/* $OpenBSD: tls13_client.c,v 1.94 2022/02/03 16:33:12 jsing Exp $ */ /* * Copyright (c) 2018, 2019 Joel Sing * * Permission to use, copy, modify, and 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 "bytestring.h" #include "ssl_locl.h" #include "ssl_sigalgs.h" #include "ssl_tlsext.h" #include "tls13_handshake.h" #include "tls13_internal.h" int tls13_client_init(struct tls13_ctx *ctx) { const uint16_t *groups; size_t groups_len; SSL *s = ctx->ssl; if (!ssl_supported_tls_version_range(s, &ctx->hs->our_min_tls_version, &ctx->hs->our_max_tls_version)) { SSLerror(s, SSL_R_NO_PROTOCOLS_AVAILABLE); return 0; } s->version = ctx->hs->our_max_tls_version; tls13_record_layer_set_retry_after_phh(ctx->rl, (s->internal->mode & SSL_MODE_AUTO_RETRY) != 0); if (!ssl_get_new_session(s, 0)) /* XXX */ return 0; if (!tls1_transcript_init(s)) return 0; /* Generate a key share using our preferred group. */ tls1_get_group_list(s, 0, &groups, &groups_len); if (groups_len < 1) return 0; if ((ctx->hs->key_share = tls_key_share_new(groups[0])) == NULL) return 0; if (!tls_key_share_generate(ctx->hs->key_share)) return 0; arc4random_buf(s->s3->client_random, SSL3_RANDOM_SIZE); /* * The legacy session identifier should either be set to an * unpredictable 32-byte value or zero length... a non-zero length * legacy session identifier triggers compatibility mode (see RFC 8446 * Appendix D.4). In the pre-TLSv1.3 case a zero length value is used. */ if (ctx->middlebox_compat && ctx->hs->our_max_tls_version >= TLS1_3_VERSION) { arc4random_buf(ctx->hs->tls13.legacy_session_id, sizeof(ctx->hs->tls13.legacy_session_id)); ctx->hs->tls13.legacy_session_id_len = sizeof(ctx->hs->tls13.legacy_session_id); } return 1; } int tls13_client_connect(struct tls13_ctx *ctx) { if (ctx->mode != TLS13_HS_CLIENT) return TLS13_IO_FAILURE; return tls13_handshake_perform(ctx); } static int tls13_client_hello_build(struct tls13_ctx *ctx, CBB *cbb) { CBB cipher_suites, compression_methods, session_id; uint16_t client_version; SSL *s = ctx->ssl; /* Legacy client version is capped at TLS 1.2. */ if (!ssl_max_legacy_version(s, &client_version)) goto err; if (!CBB_add_u16(cbb, client_version)) goto err; if (!CBB_add_bytes(cbb, s->s3->client_random, SSL3_RANDOM_SIZE)) goto err; if (!CBB_add_u8_length_prefixed(cbb, &session_id)) goto err; if (!CBB_add_bytes(&session_id, ctx->hs->tls13.legacy_session_id, ctx->hs->tls13.legacy_session_id_len)) goto err; if (!CBB_add_u16_length_prefixed(cbb, &cipher_suites)) goto err; if (!ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), &cipher_suites)) { SSLerror(s, SSL_R_NO_CIPHERS_AVAILABLE); goto err; } if (!CBB_add_u8_length_prefixed(cbb, &compression_methods)) goto err; if (!CBB_add_u8(&compression_methods, 0)) goto err; if (!tlsext_client_build(s, SSL_TLSEXT_MSG_CH, cbb)) goto err; if (!CBB_flush(cbb)) goto err; return 1; err: return 0; } int tls13_client_hello_send(struct tls13_ctx *ctx, CBB *cbb) { if (ctx->hs->our_min_tls_version < TLS1_2_VERSION) tls13_record_layer_set_legacy_version(ctx->rl, TLS1_VERSION); /* We may receive a pre-TLSv1.3 alert in response to the