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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 http://mozilla.org/MPL/2.0/. */

#include "nsScriptSecurityManager.h"

#include "mozilla/ArrayUtils.h"

#include "xpcpublic.h"
#include "XPCWrapper.h"
#include "nsIInputStreamChannel.h"
#include "nsILoadContext.h"
#include "nsIServiceManager.h"
#include "nsIScriptObjectPrincipal.h"
#include "nsIScriptContext.h"
#include "nsIURL.h"
#include "nsIURIMutator.h"
#include "nsINestedURI.h"
#include "nspr.h"
#include "nsJSPrincipals.h"
#include "mozilla/BasePrincipal.h"
#include "ExpandedPrincipal.h"
#include "SystemPrincipal.h"
#include "NullPrincipal.h"
#include "DomainPolicy.h"
#include "nsString.h"
#include "nsCRT.h"
#include "nsCRTGlue.h"
#include "nsDocShell.h"
#include "nsError.h"
#include "nsDOMCID.h"
#include "nsTextFormatter.h"
#include "nsIStringBundle.h"
#include "nsNetUtil.h"
#include "nsIEffectiveTLDService.h"
#include "nsIProperties.h"
#include "nsDirectoryServiceDefs.h"
#include "nsIFile.h"
#include "nsIFileURL.h"
#include "nsIZipReader.h"
#include "nsIScriptGlobalObject.h"
#include "nsPIDOMWindow.h"
#include "nsIDocShell.h"
#include "nsIPrompt.h"
#include "nsIWindowWatcher.h"
#include "nsIConsoleService.h"
#include "nsIObserverService.h"
#include "nsIOService.h"
#include "nsIContent.h"
#include "nsDOMJSUtils.h"
#include "nsAboutProtocolUtils.h"
#include "nsIClassInfo.h"
#include "nsIURIFixup.h"
#include "nsCDefaultURIFixup.h"
#include "nsIChromeRegistry.h"
#include "nsIResProtocolHandler.h"
#include "nsIContentSecurityPolicy.h"
#include "nsIAsyncVerifyRedirectCallback.h"
#include "mozilla/Preferences.h"
#include "mozilla/dom/BindingUtils.h"
#include <stdint.h>
#include "mozilla/dom/ScriptSettings.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/StaticPtr.h"
#include "nsContentUtils.h"
#include "nsJSUtils.h"
#include "nsILoadInfo.h"
#include "nsIDOMXULCommandDispatcher.h"
#include "nsITreeSelection.h"

// This should be probably defined on some other place... but I couldn't find it
#define WEBAPPS_PERM_NAME "webapps-manage"

using namespace mozilla;
using namespace mozilla::dom;

nsIIOService* nsScriptSecurityManager::sIOService = nullptr;
nsIStringBundle* nsScriptSecurityManager::sStrBundle = nullptr;
JSContext* nsScriptSecurityManager::sContext = nullptr;
bool nsScriptSecurityManager::sStrictFileOriginPolicy = true;

///////////////////////////
// Convenience Functions //
///////////////////////////

class nsAutoInPrincipalDomainOriginSetter {
 public:
  nsAutoInPrincipalDomainOriginSetter() { ++sInPrincipalDomainOrigin; }
  ~nsAutoInPrincipalDomainOriginSetter() { --sInPrincipalDomainOrigin; }
  static uint32_t sInPrincipalDomainOrigin;
};
uint32_t nsAutoInPrincipalDomainOriginSetter::sInPrincipalDomainOrigin;

static nsresult GetOriginFromURI(nsIURI* aURI, nsACString& aOrigin) {
  if (nsAutoInPrincipalDomainOriginSetter::sInPrincipalDomainOrigin > 1) {
    // Allow a single recursive call to GetPrincipalDomainOrigin, since that
    // might be happening on a different principal from the first call.  But
    // after that, cut off the recursion; it just indicates that something
    // we're doing in this method causes us to reenter a security check here.
    return NS_ERROR_NOT_AVAILABLE;
  }

  nsAutoInPrincipalDomainOriginSetter autoSetter;

  nsCOMPtr<nsIURI> uri = NS_GetInnermostURI(aURI);
  NS_ENSURE_TRUE(uri, NS_ERROR_UNEXPECTED);

  nsAutoCString hostPort;

  nsresult rv = uri->GetHostPort(hostPort);
  if (NS_SUCCEEDED(rv)) {
    nsAutoCString scheme;
    rv = uri->GetScheme(scheme);
    NS_ENSURE_SUCCESS(rv, rv);
    aOrigin = scheme + NS_LITERAL_CSTRING("://") + hostPort;
  } else {
    // Some URIs (e.g., nsSimpleURI) don't support host. Just
    // get the full spec.
    rv = uri->GetSpec(aOrigin);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}

static nsresult GetPrincipalDomainOrigin(nsIPrincipal* aPrincipal,
                                         nsACString& aOrigin) {
  nsCOMPtr<nsIURI> uri;
  aPrincipal->GetDomain(getter_AddRefs(uri));
  if (!uri) {
    aPrincipal->GetURI(getter_AddRefs(uri));
  }
  NS_ENSURE_TRUE(uri, NS_ERROR_UNEXPECTED);

  return GetOriginFromURI(uri, aOrigin);
}

inline void SetPendingExceptionASCII(JSContext* cx, const char* aMsg) {
  JS_ReportErrorASCII(cx, "%s", aMsg);
}

inline void SetPendingException(JSContext* cx, const char16_t* aMsg) {
  NS_ConvertUTF16toUTF8 msg(aMsg);
  JS_ReportErrorUTF8(cx, "%s", msg.get());
}

/* static */
bool nsScriptSecurityManager::SecurityCompareURIs(nsIURI* aSourceURI,
                                                  nsIURI* aTargetURI) {
  return NS_SecurityCompareURIs(aSourceURI, aTargetURI,
                                sStrictFileOriginPolicy);
}

// SecurityHashURI is consistent with SecurityCompareURIs because
// NS_SecurityHashURI is consistent with NS_SecurityCompareURIs.  See
// nsNetUtil.h.
uint32_t nsScriptSecurityManager::SecurityHashURI(nsIURI* aURI) {
  return NS_SecurityHashURI(aURI);
}

/*
 * GetChannelResultPrincipal will return the principal that the resource
 * returned by this channel will use.  For example, if the resource is in
 * a sandbox, it will return the nullprincipal.  If the resource is forced
 * to inherit principal, it will return the principal of its parent.  If
 * the load doesn't require sandboxing or inheriting, it will return the same
 * principal as GetChannelURIPrincipal. Namely the principal of the URI
 * that is being loaded.
 */
NS_IMETHODIMP
nsScriptSecurityManager::GetChannelResultPrincipal(nsIChannel* aChannel,
                                                   nsIPrincipal** aPrincipal) {
  return GetChannelResultPrincipal(aChannel, aPrincipal,
                                   /*aIgnoreSandboxing*/ false);
}

nsresult nsScriptSecurityManager::GetChannelResultPrincipalIfNotSandboxed(
    nsIChannel* aChannel, nsIPrincipal** aPrincipal) {
  return GetChannelResultPrincipal(aChannel, aPrincipal,
                                   /*aIgnoreSandboxing*/ true);
}

static void InheritAndSetCSPOnPrincipalIfNeeded(nsIChannel* aChannel,
                                                nsIPrincipal* aPrincipal) {
  // loading a data: URI into an iframe, or loading frame[srcdoc] need
  // to inherit the CSP (see Bug 1073952, 1381761).
  MOZ_ASSERT(aChannel && aPrincipal, "need a valid channel and principal");
  if (!aChannel) {
    return;
  }

  nsCOMPtr<nsILoadInfo> loadInfo = aChannel->GetLoadInfo();
  if (!loadInfo || loadInfo->GetExternalContentPolicyType() !=
                       nsIContentPolicy::TYPE_SUBDOCUMENT) {
    return;
  }

  nsCOMPtr<nsIURI> uri;
  nsresult rv = aChannel->GetURI(getter_AddRefs(uri));
  NS_ENSURE_SUCCESS_VOID(rv);
  nsAutoCString URISpec;
  rv = uri->GetSpec(URISpec);
  NS_ENSURE_SUCCESS_VOID(rv);

  bool isSrcDoc = URISpec.EqualsLiteral("about:srcdoc");
  bool isData = (NS_SUCCEEDED(uri->SchemeIs("data", &isData)) && isData);

  if (!isSrcDoc && !isData) {
    return;
  }

  nsCOMPtr<nsIPrincipal> principalToInherit =
      loadInfo->FindPrincipalToInherit(aChannel);

  nsCOMPtr<nsIContentSecurityPolicy> originalCSP;
  principalToInherit->GetCsp(getter_AddRefs(originalCSP));
  if (!originalCSP) {
    return;
  }

