/* -*- 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 "ExtensionProtocolHandler.h"

#include "mozilla/ClearOnShutdown.h"

#include "mozilla/dom/ContentChild.h"

#include "mozilla/ExtensionPolicyService.h"

#include "mozilla/FileUtils.h"

#include "mozilla/ipc/IPCStreamUtils.h"

#include "mozilla/ipc/URIParams.h"

#include "mozilla/ipc/URIUtils.h"

#include "mozilla/net/NeckoChild.h"

#include "mozilla/RefPtr.h"

#include "mozilla/ResultExtensions.h"

#include "FileDescriptor.h"

#include "FileDescriptorFile.h"

#include "LoadInfo.h"

#include "nsContentUtils.h"

#include "nsServiceManagerUtils.h"

#include "nsDirectoryServiceDefs.h"

#include "nsIFile.h"

#include "nsIFileChannel.h"

#include "nsIFileStreams.h"

#include "nsIFileURL.h"

#include "nsIJARChannel.h"

#include "nsIMIMEService.h"

#include "nsIURL.h"

#include "nsIChannel.h"

#include "nsIInputStreamPump.h"

#include "nsIJARURI.h"

#include "nsIStreamListener.h"

#include "nsIThread.h"

#include "nsIInputStream.h"

#include "nsIOutputStream.h"

#include "nsIStreamConverterService.h"

#include "nsNetUtil.h"

#include "prio.h"

#include "SimpleChannel.h"

#if defined(XP_WIN)

#include "nsILocalFileWin.h"

#include "WinUtils.h"

#endif

#define EXTENSION_SCHEME "moz-extension"

using mozilla::ipc::FileDescriptor;

using OptionalIPCStream = mozilla::ipc::OptionalIPCStream;

namespace mozilla {

namespace net {

using extensions::URLInfo;

LazyLogModule gExtProtocolLog("ExtProtocol");

#undef LOG

#define LOG(...) MOZ_LOG(gExtProtocolLog, LogLevel::Debug, (__VA_ARGS__))

StaticRefPtr<ExtensionProtocolHandler> ExtensionProtocolHandler::sSingleton;

/**

 * Helper class used with SimpleChannel to asynchronously obtain an input

 * stream or file descriptor from the parent for a remote moz-extension load

 * from the child.

 */

class ExtensionStreamGetter : public RefCounted<ExtensionStreamGetter>

{

  public:

    // To use when getting a remote input stream for a resource

    // in an unpacked extension.

    ExtensionStreamGetter(nsIURI* aURI, nsILoadInfo* aLoadInfo)

      : mURI(aURI)

      , mLoadInfo(aLoadInfo)

      , mIsJarChannel(false)

    {

      MOZ_ASSERT(aURI);

      MOZ_ASSERT(aLoadInfo);

      SetupEventTarget();

    }

    // To use when getting an FD for a packed extension JAR file

    // in order to load a resource.

    ExtensionStreamGetter(nsIURI* aURI, nsILoadInfo* aLoadInfo,

                          already_AddRefed<nsIJARChannel>&& aJarChannel,

                          nsIFile* aJarFile)

      : mURI(aURI)

      , mLoadInfo(aLoadInfo)

      , mJarChannel(std::move(aJarChannel))

      , mJarFile(aJarFile)

      , mIsJarChannel(true)

    {

      MOZ_ASSERT(aURI);

      MOZ_ASSERT(aLoadInfo);

      MOZ_ASSERT(mJarChannel);

      MOZ_ASSERT(aJarFile);

      SetupEventTarget();

    }

    ~ExtensionStreamGetter() = default;

    void SetupEventTarget()

    {

      mMainThreadEventTarget =

        nsContentUtils::GetEventTargetByLoadInfo(mLoadInfo, TaskCategory::Other);

      if (!mMainThreadEventTarget) {

        mMainThreadEventTarget = GetMainThreadSerialEventTarget();

      }

    }

    // Get an input stream or file descriptor from the parent asynchronously.