client hello. */ tls13_record_layer_allow_legacy_alerts(ctx->rl, 1); if (!tls13_client_hello_build(ctx, cbb)) return 0; return 1; } int tls13_client_hello_sent(struct tls13_ctx *ctx) { tls13_record_layer_allow_ccs(ctx->rl, 1); tls1_transcript_freeze(ctx->ssl); if (ctx->middlebox_compat) ctx->send_dummy_ccs = 1; return 1; } static int tls13_server_hello_is_legacy(CBS *cbs) { CBS extensions_block, extensions, extension_data; uint16_t selected_version = 0; uint16_t type; CBS_dup(cbs, &extensions_block); if (!CBS_get_u16_length_prefixed(&extensions_block, &extensions)) return 1; while (CBS_len(&extensions) > 0) { if (!CBS_get_u16(&extensions, &type)) return 1; if (!CBS_get_u16_length_prefixed(&extensions, &extension_data)) return 1; if (type != TLSEXT_TYPE_supported_versions) continue; if (!CBS_get_u16(&extension_data, &selected_version)) return 1; if (CBS_len(&extension_data) != 0) return 1; } return (selected_version < TLS1_3_VERSION); } static int tls13_server_hello_is_retry(CBS *cbs) { CBS server_hello, server_random; uint16_t legacy_version; CBS_dup(cbs, &server_hello); if (!CBS_get_u16(&server_hello, &legacy_version)) return 0; if (!CBS_get_bytes(&server_hello, &server_random, SSL3_RANDOM_SIZE)) return 0; /* See if this is a HelloRetryRequest. */ return CBS_mem_equal(&server_random, tls13_hello_retry_request_hash, sizeof(tls13_hello_retry_request_hash)); } static int tls13_server_hello_process(struct tls13_ctx *ctx, CBS *cbs) { CBS server_random, session_id; uint16_t tlsext_msg_type = SSL_TLSEXT_MSG_SH; uint16_t cipher_suite, legacy_version; uint8_t compression_method; const SSL_CIPHER *cipher; int alert_desc; SSL *s = ctx->ssl; if (!CBS_get_u16(cbs, &legacy_version)) goto err; if (!CBS_get_bytes(cbs, &server_random, SSL3_RANDOM_SIZE)) goto err; if (!CBS_get_u8_length_prefixed(cbs, &session_id)) goto err; if (!CBS_get_u16(cbs, &cipher_suite)) goto err; if (!CBS_get_u8(cbs, &compression_method)) goto err; if (tls13_server_hello_is_legacy(cbs)) { if (ctx->hs->our_max_tls_version >= TLS1_3_VERSION) { /* * RFC 8446 section 4.1.3: we must not downgrade if * the server random value contains the TLS 1.2 or 1.1 * magical value. */ if (!CBS_skip(&server_random, CBS_len(&server_random) - sizeof(tls13_downgrade_12))) goto err; if (CBS_mem_equal(&server_random, tls13_downgrade_12, sizeof(tls13_downgrade_12)) || CBS_mem_equal(&server_random, tls13_downgrade_11, sizeof(tls13_downgrade_11))) { ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; goto err; } } if (!CBS_skip(cbs, CBS_len(cbs))) goto err; ctx->hs->tls13.use_legacy = 1; return 1; } /* From here on in we know we are doing TLSv1.3. */ tls13_record_layer_set_legacy_version(ctx->rl, TLS1_2_VERSION); tls13_record_layer_allow_legacy_alerts(ctx->rl, 0); /* See if this is a HelloRetryRequest. */ /* XXX - see if we can avoid doing this twice. */ if (CBS_mem_equal(&server_random, tls13_hello_retry_request_hash, sizeof(tls13_hello_retry_request_hash))) { tlsext_msg_type = SSL_TLSEXT_MSG_HRR; ctx->hs->tls13.hrr = 1; } if (!tlsext_client_parse(s, tlsext_msg_type, cbs, &alert_desc)) { ctx->alert = alert_desc; goto