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- /* Copyright (c) 2016, Google Inc.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
- * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
- * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
- * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
- #include <openssl/ssl.h>
- #include <assert.h>
- #include <string.h>
- #include <tuple>
- #include <openssl/aead.h>
- #include <openssl/bytestring.h>
- #include <openssl/digest.h>
- #include <openssl/err.h>
- #include <openssl/mem.h>
- #include <openssl/rand.h>
- #include <openssl/stack.h>
- #include "../crypto/internal.h"
- #include "internal.h"
- BSSL_NAMESPACE_BEGIN
- enum server_hs_state_t {
- state_select_parameters = 0,
- state_select_session,
- state_send_hello_retry_request,
- state_read_second_client_hello,
- state_send_server_hello,
- state_send_server_certificate_verify,
- state_send_server_finished,
- state_read_second_client_flight,
- state_process_end_of_early_data,
- state_read_client_certificate,
- state_read_client_certificate_verify,
- state_read_channel_id,
- state_read_client_finished,
- state_send_new_session_ticket,
- state_done,
- };
- static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
- // Allow a minute of ticket age skew in either direction. This covers
- // transmission delays in ClientHello and NewSessionTicket, as well as
- // drift between client and server clock rate since the ticket was issued.
- // See RFC 8446, section 8.3.
- static const int32_t kMaxTicketAgeSkewSeconds = 60;
- static int resolve_ecdhe_secret(SSL_HANDSHAKE *hs, bool *out_need_retry,
- SSL_CLIENT_HELLO *client_hello) {
- SSL *const ssl = hs->ssl;
- *out_need_retry = false;
- // We only support connections that include an ECDHE key exchange.
- CBS key_share;
- if (!ssl_client_hello_get_extension(client_hello, &key_share,
- TLSEXT_TYPE_key_share)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
- return 0;
- }
- bool found_key_share;
- Array<uint8_t> dhe_secret;
- uint8_t alert = SSL_AD_DECODE_ERROR;
- if (!ssl_ext_key_share_parse_clienthello(hs, &found_key_share, &dhe_secret,
- &alert, &key_share)) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
- return 0;
- }
- if (!found_key_share) {
- *out_need_retry = true;
- return 0;
- }
- return tls13_advance_key_schedule(hs, dhe_secret);
- }
- static int ssl_ext_supported_versions_add_serverhello(SSL_HANDSHAKE *hs,
- CBB *out) {
- CBB contents;
- if (!CBB_add_u16(out, TLSEXT_TYPE_supported_versions) ||
- !CBB_add_u16_length_prefixed(out, &contents) ||
- !CBB_add_u16(&contents, hs->ssl->version) ||
- !CBB_flush(out)) {
- return 0;
- }
- return 1;
- }
- static const SSL_CIPHER *choose_tls13_cipher(
- const SSL *ssl, const SSL_CLIENT_HELLO *client_hello, uint16_t group_id) {
- CBS cipher_suites;
- CBS_init(&cipher_suites, client_hello->cipher_suites,
- client_hello->cipher_suites_len);
- const uint16_t version = ssl_protocol_version(ssl);
- return ssl_choose_tls13_cipher(cipher_suites, version, group_id);
- }
- static bool add_new_session_tickets(SSL_HANDSHAKE *hs, bool *out_sent_tickets) {
- SSL *const ssl = hs->ssl;
- if (// If the client doesn't accept resumption with PSK_DHE_KE, don't send a
- // session ticket.
- !hs->accept_psk_mode ||
- // We only implement stateless resumption in TLS 1.3, so skip sending
- // tickets if disabled.
- (SSL_get_options(ssl) & SSL_OP_NO_TICKET)) {
- *out_sent_tickets = false;
- return true;
- }
- // TLS 1.3 recommends single-use tickets, so issue multiple tickets in case
- // the client makes several connections before getting a renewal.
- static const int kNumTickets = 2;
- // Rebase the session timestamp so that it is measured from ticket
- // issuance.
- ssl_session_rebase_time(ssl, hs->new_session.get());
- for (int i = 0; i < kNumTickets; i++) {
- UniquePtr<SSL_SESSION> session(
- SSL_SESSION_dup(hs->new_session.get(), SSL_SESSION_INCLUDE_NONAUTH));
- if (!session) {
- return false;
- }
- if (!RAND_bytes((uint8_t *)&session->ticket_age_add, 4)) {
- return false;
- }
- session->ticket_age_add_valid = true;
- if (ssl->enable_early_data) {
- // QUIC does not use the max_early_data_size parameter and always sets it
- // to a fixed value. See draft-ietf-quic-tls-22, section 4.5.