    Result<Ok, nsresult> GetAsync(nsIStreamListener* aListener,

                                  nsIChannel* aChannel);

    // Handle an input stream being returned from the parent

    void OnStream(already_AddRefed<nsIInputStream> aStream);

    // Handle file descriptor being returned from the parent

    void OnFD(const FileDescriptor& aFD);

    MOZ_DECLARE_REFCOUNTED_TYPENAME(ExtensionStreamGetter)

  private:

    nsCOMPtr<nsIURI> mURI;

    nsCOMPtr<nsILoadInfo> mLoadInfo;

    nsCOMPtr<nsIJARChannel> mJarChannel;

    nsCOMPtr<nsIFile> mJarFile;

    nsCOMPtr<nsIStreamListener> mListener;

    nsCOMPtr<nsIChannel> mChannel;

    nsCOMPtr<nsISerialEventTarget> mMainThreadEventTarget;

    bool mIsJarChannel;

};

class ExtensionJARFileOpener final : public nsISupports

{

public:

  ExtensionJARFileOpener(nsIFile* aFile,

                         NeckoParent::GetExtensionFDResolver& aResolve) :

    mFile(aFile),

    mResolve(aResolve)

  {

    MOZ_ASSERT(aFile);

    MOZ_ASSERT(aResolve);

  }

  NS_IMETHOD OpenFile()

  {

    MOZ_ASSERT(!NS_IsMainThread());

    AutoFDClose prFileDesc;

#if defined(XP_WIN)

    nsresult rv;

    nsCOMPtr<nsILocalFileWin> winFile = do_QueryInterface(mFile, &rv);

    MOZ_ASSERT(winFile);

    if (NS_SUCCEEDED(rv)) {

      rv = winFile->OpenNSPRFileDescShareDelete(PR_RDONLY, 0,

                                                &prFileDesc.rwget());

    }

#else

    nsresult rv = mFile->OpenNSPRFileDesc(PR_RDONLY, 0, &prFileDesc.rwget());

#endif /* XP_WIN */

    if (NS_SUCCEEDED(rv)) {

      mFD = FileDescriptor(FileDescriptor::PlatformHandleType(

                           PR_FileDesc2NativeHandle(prFileDesc)));

    }

    nsCOMPtr<nsIRunnable> event =

      mozilla::NewRunnableMethod("ExtensionJarFileFDResolver",

        this, &ExtensionJARFileOpener::SendBackFD);

    rv = NS_DispatchToMainThread(event, nsIEventTarget::DISPATCH_NORMAL);

    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "NS_DispatchToMainThread");

    return NS_OK;

  }

  NS_IMETHOD SendBackFD()

  {

    MOZ_ASSERT(NS_IsMainThread());

    mResolve(mFD);

    mResolve = nullptr;

    return NS_OK;

  }

  NS_DECL_THREADSAFE_ISUPPORTS

private:

  virtual ~ExtensionJARFileOpener() = default;

  nsCOMPtr<nsIFile> mFile;

  NeckoParent::GetExtensionFDResolver mResolve;

  FileDescriptor mFD;

};

NS_IMPL_ISUPPORTS(ExtensionJARFileOpener, nsISupports)

// The amount of time, in milliseconds, that the file opener thread will remain

// allocated after it is used. This value chosen because to match other uses

// of LazyIdleThread.

#define DEFAULT_THREAD_TIMEOUT_MS 30000

// Request an FD or input stream from the parent.

Result<Ok, nsresult>

ExtensionStreamGetter::GetAsync(nsIStreamListener* aListener,

                                nsIChannel* aChannel)

{

  MOZ_ASSERT(IsNeckoChild());

  MOZ_ASSERT(mMainThreadEventTarget);

  mListener = aListener;

  mChannel = aChannel;

  // Serialize the URI to send to parent

  mozilla::ipc::URIParams uri;

  SerializeURI(mURI, uri);

  RefPtr<ExtensionStreamGetter> self = this;

  if (mIsJarChannel) {

    // Request an FD for this moz-extension URI

    gNeckoChild->SendGetExtensionFD(uri)->Then(

      mMainThreadEventTarget,

      __func__,

      [self] (const FileDescriptor& fd) {

        self->OnFD(fd);

      },

      [self] (const mozilla::ipc::ResponseRejectReason) {

        self->OnFD(FileDescriptor());

      }

    );

    return Ok();

  }

  // Request an input stream for this moz-extension URI

  gNeckoChild->SendGetExtensionStream(uri)->Then(

    mMainThreadEventTarget,

    __func__,

    [self] (const RefPtr<nsIInputStream>& stream) {

      self->OnStream(do_AddRef(stream));

    },

    [self] (const mozilla::ipc::ResponseRejectReason) {

      self->OnStream(nullptr);

