зеркало из https://github.com/mozilla/gecko-dev.git
95 строки
3.6 KiB
C++
95 строки
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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#include "mozilla/NativeNt.h"
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#include "mozilla/WinHeaderOnlyUtils.h"
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namespace mozilla {
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namespace detail {
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inline LauncherResult<nt::DataDirectoryEntry> GetImageDirectoryViaFileIo(
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const nsAutoHandle& aImageFile, const uint32_t aOurImportDirectoryRva) {
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OVERLAPPED ov = {};
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ov.Offset = aOurImportDirectoryRva;
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DWORD bytesRead;
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nt::DataDirectoryEntry result;
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if (!::ReadFile(aImageFile, &result, sizeof(result), &bytesRead, &ov) ||
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bytesRead != sizeof(result)) {
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return LAUNCHER_ERROR_FROM_LAST();
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}
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return result;
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}
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} // namespace detail
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/**
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* This function ensures that the import directory of a loaded binary image
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* matches the version that is found in the original file on disk. We do this
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* to prevent tampering by third-party code.
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*
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* Yes, this function may perform file I/O on the critical path during
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* startup. A mitigating factor here is that this function must be called
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* immediately after creating a process using the image specified by
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* |aFullImagePath|; by this point, the system has already paid the price of
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* pulling the image file's contents into the page cache.
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*
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* @param aFullImagePath Wide-character string containing the absolute path
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* to the binary whose import directory we are touching.
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* @param aTransferMgr Encapsulating the transfer from the current process to
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* the child process whose import table we are touching.
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*/
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inline LauncherVoidResult RestoreImportDirectory(
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const wchar_t* aFullImagePath, nt::CrossExecTransferManager& aTransferMgr) {
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uint32_t importDirEntryRva;
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PIMAGE_DATA_DIRECTORY importDirEntry =
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aTransferMgr.LocalPEHeaders().GetImageDirectoryEntryPtr(
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IMAGE_DIRECTORY_ENTRY_IMPORT, &importDirEntryRva);
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if (!importDirEntry) {
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return LAUNCHER_ERROR_FROM_WIN32(ERROR_BAD_EXE_FORMAT);
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}
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nsAutoHandle file(::CreateFileW(aFullImagePath, GENERIC_READ, FILE_SHARE_READ,
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nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
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nullptr));
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if (file.get() == INVALID_HANDLE_VALUE) {
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return LAUNCHER_ERROR_FROM_LAST();
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}
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// Why do we use file I/O here instead of a memory mapping? The simple reason
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// is that we do not want any kernel-mode drivers to start tampering with file
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// contents under the belief that the file is being mapped for execution.
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// Windows 8 supports creation of file mappings using the SEC_IMAGE_NO_EXECUTE
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// flag, which may help to mitigate this, but we might as well just support
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// a single implementation that works everywhere.
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LauncherResult<nt::DataDirectoryEntry> realImportDirectory =
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detail::GetImageDirectoryViaFileIo(file, importDirEntryRva);
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if (realImportDirectory.isErr()) {
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return realImportDirectory.propagateErr();
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}
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nt::DataDirectoryEntry toWrite = realImportDirectory.unwrap();
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{ // Scope for prot
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AutoVirtualProtect prot = aTransferMgr.Protect(
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importDirEntry, sizeof(IMAGE_DATA_DIRECTORY), PAGE_READWRITE);
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if (!prot) {
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return LAUNCHER_ERROR_FROM_MOZ_WINDOWS_ERROR(prot.GetError());
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}
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LauncherVoidResult writeResult = aTransferMgr.Transfer(
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importDirEntry, &toWrite, sizeof(IMAGE_DATA_DIRECTORY));
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if (writeResult.isErr()) {
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return writeResult.propagateErr();
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}
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}
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return Ok();
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}
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} // namespace mozilla
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