err; } /* * The supported versions extension indicated 0x0304 or greater. * Ensure that it was 0x0304 and that legacy version is set to 0x0303 * (RFC 8446 section 4.2.1). */ if (ctx->hs->tls13.server_version != TLS1_3_VERSION || legacy_version != TLS1_2_VERSION) { ctx->alert = TLS13_ALERT_PROTOCOL_VERSION; goto err; } ctx->hs->negotiated_tls_version = ctx->hs->tls13.server_version; ctx->hs->peer_legacy_version = legacy_version; /* The session_id must match. */ if (!CBS_mem_equal(&session_id, ctx->hs->tls13.legacy_session_id, ctx->hs->tls13.legacy_session_id_len)) { ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; goto err; } /* * Ensure that the cipher suite is one that we offered in the client * hello and that it is a TLSv1.3 cipher suite. */ cipher = ssl3_get_cipher_by_value(cipher_suite); if (cipher == NULL || !ssl_cipher_in_list(SSL_get_ciphers(s), cipher)) { ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; goto err; } if (cipher->algorithm_ssl != SSL_TLSV1_3) { ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; goto err; } if (!(ctx->handshake_stage.hs_type & WITHOUT_HRR) && !ctx->hs->tls13.hrr) { /* * A ServerHello following a HelloRetryRequest MUST use the same * cipher suite (RFC 8446 section 4.1.4). */ if (ctx->hs->cipher != cipher) { ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; goto err; } } ctx->hs->cipher = cipher; if (compression_method != 0) { ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; goto err; } return 1; err: if (ctx->alert == 0) ctx->alert = TLS13_ALERT_DECODE_ERROR; return 0; } static int tls13_client_engage_record_protection(struct tls13_ctx *ctx) { struct tls13_secrets *secrets; struct tls13_secret context; unsigned char buf[EVP_MAX_MD_SIZE]; uint8_t *shared_key = NULL; size_t shared_key_len = 0; size_t hash_len; SSL *s = ctx->ssl; int ret = 0; /* Derive the shared key and engage record protection. */ if (!tls_key_share_derive(ctx->hs->key_share, &shared_key, &shared_key_len)) goto err; s->session->cipher = ctx->hs->cipher; s->session->ssl_version = ctx->hs->tls13.server_version; if ((ctx->aead = tls13_cipher_aead(ctx->hs->cipher)) == NULL) goto err; if ((ctx->hash = tls13_cipher_hash(ctx->hs->cipher)) == NULL) goto err; if ((secrets = tls13_secrets_create(ctx->hash, 0)) == NULL) goto err; ctx->hs->tls13.secrets = secrets; /* XXX - pass in hash. */ if (!tls1_transcript_hash_init(s)) goto err; tls1_transcript_free(s); if (!tls1_transcript_hash_value(s, buf, sizeof(buf), &hash_len)) goto err; context.data = buf; context.len = hash_len; /* Early secrets. */ if (!tls13_derive_early_secrets(secrets, secrets->zeros.data, secrets->zeros.len, &context)) goto err; /* Handshake secrets. */ if (!tls13_derive_handshake_secrets(ctx->hs->tls13.secrets, shared_key, shared_key_len, &context)) goto err; tls13_record_layer_set_aead(ctx->rl, ctx->aead); tls13_record_layer_set_hash(ctx->rl, ctx->hash); if (!tls13_record_layer_set_read_traffic_key(ctx->rl, &secrets->server_handshake_traffic)) goto err; if (!tls13_record_layer_set_write_traffic_key(ctx->rl, &secrets->client_handshake_traffic)) goto err; ret = 1; err: freezero(shared_key, shared_key_len); return ret; } int tls13_server_hello_retry_request_recv(struct tls13_ctx *ctx, CBS *cbs) { /* * The state machine has no way of knowing if we're going to receive a * HelloRetryRequest or a ServerHello. As such, we have to handle * this case here and hand off to the appropriate function. */ if (!tls13_server_hello_is_retry(cbs)) { ctx->handshake_stage.hs_type |= WITHOUT_HRR; return tls13_server_hello_recv(ctx, cbs); } if (!tls13_server_hello_process(ctx, cbs)) return 0; /* * This may have been a TLSv1.2 or earlier ServerHello that just * happened to have matching server random... */ if (ctx->hs->tls13.use_legacy) return tls13_use_legacy_client(ctx); if (!ctx->hs->tls13.hrr) return 0; if (!tls13_synthetic_handshake_message(ctx)) return 0; if (!tls13_handshake_msg_record(ctx)) return 0; ctx->hs->tls13.hrr = 0; return 1; } int tls13_client_hello_retry_send(struct tls13_ctx *ctx, CBB *cbb) { /* * Ensure that the server supported group is one that we listed in our * supported groups and is not the same as the key share we previously * offered. */ if (!tls1_check_curve(ctx->ssl, ctx->hs->tls13.server_group)) return 0; /* XXX alert */ if (ctx->hs->tls13.server_group == tls_key_share_group(ctx->hs->key_share)) return 0; /* XXX alert */ /* Switch to new key share. */ tls_key_share_free(ctx->hs->key_share); if ((ctx->hs->key_share = tls_key_share_new(ctx->hs->tls13.server_group)) == NULL) return 0; if (!tls_key_share_generate(ctx->hs->key_share)) return 0; if (!tls13_client_hello_build(ctx, cbb)) return 0; return 1; } int tls13_server_hello_recv(struct tls13_ctx *ctx, CBS *cbs) { SSL *s = ctx->ssl; /* * We may have received a legacy (pre-TLSv1.3) ServerHello or a TLSv1.3 * ServerHello. HelloRetryRequests have already been handled. */ if (!tls13_server_hello_process(ctx, cbs)) return 0; if (ctx->handshake_stage.hs_type & WITHOUT_HRR) { tls1_transcript_unfreeze(s); if (!tls13_handshake_msg_record(ctx)) return 0; } if (ctx->hs->tls13.use_legacy) { if (!(ctx->handshake_stage.hs_type & WITHOUT_HRR)) return 0; return tls13_use_legacy_client(ctx); } if (ctx->hs->tls13.hrr) { /* The server has sent two HelloRetryRequests. */ ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER; return 0; } if (!tls13_client_engage_record_protection(ctx)) return 0; ctx->handshake_stage.hs_type |= NEGOTIATED; return 1; } int tls13_server_encrypted_extensions_recv(struct tls13_ctx *ctx, CBS *cbs) { int alert_desc; if (!tlsext_client_parse(ctx->ssl, SSL_TLSEXT_MSG_EE, cbs, &alert_desc)) { ctx->alert = alert_desc; goto err; } return 1; err: if (ctx->alert == 0) ctx->alert = TLS13_ALERT_DECODE_ERROR; return 0; } int tls13_server_certificate_request_recv(struct tls13_ctx *ctx, CBS *cbs) { CBS cert_request_context; int alert_desc; /* * Thanks to poor state design in the RFC, this function can be called * when we actually have a certificate message instead of a certificate * request... in that case we call the certificate handler after * switching state, to avoid advancing state. */ if (tls13_handshake_msg_type(ctx->hs_msg) == TLS13_MT_CERTIFICATE) { ctx->handshake_stage.hs_type |= WITHOUT_CR; return tls13_server_certificate_recv(ctx, cbs); } if (!CBS_get_u8_length_prefixed(cbs, &cert_request_context)) goto err; if (CBS_len(&cert_request_context) != 0) goto err; if (!tlsext_client_parse(ctx->ssl, SSL_TLSEXT_MSG_CR, cbs, &alert_desc)) { ctx->alert = alert_desc; goto err; } return 1; err: if (ctx->alert == 0) ctx->alert = TLS13_ALERT_DECODE_ERROR; return 0; } int tls13_server_certificate_recv(struct tls13_ctx *ctx, CBS *cbs) { CBS cert_request_context, cert_list, cert_data; struct stack_st_X509 *certs = NULL; SSL *s = ctx->ssl; X509 *cert = NULL; EVP_PKEY *pkey; const uint8_t *p; int alert_desc, cert_type; int ret = 0; if ((certs = sk_X509_new_null()) == NULL) goto err; if (!CBS_get_u8_length_prefixed(cbs, &cert_request_context)) goto err; if (CBS_len(&cert_request_context) != 0) goto err; if (!CBS_get_u24_length_prefixed(cbs, &cert_list)) goto err; while (CBS_len(&cert_list) > 0) { if (!CBS_get_u24_length_prefixed(&cert_list, &cert_data)) goto err; if (!tlsext_client_parse(ctx->ssl, SSL_TLSEXT_MSG_CT, &cert_list, &alert_desc)) { ctx->alert = alert_desc; goto err; } p = CBS_data(&cert_data); if ((cert = d2i_X509(NULL, &p, CBS_len(&cert_data))) == NULL) goto err; if (p != CBS_data(&cert_data) + CBS_len(&cert_data)) goto err; if (!sk_X509_push(certs, cert)) goto err; cert = NULL; } /* A server must always provide a non-empty certificate list. */ if (sk_X509_num(certs) < 1) { ctx->alert = TLS13_ALERT_DECODE_ERROR; tls13_set_errorx(ctx, TLS13_ERR_NO_PEER_CERTIFICATE, 0, "peer failed to provide a certificate", NULL); goto err; } /* * At this stage we still have no proof of possession. As such, it would * be preferable to keep the chain and verify once we have successfully * processed the CertificateVerify message. */ if (ssl_verify_cert_chain(s, certs) <= 0 && s->verify_mode != SSL_VERIFY_NONE) { ctx->alert = ssl_verify_alarm_type(s->verify_result); tls13_set_errorx(ctx, TLS13_ERR_VERIFY_FAILED, 0, "failed to verify peer certificate", NULL); goto err; } ERR_clear_error(); cert = sk_X509_value(certs, 0); X509_up_ref(cert); if ((pkey = X509_get0_pubkey(cert)) == NULL) goto err; if (EVP_PKEY_missing_parameters(pkey)) goto err; if ((cert_type = ssl_cert_type(pkey)) < 0) goto err; X509_up_ref(cert); X509_free(s->session->peer_cert); s->session->peer_cert = cert; s->session->peer_cert_type = cert_type; s->session->verify_result = s->verify_result; sk_X509_pop_free(s->session->cert_chain, X509_free); s->session->cert_chain = certs; certs = NULL; if (ctx->ocsp_status_recv_cb != NULL && !ctx->ocsp_status_recv_cb(ctx)) goto err; ret = 1; err: sk_X509_pop_free(certs, X509_free); X509_free(cert); return ret; } int tls13_server_certificate_verify_recv(struct tls13_ctx *ctx, CBS *cbs) { const struct ssl_sigalg *sigalg; uint16_t signature_scheme; uint8_t *sig_content = NULL; size_t sig_content_len; EVP_MD_CTX *mdctx = NULL; EVP_PKEY_CTX *pctx; EVP_PKEY *pkey; X509 *cert; CBS signature; CBB cbb; int ret = 0; memset(&cbb, 0, sizeof(cbb)); if (!CBS_get_u16(cbs, &signature_scheme)) goto err; if (!CBS_get_u16_length_prefixed(cbs, &signature)) goto