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| -rw-r--r-- | netwerk/base/BackgroundFileSaver.cpp | 1113 |
1 files changed, 1113 insertions, 0 deletions
diff --git a/netwerk/base/BackgroundFileSaver.cpp b/netwerk/base/BackgroundFileSaver.cpp new file mode 100644 index 0000000000..a5d41faf95 --- /dev/null +++ b/netwerk/base/BackgroundFileSaver.cpp @@ -0,0 +1,1113 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=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 "BackgroundFileSaver.h" + +#include "ScopedNSSTypes.h" +#include "mozilla/ArrayAlgorithm.h" +#include "mozilla/Casting.h" +#include "mozilla/Logging.h" +#include "mozilla/ScopeExit.h" +#include "mozilla/Telemetry.h" +#include "nsCOMArray.h" +#include "nsComponentManagerUtils.h" +#include "nsDependentSubstring.h" +#include "nsIAsyncInputStream.h" +#include "nsIFile.h" +#include "nsIMutableArray.h" +#include "nsIPipe.h" +#include "nsNetUtil.h" +#include "nsThreadUtils.h" +#include "pk11pub.h" +#include "secoidt.h" + +#ifdef XP_WIN +# include <windows.h> +# include <softpub.h> +# include <wintrust.h> +#endif // XP_WIN + +namespace mozilla { +namespace net { + +// MOZ_LOG=BackgroundFileSaver:5 +static LazyLogModule prlog("BackgroundFileSaver"); +#define LOG(args) MOZ_LOG(prlog, mozilla::LogLevel::Debug, args) +#define LOG_ENABLED() MOZ_LOG_TEST(prlog, mozilla::LogLevel::Debug) + +//////////////////////////////////////////////////////////////////////////////// +//// Globals + +/** + * Buffer size for writing to the output file or reading from the input file. + */ +#define BUFFERED_IO_SIZE (1024 * 32) + +/** + * When this upper limit is reached, the original request is suspended. + */ +#define REQUEST_SUSPEND_AT (1024 * 1024 * 4) + +/** + * When this lower limit is reached, the original request is resumed. + */ +#define REQUEST_RESUME_AT (1024 * 1024 * 2) + +//////////////////////////////////////////////////////////////////////////////// +//// NotifyTargetChangeRunnable + +/** + * Runnable object used to notify the control thread that file contents will now + * be saved to the specified file. + */ +class NotifyTargetChangeRunnable final : public Runnable { + public: + NotifyTargetChangeRunnable(BackgroundFileSaver* aSaver, nsIFile* aTarget) + : Runnable("net::NotifyTargetChangeRunnable"), + mSaver(aSaver), + mTarget(aTarget) {} + + NS_IMETHOD Run() override { return mSaver->NotifyTargetChange(mTarget); } + + private: + RefPtr<BackgroundFileSaver> mSaver; + nsCOMPtr<nsIFile> mTarget; +}; + +//////////////////////////////////////////////////////////////////////////////// +//// BackgroundFileSaver + +uint32_t BackgroundFileSaver::sThreadCount = 0; +uint32_t BackgroundFileSaver::sTelemetryMaxThreadCount = 0; + +BackgroundFileSaver::BackgroundFileSaver() { + LOG(("Created BackgroundFileSaver [this = %p]", this)); +} + +BackgroundFileSaver::~BackgroundFileSaver() { + LOG(("Destroying BackgroundFileSaver [this = %p]", this)); +} + +// Called on the control thread. +nsresult BackgroundFileSaver::Init() { + MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread"); + + NS_NewPipe2(getter_AddRefs(mPipeInputStream), + getter_AddRefs(mPipeOutputStream), true, true, 0, + HasInfiniteBuffer() ? UINT32_MAX : 0); + + mControlEventTarget = GetCurrentEventTarget(); + NS_ENSURE_TRUE(mControlEventTarget, NS_ERROR_NOT_INITIALIZED); + + nsresult rv = NS_CreateBackgroundTaskQueue("BgFileSaver", + getter_AddRefs(mBackgroundET)); + NS_ENSURE_SUCCESS(rv, rv); + + sThreadCount++; + if (sThreadCount > sTelemetryMaxThreadCount) { + sTelemetryMaxThreadCount = sThreadCount; + } + + return NS_OK; +} + +// Called on the control thread. +NS_IMETHODIMP +BackgroundFileSaver::GetObserver(nsIBackgroundFileSaverObserver** aObserver) { + NS_ENSURE_ARG_POINTER(aObserver); + *aObserver = do_AddRef(mObserver).take(); + return NS_OK; +} + +// Called on the control thread. +NS_IMETHODIMP +BackgroundFileSaver::SetObserver(nsIBackgroundFileSaverObserver* aObserver) { + mObserver = aObserver; + return NS_OK; +} + +// Called on the control thread. +NS_IMETHODIMP +BackgroundFileSaver::EnableAppend() { + MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread"); + + MutexAutoLock lock(mLock); + mAppend = true; + + return NS_OK; +} + +// Called on the control thread. +NS_IMETHODIMP +BackgroundFileSaver::SetTarget(nsIFile* aTarget, bool aKeepPartial) { + NS_ENSURE_ARG(aTarget); + { + MutexAutoLock lock(mLock); + if (!mInitialTarget) { + aTarget->Clone(getter_AddRefs(mInitialTarget)); + mInitialTargetKeepPartial = aKeepPartial; + } else { + aTarget->Clone(getter_AddRefs(mRenamedTarget)); + mRenamedTargetKeepPartial = aKeepPartial; + } + } + + // After the worker thread wakes up because attention is requested, it will + // rename