Adding policy support to Chrome Frame's launcher so that additional parameters can be passed to Chr…

chrome_frame/chrome_launcher.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome_frame/chrome_launcher.h"
 
 #include <windows.h>
 #include <shellapi.h>
 #include <shlwapi.h>
 
+#include "policy/policy_constants.h"
+
 // Herein lies stuff selectively stolen from Chrome. We don't pull it in
 // directly because all of it results in many things we don't want being
 // included as well.
 namespace {
 
 // These are the switches we will allow (along with their values) in the
 // safe-for-Low-Integrity version of the Chrome command line.
 // Including the chrome switch files pulls in a bunch of dependencies sadly, so
 // we redefine things here:
 const wchar_t* kAllowedSwitches[] = {
@@ skipping 112 matching lines @@
     std::wstring trimmed_arg = TrimWhiteSpace(args[i]);
     if (!IsValidArgument(trimmed_arg.c_str())) {
       success = false;
       break;
     }
   }
 
   return success;
 }
 
+// Looks up optionally configured launch parameters for Chrome that may have
+// been set via group policy.
+void AppendAdditionalLaunchParameters(std::wstring* command_line) {
+  static const HKEY kRootKeys[] = {
+    HKEY_LOCAL_MACHINE,
+    HKEY_CURRENT_USER
+  };
+
+  std::wstring launch_params_value_name(
+      &policy::key::kAdditionalLaunchParameters[0],
+      &policy::key::kAdditionalLaunchParameters[
+          lstrlenA(policy::key::kAdditionalLaunchParameters)]);
+
+  // Used for basic checks since CreateProcess doesn't support command lines
+  // longer than 0x8000 characters. If we surpass that length, we do not add the
+  // additional parameters.  Because we need to add a space before the
+  // extra parameters, we use 0x7fff and not 0x8000.
+  const size_t kMaxChars = 0x7FFF - command_line->size();
+  HKEY key;
+  LONG result;
+  bool found = false;
+  for (int i = 0; !found && i < arraysize(kRootKeys); ++i) {
+    result = ::RegOpenKeyExW(kRootKeys[i], policy::kRegistryMandatorySubKey, 0,
+                             KEY_READ, &key);

[grt (UTC plus 2), 2012/03/27 20:00:43]

nit: you could use KEY_QUERY_VALUE here to request least required privs.

+    if (result == ERROR_SUCCESS) {
+      DWORD size = 0;
+      DWORD type = 0;
+      result = RegQueryValueExW(key, launch_params_value_name.c_str(),
+                                0, &type, NULL, &size);
+      if (result == ERROR_SUCCESS && type == REG_SZ && size > 0 &&
+          (size / sizeof(wchar_t)) < kMaxChars) {
+        // This size includes any terminating null character or characters
+        // unless the data was stored without them, so for safety we allocate
+        // one extra char and zero out the buffer.
+        wchar_t* value = new wchar_t[(size / sizeof(wchar_t)) + 1];
+        memset(value, 0, size + sizeof(wchar_t));
+        result = RegQueryValueExW(key, launch_params_value_name.c_str(), 0,
+                                  &type, reinterpret_cast<BYTE*>(&value[0]),
+                                  &size);
+        if (result == ERROR_SUCCESS) {
+          *command_line += L' ';
+          *command_line += value;
+          found = true;
+        }
+        delete [] value;
+      }
+      ::RegCloseKey(key);
+    }
+  }
+}
+
 bool SanitizeAndLaunchChrome(const wchar_t* command_line) {
   bool success = false;
   if (IsValidCommandLine(command_line)) {
     std::wstring chrome_path;
     if (GetChromeExecutablePath(&chrome_path)) {
       const wchar_t* args = PathGetArgs(command_line);
 
       // Build the command line string with the quoted path to chrome.exe.
       std::wstring command_line;
       command_line.reserve(chrome_path.size() + 2);
       command_line.append(1, L'\"').append(chrome_path).append(1, L'\"');
 
       if (args != NULL) {
         command_line += L' ';
         command_line += args;
       }
 
+      // Append parameters that might be set by group policy.
+      AppendAdditionalLaunchParameters(&command_line);
+
       STARTUPINFO startup_info = {0};
       startup_info.cb = sizeof(startup_info);
       startup_info.dwFlags = STARTF_USESHOWWINDOW;
       startup_info.wShowWindow = SW_SHOW;
       PROCESS_INFORMATION process_info = {0};
       if (CreateProcess(&chrome_path[0], &command_line[0],
                         NULL, NULL, FALSE, 0, NULL, NULL,
                         &startup_info, &process_info)) {
         // Close handles.
         CloseHandle(process_info.hThread);
@@ skipping 33 matching lines @@
     if (PathFileExists(cur_path)) {
       *chrome_path = cur_path;
       success = true;
     }
   }
 
   return success;
 }
 
 }  // namespace chrome_launcher