [addr1]
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//                <instr>
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//                [...]                  body:  [...]
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//
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//                                   [trampoline]
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//                                      addr1:  .bytes <hook>
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//                                       real:  <instr>
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//                                              <instr>
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//                                              jmp QWORD [addr2]
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//                                      addr2:  .bytes <body>
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//===----------------------------------------------------------------------===//
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#include "interception.h"
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#if SANITIZER_WINDOWS
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#include "sanitizer_common/sanitizer_platform.h"
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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namespace __interception {
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static const int kAddressLength = FIRST_32_SECOND_64(4, 8);
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static const int kJumpInstructionLength = 5;
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static const int kShortJumpInstructionLength = 2;
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UNUSED static const int kIndirectJumpInstructionLength = 6;
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static const int kBranchLength =
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    FIRST_32_SECOND_64(kJumpInstructionLength, kIndirectJumpInstructionLength);
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static const int kDirectBranchLength = kBranchLength + kAddressLength;
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#  if defined(_MSC_VER)
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#    define INTERCEPTION_FORMAT(f, a)
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#  else
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#    define INTERCEPTION_FORMAT(f, a) __attribute__((format(printf, f, a)))
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#  endif
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static void (*ErrorReportCallback)(const char *format, ...)
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    INTERCEPTION_FORMAT(1, 2);
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153
void SetErrorReportCallback(void (*callback)(const char *format, ...)) {
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  ErrorReportCallback = callback;
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}
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#  define ReportError(...)                \
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    do {                                  \
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      if (ErrorReportCallback)            \
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        ErrorReportCallback(__VA_ARGS__); \
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    } while (0)
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static void InterceptionFailed() {
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  ReportError("interception_win: failed due to an unrecoverable error.\n");
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  // This acts like an abort when no debugger is attached. According to an old
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  // comment, calling abort() leads to an infinite recursion in CheckFailed.
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  __debugbreak();
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}
169

170
static bool DistanceIsWithin2Gig(uptr from, uptr target) {
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#if SANITIZER_WINDOWS64
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  if (from < target)
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    return target - from <= (uptr)0x7FFFFFFFU;
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  else
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    return from - target <= (uptr)0x80000000U;
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#else
177
  // In a 32-bit address space, the address calculation will wrap, so this check
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  // is unnecessary.
179
  return true;
180
#endif
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}
182

183
static uptr GetMmapGranularity() {
184
  SYSTEM_INFO si;
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  GetSystemInfo(&si);
186
  return si.dwAllocationGranularity;
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}
188

189
UNUSED static uptr RoundUpTo(uptr size, uptr boundary) {
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  return (size + boundary - 1) & ~(boundary - 1);
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}
192

193
// FIXME: internal_str* and internal_mem* functions should be moved from the
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// ASan sources into interception/.
195

196
static size_t _strlen(const char *str) {
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  const char* p = str;
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  while (*p != '\0') ++p;
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  return p - str;
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}
201

202
static char* _strchr(char* str, char c) {
203
  while (*str) {
204
    if (*str == c)
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      return str;
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    ++str;
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  }
208
  return nullptr;
209
}
210

211
static void _memset(void *p, int value, size_t sz) {
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  for (size_t i = 0; i < sz; ++i)
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    ((char*)p)[i] = (char)value;
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}
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static void _memcpy(void *dst, void *src, size_t sz) {
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  char *dst_c = (char*)dst,
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       *src_c = (char*)src;
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  for (size_t i = 0; i < sz; ++i)
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    dst_c[i] = src_c[i];
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}
222

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static bool ChangeMemoryProtection(
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    uptr address, uptr size, DWORD *old_protection) {
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  return ::VirtualProtect((void*)address, size,
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                          PAGE_EXECUTE_READWRITE,
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                          old_protection) != FALSE;
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}
229

230
static bool RestoreMemoryProtection(
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    uptr address, uptr size, DWORD old_protection) {
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  DWORD unused;
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  return ::VirtualProtect((void*)address, size,
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                          old_protection,
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                          &unused) != FALSE;
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}
237

238
static bool IsMemoryPadding(uptr address, uptr size) {
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  u8* function = (u8*)address;
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  for (size_t i = 0; i < size; ++i)
241
    if (function[i] != 0x90 && function[i] != 0xCC)
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      return false;
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  return true;
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}
245

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static const u8 kHintNop8Bytes[] = {
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  0x0F, 0x1F, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00
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};
249

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template<class T>
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static bool FunctionHasPrefix(uptr address, const T &pattern) {
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  u8* function = (u8*)address - sizeof(pattern);
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  for (size_t i = 0; i < sizeof(pattern); ++i)
254
    if (function[i] != pattern[i])
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      return false;
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  return true;
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}
258

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static bool FunctionHasPadding(uptr address, uptr size) {
260
  if (IsMemoryPadding(address - size, size))
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    return true;
262
  if (size <= sizeof(kHintNop8Bytes) &&
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      FunctionHasPrefix(address, kHintNop8Bytes))
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    return true;
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  return false;
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}
267

268
static void WritePadding(uptr from, uptr size) {
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  _memset((void*)from, 0xCC, (size_t)size);
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}
271

272
static void WriteJumpInstruction(uptr from, uptr target) {
273
  if (!DistanceIsWithin2Gig(from + kJumpInstructionLength, target)) {
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    ReportError(
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        "interception_win: cannot write jmp further than 2GB away, from %p to "
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        "%p.\n",
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        (void *)from, (void *)target);
278
    InterceptionFailed();
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  }
280
  ptrdiff_t offset = target - from - kJumpInstructionLength;
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  *(u8*)from = 0xE9;
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  *(u32*)(from + 1) = offset;
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}
284

