Local NTP: Deploy strict-dynamic CSP

chrome/browser/search/local_ntp_source.cc

Index: chrome/browser/search/local_ntp_source.cc
diff --git a/chrome/browser/search/local_ntp_source.cc b/chrome/browser/search/local_ntp_source.cc
index 4388e6a087d92e4c31ea3e1b8a9f11f371836eb7..e14c748db04e45b4697b3fdaa4844f29535a153f 100644
--- a/chrome/browser/search/local_ntp_source.cc
+++ b/chrome/browser/search/local_ntp_source.cc
@@ -8,19 +8,20 @@
 
 #include <memory>
 
+#include "base/base64.h"
 #include "base/command_line.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted_memory.h"
-#include "base/metrics/field_trial.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/values.h"
 #include "build/build_config.h"
+#include "chrome/browser/search/google_search_provider_service.h"
+#include "chrome/browser/search/google_search_provider_service_factory.h"
 #include "chrome/browser/search/instant_io_context.h"
 #include "chrome/browser/search/local_files_ntp_source.h"
-#include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/themes/theme_properties.h"
 #include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/themes/theme_service_factory.h"
@@ -29,8 +30,9 @@
 #include "chrome/grit/browser_resources.h"
 #include "chrome/grit/generated_resources.h"
 #include "chrome/grit/theme_resources.h"
-#include "components/search_engines/template_url_service.h"
 #include "components/strings/grit/components_strings.h"
+#include "crypto/secure_hash.h"
+#include "net/base/hash_value.h"
 #include "net/url_request/url_request.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -46,13 +48,14 @@ const int kLocalResource = -1;
 
 const char kConfigDataFilename[] = "config.js";
 const char kThemeCSSFilename[] = "theme.css";
+const char kMainHtmlFilename[] = "local-ntp.html";
 
 const struct Resource{
   const char* filename;
   int identifier;
   const char* mime_type;
 } kResources[] = {
-    {"local-ntp.html", IDR_LOCAL_NTP_HTML, "text/html"},
+    {kMainHtmlFilename, kLocalResource, "text/html"},
     {"local-ntp.js", IDR_LOCAL_NTP_JS, "application/javascript"},
     {kConfigDataFilename, kLocalResource, "application/javascript"},
     {kThemeCSSFilename, kLocalResource, "text/css"},
@@ -67,23 +70,6 @@ std::string StripParameters(const std::string& path) {
   return path.substr(0, path.find("?"));
 }
 
-bool DefaultSearchProviderIsGoogle(Profile* profile) {
-  if (!profile)
-    return false;
-
-  TemplateURLService* template_url_service =
-      TemplateURLServiceFactory::GetForProfile(profile);
-  if (!template_url_service)
-    return false;
-
-  const TemplateURL* default_provider =
-      template_url_service->GetDefaultSearchProvider();
-  return default_provider &&
-      (default_provider->GetEngineType(
-          template_url_service->search_terms_data()) ==
-       SEARCH_ENGINE_GOOGLE);
-}
-
 // Adds a localized string keyed by resource id to the dictionary.
 void AddString(base::DictionaryValue* dictionary,
                const std::string& key,
@@ -116,9 +102,8 @@ std::unique_ptr<base::DictionaryValue> GetTranslatedStrings(bool is_google) {
 }
 
 // Returns a JS dictionary of configuration data for the local NTP.
-std::string GetConfigData(Profile* profile) {
+std::string GetConfigData(bool is_google) {
   base::DictionaryValue config_data;
-  bool is_google = DefaultSearchProviderIsGoogle(profile);
   config_data.Set("translatedStrings", GetTranslatedStrings(is_google));
   config_data.SetBoolean("isGooglePage", is_google);
 
@@ -134,6 +119,22 @@ std::string GetConfigData(Profile* profile) {
   return config_data_js;
 }
 
+std::string GetIntegritySha256Value(const std::string& data) {
+  // Compute the sha256 hash.
+  net::SHA256HashValue hash_value;
+  std::unique_ptr<crypto::SecureHash> hash(
+      crypto::SecureHash::Create(crypto::SecureHash::SHA256));
+  hash->Update(data.data(), data.size());
+  hash->Finish(&hash_value, sizeof(hash_value));
+
+  // Base64-encode it.
+  base::StringPiece hash_value_str(
+      reinterpret_cast<const char*>(hash_value.data), sizeof(hash_value));
+  std::string result;
+  base::Base64Encode(hash_value_str, &result);
+  return result;
+}
+
 std::string GetThemeCSS(Profile* profile) {
   SkColor background_color =
       ThemeService::GetThemeProviderForProfile(profile)
@@ -152,7 +153,18 @@ std::string GetLocalNtpPath() {
 
