| // Copyright (c) 2020 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "quiche/quic/core/tls_chlo_extractor.h" |
| |
| #include <cstdint> |
| #include <cstring> |
| #include <memory> |
| #include <ostream> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/strings/str_cat.h" |
| #include "absl/strings/string_view.h" |
| #include "openssl/ssl.h" |
| #include "quiche/quic/core/frames/quic_crypto_frame.h" |
| #include "quiche/quic/core/quic_data_reader.h" |
| #include "quiche/quic/core/quic_error_codes.h" |
| #include "quiche/quic/core/quic_framer.h" |
| #include "quiche/quic/core/quic_time.h" |
| #include "quiche/quic/core/quic_types.h" |
| #include "quiche/quic/core/quic_versions.h" |
| #include "quiche/quic/platform/api/quic_bug_tracker.h" |
| #include "quiche/quic/platform/api/quic_flags.h" |
| #include "quiche/common/platform/api/quiche_logging.h" |
| |
| namespace quic { |
| |
| namespace { |
| bool HasExtension(const SSL_CLIENT_HELLO* client_hello, uint16_t extension) { |
| const uint8_t* unused_extension_bytes; |
| size_t unused_extension_len; |
| return 1 == SSL_early_callback_ctx_extension_get(client_hello, extension, |
| &unused_extension_bytes, |
| &unused_extension_len); |
| } |
| |
| std::vector<uint16_t> GetSupportedGroups(const SSL_CLIENT_HELLO* client_hello) { |
| const uint8_t* extension_data; |
| size_t extension_len; |
| int rv = SSL_early_callback_ctx_extension_get( |
| client_hello, TLSEXT_TYPE_supported_groups, &extension_data, |
| &extension_len); |
| if (rv != 1) { |
| return {}; |
| } |
| |
| // See https://datatracker.ietf.org/doc/html/rfc8446#section-4.2.7 for the |
| // format of this extension. |
| QuicDataReader named_groups_reader( |
| reinterpret_cast<const char*>(extension_data), extension_len); |
| uint16_t named_groups_len; |
| if (!named_groups_reader.ReadUInt16(&named_groups_len) || |
| named_groups_len + sizeof(uint16_t) != extension_len) { |
| QUIC_CODE_COUNT(quic_chlo_supported_groups_invalid_length); |
| return {}; |
| } |
| |
| std::vector<uint16_t> named_groups; |
| while (!named_groups_reader.IsDoneReading()) { |
| uint16_t named_group; |
| if (!named_groups_reader.ReadUInt16(&named_group)) { |
| QUIC_CODE_COUNT(quic_chlo_supported_groups_odd_length); |
| QUIC_LOG_FIRST_N(WARNING, 10) << "Failed to read named groups"; |
| break; |
| } |
| named_groups.push_back(named_group); |
| } |
| return named_groups; |
| } |
| |
| } // namespace |
| |
| TlsChloExtractor::TlsChloExtractor() |
| : crypto_stream_sequencer_(this), |
| state_(State::kInitial), |
| parsed_crypto_frame_in_this_packet_(false) {} |
| |
| TlsChloExtractor::TlsChloExtractor(TlsChloExtractor&& other) |
| : TlsChloExtractor() { |
| *this = std::move(other); |
| } |
| |
| TlsChloExtractor& TlsChloExtractor::operator=(TlsChloExtractor&& other) { |
| framer_ = std::move(other.framer_); |
| if (framer_) { |
| framer_->set_visitor(this); |
| } |
| crypto_stream_sequencer_ = std::move(other.crypto_stream_sequencer_); |
| crypto_stream_sequencer_.set_stream(this); |
| ssl_ = std::move(other.ssl_); |
| if (ssl_) { |
| std::pair<SSL_CTX*, int> shared_handles = GetSharedSslHandles(); |
| int ex_data_index = shared_handles.second; |
| const int rv = SSL_set_ex_data(ssl_.get(), ex_data_index, this); |
| QUICHE_CHECK_EQ(rv, 1) << "Internal allocation failure in SSL_set_ex_data"; |
| } |
| state_ = other.state_; |
| error_details_ = std::move(other.error_details_); |
| parsed_crypto_frame_in_this_packet_ = |
| other.parsed_crypto_frame_in_this_packet_; |
| supported_groups_ = std::move(other.supported_groups_); |
