gecko-dev/caps/nsPrincipal.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 sw=2 et 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 "nsPrincipal.h"

#include "mozIThirdPartyUtil.h"
#include "nscore.h"
#include "nsScriptSecurityManager.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "pratom.h"
#include "nsIURI.h"
#include "nsIURL.h"
#include "nsIStandardURL.h"
#include "nsIURIWithPrincipal.h"
#include "nsJSPrincipals.h"
#include "nsIEffectiveTLDService.h"
#include "nsIClassInfoImpl.h"
#include "nsIProtocolHandler.h"
#include "nsError.h"
#include "nsIContentSecurityPolicy.h"
#include "nsNetCID.h"
#include "jswrapper.h"

#include "mozilla/dom/ScriptSettings.h"
#include "mozilla/Preferences.h"
#include "mozilla/HashFunctions.h"

#include "nsIAppsService.h"
#include "mozIApplication.h"

using namespace mozilla;

static bool gIsWhitelistingTestDomains = false;
static bool gCodeBasePrincipalSupport = false;

static bool URIIsImmutable(nsIURI* aURI)
{
  nsCOMPtr<nsIMutable> mutableObj(do_QueryInterface(aURI));
  bool isMutable;
  return
    mutableObj &&
    NS_SUCCEEDED(mutableObj->GetMutable(&isMutable)) &&
    !isMutable;
}

NS_IMPL_CLASSINFO(nsPrincipal, nullptr, nsIClassInfo::MAIN_THREAD_ONLY,
                  NS_PRINCIPAL_CID)
NS_IMPL_QUERY_INTERFACE_CI(nsPrincipal,
                           nsIPrincipal,
                           nsISerializable)
NS_IMPL_CI_INTERFACE_GETTER(nsPrincipal,
                            nsIPrincipal,
                            nsISerializable)

// Called at startup:
/* static */ void
nsPrincipal::InitializeStatics()
{
  Preferences::AddBoolVarCache(
    &gIsWhitelistingTestDomains,
    "layout.css.unprefixing-service.include-test-domains");

  Preferences::AddBoolVarCache(&gCodeBasePrincipalSupport,
                               "signed.applets.codebase_principal_support",
                               false);
}

nsPrincipal::nsPrincipal()
  : mCodebaseImmutable(false)
  , mDomainImmutable(false)
  , mInitialized(false)
{ }

nsPrincipal::~nsPrincipal()
{ }

nsresult
nsPrincipal::Init(nsIURI *aCodebase, const OriginAttributes& aOriginAttributes)
{
  NS_ENSURE_STATE(!mInitialized);
  NS_ENSURE_ARG(aCodebase);

  mInitialized = true;

  mCodebase = NS_TryToMakeImmutable(aCodebase);
  mCodebaseImmutable = URIIsImmutable(mCodebase);
  mOriginAttributes = aOriginAttributes;

  return NS_OK;
}

void
nsPrincipal::GetScriptLocation(nsACString &aStr)
{
  mCodebase->GetSpec(aStr);
}

/* static */ nsresult
nsPrincipal::GetOriginForURI(nsIURI* aURI, nsACString& aOrigin)
{
  if (!aURI) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIURI> origin = NS_GetInnermostURI(aURI);
  if (!origin) {
    return NS_ERROR_FAILURE;
  }

  nsAutoCString hostPort;

  // chrome: URLs don't have a meaningful origin, so make
  // sure we just get the full spec for them.
  // XXX this should be removed in favor of the solution in
  // bug 160042.
  bool isChrome;
  nsresult rv = origin->SchemeIs("chrome", &isChrome);
  if (NS_SUCCEEDED(rv) && !isChrome) {
    rv = origin->GetAsciiHostPort(hostPort);
    // Some implementations return an empty string, treat it as no support
    // for asciiHost by that implementation.
    if (hostPort.IsEmpty()) {
      rv = NS_ERROR_FAILURE;
    }
  }

