// // Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023 // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include "td/telegram/files/FileDownloader.h" #include "td/telegram/FileReferenceManager.h" #include "td/telegram/files/FileLoaderUtils.h" #include "td/telegram/files/FileType.h" #include "td/telegram/Global.h" #include "td/telegram/net/DcId.h" #include "td/telegram/SecureStorage.h" #include "td/telegram/telegram_api.h" #include "td/telegram/UniqueId.h" #include "td/utils/as.h" #include "td/utils/base64.h" #include "td/utils/buffer.h" #include "td/utils/common.h" #include "td/utils/crypto.h" #include "td/utils/format.h" #include "td/utils/logging.h" #include "td/utils/misc.h" #include "td/utils/port/path.h" #include "td/utils/port/Stat.h" #include "td/utils/ScopeGuard.h" #include "td/utils/SliceBuilder.h" #include "td/utils/UInt.h" #include <tuple> namespace td { FileDownloader::FileDownloader(const FullRemoteFileLocation &remote, const LocalFileLocation &local, int64 size, string name, const FileEncryptionKey &encryption_key, bool is_small, bool need_search_file, int64 offset, int64 limit, unique_ptr<Callback> callback) : remote_(remote) , local_(local) , size_(size) , name_(std::move(name)) , encryption_key_(encryption_key) , callback_(std::move(callback)) , is_small_(is_small) , need_search_file_(need_search_file) , offset_(offset) , limit_(limit) { if (encryption_key.is_secret()) { set_ordered_flag(true); } if (!encryption_key.empty()) { CHECK(offset_ == 0); } } Result<FileLoader::FileInfo> FileDownloader::init() { SCOPE_EXIT { try_release_fd(); }; if (local_.type() == LocalFileLocation::Type::Full) { return Status::Error("File is already downloaded"); } if (encryption_key_.is_secure() && !encryption_key_.has_value_hash()) { LOG(ERROR) << "Can't download Secure file with unknown value_hash"; } if (remote_.file_type_ == FileType::SecureEncrypted) { size_ = 0; } int32 part_size = 0; Bitmask bitmask{Bitmask::Ones{}, 0}; if (local_.type() == LocalFileLocation::Type::Partial) { const auto &partial = local_.partial(); path_ = partial.path_; auto result_fd = FileFd::open(path_, FileFd::Write | FileFd::Read); // TODO: check timestamps.. if (result_fd.is_ok()) { if ((!encryption_key_.is_secret() || partial.iv_.size() == 32) && partial.part_size_ >= 0 && partial.part_size_ <= (1 << 20) && (partial.part_size_ & (partial.part_size_ - 1)) == 0) { bitmask = Bitmask(Bitmask::Decode{}, partial.ready_bitmask_); if (encryption_key_.is_secret()) { encryption_key_.mutable_iv() = as<UInt256>(partial.iv_.data()); next_part_ = narrow_cast<int32>(bitmask.get_ready_parts(0)); } fd_ = result_fd.move_as_ok(); part_size = static_cast<int32>(partial.part_size_); } else { LOG(ERROR) << "Have invalid " << partial; } } } if (need_search_file_ && fd_.empty() && size_ > 0 && encryption_key_.empty() && !remote_.is_web()) { [&] { TRY_RESULT(path, search_file(remote_.file_type_, name_, size_)); TRY_RESULT(fd, FileFd::open(path, FileFd::Read)); LOG(INFO) << "Check hash of local file " << path; path_ = std::move(path); fd_ = std::move(fd); need_check_ = true; only_check_ = true; part_size = 128 * (1 << 10); bitmask = Bitmask{Bitmask::Ones{}, (size_ + part_size - 1) / part_size}; return Status::OK(); }(); } FileInfo res; res.size = size_; res.is_size_final = true; res.part_size = part_size; res.ready_parts = bitmask.as_vector(); res.use_part_count_limit = false; res.only_check = only_check_; auto file_type = get_main_file_type(remote_.file_type_); res.need_delay = !is_small_ && (file_type == FileType::VideoNote || file_type == FileType::Document || file_type == FileType::VoiceNote || file_type == FileType::Audio || file_type == FileType::Video || file_type == FileType::Animation || file_type == FileType::VideoStory || (file_type == FileType::Encrypted && size_ > (1 << 20))); res.offset = offset_; res.limit = limit_; return res; } Status FileDownloader::on_ok(int64 size) { std::string path; fd_.close(); if (encryption_key_.is_secure()) { TRY_RESULT(file_path, open_temp_file(remote_.file_type_)); string tmp_path; std::tie(std::ignore, tmp_path) = std::move(file_path); TRY_STATUS(secure_storage::decrypt_file(encryption_key_.secret(), encryption_key_.value_hash(), path_, tmp_path)); unlink(path_).ignore(); path_ = std::move(tmp_path); TRY_RESULT(path_stat, stat(path_)); size = path_stat.size_; } if (only_check_) { path = path_; } else { TRY_RESULT_ASSIGN(path, create_from_temp(remote_.file_type_, path_, name_)); } callback_->on_ok(FullLocalFileLocation(remote_.file_type_, std::move(path), 0), size, !only_check_); return Status::OK(); } void FileDownloader::on_error(Status status) { fd_.close(); callback_->on_error(std::move(status)); } Result<bool> FileDownloader::should_restart_part(Part part, NetQueryPtr &net_query) { // Check if we should use CDN or reupload file to CDN if (net_query->is_error()) { if (net_query->error().message() == "FILE_TOKEN_INVALID") { use_cdn_ = false; return true; } if (net_query->error().message() == "REQUEST_TOKEN_INVALID") { return true; } return false; } switch (narrow_cast<QueryType>(UniqueId::extract_key(net_query->id()))) { case QueryType::Default: { if (net_query->ok_tl_constructor() == telegram_api::upload_fileCdnRedirect::ID) { TRY_RESULT(file_base, fetch_result<telegram_api::upload_getFile>(net_query->ok())); CHECK(file_base->get_id() == telegram_api::upload_fileCdnRedirect::ID); auto file = move_tl_object_as<telegram_api::upload_fileCdnRedirect>(file_base); LOG(DEBUG) << "Downloading of part " << part.id << " was redirected to " << oneline(to_string(file)); auto new_cdn_file_token = file->file_token_.as_slice(); if (cdn_file_token_ == new_cdn_file_token) { return true; } use_cdn_ = true; need_check_ = true; cdn_file_token_generation_++; cdn_file_token_ = new_cdn_file_token.str(); cdn_dc_id_ = DcId::external(file->dc_id_); cdn_encryption_key_ = file->encryption_key_.as_slice().str(); cdn_encryption_iv_ = file->encryption_iv_.as_slice().str(); add_hash_info(file->file_hashes_); if (cdn_encryption_iv_.size() != 16 || cdn_encryption_key_.size() != 32) { return Status::Error("Wrong ctr key or iv size"); } return true; } return false; } case QueryType::ReuploadCDN: { TRY_RESULT(file_hashes, fetch_result<telegram_api::upload_reuploadCdnFile>(net_query->ok())); add_hash_info(file_hashes); LOG(DEBUG) << "Part " << part.id << " was reuplaoded to CDN"; return true; } case QueryType::CDN: { if (net_query->ok_tl_constructor() == telegram_api::upload_cdnFileReuploadNeeded::ID) { TRY_RESULT(file_base, fetch_result<telegram_api::upload_getCdnFile>(net_query->ok())); CHECK(file_base->get_id() == telegram_api::upload_cdnFileReuploadNeeded::ID); auto file = move_tl_object_as<telegram_api::upload_cdnFileReuploadNeeded>(file_base); LOG(DEBUG) << "Part " << part.id << " must be reuplaoded to " << oneline(to_string(file)); cdn_part_reupload_token_[part.id] = file->request_token_.as_slice().str(); return true; } auto it = cdn_part_file_token_generation_.find(part.id); CHECK(it != cdn_part_file_token_generation_.end()); if (it->second != cdn_file_token_generation_) { LOG(DEBUG) << "Receive part " << part.id << " with an old file_token"; return true; } return false; } default: UNREACHABLE(); } return false; } Result<std::pair<NetQueryPtr, bool>> FileDownloader::start_part(Part part, int32 part_count, int64 streaming_offset) { if (encryption_key_.is_secret()) { part.size = (part.size + 15) & ~15; // fix for last part } // auto size = part.size; //// sometimes we can ask more than server has, just to check size // if (size < get_part_size()) { // size = min(size + 16, get_part_size()); // LOG(INFO) << "Ask " << size << " instead of " << part.size; //} auto size = get_part_size(); CHECK(part.size <= size); callback_->on_start_download(); auto net_query_type = is_small_ ? NetQuery::Type::DownloadSmall : NetQuery::Type::Download; NetQueryPtr net_query; if (!use_cdn_) { int32 flags = 0; #if !TD_EMSCRIPTEN // CDN is supported, unless we use domains instead of IPs from a browser if (streaming_offset == 0) { flags |= telegram_api::upload_getFile::CDN_SUPPORTED_MASK; } #endif DcId dc_id = remote_.is_web() ? G()->get_webfile_dc_id() : remote_.get_dc_id(); auto unique_id = UniqueId::next(UniqueId::Type::Default, static_cast<uint8>(QueryType::Default)); net_query = remote_.is_web() ? G()->net_query_creator().create( unique_id, telegram_api::upload_getWebFile(remote_.as_input_web_file_location(), narrow_cast<int32>(part.offset), narrow_cast<int32>(size)), {}, dc_id, net_query_type, NetQuery::AuthFlag::On) : G()->net_query_creator().create( unique_id, telegram_api::upload_getFile(flags, false /*ignored*/, false /*ignored*/, remote_.as_input_file_location(), part.offset, narrow_cast<int32>(size)), {}, dc_id, net_query_type, NetQuery::AuthFlag::On); } else { if (remote_.is_web()) { return Status::Error("Can't download web file from CDN"); } auto it = cdn_part_reupload_token_.find(part.id); if (it == cdn_part_reupload_token_.end()) { auto query = telegram_api::upload_getCdnFile(BufferSlice(cdn_file_token_), part.offset, narrow_cast<int32>(size)); cdn_part_file_token_generation_[part.id] = cdn_file_token_generation_; net_query = G()->net_query_creator().create(UniqueId::next(UniqueId::Type::Default, static_cast<uint8>(QueryType::CDN)), query, {}, cdn_dc_id_, net_query_type, NetQuery::AuthFlag::Off); } else { auto query = telegram_api::upload_reuploadCdnFile(BufferSlice(cdn_file_token_), BufferSlice(it->second)); net_query = G()->net_query_creator().create( UniqueId::next(UniqueId::Type::Default, static_cast<uint8>(QueryType::ReuploadCDN)), query, {}, remote_.get_dc_id(), net_query_type, NetQuery::AuthFlag::On); cdn_part_reupload_token_.erase(it); } } net_query->file_type_ = narrow_cast<int32>(remote_.file_type_); return std::make_pair(std::move(net_query), false); } Status FileDownloader::check_net_query(NetQueryPtr &net_query) { if (net_query->is_error()) { auto error = net_query->move_as_error(); if (FileReferenceManager::is_file_reference_error(error)) { VLOG(file_references) << "Receive " << error << " for being downloaded file"; error = Status::Error(error.code(), PSLICE() << error.message() << "#BASE64" << base64_encode(remote_.get_file_reference())); } return error; } return