| alpns_ = std::move(other.alpns_); |
| server_name_ = std::move(other.server_name_); |
| client_hello_bytes_ = std::move(other.client_hello_bytes_); |
| return *this; |
| } |
| |
| void TlsChloExtractor::IngestPacket(const ParsedQuicVersion& version, |
| const QuicReceivedPacket& packet) { |
| if (state_ == State::kUnrecoverableFailure) { |
| QUIC_DLOG(ERROR) << "Not ingesting packet after unrecoverable error"; |
| return; |
| } |
| if (version == UnsupportedQuicVersion()) { |
| QUIC_DLOG(ERROR) << "Not ingesting packet with unsupported version"; |
| return; |
| } |
| if (version.handshake_protocol != PROTOCOL_TLS1_3) { |
| QUIC_DLOG(ERROR) << "Not ingesting packet with non-TLS version " << version; |
| return; |
| } |
| if (framer_) { |
| // This is not the first packet we have ingested, check if version matches. |
| if (!framer_->IsSupportedVersion(version)) { |
| QUIC_DLOG(ERROR) |
| << "Not ingesting packet with version mismatch, expected " |
| << framer_->version() << ", got " << version; |
| return; |
| } |
| } else { |
| // This is the first packet we have ingested, setup parser. |
| framer_ = std::make_unique<QuicFramer>( |
| ParsedQuicVersionVector{version}, QuicTime::Zero(), |
| Perspective::IS_SERVER, /*expected_server_connection_id_length=*/0); |
| // Note that expected_server_connection_id_length only matters for short |
| // headers and we explicitly drop those so we can pass any value here. |
| framer_->set_visitor(this); |
| } |
| |
| // When the framer parses |packet|, if it sees a CRYPTO frame it will call |
| // OnCryptoFrame below and that will set parsed_crypto_frame_in_this_packet_ |
| // to true. |
| parsed_crypto_frame_in_this_packet_ = false; |
| const bool parse_success = framer_->ProcessPacket(packet); |
| if (state_ == State::kInitial && parsed_crypto_frame_in_this_packet_) { |
| // If we parsed a CRYPTO frame but didn't advance the state from initial, |
| // then it means that we will need more packets to reassemble the full CHLO, |
| // so we advance the state here. This can happen when the first packet |
| // received is not the first one in the crypto stream. This allows us to |
| // differentiate our state between single-packet CHLO and multi-packet CHLO. |
| state_ = State::kParsedPartialChloFragment; |
| } |
| |
| if (!parse_success) { |
| // This could be due to the packet being non-initial for example. |
| QUIC_DLOG(ERROR) << "Failed to process packet"; |
| return; |
| } |
| } |
| |
| // This is called when the framer parsed the unencrypted parts of the header. |
| bool TlsChloExtractor::OnUnauthenticatedPublicHeader( |
| const QuicPacketHeader& header) { |
| if (header.form != IETF_QUIC_LONG_HEADER_PACKET) { |
| QUIC_DLOG(ERROR) << "Not parsing non-long-header packet " << header; |
| return false; |
| } |
| if (header.long_packet_type != INITIAL) { |
| QUIC_DLOG(ERROR) << "Not parsing non-initial packet " << header; |
| return false; |
| } |
| // QuicFramer is constructed without knowledge of the server's connection ID |
| // so it needs to be set up here in order to decrypt the packet. |
| framer_->SetInitialObfuscators(header.destination_connection_id); |
| return true; |
| } |
| |
| // This is called by the framer if it detects a change in version during |
| // parsing. |
| bool TlsChloExtractor::OnProtocolVersionMismatch(ParsedQuicVersion version) { |
| // This should never be called because we already check versions in |
| // IngestPacket. |
| QUIC_BUG(quic_bug_10855_1) << "Unexpected version mismatch, expected " |
| << framer_->version() << ", got " << version; |
| return false; |
| } |
| |