  // We want the invariant that prinA.origin == prinB.origin i.f.f.
  // prinA.equals(prinB). However, this requires that we impose certain constraints
  // on the behavior and origin semantics of principals, and in particular, forbid
  // creating origin strings for principals whose equality constraints are not
  // expressible as strings (i.e. object equality). Moreover, we want to forbid URIs
  // containing the magic "^" we use as a separating character for origin
  // attributes.
  //
  // These constraints can generally be achieved by restricting .origin to
  // nsIStandardURL-based URIs, but there are a few other URI schemes that we need
  // to handle.
  bool isBehaved;
  if ((NS_SUCCEEDED(origin->SchemeIs("about", &isBehaved)) && isBehaved) ||
      (NS_SUCCEEDED(origin->SchemeIs("moz-safe-about", &isBehaved)) && isBehaved) ||
      (NS_SUCCEEDED(origin->SchemeIs("indexeddb", &isBehaved)) && isBehaved)) {
    rv = origin->GetAsciiSpec(aOrigin);
    NS_ENSURE_SUCCESS(rv, rv);
    // These URIs could technically contain a '^', but they never should.
    if (NS_WARN_IF(aOrigin.FindChar('^', 0) != -1)) {
      aOrigin.Truncate();
      return NS_ERROR_FAILURE;
    }
    return NS_OK;
  }

  if (NS_SUCCEEDED(rv) && !isChrome) {
    rv = origin->GetScheme(aOrigin);
    NS_ENSURE_SUCCESS(rv, rv);
    aOrigin.AppendLiteral("://");
    aOrigin.Append(hostPort);
  }
  else {
    // If we reached this branch, we can only create an origin if we have a nsIStandardURL.
    // So, we query to a nsIStandardURL, and fail if we aren't an instance of an nsIStandardURL
    // nsIStandardURLs have the good property of escaping the '^' character in their specs,
    // which means that we can be sure that the caret character (which is reserved for delimiting
    // the end of the spec, and the beginning of the origin attributes) is not present in the
    // origin string
    nsCOMPtr<nsIStandardURL> standardURL = do_QueryInterface(origin);
    NS_ENSURE_TRUE(standardURL, NS_ERROR_FAILURE);
    rv = origin->GetAsciiSpec(aOrigin);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}

nsresult
nsPrincipal::GetOriginInternal(nsACString& aOrigin)
{
  return GetOriginForURI(mCodebase, aOrigin);
}

bool
nsPrincipal::SubsumesInternal(nsIPrincipal* aOther,
                              BasePrincipal::DocumentDomainConsideration aConsideration)
{
  MOZ_ASSERT(aOther);

  // For nsPrincipal, Subsumes is equivalent to Equals.
  if (aOther == this) {
    return true;
  }

  if (OriginAttributesRef() != Cast(aOther)->OriginAttributesRef()) {
    return false;
  }

  // If either the subject or the object has changed its principal by
  // explicitly setting document.domain then the other must also have
  // done so in order to be considered the same origin. This prevents
  // DNS spoofing based on document.domain (154930)
  nsresult rv;
  if (aConsideration == ConsiderDocumentDomain) {
    // Get .domain on each principal.
    nsCOMPtr<nsIURI> thisDomain, otherDomain;
    GetDomain(getter_AddRefs(thisDomain));
    aOther->GetDomain(getter_AddRefs(otherDomain));

    // If either has .domain set, we have equality i.f.f. the domains match.
    // Otherwise, we fall through to the non-document-domain-considering case.
    if (thisDomain || otherDomain) {
      return nsScriptSecurityManager::SecurityCompareURIs(thisDomain, otherDomain);
    }
  }

    nsCOMPtr<nsIURI> otherURI;
    rv = aOther->GetURI(getter_AddRefs(otherURI));
    NS_ENSURE_SUCCESS(rv, false);

  // Compare codebases.
  return nsScriptSecurityManager::SecurityCompareURIs(mCodebase, otherURI);
}