- session->ticket_max_early_data =
- ssl->quic_method != nullptr ? 0xffffffff : kMaxEarlyDataAccepted;
- }
- static_assert(kNumTickets < 256, "Too many tickets");
- uint8_t nonce[] = {static_cast<uint8_t>(i)};
- ScopedCBB cbb;
- CBB body, nonce_cbb, ticket, extensions;
- if (!ssl->method->init_message(ssl, cbb.get(), &body,
- SSL3_MT_NEW_SESSION_TICKET) ||
- !CBB_add_u32(&body, session->timeout) ||
- !CBB_add_u32(&body, session->ticket_age_add) ||
- !CBB_add_u8_length_prefixed(&body, &nonce_cbb) ||
- !CBB_add_bytes(&nonce_cbb, nonce, sizeof(nonce)) ||
- !CBB_add_u16_length_prefixed(&body, &ticket) ||
- !tls13_derive_session_psk(session.get(), nonce) ||
- !ssl_encrypt_ticket(hs, &ticket, session.get()) ||
- !CBB_add_u16_length_prefixed(&body, &extensions)) {
- return false;
- }
- if (ssl->enable_early_data) {
- CBB early_data_info;
- if (!CBB_add_u16(&extensions, TLSEXT_TYPE_early_data) ||
- !CBB_add_u16_length_prefixed(&extensions, &early_data_info) ||
- !CBB_add_u32(&early_data_info, session->ticket_max_early_data) ||
- !CBB_flush(&extensions)) {
- return false;
- }
- }
- // Add a fake extension. See draft-davidben-tls-grease-01.
- if (!CBB_add_u16(&extensions,
- ssl_get_grease_value(hs, ssl_grease_ticket_extension)) ||
- !CBB_add_u16(&extensions, 0 /* empty */)) {
- return false;
- }
- if (!ssl_add_message_cbb(ssl, cbb.get())) {
- return false;
- }
- }
- *out_sent_tickets = true;
- return true;
- }
- static enum ssl_hs_wait_t do_select_parameters(SSL_HANDSHAKE *hs) {
- // At this point, most ClientHello extensions have already been processed by
- // the common handshake logic. Resolve the remaining non-PSK parameters.
- SSL *const ssl = hs->ssl;
- SSLMessage msg;
- if (!ssl->method->get_message(ssl, &msg)) {
- return ssl_hs_read_message;
- }
- SSL_CLIENT_HELLO client_hello;
- if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
- OPENSSL_memcpy(hs->session_id, client_hello.session_id,
- client_hello.session_id_len);
- hs->session_id_len = client_hello.session_id_len;
- uint16_t group_id;
- if (!tls1_get_shared_group(hs, &group_id)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_GROUP);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
- return ssl_hs_error;
- }
- // Negotiate the cipher suite.
- hs->new_cipher = choose_tls13_cipher(ssl, &client_hello, group_id);
- if (hs->new_cipher == NULL) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_CIPHER);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
- return ssl_hs_error;
- }
- // HTTP/2 negotiation depends on the cipher suite, so ALPN negotiation was
- // deferred. Complete it now.
- uint8_t alert = SSL_AD_DECODE_ERROR;
- if (!ssl_negotiate_alpn(hs, &alert, &client_hello)) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
- return ssl_hs_error;
- }
- // The PRF hash is now known. Set up the key schedule and hash the
- // ClientHello.
- if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher)) {
- return ssl_hs_error;
- }
- hs->tls13_state = state_select_session;
- return ssl_hs_ok;
- }
- static enum ssl_ticket_aead_result_t select_session(
- SSL_HANDSHAKE *hs, uint8_t *out_alert, UniquePtr<SSL_SESSION> *out_session,
- int32_t *out_ticket_age_skew, bool *out_offered_ticket,
- const SSLMessage &msg, const SSL_CLIENT_HELLO *client_hello) {
- SSL *const ssl = hs->ssl;
- *out_session = nullptr;
- CBS pre_shared_key;
- *out_offered_ticket = ssl_client_hello_get_extension(
- client_hello, &pre_shared_key, TLSEXT_TYPE_pre_shared_key);
- if (!*out_offered_ticket) {
- return ssl_ticket_aead_ignore_ticket;
- }
- CBS ticket, binders;
- uint32_t client_ticket_age;
- if (!ssl_ext_pre_shared_key_parse_clienthello(
- hs, &ticket, &binders, &client_ticket_age, out_alert, client_hello,
- &pre_shared_key)) {
- return ssl_ticket_aead_error;
- }
- // If the peer did not offer psk_dhe, ignore the resumption.
- if (!hs->accept_psk_mode) {
- return ssl_ticket_aead_ignore_ticket;
- }
- // TLS 1.3 session tickets are renewed separately as part of the
- // NewSessionTicket.