  // if the principalToInherit had a CSP, add it to the before
  // created NullPrincipal (unless it already has one)
  MOZ_ASSERT(aPrincipal->GetIsNullPrincipal(),
             "inheriting the CSP only valid for NullPrincipal");
  nsCOMPtr<nsIContentSecurityPolicy> nullPrincipalCSP;
  aPrincipal->GetCsp(getter_AddRefs(nullPrincipalCSP));
  if (nullPrincipalCSP) {
    MOZ_ASSERT(nullPrincipalCSP == originalCSP,
               "There should be no other CSP here.");
    // CSPs are equal, no need to set it again.
    return;
  }
  aPrincipal->SetCsp(originalCSP);
}

nsresult nsScriptSecurityManager::GetChannelResultPrincipal(
    nsIChannel* aChannel, nsIPrincipal** aPrincipal, bool aIgnoreSandboxing) {
  NS_PRECONDITION(aChannel, "Must have channel!");
  // Check whether we have an nsILoadInfo that says what we should do.
  nsCOMPtr<nsILoadInfo> loadInfo = aChannel->GetLoadInfo();
  if (loadInfo && loadInfo->GetForceInheritPrincipalOverruleOwner()) {
    nsCOMPtr<nsIPrincipal> principalToInherit =
        loadInfo->FindPrincipalToInherit(aChannel);
    principalToInherit.forget(aPrincipal);
    return NS_OK;
  }

  nsCOMPtr<nsISupports> owner;
  aChannel->GetOwner(getter_AddRefs(owner));
  if (owner) {
    CallQueryInterface(owner, aPrincipal);
    if (*aPrincipal) {
      return NS_OK;
    }
  }

  if (loadInfo) {
    if (!aIgnoreSandboxing && loadInfo->GetLoadingSandboxed()) {
      MOZ_ALWAYS_TRUE(
          NS_SUCCEEDED(loadInfo->GetSandboxedLoadingPrincipal(aPrincipal)));
      MOZ_ASSERT(*aPrincipal);
      InheritAndSetCSPOnPrincipalIfNeeded(aChannel, *aPrincipal);
      return NS_OK;
    }

    bool forceInherit = loadInfo->GetForceInheritPrincipal();
    if (aIgnoreSandboxing && !forceInherit) {
      // Check if SEC_FORCE_INHERIT_PRINCIPAL was dropped because of
      // sandboxing:
      if (loadInfo->GetLoadingSandboxed() &&
          loadInfo->GetForceInheritPrincipalDropped()) {
        forceInherit = true;
      }
    }
    if (forceInherit) {
      nsCOMPtr<nsIPrincipal> principalToInherit =
          loadInfo->FindPrincipalToInherit(aChannel);
      principalToInherit.forget(aPrincipal);
      return NS_OK;
    }

    auto securityMode = loadInfo->GetSecurityMode();
    // The data: inheritance flags should only apply to the initial load,
    // not to loads that it might have redirected to.
    if (loadInfo->RedirectChain().IsEmpty() &&
        (securityMode == nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_INHERITS ||
         securityMode == nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS ||
         securityMode == nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS)) {
      nsCOMPtr<nsIURI> uri;
      nsresult rv = NS_GetFinalChannelURI(aChannel, getter_AddRefs(uri));
      NS_ENSURE_SUCCESS(rv, rv);

      nsCOMPtr<nsIPrincipal> principalToInherit =
          loadInfo->FindPrincipalToInherit(aChannel);
      bool inheritForAboutBlank = loadInfo->GetAboutBlankInherits();

      if (nsContentUtils::ChannelShouldInheritPrincipal(
              principalToInherit, uri, inheritForAboutBlank, false)) {
        principalToInherit.forget(aPrincipal);
        return NS_OK;
      }
    }
  }
  nsresult rv = GetChannelURIPrincipal(aChannel, aPrincipal);
  NS_ENSURE_SUCCESS(rv, rv);
  InheritAndSetCSPOnPrincipalIfNeeded(aChannel, *aPrincipal);
  return NS_OK;
}

/* The principal of the URI that this channel is loading. This is never
 * affected by things like sandboxed loads, or loads where we forcefully
 * inherit the principal.  Think of this as the principal of the server
 * which this channel is loading from.  Most callers should use
 * GetChannelResultPrincipal instead of GetChannelURIPrincipal.  Only
 * call GetChannelURIPrincipal if you are sure that you want the
 * principal that matches the uri, even in cases when the load is
 * sandboxed or when the load could be a blob or data uri (i.e even when
 * you encounter loads that may or may not be sandboxed and loads
 * that may or may not inherit)."
 */
NS_IMETHODIMP
nsScriptSecurityManager::GetChannelURIPrincipal(nsIChannel* aChannel,
                                                nsIPrincipal** aPrincipal) {
  NS_PRECONDITION(aChannel, "Must have channel!");

  // Get the principal from the URI.  Make sure this does the same thing
  // as nsDocument::Reset and XULDocument::StartDocumentLoad.
  nsCOMPtr<nsIURI> uri;
  nsresult rv = NS_GetFinalChannelURI(aChannel, getter_AddRefs(uri));
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsILoadInfo> loadInfo;
  aChannel->GetLoadInfo(getter_AddRefs(loadInfo));

  // Inherit the origin attributes from loadInfo.
  // If this is a top-level document load, the origin attributes of the
  // loadInfo will be set from nsDocShell::DoURILoad.
  // For subresource loading, the origin attributes of the loadInfo is from
  // its loadingPrincipal.
  OriginAttributes attrs;

  // For addons loadInfo might be null.
  if (loadInfo) {
    attrs = loadInfo->GetOriginAttributes();
  }

  nsCOMPtr<nsIPrincipal> prin =
      BasePrincipal::CreateCodebasePrincipal(uri, attrs);
  prin.forget(aPrincipal);
  return *aPrincipal ? NS_OK : NS_ERROR_FAILURE;
}

NS_IMETHODIMP
nsScriptSecurityManager::IsSystemPrincipal(nsIPrincipal* aPrincipal,
                                           bool* aIsSystem) {
  *aIsSystem = (aPrincipal == mSystemPrincipal);
  return NS_OK;
}

/////////////////////////////
// nsScriptSecurityManager //
/////////////////////////////

////////////////////////////////////
// Methods implementing ISupports //
////////////////////////////////////
NS_IMPL_ISUPPORTS(nsScriptSecurityManager, nsIScriptSecurityManager,
                  nsIObserver)

///////////////////////////////////////////////////
// Methods implementing nsIScriptSecurityManager //
///////////////////////////////////////////////////

///////////////// Security Checks /////////////////

bool nsScriptSecurityManager::ContentSecurityPolicyPermitsJSAction(
    JSContext* cx) {
  MOZ_ASSERT(cx == nsContentUtils::GetCurrentJSContext());
  nsCOMPtr<nsIPrincipal> subjectPrincipal = nsContentUtils::SubjectPrincipal();
  nsCOMPtr<nsIContentSecurityPolicy> csp;
  nsresult rv = subjectPrincipal->GetCsp(getter_AddRefs(csp));
  NS_ASSERTION(NS_SUCCEEDED(rv), "CSP: Failed to get CSP from principal.");

