Refactor and fix declarative webRequest API permissions

chrome/browser/extensions/api/web_request/web_request_permissions.cc

Index: chrome/browser/extensions/api/web_request/web_request_permissions.cc
diff --git a/chrome/browser/extensions/api/web_request/web_request_permissions.cc b/chrome/browser/extensions/api/web_request/web_request_permissions.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ca84616cef269801c45ad9761d46ccdcb5c36387
--- /dev/null
+++ b/chrome/browser/extensions/api/web_request/web_request_permissions.cc
@@ -0,0 +1,105 @@
+// 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/browser/extensions/api/web_request/web_request_permissions.h"
+
+#include "base/string_util.h"
+#include "base/stringprintf.h"
+#include "chrome/browser/extensions/extension_info_map.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/url_constants.h"
+#include "googleurl/src/gurl.h"
+#include "net/url_request/url_request.h"
+
+namespace {
+
+// Returns true if the URL is sensitive and requests to this URL must not be
+// modified/canceled by extensions, e.g. because it is targeted to the webstore
+// to check for updates, extension blacklisting, etc.
+bool IsSensitiveURL(const GURL& url) {
+  // TODO(battre) Merge this, CanExtensionAccessURL of web_request_api.cc and
+  // Extension::CanExecuteScriptOnPage into one function.
+  bool is_webstore_gallery_url =
+      StartsWithASCII(url.spec(), extension_urls::kGalleryBrowsePrefix, true);
+  bool sensitive_chrome_url = false;
+  if (EndsWith(url.host(), "google.com", true)) {
+    sensitive_chrome_url |= (url.host() == "www.google.com") &&
+                            StartsWithASCII(url.path(), "/chrome", true);
+    sensitive_chrome_url |= (url.host() == "chrome.google.com");
+    if (StartsWithASCII(url.host(), "client", true)) {
+      for (int i = 0; i < 10; ++i) {
+        sensitive_chrome_url |=
+            (StringPrintf("client%d.google.com", i) == url.host());
+      }
+    }
+  }
+  GURL::Replacements replacements;
+  replacements.ClearQuery();
+  replacements.ClearRef();
+  GURL url_without_query = url.ReplaceComponents(replacements);
+  return is_webstore_gallery_url || sensitive_chrome_url ||
+      extension_urls::IsWebstoreUpdateUrl(url_without_query) ||
+      extension_urls::IsBlacklistUpdateUrl(url);
+}
+
+// Returns true if the scheme is one we want to allow extensions to have access
+// to. Extensions still need specific permissions for a given URL, which is
+// covered by CanExtensionAccessURL.
+bool HasWebRequestScheme(const GURL& url) {
+  return (url.SchemeIs(chrome::kAboutScheme) ||
+          url.SchemeIs(chrome::kFileScheme) ||
+          url.SchemeIs(chrome::kFileSystemScheme) ||
+          url.SchemeIs(chrome::kFtpScheme) ||
+          url.SchemeIs(chrome::kHttpScheme) ||
+          url.SchemeIs(chrome::kHttpsScheme) ||
+          url.SchemeIs(chrome::kExtensionScheme));
+}
+
+}  // namespace
+
+// static
+bool WebRequestPermissions::HideRequest(const net::URLRequest* request) {
+  const GURL& url = request->url();
+  const GURL& first_party_url = request->first_party_for_cookies();
+  bool hide = false;
+  if (first_party_url.is_valid()) {
+    hide = IsSensitiveURL(first_party_url) ||
+           !HasWebRequestScheme(first_party_url);
+  }
+  if (!hide)
+    hide = IsSensitiveURL(url) || !HasWebRequestScheme(url);
+  return hide;
+}
+
+// static
+bool WebRequestPermissions::CanExtensionAccessURL(
+    const ExtensionInfoMap* extension_info_map,
+    const std::string& extension_id,
+    const GURL& url,
+    bool crosses_incognito,
+    bool enforce_host_permissions) {
+  // extension_info_map can be NULL in testing.
+  if (!extension_info_map)
+    return true;
+
+  const extensions::Extension* extension =
+      extension_info_map->extensions().GetByID(extension_id);
+  if (!extension)
+    return false;
+
+  // Check if this event crosses incognito boundaries when it shouldn't.
+  if (crosses_incognito && !extension_info_map->CanCrossIncognito(extension))
+    return false;
+
+  if (enforce_host_permissions) {
+    // about: URLs are not covered in host permissions, but are allowed anyway.
+    bool host_permissions_ok = (url.SchemeIs(chrome::kAboutScheme) ||
+                                extension->HasHostPermission(url) ||
+                                url.GetOrigin() == extension->url());
+    if (!host_permissions_ok)
+      return false;
+  }
+
+  return true;
+}