/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "ClearSiteData.h"

#include "mozilla/OriginAttributes.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "mozilla/StaticPrefs.h"
#include "mozilla/Unused.h"
#include "nsASCIIMask.h"
#include "nsCharSeparatedTokenizer.h"
#include "nsContentUtils.h"
#include "nsIClearDataService.h"
#include "nsIHttpChannel.h"
#include "nsIHttpProtocolHandler.h"
#include "nsIObserverService.h"
#include "nsIPrincipal.h"
#include "nsIScriptError.h"
#include "nsNetUtil.h"

using namespace mozilla;

namespace {

StaticRefPtr<ClearSiteData> gClearSiteData;

} // anonymous

// This object is used to suspend/resume the channel.
class ClearSiteData::PendingCleanupHolder final
  : public nsIClearDataCallback
{
public:
  NS_DECL_ISUPPORTS

  explicit PendingCleanupHolder(nsIHttpChannel* aChannel)
    : mChannel(aChannel)
    , mPendingOp(false)
  {}

  nsresult
  Start()
  {
    MOZ_ASSERT(!mPendingOp);
    nsresult rv = mChannel->Suspend();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    mPendingOp = true;
    return NS_OK;
  }

  // This method must be called after any Start() call.
  void
  BrowsingContextsReloadNeeded(const nsACString& aOrigin)
  {
    mContextsReloadOrigin = aOrigin;
    MaybeBrowsingContextsReload();
  }

  // nsIClearDataCallback interface

  NS_IMETHOD
  OnDataDeleted(uint32_t aFailedFlags) override
  {
    MOZ_ASSERT(mPendingOp);
    mPendingOp = false;

    mChannel->Resume();
    mChannel = nullptr;

    MaybeBrowsingContextsReload();
    return NS_OK;
  }

private:
  ~PendingCleanupHolder()
  {
    if (mPendingOp) {
      mChannel->Resume();
    }
  }

  void
  MaybeBrowsingContextsReload()
  {
    if (mPendingOp || mContextsReloadOrigin.IsEmpty()) {
      return;
    }

    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
    if (NS_WARN_IF(!obs)) {
      return;
    }

    NS_ConvertUTF8toUTF16 origin(mContextsReloadOrigin);
    nsresult rv = obs->NotifyObservers(nullptr, "clear-site-data-reload-needed",
                                       origin.get());
    Unused << NS_WARN_IF(NS_FAILED(rv));
  }

  nsCOMPtr<nsIHttpChannel> mChannel;
  bool mPendingOp;
  nsCString mContextsReloadOrigin;
};

NS_INTERFACE_MAP_BEGIN(ClearSiteData::PendingCleanupHolder)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIClearDataCallback)
  NS_INTERFACE_MAP_ENTRY(nsIClearDataCallback)
NS_INTERFACE_MAP_END

NS_IMPL_ADDREF(ClearSiteData::PendingCleanupHolder)
NS_IMPL_RELEASE(ClearSiteData::PendingCleanupHolder)

/* static */ void
ClearSiteData::Initialize()
{
  MOZ_ASSERT(!gClearSiteData);
  MOZ_ASSERT(NS_IsMainThread());

  if (!XRE_IsParentProcess()) {
    return;
  }

  RefPtr<ClearSiteData> service = new ClearSiteData();

  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  if (NS_WARN_IF(!obs)) {
    return;
  }

  obs->AddObserver(service, NS_HTTP_ON_EXAMINE_RESPONSE_TOPIC, false);
  obs->AddObserver(service, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
  gClearSiteData = service;
}

/* static */ void
ClearSiteData::Shutdown()
{
  MOZ_ASSERT(NS_IsMainThread());

  if (!gClearSiteData) {
    return;
  }

  RefPtr<ClearSiteData> service = gClearSiteData;
  gClearSiteData = nullptr;

  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  if (NS_WARN_IF(!obs)) {
    return;
  }

  obs->RemoveObserver(service, NS_HTTP_ON_EXAMINE_RESPONSE_TOPIC);
  obs->RemoveObserver(service, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
}