    }

  );

  return Ok();

}

static void

CancelRequest(nsIStreamListener* aListener,

              nsIChannel* aChannel,

              nsresult aResult)

{

  MOZ_ASSERT(aListener);

  MOZ_ASSERT(aChannel);

  aListener->OnStartRequest(aChannel, nullptr);

  aListener->OnStopRequest(aChannel, nullptr, aResult);

  aChannel->Cancel(NS_BINDING_ABORTED);

}

// Handle an input stream sent from the parent.

void

ExtensionStreamGetter::OnStream(already_AddRefed<nsIInputStream> aStream)

{

  MOZ_ASSERT(IsNeckoChild());

  MOZ_ASSERT(mListener);

  MOZ_ASSERT(mMainThreadEventTarget);

  nsCOMPtr<nsIInputStream> stream = std::move(aStream);

  // We must keep an owning reference to the listener

  // until we pass it on to AsyncRead.

  nsCOMPtr<nsIStreamListener> listener = mListener.forget();

  MOZ_ASSERT(mChannel);

  if (!stream) {

    // The parent didn't send us back a stream.

    CancelRequest(listener, mChannel, NS_ERROR_FILE_ACCESS_DENIED);

    return;

  }

  nsCOMPtr<nsIInputStreamPump> pump;

  nsresult rv = NS_NewInputStreamPump(getter_AddRefs(pump), stream.forget(),

                                      0, 0, false, mMainThreadEventTarget);

  if (NS_FAILED(rv)) {

    CancelRequest(listener, mChannel, rv);

    return;

  }

  rv = pump->AsyncRead(listener, nullptr);

  if (NS_FAILED(rv)) {

    CancelRequest(listener, mChannel, rv);

  }

}

// Handle an FD sent from the parent.

void

ExtensionStreamGetter::OnFD(const FileDescriptor& aFD)

{

  MOZ_ASSERT(IsNeckoChild());

  MOZ_ASSERT(mListener);

  MOZ_ASSERT(mChannel);

  if (!aFD.IsValid()) {

    OnStream(nullptr);

    return;

  }

  // We must keep an owning reference to the listener

  // until we pass it on to AsyncOpen2.

  nsCOMPtr<nsIStreamListener> listener = mListener.forget();

  RefPtr<FileDescriptorFile> fdFile = new FileDescriptorFile(aFD, mJarFile);

  mJarChannel->SetJarFile(fdFile);

  nsresult rv = mJarChannel->AsyncOpen2(listener);

  if (NS_FAILED(rv)) {

    CancelRequest(listener, mChannel, rv);

  }

}

NS_IMPL_QUERY_INTERFACE(ExtensionProtocolHandler, nsISubstitutingProtocolHandler,

                        nsIProtocolHandler, nsIProtocolHandlerWithDynamicFlags,

                        nsISupportsWeakReference)

NS_IMPL_ADDREF_INHERITED(ExtensionProtocolHandler, SubstitutingProtocolHandler)

NS_IMPL_RELEASE_INHERITED(ExtensionProtocolHandler, SubstitutingProtocolHandler)

already_AddRefed<ExtensionProtocolHandler>

ExtensionProtocolHandler::GetSingleton()

{

  if (!sSingleton) {

    sSingleton = new ExtensionProtocolHandler();

    ClearOnShutdown(&sSingleton);

  }

  return do_AddRef(sSingleton);

}

ExtensionProtocolHandler::ExtensionProtocolHandler()

  : SubstitutingProtocolHandler(EXTENSION_SCHEME)

#if !defined(XP_WIN)

#if defined(XP_MACOSX)

  , mAlreadyCheckedDevRepo(false)

#endif /* XP_MACOSX */

  , mAlreadyCheckedAppDir(false)

#endif /* ! XP_WIN */

{

  // Note, extensions.webextensions.protocol.remote=false is for

  // debugging purposes only. With process-level sandboxing, child

  // processes (specifically content and extension processes), will

  // not be able to load most moz-extension URI's when the pref is

  // set to false.

  mUseRemoteFileChannels = IsNeckoChild() &&

    Preferences::GetBool("extensions.webextensions.protocol.remote");

}

static inline ExtensionPolicyService&

EPS()

{

  return ExtensionPolicyService::GetSingleton();

