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

chrome_frame/chrome_launcher.cc

Index: chrome_frame/chrome_launcher.cc
diff --git a/chrome_frame/chrome_launcher.cc b/chrome_frame/chrome_launcher.cc
index f1a973309502a1b6b2acbd3fc721eb09aaeb5b2c..4379fe7a337b24e3b96a9250f2791186f3e2cb2c 100644
--- a/chrome_frame/chrome_launcher.cc
+++ b/chrome_frame/chrome_launcher.cc
@@ -8,6 +8,8 @@
 #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.
@@ -140,6 +142,57 @@ bool IsValidCommandLine(const wchar_t* command_line) {
   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)) {
@@ -157,6 +210,9 @@ bool SanitizeAndLaunchChrome(const wchar_t* command_line) {
         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;