285
static void WriteShortJumpInstruction(uptr from, uptr target) {
286
  sptr offset = target - from - kShortJumpInstructionLength;
287
  if (offset < -128 || offset > 127)
288
    InterceptionFailed();
289
  *(u8*)from = 0xEB;
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  *(u8*)(from + 1) = (u8)offset;
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}
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293
#if SANITIZER_WINDOWS64
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static void WriteIndirectJumpInstruction(uptr from, uptr indirect_target) {
295
  // jmp [rip + <offset>] = FF 25 <offset> where <offset> is a relative
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  // offset.
297
  // The offset is the distance from then end of the jump instruction to the
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  // memory location containing the targeted address. The displacement is still
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  // 32-bit in x64, so indirect_target must be located within +/- 2GB range.
300
  int offset = indirect_target - from - kIndirectJumpInstructionLength;
301
  if (!DistanceIsWithin2Gig(from + kIndirectJumpInstructionLength,
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                            indirect_target)) {
303
    ReportError(
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        "interception_win: cannot write indirect jmp with target further than "
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        "2GB away, from %p to %p.\n",
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        (void *)from, (void *)indirect_target);
307
    InterceptionFailed();
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  }
309
  *(u16*)from = 0x25FF;
310
  *(u32*)(from + 2) = offset;
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}
312
#endif
313

314
static void WriteBranch(
315
    uptr from, uptr indirect_target, uptr target) {
316
#if SANITIZER_WINDOWS64
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  WriteIndirectJumpInstruction(from, indirect_target);
318
  *(u64*)indirect_target = target;
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#else
320
  (void)indirect_target;
321
  WriteJumpInstruction(from, target);
322
#endif
323
}
324

325
static void WriteDirectBranch(uptr from, uptr target) {
326
#if SANITIZER_WINDOWS64
327
  // Emit an indirect jump through immediately following bytes:
328
  //   jmp [rip + kBranchLength]
329
  //   .quad <target>
330
  WriteBranch(from, from + kBranchLength, target);
331
#else
332
  WriteJumpInstruction(from, target);
333
#endif
334
}
335

336
struct TrampolineMemoryRegion {
337
  uptr content;
338
  uptr allocated_size;
339
  uptr max_size;
340
};
341

342
UNUSED static const uptr kTrampolineScanLimitRange = 1ull << 31;  // 2 gig
343
static const int kMaxTrampolineRegion = 1024;
344
static TrampolineMemoryRegion TrampolineRegions[kMaxTrampolineRegion];
345

346
static void *AllocateTrampolineRegion(uptr image_address, size_t granularity) {
347
#if SANITIZER_WINDOWS64
348
  uptr address = image_address;
349
  uptr scanned = 0;
350
  while (scanned < kTrampolineScanLimitRange) {
351
    MEMORY_BASIC_INFORMATION info;
352
    if (!::VirtualQuery((void*)address, &info, sizeof(info)))
353
      return nullptr;
354

355
    // Check whether a region can be allocated at |address|.
356
    if (info.State == MEM_FREE && info.RegionSize >= granularity) {
357
      void *page = ::VirtualAlloc((void*)RoundUpTo(address, granularity),
358
                                  granularity,
359
                                  MEM_RESERVE | MEM_COMMIT,
360
                                  PAGE_EXECUTE_READWRITE);
361
      return page;
362
    }
363

364
    // Move to the next region.
365
    address = (uptr)info.BaseAddress + info.RegionSize;
366
    scanned += info.RegionSize;
367
  }
368
  return nullptr;
369
#else
370
  return ::VirtualAlloc(nullptr,
371
                        granularity,
372
                        MEM_RESERVE | MEM_COMMIT,
373
                        PAGE_EXECUTE_READWRITE);
374
#endif
375
}
376

377
// Used by unittests to release mapped memory space.
378
void TestOnlyReleaseTrampolineRegions() {
379
  for (size_t bucket = 0; bucket < kMaxTrampolineRegion; ++bucket) {
380
    TrampolineMemoryRegion *current = &TrampolineRegions[bucket];
381
    if (current->content == 0)
382
      return;
383
    ::VirtualFree((void*)current->content, 0, MEM_RELEASE);
384
    current->content = 0;
385
  }
386
}
387

388
static uptr AllocateMemoryForTrampoline(uptr image_address, size_t size) {
389
  // Find a region within 2G with enough space to allocate |size| bytes.
390
  TrampolineMemoryRegion *region = nullptr;
391
  for (size_t bucket = 0; bucket < kMaxTrampolineRegion; ++bucket) {
392
    TrampolineMemoryRegion* current = &TrampolineRegions[bucket];
393
    if (current->content == 0) {
394
      // No valid region found, allocate a new region.
395
      size_t bucket_size = GetMmapGranularity();
396
      void *content = AllocateTrampolineRegion(image_address, bucket_size);
397
      if (content == nullptr)
398
        return 0U;
399

400
      current->content = (uptr)content;
401
      current->allocated_size = 0;
402
      current->max_size = bucket_size;
403
      region = current;
404
      break;
405
    } else if (current->max_size - current->allocated_size > size) {
406
#if SANITIZER_WINDOWS64
407
        // In 64-bits, the memory space must be allocated within 2G boundary.
408
        uptr next_address = current->content + current->allocated_size;
409
        if (next_address < image_address ||
410
            next_address - image_address >= 0x7FFF0000)
411
          continue;
412
#endif
413
      // The space can be allocated in the current region.
414
      region = current;
415
      break;
416
    }
417
  }
418

419
  // Failed to find a region.
420
  if (region == nullptr)
421
    return 0U;
422

