/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ /* ==================================================================== * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * openssl-core@openssl.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.openssl.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ /* ==================================================================== * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. * * Portions of the attached software ("Contribution") are developed by * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project. * * The Contribution is licensed pursuant to the OpenSSL open source * license provided above. * * ECC cipher suite support in OpenSSL originally written by * Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories. * */ /* ==================================================================== * Copyright 2005 Nokia. All rights reserved. * * The portions of the attached software ("Contribution") is developed by * Nokia Corporation and is licensed pursuant to the OpenSSL open source * license. * * The Contribution, originally written by Mika Kousa and Pasi Eronen of * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites * support (see RFC 4279) to OpenSSL. * * No patent licenses or other rights except those expressly stated in * the OpenSSL open source license shall be deemed granted or received * expressly, by implication, estoppel, or otherwise. * * No assurances are provided by Nokia that the Contribution does not * infringe the patent or other intellectual property rights of any third * party or that the license provides you with all the necessary rights * to make use of the Contribution. * * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR * OTHERWISE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "../crypto/internal.h" #include "internal.h" BSSL_NAMESPACE_BEGIN enum ssl_client_hs_state_t { state_start_connect = 0, state_enter_early_data, state_early_reverify_server_certificate, state_read_hello_verify_request, state_read_server_hello, state_tls13, state_read_server_certificate, state_read_certificate_status, state_verify_server_certificate, state_reverify_server_certificate, state_read_server_key_exchange, state_read_certificate_request, state_read_server_hello_done, state_send_client_certificate, state_send_client_key_exchange, state_send_client_certificate_verify, state_send_client_finished, state_finish_flight, state_read_session_ticket, state_process_change_cipher_spec, state_read_server_finished, state_finish_client_handshake, state_done, }; // ssl_get_client_disabled sets |*out_mask_a| and |*out_mask_k| to masks of // disabled algorithms. static void ssl_get_client_disabled(const SSL_HANDSHAKE *hs, uint32_t *out_mask_a, uint32_t *out_mask_k) { *out_mask_a = 0; *out_mask_k = 0; // PSK requires a client callback. if (hs->config->psk_client_callback == NULL) { *out_mask_a |= SSL_aPSK; *out_mask_k |= SSL_kPSK; } } static bool ssl_write_client_cipher_list(const SSL_HANDSHAKE *hs, CBB *out, ssl_client_hello_type_t type) { const SSL *const ssl = hs->ssl; uint32_t mask_a, mask_k; ssl_get_client_disabled(hs, &mask_a, &mask_k); CBB child; if (!CBB_add_u16_length_prefixed(out, &child)) { return false; } // Add a fake cipher suite. See RFC 8701. if (ssl->ctx->grease_enabled && !CBB_add_u16(&child, ssl_get_grease_value(hs, ssl_grease_cipher))) { return false; } // Add TLS 1.3 ciphers. Order ChaCha20-Poly1305 relative to AES-GCM based on // hardware support. if (hs->max_version >= TLS1_3_VERSION) { if (!EVP_has_aes_hardware() && !CBB_add_u16(&child, TLS1_CK_CHACHA20_POLY1305_SHA256 & 0xffff)) { return false; } if (!CBB_add_u16(&child, TLS1_CK_AES_128_GCM_SHA256 & 0xffff) || !CBB_add_u16(&child, TLS1_CK_AES_256_GCM_SHA384 & 0xffff)) { return false; } if (EVP_has_aes_hardware() && !CBB_add_u16(&child, TLS1_CK_CHACHA20_POLY1305_SHA256 & 0xffff)) { return false; } } if (hs->min_version < TLS1_3_VERSION && type != ssl_client_hello_inner) { bool any_enabled = false; for (const SSL_CIPHER *cipher : SSL_get_ciphers(ssl)) { // Skip disabled ciphers if ((cipher->algorithm_mkey & mask_k) || (cipher->algorithm_auth & mask_a)) { continue; } if (SSL_CIPHER_get_min_version(cipher) > hs->max_version || SSL_CIPHER_get_max_version(cipher) < hs->min_version) { continue; } any_enabled = true; if (!CBB_add_u16(&child, SSL_CIPHER_get_protocol_id(cipher))) { return false; } } // If all ciphers were disabled, return the error to the caller. if (!any_enabled && hs->max_version < TLS1_3_VERSION) { OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CIPHERS_AVAILABLE); return false; } } if (ssl->mode & SSL_MODE_SEND_FALLBACK_SCSV) { if (!CBB_add_u16(&child, SSL3_CK_FALLBACK_SCSV & 0xffff)) { return false; } } return CBB_flush(out); } bool ssl_write_client_hello_without_extensions(const SSL_HANDSHAKE *hs, CBB *cbb, ssl_client_hello_type_t type, bool empty_session_id) { const SSL *const ssl = hs->ssl; CBB child; if (!CBB_add_u16(cbb, hs->client_version) || !CBB_add_bytes(cbb, type == ssl_client_hello_inner ? hs->inner_client_random : ssl->s3->client_random, SSL3_RANDOM_SIZE) || !CBB_add_u8_length_prefixed(cbb, &child)) { return false; } // Do not send a session ID on renegotiation. if (!ssl->s3->initial_handshake_complete && !empty_session_id && !CBB_add_bytes(&child, hs->session_id, hs->session_id_len)) { return false; } if (SSL_is_dtls(ssl)) { if (!CBB_add_u8_length_prefixed(cbb, &child) || !CBB_add_bytes(&child, ssl->d1->cookie, ssl->d1->cookie_len)) { return false; } } if (!ssl_write_client_cipher_list(hs, cbb, type) || !CBB_add_u8(cbb, 1 /* one compression method */) || !CBB_add_u8(cbb, 0 /* null compression */)) { return false; } return true; } bool ssl_add_client_hello(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; ScopedCBB cbb; CBB body; ssl_client_hello_type_t type = hs->selected_ech_config ? ssl_client_hello_outer : ssl_client_hello_unencrypted; bool needs_psk_binder; Array msg; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CLIENT_HELLO) || !ssl_write_client_hello_without_extensions(hs, &body, type, /*empty_session_id*/ false) || !ssl_add_clienthello_tlsext(hs, &body, /*out_encoded=*/nullptr, &needs_psk_binder, type, CBB_len(&body)) || !ssl->method->finish_message(ssl, cbb.get(), &msg)) { return false; } // Now that the length prefixes have been computed, fill in the placeholder // PSK binder. if (needs_psk_binder) { // ClientHelloOuter cannot have a PSK binder. Otherwise