  // don't do anything unless there's a CSP
  if (!csp) return true;

  bool evalOK = true;
  bool reportViolation = false;
  rv = csp->GetAllowsEval(&reportViolation, &evalOK);

  if (NS_FAILED(rv)) {
    NS_WARNING("CSP: failed to get allowsEval");
    return true;  // fail open to not break sites.
  }

  if (reportViolation) {
    nsAutoString fileName;
    unsigned lineNum = 0;
    NS_NAMED_LITERAL_STRING(
        scriptSample, "call to eval() or related function blocked by CSP");

    JS::AutoFilename scriptFilename;
    if (JS::DescribeScriptedCaller(cx, &scriptFilename, &lineNum)) {
      if (const char* file = scriptFilename.get()) {
        CopyUTF8toUTF16(nsDependentCString(file), fileName);
      }
    } else {
      MOZ_ASSERT(!JS_IsExceptionPending(cx));
    }
    csp->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_EVAL,
                             fileName, scriptSample, lineNum, EmptyString(),
                             EmptyString());
  }

  return evalOK;
}

// static
bool nsScriptSecurityManager::JSPrincipalsSubsume(JSPrincipals* first,
                                                  JSPrincipals* second) {
  return nsJSPrincipals::get(first)->Subsumes(nsJSPrincipals::get(second));
}

NS_IMETHODIMP
nsScriptSecurityManager::CheckSameOriginURI(nsIURI* aSourceURI,
                                            nsIURI* aTargetURI,
                                            bool reportError) {
  if (!SecurityCompareURIs(aSourceURI, aTargetURI)) {
    if (reportError) {
      ReportError(nullptr, "CheckSameOriginError", aSourceURI, aTargetURI);
    }
    return NS_ERROR_DOM_BAD_URI;
  }
  return NS_OK;
}

/*static*/ uint32_t nsScriptSecurityManager::HashPrincipalByOrigin(
    nsIPrincipal* aPrincipal) {
  nsCOMPtr<nsIURI> uri;
  aPrincipal->GetDomain(getter_AddRefs(uri));
  if (!uri) aPrincipal->GetURI(getter_AddRefs(uri));
  return SecurityHashURI(uri);
}

NS_IMETHODIMP
nsScriptSecurityManager::CheckLoadURIFromScript(JSContext* cx, nsIURI* aURI) {
  // Get principal of currently executing script.
  MOZ_ASSERT(cx == nsContentUtils::GetCurrentJSContext());
  nsIPrincipal* principal = nsContentUtils::SubjectPrincipal();
  nsresult rv = CheckLoadURIWithPrincipal(principal, aURI,
                                          nsIScriptSecurityManager::STANDARD);
  if (NS_SUCCEEDED(rv)) {
    // OK to load
    return NS_OK;
  }

  // Report error.
  nsAutoCString spec;
  if (NS_FAILED(aURI->GetAsciiSpec(spec))) return NS_ERROR_FAILURE;
  nsAutoCString msg("Access to '");
  msg.Append(spec);
  msg.AppendLiteral("' from script denied");
  SetPendingExceptionASCII(cx, msg.get());
  return NS_ERROR_DOM_BAD_URI;
}

/**
 * Helper method to handle cases where a flag passed to
 * CheckLoadURIWithPrincipal means denying loading if the given URI has certain
 * nsIProtocolHandler flags set.
 * @return if success, access is allowed. Otherwise, deny access
 */
static nsresult DenyAccessIfURIHasFlags(nsIURI* aURI, uint32_t aURIFlags) {
  NS_PRECONDITION(aURI, "Must have URI!");

  bool uriHasFlags;
  nsresult rv = NS_URIChainHasFlags(aURI, aURIFlags, &uriHasFlags);
  NS_ENSURE_SUCCESS(rv, rv);

  if (uriHasFlags) {
    return NS_ERROR_DOM_BAD_URI;
  }

  return NS_OK;
}

static bool EqualOrSubdomain(nsIURI* aProbeArg, nsIURI* aBase) {
  nsresult rv;
  nsCOMPtr<nsIURI> probe = aProbeArg;

  nsCOMPtr<nsIEffectiveTLDService> tldService =
      do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID);
  NS_ENSURE_TRUE(tldService, false);
  while (true) {
    if (nsScriptSecurityManager::SecurityCompareURIs(probe, aBase)) {
      return true;
    }

    nsAutoCString host, newHost;
    rv = probe->GetHost(host);
    NS_ENSURE_SUCCESS(rv, false);

    rv = tldService->GetNextSubDomain(host, newHost);
    if (rv == NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS) {
      return false;
    }
    NS_ENSURE_SUCCESS(rv, false);
    rv = NS_MutateURI(probe).SetHost(newHost).Finalize(probe);
    NS_ENSURE_SUCCESS(rv, false);
  }
}

NS_IMETHODIMP
nsScriptSecurityManager::CheckLoadURIWithPrincipal(nsIPrincipal* aPrincipal,
                                                   nsIURI* aTargetURI,
                                                   uint32_t aFlags) {
  NS_PRECONDITION(aPrincipal,
                  "CheckLoadURIWithPrincipal must have a principal");
  // If someone passes a flag that we don't understand, we should
  // fail, because they may need a security check that we don't
  // provide.
  NS_ENSURE_FALSE(
      aFlags &
          ~(nsIScriptSecurityManager::LOAD_IS_AUTOMATIC_DOCUMENT_REPLACEMENT |
            nsIScriptSecurityManager::ALLOW_CHROME |
            nsIScriptSecurityManager::DISALLOW_SCRIPT |
            nsIScriptSecurityManager::DISALLOW_INHERIT_PRINCIPAL |
            nsIScriptSecurityManager::DONT_REPORT_ERRORS),
      NS_ERROR_UNEXPECTED);
  NS_ENSURE_ARG_POINTER(aPrincipal);
  NS_ENSURE_ARG_POINTER(aTargetURI);

  // If DISALLOW_INHERIT_PRINCIPAL is set, we prevent loading of URIs which
  // would do such inheriting. That would be URIs that do not have their own
  // security context. We do this even for the system principal.
  if (aFlags & nsIScriptSecurityManager::DISALLOW_INHERIT_PRINCIPAL) {
    nsresult rv = DenyAccessIfURIHasFlags(
        aTargetURI, nsIProtocolHandler::URI_INHERITS_SECURITY_CONTEXT);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (aPrincipal == mSystemPrincipal) {
    // Allow access
    return NS_OK;
  }

  nsCOMPtr<nsIURI> sourceURI;
  aPrincipal->GetURI(getter_AddRefs(sourceURI));
  if (!sourceURI) {
    auto* basePrin = BasePrincipal::Cast(aPrincipal);
    if (basePrin->Is<ExpandedPrincipal>()) {
      auto expanded = basePrin->As<ExpandedPrincipal>();
      for (auto& prin : expanded->WhiteList()) {
        nsresult rv = CheckLoadURIWithPrincipal(prin, aTargetURI, aFlags);
        if (NS_SUCCEEDED(rv)) {
          // Allow access if it succeeded with one of the white listed
          // principals
          return NS_OK;
        }
      }
      // None of our whitelisted principals worked.
      return NS_ERROR_DOM_BAD_URI;
    }
    NS_ERROR(
        "Non-system principals or expanded principal passed to "
        "CheckLoadURIWithPrincipal "
        "must have a URI!");
    return NS_ERROR_UNEXPECTED;
  }

  // Automatic loads are not allowed from certain protocols.
  if (aFlags &
      nsIScriptSecurityManager::LOAD_IS_AUTOMATIC_DOCUMENT_REPLACEMENT) {
    nsresult rv = DenyAccessIfURIHasFlags(
        sourceURI,
        nsIProtocolHandler::URI_FORBIDS_AUTOMATIC_DOCUMENT_REPLACEMENT);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  // If either URI is a nested URI, get the base URI
  nsCOMPtr<nsIURI> sourceBaseURI = NS_GetInnermostURI(sourceURI);
  nsCOMPtr<nsIURI> targetBaseURI = NS_GetInnermostURI(aTargetURI);

  //-- get the target scheme
  nsAutoCString targetScheme;
  nsresult rv = targetBaseURI->GetScheme(targetScheme);
  if (NS_FAILED(rv)) return rv;