- bool unused_renew;
- UniquePtr<SSL_SESSION> session;
- enum ssl_ticket_aead_result_t ret =
- ssl_process_ticket(hs, &session, &unused_renew, ticket, {});
- switch (ret) {
- case ssl_ticket_aead_success:
- break;
- case ssl_ticket_aead_error:
- *out_alert = SSL_AD_INTERNAL_ERROR;
- return ret;
- default:
- return ret;
- }
- if (!ssl_session_is_resumable(hs, session.get()) ||
- // Historically, some TLS 1.3 tickets were missing ticket_age_add.
- !session->ticket_age_add_valid) {
- return ssl_ticket_aead_ignore_ticket;
- }
- // Recover the client ticket age and convert to seconds.
- client_ticket_age -= session->ticket_age_add;
- client_ticket_age /= 1000;
- struct OPENSSL_timeval now;
- ssl_get_current_time(ssl, &now);
- // Compute the server ticket age in seconds.
- assert(now.tv_sec >= session->time);
- uint64_t server_ticket_age = now.tv_sec - session->time;
- // To avoid overflowing |hs->ticket_age_skew|, we will not resume
- // 68-year-old sessions.
- if (server_ticket_age > INT32_MAX) {
- return ssl_ticket_aead_ignore_ticket;
- }
- *out_ticket_age_skew = static_cast<int32_t>(client_ticket_age) -
- static_cast<int32_t>(server_ticket_age);
- // Check the PSK binder.
- if (!tls13_verify_psk_binder(hs, session.get(), msg, &binders)) {
- *out_alert = SSL_AD_DECRYPT_ERROR;
- return ssl_ticket_aead_error;
- }
- *out_session = std::move(session);
- return ssl_ticket_aead_success;
- }
- static enum ssl_hs_wait_t do_select_session(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- SSLMessage msg;
- if (!ssl->method->get_message(ssl, &msg)) {
- return ssl_hs_read_message;
- }
- SSL_CLIENT_HELLO client_hello;
- if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
- uint8_t alert = SSL_AD_DECODE_ERROR;
- UniquePtr<SSL_SESSION> session;
- bool offered_ticket = false;
- switch (select_session(hs, &alert, &session, &ssl->s3->ticket_age_skew,
- &offered_ticket, msg, &client_hello)) {
- case ssl_ticket_aead_ignore_ticket:
- assert(!session);
- if (!ssl->enable_early_data) {
- ssl->s3->early_data_reason = ssl_early_data_disabled;
- } else if (!offered_ticket) {
- ssl->s3->early_data_reason = ssl_early_data_no_session_offered;
- } else {
- ssl->s3->early_data_reason = ssl_early_data_session_not_resumed;
- }
- if (!ssl_get_new_session(hs, 1 /* server */)) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- break;
- case ssl_ticket_aead_success:
- // Carry over authentication information from the previous handshake into
- // a fresh session.
- hs->new_session =
- SSL_SESSION_dup(session.get(), SSL_SESSION_DUP_AUTH_ONLY);
- if (hs->new_session == nullptr) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- if (!ssl->enable_early_data) {
- ssl->s3->early_data_reason = ssl_early_data_disabled;
- } else if (session->ticket_max_early_data == 0) {
- ssl->s3->early_data_reason = ssl_early_data_unsupported_for_session;
- } else if (!hs->early_data_offered) {
- ssl->s3->early_data_reason = ssl_early_data_peer_declined;
- } else if (ssl->s3->channel_id_valid) {
- // Channel ID is incompatible with 0-RTT.
- ssl->s3->early_data_reason = ssl_early_data_channel_id;
- } else if (ssl->s3->token_binding_negotiated) {
- // Token Binding is incompatible with 0-RTT.
- ssl->s3->early_data_reason = ssl_early_data_token_binding;
- } else if (MakeConstSpan(ssl->s3->alpn_selected) != session->early_alpn) {
- // The negotiated ALPN must match the one in the ticket.
- ssl->s3->early_data_reason = ssl_early_data_alpn_mismatch;
- } else if (ssl->s3->ticket_age_skew < -kMaxTicketAgeSkewSeconds ||
- kMaxTicketAgeSkewSeconds < ssl->s3->ticket_age_skew) {
- ssl->s3->early_data_reason = ssl_early_data_ticket_age_skew;
- } else {
- ssl->s3->early_data_reason = ssl_early_data_accepted;
- ssl->s3->early_data_accepted = true;
- }
- ssl->s3->session_reused = true;
- // Resumption incorporates fresh key material, so refresh the timeout.