the // ClientHellOuterAAD computation would break. assert(type != ssl_client_hello_outer); if (!tls13_write_psk_binder(hs, hs->transcript, MakeSpan(msg), /*out_binder_len=*/0)) { return false; } } return ssl->method->add_message(ssl, std::move(msg)); } static bool parse_server_version(const SSL_HANDSHAKE *hs, uint16_t *out_version, uint8_t *out_alert, const ParsedServerHello &server_hello) { // If the outer version is not TLS 1.2, use it. // TODO(davidben): This function doesn't quite match the RFC8446 formulation. if (server_hello.legacy_version != TLS1_2_VERSION) { *out_version = server_hello.legacy_version; return true; } SSLExtension supported_versions(TLSEXT_TYPE_supported_versions); CBS extensions = server_hello.extensions; if (!ssl_parse_extensions(&extensions, out_alert, {&supported_versions}, /*ignore_unknown=*/true)) { return false; } if (!supported_versions.present) { *out_version = server_hello.legacy_version; return true; } if (!CBS_get_u16(&supported_versions.data, out_version) || CBS_len(&supported_versions.data) != 0) { *out_alert = SSL_AD_DECODE_ERROR; return false; } return true; } // should_offer_early_data returns |ssl_early_data_accepted| if |hs| should // offer early data, and some other reason code otherwise. static ssl_early_data_reason_t should_offer_early_data( const SSL_HANDSHAKE *hs) { const SSL *const ssl = hs->ssl; assert(!ssl->server); if (!ssl->enable_early_data) { return ssl_early_data_disabled; } if (hs->max_version < TLS1_3_VERSION) { // We discard inapplicable sessions, so this is redundant with the session // checks below, but reporting that TLS 1.3 was disabled is more useful. return ssl_early_data_protocol_version; } if (ssl->session == nullptr) { return ssl_early_data_no_session_offered; } if (ssl_session_protocol_version(ssl->session.get()) < TLS1_3_VERSION || ssl->session->ticket_max_early_data == 0) { return ssl_early_data_unsupported_for_session; } if (!ssl->session->early_alpn.empty()) { if (!ssl_is_alpn_protocol_allowed(hs, ssl->session->early_alpn)) { // Avoid reporting a confusing value in |SSL_get0_alpn_selected|. return ssl_early_data_alpn_mismatch; } // If the previous connection negotiated ALPS, only offer 0-RTT when the // local are settings are consistent with what we'd offer for this // connection. if (ssl->session->has_application_settings) { Span settings; if (!ssl_get_local_application_settings(hs, &settings, ssl->session->early_alpn) || settings != ssl->session->local_application_settings) { return ssl_early_data_alps_mismatch; } } } // Early data has not yet been accepted, but we use it as a success code. return ssl_early_data_accepted; } void ssl_done_writing_client_hello(SSL_HANDSHAKE *hs) { hs->ech_client_outer.Reset(); hs->cookie.Reset(); hs->key_share_bytes.Reset(); } static enum ssl_hs_wait_t do_start_connect(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_START, 1); // |session_reused| must be reset in case this is a renegotiation. ssl->s3->session_reused = false; // Freeze the version range. if (!ssl_get_version_range(hs, &hs->min_version, &hs->max_version)) { return ssl_hs_error; } uint8_t ech_enc[EVP_HPKE_MAX_ENC_LENGTH]; size_t ech_enc_len; if (!ssl_select_ech_config(hs, ech_enc, &ech_enc_len)) { return ssl_hs_error; } // Always advertise the ClientHello version from the original maximum version, // even on renegotiation. The static RSA key exchange uses this field, and // some servers fail when it changes across handshakes. if (SSL_is_dtls(hs->ssl)) { hs->client_version = hs->max_version >= TLS1_2_VERSION ? DTLS1_2_VERSION : DTLS1_VERSION; } else { hs->client_version = hs->max_version >= TLS1_2_VERSION ? TLS1_2_VERSION : hs->max_version; } // If the configured session has expired or is not usable, drop it. We also do // not offer sessions on renegotiation. if (ssl->session != nullptr) { if (ssl->session->is_server || !ssl_supports_version(hs, ssl->session->ssl_version) || // Do not offer TLS 1.2 sessions with ECH. ClientHelloInner does not // offer TLS 1.2, and the cleartext session ID may leak the server // identity. (hs->selected_ech_config && ssl_session_protocol_version(ssl->session.get()) < TLS1_3_VERSION) || !SSL_SESSION_is_resumable(ssl->session.get()) || !ssl_session_is_time_valid(ssl, ssl->session.get()) || (ssl->quic_method != nullptr) != ssl->session->is_quic || ssl->s3->initial_handshake_complete) { ssl_set_session(ssl, nullptr); } } if (!RAND_bytes(ssl->s3->client_random, sizeof(ssl->s3->client_random))) { return ssl_hs_error; } if (hs->selected_ech_config && !RAND_bytes(hs->inner_client_random, sizeof(hs->inner_client_random))) { return ssl_hs_error; } // Never send a session ID in QUIC. QUIC uses TLS 1.3 at a minimum and // disables TLS 1.3 middlebox compatibility mode. if (ssl->quic_method == nullptr) { const bool has_id_session = ssl->session != nullptr && ssl->session->session_id_length > 0 && ssl->session->ticket.empty(); const bool has_ticket_session = ssl->session != nullptr && !ssl->session->ticket.empty(); if (has_id_session) { hs->session_id_len = ssl->session->session_id_length; OPENSSL_memcpy(hs->session_id, ssl->session->session_id, hs->session_id_len); } else if (has_ticket_session || hs->max_version >= TLS1_3_VERSION) { // Send a random session ID. TLS 1.3 always sends one, and TLS 1.2 session // tickets require a placeholder value to signal resumption. hs->session_id_len = sizeof(hs->session_id); if (!RAND_bytes(hs->session_id, hs->session_id_len)) { return ssl_hs_error; } } } ssl_early_data_reason_t reason = should_offer_early_data(hs); if (reason != ssl_early_data_accepted) { ssl->s3->early_data_reason = reason; } else { hs->early_data_offered = true; } if (!ssl_setup_key_shares(hs, /*override_group_id=*/0) || !ssl_setup_extension_permutation(hs) || !ssl_encrypt_client_hello(hs, MakeConstSpan(ech_enc, ech_enc_len)) || !ssl_add_client_hello(hs)) { return ssl_hs_error; } hs->state = state_enter_early_data; return ssl_hs_flush; } static enum ssl_hs_wait_t do_enter_early_data(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (SSL_is_dtls(ssl)) { hs->state = state_read_hello_verify_request; return ssl_hs_ok; } if (!hs->early_data_offered) { hs->state = state_read_server_hello; return ssl_hs_ok; } ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->session->ssl_version); if (!ssl->method->add_change_cipher_spec(ssl)) { return ssl_hs_error; } if (!tls13_init_early_key_schedule(hs, ssl->session.get()) || !tls13_derive_early_secret(hs)) { return