  //-- Some callers do not allow loading javascript:
  if ((aFlags & nsIScriptSecurityManager::DISALLOW_SCRIPT) &&
      targetScheme.EqualsLiteral("javascript")) {
    return NS_ERROR_DOM_BAD_URI;
  }

  // Check for uris that are only loadable by principals that subsume them
  bool hasFlags;
  rv = NS_URIChainHasFlags(
      targetBaseURI, nsIProtocolHandler::URI_LOADABLE_BY_SUBSUMERS, &hasFlags);
  NS_ENSURE_SUCCESS(rv, rv);

  if (hasFlags) {
    // check nothing else in the URI chain has flags that prevent
    // access:
    rv = CheckLoadURIFlags(sourceURI, aTargetURI, sourceBaseURI, targetBaseURI,
                           aFlags);
    NS_ENSURE_SUCCESS(rv, rv);
    // Check the principal is allowed to load the target.
    return aPrincipal->CheckMayLoad(targetBaseURI, true, false);
  }

  //-- get the source scheme
  nsAutoCString sourceScheme;
  rv = sourceBaseURI->GetScheme(sourceScheme);
  if (NS_FAILED(rv)) return rv;

  // When comparing schemes, if the relevant pref is set, view-source URIs
  // are reachable from same-protocol (so e.g. file: can link to
  // view-source:file). This is required for reftests.
  static bool sViewSourceReachableFromInner = false;
  static bool sCachedViewSourcePref = false;
  if (!sCachedViewSourcePref) {
    sCachedViewSourcePref = true;
    mozilla::Preferences::AddBoolVarCache(
        &sViewSourceReachableFromInner,
        "security.view-source.reachable-from-inner-protocol");
  }

  bool targetIsViewSource = false;

  if (sourceScheme.LowerCaseEqualsLiteral(NS_NULLPRINCIPAL_SCHEME)) {
    // A null principal can target its own URI.
    if (sourceURI == aTargetURI) {
      return NS_OK;
    }
  } else if (sViewSourceReachableFromInner &&
             sourceScheme.EqualsIgnoreCase(targetScheme.get()) &&
             NS_SUCCEEDED(
                 aTargetURI->SchemeIs("view-source", &targetIsViewSource)) &&
             targetIsViewSource) {
    // exception for foo: linking to view-source:foo for reftests...
    return NS_OK;
  } else if (sourceScheme.EqualsIgnoreCase("file") &&
             targetScheme.EqualsIgnoreCase("moz-icon")) {
    // exception for file: linking to moz-icon://.ext?size=...
    // Note that because targetScheme is the base (innermost) URI scheme,
    // this does NOT allow file -> moz-icon:file:///... links.
    // This is intentional.
    return NS_OK;
  }

  // Check for webextension
  rv = NS_URIChainHasFlags(
      aTargetURI, nsIProtocolHandler::URI_LOADABLE_BY_EXTENSIONS, &hasFlags);
  NS_ENSURE_SUCCESS(rv, rv);

  if (hasFlags && BasePrincipal::Cast(aPrincipal)->AddonPolicy()) {
    return NS_OK;
  }

  // If we get here, check all the schemes can link to each other, from the top
  // down:
  nsCaseInsensitiveCStringComparator stringComparator;
  nsCOMPtr<nsIURI> currentURI = sourceURI;
  nsCOMPtr<nsIURI> currentOtherURI = aTargetURI;

  bool denySameSchemeLinks = false;
  rv = NS_URIChainHasFlags(aTargetURI,
                           nsIProtocolHandler::URI_SCHEME_NOT_SELF_LINKABLE,
                           &denySameSchemeLinks);
  if (NS_FAILED(rv)) return rv;

  while (currentURI && currentOtherURI) {
    nsAutoCString scheme, otherScheme;
    currentURI->GetScheme(scheme);
    currentOtherURI->GetScheme(otherScheme);

    bool schemesMatch = scheme.Equals(otherScheme, stringComparator);
    bool isSamePage = false;
    // about: URIs are special snowflakes.
    if (scheme.EqualsLiteral("about") && schemesMatch) {
      nsAutoCString moduleName, otherModuleName;
      // about: pages can always link to themselves:
      isSamePage =
          NS_SUCCEEDED(NS_GetAboutModuleName(currentURI, moduleName)) &&
          NS_SUCCEEDED(
              NS_GetAboutModuleName(currentOtherURI, otherModuleName)) &&
          moduleName.Equals(otherModuleName);
      if (!isSamePage) {
        // We will have allowed the load earlier if the source page has
        // system principal. So we know the source has a content
        // principal, and it's trying to link to something else.
        // Linkable about: pages are always reachable, even if we hit
        // the CheckLoadURIFlags call below.
        // We punch only 1 other hole: iff the source is unlinkable,
        // we let them link to other pages explicitly marked SAFE
        // for content. This avoids world-linkable about: pages linking
        // to non-world-linkable about: pages.
        nsCOMPtr<nsIAboutModule> module, otherModule;
        bool knowBothModules =
            NS_SUCCEEDED(
                NS_GetAboutModule(currentURI, getter_AddRefs(module))) &&
            NS_SUCCEEDED(NS_GetAboutModule(currentOtherURI,
                                           getter_AddRefs(otherModule)));
        uint32_t aboutModuleFlags = 0;
        uint32_t otherAboutModuleFlags = 0;
        knowBothModules =
            knowBothModules &&
            NS_SUCCEEDED(module->GetURIFlags(currentURI, &aboutModuleFlags)) &&
            NS_SUCCEEDED(otherModule->GetURIFlags(currentOtherURI,
                                                  &otherAboutModuleFlags));
        if (knowBothModules) {
          isSamePage = !(aboutModuleFlags & nsIAboutModule::MAKE_LINKABLE) &&
                       (otherAboutModuleFlags &
                        nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT);
          if (isSamePage &&
              otherAboutModuleFlags & nsIAboutModule::MAKE_LINKABLE) {
            // XXXgijs: this is a hack. The target will be nested
            // (with innerURI of moz-safe-about:whatever), and
            // the source isn't, so we won't pass if we finish
            // the loop. We *should* pass, though, so return here.
            // This hack can go away when bug 1228118 is fixed.
            return NS_OK;
          }
        }
      }
    } else {
      bool equalExceptRef = false;
      rv = currentURI->EqualsExceptRef(currentOtherURI, &equalExceptRef);
      isSamePage = NS_SUCCEEDED(rv) && equalExceptRef;
    }

    // If schemes are not equal, or they're equal but the target URI
    // is different from the source URI and doesn't always allow linking
    // from the same scheme, check if the URI flags of the current target
    // URI allow the current source URI to link to it.
    // The policy is specified by the protocol flags on both URIs.
    if (!schemesMatch || (denySameSchemeLinks && !isSamePage)) {
      return CheckLoadURIFlags(currentURI, currentOtherURI, sourceBaseURI,
                               targetBaseURI, aFlags);
    }
    // Otherwise... check if we can nest another level:
    nsCOMPtr<nsINestedURI> nestedURI = do_QueryInterface(currentURI);
    nsCOMPtr<nsINestedURI> nestedOtherURI = do_QueryInterface(currentOtherURI);

    // If schemes match and neither URI is nested further, we're OK.
    if (!nestedURI && !nestedOtherURI) {
      return NS_OK;
    }
    // If one is nested and the other isn't, something is wrong.
    if (!nestedURI != !nestedOtherURI) {
      return NS_ERROR_DOM_BAD_URI;
    }
    // Otherwise, both should be nested and we'll go through the loop again.
    nestedURI->GetInnerURI(getter_AddRefs(currentURI));
    nestedOtherURI->GetInnerURI(getter_AddRefs(currentOtherURI));
  }

  // We should never get here. We should always return from inside the loop.
  return NS_ERROR_DOM_BAD_URI;
}

