ExpandedPrincipal.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 "ExpandedPrincipal.h"
#include "nsIClassInfoImpl.h"

using namespace mozilla;

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

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

  bool Equals(nsIPrincipal* a, nsIPrincipal* b) const
  {
    nsAutoCString originA;
    DebugOnly<nsresult> rv = a->GetOrigin(originA);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
    nsAutoCString originB;
    rv = b->GetOrigin(originB);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
    return a == b;
  }
};

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

ExpandedPrincipal::ExpandedPrincipal()
  : BasePrincipal(eExpandedPrincipal)
{
}

ExpandedPrincipal::~ExpandedPrincipal()
{ }

already_AddRefed<ExpandedPrincipal>
ExpandedPrincipal::Create(nsTArray<nsCOMPtr<nsIPrincipal>>& aWhiteList,
                          const OriginAttributes& aAttrs)
{
  RefPtr<ExpandedPrincipal> ep = new ExpandedPrincipal(aWhiteList);

  nsAutoCString origin;
  origin.AssignLiteral("[Expanded Principal [");
  for (size_t i = 0; i < ep->mPrincipals.Length(); ++i) {
    if (i != 0) {
      origin.AppendLiteral(", ");
    }

    nsAutoCString subOrigin;
    DebugOnly<nsresult> rv = ep->mPrincipals.ElementAt(i)->GetOrigin(subOrigin);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
    origin.Append(subOrigin);
  }
  origin.AppendLiteral("]]");

  ep->FinishInit(origin, aAttrs);
  return ep.forget();
}

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

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

bool
ExpandedPrincipal::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.
  if (Cast(aOther)->Is<ExpandedPrincipal>()) {
    auto* expanded = Cast(aOther)->As<ExpandedPrincipal>();

    for (auto& other : expanded->WhiteList()) {
      // Use SubsumesInternal rather than Subsumes here, since OriginAttribute
      // checks are only done between non-expanded sub-principals, and we don't
      // need to incur the extra virtual call overhead.
      if (!SubsumesInternal(other, 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;
}

bool
ExpandedPrincipal::MayLoadInternal(nsIURI* uri)
{
  for (uint32_t i = 0; i < mPrincipals.Length(); ++i){
    if (BasePrincipal::Cast(mPrincipals[i])->MayLoadInternal(uri)) {
      return true;
    }
  }

  return false;
}

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

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

const nsTArray<nsCOMPtr<nsIPrincipal>>&
ExpandedPrincipal::WhiteList()
{
  return mPrincipals;
}

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

NS_IMETHODIMP
ExpandedPrincipal::GetAddonId(nsAString& aAddonId)
{
  aAddonId.Truncate();
  return NS_OK;
};

bool
ExpandedPrincipal::AddonHasPermission(const nsAtom* aPerm)
{
  for (size_t i = 0; i < mPrincipals.Length(); ++i) {
    if (BasePrincipal::Cast(mPrincipals[i])->AddonHasPermission(aPerm)) {
      return true;
    }
  }
  return false;
}

bool
ExpandedPrincipal::AddonAllowsLoad(nsIURI* aURI, bool aExplicit /* = false */)
{
  for (const auto& principal : mPrincipals) {
    if (Cast(principal)->AddonAllowsLoad(aURI, aExplicit)) {
      return true;
    }
  }
  return false;
}

nsIPrincipal*
ExpandedPrincipal::PrincipalToInherit(nsIURI* aRequestedURI)
{
  if (aRequestedURI) {
    // If a given sub-principal subsumes the given URI, use that principal for
    // inheritance. In general, this only happens with certain CORS modes, loads
    // with forced principal inheritance, and creation of XML documents from
    // XMLHttpRequests or fetch requests. For URIs that normally inherit a
    // principal (such as data: URIs), we fall back to the last principal in the
    // whitelist.
    for (const auto& principal : mPrincipals) {
      if (Cast(principal)->MayLoadInternal(aRequestedURI)) {
        return principal;
      }
    }
  }
  return mPrincipals.LastElement();
}

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

    nsAutoCString spec;
    nsresult rv =
      nsJSPrincipals::get(mPrincipals.ElementAt(i))->GetScriptLocation(spec);
    NS_ENSURE_SUCCESS(rv, rv);

    aStr.Append(spec);
  }
  aStr.AppendLiteral("]]");
  return NS_OK;
}

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

// We've had way too many issues with unversioned serializations, so
// explicitly version this one.
static const uint32_t kSerializationVersion = 1;

NS_IMETHODIMP
ExpandedPrincipal::Read(nsIObjectInputStream* aStream)
{
  uint32_t version;
  nsresult rv = aStream->Read32(&version);
  if (version != kSerializationVersion) {
    MOZ_ASSERT(false,
               "We really need to add handling of the old(?) version here");
    return NS_ERROR_UNEXPECTED;
  }

  uint32_t count;
  rv = aStream->Read32(&count);
  if (NS_FAILED(rv)) {
    return rv;
  }

  if (!mPrincipals.SetCapacity(count, fallible)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  OriginComparator c;
  for (uint32_t i = 0; i < count; ++i) {
    nsCOMPtr<nsISupports> read;
    rv = aStream->ReadObject(true, getter_AddRefs(read));
    if (NS_FAILED(rv)) {
      return rv;
    }

    nsCOMPtr<nsIPrincipal> principal = do_QueryInterface(read);
    if (!principal) {
      return NS_ERROR_UNEXPECTED;
    }

    // Play it safe and InsertElementSorted, in case the sort order
    // changed for some bizarre reason.
    mPrincipals.InsertElementSorted(std::move(principal), c);
  }

  return NS_OK;
}

NS_IMETHODIMP
ExpandedPrincipal::Write(nsIObjectOutputStream* aStream)
{
  nsresult rv = aStream->Write32(kSerializationVersion);
  if (NS_FAILED(rv)) {
    return rv;
  }

  rv = aStream->Write32(mPrincipals.Length());
  if (NS_FAILED(rv)) {
    return rv;
  }

  for (auto& principal : mPrincipals) {
    rv = aStream->WriteObject(principal, true);
    if (NS_FAILED(rv)) {
      return rv;
    }
  }

  return NS_OK;
}