- ssl_session_renew_timeout(ssl, hs->new_session.get(),
- ssl->session_ctx->session_psk_dhe_timeout);
- break;
- case ssl_ticket_aead_error:
- ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
- return ssl_hs_error;
- case ssl_ticket_aead_retry:
- hs->tls13_state = state_select_session;
- return ssl_hs_pending_ticket;
- }
- // Record connection properties in the new session.
- hs->new_session->cipher = hs->new_cipher;
- // Store the initial negotiated ALPN in the session.
- if (!hs->new_session->early_alpn.CopyFrom(ssl->s3->alpn_selected)) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- if (ssl->ctx->dos_protection_cb != NULL &&
- ssl->ctx->dos_protection_cb(&client_hello) == 0) {
- // Connection rejected for DOS reasons.
- OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- size_t hash_len = EVP_MD_size(
- ssl_get_handshake_digest(ssl_protocol_version(ssl), hs->new_cipher));
- // Set up the key schedule and incorporate the PSK into the running secret.
- if (ssl->s3->session_reused) {
- if (!tls13_init_key_schedule(
- hs, MakeConstSpan(hs->new_session->master_key,
- hs->new_session->master_key_length))) {
- return ssl_hs_error;
- }
- } else if (!tls13_init_key_schedule(hs, MakeConstSpan(kZeroes, hash_len))) {
- return ssl_hs_error;
- }
- if (!ssl_hash_message(hs, msg)) {
- return ssl_hs_error;
- }
- if (ssl->s3->early_data_accepted) {
- if (!tls13_derive_early_secret(hs)) {
- return ssl_hs_error;
- }
- } else if (hs->early_data_offered) {
- ssl->s3->skip_early_data = true;
- }
- // Resolve ECDHE and incorporate it into the secret.
- bool need_retry;
- if (!resolve_ecdhe_secret(hs, &need_retry, &client_hello)) {
- if (need_retry) {
- if (ssl->s3->early_data_accepted) {
- ssl->s3->early_data_reason = ssl_early_data_hello_retry_request;
- ssl->s3->early_data_accepted = false;
- }
- ssl->s3->skip_early_data = true;
- ssl->method->next_message(ssl);
- if (!hs->transcript.UpdateForHelloRetryRequest()) {
- return ssl_hs_error;
- }
- hs->tls13_state = state_send_hello_retry_request;
- return ssl_hs_ok;
- }
- return ssl_hs_error;
- }
- // Note we defer releasing the early traffic secret to QUIC until after ECDHE
- // is resolved. The early traffic secret should be derived before the key
- // schedule incorporates ECDHE, but doing so may reject 0-RTT. To avoid
- // confusing the caller, we split derivation and releasing the secret to QUIC.
- if (ssl->s3->early_data_accepted &&
- !tls13_set_early_secret_for_quic(hs)) {
- return ssl_hs_error;
- }
- ssl->method->next_message(ssl);
- hs->tls13_state = state_send_server_hello;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_send_hello_retry_request(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- ScopedCBB cbb;
- CBB body, session_id, extensions;
- uint16_t group_id;
- if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_SERVER_HELLO) ||
- !CBB_add_u16(&body, TLS1_2_VERSION) ||
- !CBB_add_bytes(&body, kHelloRetryRequest, SSL3_RANDOM_SIZE) ||
- !CBB_add_u8_length_prefixed(&body, &session_id) ||
- !CBB_add_bytes(&session_id, hs->session_id, hs->session_id_len) ||
- !CBB_add_u16(&body, ssl_cipher_get_value(hs->new_cipher)) ||
- !CBB_add_u8(&body, 0 /* no compression */) ||
- !tls1_get_shared_group(hs, &group_id) ||
- !CBB_add_u16_length_prefixed(&body, &extensions) ||
- !CBB_add_u16(&extensions, TLSEXT_TYPE_supported_versions) ||
- !CBB_add_u16(&extensions, 2 /* length */) ||
- !CBB_add_u16(&extensions, ssl->version) ||
- !CBB_add_u16(&extensions, TLSEXT_TYPE_key_share) ||
- !CBB_add_u16(&extensions, 2 /* length */) ||
- !CBB_add_u16(&extensions, group_id) ||
- !ssl_add_message_cbb(ssl, cbb.get())) {
- return ssl_hs_error;
- }
- if (!ssl->method->add_change_cipher_spec(ssl)) {
- return ssl_hs_error;
- }
- hs->sent_hello_retry_request = true;
- hs->tls13_state = state_read_second_client_hello;
- return ssl_hs_flush;
- }
- static enum ssl_hs_wait_t do_read_second_client_hello(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_CLIENT_HELLO)) {
- return ssl_hs_error;
- }
- SSL_CLIENT_HELLO client_hello;
- if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
- // We perform all our negotiation based on the first ClientHello (for
- // consistency with what |select_certificate_cb| observed), which is in the
- // transcript, so we can ignore most of this second one.