ssl_hs_error; } // Stash the early data session, so connection properties may be queried out // of it. hs->early_session = UpRef(ssl->session); hs->state = state_early_reverify_server_certificate; return ssl_hs_ok; } static enum ssl_hs_wait_t do_early_reverify_server_certificate(SSL_HANDSHAKE *hs) { if (hs->ssl->ctx->reverify_on_resume) { // Don't send an alert on error. The alert be in early data, which the // server may not accept anyway. It would also be a mismatch between QUIC // and TCP because the QUIC early keys are deferred below. // // TODO(davidben): The client behavior should be to verify the certificate // before deciding whether to offer the session and, if invalid, decline to // send the session. switch (ssl_reverify_peer_cert(hs, /*send_alert=*/false)) { case ssl_verify_ok: break; case ssl_verify_invalid: return ssl_hs_error; case ssl_verify_retry: hs->state = state_early_reverify_server_certificate; return ssl_hs_certificate_verify; } } // Defer releasing the 0-RTT key to after certificate reverification, so the // QUIC implementation does not accidentally write data too early. if (!tls13_set_traffic_key(hs->ssl, ssl_encryption_early_data, evp_aead_seal, hs->early_session.get(), hs->early_traffic_secret())) { return ssl_hs_error; } hs->in_early_data = true; hs->can_early_write = true; hs->state = state_read_server_hello; return ssl_hs_early_return; } static enum ssl_hs_wait_t do_read_hello_verify_request(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; assert(SSL_is_dtls(ssl)); // When implementing DTLS 1.3, we need to handle the interactions between // HelloVerifyRequest, DTLS 1.3's HelloVerifyRequest removal, and ECH. assert(hs->max_version < TLS1_3_VERSION); SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (msg.type != DTLS1_MT_HELLO_VERIFY_REQUEST) { hs->state = state_read_server_hello; return ssl_hs_ok; } CBS hello_verify_request = msg.body, cookie; uint16_t server_version; if (!CBS_get_u16(&hello_verify_request, &server_version) || !CBS_get_u8_length_prefixed(&hello_verify_request, &cookie) || CBS_len(&cookie) > sizeof(ssl->d1->cookie) || CBS_len(&hello_verify_request) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } OPENSSL_memcpy(ssl->d1->cookie, CBS_data(&cookie), CBS_len(&cookie)); ssl->d1->cookie_len = CBS_len(&cookie); ssl->method->next_message(ssl); // DTLS resets the handshake buffer after HelloVerifyRequest. if (!hs->transcript.Init()) { return ssl_hs_error; } if (!ssl_add_client_hello(hs)) { return ssl_hs_error; } hs->state = state_read_server_hello; return ssl_hs_flush; } bool ssl_parse_server_hello(ParsedServerHello *out, uint8_t *out_alert, const SSLMessage &msg) { if (msg.type != SSL3_MT_SERVER_HELLO) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return false; } out->raw = msg.raw; CBS body = msg.body; if (!CBS_get_u16(&body, &out->legacy_version) || !CBS_get_bytes(&body, &out->random, SSL3_RANDOM_SIZE) || !CBS_get_u8_length_prefixed(&body, &out->session_id) || CBS_len(&out->session_id) > SSL3_SESSION_ID_SIZE || !CBS_get_u16(&body, &out->cipher_suite) || !CBS_get_u8(&body, &out->compression_method)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); *out_alert = SSL_AD_DECODE_ERROR; return false; } // In TLS 1.2 and below, empty extensions blocks may be omitted. In TLS 1.3, // ServerHellos always have extensions, so this can be applied generically. CBS_init(&out->extensions, nullptr, 0); if ((CBS_len(&body) != 0 && !CBS_get_u16_length_prefixed(&body, &out->extensions)) || CBS_len(&body) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); *out_alert = SSL_AD_DECODE_ERROR; return false; } return true; } 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_server_hello; } ParsedServerHello server_hello; uint16_t server_version; uint8_t alert = SSL_AD_DECODE_ERROR; if (!ssl_parse_server_hello(&server_hello, &alert, msg) || !parse_server_version(hs, &server_version, &alert, server_hello)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (!ssl_supports_version(hs, server_version)) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION); return ssl_hs_error; } assert(ssl->s3->have_version == ssl->s3->initial_handshake_complete); if (!ssl->s3->have_version) { ssl->version = server_version; // At this point, the connection's version is known and ssl->version is // fixed. Begin enforcing the record-layer version. ssl->s3->have_version = true; ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version); } else if (server_version != ssl->version) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SSL_VERSION); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION); return ssl_hs_error; } if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) { hs->state = state_tls13; return ssl_hs_ok; } // Clear some TLS 1.3 state that no longer needs to be retained. hs->key_shares[0].reset(); hs->key_shares[1].reset(); ssl_done_writing_client_hello(hs); // A TLS 1.2 server would not know to skip the early data we offered. Report // an error code sooner. The caller may use this error code to implement the // fallback described in RFC 8446 appendix D.3. if (hs->early_data_offered) { // Disconnect early writes. This ensures subsequent |SSL_write| calls query // the handshake which, in turn, will replay the error code rather than fail // at the |write_shutdown| check. See https://crbug.com/1078515. // TODO(davidben): Should all handshake errors do this? What about record // decryption failures? hs->can_early_write = false; OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_ON_EARLY_DATA); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION); return ssl_hs_error; } // TLS 1.2 handshakes cannot accept ECH. if (hs->selected_ech_config) { ssl->s3->ech_status = ssl_ech_rejected; } // Copy over the server random. OPENSSL_memcpy(ssl->s3->server_random, CBS_data(&server_hello.random), SSL3_RANDOM_SIZE); // Enforce the TLS 1.3 anti-downgrade feature. if (!ssl->s3->initial_handshake_complete && ssl_supports_version(hs, TLS1_3_VERSION)) { static_assert( sizeof(kTLS12DowngradeRandom) == sizeof(kTLS13DowngradeRandom), "downgrade signals have different size"); static_assert( sizeof(kJDK11DowngradeRandom) == sizeof(kTLS13DowngradeRandom), "downgrade signals have different size"); auto suffix = MakeConstSpan(ssl->s3->server_random, sizeof(ssl->s3->server_random)) .subspan(SSL3_RANDOM_SIZE - sizeof(kTLS13DowngradeRandom)); if (suffix == kTLS12DowngradeRandom || suffix == kTLS13DowngradeRandom || suffix == kJDK11DowngradeRandom) { OPENSSL_PUT_ERROR(SSL, SSL_R_TLS13_DOWNGRADE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } } // The cipher must be allowed in the selected version and enabled. const SSL_CIPHER *cipher = SSL_get_cipher_by_value(server_hello.cipher_suite); uint32_t mask_a, mask_k; ssl_get_client_disabled(hs, &mask_a, &mask_k); if (cipher == nullptr || (cipher->algorithm_mkey & mask_k) || (cipher->algorithm_auth & mask_a) || SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) || SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl) || !sk_SSL_CIPHER_find(SSL_get_ciphers(ssl), nullptr, cipher)) { 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; if (hs->session_id_len != 0 && CBS_mem_equal(&server_hello.session_id, hs->session_id, hs->session_id_len)) { // Echoing the ClientHello session ID in TLS 1.2, whether from the session // or a synthetic one, indicates resumption. If there was no session (or if // the session was only offered in ECH ClientHelloInner), this was the // TLS 1.3 compatibility mode session ID. As we know this is not a session // the server knows about, any server resuming it is in error. Reject the // first connection deterministicly, rather than installing an invalid // session into the session cache. https://crbug.com/796910 if (ssl->session == nullptr || ssl->s3->ech_status == ssl_ech_rejected) { OPENSSL_PUT_ERROR(SSL, SSL_R_SERVER_ECHOED_INVALID_SESSION_ID); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); 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 != hs->new_cipher) { OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED); 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; } // We never offer sessions on renegotiation. assert(!ssl->s3->initial_handshake_complete); ssl->s3->session_reused = true; } else { // The session wasn't resumed. Create a fresh SSL_SESSION to fill out. ssl_set_session(ssl, NULL); if (!ssl_get_new_session(hs)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } // Note: session_id could be empty. hs->new_session->session_id_length = CBS_len(&server_hello.session_id); OPENSSL_memcpy(hs->new_session->session_id, CBS_data(&server_hello.session_id), CBS_len(&server_hello.session_id)); hs->new_session->cipher = hs->new_cipher; } // Now that the cipher is known, initialize the handshake hash and hash the // ServerHello. if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) || !ssl_hash_message(hs, msg)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } // If doing a full handshake, the server may request a client certificate // which requires hashing the handshake transcript. Otherwise, the handshake // buffer may be released. if (ssl->session != NULL || !ssl_cipher_uses_certificate_auth(hs->new_cipher)) { hs->transcript.FreeBuffer(); } // Only the NULL compression algorithm is supported. if (server_hello.compression_method != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } if (!ssl_parse_serverhello_tlsext(hs, &server_hello.extensions)) { OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); return ssl_hs_error; } if (ssl->session != NULL && hs->extended_master_secret != ssl->session->extended_master_secret) { if (ssl->session->extended_master_secret) { OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION); } else { OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_NON_EMS_SESSION_WITH_EMS_EXTENSION); } ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); return ssl_hs_error; } ssl->method->next_message(ssl); if (ssl->session != NULL) { if (ssl->ctx->reverify_on_resume && ssl_cipher_uses_certificate_auth(hs->new_cipher)) { hs->state = state_reverify_server_certificate; } else { hs->state = state_read_session_ticket; } return ssl_hs_ok; } hs->state = state_read_server_certificate; return ssl_hs_ok; } static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) { enum ssl_hs_wait_t wait = tls13_client_handshake(hs); if (wait == ssl_hs_ok) { hs->state = state_finish_client_handshake; return ssl_hs_ok; } return wait; } static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) { hs->state = state_read_certificate_status; return ssl_hs_ok; } SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE) || !ssl_hash_message(hs, msg)) { return ssl_hs_error; } CBS body = msg.body; uint8_t alert = SSL_AD_DECODE_ERROR; if (!ssl_parse_cert_chain(&alert, &hs->new_session->certs, &hs->peer_pubkey, NULL, &body, ssl->ctx->pool)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (sk_CRYPTO_BUFFER_num(hs->new_session->certs.get()) == 0 || CBS_len(&body) != 0 || !ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) { 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_check_leaf_certificate( hs, hs->peer_pubkey.get(), sk_CRYPTO_BUFFER_value(hs->new_session->certs.get(), 0))) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } ssl->method->next_message(ssl); hs->state = state_read_certificate_status; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_certificate_status(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (!hs->certificate_status_expected) { hs->state = state_verify_server_certificate; return ssl_hs_ok; } SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (msg.type != SSL3_MT_CERTIFICATE_STATUS) { // A server may send status_request in ServerHello and then change its mind // about sending CertificateStatus. hs->state = state_verify_server_certificate; return ssl_hs_ok; } if (!ssl_hash_message(hs, msg)) { return ssl_hs_error; } CBS certificate_status = msg.body, ocsp_response; uint8_t status_type; if (!CBS_get_u8(&certificate_status, &status_type) || status_type != TLSEXT_STATUSTYPE_ocsp || !CBS_get_u24_length_prefixed(&certificate_status, &ocsp_response) || CBS_len(&ocsp_response) == 0 || CBS_len(&certificate_status) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } hs->new_session->ocsp_response.reset( CRYPTO_BUFFER_new_from_CBS(&ocsp_response, ssl->ctx->pool)); if (hs->new_session->ocsp_response == nullptr) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } ssl->method->next_message(ssl); hs->state = state_verify_server_certificate; return ssl_hs_ok; } static enum ssl_hs_wait_t do_verify_server_certificate(SSL_HANDSHAKE *hs) { if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) { hs->state = state_read_server_key_exchange; return ssl_hs_ok; } switch (ssl_verify_peer_cert(hs)) { case ssl_verify_ok: break; case ssl_verify_invalid: return ssl_hs_error; case ssl_verify_retry: hs->state = state_verify_server_certificate; return