423
  // Allocate the space in the current region.
424
  uptr allocated_space = region->content + region->allocated_size;
425
  region->allocated_size += size;
426
  WritePadding(allocated_space, size);
427

428
  return allocated_space;
429
}
430

431
// The following prologues cannot be patched because of the short jump
432
// jumping to the patching region.
433

434
// Short jump patterns  below are only for x86_64.
435
#  if SANITIZER_WINDOWS_x64
436
// ntdll!wcslen in Win11
437
//   488bc1          mov     rax,rcx
438
//   0fb710          movzx   edx,word ptr [rax]
439
//   4883c002        add     rax,2
440
//   6685d2          test    dx,dx
441
//   75f4            jne     -12
442
static const u8 kPrologueWithShortJump1[] = {
443
    0x48, 0x8b, 0xc1, 0x0f, 0xb7, 0x10, 0x48, 0x83,
444
    0xc0, 0x02, 0x66, 0x85, 0xd2, 0x75, 0xf4,
445
};
446

447
// ntdll!strrchr in Win11
448
//   4c8bc1          mov     r8,rcx
449
//   8a01            mov     al,byte ptr [rcx]
450
//   48ffc1          inc     rcx
451
//   84c0            test    al,al
452
//   75f7            jne     -9
453
static const u8 kPrologueWithShortJump2[] = {
454
    0x4c, 0x8b, 0xc1, 0x8a, 0x01, 0x48, 0xff, 0xc1,
455
    0x84, 0xc0, 0x75, 0xf7,
456
};
457
#endif
458

459
// Returns 0 on error.
460
static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
461
#if SANITIZER_ARM64
462
  // An ARM64 instruction is 4 bytes long.
463
  return 4;
464
#endif
465

466
#  if SANITIZER_WINDOWS_x64
467
  if (memcmp((u8*)address, kPrologueWithShortJump1,
468
             sizeof(kPrologueWithShortJump1)) == 0 ||
469
      memcmp((u8*)address, kPrologueWithShortJump2,
470
             sizeof(kPrologueWithShortJump2)) == 0) {
471
    return 0;
472
  }
473
#endif
474

475
  switch (*(u64*)address) {
476
    case 0x90909090909006EB:  // stub: jmp over 6 x nop.
477
      return 8;
478
  }
479

480
  switch (*(u8*)address) {
481
    case 0x90:  // 90 : nop
482
    case 0xC3:  // C3 : ret   (for small/empty function interception
483
    case 0xCC:  // CC : int 3  i.e. registering weak functions)
484
      return 1;
485

486
    case 0x50:  // push eax / rax
487
    case 0x51:  // push ecx / rcx
488
    case 0x52:  // push edx / rdx
489
    case 0x53:  // push ebx / rbx
490
    case 0x54:  // push esp / rsp
491
    case 0x55:  // push ebp / rbp
492
    case 0x56:  // push esi / rsi
493
    case 0x57:  // push edi / rdi
494
    case 0x5D:  // pop ebp / rbp
495
      return 1;
496

497
    case 0x6A:  // 6A XX = push XX
498
      return 2;
499

500
    case 0xb8:  // b8 XX XX XX XX : mov eax, XX XX XX XX
501
    case 0xB9:  // b9 XX XX XX XX : mov ecx, XX XX XX XX
502
      return 5;
503

504
    // Cannot overwrite control-instruction. Return 0 to indicate failure.
505
    case 0xE9:  // E9 XX XX XX XX : jmp <label>
506
    case 0xE8:  // E8 XX XX XX XX : call <func>
507
    case 0xEB:  // EB XX : jmp XX (short jump)
508
    case 0x70:  // 7Y YY : jy XX (short conditional jump)
509
    case 0x71:
510
    case 0x72:
511
    case 0x73:
512
    case 0x74:
513
    case 0x75:
514
    case 0x76:
515
    case 0x77:
516
    case 0x78:
517
    case 0x79:
518
    case 0x7A:
519
    case 0x7B:
520
    case 0x7C:
521
    case 0x7D:
522
    case 0x7E:
523
    case 0x7F:
524
      return 0;
525
  }
526

527
  switch (*(u16*)(address)) {
528
    case 0x018A:  // 8A 01 : mov al, byte ptr [ecx]
529
    case 0xFF8B:  // 8B FF : mov edi, edi
530
    case 0xEC8B:  // 8B EC : mov ebp, esp
531
    case 0xc889:  // 89 C8 : mov eax, ecx
532
    case 0xE589:  // 89 E5 : mov ebp, esp
533
    case 0xC18B:  // 8B C1 : mov eax, ecx
534
    case 0xC033:  // 33 C0 : xor eax, eax
535
    case 0xC933:  // 33 C9 : xor ecx, ecx
536
    case 0xD233:  // 33 D2 : xor edx, edx
537
      return 2;
538

539
    // Cannot overwrite control-instruction. Return 0 to indicate failure.
540
    case 0x25FF:  // FF 25 XX XX XX XX : jmp [XXXXXXXX]
541
      return 0;
542
  }
543

544
  switch (0x00FFFFFF & *(u32*)address) {
545
    case 0x24A48D:  // 8D A4 24 XX XX XX XX : lea esp, [esp + XX XX XX XX]
546
      return 7;
547
  }
548

549
  switch (0x000000FF & *(u32 *)address) {
550
    case 0xc2:  // C2 XX XX : ret XX (needed for registering weak functions)
551
      return 3;
552
  }
553

554
#  if SANITIZER_WINDOWS_x64
555
  switch (*(u8*)address) {
556
    case 0xA1:  // A1 XX XX XX XX XX XX XX XX :
557
                //   movabs eax, dword ptr ds:[XXXXXXXX]
558
      return 9;
559