}

nsresult

ExtensionProtocolHandler::GetFlagsForURI(nsIURI* aURI, uint32_t* aFlags)

{

  // In general a moz-extension URI is only loadable by chrome, but a whitelisted

  // subset are web-accessible (and cross-origin fetchable). Check that whitelist.

  bool loadableByAnyone = false;

  URLInfo url(aURI);

  if (auto* policy = EPS().GetByURL(url)) {

    loadableByAnyone = policy->IsPathWebAccessible(url.FilePath());

  }

  *aFlags = URI_STD | URI_IS_LOCAL_RESOURCE | URI_IS_POTENTIALLY_TRUSTWORTHY |

    (loadableByAnyone ? (URI_LOADABLE_BY_ANYONE |

                         URI_FETCHABLE_BY_ANYONE) : URI_DANGEROUS_TO_LOAD);

  return NS_OK;

}

bool

ExtensionProtocolHandler::ResolveSpecialCases(const nsACString& aHost,

                                              const nsACString& aPath,

                                              const nsACString& aPathname,

                                              nsACString& aResult)

{

  // Create special moz-extension:-pages such as moz-extension://foo/_blank.html

  // for all registered extensions. We can't just do this as a substitution

  // because substitutions can only match on host.

  if (!SubstitutingProtocolHandler::HasSubstitution(aHost)) {

    return false;

  }

  if (aPathname.EqualsLiteral("/_generated_background_page.html")) {

    Unused << EPS().GetGeneratedBackgroundPageUrl(aHost, aResult);

    return !aResult.IsEmpty();

  }

  return false;

}

// For file or JAR URI's, substitute in a remote channel.

Result<Ok, nsresult>

ExtensionProtocolHandler::SubstituteRemoteChannel(nsIURI* aURI,

                                                  nsILoadInfo* aLoadInfo,

                                                  nsIChannel** aRetVal)

{

  MOZ_ASSERT(IsNeckoChild());

  MOZ_TRY(aURI ? NS_OK : NS_ERROR_INVALID_ARG);

  MOZ_TRY(aLoadInfo ? NS_OK : NS_ERROR_INVALID_ARG);

  nsAutoCString unResolvedSpec;

  MOZ_TRY(aURI->GetSpec(unResolvedSpec));

  nsAutoCString resolvedSpec;

  MOZ_TRY(ResolveURI(aURI, resolvedSpec));

  // Use the target URI scheme to determine if this is a packed or unpacked

  // extension URI. For unpacked extensions, we'll request an input stream

  // from the parent. For a packed extension, we'll request a file descriptor

  // for the JAR file.

  nsAutoCString scheme;

  MOZ_TRY(net_ExtractURLScheme(resolvedSpec, scheme));

  if (scheme.EqualsLiteral("file")) {

    // Unpacked extension

    SubstituteRemoteFileChannel(aURI, aLoadInfo, resolvedSpec, aRetVal);

    return Ok();

  }

  if (scheme.EqualsLiteral("jar")) {

    // Packed extension

    return SubstituteRemoteJarChannel(aURI, aLoadInfo, resolvedSpec, aRetVal);

  }

  // Only unpacked resource files and JAR files are remoted.

  // No other moz-extension loads should be reading from the filesystem.

  return Ok();

}

nsresult

ExtensionProtocolHandler::SubstituteChannel(nsIURI* aURI,

                                            nsILoadInfo* aLoadInfo,

                                            nsIChannel** result)

{

  nsresult rv;

  nsCOMPtr<nsIURL> url = do_QueryInterface(aURI, &rv);

  NS_ENSURE_SUCCESS(rv, rv);

  if (mUseRemoteFileChannels) {

    MOZ_TRY(SubstituteRemoteChannel(aURI, aLoadInfo, result));

  }

  nsAutoCString ext;

  rv = url->GetFileExtension(ext);

  NS_ENSURE_SUCCESS(rv, rv);

  if (!ext.LowerCaseEqualsLiteral("css")) {

    return NS_OK;

  }

  // Filter CSS files to replace locale message tokens with localized strings.

  bool haveLoadInfo = aLoadInfo;

  nsCOMPtr<nsIChannel> channel = NS_NewSimpleChannel(

    aURI, aLoadInfo, *result,

    [haveLoadInfo] (nsIStreamListener* listener, nsIChannel* channel, nsIChannel* origChannel) -> RequestOrReason {

      nsresult rv;

      nsCOMPtr<nsIStreamConverterService> convService =

        do_GetService(NS_STREAMCONVERTERSERVICE_CONTRACTID, &rv);