ssl_hs_certificate_verify; } hs->state = state_read_server_key_exchange; return ssl_hs_ok; } static enum ssl_hs_wait_t do_reverify_server_certificate(SSL_HANDSHAKE *hs) { assert(hs->ssl->ctx->reverify_on_resume); 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->state = state_reverify_server_certificate; return ssl_hs_certificate_verify; } hs->state = state_read_session_ticket; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_server_key_exchange(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_SERVER_KEY_EXCHANGE) { // Some ciphers (pure PSK) have an optional ServerKeyExchange message. if (ssl_cipher_requires_server_key_exchange(hs->new_cipher)) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); return ssl_hs_error; } hs->state = state_read_certificate_request; return ssl_hs_ok; } if (!ssl_hash_message(hs, msg)) { return ssl_hs_error; } uint32_t alg_k = hs->new_cipher->algorithm_mkey; uint32_t alg_a = hs->new_cipher->algorithm_auth; CBS server_key_exchange = msg.body; if (alg_a & SSL_aPSK) { CBS psk_identity_hint; // Each of the PSK key exchanges begins with a psk_identity_hint. if (!CBS_get_u16_length_prefixed(&server_key_exchange, &psk_identity_hint)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } // Store the PSK identity hint for the ClientKeyExchange. Assume that the // maximum length of a PSK identity hint can be as long as the maximum // length of a PSK identity. Also do not allow NULL characters; identities // are saved as C strings. // // TODO(davidben): Should invalid hints be ignored? It's a hint rather than // a specific identity. if (CBS_len(&psk_identity_hint) > PSK_MAX_IDENTITY_LEN || CBS_contains_zero_byte(&psk_identity_hint)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); return ssl_hs_error; } // Save non-empty identity hints as a C string. Empty identity hints we // treat as missing. Plain PSK makes it possible to send either no hint // (omit ServerKeyExchange) or an empty hint, while ECDHE_PSK can only spell // empty hint. Having different capabilities is odd, so we interpret empty // and missing as identical. char *raw = nullptr; if (CBS_len(&psk_identity_hint) != 0 && !CBS_strdup(&psk_identity_hint, &raw)) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } hs->peer_psk_identity_hint.reset(raw); } if (alg_k & SSL_kECDHE) { // Parse the server parameters. uint8_t group_type; uint16_t group_id; CBS point; if (!CBS_get_u8(&server_key_exchange, &group_type) || group_type != NAMED_CURVE_TYPE || !CBS_get_u16(&server_key_exchange, &group_id) || !CBS_get_u8_length_prefixed(&server_key_exchange, &point)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } hs->new_session->group_id = group_id; // Ensure the group is consistent with preferences. if (!tls1_check_group_id(hs, group_id)) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return ssl_hs_error; } // Initialize ECDH and save the peer public key for later. hs->key_shares[0] = SSLKeyShare::Create(group_id); if (!hs->key_shares[0] || !hs->peer_key.CopyFrom(point)) { return ssl_hs_error; } } else if (!(alg_k & SSL_kPSK)) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); return ssl_hs_error; } // At this point, |server_key_exchange| contains the signature, if any, while // |msg.body| contains the entire message. From that, derive a CBS containing // just the parameter. CBS parameter; CBS_init(¶meter, CBS_data(&msg.body), CBS_len(&msg.body) - CBS_len(&server_key_exchange)); // ServerKeyExchange should be signed by the server's public key. if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) { uint16_t signature_algorithm = 0; if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) { if (!CBS_get_u16(&server_key_exchange, &signature_algorithm)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } uint8_t alert = SSL_AD_DECODE_ERROR; if (!tls12_check_peer_sigalg(hs, &alert, signature_algorithm)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } hs->new_session->peer_signature_algorithm = signature_algorithm; } else if (!tls1_get_legacy_signature_algorithm(&signature_algorithm, hs->peer_pubkey.get())) { OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE); return ssl_hs_error; } // The last field in |server_key_exchange| is the signature. CBS signature; if (!CBS_get_u16_length_prefixed(&server_key_exchange, &signature) || CBS_len(&server_key_exchange) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } ScopedCBB transcript; Array transcript_data; if (!CBB_init(transcript.get(), 2 * SSL3_RANDOM_SIZE + CBS_len(¶meter)) || !CBB_add_bytes(transcript.get(), ssl->s3->client_random, SSL3_RANDOM_SIZE) || !CBB_add_bytes(transcript.get(), ssl->s3->server_random, SSL3_RANDOM_SIZE) || !CBB_add_bytes(transcript.get(), CBS_data(¶meter), CBS_len(¶meter)) || !CBBFinishArray(transcript.get(), &transcript_data)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } if (!ssl_public_key_verify(ssl, signature, signature_algorithm, hs->peer_pubkey.get(), transcript_data)) { // bad signature OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); return ssl_hs_error; } } else { // PSK ciphers are the only supported certificate-less ciphers. assert(alg_a == SSL_aPSK); if (CBS_len(&server_key_exchange) > 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_EXTRA_DATA_IN_MESSAGE); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return ssl_hs_error; } } ssl->method->next_message(ssl); hs->state = state_read_certificate_request; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) { hs->state = state_read_server_hello_done; return ssl_hs_ok; } SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (msg.type == SSL3_MT_SERVER_HELLO_DONE) { // If we get here we don't need the handshake buffer as we won't be doing // client auth. hs->transcript.FreeBuffer(); hs->state = state_read_server_hello_done; return ssl_hs_ok; } if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_REQUEST) || !ssl_hash_message(hs, msg)) { return ssl_hs_error; } // Get the certificate types. CBS body = msg.body, certificate_types; if (!CBS_get_u8_length_prefixed(&body, &certificate_types)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return ssl_hs_error; } if (!hs->certificate_types.CopyFrom(certificate_types)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); return ssl_hs_error; } if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) { CBS supported_signature_algorithms; if (!CBS_get_u16_length_prefixed(&body, &supported_signature_algorithms) || !