NS_IMETHODIMP
nsPrincipal::GetURI(nsIURI** aURI)
{
  if (mCodebaseImmutable) {
    NS_ADDREF(*aURI = mCodebase);
    return NS_OK;
  }

  if (!mCodebase) {
    *aURI = nullptr;
    return NS_OK;
  }

  return NS_EnsureSafeToReturn(mCodebase, aURI);
}

NS_IMETHODIMP
nsPrincipal::CheckMayLoad(nsIURI* aURI, bool aReport, bool aAllowIfInheritsPrincipal)
{
   if (aAllowIfInheritsPrincipal) {
    // If the caller specified to allow loads of URIs that inherit
    // our principal, allow the load if this URI inherits its principal
    if (nsPrincipal::IsPrincipalInherited(aURI)) {
      return NS_OK;
    }
  }

  // See if aURI is something like a Blob URI that is actually associated with
  // a principal.
  nsCOMPtr<nsIURIWithPrincipal> uriWithPrin = do_QueryInterface(aURI);
  nsCOMPtr<nsIPrincipal> uriPrin;
  if (uriWithPrin) {
    uriWithPrin->GetPrincipal(getter_AddRefs(uriPrin));
  }
  if (uriPrin && nsIPrincipal::Subsumes(uriPrin)) {
      return NS_OK;
  }

  // If this principal is associated with an addon, check whether that addon
  // has been given permission to load from this domain.
  if (AddonAllowsLoad(aURI)) {
    return NS_OK;
  }

  if (nsScriptSecurityManager::SecurityCompareURIs(mCodebase, aURI)) {
    return NS_OK;
  }

  // If strict file origin policy is in effect, local files will always fail
  // SecurityCompareURIs unless they are identical. Explicitly check file origin
  // policy, in that case.
  if (nsScriptSecurityManager::GetStrictFileOriginPolicy() &&
      NS_URIIsLocalFile(aURI) &&
      NS_RelaxStrictFileOriginPolicy(aURI, mCodebase)) {
    return NS_OK;
  }

  if (aReport) {
    nsScriptSecurityManager::ReportError(nullptr, NS_LITERAL_STRING("CheckSameOriginError"), mCodebase, aURI);
  }
  return NS_ERROR_DOM_BAD_URI;
}

void
nsPrincipal::SetURI(nsIURI* aURI)
{
  mCodebase = NS_TryToMakeImmutable(aURI);
  mCodebaseImmutable = URIIsImmutable(mCodebase);
}

NS_IMETHODIMP
nsPrincipal::GetHashValue(uint32_t* aValue)
{
  NS_PRECONDITION(mCodebase, "Need a codebase");

  *aValue = nsScriptSecurityManager::HashPrincipalByOrigin(this);
  return NS_OK;
}

NS_IMETHODIMP
nsPrincipal::GetDomain(nsIURI** aDomain)
{
  if (!mDomain) {
    *aDomain = nullptr;
    return NS_OK;
  }

  if (mDomainImmutable) {
    NS_ADDREF(*aDomain = mDomain);
    return NS_OK;
  }

  return NS_EnsureSafeToReturn(mDomain, aDomain);
}

NS_IMETHODIMP
nsPrincipal::SetDomain(nsIURI* aDomain)
{
  mDomain = NS_TryToMakeImmutable(aDomain);
  mDomainImmutable = URIIsImmutable(mDomain);

  // Recompute all wrappers between compartments using this principal and other
  // non-chrome compartments.
  AutoSafeJSContext cx;
  JSPrincipals *principals = nsJSPrincipals::get(static_cast<nsIPrincipal*>(this));
  bool success = js::RecomputeWrappers(cx, js::ContentCompartmentsOnly(),
                                       js::CompartmentsWithPrincipals(principals));
  NS_ENSURE_TRUE(success, NS_ERROR_FAILURE);
  success = js::RecomputeWrappers(cx, js::CompartmentsWithPrincipals(principals),
                                  js::ContentCompartmentsOnly());
  NS_ENSURE_TRUE(success, NS_ERROR_FAILURE);

  return NS_OK;
}

NS_IMETHODIMP
nsPrincipal::GetBaseDomain(nsACString& aBaseDomain)
{
  // For a file URI, we return the file path.
  if (NS_URIIsLocalFile(mCodebase)) {
    nsCOMPtr<nsIURL> url = do_QueryInterface(mCodebase);

    if (url) {
      return url->GetFilePath(aBaseDomain);
    }
  }

  bool hasNoRelativeFlag;
  nsresult rv = NS_URIChainHasFlags(mCodebase,
                                    nsIProtocolHandler::URI_NORELATIVE,
                                    &hasNoRelativeFlag);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (hasNoRelativeFlag) {
    return mCodebase->GetSpec(aBaseDomain);
  }