or create the target file as requested, and start copying data. + return GetWorkerThreadAttention(true); +} + +// Called on the control thread. +NS_IMETHODIMP +BackgroundFileSaver::Finish(nsresult aStatus) { + nsresult rv; + + // This will cause the NS_AsyncCopy operation, if it's in progress, to consume + // all the data that is still in the pipe, and then finish. + rv = mPipeOutputStream->Close(); + NS_ENSURE_SUCCESS(rv, rv); + + // Ensure that, when we get attention from the worker thread, if no pending + // rename operation is waiting, the operation will complete. + { + MutexAutoLock lock(mLock); + mFinishRequested = true; + if (NS_SUCCEEDED(mStatus)) { + mStatus = aStatus; + } + } + + // After the worker thread wakes up because attention is requested, it will + // process the completion conditions, detect that completion is requested, and + // notify the main thread of the completion. If this function was called with + // a success code, we wait for the copy to finish before processing the + // completion conditions, otherwise we interrupt the copy immediately. + return GetWorkerThreadAttention(NS_FAILED(aStatus)); +} + +NS_IMETHODIMP +BackgroundFileSaver::EnableSha256() { + MOZ_ASSERT(NS_IsMainThread(), + "Can't enable sha256 or initialize NSS off the main thread"); + // Ensure Personal Security Manager is initialized. This is required for + // PK11_* operations to work. + nsresult rv; + nsCOMPtr<nsISupports> nssDummy = do_GetService("@mozilla.org/psm;1", &rv); + NS_ENSURE_SUCCESS(rv, rv); + MutexAutoLock lock(mLock); + mSha256Enabled = true; // this will be read by the worker thread + return NS_OK; +} + +NS_IMETHODIMP +BackgroundFileSaver::GetSha256Hash(nsACString& aHash) { + MOZ_ASSERT(NS_IsMainThread(), "Can't inspect sha256 off the main thread"); + // We acquire a lock because mSha256 is written on the worker thread. + MutexAutoLock lock(mLock); + if (mSha256.IsEmpty()) { + return NS_ERROR_NOT_AVAILABLE; + } + aHash = mSha256; + return NS_OK; +} + +NS_IMETHODIMP +BackgroundFileSaver::EnableSignatureInfo() { + MOZ_ASSERT(NS_IsMainThread(), + "Can't enable signature extraction off the main thread"); + // Ensure Personal Security Manager is initialized. + nsresult rv; + nsCOMPtr<nsISupports> nssDummy = do_GetService("@mozilla.org/psm;1", &rv); + NS_ENSURE_SUCCESS(rv, rv); + MutexAutoLock lock(mLock); + mSignatureInfoEnabled = true; + return NS_OK; +} + +NS_IMETHODIMP +BackgroundFileSaver::GetSignatureInfo( + nsTArray<nsTArray<nsTArray<uint8_t>>>& aSignatureInfo) { + MOZ_ASSERT(NS_IsMainThread(), "Can't inspect signature off the main thread"); + // We acquire a lock because mSignatureInfo is written on the worker thread. + MutexAutoLock lock(mLock); + if (!mComplete || !mSignatureInfoEnabled) { + return NS_ERROR_NOT_AVAILABLE; + } + for (const auto& signatureChain : mSignatureInfo) { + aSignatureInfo.AppendElement(TransformIntoNewArray( + signatureChain, [](const auto& element) { return element.Clone(); })); + } + return NS_OK; +} + +// Called on the control thread. +nsresult BackgroundFileSaver::GetWorkerThreadAttention( + bool aShouldInterruptCopy) { + nsresult rv; + + MutexAutoLock lock(mLock); + + // We only require attention one time. If this function is called two times + // before the worker thread wakes up, and the first has aShouldInterruptCopy + // false and the second true, we won't forcibly interrupt the copy from the + // control thread. However, that never happens, because calling Finish with a + // success code is the only case that may result in aShouldInterruptCopy being + // false. In that case, we won't call this function again, because consumers + // should not invoke other methods on the control thread after calling Finish. + // And in any case, Finish already closes one end of the pipe, causing the + // copy to finish properly on its own. + if (mWorkerThreadAttentionRequested) { + return NS_OK; + } + + if (!mAsyncCopyContext) { + // Background event queues are not shutdown and could be called after + // the queue is reset to null. To match the behavior of nsIThread + // return NS_ERROR_UNEXPECTED + if (!mBackgroundET) { + return NS_ERROR_UNEXPECTED; + } + + // Copy is not in progress, post an event to handle the change manually. + rv = mBackgroundET->Dispatch( + NewRunnableMethod("net::BackgroundFileSaver::ProcessAttention", this, + &BackgroundFileSaver::ProcessAttention), + NS_DISPATCH_EVENT_MAY_BLOCK); + NS_ENSURE_SUCCESS(rv, rv); + + } else if (aShouldInterruptCopy) { + // Interrupt the copy. The copy will be resumed, if needed, by the + // ProcessAttention function, invoked by the AsyncCopyCallback function. + NS_CancelAsyncCopy(mAsyncCopyContext, NS_ERROR_ABORT); + } + + // Indicate that attention has been