- //
- // We do, however, check the second PSK binder. This covers the client key
- // share, in case we ever send half-RTT data (we currently do not). It is also
- // a tricky computation, so we enforce the peer handled it correctly.
- if (ssl->s3->session_reused) {
- CBS pre_shared_key;
- if (!ssl_client_hello_get_extension(&client_hello, &pre_shared_key,
- TLSEXT_TYPE_pre_shared_key)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_INCONSISTENT_CLIENT_HELLO);
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
- return ssl_hs_error;
- }
- CBS ticket, binders;
- uint32_t client_ticket_age;
- uint8_t alert = SSL_AD_DECODE_ERROR;
- if (!ssl_ext_pre_shared_key_parse_clienthello(
- hs, &ticket, &binders, &client_ticket_age, &alert, &client_hello,
- &pre_shared_key)) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
- return ssl_hs_error;
- }
- // Note it is important that we do not obtain a new |SSL_SESSION| from
- // |ticket|. We have already selected parameters based on the first
- // ClientHello (in the transcript) and must not switch partway through.
- if (!tls13_verify_psk_binder(hs, hs->new_session.get(), msg, &binders)) {
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
- return ssl_hs_error;
- }
- }
- bool need_retry;
- if (!resolve_ecdhe_secret(hs, &need_retry, &client_hello)) {
- if (need_retry) {
- // Only send one HelloRetryRequest.
- ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
- OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
- }
- return ssl_hs_error;
- }
- if (!ssl_hash_message(hs, msg)) {
- return ssl_hs_error;
- }
- ssl->method->next_message(ssl);
- hs->tls13_state = state_send_server_hello;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_send_server_hello(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- // Send a ServerHello.
- ScopedCBB cbb;
- CBB body, extensions, session_id;
- if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_SERVER_HELLO) ||
- !CBB_add_u16(&body, TLS1_2_VERSION) ||
- !RAND_bytes(ssl->s3->server_random, sizeof(ssl->s3->server_random)) ||
- !CBB_add_bytes(&body, ssl->s3->server_random, SSL3_RANDOM_SIZE) ||
- !CBB_add_u8_length_prefixed(&body, &session_id) ||
- !CBB_add_bytes(&session_id, hs->session_id, hs->session_id_len) ||
- !CBB_add_u16(&body, ssl_cipher_get_value(hs->new_cipher)) ||
- !CBB_add_u8(&body, 0) ||
- !CBB_add_u16_length_prefixed(&body, &extensions) ||
- !ssl_ext_pre_shared_key_add_serverhello(hs, &extensions) ||
- !ssl_ext_key_share_add_serverhello(hs, &extensions) ||
- !ssl_ext_supported_versions_add_serverhello(hs, &extensions) ||
- !ssl_add_message_cbb(ssl, cbb.get())) {
- return ssl_hs_error;
- }
- if (!hs->sent_hello_retry_request &&
- !ssl->method->add_change_cipher_spec(ssl)) {
- return ssl_hs_error;
- }
- // Derive and enable the handshake traffic secrets.
- if (!tls13_derive_handshake_secrets(hs) ||
- !tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal,
- hs->server_handshake_secret())) {
- return ssl_hs_error;
- }
- // Send EncryptedExtensions.
- if (!ssl->method->init_message(ssl, cbb.get(), &body,
- SSL3_MT_ENCRYPTED_EXTENSIONS) ||
- !ssl_add_serverhello_tlsext(hs, &body) ||
- !ssl_add_message_cbb(ssl, cbb.get())) {
- return ssl_hs_error;
- }
- if (!ssl->s3->session_reused) {
- // Determine whether to request a client certificate.
- hs->cert_request = !!(hs->config->verify_mode & SSL_VERIFY_PEER);
- // Only request a certificate if Channel ID isn't negotiated.
- if ((hs->config->verify_mode & SSL_VERIFY_PEER_IF_NO_OBC) &&
- ssl->s3->channel_id_valid) {
- hs->cert_request = false;
- }
- }
- // Send a CertificateRequest, if necessary.