  // For everything else, we ask the TLD service via
  // the ThirdPartyUtil.
  nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
    do_GetService(THIRDPARTYUTIL_CONTRACTID);
  if (thirdPartyUtil) {
    return thirdPartyUtil->GetBaseDomain(mCodebase, aBaseDomain);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsPrincipal::Read(nsIObjectInputStream* aStream)
{
  nsCOMPtr<nsISupports> supports;
  nsCOMPtr<nsIURI> codebase;
  nsresult rv = NS_ReadOptionalObject(aStream, true, getter_AddRefs(supports));
  if (NS_FAILED(rv)) {
    return rv;
  }

  codebase = do_QueryInterface(supports);

  nsCOMPtr<nsIURI> domain;
  rv = NS_ReadOptionalObject(aStream, true, getter_AddRefs(supports));
  if (NS_FAILED(rv)) {
    return rv;
  }

  domain = do_QueryInterface(supports);

  nsAutoCString suffix;
  rv = aStream->ReadCString(suffix);
  NS_ENSURE_SUCCESS(rv, rv);

  OriginAttributes attrs;
  bool ok = attrs.PopulateFromSuffix(suffix);
  NS_ENSURE_TRUE(ok, NS_ERROR_FAILURE);

  rv = NS_ReadOptionalObject(aStream, true, getter_AddRefs(supports));
  NS_ENSURE_SUCCESS(rv, rv);

  // This may be null.
  nsCOMPtr<nsIContentSecurityPolicy> csp = do_QueryInterface(supports, &rv);

  rv = Init(codebase, attrs);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = SetCsp(csp);
  NS_ENSURE_SUCCESS(rv, rv);

  // need to link in the CSP context here (link in the URI of the protected
  // resource).
  if (csp) {
    csp->SetRequestContext(codebase, nullptr, nullptr);
  }

  SetDomain(domain);

  return NS_OK;
}

NS_IMETHODIMP
nsPrincipal::Write(nsIObjectOutputStream* aStream)
{
  NS_ENSURE_STATE(mCodebase);
  nsresult rv = NS_WriteOptionalCompoundObject(aStream, mCodebase, NS_GET_IID(nsIURI),
                                               true);
  if (NS_FAILED(rv)) {
    return rv;
  }

  rv = NS_WriteOptionalCompoundObject(aStream, mDomain, NS_GET_IID(nsIURI),
                                      true);
  if (NS_FAILED(rv)) {
    return rv;
  }

  nsAutoCString suffix;
  OriginAttributesRef().CreateSuffix(suffix);

  rv = aStream->WriteStringZ(suffix.get());
  NS_ENSURE_SUCCESS(rv, rv);

  rv = NS_WriteOptionalCompoundObject(aStream, mCSP,
                                      NS_GET_IID(nsIContentSecurityPolicy),
                                      true);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // mCodebaseImmutable and mDomainImmutable will be recomputed based
  // on the deserialized URIs in Read().

  return NS_OK;
}

// Helper-function to indicate whether the CSS Unprefixing Service
// whitelist should include dummy domains that are only intended for
// use in testing. (Controlled by a pref.)
static inline bool
IsWhitelistingTestDomains()
{
  return gIsWhitelistingTestDomains;
}

// Checks if the given URI's host is on our "full domain" whitelist
// (i.e. if it's an exact match against a domain that needs unprefixing)
static bool
IsOnFullDomainWhitelist(nsIURI* aURI)
{
  nsAutoCString hostStr;
  nsresult rv = aURI->GetHost(hostStr);
  NS_ENSURE_SUCCESS(rv, false);