560
    case 0x83:
561
      const u8 next_byte = *(u8*)(address + 1);
562
      const u8 mod = next_byte >> 6;
563
      const u8 rm = next_byte & 7;
564
      if (mod == 1 && rm == 4)
565
        return 5;  // 83 ModR/M SIB Disp8 Imm8
566
                   //   add|or|adc|sbb|and|sub|xor|cmp [r+disp8], imm8
567
  }
568

569
  switch (*(u16*)address) {
570
    case 0x5040:  // push rax
571
    case 0x5140:  // push rcx
572
    case 0x5240:  // push rdx
573
    case 0x5340:  // push rbx
574
    case 0x5440:  // push rsp
575
    case 0x5540:  // push rbp
576
    case 0x5640:  // push rsi
577
    case 0x5740:  // push rdi
578
    case 0x5441:  // push r12
579
    case 0x5541:  // push r13
580
    case 0x5641:  // push r14
581
    case 0x5741:  // push r15
582
    case 0x9066:  // Two-byte NOP
583
    case 0xc084:  // test al, al
584
    case 0x018a:  // mov al, byte ptr [rcx]
585
      return 2;
586

587
    case 0x058A:  // 8A 05 XX XX XX XX : mov al, byte ptr [XX XX XX XX]
588
    case 0x058B:  // 8B 05 XX XX XX XX : mov eax, dword ptr [XX XX XX XX]
589
      if (rel_offset)
590
        *rel_offset = 2;
591
      return 6;
592
  }
593

594
  switch (0x00FFFFFF & *(u32*)address) {
595
    case 0xe58948:    // 48 8b c4 : mov rbp, rsp
596
    case 0xc18b48:    // 48 8b c1 : mov rax, rcx
597
    case 0xc48b48:    // 48 8b c4 : mov rax, rsp
598
    case 0xd9f748:    // 48 f7 d9 : neg rcx
599
    case 0xd12b48:    // 48 2b d1 : sub rdx, rcx
600
    case 0x07c1f6:    // f6 c1 07 : test cl, 0x7
601
    case 0xc98548:    // 48 85 C9 : test rcx, rcx
602
    case 0xd28548:    // 48 85 d2 : test rdx, rdx
603
    case 0xc0854d:    // 4d 85 c0 : test r8, r8
604
    case 0xc2b60f:    // 0f b6 c2 : movzx eax, dl
605
    case 0xc03345:    // 45 33 c0 : xor r8d, r8d
606
    case 0xc93345:    // 45 33 c9 : xor r9d, r9d
607
    case 0xdb3345:    // 45 33 DB : xor r11d, r11d
608
    case 0xd98b4c:    // 4c 8b d9 : mov r11, rcx
609
    case 0xd28b4c:    // 4c 8b d2 : mov r10, rdx
610
    case 0xc98b4c:    // 4C 8B C9 : mov r9, rcx
611
    case 0xc18b4c:    // 4C 8B C1 : mov r8, rcx
612
    case 0xd2b60f:    // 0f b6 d2 : movzx edx, dl
613
    case 0xca2b48:    // 48 2b ca : sub rcx, rdx
614
    case 0xca3b48:    // 48 3b ca : cmp rcx, rdx
615
    case 0x10b70f:    // 0f b7 10 : movzx edx, WORD PTR [rax]
616
    case 0xc00b4d:    // 3d 0b c0 : or r8, r8
617
    case 0xc08b41:    // 41 8b c0 : mov eax, r8d
618
    case 0xd18b48:    // 48 8b d1 : mov rdx, rcx
619
    case 0xdc8b4c:    // 4c 8b dc : mov r11, rsp
620
    case 0xd18b4c:    // 4c 8b d1 : mov r10, rcx
621
    case 0xE0E483:    // 83 E4 E0 : and esp, 0xFFFFFFE0
622
      return 3;
623

624
    case 0xec8348:    // 48 83 ec XX : sub rsp, XX
625
    case 0xf88349:    // 49 83 f8 XX : cmp r8, XX
626
    case 0x588948:    // 48 89 58 XX : mov QWORD PTR[rax + XX], rbx
627
      return 4;
628

629
    case 0xec8148:    // 48 81 EC XX XX XX XX : sub rsp, XXXXXXXX
630
      return 7;
631

632
    case 0x058b48:    // 48 8b 05 XX XX XX XX :
633
                      //   mov rax, QWORD PTR [rip + XXXXXXXX]
634
    case 0x058d48:    // 48 8d 05 XX XX XX XX :
635
                      //   lea rax, QWORD PTR [rip + XXXXXXXX]
636
    case 0x25ff48:    // 48 ff 25 XX XX XX XX :
637
                      //   rex.W jmp QWORD PTR [rip + XXXXXXXX]
638
    case 0x158D4C:    // 4c 8d 15 XX XX XX XX : lea r10, [rip + XX]
639
      // Instructions having offset relative to 'rip' need offset adjustment.
640
      if (rel_offset)
641
        *rel_offset = 3;
642
      return 7;
643

644
    case 0x2444c7:    // C7 44 24 XX YY YY YY YY
645
                      //   mov dword ptr [rsp + XX], YYYYYYYY
646
      return 8;
647
  }
648