Status::OK(); } Result<size_t> FileDownloader::process_part(Part part, NetQueryPtr net_query) { TRY_STATUS(check_net_query(net_query)); BufferSlice bytes; bool need_cdn_decrypt = false; auto query_type = narrow_cast<QueryType>(UniqueId::extract_key(net_query->id())); switch (query_type) { case QueryType::Default: { if (remote_.is_web()) { TRY_RESULT(file, fetch_result<telegram_api::upload_getWebFile>(net_query->ok())); bytes = std::move(file->bytes_); } else { TRY_RESULT(file_base, fetch_result<telegram_api::upload_getFile>(net_query->ok())); CHECK(file_base->get_id() == telegram_api::upload_file::ID); auto file = move_tl_object_as<telegram_api::upload_file>(file_base); LOG(DEBUG) << "Receive part " << part.id << ": " << to_string(file); bytes = std::move(file->bytes_); } break; } case QueryType::CDN: { TRY_RESULT(file_base, fetch_result<telegram_api::upload_getCdnFile>(net_query->ok())); CHECK(file_base->get_id() == telegram_api::upload_cdnFile::ID); auto file = move_tl_object_as<telegram_api::upload_cdnFile>(file_base); LOG(DEBUG) << "Receive part " << part.id << " from CDN: " << to_string(file); bytes = std::move(file->bytes_); need_cdn_decrypt = true; break; } default: UNREACHABLE(); } auto padded_size = part.size; if (encryption_key_.is_secret()) { padded_size = (part.size + 15) & ~15; } if (bytes.size() > padded_size) { return Status::Error("Part size is more than requested"); } if (bytes.empty()) { return 0; } // Encryption if (need_cdn_decrypt) { CHECK(part.offset % 16 == 0); auto offset = narrow_cast<uint32>(part.offset / 16); offset = ((offset & 0xff) << 24) | ((offset & 0xff00) << 8) | ((offset & 0xff0000) >> 8) | ((offset & 0xff000000) >> 24); AesCtrState ctr_state; string iv = cdn_encryption_iv_; as<uint32>(&iv[12]) = offset; ctr_state.init(cdn_encryption_key_, iv); ctr_state.decrypt(bytes.as_slice(), bytes.as_mutable_slice()); } if (encryption_key_.is_secret()) { LOG_CHECK(next_part_ == part.id) << tag("expected part.id", next_part_) << "!=" << tag("part.id", part.id); CHECK(!next_part_stop_); next_part_++; if (part.size % 16 != 0) { next_part_stop_ = true; } aes_ige_decrypt(as_slice(encryption_key_.key()), as_mutable_slice(encryption_key_.mutable_iv()), bytes.as_slice(), bytes.as_mutable_slice()); } auto slice = bytes.as_slice().substr(0, part.size); TRY_STATUS(acquire_fd()); LOG(INFO) << "Receive " << slice.size() << " bytes at offset " << part.offset << " for \"" << path_ << '"'; TRY_RESULT(written, fd_.pwrite(slice, part.offset)); LOG(INFO) << "Written " << written << " bytes"; // may write less than part.size, when size of downloadable file is unknown if (written != slice.size()) { return Status::Error("Failed to save file part to the file"); } return written; } void FileDownloader::on_progress(Progress progress) { if (progress.is_ready) { // do not send partial location. will lead to wrong local_size return; } if (progress.ready_size == 0 || path_.empty()) { return; } if (encryption_key_.empty() || encryption_key_.is_secure()) { callback_->on_partial_download( PartialLocalFileLocation{remote_.file_type_, progress.part_size, path_, "", std::move(progress.ready_bitmask)}, progress.ready_size, progress.size); } else if (encryption_key_.is_secret()) { UInt256 iv; if (progress.ready_part_count == next_part_) { iv = encryption_key_.mutable_iv(); } else { LOG(FATAL) << tag("ready_part_count", progress.ready_part_count) << tag("next_part", next_part_); } callback_->on_partial_download(PartialLocalFileLocation{remote_.file_type_, progress.part_size, path_, as_slice(iv).str(), std::move(progress.ready_bitmask)}, progress.ready_size, progress.size); } else { UNREACHABLE(); } } FileLoader::Callback *FileDownloader::get_callback() { return static_cast<FileLoader::Callback *>(callback_.get()); } Status FileDownloader::process_check_query(NetQueryPtr net_query) { has_hash_query_ = false; TRY_STATUS(check_net_query(net_query)); TRY_RESULT(file_hashes, fetch_result<telegram_api::upload_getFileHashes>(std::move(net_query))); add_hash_info(file_hashes); return Status::OK(); } Result<FileLoader::CheckInfo> FileDownloader::check_loop(int64 checked_prefix_size, int64 ready_prefix_size, bool is_ready) { if (!need_check_) { return CheckInfo{}; } SCOPE_EXIT { try_release_fd(); }; CheckInfo info; while (checked_prefix_size < ready_prefix_size) { //LOG(ERROR) << "NEED TO CHECK: " << checked_prefix_size << "->" << ready_prefix_size - checked_prefix_size; HashInfo search_info; search_info.offset = checked_prefix_size; auto it = hash_info_.upper_bound(search_info); if (it != hash_info_.begin()) { --it; } if (it != hash_info_.end() && it->offset <= checked_prefix_size && it->offset + narrow_cast<int64>(it->size) > checked_prefix_size) { int64 begin_offset = it->offset; int64 end_offset = it->offset + narrow_cast<int64>(it->size); if (ready_prefix_size < end_offset) { if (!is_ready) { break; } end_offset = ready_prefix_size; } auto size = narrow_cast<size_t>(end_offset - begin_offset); auto slice = BufferSlice(size); TRY_STATUS(acquire_fd()); TRY_RESULT(read_size, fd_.pread(slice.as_mutable_slice(), begin_offset)); if (size != read_size) { return Status::Error("Failed to read file to check hash"); } string hash(32, ' '); sha256(slice.as_slice(), hash); if (hash != it->hash) { if (only_check_) { return Status::Error("FILE_DOWNLOAD_RESTART"); } return Status::Error("Hash mismatch"); } checked_prefix_size = end_offset; info.changed = true; continue; } if (!has_hash_query_) { has_hash_query_ = true; auto query = telegram_api::upload_getFileHashes(remote_.as_input_file_location(), checked_prefix_size); auto net_query_type = is_small_ ? NetQuery::Type::DownloadSmall : NetQuery::Type::Download; auto net_query = G()->net_query_creator().create(query, {}, remote_.get_dc_id(), net_query_type); info.queries.push_back(std::move(net_query)); break; } // Should fail? break; } info.need_check = need_check_; info.checked_prefix_size = checked_prefix_size; return std::move(info); } void FileDownloader::add_hash_info(const std::vector<telegram_api::object_ptr<telegram_api::fileHash>> &hashes) { for (auto &hash : hashes) { //LOG(ERROR) << "ADD HASH " << hash->offset_ << "->" << hash->limit_; HashInfo hash_info; hash_info.size = hash->limit_; hash_info.offset = hash->offset_; hash_info.hash = hash->hash_.as_slice().str(); hash_info_.insert(std::move(hash_info)); } } void FileDownloader::keep_fd_flag(bool keep_fd) { keep_fd_ = keep_fd; try_release_fd(); } void FileDownloader::try_release_fd() { if (!keep_fd_ && !fd_.empty()) { fd_.close(); } } Status FileDownloader::acquire_fd() { if (fd_.empty()) { if (path_.empty()) { TRY_RESULT_ASSIGN(std::tie(fd_, path_), open_temp_file(remote_.file_type_)); } else { TRY_RESULT_ASSIGN(fd_, FileFd::open(path_, (only_check_ ? 0 : FileFd::Write) | FileFd::Read)); } } return Status::OK(); } } // namespace td