  // NOTE: This static whitelist is expected to be short. If that changes,
  // we should consider a different representation; e.g. hash-set, prefix tree.
  static const nsLiteralCString sFullDomainsOnWhitelist[] = {
    // 0th entry only active when testing:
    NS_LITERAL_CSTRING("test1.example.org"),
    NS_LITERAL_CSTRING("map.baidu.com"),
    NS_LITERAL_CSTRING("3g.163.com"),
    NS_LITERAL_CSTRING("3glogo.gtimg.com"), // for 3g.163.com
    NS_LITERAL_CSTRING("info.3g.qq.com"), // for 3g.qq.com
    NS_LITERAL_CSTRING("3gimg.qq.com"), // for 3g.qq.com
    NS_LITERAL_CSTRING("img.m.baidu.com"), // for [shucheng|ks].baidu.com
    NS_LITERAL_CSTRING("m.mogujie.com"),
    NS_LITERAL_CSTRING("touch.qunar.com"),
    NS_LITERAL_CSTRING("mjs.sinaimg.cn"), // for sina.cn
    NS_LITERAL_CSTRING("static.qiyi.com"), // for m.iqiyi.com
    NS_LITERAL_CSTRING("cdn.kuaidi100.com"), // for m.kuaidi100.com
    NS_LITERAL_CSTRING("m.pc6.com"),
    NS_LITERAL_CSTRING("m.haosou.com"),
    NS_LITERAL_CSTRING("m.mi.com"),
    NS_LITERAL_CSTRING("wappass.baidu.com"),
    NS_LITERAL_CSTRING("m.video.baidu.com"),
    NS_LITERAL_CSTRING("m.video.baidu.com"),
    NS_LITERAL_CSTRING("imgcache.gtimg.cn"), // for m.v.qq.com
    NS_LITERAL_CSTRING("s.tabelog.jp"),
    NS_LITERAL_CSTRING("s.yimg.jp"), // for s.tabelog.jp
    NS_LITERAL_CSTRING("i.yimg.jp"), // for *.yahoo.co.jp
    NS_LITERAL_CSTRING("ai.yimg.jp"), // for *.yahoo.co.jp
    NS_LITERAL_CSTRING("m.finance.yahoo.co.jp"),
    NS_LITERAL_CSTRING("daily.c.yimg.jp"), // for sp.daily.co.jp
    NS_LITERAL_CSTRING("stat100.ameba.jp"), // for ameblo.jp
    NS_LITERAL_CSTRING("user.ameba.jp"), // for ameblo.jp
    NS_LITERAL_CSTRING("www.goo.ne.jp"),
    NS_LITERAL_CSTRING("x.gnst.jp"), // for mobile.gnavi.co.jp
    NS_LITERAL_CSTRING("c.x.gnst.jp"), // for mobile.gnavi.co.jp
    NS_LITERAL_CSTRING("www.smbc-card.com"),
    NS_LITERAL_CSTRING("static.card.jp.rakuten-static.com"), // for rakuten-card.co.jp
    NS_LITERAL_CSTRING("img.travel.rakuten.co.jp"), // for travel.rakuten.co.jp
    NS_LITERAL_CSTRING("img.mixi.net"), // for mixi.jp
    NS_LITERAL_CSTRING("girlschannel.net"),
    NS_LITERAL_CSTRING("www.fancl.co.jp"),
    NS_LITERAL_CSTRING("s.cosme.net"),
    NS_LITERAL_CSTRING("www.sapporobeer.jp"),
    NS_LITERAL_CSTRING("www.mapion.co.jp"),
    NS_LITERAL_CSTRING("touch.navitime.co.jp"),
    NS_LITERAL_CSTRING("sp.mbga.jp"),
    NS_LITERAL_CSTRING("ava-a.sp.mbga.jp"), // for sp.mbga.jp
    NS_LITERAL_CSTRING("www.ntv.co.jp"),
    NS_LITERAL_CSTRING("mobile.suntory.co.jp"), // for suntory.jp
    NS_LITERAL_CSTRING("www.aeonsquare.net"),
    NS_LITERAL_CSTRING("mw.nikkei.com"),
    NS_LITERAL_CSTRING("www.nhk.or.jp"),
    NS_LITERAL_CSTRING("www.tokyo-sports.co.jp"),
    NS_LITERAL_CSTRING("www.bellemaison.jp"),
    NS_LITERAL_CSTRING("www.kuronekoyamato.co.jp"),
    NS_LITERAL_CSTRING("formassist.jp"), // for orico.jp
    NS_LITERAL_CSTRING("sp.m.reuters.co.jp"),
    NS_LITERAL_CSTRING("www.atre.co.jp"),
    NS_LITERAL_CSTRING("www.jtb.co.jp"),
    NS_LITERAL_CSTRING("www.sharp.co.jp"),
    NS_LITERAL_CSTRING("www.biccamera.com"),
    NS_LITERAL_CSTRING("weathernews.jp"),
    NS_LITERAL_CSTRING("cache.ymail.jp"), // for www.yamada-denkiweb.com
  };
  static const size_t sNumFullDomainsOnWhitelist =
    MOZ_ARRAY_LENGTH(sFullDomainsOnWhitelist);