| // This is called by the QuicStreamSequencer if it encounters an unrecoverable |
| // error that will prevent it from reassembling the crypto stream data. |
| void TlsChloExtractor::OnUnrecoverableError(QuicErrorCode error, |
| const std::string& details) { |
| HandleUnrecoverableError(absl::StrCat( |
| "Crypto stream error ", QuicErrorCodeToString(error), ": ", details)); |
| } |
| |
| void TlsChloExtractor::OnUnrecoverableError( |
| QuicErrorCode error, QuicIetfTransportErrorCodes ietf_error, |
| const std::string& details) { |
| HandleUnrecoverableError(absl::StrCat( |
| "Crypto stream error ", QuicErrorCodeToString(error), "(", |
| QuicIetfTransportErrorCodeString(ietf_error), "): ", details)); |
| } |
| |
| // This is called by the framer if it sees a CRYPTO frame during parsing. |
| bool TlsChloExtractor::OnCryptoFrame(const QuicCryptoFrame& frame) { |
| if (frame.level != ENCRYPTION_INITIAL) { |
| // Since we drop non-INITIAL packets in OnUnauthenticatedPublicHeader, |
| // we should never receive any CRYPTO frames at other encryption levels. |
| QUIC_BUG(quic_bug_10855_2) << "Parsed bad-level CRYPTO frame " << frame; |
| return false; |
| } |
| // parsed_crypto_frame_in_this_packet_ is checked in IngestPacket to allow |
| // advancing our state to track the difference between single-packet CHLO |
| // and multi-packet CHLO. |
| parsed_crypto_frame_in_this_packet_ = true; |
| crypto_stream_sequencer_.OnCryptoFrame(frame); |
| return true; |
| } |
| |
| // Called by the QuicStreamSequencer when it receives a CRYPTO frame that |
| // advances the amount of contiguous data we now have starting from offset 0. |
| void TlsChloExtractor::OnDataAvailable() { |
| // Lazily set up BoringSSL handle. |
| SetupSslHandle(); |
| |
| // Get data from the stream sequencer and pass it to BoringSSL. |
| struct iovec iov; |
| while (crypto_stream_sequencer_.GetReadableRegion(&iov)) { |
| const int rv = SSL_provide_quic_data( |
| ssl_.get(), ssl_encryption_initial, |
| reinterpret_cast<const uint8_t*>(iov.iov_base), iov.iov_len); |
| if (rv != 1) { |
| HandleUnrecoverableError("SSL_provide_quic_data failed"); |
| return; |
| } |
| crypto_stream_sequencer_.MarkConsumed(iov.iov_len); |
| } |
| |
| // Instruct BoringSSL to attempt parsing a full CHLO from the provided data. |
| // We ignore the return value since we know the handshake is going to fail |
| // because we explicitly cancel processing once we've parsed the CHLO. |
| (void)SSL_do_handshake(ssl_.get()); |
| } |
| |
| // static |
| TlsChloExtractor* TlsChloExtractor::GetInstanceFromSSL(SSL* ssl) { |
| std::pair<SSL_CTX*, int> shared_handles = GetSharedSslHandles(); |
| int ex_data_index = shared_handles.second; |
| return reinterpret_cast<TlsChloExtractor*>( |
| SSL_get_ex_data(ssl, ex_data_index)); |
| } |
| |
| // static |
| int TlsChloExtractor::SetReadSecretCallback( |
| SSL* ssl, enum ssl_encryption_level_t /*level*/, |
| const SSL_CIPHER* /*cipher*/, const uint8_t* /*secret*/, |
| size_t /*secret_length*/) { |
| GetInstanceFromSSL(ssl)->HandleUnexpectedCallback("SetReadSecretCallback"); |
| return 0; |
| } |
| |
| // static |
| int TlsChloExtractor::SetWriteSecretCallback( |
| SSL* ssl, enum ssl_encryption_level_t /*level*/, |
| const SSL_CIPHER* /*cipher*/, const uint8_t* /*secret*/, |
| size_t /*secret_length*/) { |
| GetInstanceFromSSL(ssl)->HandleUnexpectedCallback("SetWriteSecretCallback"); |
| return 0; |
| } |
| |
| // static |
| int TlsChloExtractor::WriteMessageCallback( |
| SSL* ssl, enum ssl_encryption_level_t /*level*/, const uint8_t* /*data*/, |
| size_t /*len*/) { |