ClearSiteData::ClearSiteData() = default;
ClearSiteData::~ClearSiteData() = default;

NS_IMETHODIMP
ClearSiteData::Observe(nsISupports* aSubject, const char* aTopic,
                       const char16_t* aData)
{
  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
    Shutdown();
    return NS_OK;
  }

  MOZ_ASSERT(!strcmp(aTopic, NS_HTTP_ON_EXAMINE_RESPONSE_TOPIC));

  // Pref disabled.
  if (!StaticPrefs::dom_clearSiteData_enabled()) {
    return NS_OK;
  }

  nsCOMPtr<nsIHttpChannel> channel = do_QueryInterface(aSubject);
  if (NS_WARN_IF(!channel)) {
    return NS_OK;
  }

  ClearDataFromChannel(channel);
  return NS_OK;
}

void
ClearSiteData::ClearDataFromChannel(nsIHttpChannel* aChannel)
{
  nsresult rv;
  nsCOMPtr<nsIURI> uri;

  // We want to use the final URI to check if Clear-Site-Data should be allowed
  // or not.
  rv = aChannel->GetURI(getter_AddRefs(uri));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return;
  }

  if (!IsSecureURI(uri)) {
    return;
  }

  uint32_t flags = ParseHeader(aChannel, uri);
  if (flags == 0) {
    // Nothing to do.
    return;
  }

  nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
  if (NS_WARN_IF(!ssm)) {
    return;
  }

  nsCOMPtr<nsIPrincipal> principal;
  rv = ssm->GetChannelURIPrincipal(aChannel, getter_AddRefs(principal));
  if (NS_WARN_IF(NS_FAILED(rv)) || !principal) {
    return;
  }

  int32_t cleanFlags = 0;
  RefPtr<PendingCleanupHolder> holder = new PendingCleanupHolder(aChannel);

  if (flags & eCache) {
    LogOpToConsole(aChannel, uri, eCache);
    cleanFlags |= nsIClearDataService::CLEAR_ALL_CACHES;
  }

  if (flags & eCookies) {
    LogOpToConsole(aChannel, uri, eCookies);
    cleanFlags |= nsIClearDataService::CLEAR_COOKIES;
  }

  if (flags & eStorage) {
    LogOpToConsole(aChannel, uri, eStorage);
    cleanFlags |= nsIClearDataService::CLEAR_DOM_STORAGES;
  }

  if (cleanFlags) {
    nsCOMPtr<nsIClearDataService> csd =
      do_GetService("@mozilla.org/clear-data-service;1");
    MOZ_ASSERT(csd);

    rv = holder->Start();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return;
    }

    rv = csd->DeleteDataFromPrincipal(principal,
                                      false /* user request */,
                                      cleanFlags, holder);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return;
    }
  }

  if (flags & eExecutionContexts) {
    LogOpToConsole(aChannel, uri, eExecutionContexts);
    BrowsingContextsReload(holder, principal);
  }
}

bool
ClearSiteData::IsSecureURI(nsIURI* aURI) const
{
  MOZ_ASSERT(aURI);

  bool prioriAuthenticated = false;
  if (NS_WARN_IF(NS_FAILED(NS_URIChainHasFlags(aURI,
                                               nsIProtocolHandler::URI_IS_POTENTIALLY_TRUSTWORTHY,
                                               &prioriAuthenticated)))) {
    return false;
  }

  return prioriAuthenticated;
}

uint32_t
ClearSiteData::ParseHeader(nsIHttpChannel* aChannel, nsIURI* aURI) const
{
  MOZ_ASSERT(aChannel);

  nsAutoCString headerValue;
  nsresult rv = aChannel->GetResponseHeader(NS_LITERAL_CSTRING("Clear-Site-Data"),
                                            headerValue);
  if (NS_FAILED(rv)) {
    return 0;
  }

  uint32_t flags = 0;