      MOZ_TRY(rv);

      nsCOMPtr<nsIURI> uri;

      MOZ_TRY(channel->GetURI(getter_AddRefs(uri)));

      const char* kFromType = "application/vnd.mozilla.webext.unlocalized";

      const char* kToType = "text/css";

      nsCOMPtr<nsIStreamListener> converter;

      MOZ_TRY(convService->AsyncConvertData(kFromType, kToType, listener,

                                        uri, getter_AddRefs(converter)));

      if (haveLoadInfo) {

        MOZ_TRY(origChannel->AsyncOpen2(converter));

      } else {

        MOZ_TRY(origChannel->AsyncOpen(converter, nullptr));

      }

      return RequestOrReason(origChannel);

    });

  NS_ENSURE_TRUE(channel, NS_ERROR_OUT_OF_MEMORY);

  if (aLoadInfo) {

    nsCOMPtr<nsILoadInfo> loadInfo =

        static_cast<LoadInfo*>(aLoadInfo)->CloneForNewRequest();

    (*result)->SetLoadInfo(loadInfo);

  }

  channel.swap(*result);

  return NS_OK;

}

Result<Ok, nsresult>

ExtensionProtocolHandler::AllowExternalResource(nsIFile* aExtensionDir,

                                                nsIFile* aRequestedFile,

                                                bool* aResult)

{

  MOZ_ASSERT(!IsNeckoChild());

  MOZ_ASSERT(aResult);

  *aResult = false;

#if defined(XP_WIN)

  // On Windows, dev builds don't use symlinks so we never need to

  // allow a resource from outside of the extension dir.

  return Ok();

#else

  if (!mozilla::IsDevelopmentBuild()) {

    return Ok();

  }

  // On Mac and Linux unpackaged dev builds, system extensions use

  // symlinks to point to resources in the repo dir which we have to

  // allow loading. Before we allow an unpacked extension to load a

  // resource outside of the extension dir, we make sure the extension

  // dir is within the app directory.

  MOZ_TRY(AppDirContains(aExtensionDir, aResult));

  if (!*aResult) {

    return Ok();

  }

#if defined(XP_MACOSX)

  // Additionally, on Mac dev builds, we make sure that the requested

  // resource is within the repo dir. We don't perform this check on Linux

  // because we don't have a reliable path to the repo dir on Linux.

  MOZ_TRY(DevRepoContains(aRequestedFile, aResult));

#endif /* XP_MACOSX */

  return Ok();

#endif /* defined(XP_WIN) */

}

#if defined(XP_MACOSX)

// The |aRequestedFile| argument must already be Normalize()'d

Result<Ok, nsresult>

ExtensionProtocolHandler::DevRepoContains(nsIFile* aRequestedFile,

                                          bool* aResult)

{

  MOZ_ASSERT(mozilla::IsDevelopmentBuild());

  MOZ_ASSERT(!IsNeckoChild());

  MOZ_ASSERT(aResult);

  *aResult = false;

  // On the first invocation, set mDevRepo

  if (!mAlreadyCheckedDevRepo) {

    mAlreadyCheckedDevRepo = true;

    MOZ_TRY(mozilla::GetRepoDir(getter_AddRefs(mDevRepo)));

    if (MOZ_LOG_TEST(gExtProtocolLog, LogLevel::Debug)) {

      nsAutoCString repoPath;

      Unused << mDevRepo->GetNativePath(repoPath);

      LOG("Repo path: %s", repoPath.get());

    }

  }

  if (mDevRepo) {

    MOZ_TRY(mDevRepo->Contains(aRequestedFile, aResult));

  }

  return Ok();

}

#endif /* XP_MACOSX */

#if !defined(XP_WIN)

Result<Ok, nsresult>

ExtensionProtocolHandler::AppDirContains(nsIFile* aExtensionDir,

                                         bool* aResult)

{

  MOZ_ASSERT(mozilla::IsDevelopmentBuild());

  MOZ_ASSERT(!IsNeckoChild());

  MOZ_ASSERT(aResult);

  *aResult = false;

  // On the first invocation, set mAppDir

  if (!mAlreadyCheckedAppDir) {

    mAlreadyCheckedAppDir = true;