err; if (!CBB_init(&cbb, 0)) goto err; if (!CBB_add_bytes(&cbb, tls13_cert_verify_pad, sizeof(tls13_cert_verify_pad))) goto err; if (!CBB_add_bytes(&cbb, tls13_cert_server_verify_context, strlen(tls13_cert_server_verify_context))) goto err; if (!CBB_add_u8(&cbb, 0)) goto err; if (!CBB_add_bytes(&cbb, ctx->hs->tls13.transcript_hash, ctx->hs->tls13.transcript_hash_len)) goto err; if (!CBB_finish(&cbb, &sig_content, &sig_content_len)) goto err; if ((cert = ctx->ssl->session->peer_cert) == NULL) goto err; if ((pkey = X509_get0_pubkey(cert)) == NULL) goto err; if ((sigalg = ssl_sigalg_for_peer(ctx->ssl, pkey, signature_scheme)) == NULL) goto err; ctx->hs->peer_sigalg = sigalg; if (CBS_len(&signature) > EVP_PKEY_size(pkey)) goto err; if ((mdctx = EVP_MD_CTX_new()) == NULL) goto err; if (!EVP_DigestVerifyInit(mdctx, &pctx, sigalg->md(), NULL, pkey)) goto err; if (sigalg->flags & SIGALG_FLAG_RSA_PSS) { if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING)) goto err; if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1)) goto err; } if (!EVP_DigestVerifyUpdate(mdctx, sig_content, sig_content_len)) { ctx->alert = TLS13_ALERT_DECRYPT_ERROR; goto err; } if (EVP_DigestVerifyFinal(mdctx, CBS_data(&signature), CBS_len(&signature)) <= 0) { ctx->alert = TLS13_ALERT_DECRYPT_ERROR; goto err; } ret = 1; err: if (!ret && ctx->alert == 0) ctx->alert = TLS13_ALERT_DECODE_ERROR; CBB_cleanup(&cbb); EVP_MD_CTX_free(mdctx); free(sig_content); return ret; } int tls13_server_finished_recv(struct tls13_ctx *ctx, CBS *cbs) { struct tls13_secrets *secrets = ctx->hs->tls13.secrets; struct tls13_secret context = { .data = "", .len = 0 }; struct tls13_secret finished_key; uint8_t transcript_hash[EVP_MAX_MD_SIZE]; size_t transcript_hash_len; uint8_t *verify_data = NULL; size_t verify_data_len; uint8_t key[EVP_MAX_MD_SIZE]; HMAC_CTX *hmac_ctx = NULL; unsigned int hlen; int ret = 0; /* * Verify server finished. */ finished_key.data = key; finished_key.len = EVP_MD_size(ctx->hash); if (!tls13_hkdf_expand_label(&finished_key, ctx->hash, &secrets->server_handshake_traffic, "finished", &context)) goto err; if ((hmac_ctx = HMAC_CTX_new()) == NULL) goto err; if (!HMAC_Init_ex(hmac_ctx, finished_key.data, finished_key.len, ctx->hash, NULL)) goto err; if (!HMAC_Update(hmac_ctx, ctx->hs->tls13.transcript_hash, ctx->hs->tls13.transcript_hash_len)) goto err; verify_data_len = HMAC_size(hmac_ctx); if ((verify_data = calloc(1, verify_data_len)) == NULL) goto err; if (!HMAC_Final(hmac_ctx, verify_data, &hlen)) goto err; if (hlen != verify_data_len) goto err; if (!CBS_mem_equal(cbs, verify_data, verify_data_len)) { ctx->alert = TLS13_ALERT_DECRYPT_ERROR; goto err; } if (!CBS_write_bytes(cbs, ctx->hs->peer_finished, sizeof(ctx->hs->peer_finished), &ctx->hs->peer_finished_len)) goto err; if (!CBS_skip(cbs, verify_data_len)) goto err; /* * Derive application traffic keys. */ if (!tls1_transcript_hash_value(ctx->ssl, transcript_hash, sizeof(transcript_hash), &transcript_hash_len)) goto err; context.data = transcript_hash; context.len = transcript_hash_len; if (!tls13_derive_application_secrets(secrets, &context)) goto err; /* * Any records following the server finished message must be encrypted * using the server application traffic keys. */ if (!tls13_record_layer_set_read_traffic_key(ctx->rl, &secrets->server_application_traffic)) goto err; tls13_record_layer_allow_ccs(ctx->rl, 0); ret = 1; err: HMAC_CTX_free(hmac_ctx); free(verify_data); return ret; } static int tls13_client_check_certificate(struct tls13_ctx *ctx, SSL_CERT_PKEY *cpk, int *ok, const struct ssl_sigalg **out_sigalg) { const struct ssl_sigalg *sigalg; SSL *s = ctx->ssl; *ok = 0; *out_sigalg = NULL; if (cpk->x509 == NULL || cpk->privatekey == NULL) goto done; if ((sigalg = ssl_sigalg_select(s, cpk->privatekey)) == NULL) goto done; *ok = 1; *out_sigalg = sigalg; done: return 1; } static int tls13_client_select_certificate(struct tls13_ctx *ctx, SSL_CERT_PKEY **out_cpk, const struct ssl_sigalg **out_sigalg) { SSL *s = ctx->ssl; const struct ssl_sigalg *sigalg; SSL_CERT_PKEY *cpk; int cert_ok; *out_cpk = NULL; *out_sigalg = NULL; /* * XXX - RFC 8446, 4.4.2.3: the server can communicate preferences * with the certificate_authorities (4.2.4) and oid_filters (4.2.5) * extensions. We should honor the former and must apply the latter. */ cpk = &s->cert->pkeys[SSL_PKEY_ECC]; if (!tls13_client_check_certificate(ctx, cpk, &cert_ok, &sigalg)) return 0; if (cert_ok) goto done; cpk = &s->cert->pkeys[SSL_PKEY_RSA]; if (!tls13_client_check_certificate(ctx, cpk, &cert_ok, &sigalg)) return 0; if (cert_ok) goto done; cpk = NULL; sigalg = NULL; done: *out_cpk = cpk; *out_sigalg = sigalg; return 1; } int tls13_client_certificate_send(struct tls13_ctx *ctx, CBB *cbb) { SSL *s = ctx->ssl; CBB cert_request_context, cert_list; const struct ssl_sigalg *sigalg; STACK_OF(X509) *chain; SSL_CERT_PKEY *cpk; X509 *cert; int i, ret = 0; if (!tls13_client_select_certificate(ctx, &cpk, &sigalg)) goto err; ctx->hs->tls13.cpk = cpk; ctx->hs->our_sigalg = sigalg; if (!CBB_add_u8_length_prefixed(cbb, &cert_request_context)) goto err; if (!CBB_add_u24_length_prefixed(cbb, &cert_list)) goto err; /* No certificate selected. */ if (cpk == NULL) goto done; if ((chain = cpk->chain) == NULL) chain = s->ctx->extra_certs; if (!tls13_cert_add(ctx, &cert_list, cpk->x509, tlsext_client_build)) goto err; for (i = 0; i < sk_X509_num(chain); i++) { cert = sk_X509_value(chain, i); if (!tls13_cert_add(ctx, &cert_list, cert, tlsext_client_build)) goto err; } ctx->handshake_stage.hs_type |= WITH_CCV; done: if (!CBB_flush(cbb)) goto err; ret = 1; err: return ret; } int tls13_client_certificate_verify_send(struct tls13_ctx *ctx, CBB *cbb) { const struct ssl_sigalg *sigalg; uint8_t *sig = NULL, *sig_content = NULL; size_t sig_len, sig_content_len; EVP_MD_CTX *mdctx = NULL; EVP_PKEY_CTX *pctx; EVP_PKEY *pkey; const SSL_CERT_PKEY *cpk; CBB sig_cbb; int ret = 0; memset(&sig_cbb, 0, sizeof(sig_cbb)); if ((cpk = ctx->hs->tls13.cpk) == NULL) goto err; if ((sigalg = ctx->hs->our_sigalg) == NULL) goto err; pkey = cpk->privatekey; if (!CBB_init(&sig_cbb, 0)) goto err; if (!CBB_add_bytes(&sig_cbb, tls13_cert_verify_pad, sizeof(tls13_cert_verify_pad))) goto