requested successfully, there is no need + // to post another event until the worker thread processes the current one. + mWorkerThreadAttentionRequested = true; + + return NS_OK; +} + +// Called on the worker thread. +// static +void BackgroundFileSaver::AsyncCopyCallback(void* aClosure, nsresult aStatus) { + // We called NS_ADDREF_THIS when NS_AsyncCopy started, to keep the object + // alive even if other references disappeared. At the end of this method, + // we've finished using the object and can safely release our reference. + RefPtr<BackgroundFileSaver> self = + dont_AddRef((BackgroundFileSaver*)aClosure); + { + MutexAutoLock lock(self->mLock); + + // Now that the copy was interrupted or terminated, any notification from + // the control thread requires an event to be posted to the worker thread. + self->mAsyncCopyContext = nullptr; + + // When detecting failures, ignore the status code we use to interrupt. + if (NS_FAILED(aStatus) && aStatus != NS_ERROR_ABORT && + NS_SUCCEEDED(self->mStatus)) { + self->mStatus = aStatus; + } + } + + (void)self->ProcessAttention(); +} + +// Called on the worker thread. +nsresult BackgroundFileSaver::ProcessAttention() { + nsresult rv; + + // This function is called whenever the attention of the worker thread has + // been requested. This may happen in these cases: + // * We are about to start the copy for the first time. In this case, we are + // called from an event posted on the worker thread from the control thread + // by GetWorkerThreadAttention, and mAsyncCopyContext is null. + // * We have interrupted the copy for some reason. In this case, we are + // called by AsyncCopyCallback, and mAsyncCopyContext is null. + // * We are currently executing ProcessStateChange, and attention is requested + // by the control thread, for example because SetTarget or Finish have been + // called. In this case, we are called from from an event posted through + // GetWorkerThreadAttention. While mAsyncCopyContext was always null when + // the event was posted, at this point mAsyncCopyContext may not be null + // anymore, because ProcessStateChange may have started the copy before the + // event that called this function was processed on the worker thread. + // If mAsyncCopyContext is not null, we interrupt the copy and re-enter + // through AsyncCopyCallback. This allows us to check if, for instance, we + // should rename the target file. We will then restart the copy if needed. + + // mAsyncCopyContext is only written on the worker thread (which we are on) + MOZ_ASSERT(!NS_IsMainThread()); + { + // Even though we're the only thread that writes this, we have to take the + // lock + MutexAutoLock lock(mLock); + if (mAsyncCopyContext) { + NS_CancelAsyncCopy(mAsyncCopyContext, NS_ERROR_ABORT); + return NS_OK; + } + } + // Use the current shared state to determine the next operation to execute. + rv = ProcessStateChange(); + if (NS_FAILED(rv)) { + // If something failed while processing, terminate the operation now. + { + MutexAutoLock lock(mLock); + + if (NS_SUCCEEDED(mStatus)) { + mStatus = rv; + } + } + // Ensure we notify completion now that the operation failed. + CheckCompletion(); + } + + return NS_OK; +} + +// Called on the worker thread. +nsresult BackgroundFileSaver::ProcessStateChange() { + nsresult rv; + + // We might have been notified because the operation is complete, verify. + if (CheckCompletion()) { + return NS_OK; + } + + // Get a copy of the current shared state for the worker thread. + nsCOMPtr<nsIFile> initialTarget; + bool initialTargetKeepPartial; + nsCOMPtr<nsIFile> renamedTarget; + bool renamedTargetKeepPartial; + bool sha256Enabled; + bool append; + { + MutexAutoLock lock(mLock); + + initialTarget = mInitialTarget; + initialTargetKeepPartial = mInitialTargetKeepPartial; + renamedTarget = mRenamedTarget; + renamedTargetKeepPartial = mRenamedTargetKeepPartial; + sha256Enabled = mSha256Enabled; + append = mAppend; + + // From now on, another attention event needs to be posted if state changes. + mWorkerThreadAttentionRequested = false; + } + + // The initial target can only be null if it has never been assigned. In this + // case, there is nothing to do since we never created any output file. + if (!initialTarget) { + return NS_OK; + } + + // Determine if we are processing the attention request for the first time. + bool isContinuation = !!mActualTarget; + if (!isContinuation) { + // Assign the target file for the first time. + mActualTarget = initialTarget; + mActualTargetKeepPartial = initialTargetKeepPartial; + } + + // Verify whether we have actually been instructed to use a different file. + // This may happen the first time this function is executed, if SetTarget was + // called two times