    MOZ_TRY(NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(mAppDir)));

    if (MOZ_LOG_TEST(gExtProtocolLog, LogLevel::Debug)) {

      nsAutoCString appDirPath;

      Unused << mAppDir->GetNativePath(appDirPath);

      LOG("AppDir path: %s", appDirPath.get());

    }

  }

  if (mAppDir) {

    MOZ_TRY(mAppDir->Contains(aExtensionDir, aResult));

  }

  return Ok();

}

#endif /* !defined(XP_WIN) */

static void

LogExternalResourceError(nsIFile* aExtensionDir, nsIFile* aRequestedFile)

{

  MOZ_ASSERT(aExtensionDir);

  MOZ_ASSERT(aRequestedFile);

  LOG("Rejecting external unpacked extension resource [%s] from "

      "extension directory [%s]", aRequestedFile->HumanReadablePath().get(),

      aExtensionDir->HumanReadablePath().get());

}

Result<nsCOMPtr<nsIInputStream>, nsresult>

ExtensionProtocolHandler::NewStream(nsIURI* aChildURI, bool* aTerminateSender)

{

  MOZ_ASSERT(!IsNeckoChild());

  MOZ_TRY(aChildURI ? NS_OK : NS_ERROR_INVALID_ARG);

  MOZ_TRY(aTerminateSender ? NS_OK : NS_ERROR_INVALID_ARG);

  *aTerminateSender = true;

  nsresult rv;

  // We should never receive a URI that isn't for a moz-extension because

  // these requests ordinarily come from the child's ExtensionProtocolHandler.

  // Ensure this request is for a moz-extension URI. A rogue child process

  // could send us any URI.

  bool isExtScheme = false;

  if (NS_FAILED(aChildURI->SchemeIs(EXTENSION_SCHEME, &isExtScheme)) ||

      !isExtScheme) {

    return Err(NS_ERROR_UNKNOWN_PROTOCOL);

  }

  // For errors after this point, we want to propagate the error to

  // the child, but we don't force the child to be terminated because

  // the error is likely to be due to a bug in the extension.

  *aTerminateSender = false;

  /*

   * Make sure there is a substitution installed for the host found

   * in the child's request URI and make sure the host resolves to

   * a directory.

   */

  nsAutoCString host;

  MOZ_TRY(aChildURI->GetAsciiHost(host));

  // Lookup the directory this host string resolves to

  nsCOMPtr<nsIURI> baseURI;

  MOZ_TRY(GetSubstitution(host, getter_AddRefs(baseURI)));

  // The result should be a file URL for the extension base dir

  nsCOMPtr<nsIFileURL> fileURL = do_QueryInterface(baseURI, &rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIFile> extensionDir;

  MOZ_TRY(fileURL->GetFile(getter_AddRefs(extensionDir)));

  bool isDirectory = false;

  MOZ_TRY(extensionDir->IsDirectory(&isDirectory));

  if (!isDirectory) {

    // The host should map to a directory for unpacked extensions

    return Err(NS_ERROR_FILE_NOT_DIRECTORY);

  }

  // Make sure the child URI resolves to a file URI then get a file

  // channel for the request. The resultant channel should be a

  // file channel because we only request remote streams for unpacked

  // extension resource loads where the URI resolves to a file.

  nsAutoCString resolvedSpec;

  MOZ_TRY(ResolveURI(aChildURI, resolvedSpec));

  nsAutoCString resolvedScheme;

  MOZ_TRY(net_ExtractURLScheme(resolvedSpec, resolvedScheme));

  if (!resolvedScheme.EqualsLiteral("file")) {

    return Err(NS_ERROR_UNEXPECTED);

  }

  nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIURI> resolvedURI;

  MOZ_TRY(ioService->NewURI(resolvedSpec,

                            nullptr,

                            nullptr,

                            getter_AddRefs(resolvedURI)));

  // We use the system principal to get a file channel for the request,

  // but only after we've checked (above) that the child URI is of

  // moz-extension scheme and that the URI host maps to a directory.

  nsCOMPtr<nsIChannel> channel;

  MOZ_TRY(NS_NewChannel(getter_AddRefs(channel),

                        resolvedURI,

                        nsContentUtils::GetSystemPrincipal(),

                        nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL,

                        nsIContentPolicy::TYPE_OTHER));

  nsCOMPtr<nsIFileChannel> fileChannel = do_QueryInterface(channel, &rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIFile> requestedFile;

  MOZ_TRY(fileChannel->GetFile(getter_AddRefs(requestedFile)));

  /*

   * Make sure the file we resolved to is within the extension directory.