  // Skip 0th (dummy) entry in whitelist, unless a pref is enabled.
  const size_t firstWhitelistIdx = IsWhitelistingTestDomains() ? 0 : 1;

  for (size_t i = firstWhitelistIdx; i < sNumFullDomainsOnWhitelist; ++i) {
    if (hostStr == sFullDomainsOnWhitelist[i]) {
      return true;
    }
  }
  return false;
}

// Checks if the given URI's host is on our "base domain" whitelist
// (i.e. if it's a subdomain of some host that we've whitelisted as needing
// unprefixing for all its subdomains)
static bool
IsOnBaseDomainWhitelist(nsIURI* aURI)
{
  static const nsLiteralCString sBaseDomainsOnWhitelist[] = {
    // 0th entry only active when testing:
    NS_LITERAL_CSTRING("test2.example.org"),
    NS_LITERAL_CSTRING("tbcdn.cn"), // for m.taobao.com
    NS_LITERAL_CSTRING("alicdn.com"), // for m.taobao.com
    NS_LITERAL_CSTRING("dpfile.com"), // for m.dianping.com
    NS_LITERAL_CSTRING("hao123img.com"), // for hao123.com
    NS_LITERAL_CSTRING("tabelog.k-img.com"), // for s.tabelog.com
    NS_LITERAL_CSTRING("tsite.jp"), // for *.tsite.jp
  };
  static const size_t sNumBaseDomainsOnWhitelist =
    MOZ_ARRAY_LENGTH(sBaseDomainsOnWhitelist);

  nsCOMPtr<nsIEffectiveTLDService> tldService =
    do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID);

  if (tldService) {
    // Skip 0th test-entry in whitelist, unless the testing pref is enabled.
    const size_t firstWhitelistIdx = IsWhitelistingTestDomains() ? 0 : 1;

    // Right now, the test base-domain "test2.example.org" is the only entry in
    // its whitelist with a nonzero "depth". So we'll only bother going beyond
    // 0 depth (to 1) if that entry is enabled. (No point in slowing down the
    // normal codepath, for the benefit of a disabled test domain.)  If we add a
    // "real" base-domain with a depth of >= 1 to our whitelist, we can get rid
    // of this conditional & just make this a static variable.
    const uint32_t maxSubdomainDepth = IsWhitelistingTestDomains() ? 1 : 0;

    for (uint32_t subdomainDepth = 0;
         subdomainDepth <= maxSubdomainDepth; ++subdomainDepth) {

      // Get the base domain (to depth |subdomainDepth|) from passed-in URI:
      nsAutoCString baseDomainStr;
      nsresult rv = tldService->GetBaseDomain(aURI, subdomainDepth,
                                              baseDomainStr);
      if (NS_FAILED(rv)) {
        // aURI doesn't have |subdomainDepth| levels of subdomains. If we got
        // here without a match yet, then aURI is not on our whitelist.
        return false;
      }