  nsCCharSeparatedTokenizer token(headerValue, ',');
  while (token.hasMoreTokens()) {
    auto value = token.nextToken();
    value.StripTaggedASCII(mozilla::ASCIIMask::MaskWhitespace());

    if (value.EqualsLiteral("\"cache\"")) {
      flags |= eCache;
      continue;
    }

    if (value.EqualsLiteral("\"cookies\"")) {
      flags |= eCookies;
      continue;
    }

    if (value.EqualsLiteral("\"storage\"")) {
      flags |= eStorage;
      continue;
    }

    if (value.EqualsLiteral("\"executionContexts\"")) {
      flags |= eExecutionContexts;
      continue;
    }

    if (value.EqualsLiteral("\"*\"")) {
      flags = eCache | eCookies | eStorage | eExecutionContexts;
      break;
    }

    LogErrorToConsole(aChannel, aURI, value);
  }

  return flags;
}

void
ClearSiteData::LogOpToConsole(nsIHttpChannel* aChannel, nsIURI* aURI,
                              Type aType) const
{
  nsAutoString type;
  TypeToString(aType, type);

  nsTArray<nsString> params;
  params.AppendElement(type);

  LogToConsoleInternal(aChannel, aURI, "RunningClearSiteDataValue", params);
}

void
ClearSiteData::LogErrorToConsole(nsIHttpChannel* aChannel,
                                 nsIURI* aURI,
                                 const nsACString& aUnknownType) const
{
  nsTArray<nsString> params;
  params.AppendElement(NS_ConvertUTF8toUTF16(aUnknownType));

  LogToConsoleInternal(aChannel, aURI, "UnknownClearSiteDataValue", params);
}

void
ClearSiteData::LogToConsoleInternal(nsIHttpChannel* aChannel, nsIURI* aURI,
                                    const char* aMsg,
                                    const nsTArray<nsString>& aParams) const
{
  MOZ_ASSERT(aChannel);
  MOZ_ASSERT(aURI);

  uint64_t windowID = 0;

  nsresult rv = aChannel->GetTopLevelContentWindowId(&windowID);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return;
  }

  if (!windowID) {
    nsCOMPtr<nsILoadGroup> loadGroup;
    nsresult rv = aChannel->GetLoadGroup(getter_AddRefs(loadGroup));
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return;
    }

    if (loadGroup) {
      windowID = nsContentUtils::GetInnerWindowID(loadGroup);
    }
  }

  nsAutoString localizedMsg;
  rv = nsContentUtils::FormatLocalizedString(nsContentUtils::eSECURITY_PROPERTIES,
                                             aMsg, aParams, localizedMsg);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return;
  }

  rv = nsContentUtils::ReportToConsoleByWindowID(localizedMsg,
                                                 nsIScriptError::infoFlag,
                                                 NS_LITERAL_CSTRING("Clear-Site-Data"),
                                                 windowID,
                                                 aURI);
  Unused << NS_WARN_IF(NS_FAILED(rv));
}

void
ClearSiteData::TypeToString(Type aType, nsAString& aStr) const
{
  switch (aType) {
  case eCache:
    aStr.AssignLiteral("cache");
    break;

  case eCookies:
    aStr.AssignLiteral("cookies");
    break;

  case eStorage:
    aStr.AssignLiteral("storage");
    break;

  case eExecutionContexts:
    aStr.AssignLiteral("executionContexts");
    break;

  default:
    MOZ_CRASH("Unknown type.");
  }
}

void
ClearSiteData::BrowsingContextsReload(PendingCleanupHolder* aHolder,
                                      nsIPrincipal* aPrincipal) const
{
  nsAutoCString origin;
  nsresult rv = aPrincipal->GetOrigin(origin);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return;
  }

  aHolder->BrowsingContextsReloadNeeded(origin);
}

NS_INTERFACE_MAP_BEGIN(ClearSiteData)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIObserver)
  NS_INTERFACE_MAP_ENTRY(nsIObserver)
NS_INTERFACE_MAP_END

NS_IMPL_ADDREF(ClearSiteData)
NS_IMPL_RELEASE(ClearSiteData)