/**
 * Helper method to check whether the target URI and its innermost ("base") URI
 * has protocol flags that should stop it from being loaded by the source URI
 * (and/or the source URI's innermost ("base") URI), taking into account any
 * nsIScriptSecurityManager flags originally passed to
 * CheckLoadURIWithPrincipal and friends.
 *
 * @return if success, access is allowed. Otherwise, deny access
 */
nsresult nsScriptSecurityManager::CheckLoadURIFlags(nsIURI* aSourceURI,
                                                    nsIURI* aTargetURI,
                                                    nsIURI* aSourceBaseURI,
                                                    nsIURI* aTargetBaseURI,
                                                    uint32_t aFlags) {
  // Note that the order of policy checks here is very important!
  // We start from most restrictive and work our way down.
  bool reportErrors = !(aFlags & nsIScriptSecurityManager::DONT_REPORT_ERRORS);
  const char* errorTag = "CheckLoadURIError";

  nsAutoCString targetScheme;
  nsresult rv = aTargetBaseURI->GetScheme(targetScheme);
  if (NS_FAILED(rv)) return rv;

  // Check for system target URI
  rv = DenyAccessIfURIHasFlags(aTargetURI,
                               nsIProtocolHandler::URI_DANGEROUS_TO_LOAD);
  if (NS_FAILED(rv)) {
    // Deny access, since the origin principal is not system
    if (reportErrors) {
      ReportError(nullptr, errorTag, aSourceURI, aTargetURI);
    }
    return rv;
  }

  // Check for chrome target URI
  bool hasFlags = false;
  rv = NS_URIChainHasFlags(aTargetURI, nsIProtocolHandler::URI_IS_UI_RESOURCE,
                           &hasFlags);
  NS_ENSURE_SUCCESS(rv, rv);
  if (hasFlags) {
    if (aFlags & nsIScriptSecurityManager::ALLOW_CHROME) {
      // Allow a URI_IS_UI_RESOURCE source to link to a URI_IS_UI_RESOURCE
      // target if ALLOW_CHROME is set.
      //
      // ALLOW_CHROME is a flag that we pass on all loads _except_ docshell
      // loads (since docshell loads run the loaded content with its origin
      // principal). So we're effectively allowing resource://, chrome://,
      // and moz-icon:// source URIs to load resource://, chrome://, and
      // moz-icon:// files, so long as they're not loading it as a document.
      bool sourceIsUIResource;
      rv = NS_URIChainHasFlags(aSourceBaseURI,
                               nsIProtocolHandler::URI_IS_UI_RESOURCE,
                               &sourceIsUIResource);
      NS_ENSURE_SUCCESS(rv, rv);
      if (sourceIsUIResource) {
        return NS_OK;
      }

      if (targetScheme.EqualsLiteral("resource")) {
        // Mochitests that need to load resource:// URIs not declared
        // content-accessible in manifests should set the preference
        // "security.all_resource_uri_content_accessible" true.
        static bool sSecurityPrefCached = false;
        static bool sAllResourceUriContentAccessible = false;
        if (!sSecurityPrefCached) {
          sSecurityPrefCached = true;
          Preferences::AddBoolVarCache(
              &sAllResourceUriContentAccessible,
              "security.all_resource_uri_content_accessible", false);
        }
        if (sAllResourceUriContentAccessible) {
          return NS_OK;
        }

        nsCOMPtr<nsIProtocolHandler> ph;
        rv = sIOService->GetProtocolHandler("resource", getter_AddRefs(ph));
        NS_ENSURE_SUCCESS(rv, rv);
        if (!ph) {
          return NS_ERROR_DOM_BAD_URI;
        }

        nsCOMPtr<nsIResProtocolHandler> rph = do_QueryInterface(ph);
        if (!rph) {
          return NS_ERROR_DOM_BAD_URI;
        }

        bool accessAllowed = false;
        rph->AllowContentToAccess(aTargetBaseURI, &accessAllowed);
        if (accessAllowed) {
          return NS_OK;
        }
      } else if (targetScheme.EqualsLiteral("chrome")) {
        // Allow the load only if the chrome package is whitelisted.
        nsCOMPtr<nsIXULChromeRegistry> reg(
            do_GetService(NS_CHROMEREGISTRY_CONTRACTID));
        if (reg) {
          bool accessAllowed = false;
          reg->AllowContentToAccess(aTargetBaseURI, &accessAllowed);
          if (accessAllowed) {
            return NS_OK;
          }
        }
      }
    }

    static bool sCanLoadChromeInContent = false;
    static bool sCachedCanLoadChromeInContentPref = false;
    if (!sCachedCanLoadChromeInContentPref) {
      sCachedCanLoadChromeInContentPref = true;
      mozilla::Preferences::AddBoolVarCache(
          &sCanLoadChromeInContent,
          "security.allow_chrome_frames_inside_content");
    }
    if (sCanLoadChromeInContent) {
      // Special-case the hidden window: it's allowed to load
      // URI_IS_UI_RESOURCE no matter what.  Bug 1145470 tracks removing this.
      nsAutoCString sourceSpec;
      if (NS_SUCCEEDED(aSourceBaseURI->GetSpec(sourceSpec)) &&
          sourceSpec.EqualsLiteral(
              "resource://gre-resources/hiddenWindow.html")) {
        return NS_OK;
      }
    }

    if (reportErrors) {
      ReportError(nullptr, errorTag, aSourceURI, aTargetURI);
    }
    return NS_ERROR_DOM_BAD_URI;
  }

  // Check for target URI pointing to a file
  rv = NS_URIChainHasFlags(aTargetURI, nsIProtocolHandler::URI_IS_LOCAL_FILE,
                           &hasFlags);
  NS_ENSURE_SUCCESS(rv, rv);
  if (hasFlags) {
    // Allow domains that were whitelisted in the prefs. In 99.9% of cases,
    // this array is empty.
    bool isWhitelisted;
    MOZ_ALWAYS_SUCCEEDS(InFileURIWhitelist(aSourceURI, &isWhitelisted));
    if (isWhitelisted) {
      return NS_OK;
    }

    // Allow chrome://
    bool isChrome = false;
    if (NS_SUCCEEDED(aSourceBaseURI->SchemeIs("chrome", &isChrome)) &&
        isChrome) {
      return NS_OK;
    }

    // Nothing else.
    if (reportErrors) {
      ReportError(nullptr, errorTag, aSourceURI, aTargetURI);
    }
    return NS_ERROR_DOM_BAD_URI;
  }

  // OK, everyone is allowed to load this, since unflagged handlers are
  // deprecated but treated as URI_LOADABLE_BY_ANYONE.  But check whether we
  // need to warn.  At some point we'll want to make this warning into an
  // error and treat unflagged handlers as URI_DANGEROUS_TO_LOAD.
  rv = NS_URIChainHasFlags(
      aTargetBaseURI, nsIProtocolHandler::URI_LOADABLE_BY_ANYONE, &hasFlags);
  NS_ENSURE_SUCCESS(rv, rv);
  // NB: we also get here if the base URI is URI_LOADABLE_BY_SUBSUMERS,
  // and none of the rest of the nested chain of URIs for aTargetURI
  // prohibits the load, so avoid warning in that case:
  bool hasSubsumersFlag = false;
  rv = NS_URIChainHasFlags(aTargetBaseURI,
                           nsIProtocolHandler::URI_LOADABLE_BY_SUBSUMERS,
                           &hasSubsumersFlag);
  NS_ENSURE_SUCCESS(rv, rv);
  if (!hasFlags && !hasSubsumersFlag) {
    nsAutoString message;
    NS_ConvertASCIItoUTF16 ucsTargetScheme(targetScheme);
    const char16_t* formatStrings[] = {ucsTargetScheme.get()};
    rv = sStrBundle->FormatStringFromName("ProtocolFlagError", formatStrings,
                                          ArrayLength(formatStrings), message);
    if (NS_SUCCEEDED(rv)) {
      nsCOMPtr<nsIConsoleService> console(
          do_GetService("@mozilla.org/consoleservice;1"));
      NS_ENSURE_TRUE(console, NS_ERROR_FAILURE);

      console->LogStringMessage(message.get());
    }
  }

  return NS_OK;
}

nsresult nsScriptSecurityManager::ReportError(JSContext* cx,
                                              const char* aMessageTag,
                                              nsIURI* aSource,
                                              nsIURI* aTarget) {
  nsresult rv;
  NS_ENSURE_TRUE(aSource && aTarget, NS_ERROR_NULL_POINTER);