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return ssl_hs_error; } } uint8_t alert = SSL_AD_DECODE_ERROR; UniquePtr ca_names = ssl_parse_client_CA_list(ssl, &alert, &body); if (!ca_names) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (CBS_len(&body) != 0) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return ssl_hs_error; } hs->cert_request = true; hs->ca_names = std::move(ca_names); ssl->ctx->x509_method->hs_flush_cached_ca_names(hs); ssl->method->next_message(ssl); hs->state = state_read_server_hello_done; return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_server_hello_done(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_SERVER_HELLO_DONE) || !ssl_hash_message(hs, msg)) { return ssl_hs_error; } // ServerHelloDone is empty. if (CBS_len(&msg.body) != 0) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return ssl_hs_error; } // ServerHelloDone 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->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->state = state_send_client_key_exchange; 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->state = state_send_client_certificate; return ssl_hs_x509_lookup; } } if (!ssl_has_certificate(hs)) { // Without a client certificate, the handshake buffer may be released. hs->transcript.FreeBuffer(); } if (!ssl_on_certificate_selected(hs) || !ssl_output_cert_chain(hs)) { return ssl_hs_error; } hs->state = state_send_client_key_exchange; return ssl_hs_ok; } static_assert(sizeof(size_t) >= sizeof(unsigned), "size_t is smaller than unsigned"); static enum ssl_hs_wait_t do_send_client_key_exchange(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; ScopedCBB cbb; CBB body; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CLIENT_KEY_EXCHANGE)) { return ssl_hs_error; } Array pms; uint32_t alg_k = hs->new_cipher->algorithm_mkey; uint32_t alg_a = hs->new_cipher->algorithm_auth; if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) { const CRYPTO_BUFFER *leaf = sk_CRYPTO_BUFFER_value(hs->new_session->certs.get(), 0); CBS leaf_cbs; CRYPTO_BUFFER_init_CBS(leaf, &leaf_cbs); // Check the key usage matches the cipher suite. We do this unconditionally // for non-RSA certificates. In particular, it's needed to distinguish ECDH // certificates, which we do not support, from ECDSA certificates. // Historically, we have not checked RSA key usages, so it is controlled by // a flag for now. See https://crbug.com/795089. ssl_key_usage_t intended_use = (alg_k & SSL_kRSA) ? key_usage_encipherment : key_usage_digital_signature; if (hs->config->enforce_rsa_key_usage || EVP_PKEY_id(hs->peer_pubkey.get()) != EVP_PKEY_RSA) { if (!ssl_cert_check_key_usage(&leaf_cbs, intended_use)) { return ssl_hs_error; } } } // If using a PSK key exchange, prepare the pre-shared key. unsigned psk_len = 0; uint8_t psk[PSK_MAX_PSK_LEN]; if (alg_a & SSL_aPSK) { if (hs->config->psk_client_callback == NULL) { OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_NO_CLIENT_CB); return ssl_hs_error; } char identity[PSK_MAX_IDENTITY_LEN + 1]; OPENSSL_memset(identity, 0, sizeof(identity)); psk_len = hs->config->psk_client_callback( ssl, hs->peer_psk_identity_hint.get(), identity, sizeof(identity), psk, sizeof(psk)); if (psk_len == 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND); ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); return ssl_hs_error; } assert(psk_len <= PSK_MAX_PSK_LEN); hs->new_session->psk_identity.reset(OPENSSL_strdup(identity)); if (hs->new_session->psk_identity == nullptr) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return ssl_hs_error; } // Write out psk_identity. CBB child; if (!CBB_add_u16_length_prefixed(&body, &child) || !CBB_add_bytes(&child, (const uint8_t *)identity, OPENSSL_strnlen(identity, sizeof(identity))) || !CBB_flush(&body)) { return ssl_hs_error; } } // Depending on the key exchange method, compute |pms|. if (alg_k & SSL_kRSA) { if (!pms.Init(SSL_MAX_MASTER_KEY_LENGTH)) { return ssl_hs_error; } RSA *rsa = EVP_PKEY_get0_RSA(hs->peer_pubkey.get()); if (rsa == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return ssl_hs_error; } pms[0] = hs->client_version >> 8; pms[1] = hs->client_version & 0xff; if (!RAND_bytes(&pms[2], SSL_MAX_MASTER_KEY_LENGTH - 2)) { return ssl_hs_error; } CBB enc_pms; uint8_t *ptr; size_t enc_pms_len; if (!CBB_add_u16_length_prefixed(&body, &enc_pms) || !CBB_reserve(&enc_pms, &ptr, RSA_size(rsa)) || !RSA_encrypt(rsa, &enc_pms_len, ptr, RSA_size(rsa), pms.data(), pms.size(), RSA_PKCS1_PADDING) || !CBB_did_write(&enc_pms, enc_pms_len) || !CBB_flush(&body)) { return ssl_hs_error; } } else if (alg_k & SSL_kECDHE) { // Generate a keypair and serialize the public half. CBB child; if (!CBB_add_u8_length_prefixed(&body, &child)) { return ssl_hs_error; } // Compute the premaster. uint8_t alert = SSL_AD_DECODE_ERROR; if (!hs->key_shares[0]->Accept(&child, &pms, &alert, hs->peer_key)) { ssl_send_alert(ssl, SSL3_AL_FATAL, alert); return ssl_hs_error; } if (!CBB_flush(&body)) { return ssl_hs_error; } // The key exchange state may now be discarded. hs->key_shares[0].reset(); hs->key_shares[1].reset(); hs->peer_key.Reset(); } else if (alg_k & SSL_kPSK) { // For plain PSK, other_secret is a block of 0s with the same length as // the pre-shared key. if (!pms.Init(psk_len)) { return ssl_hs_error; } OPENSSL_memset(pms.data(), 0, pms.size()); } else { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return ssl_hs_error; } // For a PSK cipher suite, other_secret is combined with the pre-shared // key. if (alg_a & SSL_aPSK) { ScopedCBB pms_cbb; CBB child; if (!CBB_init(pms_cbb.get(), 2 + psk_len + 2 + pms.size()) || !CBB_add_u16_length_prefixed(pms_cbb.get(), &child) || !CBB_add_bytes(&child, pms.data(), pms.size()) || !CBB_add_u16_length_prefixed(pms_cbb.get(), &child) || !CBB_add_bytes(&child, psk, psk_len) || !CBBFinishArray(pms_cbb.get(), &pms)) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return ssl_hs_error; } } // The message must be added to the finished hash before calculating the // master secret. if (!ssl_add_message_cbb(ssl, cbb.get())) { return ssl_hs_error; } hs->new_session->secret_length = tls1_generate_master_secret(hs, hs->new_session->secret, pms); if (hs->new_session->secret_length == 0) { return ssl_hs_error; } hs->new_session->extended_master_secret = hs->extended_master_secret; hs->state = state_send_client_certificate_verify; return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (!hs->cert_request || !ssl_has_certificate(hs)) { hs->state = state_send_client_finished; return ssl_hs_ok; } assert(ssl_has_private_key(hs)); ScopedCBB cbb; CBB body, child; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CERTIFICATE_VERIFY)) { return ssl_hs_error; } uint16_t signature_algorithm; if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); return ssl_hs_error; } if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) { // Write out the digest type in TLS 1.2. if (!CBB_add_u16(&body, signature_algorithm)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return ssl_hs_error; } } // Set aside space for the signature. const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get()); uint8_t *ptr; if (!CBB_add_u16_length_prefixed(&body, &child) || !CBB_reserve(&child, &ptr, max_sig_len)) { return ssl_hs_error; } size_t sig_len = max_sig_len; switch (ssl_private_key_sign(hs, ptr, &sig_len, max_sig_len, signature_algorithm, hs->transcript.buffer())) { case ssl_private_key_success: break; case ssl_private_key_failure: return ssl_hs_error; case ssl_private_key_retry: hs->state = state_send_client_certificate_verify; return ssl_hs_private_key_operation; } if (!CBB_did_write(&child, sig_len) || !ssl_add_message_cbb(ssl, cbb.get())) { return ssl_hs_error; } // The handshake buffer is no longer necessary. hs->transcript.FreeBuffer(); hs->state = state_send_client_finished; return ssl_hs_ok; } static enum ssl_hs_wait_t do_send_client_finished(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; hs->can_release_private_key = true; if (!ssl->method->add_change_cipher_spec(ssl) || !tls1_change_cipher_state(hs, evp_aead_seal)) { return ssl_hs_error; } if (hs->next_proto_neg_seen) { static const uint8_t kZero[32] = {0}; size_t padding_len = 32 - ((ssl->s3->next_proto_negotiated.size() + 2) % 32); ScopedCBB cbb; CBB body, child; if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_NEXT_PROTO) || !CBB_add_u8_length_prefixed(&body, &child) || !CBB_add_bytes(&child, ssl->s3->next_proto_negotiated.data(), ssl->s3->next_proto_negotiated.size()) || !CBB_add_u8_length_prefixed(&body, &child) || !CBB_add_bytes(&child, kZero, padding_len) || !ssl_add_message_cbb(ssl, cbb.get())) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return ssl_hs_error; } } 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())) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return ssl_hs_error; } } if (!ssl_send_finished(hs)) { return ssl_hs_error; } hs->state = state_finish_flight; return ssl_hs_flush; } static bool can_false_start(const SSL_HANDSHAKE *hs) { const SSL *const ssl = hs->ssl; // False Start bypasses the Finished check's downgrade protection. This can // enable attacks where we send data under weaker settings than supported // (e.g. the Logjam attack). Thus we require TLS 1.2 with an ECDHE+AEAD // cipher, our strongest settings before TLS 1.3. // // Now that TLS 1.3 exists, we would like to avoid similar attacks between // TLS 1.2 and TLS 1.3, but there are too many TLS 1.2 deployments to // sacrifice False Start on them. Instead, we rely on the ServerHello.random // downgrade signal, which we unconditionally enforce. if (SSL_is_dtls(ssl) || SSL_version(ssl) != TLS1_2_VERSION || hs->new_cipher->algorithm_mkey != SSL_kECDHE || hs->new_cipher->algorithm_mac != SSL_AEAD) { return false; } // If ECH was rejected, disable False Start. We run the handshake to // completion, including the Finished downgrade check, to authenticate the // recovery flow. if (ssl->s3->ech_status == ssl_ech_rejected) { return false; } // Additionally require ALPN or NPN by default. // // TODO(davidben): Can this constraint be relaxed globally now that cipher // suite requirements have been tightened? if (!ssl->ctx->false_start_allowed_without_alpn && ssl->s3->alpn_selected.empty() && ssl->s3->next_proto_negotiated.empty()) { return false; } return true; } static enum ssl_hs_wait_t do_finish_flight(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (ssl->session != NULL) { hs->state = state_finish_client_handshake; return ssl_hs_ok; } // This is a full handshake. If it involves ChannelID, then record the // handshake hashes at this point in the session so that any resumption of // this session with ChannelID can sign those hashes. if (!tls1_record_handshake_hashes_for_channel_id(hs)) { return ssl_hs_error; } hs->state = state_read_session_ticket; if ((SSL_get_mode(ssl) & SSL_MODE_ENABLE_FALSE_START) && can_false_start(hs) && // No False Start on renegotiation (would complicate the state machine). !ssl->s3->initial_handshake_complete) { hs->in_false_start = true; hs->can_early_write = true; return ssl_hs_early_return; } return ssl_hs_ok; } static enum ssl_hs_wait_t do_read_session_ticket(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (!hs->ticket_expected) { hs->state = state_process_change_cipher_spec; return ssl_hs_read_change_cipher_spec; } SSLMessage msg; if (!ssl->method->get_message(ssl, &msg)) { return ssl_hs_read_message; } if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEW_SESSION_TICKET) || !ssl_hash_message(hs, msg)) { return ssl_hs_error; } CBS new_session_ticket = msg.body, ticket; uint32_t ticket_lifetime_hint; if (!CBS_get_u32(&new_session_ticket, &ticket_lifetime_hint) || !CBS_get_u16_length_prefixed(&new_session_ticket, &ticket) || CBS_len(&new_session_ticket) != 0) { ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return ssl_hs_error; } if (CBS_len(&ticket) == 0) { // RFC 5077 allows a server to change its mind and send no ticket after // negotiating the extension. The value of |ticket_expected| is checked in // |ssl_update_cache| so is cleared here to avoid an unnecessary update. hs->ticket_expected = false; ssl->method->next_message(ssl); hs->state = state_process_change_cipher_spec; return ssl_hs_read_change_cipher_spec; } if (ssl->session != nullptr) { // The server is sending a new ticket for an existing session. Sessions are // immutable once established, so duplicate all but the ticket of the // existing session. assert(!hs->new_session); hs->new_session = SSL_SESSION_dup(ssl->session.get(), SSL_SESSION_INCLUDE_NONAUTH); if (!hs->new_session) { return ssl_hs_error; } } // |ticket_lifetime_hint| is measured from when the ticket was issued. ssl_session_rebase_time(ssl, hs->new_session.get()); if (!hs->new_session->ticket.CopyFrom(ticket)) { return ssl_hs_error; } hs->new_session->ticket_lifetime_hint = ticket_lifetime_hint; // Historically, OpenSSL filled in fake session IDs for ticket-based