before the worker thread processed the attention request. + bool equalToCurrent = false; + if (renamedTarget) { + rv = mActualTarget->Equals(renamedTarget, &equalToCurrent); + NS_ENSURE_SUCCESS(rv, rv); + if (!equalToCurrent) { + // If we were asked to rename the file but the initial file did not exist, + // we simply create the file in the renamed location. We avoid this check + // if we have already started writing the output file ourselves. + bool exists = true; + if (!isContinuation) { + rv = mActualTarget->Exists(&exists); + NS_ENSURE_SUCCESS(rv, rv); + } + if (exists) { + // We are moving the previous target file to a different location. + nsCOMPtr<nsIFile> renamedTargetParentDir; + rv = renamedTarget->GetParent(getter_AddRefs(renamedTargetParentDir)); + NS_ENSURE_SUCCESS(rv, rv); + + nsAutoString renamedTargetName; + rv = renamedTarget->GetLeafName(renamedTargetName); + NS_ENSURE_SUCCESS(rv, rv); + + // We must delete any existing target file before moving the current + // one. + rv = renamedTarget->Exists(&exists); + NS_ENSURE_SUCCESS(rv, rv); + if (exists) { + rv = renamedTarget->Remove(false); + NS_ENSURE_SUCCESS(rv, rv); + } + + // Move the file. If this fails, we still reference the original file + // in mActualTarget, so that it is deleted if requested. If this + // succeeds, the nsIFile instance referenced by mActualTarget mutates + // and starts pointing to the new file, but we'll discard the reference. + rv = mActualTarget->MoveTo(renamedTargetParentDir, renamedTargetName); + NS_ENSURE_SUCCESS(rv, rv); + } + + // We should not only update the mActualTarget with renameTarget when + // they point to the different files. + // In this way, if mActualTarget and renamedTarget point to the same file + // with different addresses, "CheckCompletion()" will return false + // forever. + } + + // Update mActualTarget with renameTarget, + // even if they point to the same file. + mActualTarget = renamedTarget; + mActualTargetKeepPartial = renamedTargetKeepPartial; + } + + // Notify if the target file name actually changed. + if (!equalToCurrent) { + // We must clone the nsIFile instance because mActualTarget is not + // immutable, it may change if the target is renamed later. + nsCOMPtr<nsIFile> actualTargetToNotify; + rv = mActualTarget->Clone(getter_AddRefs(actualTargetToNotify)); + NS_ENSURE_SUCCESS(rv, rv); + + RefPtr<NotifyTargetChangeRunnable> event = + new NotifyTargetChangeRunnable(this, actualTargetToNotify); + NS_ENSURE_TRUE(event, NS_ERROR_FAILURE); + + rv = mControlEventTarget->Dispatch(event, NS_DISPATCH_NORMAL); + NS_ENSURE_SUCCESS(rv, rv); + } + + if (isContinuation) { + // The pending rename operation might be the last task before finishing. We + // may return here only if we have already created the target file. + if (CheckCompletion()) { + return NS_OK; + } + + // Even if the operation did not complete, the pipe input stream may be + // empty and may have been closed already. We detect this case using the + // Available property, because it never returns an error if there is more + // data to be consumed. If the pipe input stream is closed, we just exit + // and wait for more calls like SetTarget or Finish to be invoked on the + // control thread. However, we still truncate the file or create the + // initial digest context if we are expected to do that. + uint64_t available; + rv = mPipeInputStream->Available(&available); + if (NS_FAILED(rv)) { + return NS_OK; + } + } + + // Create the digest if requested and NSS hasn't been shut down. + if (sha256Enabled && mDigest.isNothing()) { + mDigest.emplace(Digest()); + mDigest->Begin(SEC_OID_SHA256); + } + + // When we are requested to append to an existing file, we should read the + // existing data and ensure we include it as part of the final hash. + if (mDigest.isSome() && append && !isContinuation) { + nsCOMPtr<nsIInputStream> inputStream; + rv = NS_NewLocalFileInputStream(getter_AddRefs(inputStream), mActualTarget, + PR_RDONLY | nsIFile::OS_READAHEAD); + if (rv != NS_ERROR_FILE_NOT_FOUND) { + NS_ENSURE_SUCCESS(rv, rv); + + // Try to clean up the inputStream if an error occurs. + auto closeGuard = + mozilla::MakeScopeExit([&] { Unused << inputStream->Close(); }); + + char buffer[BUFFERED_IO_SIZE]; + while (true) { + uint32_t count; + rv = inputStream->Read(buffer, BUFFERED_IO_SIZE, &count); + NS_ENSURE_SUCCESS(rv, rv); + + if (count == 0) { + // We reached the end of the file. + break; + } + + rv = mDigest->Update(BitwiseCast<unsigned char*, char*>(buffer), count); + NS_ENSURE_SUCCESS(rv, rv); + + // The pending resume operation may have been cancelled by the control + // thread while the worker thread was reading in the existing file. + // Abort reading in the original file in