   */

  // Normalize paths for sane comparisons. nsIFile::Contains depends on

  // it for reliable subpath checks.

  MOZ_TRY(extensionDir->Normalize());

  MOZ_TRY(requestedFile->Normalize());

#if defined(XP_WIN)

  if (!widget::WinUtils::ResolveJunctionPointsAndSymLinks(extensionDir) ||

      !widget::WinUtils::ResolveJunctionPointsAndSymLinks(requestedFile)) {

    return Err(NS_ERROR_FILE_ACCESS_DENIED);

  }

#endif

  bool isResourceFromExtensionDir = false;

  MOZ_TRY(extensionDir->Contains(requestedFile, &isResourceFromExtensionDir));

  if (!isResourceFromExtensionDir) {

    bool isAllowed = false;

    MOZ_TRY(AllowExternalResource(extensionDir, requestedFile, &isAllowed));

    if (!isAllowed) {

      LogExternalResourceError(extensionDir, requestedFile);

      return Err(NS_ERROR_FILE_ACCESS_DENIED);

    }

  }

  nsCOMPtr<nsIInputStream> inputStream;

  MOZ_TRY(NS_NewLocalFileInputStream(getter_AddRefs(inputStream),

                                     requestedFile,

                                     PR_RDONLY,

                                     -1,

                                     nsIFileInputStream::DEFER_OPEN));

  return inputStream;

}

Result<Ok, nsresult>

ExtensionProtocolHandler::NewFD(nsIURI* aChildURI,

                                bool* aTerminateSender,

                                NeckoParent::GetExtensionFDResolver& aResolve)

{

  MOZ_ASSERT(!IsNeckoChild());

  MOZ_TRY(aChildURI ? NS_OK : NS_ERROR_INVALID_ARG);

  MOZ_TRY(aTerminateSender ? NS_OK : NS_ERROR_INVALID_ARG);

  *aTerminateSender = true;

  nsresult rv;

  // Ensure this is a moz-extension URI

  bool isExtScheme = false;

  if (NS_FAILED(aChildURI->SchemeIs(EXTENSION_SCHEME, &isExtScheme)) ||

      !isExtScheme) {

    return Err(NS_ERROR_UNKNOWN_PROTOCOL);

  }

  // For errors after this point, we want to propagate the error to

  // the child, but we don't force the child to be terminated.

  *aTerminateSender = false;

  nsAutoCString host;

  MOZ_TRY(aChildURI->GetAsciiHost(host));

  // We expect the host string to map to a JAR file because the URI

  // should refer to a web accessible resource for an enabled extension.

  nsCOMPtr<nsIURI> subURI;

  MOZ_TRY(GetSubstitution(host, getter_AddRefs(subURI)));

  nsCOMPtr<nsIJARURI> jarURI = do_QueryInterface(subURI, &rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIURI> innerFileURI;

  MOZ_TRY(jarURI->GetJARFile(getter_AddRefs(innerFileURI)));

  nsCOMPtr<nsIFileURL> innerFileURL = do_QueryInterface(innerFileURI, &rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIFile> jarFile;

  MOZ_TRY(innerFileURL->GetFile(getter_AddRefs(jarFile)));

  if (!mFileOpenerThread) {

    mFileOpenerThread =

      new LazyIdleThread(DEFAULT_THREAD_TIMEOUT_MS,

                         NS_LITERAL_CSTRING("ExtensionProtocolHandler"));

  }

  RefPtr<ExtensionJARFileOpener> fileOpener =

    new ExtensionJARFileOpener(jarFile, aResolve);

  nsCOMPtr<nsIRunnable> event =

    mozilla::NewRunnableMethod("ExtensionJarFileOpener",

        fileOpener, &ExtensionJARFileOpener::OpenFile);

  MOZ_TRY(mFileOpenerThread->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL));

  return Ok();

}

// Set the channel's content type using the provided URI's type

void

SetContentType(nsIURI* aURI, nsIChannel* aChannel)