sessions. // TODO(davidben): Are external callers relying on this? Try removing this. SHA256(CBS_data(&ticket), CBS_len(&ticket), hs->new_session->session_id); hs->new_session->session_id_length = SHA256_DIGEST_LENGTH; ssl->method->next_message(ssl); hs->state = state_process_change_cipher_spec; return ssl_hs_read_change_cipher_spec; } static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) { if (!tls1_change_cipher_state(hs, evp_aead_open)) { return ssl_hs_error; } hs->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; enum ssl_hs_wait_t wait = ssl_get_finished(hs); if (wait != ssl_hs_ok) { return wait; } if (ssl->session != NULL) { hs->state = state_send_client_finished; return ssl_hs_ok; } hs->state = state_finish_client_handshake; return ssl_hs_ok; } static enum ssl_hs_wait_t do_finish_client_handshake(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; if (ssl->s3->ech_status == ssl_ech_rejected) { // Release the retry configs. hs->ech_authenticated_reject = true; ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ECH_REQUIRED); OPENSSL_PUT_ERROR(SSL, SSL_R_ECH_REJECTED); return ssl_hs_error; } ssl->method->on_handshake_complete(ssl); // Note TLS 1.2 resumptions with ticket renewal have both |ssl->session| (the // resumed session) and |hs->new_session| (the session with the new ticket). bool has_new_session = hs->new_session != nullptr; if (has_new_session) { // When False Start is enabled, the handshake reports completion early. The // caller may then have passed the (then unresuable) |hs->new_session| to // another thread via |SSL_get0_session| for resumption. To avoid potential // race conditions in such callers, we duplicate the session before // clearing |not_resumable|. ssl->s3->established_session = SSL_SESSION_dup(hs->new_session.get(), SSL_SESSION_DUP_ALL); if (!ssl->s3->established_session) { return ssl_hs_error; } // Renegotiations do not participate in session resumption. if (!ssl->s3->initial_handshake_complete) { ssl->s3->established_session->not_resumable = false; } hs->new_session.reset(); } else { assert(ssl->session != nullptr); ssl->s3->established_session = UpRef(ssl->session); } hs->handshake_finalized = true; ssl->s3->initial_handshake_complete = true; if (has_new_session) { ssl_update_cache(ssl); } hs->state = state_done; return ssl_hs_ok; } enum ssl_hs_wait_t ssl_client_handshake(SSL_HANDSHAKE *hs) { while (hs->state != state_done) { enum ssl_hs_wait_t ret = ssl_hs_error; enum ssl_client_hs_state_t state = static_cast(hs->state); switch (state) { case state_start_connect: ret = do_start_connect(hs); break; case state_enter_early_data: ret = do_enter_early_data(hs); break; case state_early_reverify_server_certificate: ret = do_early_reverify_server_certificate(hs); break; case state_read_hello_verify_request: ret = do_read_hello_verify_request(hs); break; case state_read_server_hello: ret = do_read_server_hello(hs); break; case state_tls13: ret = do_tls13(hs); break; case state_read_server_certificate: ret = do_read_server_certificate(hs); break; case state_read_certificate_status: ret = do_read_certificate_status(hs); break; case state_verify_server_certificate: ret = do_verify_server_certificate(hs); break; case state_reverify_server_certificate: ret = do_reverify_server_certificate(hs); break; case state_read_server_key_exchange: ret = do_read_server_key_exchange(hs); break; case state_read_certificate_request: ret = do_read_certificate_request(hs); break; case state_read_server_hello_done: ret = do_read_server_hello_done(hs); break; case state_send_client_certificate: ret = do_send_client_certificate(hs); break; case state_send_client_key_exchange: ret = do_send_client_key_exchange(hs); break; case state_send_client_certificate_verify: ret = do_send_client_certificate_verify(hs); break; case state_send_client_finished: ret = do_send_client_finished(hs); break; case state_finish_flight: ret = do_finish_flight(hs); break; case state_read_session_ticket: ret = do_read_session_ticket(hs); break; case state_process_change_cipher_spec: ret = do_process_change_cipher_spec(hs); break; case state_read_server_finished: ret = do_read_server_finished(hs); break; case state_finish_client_handshake: ret = do_finish_client_handshake(hs); break; case state_done: ret = ssl_hs_ok; break; } if (hs->state != state) { ssl_do_info_callback(hs->ssl, SSL_CB_CONNECT_LOOP, 1); } if (ret != ssl_hs_ok) { return ret; } } ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_DONE, 1); return ssl_hs_ok; } const char *ssl_client_handshake_state(SSL_HANDSHAKE *hs) { enum ssl_client_hs_state_t state = static_cast(hs->state); switch (state) { case state_start_connect: return "TLS client start_connect"; case state_enter_early_data: return "TLS client enter_early_data"; case state_early_reverify_server_certificate: return "TLS client early_reverify_server_certificate"; case state_read_hello_verify_request: return "TLS client read_hello_verify_request"; case state_read_server_hello: return "TLS client read_server_hello"; case state_tls13: return tls13_client_handshake_state(hs); case state_read_server_certificate: return "TLS client read_server_certificate"; case state_read_certificate_status: return "TLS client read_certificate_status"; case state_verify_server_certificate: return "TLS client verify_server_certificate"; case state_reverify_server_certificate: return "TLS client reverify_server_certificate"; case state_read_server_key_exchange: return "TLS client read_server_key_exchange"; case state_read_certificate_request: return "TLS client read_certificate_request"; case state_read_server_hello_done: return "TLS client read_server_hello_done"; case state_send_client_certificate: return "TLS client send_client_certificate"; case state_send_client_key_exchange: return "TLS client send_client_key_exchange"; case state_send_client_certificate_verify: return "TLS client send_client_certificate_verify"; case state_send_client_finished: return "TLS client send_client_finished"; case state_finish_flight: return "TLS client finish_flight"; case state_read_session_ticket: return "TLS client read_session_ticket"; case state_process_change_cipher_spec: return "TLS client process_change_cipher_spec"; case state_read_server_finished: return "TLS client read_server_finished"; case state_finish_client_handshake: return "TLS client finish_client_handshake"; case state_done: return "TLS client done"; } return "TLS client unknown"; } BSSL_NAMESPACE_END