649
  switch (*(u32*)(address)) {
650
    case 0x24448b48:  // 48 8b 44 24 XX : mov rax, QWORD ptr [rsp + XX]
651
    case 0x246c8948:  // 48 89 6C 24 XX : mov QWORD ptr [rsp + XX], rbp
652
    case 0x245c8948:  // 48 89 5c 24 XX : mov QWORD PTR [rsp + XX], rbx
653
    case 0x24748948:  // 48 89 74 24 XX : mov QWORD PTR [rsp + XX], rsi
654
    case 0x247c8948:  // 48 89 7c 24 XX : mov QWORD PTR [rsp + XX], rdi
655
    case 0x244C8948:  // 48 89 4C 24 XX : mov QWORD PTR [rsp + XX], rcx
656
    case 0x24548948:  // 48 89 54 24 XX : mov QWORD PTR [rsp + XX], rdx
657
    case 0x244c894c:  // 4c 89 4c 24 XX : mov QWORD PTR [rsp + XX], r9
658
    case 0x2444894c:  // 4c 89 44 24 XX : mov QWORD PTR [rsp + XX], r8
659
      return 5;
660
    case 0x24648348:  // 48 83 64 24 XX : and QWORD PTR [rsp + XX], YY
661
      return 6;
662
  }
663

664
#else
665

666
  switch (*(u8*)address) {
667
    case 0xA1:  // A1 XX XX XX XX :  mov eax, dword ptr ds:[XXXXXXXX]
668
      return 5;
669
  }
670
  switch (*(u16*)address) {
671
    case 0x458B:  // 8B 45 XX : mov eax, dword ptr [ebp + XX]
672
    case 0x5D8B:  // 8B 5D XX : mov ebx, dword ptr [ebp + XX]
673
    case 0x7D8B:  // 8B 7D XX : mov edi, dword ptr [ebp + XX]
674
    case 0xEC83:  // 83 EC XX : sub esp, XX
675
    case 0x75FF:  // FF 75 XX : push dword ptr [ebp + XX]
676
      return 3;
677
    case 0xC1F7:  // F7 C1 XX YY ZZ WW : test ecx, WWZZYYXX
678
    case 0x25FF:  // FF 25 XX YY ZZ WW : jmp dword ptr ds:[WWZZYYXX]
679
      return 6;
680
    case 0x3D83:  // 83 3D XX YY ZZ WW TT : cmp TT, WWZZYYXX
681
      return 7;
682
    case 0x7D83:  // 83 7D XX YY : cmp dword ptr [ebp + XX], YY
683
      return 4;
684
  }
685

686
  switch (0x00FFFFFF & *(u32*)address) {
687
    case 0x24448A:  // 8A 44 24 XX : mov eal, dword ptr [esp + XX]
688
    case 0x24448B:  // 8B 44 24 XX : mov eax, dword ptr [esp + XX]
689
    case 0x244C8B:  // 8B 4C 24 XX : mov ecx, dword ptr [esp + XX]
690
    case 0x24548B:  // 8B 54 24 XX : mov edx, dword ptr [esp + XX]
691
    case 0x245C8B:  // 8B 5C 24 XX : mov ebx, dword ptr [esp + XX]
692
    case 0x246C8B:  // 8B 6C 24 XX : mov ebp, dword ptr [esp + XX]
693
    case 0x24748B:  // 8B 74 24 XX : mov esi, dword ptr [esp + XX]
694
    case 0x247C8B:  // 8B 7C 24 XX : mov edi, dword ptr [esp + XX]
695
      return 4;
696
  }
697

698
  switch (*(u32*)address) {
699
    case 0x2444B60F:  // 0F B6 44 24 XX : movzx eax, byte ptr [esp + XX]
700
      return 5;
701
  }
702
#endif
703

704
  // Unknown instruction! This might happen when we add a new interceptor, use
705
  // a new compiler version, or if Windows changed how some functions are
706
  // compiled. In either case, we print the address and 8 bytes of instructions
707
  // to notify the user about the error and to help identify the unknown
708
  // instruction. Don't treat this as a fatal error, though we can break the
709
  // debugger if one has been attached.
710
  u8 *bytes = (u8 *)address;
711
  ReportError(
712
      "interception_win: unhandled instruction at %p: %02x %02x %02x %02x %02x "
713
      "%02x %02x %02x\n",
714
      (void *)address, bytes[0], bytes[1], bytes[2], bytes[3], bytes[4],
715
      bytes[5], bytes[6], bytes[7]);
716
  if (::IsDebuggerPresent())
717
    __debugbreak();
718
  return 0;
719
}
720

721
// Returns 0 on error.
722
static size_t RoundUpToInstrBoundary(size_t size, uptr address) {
723
  size_t cursor = 0;
724
  while (cursor < size) {
725
    size_t instruction_size = GetInstructionSize(address + cursor);
726
    if (!instruction_size)
727
      return 0;
728
    cursor += instruction_size;
729
  }
730
  return cursor;
731
}
732

733
static bool CopyInstructions(uptr to, uptr from, size_t size) {
734
  size_t cursor = 0;
735
  while (cursor != size) {
736
    size_t rel_offset = 0;
737
    size_t instruction_size = GetInstructionSize(from + cursor, &rel_offset);
738
    if (!instruction_size)
739
      return false;
740
    _memcpy((void *)(to + cursor), (void *)(from + cursor),
741
            (size_t)instruction_size);
742
    if (rel_offset) {
743
#  if SANITIZER_WINDOWS64
744
      // we want to make sure that the new relative offset still fits in 32-bits
745
      // this will be untrue if relocated_offset \notin [-2**31, 2**31)
746
      s64 delta = to - from;
747
      s64 relocated_offset = *(s32 *)(to + cursor + rel_offset) - delta;
748
      if (-0x8000'0000ll > relocated_offset || relocated_offset > 0x7FFF'FFFFll)
749
        return false;
750
#  else
751
      // on 32-bit, the relative offset will always be correct
752
      s32 delta = to - from;
753
      s32 relocated_offset = *(s32 *)(to + cursor + rel_offset) - delta;
754
#  endif
755
      *(s32 *)(to + cursor + rel_offset) = relocated_offset;
756
    }
757
    cursor += instruction_size;
758
  }
759
  return true;
760
}
761

