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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at */
#include "DOMSecurityMonitor.h"
#include "nsContentUtils.h"
#include "nsIChannel.h"
#include "nsILoadInfo.h"
#include "nsIPrincipal.h"
#include "nsIURI.h"
#include "nsJSUtils.h"
#include "mozilla/BasePrincipal.h"
#include "mozilla/StaticPrefs_dom.h"
/* static */
void DOMSecurityMonitor::AuditParsingOfHTMLXMLFragments(
nsIPrincipal* aPrincipal, const nsAString& aFragment) {
// if the fragment parser (e.g. innerHTML()) is not called in chrome: code
// or any of our about: pages, then there is nothing to do here.
if (!aPrincipal->IsSystemPrincipal() && !aPrincipal->SchemeIs("about")) {
// check if the fragment is empty, if so, we can return early.
if (aFragment.IsEmpty()) {
// check if there is a JS caller, if not, then we can can return early here
// because we only care about calls to the fragment parser (e.g. innerHTML)
// originating from JS code.
nsAutoString filename;
uint32_t lineNum = 0;
uint32_t columnNum = 0;
JSContext* cx = nsContentUtils::GetCurrentJSContext();
if (!cx ||
!nsJSUtils::GetCallingLocation(cx, filename, &lineNum, &columnNum)) {
// check if we should skip assertion. Please only ever set this pref to
// true if really needed for testing purposes.
if (mozilla::StaticPrefs::dom_security_skip_html_fragment_assertion()) {
* WARNING: Do not add any new entries to the htmlFragmentAllowlist
* withiout proper review from a dom:security peer!
static nsLiteralCString htmlFragmentAllowlist[] = {
// ------------------------------------------------------------------
// test pages
// ------------------------------------------------------------------
for (const nsLiteralCString& allowlistEntry : htmlFragmentAllowlist) {
if (StringBeginsWith(NS_ConvertUTF16toUTF8(filename), allowlistEntry)) {
nsAutoCString uriSpec;
// Ideally we should not call the fragment parser (e.g. innerHTML()) in
// chrome: code or any of our about: pages. If you hit that assertion,
// please do *not* add your filename to the allowlist above, but rather
// refactor your code.
"Do not call the fragment parser (e.g innerHTML()) in chrome code "
"or in about: pages, (uri: %s), (caller: %s, line: %d, col: %d), "
"(fragment: %s)",
uriSpec.get(), NS_ConvertUTF16toUTF8(filename).get(), lineNum,
columnNum, NS_ConvertUTF16toUTF8(aFragment).get());
/* static */
void DOMSecurityMonitor::AuditUseOfJavaScriptURI(nsIChannel* aChannel) {
nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
nsCOMPtr<nsIPrincipal> loadingPrincipal = loadInfo->GetLoadingPrincipal();
// We only ever have no loadingPrincipal in case of a new top-level load.
// The purpose of this assertion is to make sure we do not allow loading
// javascript: URIs in system privileged contexts. Hence there is nothing
// to do here in case there is no loadingPrincipal.
if (!loadingPrincipal) {
// if the javascript: URI is not loaded by a system privileged context
// or an about: page, there there is nothing to do here.
if (!loadingPrincipal->IsSystemPrincipal() &&
!loadingPrincipal->SchemeIs("about")) {
"Do not use javascript: URIs in chrome code or in about: pages");