- if (hs->cert_request) {
- CBB cert_request_extensions, sigalg_contents, sigalgs_cbb;
- if (!ssl->method->init_message(ssl, cbb.get(), &body,
- SSL3_MT_CERTIFICATE_REQUEST) ||
- !CBB_add_u8(&body, 0 /* no certificate_request_context. */) ||
- !CBB_add_u16_length_prefixed(&body, &cert_request_extensions) ||
- !CBB_add_u16(&cert_request_extensions,
- TLSEXT_TYPE_signature_algorithms) ||
- !CBB_add_u16_length_prefixed(&cert_request_extensions,
- &sigalg_contents) ||
- !CBB_add_u16_length_prefixed(&sigalg_contents, &sigalgs_cbb) ||
- !tls12_add_verify_sigalgs(ssl, &sigalgs_cbb,
- false /* online signature */)) {
- return ssl_hs_error;
- }
- if (tls12_has_different_verify_sigalgs_for_certs(ssl)) {
- if (!CBB_add_u16(&cert_request_extensions,
- TLSEXT_TYPE_signature_algorithms_cert) ||
- !CBB_add_u16_length_prefixed(&cert_request_extensions,
- &sigalg_contents) ||
- !CBB_add_u16_length_prefixed(&sigalg_contents, &sigalgs_cbb) ||
- !tls12_add_verify_sigalgs(ssl, &sigalgs_cbb, true /* certs */)) {
- return ssl_hs_error;
- }
- }
- if (ssl_has_client_CAs(hs->config)) {
- CBB ca_contents;
- if (!CBB_add_u16(&cert_request_extensions,
- TLSEXT_TYPE_certificate_authorities) ||
- !CBB_add_u16_length_prefixed(&cert_request_extensions,
- &ca_contents) ||
- !ssl_add_client_CA_list(hs, &ca_contents) ||
- !CBB_flush(&cert_request_extensions)) {
- return ssl_hs_error;
- }
- }
- if (!ssl_add_message_cbb(ssl, cbb.get())) {
- return ssl_hs_error;
- }
- }
- // Send the server Certificate message, if necessary.
- if (!ssl->s3->session_reused) {
- if (!ssl_has_certificate(hs)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET);
- return ssl_hs_error;
- }
- if (!tls13_add_certificate(hs)) {
- return ssl_hs_error;
- }
- hs->tls13_state = state_send_server_certificate_verify;
- return ssl_hs_ok;
- }
- hs->tls13_state = state_send_server_finished;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_send_server_certificate_verify(SSL_HANDSHAKE *hs) {
- switch (tls13_add_certificate_verify(hs)) {
- case ssl_private_key_success:
- hs->tls13_state = state_send_server_finished;
- return ssl_hs_ok;
- case ssl_private_key_retry:
- hs->tls13_state = state_send_server_certificate_verify;
- return ssl_hs_private_key_operation;
- case ssl_private_key_failure:
- return ssl_hs_error;
- }
- assert(0);
- return ssl_hs_error;
- }
- static enum ssl_hs_wait_t do_send_server_finished(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- if (!tls13_add_finished(hs) ||
- // Update the secret to the master secret and derive traffic keys.
- !tls13_advance_key_schedule(
- hs, MakeConstSpan(kZeroes, hs->transcript.DigestLen())) ||
- !tls13_derive_application_secrets(hs) ||
- !tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_seal,
- hs->server_traffic_secret_0())) {
- return ssl_hs_error;
- }
- if (ssl->s3->early_data_accepted) {
- // If accepting 0-RTT, we send tickets half-RTT. This gets the tickets on
- // the wire sooner and also avoids triggering a write on |SSL_read| when
- // processing the client Finished. This requires computing the client
- // Finished early. See RFC 8446, section 4.6.1.
- static const uint8_t kEndOfEarlyData[4] = {SSL3_MT_END_OF_EARLY_DATA, 0,
- 0, 0};
- if (ssl->quic_method == nullptr &&
- !hs->transcript.Update(kEndOfEarlyData)) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- size_t finished_len;
- if (!tls13_finished_mac(hs, hs->expected_client_finished().data(),
- &finished_len, false /* client */)) {
- return ssl_hs_error;
- }
- if (finished_len != hs->expected_client_finished().size()) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- // Feed the predicted Finished into the transcript. This allows us to derive
- // the resumption secret early and send half-RTT tickets.
- //
- // TODO(davidben): This will need to be updated for DTLS 1.3.
- assert(!SSL_is_dtls(hs->ssl));
- assert(hs->expected_client_finished().size() <= 0xff);
- uint8_t header[4] = {
- SSL3_MT_FINISHED, 0, 0,
- static_cast<uint8_t>(hs->expected_client_finished().size())};
- bool unused_sent_tickets;
- if (!hs->transcript.Update(header) ||
- !hs->transcript.Update(hs->expected_client_finished()) ||
- !tls13_derive_resumption_secret(hs) ||
- !add_new_session_tickets(hs, &unused_sent_tickets)) {
- return ssl_hs_error;
- }
- }
- hs->tls13_state = state_read_second_client_flight;
- return ssl_hs_flush;
- }
- static enum ssl_hs_wait_t do_read_second_client_flight(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- if (ssl->s3->early_data_accepted) {
- // QUIC never receives handshake messages under 0-RTT keys.