762

763
#if !SANITIZER_WINDOWS64
764
bool OverrideFunctionWithDetour(
765
    uptr old_func, uptr new_func, uptr *orig_old_func) {
766
  const int kDetourHeaderLen = 5;
767
  const u16 kDetourInstruction = 0xFF8B;
768

769
  uptr header = (uptr)old_func - kDetourHeaderLen;
770
  uptr patch_length = kDetourHeaderLen + kShortJumpInstructionLength;
771

772
  // Validate that the function is hookable.
773
  if (*(u16*)old_func != kDetourInstruction ||
774
      !IsMemoryPadding(header, kDetourHeaderLen))
775
    return false;
776

777
  // Change memory protection to writable.
778
  DWORD protection = 0;
779
  if (!ChangeMemoryProtection(header, patch_length, &protection))
780
    return false;
781

782
  // Write a relative jump to the redirected function.
783
  WriteJumpInstruction(header, new_func);
784

785
  // Write the short jump to the function prefix.
786
  WriteShortJumpInstruction(old_func, header);
787

788
  // Restore previous memory protection.
789
  if (!RestoreMemoryProtection(header, patch_length, protection))
790
    return false;
791

792
  if (orig_old_func)
793
    *orig_old_func = old_func + kShortJumpInstructionLength;
794

795
  return true;
796
}
797
#endif
798

799
bool OverrideFunctionWithRedirectJump(
800
    uptr old_func, uptr new_func, uptr *orig_old_func) {
801
  // Check whether the first instruction is a relative jump.
802
  if (*(u8*)old_func != 0xE9)
803
    return false;
804

805
  if (orig_old_func) {
806
    sptr relative_offset = *(s32 *)(old_func + 1);
807
    uptr absolute_target = old_func + relative_offset + kJumpInstructionLength;
808
    *orig_old_func = absolute_target;
809
  }
810

811
#if SANITIZER_WINDOWS64
812
  // If needed, get memory space for a trampoline jump.
813
  uptr trampoline = AllocateMemoryForTrampoline(old_func, kDirectBranchLength);
814
  if (!trampoline)
815
    return false;
816
  WriteDirectBranch(trampoline, new_func);
817
#endif
818

819
  // Change memory protection to writable.
820
  DWORD protection = 0;
821
  if (!ChangeMemoryProtection(old_func, kJumpInstructionLength, &protection))
822
    return false;
823

824
  // Write a relative jump to the redirected function.
825
  WriteJumpInstruction(old_func, FIRST_32_SECOND_64(new_func, trampoline));
826

827
  // Restore previous memory protection.
828
  if (!RestoreMemoryProtection(old_func, kJumpInstructionLength, protection))
829
    return false;
830

831
  return true;
832
}
833

834
bool OverrideFunctionWithHotPatch(
835
    uptr old_func, uptr new_func, uptr *orig_old_func) {
836
  const int kHotPatchHeaderLen = kBranchLength;
837

838
  uptr header = (uptr)old_func - kHotPatchHeaderLen;
839
  uptr patch_length = kHotPatchHeaderLen + kShortJumpInstructionLength;
840

841
  // Validate that the function is hot patchable.
842
  size_t instruction_size = GetInstructionSize(old_func);
843
  if (instruction_size < kShortJumpInstructionLength ||
844
      !FunctionHasPadding(old_func, kHotPatchHeaderLen))
845
    return false;
846

847
  if (orig_old_func) {
848
    // Put the needed instructions into the trampoline bytes.
849
    uptr trampoline_length = instruction_size + kDirectBranchLength;
850
    uptr trampoline = AllocateMemoryForTrampoline(old_func, trampoline_length);
851
    if (!trampoline)
852
      return false;
853
    if (!CopyInstructions(trampoline, old_func, instruction_size))
854
      return false;
855
    WriteDirectBranch(trampoline + instruction_size,
856
                      old_func + instruction_size);
857
    *orig_old_func = trampoline;
858
  }
859

860
  // If needed, get memory space for indirect address.
861
  uptr indirect_address = 0;
862
#if SANITIZER_WINDOWS64
863
  indirect_address = AllocateMemoryForTrampoline(old_func, kAddressLength);
864
  if (!indirect_address)
865
    return false;
866
#endif
867

868
  // Change memory protection to writable.
869
  DWORD protection = 0;
870
  if (!ChangeMemoryProtection(header, patch_length, &protection))
871
    return false;
872

873
  // Write jumps to the redirected function.
874
  WriteBranch(header, indirect_address, new_func);
875
  WriteShortJumpInstruction(old_func, header);
876

877
  // Restore previous memory protection.
878
  if (!RestoreMemoryProtection(header, patch_length, protection))
879
    return false;
880

881
  return true;
882
}
883

884
bool OverrideFunctionWithTrampoline(
885
    uptr old_func, uptr new_func, uptr *orig_old_func) {
886

887
  size_t instructions_length = kBranchLength;
888
  size_t padding_length = 0;
889
  uptr indirect_address = 0;
890

891
  if (orig_old_func) {
892
    // Find out the number of bytes of the instructions we need to copy
893
    // to the trampoline.
894
    instructions_length = RoundUpToInstrBoundary(kBranchLength, old_func);
895
    if (!instructions_length)
896
      return false;
897