  // Get the source URL spec
  nsAutoCString sourceSpec;
  rv = aSource->GetAsciiSpec(sourceSpec);
  NS_ENSURE_SUCCESS(rv, rv);

  // Get the target URL spec
  nsAutoCString targetSpec;
  rv = aTarget->GetAsciiSpec(targetSpec);
  NS_ENSURE_SUCCESS(rv, rv);

  // Localize the error message
  nsAutoString message;
  NS_ConvertASCIItoUTF16 ucsSourceSpec(sourceSpec);
  NS_ConvertASCIItoUTF16 ucsTargetSpec(targetSpec);
  const char16_t* formatStrings[] = {ucsSourceSpec.get(), ucsTargetSpec.get()};
  rv = sStrBundle->FormatStringFromName(aMessageTag, formatStrings,
                                        ArrayLength(formatStrings), message);
  NS_ENSURE_SUCCESS(rv, rv);

  // If a JS context was passed in, set a JS exception.
  // Otherwise, print the error message directly to the JS console
  // and to standard output
  if (cx) {
    SetPendingException(cx, message.get());
  } else  // Print directly to the console
  {
    nsCOMPtr<nsIConsoleService> console(
        do_GetService("@mozilla.org/consoleservice;1"));
    NS_ENSURE_TRUE(console, NS_ERROR_FAILURE);

    console->LogStringMessage(message.get());
  }
  return NS_OK;
}

NS_IMETHODIMP
nsScriptSecurityManager::CheckLoadURIStrWithPrincipal(
    nsIPrincipal* aPrincipal, const nsACString& aTargetURIStr,
    uint32_t aFlags) {
  nsresult rv;
  nsCOMPtr<nsIURI> target;
  rv = NS_NewURI(getter_AddRefs(target), aTargetURIStr, nullptr, nullptr,
                 sIOService);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = CheckLoadURIWithPrincipal(aPrincipal, target, aFlags);
  if (rv == NS_ERROR_DOM_BAD_URI) {
    // Don't warn because NS_ERROR_DOM_BAD_URI is one of the expected
    // return values.
    return rv;
  }
  NS_ENSURE_SUCCESS(rv, rv);

  // Now start testing fixup -- since aTargetURIStr is a string, not
  // an nsIURI, we may well end up fixing it up before loading.
  // Note: This needs to stay in sync with the nsIURIFixup api.
  nsCOMPtr<nsIURIFixup> fixup = do_GetService(NS_URIFIXUP_CONTRACTID);
  if (!fixup) {
    return rv;
  }

  uint32_t flags[] = {nsIURIFixup::FIXUP_FLAG_NONE,
                      nsIURIFixup::FIXUP_FLAG_FIX_SCHEME_TYPOS,
                      nsIURIFixup::FIXUP_FLAG_ALLOW_KEYWORD_LOOKUP,
                      nsIURIFixup::FIXUP_FLAGS_MAKE_ALTERNATE_URI,
                      nsIURIFixup::FIXUP_FLAG_ALLOW_KEYWORD_LOOKUP |
                          nsIURIFixup::FIXUP_FLAGS_MAKE_ALTERNATE_URI};

  for (uint32_t i = 0; i < ArrayLength(flags); ++i) {
    rv = fixup->CreateFixupURI(aTargetURIStr, flags[i], nullptr,
                               getter_AddRefs(target));
    NS_ENSURE_SUCCESS(rv, rv);

    rv = CheckLoadURIWithPrincipal(aPrincipal, target, aFlags);
    if (rv == NS_ERROR_DOM_BAD_URI) {
      // Don't warn because NS_ERROR_DOM_BAD_URI is one of the expected
      // return values.
      return rv;
    }
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return rv;
}

NS_IMETHODIMP
nsScriptSecurityManager::InFileURIWhitelist(nsIURI* aUri, bool* aResult) {
  MOZ_ASSERT(aUri);
  MOZ_ASSERT(aResult);

  *aResult = false;
  for (nsIURI* uri : EnsureFileURIWhitelist()) {
    if (EqualOrSubdomain(aUri, uri)) {
      *aResult = true;
      return NS_OK;
    }
  }

  return NS_OK;
}

///////////////// Principals ///////////////////////

NS_IMETHODIMP
nsScriptSecurityManager::GetSystemPrincipal(nsIPrincipal** result) {
  NS_ADDREF(*result = mSystemPrincipal);

  return NS_OK;
}

NS_IMETHODIMP
nsScriptSecurityManager::CreateCodebasePrincipal(
    nsIURI* aURI, JS::Handle<JS::Value> aOriginAttributes, JSContext* aCx,
    nsIPrincipal** aPrincipal) {
  OriginAttributes attrs;
  if (!aOriginAttributes.isObject() || !attrs.Init(aCx, aOriginAttributes)) {
    return NS_ERROR_INVALID_ARG;
  }
  nsCOMPtr<nsIPrincipal> prin =
      BasePrincipal::CreateCodebasePrincipal(aURI, attrs);
  prin.forget(aPrincipal);
  return *aPrincipal ? NS_OK : NS_ERROR_FAILURE;
}

NS_IMETHODIMP
nsScriptSecurityManager::CreateCodebasePrincipalFromOrigin(
    const nsACString& aOrigin, nsIPrincipal** aPrincipal) {
  if (StringBeginsWith(aOrigin, NS_LITERAL_CSTRING("["))) {
    return NS_ERROR_INVALID_ARG;
  }

  if (StringBeginsWith(aOrigin,
                       NS_LITERAL_CSTRING(NS_NULLPRINCIPAL_SCHEME ":"))) {
    return NS_ERROR_INVALID_ARG;
  }

  nsCOMPtr<nsIPrincipal> prin = BasePrincipal::CreateCodebasePrincipal(aOrigin);
  prin.forget(aPrincipal);
  return *aPrincipal ? NS_OK : NS_ERROR_FAILURE;
}

NS_IMETHODIMP
nsScriptSecurityManager::CreateNullPrincipal(
    JS::Handle<JS::Value> aOriginAttributes, JSContext* aCx,
    nsIPrincipal** aPrincipal) {
  OriginAttributes attrs;
  if (!aOriginAttributes.isObject() || !attrs.Init(aCx, aOriginAttributes)) {
    return NS_ERROR_INVALID_ARG;
  }
  nsCOMPtr<nsIPrincipal> prin = NullPrincipal::Create(attrs);
  prin.forget(aPrincipal);
  return NS_OK;
}

NS_IMETHODIMP
nsScriptSecurityManager::GetLoadContextCodebasePrincipal(
    nsIURI* aURI, nsILoadContext* aLoadContext, nsIPrincipal** aPrincipal) {
  NS_ENSURE_STATE(aLoadContext);
  OriginAttributes docShellAttrs;
  aLoadContext->GetOriginAttributes(docShellAttrs);

  nsCOMPtr<nsIPrincipal> prin =
      BasePrincipal::CreateCodebasePrincipal(aURI, docShellAttrs);
  prin.forget(aPrincipal);
  return *aPrincipal ? NS_OK : NS_ERROR_FAILURE;
}

NS_IMETHODIMP
nsScriptSecurityManager::GetDocShellCodebasePrincipal(
    nsIURI* aURI, nsIDocShell* aDocShell, nsIPrincipal** aPrincipal) {
  nsCOMPtr<nsIPrincipal> prin = BasePrincipal::CreateCodebasePrincipal(
      aURI, nsDocShell::Cast(aDocShell)->GetOriginAttributes());
  prin.forget(aPrincipal);
  return *aPrincipal ? NS_OK : NS_ERROR_FAILURE;
}

// static
nsIPrincipal* nsScriptSecurityManager::doGetObjectPrincipal(JSObject* aObj) {
  JSCompartment* compartment = js::GetObjectCompartment(aObj);
  JSPrincipals* principals = JS_GetCompartmentPrincipals(compartment);
  return nsJSPrincipals::get(principals);
}

NS_IMETHODIMP
nsScriptSecurityManager::CanCreateWrapper(JSContext* cx, const nsIID& aIID,
                                          nsISupports* aObj,
                                          nsIClassInfo* aClassInfo) {
  // XXX Special case for Exception ?