- if (ssl->quic_method == nullptr &&
- !tls13_set_traffic_key(ssl, ssl_encryption_early_data, evp_aead_open,
- hs->early_traffic_secret())) {
- return ssl_hs_error;
- }
- hs->can_early_write = true;
- hs->can_early_read = true;
- hs->in_early_data = true;
- }
- // QUIC doesn't use an EndOfEarlyData message (draft-ietf-quic-tls-22,
- // section 8.3), so we switch to client_handshake_secret before the early
- // return.
- if (ssl->quic_method != nullptr) {
- if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_open,
- hs->client_handshake_secret())) {
- return ssl_hs_error;
- }
- hs->tls13_state = state_read_client_certificate;
- return ssl->s3->early_data_accepted ? ssl_hs_early_return : ssl_hs_ok;
- }
- hs->tls13_state = state_process_end_of_early_data;
- return ssl->s3->early_data_accepted ? ssl_hs_read_end_of_early_data
- : ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_process_end_of_early_data(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- // If early data was not accepted, the EndOfEarlyData will be in the discarded
- // early data.
- if (hs->ssl->s3->early_data_accepted) {
- SSLMessage msg;
- if (!ssl->method->get_message(ssl, &msg)) {
- return ssl_hs_read_message;
- }
- if (!ssl_check_message_type(ssl, msg, SSL3_MT_END_OF_EARLY_DATA)) {
- return ssl_hs_error;
- }
- 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;
- }
- ssl->method->next_message(ssl);
- }
- if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_open,
- hs->client_handshake_secret())) {
- return ssl_hs_error;
- }
- hs->tls13_state = state_read_client_certificate;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_read_client_certificate(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- if (!hs->cert_request) {
- if (!ssl->s3->session_reused) {
- // 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. (Only do
- // this in full handshakes as resumptions should carry over the previous
- // |verify_result|, though this is a no-op because servers do not
- // implement the client's odd soft-fail mode.)
- hs->new_session->verify_result = X509_V_OK;
- }
- // Skip this state.
- hs->tls13_state = state_read_channel_id;
- return ssl_hs_ok;
- }
- const bool allow_anonymous =
- (hs->config->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) == 0;
- SSLMessage msg;
- if (!ssl->method->get_message(ssl, &msg)) {
- return ssl_hs_read_message;
- }
- if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE) ||
- !tls13_process_certificate(hs, msg, allow_anonymous) ||
- !ssl_hash_message(hs, msg)) {
- return ssl_hs_error;
- }
- ssl->method->next_message(ssl);
- hs->tls13_state = state_read_client_certificate_verify;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_read_client_certificate_verify(
- SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- if (sk_CRYPTO_BUFFER_num(hs->new_session->certs.get()) == 0) {
- // Skip this state.
- hs->tls13_state = state_read_channel_id;
- return ssl_hs_ok;
- }
- SSLMessage msg;
- if (!ssl->method->get_message(ssl, &msg)) {
- return ssl_hs_read_message;
- }
- switch (ssl_verify_peer_cert(hs)) {
- case ssl_verify_ok:
- break;
- case ssl_verify_invalid:
- return ssl_hs_error;
- case ssl_verify_retry:
- hs->tls13_state = state_read_client_certificate_verify;
- return ssl_hs_certificate_verify;
- }
- if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY) ||
- !tls13_process_certificate_verify(hs, msg) ||
- !ssl_hash_message(hs, msg)) {
- return ssl_hs_error;
- }
- ssl->method->next_message(ssl);
- hs->tls13_state = state_read_channel_id;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_read_channel_id(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- if (!ssl->s3->channel_id_valid) {
- hs->tls13_state = state_read_client_finished;
- 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_CHANNEL_ID) ||
- !tls1_verify_channel_id(hs, msg) ||
- !ssl_hash_message(hs, msg)) {
- return ssl_hs_error;
- }
- ssl->method->next_message(ssl);
- hs->tls13_state = state_read_client_finished;
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_read_client_finished(SSL_HANDSHAKE *hs) {
- SSL *const ssl = hs->ssl;
- SSLMessage msg;
- if (!ssl->method->get_message(ssl, &msg)) {
- return ssl_hs_read_message;
- }
- if (!ssl_check_message_type(ssl, msg, SSL3_MT_FINISHED) ||
- // If early data was accepted, we've already computed the client Finished
- // and derived the resumption secret.
- !tls13_process_finished(hs, msg, ssl->s3->early_data_accepted) ||
- // evp_aead_seal keys have already been switched.