{

  nsresult rv;

  nsCOMPtr<nsIMIMEService> mime = do_GetService("@mozilla.org/mime;1", &rv);

  if (NS_SUCCEEDED(rv)) {

    nsAutoCString contentType;

    rv = mime->GetTypeFromURI(aURI, contentType);

    if (NS_SUCCEEDED(rv)) {

      Unused << aChannel->SetContentType(contentType);

    }

  }

}

// Gets a SimpleChannel that wraps the provided ExtensionStreamGetter

static void

NewSimpleChannel(nsIURI* aURI,

                 nsILoadInfo* aLoadinfo,

                 ExtensionStreamGetter* aStreamGetter,

                 nsIChannel** aRetVal)

{

  nsCOMPtr<nsIChannel> channel = NS_NewSimpleChannel(

    aURI, aLoadinfo, aStreamGetter,

    [] (nsIStreamListener* listener, nsIChannel* simpleChannel,

        ExtensionStreamGetter* getter) -> RequestOrReason {

      MOZ_TRY(getter->GetAsync(listener, simpleChannel));

      return RequestOrReason(nullptr);

    });

  SetContentType(aURI, channel);

  channel.swap(*aRetVal);

}

// Gets a SimpleChannel that wraps the provided channel

static void

NewSimpleChannel(nsIURI* aURI,

                 nsILoadInfo* aLoadinfo,

                 nsIChannel* aChannel,

                 nsIChannel** aRetVal)

{

  nsCOMPtr<nsIChannel> channel = NS_NewSimpleChannel(aURI, aLoadinfo, aChannel,

    [] (nsIStreamListener* listener, nsIChannel* simpleChannel,

        nsIChannel* origChannel) -> RequestOrReason {

      nsresult rv = origChannel->AsyncOpen2(listener);

      if (NS_FAILED(rv)) {

        simpleChannel->Cancel(NS_BINDING_ABORTED);

        return RequestOrReason(rv);

      }

      return RequestOrReason(origChannel);

    });

  SetContentType(aURI, channel);

  channel.swap(*aRetVal);

}

void

ExtensionProtocolHandler::SubstituteRemoteFileChannel(nsIURI* aURI,

                                                      nsILoadInfo* aLoadinfo,

                                                      nsACString& aResolvedFileSpec,

                                                      nsIChannel** aRetVal)

{

  MOZ_ASSERT(IsNeckoChild());

  RefPtr<ExtensionStreamGetter> streamGetter =

    new ExtensionStreamGetter(aURI, aLoadinfo);

  NewSimpleChannel(aURI, aLoadinfo, streamGetter, aRetVal);

}

static Result<Ok, nsresult>

LogCacheCheck(const nsIJARChannel* aJarChannel,

              nsIJARURI* aJarURI,

              bool aIsCached)

{

  nsresult rv;

  nsCOMPtr<nsIURI> innerFileURI;

  MOZ_TRY(aJarURI->GetJARFile(getter_AddRefs(innerFileURI)));

  nsCOMPtr<nsIFileURL> innerFileURL = do_QueryInterface(innerFileURI, &rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIFile> jarFile;

  MOZ_TRY(innerFileURL->GetFile(getter_AddRefs(jarFile)));

  nsAutoCString uriSpec, jarSpec;

  Unused << aJarURI->GetSpec(uriSpec);

  Unused << innerFileURI->GetSpec(jarSpec);

  LOG("[JARChannel %p] Cache %s: %s (%s)",

      aJarChannel, aIsCached ? "hit" : "miss", uriSpec.get(), jarSpec.get());

  return Ok();

}

Result<Ok, nsresult>

ExtensionProtocolHandler::SubstituteRemoteJarChannel(nsIURI* aURI,

                                                     nsILoadInfo* aLoadinfo,

                                                     nsACString& aResolvedSpec,

                                                     nsIChannel** aRetVal)

{

  MOZ_ASSERT(IsNeckoChild());

  nsresult rv;

  // Build a JAR URI for this jar:file:// URI and use it to extract the

  // inner file URI.

  nsCOMPtr<nsIURI> uri;

  MOZ_TRY(NS_NewURI(getter_AddRefs(uri), aResolvedSpec));

  nsCOMPtr<nsIJARURI> jarURI = do_QueryInterface(uri, &rv);

  MOZ_TRY(rv);

  nsCOMPtr<nsIJARChannel> jarChannel = do_QueryInterface(*aRetVal, &rv);

  MOZ_TRY(rv);

  bool isCached = false;