  uint32_t flags;
  if (aClassInfo && NS_SUCCEEDED(aClassInfo->GetFlags(&flags)) &&
      (flags & nsIClassInfo::DOM_OBJECT)) {
    return NS_OK;
  }

  // We give remote-XUL whitelisted domains a free pass here. See bug 932906.
  JS::Rooted<JS::Realm*> contextRealm(cx, JS::GetCurrentRealmOrNull(cx));
  MOZ_RELEASE_ASSERT(contextRealm);
  if (!xpc::AllowContentXBLScope(contextRealm)) {
    return NS_OK;
  }

  if (nsContentUtils::IsCallerChrome()) {
    return NS_OK;
  }

  // We want to expose nsIDOMXULCommandDispatcher and nsITreeSelection
  // implementations in XBL scopes.
  if (xpc::IsContentXBLScope(contextRealm)) {
    nsCOMPtr<nsIDOMXULCommandDispatcher> dispatcher = do_QueryInterface(aObj);
    if (dispatcher) {
      return NS_OK;
    }

    nsCOMPtr<nsITreeSelection> treeSelection = do_QueryInterface(aObj);
    if (treeSelection) {
      return NS_OK;
    }
  }

  //-- Access denied, report an error
  nsAutoCString originUTF8;
  nsIPrincipal* subjectPrincipal = nsContentUtils::SubjectPrincipal();
  GetPrincipalDomainOrigin(subjectPrincipal, originUTF8);
  NS_ConvertUTF8toUTF16 originUTF16(originUTF8);
  nsAutoCString classInfoNameUTF8;
  if (aClassInfo) {
    aClassInfo->GetClassDescription(classInfoNameUTF8);
  }
  if (classInfoNameUTF8.IsEmpty()) {
    classInfoNameUTF8.AssignLiteral("UnnamedClass");
  }
  NS_ConvertUTF8toUTF16 classInfoUTF16(classInfoNameUTF8);
  nsresult rv;
  nsAutoString errorMsg;
  if (originUTF16.IsEmpty()) {
    const char16_t* formatStrings[] = {classInfoUTF16.get()};
    rv = sStrBundle->FormatStringFromName("CreateWrapperDenied", formatStrings,
                                          1, errorMsg);
  } else {
    const char16_t* formatStrings[] = {classInfoUTF16.get(), originUTF16.get()};
    rv = sStrBundle->FormatStringFromName("CreateWrapperDeniedForOrigin",
                                          formatStrings, 2, errorMsg);
  }
  NS_ENSURE_SUCCESS(rv, rv);

  SetPendingException(cx, errorMsg.get());
  return NS_ERROR_DOM_XPCONNECT_ACCESS_DENIED;
}

NS_IMETHODIMP
nsScriptSecurityManager::CanCreateInstance(JSContext* cx, const nsCID& aCID) {
  if (nsContentUtils::IsCallerChrome()) {
    return NS_OK;
  }

  //-- Access denied, report an error
  nsAutoCString errorMsg("Permission denied to create instance of class. CID=");
  char cidStr[NSID_LENGTH];
  aCID.ToProvidedString(cidStr);
  errorMsg.Append(cidStr);
  SetPendingExceptionASCII(cx, errorMsg.get());
  return NS_ERROR_DOM_XPCONNECT_ACCESS_DENIED;
}

NS_IMETHODIMP
nsScriptSecurityManager::CanGetService(JSContext* cx, const nsCID& aCID) {
  if (nsContentUtils::IsCallerChrome()) {
    return NS_OK;
  }

  //-- Access denied, report an error
  nsAutoCString errorMsg("Permission denied to get service. CID=");
  char cidStr[NSID_LENGTH];
  aCID.ToProvidedString(cidStr);
  errorMsg.Append(cidStr);
  SetPendingExceptionASCII(cx, errorMsg.get());
  return NS_ERROR_DOM_XPCONNECT_ACCESS_DENIED;
}

/////////////////////////////////////
// Method implementing nsIObserver //
/////////////////////////////////////
const char sJSEnabledPrefName[] = "javascript.enabled";
const char sFileOriginPolicyPrefName[] =
    "security.fileuri.strict_origin_policy";

static const char* kObservedPrefs[] = {sJSEnabledPrefName,
                                       sFileOriginPolicyPrefName,
                                       "capability.policy.", nullptr};

NS_IMETHODIMP
nsScriptSecurityManager::Observe(nsISupports* aObject, const char* aTopic,
                                 const char16_t* aMessage) {
  ScriptSecurityPrefChanged();
  return NS_OK;
}

/////////////////////////////////////////////
// Constructor, Destructor, Initialization //
/////////////////////////////////////////////
nsScriptSecurityManager::nsScriptSecurityManager(void)
    : mPrefInitialized(false), mIsJavaScriptEnabled(false) {
  static_assert(
      sizeof(intptr_t) == sizeof(void*),
      "intptr_t and void* have different lengths on this platform. "
      "This may cause a security failure with the SecurityLevel union.");
}

nsresult nsScriptSecurityManager::Init() {
  nsresult rv = CallGetService(NS_IOSERVICE_CONTRACTID, &sIOService);
  NS_ENSURE_SUCCESS(rv, rv);

  InitPrefs();

  nsCOMPtr<nsIStringBundleService> bundleService =
      mozilla::services::GetStringBundleService();
  if (!bundleService) return NS_ERROR_FAILURE;

  rv = bundleService->CreateBundle(
      "chrome://global/locale/security/caps.properties", &sStrBundle);
  NS_ENSURE_SUCCESS(rv, rv);

  // Create our system principal singleton
  RefPtr<SystemPrincipal> system = SystemPrincipal::Create();

  mSystemPrincipal = system;

  //-- Register security check callback in the JS engine
  //   Currently this is used to control access to function.caller
  sContext = danger::GetJSContext();

  static const JSSecurityCallbacks securityCallbacks = {
      ContentSecurityPolicyPermitsJSAction,
      JSPrincipalsSubsume,
  };

  MOZ_ASSERT(!JS_GetSecurityCallbacks(sContext));
  JS_SetSecurityCallbacks(sContext, &securityCallbacks);
  JS_InitDestroyPrincipalsCallback(sContext, nsJSPrincipals::Destroy);

  JS_SetTrustedPrincipals(sContext, system);

  return NS_OK;
}

static StaticRefPtr<nsScriptSecurityManager> gScriptSecMan;

nsScriptSecurityManager::~nsScriptSecurityManager(void) {
  Preferences::RemoveObservers(this, kObservedPrefs);
  if (mDomainPolicy) {
    mDomainPolicy->Deactivate();
  }
  // ContentChild might hold a reference to the domain policy,
  // and it might release it only after the security manager is
  // gone. But we can still assert this for the main process.
  MOZ_ASSERT_IF(XRE_IsParentProcess(), !mDomainPolicy);
}

void nsScriptSecurityManager::Shutdown() {
  if (sContext) {
    JS_SetSecurityCallbacks(sContext, nullptr);
    JS_SetTrustedPrincipals(sContext, nullptr);
    sContext = nullptr;
  }

  NS_IF_RELEASE(sIOService);
  NS_IF_RELEASE(sStrBundle);
}

nsScriptSecurityManager* nsScriptSecurityManager::GetScriptSecurityManager() {
  return gScriptSecMan;
}

/* static */ void nsScriptSecurityManager::InitStatics() {
  RefPtr<nsScriptSecurityManager> ssManager = new nsScriptSecurityManager();
  nsresult rv = ssManager->Init();
  if (NS_FAILED(rv)) {
    MOZ_CRASH("ssManager->Init() failed");
  }

