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Diffstat (limited to 'widget/windows/ShellHeaderOnlyUtils.h')
| -rw-r--r-- | widget/windows/ShellHeaderOnlyUtils.h | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/widget/windows/ShellHeaderOnlyUtils.h b/widget/windows/ShellHeaderOnlyUtils.h new file mode 100644 index 0000000000..ea95077fb3 --- /dev/null +++ b/widget/windows/ShellHeaderOnlyUtils.h @@ -0,0 +1,183 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_ShellHeaderOnlyUtils_h +#define mozilla_ShellHeaderOnlyUtils_h + +#if defined(LIBXUL) && !defined(UNICODE) +# error \ + "UNICODE not set - must be set to prevent compile failure in `comdef.h` due to us deleting `FormatMessage` when absent." +#endif + +#include "mozilla/WinHeaderOnlyUtils.h" + +#include <objbase.h> + +#include <exdisp.h> +#include <shldisp.h> +#include <shlobj.h> +#include <shlwapi.h> +#include <shobjidl.h> +#include <shtypes.h> +// NB: include this after shldisp.h so its macros do not conflict with COM +// interfaces defined by shldisp.h +#include <shellapi.h> +#include <type_traits> + +#include <comdef.h> +#include <comutil.h> + +#include "mozilla/RefPtr.h" +#include "mozilla/UniquePtr.h" + +namespace mozilla { + +/** + * Ask the current user's Desktop to ShellExecute on our behalf, thus causing + * the resulting launched process to inherit its security priviliges from + * Explorer instead of our process. + * + * This is useful in two scenarios, in particular: + * * We are running as an elevated user and we want to start something as the + * "normal" user; + * * We are starting a process that is incompatible with our process's + * process mitigation policies. By delegating to Explorer, the child process + * will not be affected by our process mitigations. + * + * Since this communication happens over DCOM, Explorer's COM DACL governs + * whether or not we can execute against it, thus avoiding privilege escalation. + */ +inline LauncherVoidResult ShellExecuteByExplorer(const _bstr_t& aPath, + const _variant_t& aArgs, + const _variant_t& aVerb, + const _variant_t& aWorkingDir, + const _variant_t& aShowCmd) { + // NB: Explorer may be a local server, not an inproc server + RefPtr<IShellWindows> shellWindows; + HRESULT hr = ::CoCreateInstance( + CLSID_ShellWindows, nullptr, CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER, + IID_IShellWindows, getter_AddRefs(shellWindows)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + // 1. Find the shell view for the desktop. + _variant_t loc(int(CSIDL_DESKTOP)); + _variant_t empty; + long hwnd; + RefPtr<IDispatch> dispDesktop; + hr = shellWindows->FindWindowSW(&loc, &empty, SWC_DESKTOP, &hwnd, + SWFO_NEEDDISPATCH, + getter_AddRefs(dispDesktop)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + if (hr == S_FALSE) { + // The call succeeded but the window was not found. + return LAUNCHER_ERROR_FROM_WIN32(ERROR_NOT_FOUND); + } + + RefPtr<IServiceProvider> servProv; + hr = dispDesktop->QueryInterface(IID_IServiceProvider, + getter_AddRefs(servProv)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + RefPtr<IShellBrowser> browser; + hr = servProv->QueryService(SID_STopLevelBrowser, IID_IShellBrowser, + getter_AddRefs(browser)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + RefPtr<IShellView> activeShellView; + hr = browser->QueryActiveShellView(getter_AddRefs(activeShellView)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + // 2. Get the automation object for the desktop. + RefPtr<IDispatch> dispView; + hr = activeShellView->GetItemObject(SVGIO_BACKGROUND, IID_IDispatch, + getter_AddRefs(dispView)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + RefPtr<IShellFolderViewDual> folderView; + hr = dispView->QueryInterface(IID_IShellFolderViewDual, + getter_AddRefs(folderView)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + // 3. Get the interface to IShellDispatch2 + RefPtr<IDispatch> dispShell; + hr = folderView->get_Application(getter_AddRefs(dispShell)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + RefPtr<IShellDispatch2> shellDisp; + hr = + dispShell->QueryInterface(IID_IShellDispatch2, getter_AddRefs(shellDisp)); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + // Passing the foreground privilege so that the shell can launch an + // application in the foreground. This fails with E_ACCESSDENIED if the + // current window is shown in the background. We keep a soft assert for + // the other failures to investigate how it happened. + hr = ::CoAllowSetForegroundWindow(shellDisp, nullptr); + MOZ_ASSERT(SUCCEEDED(hr) || hr == E_ACCESSDENIED); + + // shellapi.h macros interfere with the correct naming of the method being + // called on IShellDispatch2. Temporarily remove that definition. +#if defined(ShellExecute) +# define MOZ_REDEFINE_SHELLEXECUTE +# undef ShellExecute +#endif // defined(ShellExecute) + + // 4. Now call IShellDispatch2::ShellExecute to ask Explorer to execute. + hr = shellDisp->ShellExecute(aPath, aArgs, aWorkingDir, aVerb, aShowCmd); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + // Restore the macro that was removed prior to IShellDispatch2::ShellExecute +#if defined(MOZ_REDEFINE_SHELLEXECUTE) +# if defined(UNICODE) +# define ShellExecute ShellExecuteW +# else +# define ShellExecute ShellExecuteA +# endif +# undef MOZ_REDEFINE_SHELLEXECUTE +#endif // defined(MOZ_REDEFINE_SHELLEXECUTE) + + return Ok(); +} + +using UniqueAbsolutePidl = + UniquePtr<std::remove_pointer_t<PIDLIST_ABSOLUTE>, CoTaskMemFreeDeleter>; + +inline LauncherResult<UniqueAbsolutePidl> ShellParseDisplayName( + const wchar_t* aPath) { + PIDLIST_ABSOLUTE rawAbsPidl = nullptr; + SFGAOF sfgao; + HRESULT hr = ::SHParseDisplayName(aPath, nullptr, &rawAbsPidl, 0, &sfgao); + if (FAILED(hr)) { + return LAUNCHER_ERROR_FROM_HRESULT(hr); + } + + return UniqueAbsolutePidl(rawAbsPidl); +} + +} // namespace mozilla + +#endif // mozilla_ShellHeaderOnlyUtils_h |