 }  // namespace
 
-LocalNtpSource::LocalNtpSource(Profile* profile) : profile_(profile) {}
+LocalNtpSource::LocalNtpSource(Profile* profile)
+    : profile_(profile),
+      default_search_provider_observer_(this),
+      default_search_provider_is_google_(false) {
+  GoogleSearchProviderService* google_service =
+      GoogleSearchProviderServiceFactory::GetForProfile(profile_);
+  if (google_service) {
+    default_search_provider_observer_.Add(google_service);
+    default_search_provider_is_google_ =
+        google_service->DefaultSearchProviderIsGoogle();
+  }
+}
 
 LocalNtpSource::~LocalNtpSource() = default;
 
@@ -166,7 +178,8 @@ void LocalNtpSource::StartDataRequest(
     const content::URLDataSource::GotDataCallback& callback) {
   std::string stripped_path = StripParameters(path);
   if (stripped_path == kConfigDataFilename) {
-    std::string config_data_js = GetConfigData(profile_);
+    std::string config_data_js =
+        GetConfigData(default_search_provider_is_google_);
     callback.Run(base::RefCountedString::TakeString(&config_data_js));
     return;
   }
@@ -188,6 +201,19 @@ void LocalNtpSource::StartDataRequest(
   }
 #endif  // !defined(GOOGLE_CHROME_BUILD)
 
+  if (stripped_path == kMainHtmlFilename) {
+    std::string html = ResourceBundle::GetSharedInstance()
+                           .GetRawDataResource(IDR_LOCAL_NTP_HTML)
+                           .as_string();
+    std::string config_sha256 =
+        "sha256-" + GetIntegritySha256Value(
+                        GetConfigData(default_search_provider_is_google_));
+    base::ReplaceFirstSubstringAfterOffset(&html, 0, "{{CONFIG_INTEGRITY}}",
+                                           config_sha256);
+    callback.Run(base::RefCountedString::TakeString(&html));
+    return;
+  }
+
   float scale = 1.0f;
   std::string filename;
   webui::ParsePathAndScale(
@@ -203,7 +229,7 @@ void LocalNtpSource::StartDataRequest(
       return;
     }
   }
-  callback.Run(NULL);
+  callback.Run(nullptr);
 }
 
 std::string LocalNtpSource::GetMimeType(
@@ -232,7 +258,7 @@ bool LocalNtpSource::ShouldServiceRequest(
 
   if (request->url().SchemeIs(chrome::kChromeSearchScheme)) {
     std::string filename;
-    webui::ParsePathAndScale(request->url(), &filename, NULL);
+    webui::ParsePathAndScale(request->url(), &filename, nullptr);
     for (size_t i = 0; i < arraysize(kResources); ++i) {
       if (filename == kResources[i].filename)
         return true;
@@ -241,8 +267,34 @@ bool LocalNtpSource::ShouldServiceRequest(
   return false;
 }
 
+std::string LocalNtpSource::GetContentSecurityPolicyScriptSrc() const {
+// Note: This method is called on the IO thread.
+#if !defined(GOOGLE_CHROME_BUILD)
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kLocalNtpReload)) {
+    // While live-editing the local NTP files, turn off CSP.
+    return "script-src *;";
+  }
+#endif  // !defined(GOOGLE_CHROME_BUILD)
+
+  return "script-src 'strict-dynamic' "
+         "'sha256-" +
+         GetIntegritySha256Value(
+             GetConfigData(default_search_provider_is_google_)) +
+         "' "
+         "'sha256-g38WaUaxnOIWY7E2LtLZ5ff9r5sn1dBj80jevt/kmx0=';";
+}
+
 std::string LocalNtpSource::GetContentSecurityPolicyChildSrc() const {
   // Allow embedding of most visited iframes.
   return base::StringPrintf("child-src %s;",
                             chrome::kChromeSearchMostVisitedUrl);
 }
+
+void LocalNtpSource::OnDefaultSearchProviderIsGoogleChanged(bool is_google) {
+  default_search_provider_is_google_ = is_google;

[sfiera, 2017/04/11 09:45:17]

What thread is this method called from? If it's the UI thread, and we're reading
it from (only?) the IO thread, shouldn't we send the write to the IO thread too?

[Marc Treib, 2017/04/11 12:37:59]

Threading in URLDataSource is kind of a mess :(  The ctor and StartDataRequest
are called on the UI thread, most of the other stuff on the IO thread. I've
added a bunch of DCHECK_CURRENTLY_ONs to make things clearer to the reader.

This method is called on the UI thread, but the bool is read on both UI and IO
thread, which is not quite safe :-/  I've added a copy of the variable for the
IO thread. I'm not particularly happy with this, it feels super fragile... an
std::atomic<bool> might have been nice, but that's banned (and also atomics are
generally discouraged). Better ideas welcome.

[sfiera, 2017/04/11 14:07:35]

Alright, thanks. This is ugly, but feels like the right thing to do given the
circumstances.

+}
+
+void LocalNtpSource::OnGoogleSearchProviderServiceShuttingDown() {
+  default_search_provider_observer_.RemoveAll();
+}