that case, as the digest will + // be discarded anyway. + MutexAutoLock lock(mLock); + if (NS_FAILED(mStatus)) { + return NS_ERROR_ABORT; + } + } + + // Close explicitly to handle any errors. + closeGuard.release(); + rv = inputStream->Close(); + NS_ENSURE_SUCCESS(rv, rv); + } + } + + // We will append to the initial target file only if it was requested by the + // caller, but we'll always append on subsequent accesses to the target file. + int32_t creationIoFlags; + if (isContinuation) { + creationIoFlags = PR_APPEND; + } else { + creationIoFlags = (append ? PR_APPEND : PR_TRUNCATE) | PR_CREATE_FILE; + } + + // Create the target file, or append to it if we already started writing it. + // The 0600 permissions are used while the file is being downloaded, and for + // interrupted downloads. Those may be located in the system temporary + // directory, as well as the target directory, and generally have a ".part" + // extension. Those part files should never be group or world-writable even + // if the umask allows it. + nsCOMPtr<nsIOutputStream> outputStream; + rv = NS_NewLocalFileOutputStream(getter_AddRefs(outputStream), mActualTarget, + PR_WRONLY | creationIoFlags, 0600); + NS_ENSURE_SUCCESS(rv, rv); + + nsCOMPtr<nsIOutputStream> bufferedStream; + rv = NS_NewBufferedOutputStream(getter_AddRefs(bufferedStream), + outputStream.forget(), BUFFERED_IO_SIZE); + NS_ENSURE_SUCCESS(rv, rv); + outputStream = bufferedStream; + + // Wrap the output stream so that it feeds the digest if needed. + if (mDigest.isSome()) { + // Constructing the DigestOutputStream cannot fail. Passing mDigest + // to DigestOutputStream is safe, because BackgroundFileSaver always + // outlives the outputStream. BackgroundFileSaver is reference-counted + // before the call to AsyncCopy, and mDigest is never destroyed + // before AsyncCopyCallback. + outputStream = new DigestOutputStream(outputStream, mDigest.ref()); + } + + // Start copying our input to the target file. No errors can be raised past + // this point if the copy starts, since they should be handled by the thread. + { + MutexAutoLock lock(mLock); + + rv = NS_AsyncCopy(mPipeInputStream, outputStream, mBackgroundET, + NS_ASYNCCOPY_VIA_READSEGMENTS, 4096, AsyncCopyCallback, + this, false, true, getter_AddRefs(mAsyncCopyContext), + GetProgressCallback()); + if (NS_FAILED(rv)) { + NS_WARNING("NS_AsyncCopy failed."); + mAsyncCopyContext = nullptr; + return rv; + } + } + + // If the operation succeeded, we must ensure that we keep this object alive + // for the entire duration of the copy, since only the raw pointer will be + // provided as the argument of the AsyncCopyCallback function. We can add the + // reference now, after NS_AsyncCopy returned, because it always starts + // processing asynchronously, and there is no risk that the callback is + // invoked before we reach this point. If the operation failed instead, then + // AsyncCopyCallback will never be called. + NS_ADDREF_THIS(); + + return NS_OK; +} + +// Called on the worker thread. +bool BackgroundFileSaver::CheckCompletion() { + nsresult rv; + + bool failed = true; + { + MutexAutoLock lock(mLock); + MOZ_ASSERT(!mAsyncCopyContext, + "Should not be copying when checking completion conditions."); + + if (mComplete) { + return true; + } + + // If an error occurred, we don't need to do the checks in this code block, + // and the operation can be completed immediately with a failure code. + if (NS_SUCCEEDED(mStatus)) { + failed = false; + + // We did not incur in an error, so we must determine if we can stop now. + // If the Finish method has not been called, we can just continue now. + if (!mFinishRequested) { + return false; + } + + // We can only stop when all the operations requested by the control + // thread have been processed. First, we check whether we have processed + // the first SetTarget call, if any. Then, we check whether we have + // processed any rename requested by subsequent SetTarget calls. + if ((mInitialTarget && !mActualTarget) || + (mRenamedTarget && mRenamedTarget != mActualTarget)) { + return false; + } + + // If we still have data to write to the output file, allow the copy + // operation to resume. The Available getter may return an error if one + // of the pipe's streams has been already closed. + uint64_t available; + rv = mPipeInputStream->Available(&available); + if (NS_SUCCEEDED(rv) && available != 0) { + return false; + } + } + + mComplete = true; + } + + // Ensure we notify completion now that the operation finished. + // Do a best-effort attempt to remove the file if required. + if (failed && mActualTarget && !mActualTargetKeepPartial) { + (void)mActualTarget->Remove(false); + } + + // Finish computing the hash + if (!failed && mDigest.isSome()) { + nsTArray<uint8_t> outArray; + rv = mDigest->End(outArray); + if (NS_SUCCEEDED(rv)) { + MutexAutoLock lock(mLock); + mSha256 = nsDependentCSubstring( + BitwiseCast<char*, uint8_t*>(outArray.Elements()), outArray.Length()); + } + } + + // Compute the signature of the binary. ExtractSignatureInfo doesn't do + // anything on non-Windows platforms except return an empty nsIArray. + if (!failed && mActualTarget) { + nsString filePath; + mActualTarget->GetTarget(filePath); + nsresult rv = ExtractSignatureInfo(filePath); + if (NS_FAILED(rv)) { + LOG(("Unable to extract signature information [this = %p].", this)); + } else { + LOG(("Signature extraction success! [this = %p]", this)); + } + } + + // Post an event to notify that the operation completed. + if (NS_FAILED(mControlEventTarget->Dispatch( + NewRunnableMethod("BackgroundFileSaver::NotifySaveComplete", this, + &BackgroundFileSaver::NotifySaveComplete), + NS_DISPATCH_NORMAL))) { + NS_WARNING("Unable to post completion event to the control thread."); + } + + return true; +} + +// Called on the control thread. +nsresult BackgroundFileSaver::NotifyTargetChange(nsIFile* aTarget) { + if (mObserver) { + (void)mObserver->OnTargetChange(this, aTarget); + } + + return NS_OK; +} + +// Called on the control thread. +nsresult BackgroundFileSaver::NotifySaveComplete() { + MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread"); + + nsresult status; + { + MutexAutoLock lock(mLock); + status = mStatus; + } + + if (mObserver) { + (void)mObserver->OnSaveComplete(this, status); + // If mObserver keeps alive an enclosure that captures `this`, we'll have a + // cycle that won't be caught by the cycle-collector, so we need to break it + // when we're done here (see bug 1444265). + mObserver = nullptr; + } + + // At this point, the worker thread will not process any more events, and we + // can shut it down. Shutting down a thread may re-enter the event loop on + // this thread. This is not a problem in this case, since this function is + // called by a top-level event itself, and we have already invoked the + // completion observer callback. Re-entering the loop can only delay the + // final release and destruction of this saver object, since we are keeping a + // reference to it through the event object. + mBackgroundET = nullptr; + + sThreadCount--; + + // When there are no more active downloads, we consider the download session + // finished. We record the maximum number of concurrent downloads reached + // during the session in a telemetry histogram, and we reset the maximum + // thread counter for the next download session + if (sThreadCount == 0) { + Telemetry::Accumulate(Telemetry::BACKGROUNDFILESAVER_THREAD_COUNT, + sTelemetryMaxThreadCount); + sTelemetryMaxThreadCount = 0; + } + + return NS_OK; +} + +nsresult BackgroundFileSaver::ExtractSignatureInfo(const nsAString& filePath) { + MOZ_ASSERT(!NS_IsMainThread(), "Cannot extract signature on main thread"); + { + MutexAutoLock lock(mLock); + if (!mSignatureInfoEnabled) { + return NS_OK; + } + } +#ifdef XP_WIN + // Setup the file to check. + WINTRUST_FILE_INFO fileToCheck = {0}; + fileToCheck.cbStruct = sizeof(WINTRUST_FILE_INFO); + fileToCheck.pcwszFilePath = filePath.Data(); + fileToCheck.hFile = nullptr; + fileToCheck.pgKnownSubject = nullptr; + + // We want to check it is signed and trusted. + WINTRUST_DATA trustData = {0}; + trustData.cbStruct = sizeof(trustData); + trustData.pPolicyCallbackData = nullptr; + trustData.pSIPClientData = nullptr; + trustData.dwUIChoice = WTD_UI_NONE; + trustData.fdwRevocationChecks = WTD_REVOKE_NONE; + trustData.dwUnionChoice = WTD_CHOICE_FILE; + trustData.dwStateAction = WTD_STATEACTION_VERIFY; + trustData.hWVTStateData = nullptr; + trustData.pwszURLReference = nullptr; + // Disallow revocation checks over the network + trustData.dwProvFlags = WTD_CACHE_ONLY_URL_RETRIEVAL; + // no UI + trustData.dwUIContext = 0; + trustData.pFile = &fileToCheck; + + // The WINTRUST_ACTION_GENERIC_VERIFY_V2 policy verifies that the certificate + // chains up to a trusted root CA and has appropriate permissions to sign + // code. + GUID policyGUID = WINTRUST_ACTION_GENERIC_VERIFY_V2; + // Check if the file is signed by something that is trusted. If the file is + // not signed, this is a no-op. + LONG ret = WinVerifyTrust(nullptr, &policyGUID, &trustData); + CRYPT_PROVIDER_DATA* cryptoProviderData = nullptr; + // According to the Windows documentation, we should check against 0 instead + // of ERROR_SUCCESS, which is an HRESULT. + if (ret == 0) { + cryptoProviderData = WTHelperProvDataFromStateData(trustData.hWVTStateData); + } + if (cryptoProviderData) { + // Lock because signature information is read on the main