browser/app/winlauncher/SameBinary.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_SameBinary_h
   8 #define mozilla_SameBinary_h
   9
  10 #include "mozilla/WinHeaderOnlyUtils.h"
  11 #include "mozilla/NativeNt.h"
  12 #include "nsWindowsHelpers.h"
  13
  14 namespace mozilla {
  15
  16 class ProcessImagePath final {
  17   PathType mType;
  18   LauncherVoidResult mLastError;
  19
  20   // Using a larger buffer because an NT path may exceed MAX_PATH.
  21   WCHAR mPathBuffer[(MAX_PATH * 2) + 1];
  22
  23  public:
  24   // Initialize with an NT path string of a given process handle
  25   explicit ProcessImagePath(const nsAutoHandle& aProcess)
  26       : mType(PathType::eNtPath), mLastError(Ok()) {
  27     DWORD len = std::size(mPathBuffer);
  28     if (!::QueryFullProcessImageNameW(aProcess.get(), PROCESS_NAME_NATIVE,
  29                                       mPathBuffer, &len)) {
  30       mLastError = LAUNCHER_ERROR_FROM_LAST();
  31       return;
  32     }
  33   }
  34
  35   // Initizlize with a DOS path string of a given imagebase address
  36   explicit ProcessImagePath(HMODULE aImageBase)
  37       : mType(PathType::eDosPath), mLastError(Ok()) {
  38     DWORD len =
  39         ::GetModuleFileNameW(aImageBase, mPathBuffer, std::size(mPathBuffer));
  40     if (!len || len == std::size(mPathBuffer)) {
  41       mLastError = LAUNCHER_ERROR_FROM_LAST();
  42       return;
  43     }
  44   }
  45
  46   bool IsError() const { return mLastError.isErr(); }
  47
  48   const WindowsErrorType& GetError() const { return mLastError.inspectErr(); }
  49
  50   FileUniqueId GetId() const { return FileUniqueId(mPathBuffer, mType); }
  51
  52   bool CompareNtPaths(const ProcessImagePath& aOther) const {
  53     if (mLastError.isErr() || aOther.mLastError.isErr() ||
  54         mType != PathType::eNtPath || aOther.mType != PathType::eNtPath) {
  55       return false;
  56     }
  57
  58     UNICODE_STRING path1, path2;
  59     ::RtlInitUnicodeString(&path1, mPathBuffer);
  60     ::RtlInitUnicodeString(&path2, aOther.mPathBuffer);
  61     return !!::RtlEqualUnicodeString(&path1, &path2, TRUE);
  62   }
  63 };
  64
  65 enum class ImageFileCompareOption {
  66   Default,
  67   CompareNtPathsOnly,
  68 };
  69
  70 static inline mozilla::LauncherResult<bool> IsSameBinaryAsParentProcess(
  71     ImageFileCompareOption aOption = ImageFileCompareOption::Default) {
  72   mozilla::LauncherResult<DWORD> parentPid = mozilla::nt::GetParentProcessId();
  73   if (parentPid.isErr()) {
  74     return parentPid.propagateErr();
  75   }
  76
  77   nsAutoHandle parentProcess(::OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION,
  78                                            FALSE, parentPid.unwrap()));
  79   if (!parentProcess.get()) {
  80     DWORD err = ::GetLastError();
  81     if (err == ERROR_INVALID_PARAMETER || err == ERROR_ACCESS_DENIED) {
  82       // In the ERROR_INVALID_PARAMETER case, the process identified by
  83       // parentPid has already exited. This is a common case when the parent
  84       // process is not Firefox, thus we should return false instead of erroring
  85       // out.
  86       // The ERROR_ACCESS_DENIED case can happen when the parent process is
  87       // something that we don't have permission to query. For example, we may
  88       // encounter this when Firefox is launched by the Windows Task Scheduler.
  89       return false;
  90     }
  91
  92     return LAUNCHER_ERROR_FROM_WIN32(err);
  93   }
  94
  95   ProcessImagePath parentExe(parentProcess);
  96   if (parentExe.IsError()) {
  97     return ::mozilla::Err(parentExe.GetError());
  98   }
  99
 100   if (aOption == ImageFileCompareOption::Default) {
 101     bool skipFileIdComparison = false;
 102
 103     FileUniqueId id1 = parentExe.GetId();
 104     if (id1.IsError()) {
 105       // We saw a number of Win7 users failed to call NtOpenFile with
 106       // STATUS_OBJECT_PATH_NOT_FOUND for an unknown reason.  In this
 107       // particular case, we fall back to the logic to compare NT path
 108       // strings instead of a file id which will not fail because we don't
 109       // need to open a file handle.
 110 #if !defined(STATUS_OBJECT_PATH_NOT_FOUND)
 111       constexpr NTSTATUS STATUS_OBJECT_PATH_NOT_FOUND = 0xc000003a;
 112 #endif
 113       const LauncherError& err = id1.GetError();
 114       if (err.mError !=
 115           WindowsError::FromNtStatus(STATUS_OBJECT_PATH_NOT_FOUND)) {
 116         return ::mozilla::Err(err);
 117       }
 118
 119       skipFileIdComparison = true;
 120     }
 121
 122     if (!skipFileIdComparison) {
 123       ProcessImagePath ourExe(nullptr);
 124       if (ourExe.IsError()) {
 125         return ::mozilla::Err(ourExe.GetError());
 126       }
 127
 128       FileUniqueId id2 = ourExe.GetId();
 129       if (id2.IsError()) {
 130         return ::mozilla::Err(id2.GetError());
 131       }
 132       return id1 == id2;
 133     }
 134   }
 135
 136   nsAutoHandle ourProcess(::GetCurrentProcess());
 137   ProcessImagePath ourExeNt(ourProcess);
 138   if (ourExeNt.IsError()) {
 139     return ::mozilla::Err(ourExeNt.GetError());
 140   }
 141   return parentExe.CompareNtPaths(ourExeNt);
 142 }
 143
 144 }  // namespace mozilla
 145
 146 #endif  //  mozilla_SameBinary_h