/* 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 #include #include #include #include #include #include #include #include #include "../crypto/internal.h" #include "internal.h" /* kMaxKeyUpdates is the number of consecutive KeyUpdates that will be * processed. Without this limit an attacker could force unbounded processing * without being able to return application data. */ static const uint8_t kMaxKeyUpdates = 32; int tls13_handshake(SSL_HANDSHAKE *hs, int *out_early_return) { SSL *const ssl = hs->ssl; for (;;) { /* Resolve the operation the handshake was waiting on. */ switch (hs->wait) { case ssl_hs_error: OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_HANDSHAKE_FAILURE); return -1; case ssl_hs_flush: case ssl_hs_flush_and_read_message: { int ret = ssl->method->flush_flight(ssl); if (ret <= 0) { return ret; } if (hs->wait != ssl_hs_flush_and_read_message) { break; } ssl->method->expect_flight(ssl); hs->wait = ssl_hs_read_message; /* Fall-through. */ } case ssl_hs_read_message: { int ret = ssl->method->ssl_get_message(ssl); if (ret <= 0) { return ret; } break; } case ssl_hs_read_end_of_early_data: { if (ssl->s3->hs->can_early_read) { /* While we are processing early data, the handshake returns early. */ *out_early_return = 1; return 1; } hs->wait = ssl_hs_ok; break; } case ssl_hs_x509_lookup: ssl->rwstate = SSL_X509_LOOKUP; hs->wait = ssl_hs_ok; return -1; case ssl_hs_channel_id_lookup: ssl->rwstate = SSL_CHANNEL_ID_LOOKUP; hs->wait = ssl_hs_ok; return -1; case ssl_hs_private_key_operation: ssl->rwstate = SSL_PRIVATE_KEY_OPERATION; hs->wait = ssl_hs_ok; return -1; case ssl_hs_pending_ticket: ssl->rwstate = SSL_PENDING_TICKET; hs->wait = ssl_hs_ok; return -1; case ssl_hs_early_data_rejected: ssl->rwstate = SSL_EARLY_DATA_REJECTED; /* Cause |SSL_write| to start failing immediately. */ hs->can_early_write = 0; return -1; case ssl_hs_ok: break; } /* Run the state machine again. */ hs->wait = hs->do_tls13_handshake(hs); if (hs->wait == ssl_hs_error) { /* Don't loop around to avoid a stray |SSL_R_SSL_HANDSHAKE_FAILURE| the * first time around. */ return -1; } if (hs->wait == ssl_hs_ok) { /* The handshake has completed. */ return 1; } /* Otherwise, loop to the beginning and resolve what was blocking the * handshake. */ } } int tls13_get_cert_verify_signature_input( SSL_HANDSHAKE *hs, uint8_t **out, size_t *out_len, enum ssl_cert_verify_context_t cert_verify_context) { CBB cbb; if (!CBB_init(&cbb, 64 + 33 + 1 + 2 * EVP_MAX_MD_SIZE)) { goto err; } for (size_t i = 0; i < 64; i++) { if (!CBB_add_u8(&cbb, 0x20)) { goto err; } } const uint8_t *context; size_t context_len; if (cert_verify_context == ssl_cert_verify_server) { /* Include the NUL byte. */ static const char kContext[] = "TLS 1.3, server CertificateVerify"; context = (const uint8_t *)kContext; context_len = sizeof(kContext); } else if (cert_verify_context == ssl_cert_verify_client) { static const char kContext[] = "TLS 1.3, client CertificateVerify"; context = (const uint8_t *)kContext; context_len = sizeof(kContext); } else if (cert_verify_context == ssl_cert_verify_channel_id) { static const char kContext[] = "TLS 1.3, Channel ID"; context = (const uint8_t *)kContext; context_len = sizeof(kContext); } else { goto err; } if (!CBB_add_bytes(&cbb, context, context_len)) { goto err; } uint8_t context_hash[EVP_MAX_MD_SIZE]; size_t context_hash_len; if (!SSL_TRANSCRIPT_get_hash(&hs->transcript, context_hash, &context_hash_len) || !CBB_add_bytes(&cbb, context_hash, context_hash_len) || !CBB_finish(&cbb, out, out_len)) { goto err; } return 1; err: OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); CBB_cleanup(&cbb); return 0; } int tls13_process_certificate(SSL_HANDSHAKE *hs, int allow_anonymous) { SSL *const ssl = hs->ssl; CBS cbs, context, certificate_list; CBS_init(&cbs, ssl->init_msg, ssl->init_num); if (!CBS_get_u8_length_prefixed(&cbs, &context) || CBS_len(&context) != 0) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return 0; } const int retain_sha256 = ssl->server && ssl->retain_only_sha256_of_client_certs; int