898
    // Put the needed instructions into the trampoline bytes.
899
    uptr trampoline_length = instructions_length + kDirectBranchLength;
900
    uptr trampoline = AllocateMemoryForTrampoline(old_func, trampoline_length);
901
    if (!trampoline)
902
      return false;
903
    if (!CopyInstructions(trampoline, old_func, instructions_length))
904
      return false;
905
    WriteDirectBranch(trampoline + instructions_length,
906
                      old_func + instructions_length);
907
    *orig_old_func = trampoline;
908
  }
909

910
#if SANITIZER_WINDOWS64
911
  // Check if the targeted address can be encoded in the function padding.
912
  // Otherwise, allocate it in the trampoline region.
913
  if (IsMemoryPadding(old_func - kAddressLength, kAddressLength)) {
914
    indirect_address = old_func - kAddressLength;
915
    padding_length = kAddressLength;
916
  } else {
917
    indirect_address = AllocateMemoryForTrampoline(old_func, kAddressLength);
918
    if (!indirect_address)
919
      return false;
920
  }
921
#endif
922

923
  // Change memory protection to writable.
924
  uptr patch_address = old_func - padding_length;
925
  uptr patch_length = instructions_length + padding_length;
926
  DWORD protection = 0;
927
  if (!ChangeMemoryProtection(patch_address, patch_length, &protection))
928
    return false;
929

930
  // Patch the original function.
931
  WriteBranch(old_func, indirect_address, new_func);
932

933
  // Restore previous memory protection.
934
  if (!RestoreMemoryProtection(patch_address, patch_length, protection))
935
    return false;
936

937
  return true;
938
}
939

940
bool OverrideFunction(
941
    uptr old_func, uptr new_func, uptr *orig_old_func) {
942
#if !SANITIZER_WINDOWS64
943
  if (OverrideFunctionWithDetour(old_func, new_func, orig_old_func))
944
    return true;
945
#endif
946
  if (OverrideFunctionWithRedirectJump(old_func, new_func, orig_old_func))
947
    return true;
948
  if (OverrideFunctionWithHotPatch(old_func, new_func, orig_old_func))
949
    return true;
950
  if (OverrideFunctionWithTrampoline(old_func, new_func, orig_old_func))
951
    return true;
952
  return false;
953
}
954

955
static void **InterestingDLLsAvailable() {
956
  static const char *InterestingDLLs[] = {
957
    "kernel32.dll",
958
    "msvcr100d.dll",      // VS2010
959
    "msvcr110d.dll",      // VS2012
960
    "msvcr120d.dll",      // VS2013
961
    "vcruntime140d.dll",  // VS2015
962
    "ucrtbased.dll",      // Universal CRT
963
    "msvcr100.dll",       // VS2010
964
    "msvcr110.dll",       // VS2012
965
    "msvcr120.dll",       // VS2013
966
    "vcruntime140.dll",   // VS2015
967
    "ucrtbase.dll",       // Universal CRT
968
#  if (defined(__MINGW32__) && defined(__i386__))
969
    "libc++.dll",     // libc++
970
    "libunwind.dll",  // libunwind
971
#  endif
972
    // NTDLL should go last as it exports some functions that we should
973
    // override in the CRT [presumably only used internally].
974
    "ntdll.dll",
975
    NULL
976
  };
977
  static void *result[ARRAY_SIZE(InterestingDLLs)] = { 0 };
978
  if (!result[0]) {
979
    for (size_t i = 0, j = 0; InterestingDLLs[i]; ++i) {
980
      if (HMODULE h = GetModuleHandleA(InterestingDLLs[i]))
981
        result[j++] = (void *)h;
982
    }
983
  }
984
  return &result[0];
985
}
986

987
namespace {
988
// Utility for reading loaded PE images.
989
template <typename T> class RVAPtr {
990
 public:
991
  RVAPtr(void *module, uptr rva)
992
      : ptr_(reinterpret_cast<T *>(reinterpret_cast<char *>(module) + rva)) {}
993
  operator T *() { return ptr_; }
994
  T *operator->() { return ptr_; }
995
  T *operator++() { return ++ptr_; }
996

997
 private:
998
  T *ptr_;
999
};
1000
} // namespace
1001

1002
// Internal implementation of GetProcAddress. At least since Windows 8,
1003
// GetProcAddress appears to initialize DLLs before returning function pointers
1004
// into them. This is problematic for the sanitizers, because they typically
1005
// want to intercept malloc *before* MSVCRT initializes. Our internal
1006
// implementation walks the export list manually without doing initialization.
1007
uptr InternalGetProcAddress(void *module, const char *func_name) {
1008
  // Check that the module header is full and present.
1009
  RVAPtr<IMAGE_DOS_HEADER> dos_stub(module, 0);
1010
  RVAPtr<IMAGE_NT_HEADERS> headers(module, dos_stub->e_lfanew);
1011
  if (!module || dos_stub->e_magic != IMAGE_DOS_SIGNATURE ||  // "MZ"
1012
      headers->Signature != IMAGE_NT_SIGNATURE ||             // "PE\0\0"
1013
      headers->FileHeader.SizeOfOptionalHeader <
1014
          sizeof(IMAGE_OPTIONAL_HEADER)) {
1015
    return 0;
1016
  }
1017

1018
  IMAGE_DATA_DIRECTORY *export_directory =
1019
      &headers->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT];
1020
  if (export_directory->Size == 0)
1021
    return 0;
1022
  RVAPtr<IMAGE_EXPORT_DIRECTORY> exports(module,
1023
                                         export_directory->VirtualAddress);
1024
  RVAPtr<DWORD> functions(module, exports->AddressOfFunctions);
1025
  RVAPtr<DWORD> names(module, exports->AddressOfNames);
1026
  RVAPtr<WORD> ordinals(module, exports->AddressOfNameOrdinals);
1027