| GetInstanceFromSSL(ssl)->HandleUnexpectedCallback("WriteMessageCallback"); |
| return 0; |
| } |
| |
| // static |
| int TlsChloExtractor::FlushFlightCallback(SSL* ssl) { |
| GetInstanceFromSSL(ssl)->HandleUnexpectedCallback("FlushFlightCallback"); |
| return 0; |
| } |
| |
| void TlsChloExtractor::HandleUnexpectedCallback( |
| const std::string& callback_name) { |
| std::string error_details = |
| absl::StrCat("Unexpected callback ", callback_name); |
| QUIC_BUG(quic_bug_10855_3) << error_details; |
| HandleUnrecoverableError(error_details); |
| } |
| |
| // static |
| int TlsChloExtractor::SendAlertCallback(SSL* ssl, |
| enum ssl_encryption_level_t /*level*/, |
| uint8_t desc) { |
| GetInstanceFromSSL(ssl)->SendAlert(desc); |
| return 0; |
| } |
| |
| void TlsChloExtractor::SendAlert(uint8_t tls_alert_value) { |
| if (tls_alert_value == SSL3_AD_HANDSHAKE_FAILURE && HasParsedFullChlo()) { |
| // This is the most common scenario. Since we return an error from |
| // SelectCertCallback in order to cancel further processing, BoringSSL will |
| // try to send this alert to tell the client that the handshake failed. |
| return; |
| } |
| HandleUnrecoverableError(absl::StrCat( |
| "BoringSSL attempted to send alert ", static_cast<int>(tls_alert_value), |
| " ", SSL_alert_desc_string_long(tls_alert_value))); |
| if (state_ == State::kUnrecoverableFailure) { |
| tls_alert_ = tls_alert_value; |
| } |
| } |
| |
| // static |
| enum ssl_select_cert_result_t TlsChloExtractor::SelectCertCallback( |
| const SSL_CLIENT_HELLO* client_hello) { |
| GetInstanceFromSSL(client_hello->ssl)->HandleParsedChlo(client_hello); |
| // Always return an error to cancel any further processing in BoringSSL. |
| return ssl_select_cert_error; |
| } |
| |
| // Extracts the server name and ALPN from the parsed ClientHello. |
| void TlsChloExtractor::HandleParsedChlo(const SSL_CLIENT_HELLO* client_hello) { |
| const char* server_name = |
| SSL_get_servername(client_hello->ssl, TLSEXT_NAMETYPE_host_name); |
| if (server_name) { |
| server_name_ = std::string(server_name); |
| } |
| |
| resumption_attempted_ = |
| HasExtension(client_hello, TLSEXT_TYPE_pre_shared_key); |
| early_data_attempted_ = HasExtension(client_hello, TLSEXT_TYPE_early_data); |
| |
| QUICHE_DCHECK(client_hello_bytes_.empty()); |
| client_hello_bytes_.assign( |
| client_hello->client_hello, |
| client_hello->client_hello + client_hello->client_hello_len); |
| |
| const uint8_t* alpn_data; |
| size_t alpn_len; |
| int rv = SSL_early_callback_ctx_extension_get( |
| client_hello, TLSEXT_TYPE_application_layer_protocol_negotiation, |
| &alpn_data, &alpn_len); |
| if (rv == 1) { |
| QuicDataReader alpns_reader(reinterpret_cast<const char*>(alpn_data), |
| alpn_len); |
| absl::string_view alpns_payload; |
| if (!alpns_reader.ReadStringPiece16(&alpns_payload)) { |
| HandleUnrecoverableError("Failed to read alpns_payload"); |
| return; |
| } |
| QuicDataReader alpns_payload_reader(alpns_payload); |
| while (!alpns_payload_reader.IsDoneReading()) { |
| absl::string_view alpn_payload; |
| if (!alpns_payload_reader.ReadStringPiece8(&alpn_payload)) { |
| HandleUnrecoverableError("Failed to read alpn_payload"); |
| return; |
| } |
| alpns_.emplace_back(std::string(alpn_payload)); |
| } |
| } |
| |
| supported_groups_ = GetSupportedGroups(client_hello); |
| |
| // Update our state now that we've parsed a full CHLO. |
| if (state_ == State::kInitial) { |
| state_ = State::kParsedFullSinglePacketChlo; |
| } else if (state_ == State::kParsedPartialChloFragment) { |
| state_ = State::kParsedFullMultiPacketChlo; |
