/* Copyright (c) 2016, Google Inc. * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include <openssl_grpc/ssl.h> #include <assert.h> #include <limits.h> #include <string.h> #include <utility> #include <openssl_grpc/bytestring.h> #include <openssl_grpc/digest.h> #include <openssl_grpc/err.h> #include <openssl_grpc/mem.h> #include <openssl_grpc/sha.h> #include <openssl_grpc/stack.h> #include "../crypto/internal.h" #include "internal.h" BSSL_NAMESPACE_BEGIN enum client_hs_state_t { state_read_hello_retry_request = 0, state_send_second_client_hello, state_read_server_hello, state_read_encrypted_extensions, state_read_certificate_request, state_read_server_certificate, state_read_server_certificate_verify, state_server_certificate_reverify, state_read_server_finished, state_send_end_of_early_data, state_send_client_encrypted_extensions, state_send_client_certificate, state_send_client_certificate_verify, state_complete_second_flight, state_done, }; static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0}; // end_of_early_data closes the early data stream for |hs| and switches the // encryption level to |level|. It returns true on success and false on error. static bool close_early_data(SSL_HANDSHAKE *hs, ssl_encryption_level_t level) { SSL *const ssl = hs->ssl; assert(hs->in_early_data); // Note |can_early_write| may already be false if |SSL_write| exceeded the // early data write limit. hs->can_early_write = false; // 0-RTT write states on the client differ between TLS 1.3, DTLS 1.3, and // QUIC. TLS 1.3 has one write encryption level at a time. 0-RTT write keys // overwrite the null cipher and defer handshake write keys. While a // HelloRetryRequest can cause us to rewind back to the null cipher, sequence // numbers have no effect, so we can install a "new" null cipher. // // In QUIC and DTLS 1.3, 0-RTT write state cannot override or defer the normal // write state. The two ClientHello sequence numbers must align, and handshake // write keys must be installed early to ACK the EncryptedExtensions. // // We do not currently implement DTLS 1.3 and, in QUIC, the caller handles // 0-RTT data, so we can skip installing 0-RTT keys and act as if there is one // write level. If we implement DTLS 1.3, we'll need to model this better. if (ssl->quic_method == nullptr) { if (level == ssl_encryption_initial) { bssl::UniquePtr<SSLAEADContext> null_ctx = SSLAEADContext::CreateNullCipher(SSL_is_dtls(ssl)); if (!null_ctx || !ssl->method->set_write_state(ssl, ssl_encryption_initial, std::move(null_ctx), /*secret_for_quic=*/{})) { return false; } ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version); } else { assert(level == ssl_encryption_handshake); if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal, hs->new_session.get(), hs->client_handshake_secret())) { return false; } } } assert(ssl->s3->write_level == level); return true; } static bool parse_server_hello_tls13(const SSL_HANDSHAKE *hs, ParsedServerHello *out, uint8_t *out_alert, const SSLMessage &msg) { if (!ssl_parse_server_hello(out, out_alert, msg)) { return false; } // The RFC8446 version of the structure fixes some legacy values. // Additionally, the session ID must echo the original one. if (out->legacy_version != TLS1_2_VERSION || out->compression_method != 0 || !CBS_mem_equal(&out->session_id, hs->session_id, hs->session_id_len) || CBS_len(&out->extensions) == 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); *out_alert = SSL_AD_DECODE_ERROR; return false; } return true; } static bool is_hello_retry_request(const ParsedServerHello &server_hello) { return Span<const uint8_t>(server_hello.random) == kHelloRetryRequest; } static bool check_ech_confirmation(const SSL_HANDSHAKE *hs, bool *out_accepted, uint8_t *out_alert, const ParsedServerHello &server_hello) { const bool is_hrr = is_hello_retry_request(server_hello); size_t offset; if (is_hrr) { // We check for an unsolicited extension when