- !tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_open,
- hs->client_traffic_secret_0())) {
- return ssl_hs_error;
- }
- if (!ssl->s3->early_data_accepted) {
- if (!ssl_hash_message(hs, msg) ||
- !tls13_derive_resumption_secret(hs)) {
- return ssl_hs_error;
- }
- // We send post-handshake tickets as part of the handshake in 1-RTT.
- hs->tls13_state = state_send_new_session_ticket;
- } else {
- // We already sent half-RTT tickets.
- hs->tls13_state = state_done;
- }
- ssl->method->next_message(ssl);
- return ssl_hs_ok;
- }
- static enum ssl_hs_wait_t do_send_new_session_ticket(SSL_HANDSHAKE *hs) {
- bool sent_tickets;
- if (!add_new_session_tickets(hs, &sent_tickets)) {
- return ssl_hs_error;
- }
- hs->tls13_state = state_done;
- // In TLS 1.3, the NewSessionTicket isn't flushed until the server performs a
- // write, to prevent a non-reading client from causing the server to hang in
- // the case of a small server write buffer. Consumers which don't write data
- // to the client will need to do a zero-byte write if they wish to flush the
- // tickets.
- if (hs->ssl->ctx->quic_method != nullptr && sent_tickets) {
- return ssl_hs_flush;
- }
- return ssl_hs_ok;
- }
- enum ssl_hs_wait_t tls13_server_handshake(SSL_HANDSHAKE *hs) {
- while (hs->tls13_state != state_done) {
- enum ssl_hs_wait_t ret = ssl_hs_error;
- enum server_hs_state_t state =
- static_cast<enum server_hs_state_t>(hs->tls13_state);
- switch (state) {
- case state_select_parameters:
- ret = do_select_parameters(hs);
- break;
- case state_select_session:
- ret = do_select_session(hs);
- break;
- case state_send_hello_retry_request:
- ret = do_send_hello_retry_request(hs);
- break;
- case state_read_second_client_hello:
- ret = do_read_second_client_hello(hs);
- break;
- case state_send_server_hello:
- ret = do_send_server_hello(hs);
- break;
- case state_send_server_certificate_verify:
- ret = do_send_server_certificate_verify(hs);
- break;
- case state_send_server_finished:
- ret = do_send_server_finished(hs);
- break;
- case state_read_second_client_flight:
- ret = do_read_second_client_flight(hs);
- break;
- case state_process_end_of_early_data:
- ret = do_process_end_of_early_data(hs);
- break;
- case state_read_client_certificate:
- ret = do_read_client_certificate(hs);
- break;
- case state_read_client_certificate_verify:
- ret = do_read_client_certificate_verify(hs);
- break;
- case state_read_channel_id:
- ret = do_read_channel_id(hs);
- break;
- case state_read_client_finished:
- ret = do_read_client_finished(hs);
- break;
- case state_send_new_session_ticket:
- ret = do_send_new_session_ticket(hs);
- break;
- case state_done:
- ret = ssl_hs_ok;
- break;
- }
- if (hs->tls13_state != state) {
- ssl_do_info_callback(hs->ssl, SSL_CB_ACCEPT_LOOP, 1);
- }
- if (ret != ssl_hs_ok) {
- return ret;
- }
- }
- return ssl_hs_ok;
- }
- const char *tls13_server_handshake_state(SSL_HANDSHAKE *hs) {
- enum server_hs_state_t state =
- static_cast<enum server_hs_state_t>(hs->tls13_state);
- switch (state) {
- case state_select_parameters:
- return "TLS 1.3 server select_parameters";
- case state_select_session:
- return "TLS 1.3 server select_session";
- case state_send_hello_retry_request:
- return "TLS 1.3 server send_hello_retry_request";
- case state_read_second_client_hello:
- return "TLS 1.3 server read_second_client_hello";
- case state_send_server_hello:
- return "TLS 1.3 server send_server_hello";
- case state_send_server_certificate_verify:
- return "TLS 1.3 server send_server_certificate_verify";
- case state_send_server_finished:
- return "TLS 1.3 server send_server_finished";
- case state_read_second_client_flight:
- return "TLS 1.3 server read_second_client_flight";
- case state_process_end_of_early_data:
- return "TLS 1.3 server process_end_of_early_data";
- case state_read_client_certificate:
- return "TLS 1.3 server read_client_certificate";
- case state_read_client_certificate_verify:
- return "TLS 1.3 server read_client_certificate_verify";
- case state_read_channel_id:
- return "TLS 1.3 server read_channel_id";
- case state_read_client_finished:
- return "TLS 1.3 server read_client_finished";
- case state_send_new_session_ticket:
- return "TLS 1.3 server send_new_session_ticket";
- case state_done:
- return "TLS 1.3 server done";
- }
- return "TLS 1.3 server unknown";
- }
- BSSL_NAMESPACE_END
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