thread. + MutexAutoLock lock(mLock); + LOG(("Downloaded trusted and signed file [this = %p].", this)); + // A binary may have multiple signers. Each signer may have multiple certs + // in the chain. + for (DWORD i = 0; i < cryptoProviderData->csSigners; ++i) { + const CERT_CHAIN_CONTEXT* certChainContext = + cryptoProviderData->pasSigners[i].pChainContext; + if (!certChainContext) { + break; + } + for (DWORD j = 0; j < certChainContext->cChain; ++j) { + const CERT_SIMPLE_CHAIN* certSimpleChain = + certChainContext->rgpChain[j]; + if (!certSimpleChain) { + break; + } + + nsTArray<nsTArray<uint8_t>> certList; + bool extractionSuccess = true; + for (DWORD k = 0; k < certSimpleChain->cElement; ++k) { + CERT_CHAIN_ELEMENT* certChainElement = certSimpleChain->rgpElement[k]; + if (certChainElement->pCertContext->dwCertEncodingType != + X509_ASN_ENCODING) { + continue; + } + nsTArray<uint8_t> cert; + cert.AppendElements(certChainElement->pCertContext->pbCertEncoded, + certChainElement->pCertContext->cbCertEncoded); + certList.AppendElement(std::move(cert)); + } + if (extractionSuccess) { + mSignatureInfo.AppendElement(std::move(certList)); + } + } + } + // Free the provider data if cryptoProviderData is not null. + trustData.dwStateAction = WTD_STATEACTION_CLOSE; + WinVerifyTrust(nullptr, &policyGUID, &trustData); + } else { + LOG(("Downloaded unsigned or untrusted file [this = %p].", this)); + } +#endif + return NS_OK; +} + +//////////////////////////////////////////////////////////////////////////////// +//// BackgroundFileSaverOutputStream + +NS_IMPL_ISUPPORTS(BackgroundFileSaverOutputStream, nsIBackgroundFileSaver, + nsIOutputStream, nsIAsyncOutputStream, + nsIOutputStreamCallback) + +BackgroundFileSaverOutputStream::BackgroundFileSaverOutputStream() + : BackgroundFileSaver(), mAsyncWaitCallback(nullptr) {} + +bool BackgroundFileSaverOutputStream::HasInfiniteBuffer() { return false; } + +nsAsyncCopyProgressFun BackgroundFileSaverOutputStream::GetProgressCallback() { + return nullptr; +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::Close() { return mPipeOutputStream->Close(); } + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::Flush() { return mPipeOutputStream->Flush(); } + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::Write(const char* aBuf, uint32_t aCount, + uint32_t* _retval) { + return mPipeOutputStream->Write(aBuf, aCount, _retval); +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::WriteFrom(nsIInputStream* aFromStream, + uint32_t aCount, uint32_t* _retval) { + return mPipeOutputStream->WriteFrom(aFromStream, aCount, _retval); +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::WriteSegments(nsReadSegmentFun aReader, + void* aClosure, uint32_t aCount, + uint32_t* _retval) { + return mPipeOutputStream->WriteSegments(aReader, aClosure, aCount, _retval); +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::IsNonBlocking(bool* _retval) { + return mPipeOutputStream->IsNonBlocking(_retval); +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::CloseWithStatus(nsresult reason) { + return mPipeOutputStream->CloseWithStatus(reason); +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::AsyncWait(nsIOutputStreamCallback* aCallback, + uint32_t aFlags, + uint32_t aRequestedCount, + nsIEventTarget* aEventTarget) { + NS_ENSURE_STATE(!mAsyncWaitCallback); + + mAsyncWaitCallback = aCallback; + + return mPipeOutputStream->AsyncWait(this, aFlags, aRequestedCount, + aEventTarget); +} + +NS_IMETHODIMP +BackgroundFileSaverOutputStream::OnOutputStreamReady( + nsIAsyncOutputStream* aStream) { + NS_ENSURE_STATE(mAsyncWaitCallback); + + nsCOMPtr<nsIOutputStreamCallback> asyncWaitCallback = nullptr; + asyncWaitCallback.swap(mAsyncWaitCallback); + + return asyncWaitCallback->OnOutputStreamReady(this); +} + +//////////////////////////////////////////////////////////////////////////////// +//// BackgroundFileSaverStreamListener + +NS_IMPL_ISUPPORTS(BackgroundFileSaverStreamListener, nsIBackgroundFileSaver, + nsIRequestObserver, nsIStreamListener) + +bool BackgroundFileSaverStreamListener::HasInfiniteBuffer() { return true; } + +nsAsyncCopyProgressFun +BackgroundFileSaverStreamListener::GetProgressCallback() { + return AsyncCopyProgressCallback; +} + +NS_IMETHODIMP +BackgroundFileSaverStreamListener::OnStartRequest(nsIRequest* aRequest) { + NS_ENSURE_ARG(aRequest); + + return NS_OK; +} + +NS_IMETHODIMP +BackgroundFileSaverStreamListener::OnStopRequest(nsIRequest* aRequest, + nsresult aStatusCode) { + // If an error occurred, cancel the operation immediately. On success, wait + // until the caller has determined whether the file should be renamed. + if (NS_FAILED(aStatusCode)) { + Finish(aStatusCode); + } + + return NS_OK; +} + +NS_IMETHODIMP +BackgroundFileSaverStreamListener::OnDataAvailable(nsIRequest* aRequest, + nsIInputStream* aInputStream, + uint64_t aOffset, + uint32_t aCount) { + nsresult rv; + + NS_ENSURE_ARG(aRequest); + + // Read the requested data. Since the pipe has an infinite buffer, we don't + // expect any write error to occur here. + uint32_t writeCount; + rv = mPipeOutputStream->WriteFrom(aInputStream, aCount, &writeCount); + NS_ENSURE_SUCCESS(rv, rv); + + // If reading from the input stream fails for any reason, the pipe will return + // a success code, but without reading all the data. Since we should be able + // to read the requested data when OnDataAvailable is called, raise an error. + if (writeCount < aCount) { + NS_WARNING("Reading from the input stream should not have failed."); + return NS_ERROR_UNEXPECTED; + } + + bool stateChanged = false; + { + MutexAutoLock lock(mSuspensionLock); + + if (!mReceivedTooMuchData) { + uint64_t available; + nsresult rv = mPipeInputStream->Available(&available); + if (NS_SUCCEEDED(rv) && available > REQUEST_SUSPEND_AT) { + mReceivedTooMuchData = true; + mRequest = aRequest; + stateChanged = true; + } + } + } + + if (stateChanged) { + NotifySuspendOrResume(); + } + + return NS_OK; +} + +// Called on the worker thread. +// static +void BackgroundFileSaverStreamListener::AsyncCopyProgressCallback( + void* aClosure, uint32_t aCount) { + BackgroundFileSaverStreamListener* self = + (BackgroundFileSaverStreamListener*)aClosure; + + // Wait if the control thread is in the process of suspending or resuming. + MutexAutoLock lock(self->mSuspensionLock); + + // This function is called when some bytes are consumed by NS_AsyncCopy. Each + // time this happens, verify if a suspended request should be resumed, because + // we have now consumed enough data. + if (self->mReceivedTooMuchData) { + uint64_t available; + nsresult rv = self->mPipeInputStream->Available(&available); + if (NS_FAILED(rv) || available < REQUEST_RESUME_AT) { + self->mReceivedTooMuchData = false; + + // Post an event to verify if the request should be resumed. + if (NS_FAILED(self->mControlEventTarget->Dispatch( + NewRunnableMethod( + "BackgroundFileSaverStreamListener::NotifySuspendOrResume", + self, + &BackgroundFileSaverStreamListener::NotifySuspendOrResume), + NS_DISPATCH_NORMAL))) { + NS_WARNING("Unable to post resume event to the control thread."); + } + } + } +} + +// Called on the control thread. +nsresult BackgroundFileSaverStreamListener::NotifySuspendOrResume() { + // Prevent the worker thread from changing state while processing. + MutexAutoLock lock(mSuspensionLock); + + if (mReceivedTooMuchData) { + if (!mRequestSuspended) { + // Try to suspend the request. If this fails, don't try to resume later. + if (NS_SUCCEEDED(mRequest->Suspend())) { + mRequestSuspended = true; + } else { + NS_WARNING("Unable to suspend the request."); + } + } + } else { + if (mRequestSuspended) { + // Resume the request only if we succeeded in suspending it. + if (NS_SUCCEEDED(mRequest->Resume())) { + mRequestSuspended = false; + } else { + NS_WARNING("Unable to resume the request."); + } + } + } + + return NS_OK; +} + +//////////////////////////////////////////////////////////////////////////////// +//// DigestOutputStream +NS_IMPL_ISUPPORTS(DigestOutputStream, nsIOutputStream) + +DigestOutputStream::DigestOutputStream(nsIOutputStream* aStream, + Digest& aDigest) + : mOutputStream(aStream), mDigest(aDigest) { + MOZ_ASSERT(mOutputStream, "Can't have null output stream"); +} + +NS_IMETHODIMP +DigestOutputStream::Close() { return mOutputStream->Close(); } + +NS_IMETHODIMP +DigestOutputStream::Flush() { return mOutputStream->Flush(); } + +NS_IMETHODIMP +DigestOutputStream::Write(const char* aBuf, uint32_t aCount, uint32_t* retval) { + nsresult rv = mDigest.Update( + BitwiseCast<const unsigned char*, const char*>(aBuf), aCount); + NS_ENSURE_SUCCESS(rv, rv); + + return mOutputStream->Write(aBuf, aCount, retval); +} + +NS_IMETHODIMP +DigestOutputStream::WriteFrom(nsIInputStream* aFromStream, uint32_t aCount, + uint32_t* retval) { + // Not supported. We could read the stream to a buf, call DigestOp on the + // result, seek back and pass the stream on, but it's not worth it since our + // application (NS_AsyncCopy) doesn't invoke this on the sink. + MOZ_CRASH("DigestOutputStream::WriteFrom not implemented"); +} + +NS_IMETHODIMP +DigestOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure, + uint32_t aCount, uint32_t* retval) { + MOZ_CRASH("DigestOutputStream::WriteSegments not implemented"); +} + +NS_IMETHODIMP +DigestOutputStream::IsNonBlocking(bool* retval) { + return mOutputStream->IsNonBlocking(retval); +} + +#undef LOG_ENABLED + +} // namespace net +} // namespace mozilla |