err; if (!CBB_add_bytes(&sig_cbb, tls13_cert_client_verify_context, strlen(tls13_cert_client_verify_context))) goto err; if (!CBB_add_u8(&sig_cbb, 0)) goto err; if (!CBB_add_bytes(&sig_cbb, ctx->hs->tls13.transcript_hash, ctx->hs->tls13.transcript_hash_len)) goto err; if (!CBB_finish(&sig_cbb, &sig_content, &sig_content_len)) goto err; if ((mdctx = EVP_MD_CTX_new()) == NULL) goto err; if (!EVP_DigestSignInit(mdctx, &pctx, sigalg->md(), NULL, pkey)) goto err; if (sigalg->flags & SIGALG_FLAG_RSA_PSS) { if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING)) goto err; if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1)) goto err; } if (!EVP_DigestSignUpdate(mdctx, sig_content, sig_content_len)) goto err; if (EVP_DigestSignFinal(mdctx, NULL, &sig_len) <= 0) goto err; if ((sig = calloc(1, sig_len)) == NULL) goto err; if (EVP_DigestSignFinal(mdctx, sig, &sig_len) <= 0) goto err; if (!CBB_add_u16(cbb, sigalg->value)) goto err; if (!CBB_add_u16_length_prefixed(cbb, &sig_cbb)) goto err; if (!CBB_add_bytes(&sig_cbb, sig, sig_len)) goto err; if (!CBB_flush(cbb)) goto err; ret = 1; err: if (!ret && ctx->alert == 0) ctx->alert = TLS13_ALERT_INTERNAL_ERROR; CBB_cleanup(&sig_cbb); EVP_MD_CTX_free(mdctx); free(sig_content); free(sig); return ret; } int tls13_client_end_of_early_data_send(struct tls13_ctx *ctx, CBB *cbb) { return 0; } int tls13_client_finished_send(struct tls13_ctx *ctx, CBB *cbb) { struct tls13_secrets *secrets = ctx->hs->tls13.secrets; struct tls13_secret context = { .data = "", .len = 0 }; struct tls13_secret finished_key = { .data = NULL, .len = 0 }; uint8_t transcript_hash[EVP_MAX_MD_SIZE]; size_t transcript_hash_len; uint8_t *verify_data; size_t verify_data_len; unsigned int hlen; HMAC_CTX *hmac_ctx = NULL; CBS cbs; int ret = 0; if (!tls13_secret_init(&finished_key, EVP_MD_size(ctx->hash))) goto err; if (!tls13_hkdf_expand_label(&finished_key, ctx->hash, &secrets->client_handshake_traffic, "finished", &context)) goto err; if (!tls1_transcript_hash_value(ctx->ssl, transcript_hash, sizeof(transcript_hash), &transcript_hash_len)) goto err; if ((hmac_ctx = HMAC_CTX_new()) == NULL) goto err; if (!HMAC_Init_ex(hmac_ctx, finished_key.data, finished_key.len, ctx->hash, NULL)) goto err; if (!HMAC_Update(hmac_ctx, transcript_hash, transcript_hash_len)) goto err; verify_data_len = HMAC_size(hmac_ctx); if (!CBB_add_space(cbb, &verify_data, verify_data_len)) goto err; if (!HMAC_Final(hmac_ctx, verify_data, &hlen)) goto err; if (hlen != verify_data_len) goto err; CBS_init(&cbs, verify_data, verify_data_len); if (!CBS_write_bytes(&cbs, ctx->hs->finished, sizeof(ctx->hs->finished), &ctx->hs->finished_len)) goto err; ret = 1; err: tls13_secret_cleanup(&finished_key); HMAC_CTX_free(hmac_ctx); return ret; } int tls13_client_finished_sent(struct tls13_ctx *ctx) { struct tls13_secrets *secrets = ctx->hs->tls13.secrets; /* * Any records following the client finished message must be encrypted * using the client application traffic keys. */ return tls13_record_layer_set_write_traffic_key(ctx->rl, &secrets->client_application_traffic); }