      // Compare the base domain against each entry in our whitelist:
      for (size_t i = firstWhitelistIdx; i < sNumBaseDomainsOnWhitelist; ++i) {
        if (baseDomainStr == sBaseDomainsOnWhitelist[i]) {
          return true;
        }
      }
    }
  }

  return false;
}

// The actual (non-cached) implementation of IsOnCSSUnprefixingWhitelist():
static bool
IsOnCSSUnprefixingWhitelistImpl(nsIURI* aURI)
{
  // Check scheme, so we can drop any non-HTTP/HTTPS URIs right away
  nsAutoCString schemeStr;
  nsresult rv = aURI->GetScheme(schemeStr);
  NS_ENSURE_SUCCESS(rv, false);

  // Only proceed if scheme is "http" or "https"
  if (!(StringBeginsWith(schemeStr, NS_LITERAL_CSTRING("http")) &&
        (schemeStr.Length() == 4 ||
         (schemeStr.Length() == 5 && schemeStr[4] == 's')))) {
    return false;
  }

  return (IsOnFullDomainWhitelist(aURI) ||
          IsOnBaseDomainWhitelist(aURI));
}


bool
nsPrincipal::IsOnCSSUnprefixingWhitelist()
{
  if (mIsOnCSSUnprefixingWhitelist.isNothing()) {
    // Value not cached -- perform our lazy whitelist-check.
    // (NOTE: If our URI is mutable, we just assume it's not on the whitelist,
    // since our caching strategy won't work. This isn't expected to be common.)
    mIsOnCSSUnprefixingWhitelist.emplace(
      mCodebaseImmutable &&
      IsOnCSSUnprefixingWhitelistImpl(mCodebase));
  }

  return *mIsOnCSSUnprefixingWhitelist;
}

/************************************************************************************************************************/

NS_IMPL_CLASSINFO(nsExpandedPrincipal, nullptr, nsIClassInfo::MAIN_THREAD_ONLY,
                  NS_EXPANDEDPRINCIPAL_CID)
NS_IMPL_QUERY_INTERFACE_CI(nsExpandedPrincipal,
                           nsIPrincipal,
                           nsIExpandedPrincipal)
NS_IMPL_CI_INTERFACE_GETTER(nsExpandedPrincipal,
                             nsIPrincipal,
                             nsIExpandedPrincipal)

struct OriginComparator
{
  bool LessThan(nsIPrincipal* a, nsIPrincipal* b) const
  {
    nsAutoCString originA;
    nsresult rv = a->GetOrigin(originA);
    NS_ENSURE_SUCCESS(rv, false);
    nsAutoCString originB;
    rv = b->GetOrigin(originB);
    NS_ENSURE_SUCCESS(rv, false);
    return originA < originB;
  }

  bool Equals(nsIPrincipal* a, nsIPrincipal* b) const
  {
    nsAutoCString originA;
    nsresult rv = a->GetOrigin(originA);
    NS_ENSURE_SUCCESS(rv, false);
    nsAutoCString originB;
    rv = b->GetOrigin(originB);
    NS_ENSURE_SUCCESS(rv, false);
    return a == b;
  }
};

nsExpandedPrincipal::nsExpandedPrincipal(nsTArray<nsCOMPtr <nsIPrincipal> > &aWhiteList)
{
  // We force the principals to be sorted by origin so that nsExpandedPrincipal
  // origins can have a canonical form.
  OriginComparator c;
  for (size_t i = 0; i < aWhiteList.Length(); ++i) {
    mPrincipals.InsertElementSorted(aWhiteList[i], c);
  }
}

nsExpandedPrincipal::~nsExpandedPrincipal()
{ }

NS_IMETHODIMP
nsExpandedPrincipal::GetDomain(nsIURI** aDomain)
{
  *aDomain = nullptr;
  return NS_OK;
}