  ClearOnShutdown(&gScriptSecMan);
  gScriptSecMan = ssManager;
}

// Currently this nsGenericFactory constructor is used only from FastLoad
// (XPCOM object deserialization) code, when "creating" the system principal
// singleton.
already_AddRefed<SystemPrincipal>
nsScriptSecurityManager::SystemPrincipalSingletonConstructor() {
  if (gScriptSecMan)
    return do_AddRef(gScriptSecMan->mSystemPrincipal)
        .downcast<SystemPrincipal>();
  return nullptr;
}

struct IsWhitespace {
  static bool Test(char aChar) { return NS_IsAsciiWhitespace(aChar); };
};
struct IsWhitespaceOrComma {
  static bool Test(char aChar) {
    return aChar == ',' || NS_IsAsciiWhitespace(aChar);
  };
};

template <typename Predicate>
uint32_t SkipPast(const nsCString& str, uint32_t base) {
  while (base < str.Length() && Predicate::Test(str[base])) {
    ++base;
  }
  return base;
}

template <typename Predicate>
uint32_t SkipUntil(const nsCString& str, uint32_t base) {
  while (base < str.Length() && !Predicate::Test(str[base])) {
    ++base;
  }
  return base;
}

inline void nsScriptSecurityManager::ScriptSecurityPrefChanged() {
  MOZ_ASSERT(mPrefInitialized);
  mIsJavaScriptEnabled =
      Preferences::GetBool(sJSEnabledPrefName, mIsJavaScriptEnabled);
  sStrictFileOriginPolicy =
      Preferences::GetBool(sFileOriginPolicyPrefName, false);
  mFileURIWhitelist.reset();
}

void nsScriptSecurityManager::AddSitesToFileURIWhitelist(
    const nsCString& aSiteList) {
  for (uint32_t base = SkipPast<IsWhitespace>(aSiteList, 0), bound = 0;
       base < aSiteList.Length();
       base = SkipPast<IsWhitespace>(aSiteList, bound)) {
    // Grab the current site.
    bound = SkipUntil<IsWhitespace>(aSiteList, base);
    nsAutoCString site(Substring(aSiteList, base, bound - base));

    // Check if the URI is schemeless. If so, add both http and https.
    nsAutoCString unused;
    if (NS_FAILED(sIOService->ExtractScheme(site, unused))) {
      AddSitesToFileURIWhitelist(NS_LITERAL_CSTRING("http://") + site);
      AddSitesToFileURIWhitelist(NS_LITERAL_CSTRING("https://") + site);
      continue;
    }

    // Convert it to a URI and add it to our list.
    nsCOMPtr<nsIURI> uri;
    nsresult rv =
        NS_NewURI(getter_AddRefs(uri), site, nullptr, nullptr, sIOService);
    if (NS_SUCCEEDED(rv)) {
      mFileURIWhitelist.ref().AppendElement(uri);
    } else {
      nsCOMPtr<nsIConsoleService> console(
          do_GetService("@mozilla.org/consoleservice;1"));
      if (console) {
        nsAutoString msg =
            NS_LITERAL_STRING(
                "Unable to to add site to file:// URI whitelist: ") +
            NS_ConvertASCIItoUTF16(site);
        console->LogStringMessage(msg.get());
      }
    }
  }
}

nsresult nsScriptSecurityManager::InitPrefs() {
  nsIPrefBranch* branch = Preferences::GetRootBranch();
  NS_ENSURE_TRUE(branch, NS_ERROR_FAILURE);

  mPrefInitialized = true;

  // Set the initial value of the "javascript.enabled" prefs
  ScriptSecurityPrefChanged();

  // set observer callbacks in case the value of the prefs change
  Preferences::AddStrongObservers(this, kObservedPrefs);

  OriginAttributes::InitPrefs();

  return NS_OK;
}

NS_IMETHODIMP
nsScriptSecurityManager::GetDomainPolicyActive(bool* aRv) {
  *aRv = !!mDomainPolicy;
  return NS_OK;
}

NS_IMETHODIMP
nsScriptSecurityManager::ActivateDomainPolicy(nsIDomainPolicy** aRv) {
  if (!XRE_IsParentProcess()) {
    return NS_ERROR_SERVICE_NOT_AVAILABLE;
  }

  return ActivateDomainPolicyInternal(aRv);
}

NS_IMETHODIMP
nsScriptSecurityManager::ActivateDomainPolicyInternal(nsIDomainPolicy** aRv) {
  // We only allow one domain policy at a time. The holder of the previous
  // policy must explicitly deactivate it first.
  if (mDomainPolicy) {
    return NS_ERROR_SERVICE_NOT_AVAILABLE;
  }

  mDomainPolicy = new DomainPolicy();
  nsCOMPtr<nsIDomainPolicy> ptr = mDomainPolicy;
  ptr.forget(aRv);
  return NS_OK;
}

// Intentionally non-scriptable. Script must have a reference to the
// nsIDomainPolicy to deactivate it.
void nsScriptSecurityManager::DeactivateDomainPolicy() {
  mDomainPolicy = nullptr;
}

void nsScriptSecurityManager::CloneDomainPolicy(DomainPolicyClone* aClone) {
  MOZ_ASSERT(aClone);
  if (mDomainPolicy) {
    mDomainPolicy->CloneDomainPolicy(aClone);
  } else {
    aClone->active() = false;
  }
}

NS_IMETHODIMP
nsScriptSecurityManager::PolicyAllowsScript(nsIURI* aURI, bool* aRv) {
  nsresult rv;

  // Compute our rule. If we don't have any domain policy set up that might
  // provide exceptions to this rule, we're done.
  *aRv = mIsJavaScriptEnabled;
  if (!mDomainPolicy) {
    return NS_OK;
  }

  // We have a domain policy. Grab the appropriate set of exceptions to the
  // rule (either the blacklist or the whitelist, depending on whether script
  // is enabled or disabled by default).
  nsCOMPtr<nsIDomainSet> exceptions;
  nsCOMPtr<nsIDomainSet> superExceptions;
  if (*aRv) {
    mDomainPolicy->GetBlacklist(getter_AddRefs(exceptions));
    mDomainPolicy->GetSuperBlacklist(getter_AddRefs(superExceptions));
  } else {
    mDomainPolicy->GetWhitelist(getter_AddRefs(exceptions));
    mDomainPolicy->GetSuperWhitelist(getter_AddRefs(superExceptions));
  }

  bool contains;
  rv = exceptions->Contains(aURI, &contains);
  NS_ENSURE_SUCCESS(rv, rv);
  if (contains) {
    *aRv = !*aRv;
    return NS_OK;
  }
  rv = superExceptions->ContainsSuperDomain(aURI, &contains);
  NS_ENSURE_SUCCESS(rv, rv);
  if (contains) {
    *aRv = !*aRv;
  }

  return NS_OK;
}

const nsTArray<nsCOMPtr<nsIURI>>&
nsScriptSecurityManager::EnsureFileURIWhitelist() {
  if (mFileURIWhitelist.isSome()) {
    return mFileURIWhitelist.ref();
  }

  //
  // Rebuild the set of principals for which we allow file:// URI loads. This
  // implements a small subset of an old pref-based CAPS people that people
  // have come to depend on. See bug 995943.
  //

  mFileURIWhitelist.emplace();
  nsAutoCString policies;
  mozilla::Preferences::GetCString("capability.policy.policynames", policies);
  for (uint32_t base = SkipPast<IsWhitespaceOrComma>(policies, 0), bound = 0;
       base < policies.Length();
       base = SkipPast<IsWhitespaceOrComma>(policies, bound)) {
    // Grab the current policy name.
    bound = SkipUntil<IsWhitespaceOrComma>(policies, base);
    auto policyName = Substring(policies, base, bound - base);

    // Figure out if this policy allows loading file:// URIs. If not, we can
    // skip it.
    nsCString checkLoadURIPrefName =
        NS_LITERAL_CSTRING("capability.policy.") + policyName +
        NS_LITERAL_CSTRING(".checkloaduri.enabled");
    nsAutoString value;
    nsresult rv = Preferences::GetString(checkLoadURIPrefName.get(), value);
    if (NS_FAILED(rv) || !value.LowerCaseEqualsLiteral("allaccess")) {
      continue;
    }

    // Grab the list of domains associated with this policy.
    nsCString domainPrefName = NS_LITERAL_CSTRING("capability.policy.") +
                               policyName + NS_LITERAL_CSTRING(".sites");
    nsAutoCString siteList;
    Preferences::GetCString(domainPrefName.get(), siteList);
    AddSitesToFileURIWhitelist(siteList);
  }

  return mFileURIWhitelist.ref();
}