Prevent extension sideloading from Windows registry

chrome/browser/extensions/external_registry_loader_win.cc

Index: chrome/browser/extensions/external_registry_loader_win.cc
diff --git a/chrome/browser/extensions/external_registry_loader_win.cc b/chrome/browser/extensions/external_registry_loader_win.cc
index c5f10a4dc1ce766dbdef9afbbb17d273baba4b44..6de5441b11d1e483defa41dd3126ba90931501d7 100644
--- a/chrome/browser/extensions/external_registry_loader_win.cc
+++ b/chrome/browser/extensions/external_registry_loader_win.cc
@@ -10,6 +10,7 @@
 #include "base/files/scoped_file.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "base/values.h"
@@ -43,6 +44,11 @@ bool CanOpenFileForReading(const base::FilePath& path) {
   return file_handle.get() != NULL;
 }
 
+std::string MakePrefName(const std::string& extension_id,
+                         const std::string& pref_name) {
+  return base::StringPrintf("%s.%s", extension_id.c_str(), pref_name.c_str());
+}
+
 }  // namespace
 
 namespace extensions {
@@ -100,7 +106,7 @@ void ExternalRegistryLoader::LoadOnFileThread() {
     base::string16 extension_dist_id;
     if (key.ReadValue(kRegistryExtensionInstallParam, &extension_dist_id) ==
         ERROR_SUCCESS) {
-      prefs->SetString(id + "." + ExternalProviderImpl::kInstallParam,
+      prefs->SetString(MakePrefName(id, ExternalProviderImpl::kInstallParam),
                        base::UTF16ToASCII(extension_dist_id));
     }
 
@@ -110,7 +116,7 @@ void ExternalRegistryLoader::LoadOnFileThread() {
     if (key.ReadValue(kRegistryExtensionUpdateUrl, &extension_update_url)
         == ERROR_SUCCESS) {
       prefs->SetString(
-          id + "." + ExternalProviderImpl::kExternalUpdateUrl,
+          MakePrefName(id, ExternalProviderImpl::kExternalUpdateUrl),
           base::UTF16ToASCII(extension_update_url));
       continue;
     }
@@ -164,11 +170,14 @@ void ExternalRegistryLoader::LoadOnFileThread() {
     }
 
     prefs->SetString(
-        id + "." + ExternalProviderImpl::kExternalVersion,
+        MakePrefName(id, ExternalProviderImpl::kExternalVersion),
         base::UTF16ToASCII(extension_version));
     prefs->SetString(
-        id + "." + ExternalProviderImpl::kExternalCrx,
+        MakePrefName(id, ExternalProviderImpl::kExternalCrx),
         extension_path_str);
+    prefs->SetBoolean(
+        MakePrefName(id, ExternalProviderImpl::kMayBeUntrusted),
+        true);
   }
 
   prefs_.reset(prefs.release());