NS_IMETHODIMP
nsExpandedPrincipal::SetDomain(nsIURI* aDomain)
{
  return NS_OK;
}

nsresult
nsExpandedPrincipal::GetOriginInternal(nsACString& aOrigin)
{
  aOrigin.AssignLiteral("[Expanded Principal [");
  for (size_t i = 0; i < mPrincipals.Length(); ++i) {
    if (i != 0) {
      aOrigin.AppendLiteral(", ");
    }

    nsAutoCString subOrigin;
    nsresult rv = mPrincipals.ElementAt(i)->GetOrigin(subOrigin);
    NS_ENSURE_SUCCESS(rv, rv);
    aOrigin.Append(subOrigin);
  }

  aOrigin.Append("]]");
  return NS_OK;
}

bool
nsExpandedPrincipal::SubsumesInternal(nsIPrincipal* aOther,
                                      BasePrincipal::DocumentDomainConsideration aConsideration)
{
  // If aOther is an ExpandedPrincipal too, we break it down into its component
  // nsIPrincipals, and check subsumes on each one.
  nsCOMPtr<nsIExpandedPrincipal> expanded = do_QueryInterface(aOther);
  if (expanded) {
    nsTArray< nsCOMPtr<nsIPrincipal> >* otherList;
    expanded->GetWhiteList(&otherList);
    for (uint32_t i = 0; i < otherList->Length(); ++i){
      if (!SubsumesInternal((*otherList)[i], aConsideration)) {
        return false;
      }
    }
    return true;
  }

  // We're dealing with a regular principal. One of our principals must subsume
  // it.
  for (uint32_t i = 0; i < mPrincipals.Length(); ++i) {
    if (Cast(mPrincipals[i])->Subsumes(aOther, aConsideration)) {
      return true;
    }
  }

  return false;
}

NS_IMETHODIMP
nsExpandedPrincipal::CheckMayLoad(nsIURI* uri, bool aReport, bool aAllowIfInheritsPrincipal)
{
  nsresult rv;
  for (uint32_t i = 0; i < mPrincipals.Length(); ++i){
    rv = mPrincipals[i]->CheckMayLoad(uri, aReport, aAllowIfInheritsPrincipal);
    if (NS_SUCCEEDED(rv))
      return rv;
  }

  return NS_ERROR_DOM_BAD_URI;
}

NS_IMETHODIMP
nsExpandedPrincipal::GetHashValue(uint32_t* result)
{
  MOZ_CRASH("extended principal should never be used as key in a hash map");
}

NS_IMETHODIMP
nsExpandedPrincipal::GetURI(nsIURI** aURI)
{
  *aURI = nullptr;
  return NS_OK;
}

NS_IMETHODIMP
nsExpandedPrincipal::GetWhiteList(nsTArray<nsCOMPtr<nsIPrincipal> >** aWhiteList)
{
  *aWhiteList = &mPrincipals;
  return NS_OK;
}

NS_IMETHODIMP
nsExpandedPrincipal::GetBaseDomain(nsACString& aBaseDomain)
{
  return NS_ERROR_NOT_AVAILABLE;
}

bool
nsExpandedPrincipal::IsOnCSSUnprefixingWhitelist()
{
  // CSS Unprefixing Whitelist is a per-origin thing; doesn't really make sense
  // for an expanded principal. (And probably shouldn't be needed.)
  return false;
}


void
nsExpandedPrincipal::GetScriptLocation(nsACString& aStr)
{
  aStr.Assign("[Expanded Principal [");
  for (size_t i = 0; i < mPrincipals.Length(); ++i) {
    if (i != 0) {
      aStr.AppendLiteral(", ");
    }

    nsAutoCString spec;
    nsJSPrincipals::get(mPrincipals.ElementAt(i))->GetScriptLocation(spec);

    aStr.Append(spec);

  }
  aStr.Append("]]");
}

//////////////////////////////////////////
// Methods implementing nsISerializable //
//////////////////////////////////////////

NS_IMETHODIMP
nsExpandedPrincipal::Read(nsIObjectInputStream* aStream)
{
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsExpandedPrincipal::Write(nsIObjectOutputStream* aStream)
{
  return NS_ERROR_NOT_IMPLEMENTED;
}