caps/nsScriptSecurityManager.cpp
author Kris Maglione <maglione.k@gmail.com>
Thu, 02 Nov 2017 19:56:27 -0700
changeset 390018 4350a326a49805c6138aabd0ed68136498bf97cd
parent 388469 df948a52ffb1e48a8fc7e43867557710b37f6914
child 394526 ec15d17d85cb9423cd45fa19069d831c4c563d8c
permissions -rw-r--r--
Bug 1412345: Downgrade expanded principals before inheriting. r=bz,krizsa There are several ways that expanded principals can be used as triggering principals for requests. While that works fine for security checks, it also sometimes causes them to be inherited, and used as result principals in contexts where expanded principals aren't allowed. This patch changes our inheritance behavior so that expanded principals are downgraded to the most appropriate constituent principal when they would otherwise be inherited. The logic for choosing the most appropriate principal is a bit suspect, and may eventually need to be changed to always select the last whitelist principal, but I chose it to preserve the current principal downgrade behavior used by XMLHttpRequest for the time being. MozReview-Commit-ID: 9fvAKr2e2fa

/* -*- 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 "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)
{
    // Make a clone of the incoming URI, because we're going to mutate it.
    nsCOMPtr<nsIURI> probe;
    nsresult rv = aProbeArg->Clone(getter_AddRefs(probe));
    NS_ENSURE_SUCCESS(rv, false);

    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 = probe->SetHost(newHost);
        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;
    }

    // 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(aTargetBaseURI,
                             nsIProtocolHandler::URI_IS_UI_RESOURCE,
                             &hasFlags);
    NS_ENSURE_SUCCESS(rv, rv);
    if (hasFlags) {
        if (aFlags & nsIScriptSecurityManager::ALLOW_CHROME) {
            // For now, don't change behavior for moz-icon:// and just allow it.
            if (!targetScheme.EqualsLiteral("chrome")
                    && !targetScheme.EqualsLiteral("resource")) {
                return NS_OK;
            }

            // 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 {
                // 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 nsIXPCException ?

    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();
}