| } else { |
| QUIC_BUG(quic_bug_10855_4) |
| << "Unexpected state on successful parse " << StateToString(state_); |
| } |
| } |
| |
| // static |
| std::pair<SSL_CTX*, int> TlsChloExtractor::GetSharedSslHandles() { |
| // Use a lambda to benefit from C++11 guarantee that static variables are |
| // initialized lazily in a thread-safe manner. |shared_handles| is therefore |
| // guaranteed to be initialized exactly once and never destructed. |
| static std::pair<SSL_CTX*, int>* shared_handles = []() { |
| CRYPTO_library_init(); |
| SSL_CTX* ssl_ctx = SSL_CTX_new(TLS_with_buffers_method()); |
| SSL_CTX_set_min_proto_version(ssl_ctx, TLS1_3_VERSION); |
| SSL_CTX_set_max_proto_version(ssl_ctx, TLS1_3_VERSION); |
| static const SSL_QUIC_METHOD kQuicCallbacks{ |
| TlsChloExtractor::SetReadSecretCallback, |
| TlsChloExtractor::SetWriteSecretCallback, |
| TlsChloExtractor::WriteMessageCallback, |
| TlsChloExtractor::FlushFlightCallback, |
| TlsChloExtractor::SendAlertCallback}; |
| SSL_CTX_set_quic_method(ssl_ctx, &kQuicCallbacks); |
| SSL_CTX_set_select_certificate_cb(ssl_ctx, |
| TlsChloExtractor::SelectCertCallback); |
| int ex_data_index = |
| SSL_get_ex_new_index(0, nullptr, nullptr, nullptr, nullptr); |
| return new std::pair<SSL_CTX*, int>(ssl_ctx, ex_data_index); |
| }(); |
| return *shared_handles; |
| } |
| |
| // Sets up the per-instance SSL handle needed by BoringSSL. |
| void TlsChloExtractor::SetupSslHandle() { |
| if (ssl_) { |
| // Handles have already been set up. |
| return; |
| } |
| |
| std::pair<SSL_CTX*, int> shared_handles = GetSharedSslHandles(); |
| SSL_CTX* ssl_ctx = shared_handles.first; |
| int ex_data_index = shared_handles.second; |
| |
| ssl_ = bssl::UniquePtr<SSL>(SSL_new(ssl_ctx)); |
| const int rv = SSL_set_ex_data(ssl_.get(), ex_data_index, this); |
| QUICHE_CHECK_EQ(rv, 1) << "Internal allocation failure in SSL_set_ex_data"; |
| SSL_set_accept_state(ssl_.get()); |
| |
| // Make sure we use the right TLS extension codepoint. |
| int use_legacy_extension = 0; |
| if (framer_->version().UsesLegacyTlsExtension()) { |
| use_legacy_extension = 1; |
| } |
| SSL_set_quic_use_legacy_codepoint(ssl_.get(), use_legacy_extension); |
| } |
| |
| // Called by other methods to record any unrecoverable failures they experience. |
| void TlsChloExtractor::HandleUnrecoverableError( |
| const std::string& error_details) { |
| if (HasParsedFullChlo()) { |
| // Ignore errors if we've parsed everything successfully. |
| QUIC_DLOG(ERROR) << "Ignoring error: " << error_details; |
| return; |
| } |
| QUIC_DLOG(ERROR) << "Handling error: " << error_details; |
| |
| state_ = State::kUnrecoverableFailure; |
| |
| if (error_details_.empty()) { |
| error_details_ = error_details; |
| } else { |
| error_details_ = absl::StrCat(error_details_, "; ", error_details); |
| } |
| } |
| |
| // static |
| std::string TlsChloExtractor::StateToString(State state) { |
| switch (state) { |
| case State::kInitial: |
| return "Initial"; |
| case State::kParsedFullSinglePacketChlo: |
| return "ParsedFullSinglePacketChlo"; |
| case State::kParsedFullMultiPacketChlo: |
| return "ParsedFullMultiPacketChlo"; |
| case State::kParsedPartialChloFragment: |
| return "ParsedPartialChloFragment"; |
| case State::kUnrecoverableFailure: |
| return "UnrecoverableFailure"; |
| } |
| return absl::StrCat("Unknown(", static_cast<int>(state), ")"); |
| } |
| |
| std::ostream& operator<<(std::ostream& os, |
| const TlsChloExtractor::State& state) { |
| os << TlsChloExtractor::StateToString(state); |
| return os; |
| } |
| |
| } // namespace quic |