1028
  for (DWORD i = 0; i < exports->NumberOfNames; i++) {
1029
    RVAPtr<char> name(module, names[i]);
1030
    if (!strcmp(func_name, name)) {
1031
      DWORD index = ordinals[i];
1032
      RVAPtr<char> func(module, functions[index]);
1033

1034
      // Handle forwarded functions.
1035
      DWORD offset = functions[index];
1036
      if (offset >= export_directory->VirtualAddress &&
1037
          offset < export_directory->VirtualAddress + export_directory->Size) {
1038
        // An entry for a forwarded function is a string with the following
1039
        // format: "<module> . <function_name>" that is stored into the
1040
        // exported directory.
1041
        char function_name[256];
1042
        size_t funtion_name_length = _strlen(func);
1043
        if (funtion_name_length >= sizeof(function_name) - 1)
1044
          InterceptionFailed();
1045

1046
        _memcpy(function_name, func, funtion_name_length);
1047
        function_name[funtion_name_length] = '\0';
1048
        char* separator = _strchr(function_name, '.');
1049
        if (!separator)
1050
          InterceptionFailed();
1051
        *separator = '\0';
1052

1053
        void* redirected_module = GetModuleHandleA(function_name);
1054
        if (!redirected_module)
1055
          InterceptionFailed();
1056
        return InternalGetProcAddress(redirected_module, separator + 1);
1057
      }
1058

1059
      return (uptr)(char *)func;
1060
    }
1061
  }
1062

1063
  return 0;
1064
}
1065

1066
bool OverrideFunction(
1067
    const char *func_name, uptr new_func, uptr *orig_old_func) {
1068
  bool hooked = false;
1069
  void **DLLs = InterestingDLLsAvailable();
1070
  for (size_t i = 0; DLLs[i]; ++i) {
1071
    uptr func_addr = InternalGetProcAddress(DLLs[i], func_name);
1072
    if (func_addr &&
1073
        OverrideFunction(func_addr, new_func, orig_old_func)) {
1074
      hooked = true;
1075
    }
1076
  }
1077
  return hooked;
1078
}
1079

1080
bool OverrideImportedFunction(const char *module_to_patch,
1081
                              const char *imported_module,
1082
                              const char *function_name, uptr new_function,
1083
                              uptr *orig_old_func) {
1084
  HMODULE module = GetModuleHandleA(module_to_patch);
1085
  if (!module)
1086
    return false;
1087

1088
  // Check that the module header is full and present.
1089
  RVAPtr<IMAGE_DOS_HEADER> dos_stub(module, 0);
1090
  RVAPtr<IMAGE_NT_HEADERS> headers(module, dos_stub->e_lfanew);
1091
  if (!module || dos_stub->e_magic != IMAGE_DOS_SIGNATURE ||  // "MZ"
1092
      headers->Signature != IMAGE_NT_SIGNATURE ||             // "PE\0\0"
1093
      headers->FileHeader.SizeOfOptionalHeader <
1094
          sizeof(IMAGE_OPTIONAL_HEADER)) {
1095
    return false;
1096
  }
1097

1098
  IMAGE_DATA_DIRECTORY *import_directory =
1099
      &headers->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT];
1100

1101
  // Iterate the list of imported DLLs. FirstThunk will be null for the last
1102
  // entry.
1103
  RVAPtr<IMAGE_IMPORT_DESCRIPTOR> imports(module,
1104
                                          import_directory->VirtualAddress);
1105
  for (; imports->FirstThunk != 0; ++imports) {
1106
    RVAPtr<const char> modname(module, imports->Name);
1107
    if (_stricmp(&*modname, imported_module) == 0)
1108
      break;
1109
  }
1110
  if (imports->FirstThunk == 0)
1111
    return false;
1112

1113
  // We have two parallel arrays: the import address table (IAT) and the table
1114
  // of names. They start out containing the same data, but the loader rewrites
1115
  // the IAT to hold imported addresses and leaves the name table in
1116
  // OriginalFirstThunk alone.
1117
  RVAPtr<IMAGE_THUNK_DATA> name_table(module, imports->OriginalFirstThunk);
1118
  RVAPtr<IMAGE_THUNK_DATA> iat(module, imports->FirstThunk);
1119
  for (; name_table->u1.Ordinal != 0; ++name_table, ++iat) {
1120
    if (!IMAGE_SNAP_BY_ORDINAL(name_table->u1.Ordinal)) {
1121
      RVAPtr<IMAGE_IMPORT_BY_NAME> import_by_name(
1122
          module, name_table->u1.ForwarderString);
1123
      const char *funcname = &import_by_name->Name[0];
1124
      if (strcmp(funcname, function_name) == 0)
1125
        break;
1126
    }
1127
  }
1128
  if (name_table->u1.Ordinal == 0)
1129
    return false;
1130

1131
  // Now we have the correct IAT entry. Do the swap. We have to make the page
1132
  // read/write first.
1133
  if (orig_old_func)
1134
    *orig_old_func = iat->u1.AddressOfData;
1135
  DWORD old_prot, unused_prot;
1136
  if (!VirtualProtect(&iat->u1.AddressOfData, 4, PAGE_EXECUTE_READWRITE,
1137
                      &old_prot))
1138
    return false;
1139
  iat->u1.AddressOfData = new_function;
1140
  if (!VirtualProtect(&iat->u1.AddressOfData, 4, old_prot, &unused_prot))
1141
    return false;  // Not clear if this failure bothers us.
1142
  return true;
1143
}
1144

1145
}  // namespace __interception
1146

1147
#endif  // SANITIZER_APPLE
1148

1149
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