parsing all of them. SSLExtension ech(TLSEXT_TYPE_encrypted_client_hello); if (!ssl_parse_extensions(&server_hello.extensions, out_alert, {&ech}, /*ignore_unknown=*/true)) { return false; } if (!ech.present) { *out_accepted = false; return true; } if (CBS_len(&ech.data) != ECH_CONFIRMATION_SIGNAL_LEN) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); *out_alert = SSL_AD_DECODE_ERROR; return false; } offset = CBS_data(&ech.data) - CBS_data(&server_hello.raw); } else { offset = ssl_ech_confirmation_signal_hello_offset(hs->ssl); } if (!hs->selected_ech_config) { *out_accepted = false; return true; } uint8_t expected[ECH_CONFIRMATION_SIGNAL_LEN]; if (!ssl_ech_accept_confirmation(hs, expected, hs->inner_client_random, hs->inner_transcript, is_hrr, server_hello.raw, offset)) { *out_alert = SSL_AD_INTERNAL_ERROR; return false; } *out_accepted = CRYPTO_memcmp(CBS_data(&server_hello.raw) + offset, expected, sizeof(expected)) == 0; return true; } static enum ssl_hs_wait_t do_read_hello_retry_request(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; assert(ssl->s3->have_version); SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } // Queue up a ChangeCipherSpec for whenever we next send something. This // will be before the second ClientHello. If we offered early data, this was // already done. if (!hs->early_data_offered && !ssl->method->add_change_cipher_spec(ssl)) { return ssl_hs_error; } ParsedServerHello server_hello; uint8_t alert = SSL_AD_DECODE_ERROR; if (!parse_server_hello_tls13(hs, &server_hello, &alert, msg)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } // The cipher suite must be one we offered. We currently offer all supported // TLS 1.3 ciphers, so check the version. const SSL_CIPHER *cipher = SSL_get_cipher_by_value(server_hello.cipher_suite); if (cipher == nullptr || SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) || SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl)) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } hs->new_cipher = cipher; const bool is_hrr = is_hello_retry_request(server_hello); if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) || (is_hrr && !hs->transcript.UpdateForHelloRetryRequest())) { return ssl_hs_error; } if (hs->selected_ech_config) { if (!hs->inner_transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) || (is_hrr && !hs->inner_transcript.UpdateForHelloRetryRequest())) { return ssl_hs_error; } } // Determine which ClientHello the server is responding to. Run // |check_ech_confirmation| unconditionally, so we validate the extension // contents. bool ech_accepted; if (!check_ech_confirmation(hs, &ech_accepted, &alert, server_hello)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (hs->selected_ech_config) { ssl->s3->ech_status = ech_accepted ? ssl_ech_accepted : ssl_ech_rejected; } if (!is_hrr) { hs->tls13_state = state_read_server_hello; return ssl_hs_ok; } // The ECH extension, if present, was already parsed by // |check_ech_confirmation|. SSLExtension cookie(TLSEXT_TYPE_cookie), key_share(TLSEXT_TYPE_key_share), supported_versions(TLSEXT_TYPE_supported_versions), ech_unused(TLSEXT_TYPE_encrypted_client_hello, hs->selected_ech_config || hs->config->ech_grease_enabled); if (!ssl_parse_extensions( &server_hello.extensions, &alert, {&cookie, &key_share, &supported_versions, &ech_unused}, /*ignore_unknown=*/false)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (!cookie.present && !key_share.present) { OPENSSL_PUT_ERROR(SSL, SSL_R_EMPTY_HELLO_RETRY_REQUEST); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } if (cookie.present) { CBS cookie_value; if (!CBS_get_u16_length_prefixed(&cookie.data, &cookie_value) || CBS_len(&cookie_value) == 0 || CBS_len(&cookie.data) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } if (!hs->cookie.CopyFrom(cookie_value)) { return ssl_hs_error; } } if (key_share.present) { uint16_t group_id; if (!CBS_get_u16(&key_share.data, &group_id) || CBS_len(&key_share.data) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } // The group must be supported. if (!tls1_check_group_id(hs, group_id)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); return ssl_hs_error; } // Check that the HelloRetryRequest does not request a key share that was // provided in the initial ClientHello. if (hs->key_shares[0]->GroupID() == group_id || (hs->key_shares[1] && hs->key_shares[1]->GroupID() == group_id)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); return ssl_hs_error; } if (!ssl_setup_key_shares(hs, group_id)) { return ssl_hs_error; } } // Although we now know whether ClientHelloInner was used, we currently // maintain both transcripts up to ServerHello. We could swap transcripts // early, but then ClientHello construction and |check_ech_confirmation| // become more complex. if (!ssl_hash_message(hs, msg)) { return ssl_hs_error; } if (ssl->s3->ech_status == ssl_ech_accepted && !hs->inner_transcript.Update(msg.raw)) { return ssl_hs_error; } // HelloRetryRequest should be the end of the flight. if (ssl->method->has_unprocessed_handshake_data(ssl)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA); return ssl_hs_error; } ssl->method->next_message(ssl); ssl->s3->used_hello_retry_request = true; hs->tls13_state = state_send_second_client_hello; // 0-RTT is rejected if we receive a HelloRetryRequest. if (hs->in_early_data) { ssl->s3->early_data_reason = ssl_early_data_hello_retry_request; if (!close_early_data(hs, ssl_encryption_initial)) { return ssl_hs_error; } return ssl_hs_early_data_rejected; } return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_second_client_hello(SSL_HANDSHAKE *hs) { // Any 0-RTT keys must have been discarded. assert(hs->ssl->s3->write_level == ssl_encryption_initial); // Build the second ClientHelloInner, if applicable. The second ClientHello // uses an empty string for |enc|. if (hs->ssl->s3->ech_status == ssl_ech_accepted && !ssl_encrypt_client_hello(hs, {})) { return ssl_hs_error; } if (!ssl_add_client_hello(hs)) { return ssl_hs_error; } ssl_done_writing_client_hello(hs); hs->tls13_state = state_read_server_hello; return ssl_hs_flush; } static enum ssl_hs_wait_t do_read_server_hello(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } ParsedServerHello server_hello; uint8_t alert = SSL_AD_DECODE_ERROR; if (!parse_server_hello_tls13(hs, &server_hello, &alert, msg)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } // Forbid a second HelloRetryRequest. if (is_hello_retry_request(server_hello)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); return ssl_hs_error; } // Check the cipher suite, in case this is after HelloRetryRequest. if (SSL_CIPHER_get_value(hs->new_cipher) != server_hello.cipher_suite) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } if (ssl->s3->ech_status == ssl_ech_accepted) { if (ssl->s3->used_hello_retry_request) { // HelloRetryRequest and ServerHello must accept ECH consistently. bool ech_accepted; if (!check_ech_confirmation(hs, &ech_accepted, &alert, server_hello)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (!ech_accepted) { OPENSSL_PUT_ERROR(SSL, SSL_R_INCONSISTENT_ECH_NEGOTIATION); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } } hs->transcript = std::move(hs->inner_transcript); hs->extensions.sent = hs->inner_extensions_sent; // Report the inner random value through |SSL_get_client_random|. OPENSSL_memcpy(ssl->s3->client_random, hs->inner_client_random, SSL3_RANDOM_SIZE); } OPENSSL_memcpy(ssl->s3->server_random, CBS_data(&server_hello.random), SSL3_RANDOM_SIZE); // When offering ECH, |ssl->session| is only offered in ClientHelloInner. const bool pre_shared_key_allowed = ssl->session != nullptr && ssl->s3->ech_status != ssl_ech_rejected; SSLExtension key_share(TLSEXT_TYPE_key_share), pre_shared_key(TLSEXT_TYPE_pre_shared_key, pre_shared_key_allowed), supported_versions(TLSEXT_TYPE_supported_versions); if (!ssl_parse_extensions(&server_hello.extensions, &alert, {&key_share, &pre_shared_key, &supported_versions}, /*ignore_unknown=*/false)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } // Recheck supported_versions, in case this is after HelloRetryRequest. uint16_t version; if (!supported_versions.present || !CBS_get_u16(&supported_versions.data, &version) || CBS_len(&supported_versions.data) != 0 || version != ssl->version) { OPENSSL_PUT_ERROR(SSL, SSL_R_SECOND_SERVERHELLO_VERSION_MISMATCH); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } alert = SSL_AD_DECODE_ERROR; if (pre_shared_key.present) { if (!ssl_ext_pre_shared_key_parse_serverhello(hs, &alert, &pre_shared_key.data)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (ssl->session->ssl_version != ssl->version) { OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_VERSION_NOT_RETURNED); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } if (ssl->session->cipher->algorithm_prf != hs->new_cipher->algorithm_prf) { OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_PRF_HASH_MISMATCH); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } if (!ssl_session_is_context_valid(hs, ssl->session.get())) { // This is actually a client application bug. OPENSSL_PUT_ERROR(SSL, SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } ssl->s3->session_reused = true; hs->can_release_private_key = true; // Only authentication information carries over in TLS 1.3. hs->new_session = SSL_SESSION_dup(ssl->session.get(), SSL_SESSION_DUP_AUTH_ONLY); if (!hs->new_session) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } ssl_set_session(ssl, NULL); // Resumption incorporates fresh key material, so refresh the timeout. ssl_session_renew_timeout(ssl, hs->new_session.get(), ssl->session_ctx->session_psk_dhe_timeout); } else if (!ssl_get_new_session(hs)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } hs->new_session->cipher = hs->new_cipher; // Set up the key schedule and incorporate the PSK into the running secret. size_t hash_len = EVP_MD_size( ssl_get_handshake_digest(ssl_protocol_version(ssl), hs->new_cipher)); if (!tls13_init_key_schedule( hs, ssl->s3->session_reused ? MakeConstSpan(hs->new_session->secret, hs->new_session->secret_length) : MakeConstSpan(kZeroes, hash_len))) { return ssl_hs_error; } if (!key_share.present) { // We do not support psk_ke and thus always require a key share. OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION); return ssl_hs_error; } // Resolve ECDHE and incorporate it into the secret. Array<uint8_t> dhe_secret; alert = SSL_AD_DECODE_ERROR; if (!ssl_ext_key_share_parse_serverhello(hs, &dhe_secret, &alert, &key_share.data)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (!tls13_advance_key_schedule(hs, dhe_secret) || !ssl_hash_message(hs, msg) || !tls13_derive_handshake_secrets(hs)) { return ssl_hs_error; } // If currently sending early data over TCP, we defer installing client // traffic keys to when the early data stream is closed. See // |close_early_data|. Note if the server has already rejected 0-RTT via // HelloRetryRequest, |in_early_data| is already false. if (!hs->in_early_data || ssl->quic_method != nullptr) { if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal, hs->new_session.get(), hs->client_handshake_secret())) { return ssl_hs_error; } } if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_open, hs->new_session.get(), hs->server_handshake_secret())) { return ssl_hs_error; } ssl->method->next_message(ssl); hs->tls13_state = state_read_encrypted_extensions; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_encrypted_extensions(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (!ssl_check_message_type(ssl, msg, SSL3_MT_ENCRYPTED_EXTENSIONS)) { return ssl_hs_error; } CBS body = msg.body, extensions; if (!CBS_get_u16_length_prefixed(&body, &extensions) || CBS_len(&body) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } if (!ssl_parse_serverhello_tlsext(hs, &extensions)) { OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); return ssl_hs_error; } if (ssl->s3->early_data_accepted) { // The extension parser checks the server resumed the session. assert(ssl->s3->session_reused); // If offering ECH, the server may not accept early data with // ClientHelloOuter. We do not offer sessions with ClientHelloOuter, so this // this should be implied by checking |session_reused|. assert(ssl->s3->ech_status != ssl_ech_rejected); if (hs->early_session->cipher != hs->new_session->cipher) { OPENSSL_PUT_ERROR(SSL, SSL_R_CIPHER_MISMATCH_ON_EARLY_DATA); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } if (MakeConstSpan(hs->early_session->early_alpn) != ssl->s3->alpn_selected) { OPENSSL_PUT_ERROR(SSL, SSL_R_ALPN_MISMATCH_ON_EARLY_DATA); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } // Channel ID is incompatible with 0-RTT. The ALPS extension should be // negotiated implicitly. if (hs->channel_id_negotiated || hs->new_session->has_application_settings) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION_ON_EARLY_DATA); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } hs->new_session->has_application_settings = hs->early_session->has_application_settings; if (!hs->new_session->local_application_settings.CopyFrom( hs->early_session->local_application_settings) || !hs->new_session->peer_application_settings.CopyFrom( hs->early_session->peer_application_settings)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } } // Store the negotiated ALPN in the session. if (!hs->new_session->early_alpn.CopyFrom(ssl->s3->alpn_selected)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } if (!ssl_hash_message(hs, msg)) { return ssl_hs_error; } ssl->method->next_message(ssl); hs->tls13_state = state_read_certificate_request; if (hs->in_early_data && !ssl->s3->early_data_accepted) { if (!close_early_data(hs, ssl_encryption_handshake)) { return ssl_hs_error; } return ssl_hs_early_data_rejected; } return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; // CertificateRequest may only be sent in non-resumption handshakes. if (ssl->s3->session_reused) { if (ssl->ctx->reverify_on_resume && !ssl->s3->early_data_accepted) { hs->tls13_state = state_server_certificate_reverify; return ssl_hs_ok; } hs->tls13_state = state_read_server_finished; return ssl_hs_ok; } SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } // CertificateRequest is optional. if (msg.type != SSL3_MT_CERTIFICATE_REQUEST) { hs->tls13_state = state_read_server_certificate; return ssl_hs_ok; } SSLExtension sigalgs(TLSEXT_TYPE_signature_algorithms), ca(TLSEXT_TYPE_certificate_authorities); CBS body = msg.body, context, extensions, supported_signature_algorithms; uint8_t alert = SSL_AD_DECODE_ERROR; if (!CBS_get_u8_length_prefixed(&body, &context) || // The request context is always empty during the handshake. CBS_len(&context) != 0 || !CBS_get_u16_length_prefixed(&body, &extensions) || // CBS_len(&body) != 0 || !ssl_parse_extensions(&extensions, &alert, {&sigalgs, &ca}, /*ignore_unknown=*/true) || !sigalgs.present || !CBS_get_u16_length_prefixed(&sigalgs.data, &supported_signature_algorithms) || !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return ssl_hs_error; } if (ca.present) { hs->ca_names = ssl_parse_client_CA_list(ssl, &alert, &ca.data); if (!hs->ca_names) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } } else { hs->ca_names.reset(sk_CRYPTO_BUFFER_new_null()); if (!hs->ca_names) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } } hs->cert_request = true; ssl->ctx->x509_method->hs_flush_cached_ca_names(hs); if (!ssl_hash_message(hs, msg)) { return ssl_hs_error; } ssl->method->next_message(ssl); hs->tls13_state = state_read_server_certificate; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (msg.type != SSL3_MT_COMPRESSED_CERTIFICATE && !ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE)) { return ssl_hs_error; } if (!tls13_process_certificate(hs, msg, false /* certificate required */) || !ssl_hash_message(hs, msg)) { return ssl_hs_error; } ssl->method->next_message(ssl); hs->tls13_state = state_read_server_certificate_verify; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_server_certificate_verify(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } switch (ssl_verify_peer_cert(hs)) { case ssl_verify_ok: break; case ssl_verify_invalid: return ssl_hs_error; case ssl_verify_retry: hs->tls13_state = state_read_server_certificate_verify; return ssl_hs_certificate_verify; } if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY) || !tls13_process_certificate_verify(hs, msg) || !ssl_hash_message(hs, msg)) { return ssl_hs_error; } ssl->method->next_message(ssl); hs->tls13_state = state_read_server_finished; return ssl_hs_ok; } static enum ssl_hs_wait_t do_server_certificate_reverify(SSL_HANDSHAKE *hs) { switch (ssl_reverify_peer_cert(hs, /*send_alert=*/true)) { case ssl_verify_ok: break; case ssl_verify_invalid: return ssl_hs_error; case ssl_verify_retry: hs->tls13_state = state_server_certificate_reverify; return ssl_hs_certificate_verify; } hs->tls13_state = state_read_server_finished; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_server_finished(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (!ssl_check_message_type(ssl, msg, SSL3_MT_FINISHED) || !tls13_process_finished(hs, msg, false /* don't use saved value */) || !ssl_hash_message(hs, msg) || // Update the secret to the master secret and derive traffic keys. !tls13_advance_key_schedule( hs, MakeConstSpan(kZeroes, hs->transcript.DigestLen())) || !tls13_derive_application_secrets(hs)) { return ssl_hs_error; } // Finished should be the end of the flight. if (ssl->method->has_unprocessed_handshake_data(ssl)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA); return ssl_hs_error; } ssl->method->next_message(ssl); hs->tls13_state = state_send_end_of_early_data; return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_end_of_early_data(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (ssl->s3->early_data_accepted) { // QUIC omits the EndOfEarlyData message. See RFC 9001, section 8.3. if (ssl->quic_method == nullptr) { ScopedCBB cbb; CBB body; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_END_OF_EARLY_DATA) || !ssl_add_message_cbb(ssl, cbb.get())) { return ssl_hs_error; } } if (!close_early_data(hs, ssl_encryption_handshake)) { return ssl_hs_error; } } hs->tls13_state = state_send_client_encrypted_extensions; return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_client_encrypted_extensions( SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; // For now, only one extension uses client EncryptedExtensions. This function // may be generalized if others use it in the future. if (hs->new_session->has_application_settings && !ssl->s3->early_data_accepted) { ScopedCBB cbb; CBB body, extensions, extension; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_ENCRYPTED_EXTENSIONS) || !CBB_add_u16_length_prefixed(&body, &extensions) || !CBB_add_u16(&extensions, TLSEXT_TYPE_application_settings) || !CBB_add_u16_length_prefixed(&extensions, &extension) || !CBB_add_bytes(&extension, hs->new_session->local_application_settings.data(), hs->new_session->local_application_settings.size()) || !ssl_add_message_cbb(ssl, cbb.get())) { return ssl_hs_error; } } hs->tls13_state = state_send_client_certificate; return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_client_certificate(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; // The peer didn't request a certificate. if (!hs->cert_request) { hs->tls13_state = state_complete_second_flight; return ssl_hs_ok; } if (ssl->s3->ech_status == ssl_ech_rejected) { // Do not send client certificates on ECH reject. We have not authenticated // the server for the name that can learn the certificate. SSL_certs_clear(ssl); } else if (hs->config->cert->cert_cb != nullptr) { // Call cert_cb to update the certificate. int rv = hs->config->cert->cert_cb(ssl, hs->config->cert->cert_cb_arg); if (rv == 0) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR); return ssl_hs_error; } if (rv < 0) { hs->tls13_state = state_send_client_certificate; return ssl_hs_x509_lookup; } } if (!ssl_on_certificate_selected(hs) || !tls13_add_certificate(hs)) { return ssl_hs_error; } hs->tls13_state = state_send_client_certificate_verify; return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) { // Don't send CertificateVerify if there is no certificate. if (!ssl_has_certificate(hs)) { hs->tls13_state = state_complete_second_flight; return ssl_hs_ok; } switch (tls13_add_certificate_verify(hs)) { case ssl_private_key_success: hs->tls13_state = state_complete_second_flight; return ssl_hs_ok; case ssl_private_key_retry: hs->tls13_state = state_send_client_certificate_verify; return ssl_hs_private_key_operation; case ssl_private_key_failure: return ssl_hs_error; } assert(0); return ssl_hs_error; } static enum ssl_hs_wait_t do_complete_second_flight(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; hs->can_release_private_key = true; // Send a Channel ID assertion if necessary. if (hs->channel_id_negotiated) { ScopedCBB cbb; CBB body; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CHANNEL_ID) || !tls1_write_channel_id(hs, &body) || !ssl_add_message_cbb(ssl, cbb.get())) { return ssl_hs_error; } } // Send a Finished message. if (!tls13_add_finished(hs)) { return ssl_hs_error; } // Derive the final keys and enable them. if (!tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_seal, hs->new_session.get(), hs->client_traffic_secret_0()) || !tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_open, hs->new_session.get(), hs->server_traffic_secret_0()) || !tls13_derive_resumption_secret(hs)) { return ssl_hs_error; } hs->tls13_state = state_done; return ssl_hs_flush; } enum ssl_hs_wait_t tls13_client_handshake(SSL_HANDSHAKE *hs) { while (hs->tls13_state != state_done) { enum ssl_hs_wait_t ret = ssl_hs_error; enum client_hs_state_t state = static_cast<enum client_hs_state_t>(hs->tls13_state); switch (state) { case state_read_hello_retry_request: ret = do_read_hello_retry_request(hs); break; case state_send_second_client_hello: ret = do_send_second_client_hello(hs); break; case state_read_server_hello: ret = do_read_server_hello(hs); break; case state_read_encrypted_extensions: ret = do_read_encrypted_extensions(hs); break; case state_read_certificate_request: ret = do_read_certificate_request(hs); break; case state_read_server_certificate: ret = do_read_server_certificate(hs); break; case state_read_server_certificate_verify: ret = do_read_server_certificate_verify(hs); break; case state_server_certificate_reverify: ret = do_server_certificate_reverify(hs); break; case state_read_server_finished: ret = do_read_server_finished(hs); break; case state_send_end_of_early_data: ret = do_send_end_of_early_data(hs); break; case state_send_client_certificate: ret = do_send_client_certificate(hs); break; case state_send_client_encrypted_extensions: ret = do_send_client_encrypted_extensions(hs); break; case state_send_client_certificate_verify: ret = do_send_client_certificate_verify(hs); break; case state_complete_second_flight: ret = do_complete_second_flight(hs); break; case state_done: ret = ssl_hs_ok; break; } if (hs->tls13_state != state) { ssl_do_info_callback(hs->ssl, SSL_CB_CONNECT_LOOP, 1); } if (ret != ssl_hs_ok) { return ret; } } return ssl_hs_ok; } const char *tls13_client_handshake_state(SSL_HANDSHAKE *hs) { enum client_hs_state_t state = static_cast<enum client_hs_state_t>(hs->tls13_state); switch (state) { case state_read_hello_retry_request: return "TLS 1.3 client read_hello_retry_request"; case state_send_second_client_hello: return "TLS 1.3 client send_second_client_hello"; case state_read_server_hello: return "TLS 1.3 client read_server_hello"; case state_read_encrypted_extensions: return "TLS 1.3 client read_encrypted_extensions"; case state_read_certificate_request: return "TLS 1.3 client read_certificate_request"; case state_read_server_certificate: return "TLS 1.3 client read_server_certificate"; case state_read_server_certificate_verify: return "TLS 1.3 client read_server_certificate_verify"; case state_server_certificate_reverify: return "TLS 1.3 client server_certificate_reverify"; case state_read_server_finished: return "TLS 1.3 client read_server_finished"; case state_send_end_of_early_data: return "TLS 1.3 client send_end_of_early_data"; case state_send_client_encrypted_extensions: return "TLS 1.3 client send_client_encrypted_extensions"; case state_send_client_certificate: return "TLS 1.3 client send_client_certificate"; case state_send_client_certificate_verify: return "TLS 1.3 client send_client_certificate_verify"; case state_complete_second_flight: return "TLS 1.3 client complete_second_flight"; case state_done: return "TLS 1.3 client done"; } return "TLS 1.3 client unknown"; } bool tls13_process_new_session_ticket(SSL *ssl, const SSLMessage &msg) { if (ssl->s3->write_shutdown != ssl_shutdown_none) { // Ignore tickets on shutdown. Callers tend to indiscriminately call // |SSL_shutdown| before destroying an |SSL|, at which point calling the new // session callback may be confusing. return true; } CBS body = msg.body; UniquePtr<SSL_SESSION> session = tls13_create_session_with_ticket(ssl, &body); if (!session) { return false; } if ((ssl->session_ctx->session_cache_mode & SSL_SESS_CACHE_CLIENT) && ssl->session_ctx->new_session_cb != NULL && ssl->session_ctx->new_session_cb(ssl, session.get())) { // |new_session_cb|'s return value signals that it took ownership. session.release(); } return true; } UniquePtr<SSL_SESSION> tls13_create_session_with_ticket(SSL *ssl, CBS *body) { UniquePtr<SSL_SESSION> session = SSL_SESSION_dup( ssl->s3->established_session.get(), SSL_SESSION_INCLUDE_NONAUTH); if (!session) { return nullptr; } ssl_session_rebase_time(ssl, session.get()); uint32_t server_timeout; CBS ticket_nonce, ticket, extensions; if (!CBS_get_u32(body, &server_timeout) || !CBS_get_u32(body, &session->ticket_age_add) || !CBS_get_u8_length_prefixed(body, &ticket_nonce) || !CBS_get_u16_length_prefixed(body, &ticket) || !session->ticket.CopyFrom(ticket) || !CBS_get_u16_length_prefixed(body, &extensions) || CBS_len(body) != 0) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return nullptr; } // Cap the renewable lifetime by the server advertised value. This avoids // wasting bandwidth on 0-RTT when we know the server will reject it. if (session->timeout > server_timeout) { session->timeout = server_timeout; } if (!tls13_derive_session_psk(session.get(), ticket_nonce)) { return nullptr; } SSLExtension early_data(TLSEXT_TYPE_early_data); uint8_t alert = SSL_AD_DECODE_ERROR; if (!ssl_parse_extensions(&extensions, &alert, {&early_data}, /*ignore_unknown=*/true)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return nullptr; } if (early_data.present) { if (!CBS_get_u32(&early_data.data, &session->ticket_max_early_data) || CBS_len(&early_data.data) != 0) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return nullptr; } // QUIC does not use the max_early_data_size parameter and always sets it to // a fixed value. See RFC 9001, section 4.6.1. if (ssl->quic_method != nullptr && session->ticket_max_early_data != 0xffffffff) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return nullptr; } } // Historically, OpenSSL filled in fake session IDs for ticket-based sessions. // Envoy's tests depend on this, although perhaps they shouldn't. SHA256(CBS_data(&ticket), CBS_len(&ticket), session->session_id); session->session_id_length = SHA256_DIGEST_LENGTH; session->ticket_age_add_valid = true; session->not_resumable = false; return session; } BSSL_NAMESPACE_END