ret = 0; EVP_PKEY *pkey = NULL; STACK_OF(CRYPTO_BUFFER) *certs = sk_CRYPTO_BUFFER_new_null(); if (certs == NULL) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); goto err; } if (!CBS_get_u24_length_prefixed(&cbs, &certificate_list)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); goto err; } while (CBS_len(&certificate_list) > 0) { CBS certificate, extensions; if (!CBS_get_u24_length_prefixed(&certificate_list, &certificate) || !CBS_get_u16_length_prefixed(&certificate_list, &extensions) || CBS_len(&certificate) == 0) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_LENGTH_MISMATCH); goto err; } if (sk_CRYPTO_BUFFER_num(certs) == 0) { pkey = ssl_cert_parse_pubkey(&certificate); if (pkey == NULL) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); goto err; } /* TLS 1.3 always uses certificate keys for signing thus the correct * keyUsage is enforced. */ if (!ssl_cert_check_digital_signature_key_usage(&certificate)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); goto err; } if (retain_sha256) { /* Retain the hash of the leaf certificate if requested. */ SHA256(CBS_data(&certificate), CBS_len(&certificate), hs->new_session->peer_sha256); } } CRYPTO_BUFFER *buf = CRYPTO_BUFFER_new_from_CBS(&certificate, ssl->ctx->pool); if (buf == NULL || !sk_CRYPTO_BUFFER_push(certs, buf)) { CRYPTO_BUFFER_free(buf); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); goto err; } /* Parse out the extensions. */ int have_status_request = 0, have_sct = 0; CBS status_request, sct; const SSL_EXTENSION_TYPE ext_types[] = { {TLSEXT_TYPE_status_request, &have_status_request, &status_request}, {TLSEXT_TYPE_certificate_timestamp, &have_sct, &sct}, }; uint8_t alert = SSL_AD_DECODE_ERROR; if (!ssl_parse_extensions(&extensions, &alert, ext_types, OPENSSL_ARRAY_SIZE(ext_types), 0 /* reject unknown */)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); goto err; } /* All Certificate extensions are parsed, but only the leaf extensions are * stored. */ if (have_status_request) { if (ssl->server || !ssl->ocsp_stapling_enabled) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION); goto err; } uint8_t status_type; CBS ocsp_response; if (!CBS_get_u8(&status_request, &status_type) || status_type != TLSEXT_STATUSTYPE_ocsp || !CBS_get_u24_length_prefixed(&status_request, &ocsp_response) || CBS_len(&ocsp_response) == 0 || CBS_len(&status_request) != 0) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); goto err; } if (sk_CRYPTO_BUFFER_num(certs) == 1 && !CBS_stow(&ocsp_response, &hs->new_session->ocsp_response, &hs->new_session->ocsp_response_length)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); goto err; } } if (have_sct) { if (ssl->server || !ssl->signed_cert_timestamps_enabled) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION); goto err; } if (!ssl_is_sct_list_valid(&sct)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); goto err; } if (sk_CRYPTO_BUFFER_num(certs) == 1 && !CBS_stow( &sct, &hs->new_session->tlsext_signed_cert_timestamp_list, &hs->new_session->tlsext_signed_cert_timestamp_list_length)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); goto err; } } } if (CBS_len(&cbs) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); goto err; } EVP_PKEY_free(hs->peer_pubkey); hs->peer_pubkey = pkey; pkey = NULL; sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free); hs->new_session->certs = certs; certs = NULL; if (!ssl->ctx->x509_method->session_cache_objects(hs->new_session)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); goto err; } if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) == 0) { if (!allow_anonymous) { OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_CERTIFICATE_REQUIRED); goto err; } /* OpenSSL returns X509_V_OK when no certificates are requested. This is * classed by them as a bug, but it's assumed by at least NGINX. */ hs->new_session->verify_result = X509_V_OK; /* No certificate, so nothing more to do. */ ret = 1; goto err; } hs->new_session->peer_sha256_valid = retain_sha256; if (!ssl->ctx->x509_method->session_verify_cert_chain(hs->new_session, ssl)) { goto err; } ret = 1; err: sk_CRYPTO_BUFFER_pop_free(certs, CRYPTO_BUFFER_free); EVP_PKEY_free(pkey); return ret; } int tls13_process_certificate_verify(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; int ret = 0; uint8_t *msg = NULL; size_t msg_len; if (hs->peer_pubkey == NULL) { goto err; } CBS cbs, signature; uint16_t signature_algorithm; CBS_init(&cbs, ssl->init_msg, ssl->init_num); if (!CBS_get_u16(&cbs, &signature_algorithm) || !CBS_get_u16_length_prefixed(&cbs, &signature) || CBS_len(&cbs) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); goto err; } int al; if (!tls12_check_peer_sigalg(ssl, &al, signature_algorithm)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, al); goto err; } hs->new_session->peer_signature_algorithm = signature_algorithm; if (!tls13_get_cert_verify_signature_input( hs, &msg, &msg_len, ssl->server ? ssl_cert_verify_client : ssl_cert_verify_server)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); goto err; } int sig_ok = ssl_public_key_verify(ssl, CBS_data(&signature), CBS_len(&signature), signature_algorithm, hs->peer_pubkey, msg, msg_len); #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) sig_ok = 1; ERR_clear_error(); #endif if (!sig_ok) { OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); goto err; } ret = 1; err: OPENSSL_free(msg); return ret; } int tls13_process_finished(SSL_HANDSHAKE *hs, int use_saved_value) { SSL *const ssl = hs->ssl; uint8_t verify_data_buf[EVP_MAX_MD_SIZE]; const uint8_t *verify_data; size_t verify_data_len; if (use_saved_value) { assert(ssl->server); verify_data = hs->expected_client_finished; verify_data_len = hs->hash_len; } else { if (!tls13_finished_mac(hs, verify_data_buf, &verify_data_len, !ssl->server)) { return 0; } verify_data = verify_data_buf; } int finished_ok = ssl->init_num == verify_data_len && CRYPTO_memcmp(verify_data, ssl->init_msg, verify_data_len) == 0; #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) finished_ok = 1; #endif if (!finished_ok) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED); return 0; } return 1; } int tls13_add_certificate(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; CBB cbb, body, certificate_list; if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_CERTIFICATE) || /* The request context is always empty in the handshake. */ !CBB_add_u8(&body, 0) || !CBB_add_u24_length_prefixed(&body, &certificate_list)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } if (!ssl_has_certificate(ssl)) { if (!ssl_add_message_cbb(ssl, &cbb)) { goto err; } return 1; } CERT *cert = ssl->cert; CRYPTO_BUFFER *leaf_buf = sk_CRYPTO_BUFFER_value(cert->chain, 0); CBB leaf, extensions; if (!CBB_add_u24_length_prefixed(&certificate_list, &leaf) || !CBB_add_bytes(&leaf, CRYPTO_BUFFER_data(leaf_buf), CRYPTO_BUFFER_len(leaf_buf)) || !CBB_add_u16_length_prefixed(&certificate_list, &extensions)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } if (hs->scts_requested && ssl->cert->signed_cert_timestamp_list != NULL) { CBB contents; if (!CBB_add_u16(&extensions, TLSEXT_TYPE_certificate_timestamp) || !CBB_add_u16_length_prefixed(&extensions, &contents) || !CBB_add_bytes( &contents, CRYPTO_BUFFER_data(ssl->cert->signed_cert_timestamp_list), CRYPTO_BUFFER_len(ssl->cert->signed_cert_timestamp_list)) || !CBB_flush(&extensions)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } } if (hs->ocsp_stapling_requested && ssl->cert->ocsp_response != NULL) { CBB contents, ocsp_response; if (!CBB_add_u16(&extensions, TLSEXT_TYPE_status_request) || !CBB_add_u16_length_prefixed(&extensions, &contents) || !CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) || !CBB_add_u24_length_prefixed(&contents, &ocsp_response) || !CBB_add_bytes(&ocsp_response, CRYPTO_BUFFER_data(ssl->cert->ocsp_response), CRYPTO_BUFFER_len(ssl->cert->ocsp_response)) || !CBB_flush(&extensions)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } } for (size_t i = 1; i < sk_CRYPTO_BUFFER_num(cert->chain); i++) { CRYPTO_BUFFER *cert_buf = sk_CRYPTO_BUFFER_value(cert->chain, i); CBB child; if (!CBB_add_u24_length_prefixed(&certificate_list, &child) || !CBB_add_bytes(&child, CRYPTO_BUFFER_data(cert_buf), CRYPTO_BUFFER_len(cert_buf)) || !CBB_add_u16(&certificate_list, 0 /* no extensions */)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } } if (!ssl_add_message_cbb(ssl, &cbb)) { goto err; } return 1; err: CBB_cleanup(&cbb); return 0; } enum ssl_private_key_result_t tls13_add_certificate_verify(SSL_HANDSHAKE *hs, int is_first_run) { SSL *const ssl = hs->ssl; enum ssl_private_key_result_t ret = ssl_private_key_failure; uint8_t *msg = NULL; size_t msg_len; CBB cbb, body; CBB_zero(&cbb); uint16_t signature_algorithm; if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) { goto err; } if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_CERTIFICATE_VERIFY) || !CBB_add_u16(&body, signature_algorithm)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } /* Sign the digest. */ CBB child; const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey); uint8_t *sig; size_t sig_len; if (!CBB_add_u16_length_prefixed(&body, &child) || !CBB_reserve(&child, &sig, max_sig_len)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); goto err; } enum ssl_private_key_result_t sign_result; if (is_first_run) { if (!tls13_get_cert_verify_signature_input( hs, &msg, &msg_len, ssl->server ? ssl_cert_verify_server : ssl_cert_verify_client)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); goto err; } sign_result = ssl_private_key_sign(ssl, sig, &sig_len, max_sig_len, signature_algorithm, msg, msg_len); } else { sign_result = ssl_private_key_complete(ssl, sig, &sig_len, max_sig_len); } if (sign_result != ssl_private_key_success) { ret = sign_result; goto err; } if (!CBB_did_write(&child, sig_len) || !ssl_add_message_cbb(ssl, &cbb)) { goto err; } ret = ssl_private_key_success; err: CBB_cleanup(&cbb); OPENSSL_free(msg); return ret; } int tls13_add_finished(SSL_HANDSHAKE *hs) { SSL *const ssl = hs->ssl; size_t verify_data_len; uint8_t verify_data[EVP_MAX_MD_SIZE]; if (!tls13_finished_mac(hs, verify_data, &verify_data_len, ssl->server)) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED); return 0; } CBB cbb, body; if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_FINISHED) || !CBB_add_bytes(&body, verify_data, verify_data_len) || !ssl_add_message_cbb(ssl, &cbb)) { CBB_cleanup(&cbb); return 0; } return 1; } static int tls13_receive_key_update(SSL *ssl) { CBS cbs; uint8_t key_update_request; CBS_init(&cbs, ssl->init_msg, ssl->init_num); if (!CBS_get_u8(&cbs, &key_update_request) || CBS_len(&cbs) != 0 || (key_update_request != SSL_KEY_UPDATE_NOT_REQUESTED && key_update_request != SSL_KEY_UPDATE_REQUESTED)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return 0; } if (!tls13_rotate_traffic_key(ssl, evp_aead_open)) { return 0; } /* Acknowledge the KeyUpdate */ if (key_update_request == SSL_KEY_UPDATE_REQUESTED && !ssl->s3->key_update_pending) { CBB cbb, body; if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_KEY_UPDATE) || !CBB_add_u8(&body, SSL_KEY_UPDATE_NOT_REQUESTED) || !ssl_add_message_cbb(ssl, &cbb) || !tls13_rotate_traffic_key(ssl, evp_aead_seal)) { CBB_cleanup(&cbb); return 0; } /* Suppress KeyUpdate acknowledgments until this change is written to the * wire. This prevents us from accumulating write obligations when read and * write progress at different rates. See draft-ietf-tls-tls13-18, section * 4.5.3. */ ssl->s3->key_update_pending = 1; } return 1; } int tls13_post_handshake(SSL *ssl) { if (ssl->s3->tmp.message_type == SSL3_MT_KEY_UPDATE) { ssl->s3->key_update_count++; if (ssl->s3->key_update_count > kMaxKeyUpdates) { OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_KEY_UPDATES); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); return 0; } return tls13_receive_key_update(ssl); } ssl->s3->key_update_count = 0; if (ssl->s3->tmp.message_type == SSL3_MT_NEW_SESSION_TICKET && !ssl->server) { return tls13_process_new_session_ticket(ssl); } ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); return 0; }