| /* 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 |
| |
| 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; |
| bool enable_early_data = |
| ssl->enable_early_data && |
| (!ssl->quic_method || !ssl->config->quic_early_data_context.empty()); |
| if (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 (enable_early_data) { |
| CBB early_data; |
| if (!CBB_add_u16(&extensions, TLSEXT_TYPE_early_data) || |
| !CBB_add_u16_length_prefixed(&extensions, &early_data) || |
| !CBB_add_u32(&early_data, 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; |
| } |
| |
| if (ssl->quic_method != nullptr && client_hello.session_id_len > 0) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_COMPATIBILITY_MODE); |
| ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); |
| 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 = state13_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 bool quic_ticket_compatible(const SSL_SESSION *session, |
| const SSL_CONFIG *config) { |
| if (!session->is_quic) { |
| return true; |
| } |
| |
| if (session->quic_early_data_context.empty() || |
| config->quic_early_data_context.size() != |
| session->quic_early_data_context.size() || |
| CRYPTO_memcmp(config->quic_early_data_context.data(), |
| session->quic_early_data_context.data(), |
| session->quic_early_data_context.size()) != 0) { |
| return false; |
| } |
| return true; |
| } |
| |
| 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; |
| } |
| |
| // |ssl_session_is_resumable| forbids cross-cipher resumptions even if the |
| // PRF hashes match. |
| assert(hs->new_cipher == session->cipher); |
| |
| 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 if (!quic_ticket_compatible(session.get(), hs->config)) { |
| ssl->s3->early_data_reason = ssl_early_data_quic_parameter_mismatch; |
| } 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 = state13_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 = state13_send_hello_retry_request; |
| return ssl_hs_ok; |
| } |
| return ssl_hs_error; |
| } |
| |
| ssl->method->next_message(ssl); |
| hs->tls13_state = state13_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; |
| } |
| |
| ssl->s3->used_hello_retry_request = true; |
| hs->tls13_state = state13_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; |
| } |
| |
| // ClientHello should be the end of the flight. |
| if (ssl->method->has_unprocessed_handshake_data(ssl)) { |
| ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); |
| OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA); |
| return ssl_hs_error; |
| } |
| |
| ssl->method->next_message(ssl); |
| hs->tls13_state = state13_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 (!ssl->s3->used_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->new_session.get(), |
| 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(hs, &sigalgs_cbb)) { |
| 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 = state13_send_server_certificate_verify; |
| return ssl_hs_ok; |
| } |
| |
| hs->tls13_state = state13_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 = state13_send_server_finished; |
| return ssl_hs_ok; |
| |
| case ssl_private_key_retry: |
| hs->tls13_state = state13_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->new_session.get(), |
| hs->server_traffic_secret_0())) { |
| return ssl_hs_error; |
| } |
| |
| hs->tls13_state = state13_send_half_rtt_ticket; |
| return hs->handback ? ssl_hs_handback : ssl_hs_ok; |
| } |
| |
| static enum ssl_hs_wait_t do_send_half_rtt_ticket(SSL_HANDSHAKE *hs) { |
| SSL *const ssl = hs->ssl; |
| |
| 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 = state13_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) { |
| if (!tls13_set_traffic_key(ssl, ssl_encryption_early_data, evp_aead_open, |
| hs->new_session.get(), |
| 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->new_session.get(), |
| hs->client_handshake_secret())) { |
| return ssl_hs_error; |
| } |
| hs->tls13_state = state13_read_client_certificate; |
| return ssl->s3->early_data_accepted ? ssl_hs_early_return : ssl_hs_ok; |
| } |
| |
| hs->tls13_state = state13_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->new_session.get(), |
| hs->client_handshake_secret())) { |
| return ssl_hs_error; |
| } |
| hs->tls13_state = state13_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 = state13_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 = state13_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 = state13_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 = state13_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 = state13_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 = state13_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 = state13_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->new_session.get(), |
| 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 = state13_send_new_session_ticket; |
| } else { |
| // We already sent half-RTT tickets. |
| hs->tls13_state = state13_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 = state13_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->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 != state13_done) { |
| enum ssl_hs_wait_t ret = ssl_hs_error; |
| enum tls13_server_hs_state_t state = |
| static_cast<enum tls13_server_hs_state_t>(hs->tls13_state); |
| switch (state) { |
| case state13_select_parameters: |
| ret = do_select_parameters(hs); |
| break; |
| case state13_select_session: |
| ret = do_select_session(hs); |
| break; |
| case state13_send_hello_retry_request: |
| ret = do_send_hello_retry_request(hs); |
| break; |
| case state13_read_second_client_hello: |
| ret = do_read_second_client_hello(hs); |
| break; |
| case state13_send_server_hello: |
| ret = do_send_server_hello(hs); |
| break; |
| case state13_send_server_certificate_verify: |
| ret = do_send_server_certificate_verify(hs); |
| break; |
| case state13_send_server_finished: |
| ret = do_send_server_finished(hs); |
| break; |
| case state13_send_half_rtt_ticket: |
| ret = do_send_half_rtt_ticket(hs); |
| break; |
| case state13_read_second_client_flight: |
| ret = do_read_second_client_flight(hs); |
| break; |
| case state13_process_end_of_early_data: |
| ret = do_process_end_of_early_data(hs); |
| break; |
| case state13_read_client_certificate: |
| ret = do_read_client_certificate(hs); |
| break; |
| case state13_read_client_certificate_verify: |
| ret = do_read_client_certificate_verify(hs); |
| break; |
| case state13_read_channel_id: |
| ret = do_read_channel_id(hs); |
| break; |
| case state13_read_client_finished: |
| ret = do_read_client_finished(hs); |
| break; |
| case state13_send_new_session_ticket: |
| ret = do_send_new_session_ticket(hs); |
| break; |
| case state13_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 tls13_server_hs_state_t state = |
| static_cast<enum tls13_server_hs_state_t>(hs->tls13_state); |
| switch (state) { |
| case state13_select_parameters: |
| return "TLS 1.3 server select_parameters"; |
| case state13_select_session: |
| return "TLS 1.3 server select_session"; |
| case state13_send_hello_retry_request: |
| return "TLS 1.3 server send_hello_retry_request"; |
| case state13_read_second_client_hello: |
| return "TLS 1.3 server read_second_client_hello"; |
| case state13_send_server_hello: |
| return "TLS 1.3 server send_server_hello"; |
| case state13_send_server_certificate_verify: |
| return "TLS 1.3 server send_server_certificate_verify"; |
| case state13_send_half_rtt_ticket: |
| return "TLS 1.3 server send_half_rtt_ticket"; |
| case state13_send_server_finished: |
| return "TLS 1.3 server send_server_finished"; |
| case state13_read_second_client_flight: |
| return "TLS 1.3 server read_second_client_flight"; |
| case state13_process_end_of_early_data: |
| return "TLS 1.3 server process_end_of_early_data"; |
| case state13_read_client_certificate: |
| return "TLS 1.3 server read_client_certificate"; |
| case state13_read_client_certificate_verify: |
| return "TLS 1.3 server read_client_certificate_verify"; |
| case state13_read_channel_id: |
| return "TLS 1.3 server read_channel_id"; |
| case state13_read_client_finished: |
| return "TLS 1.3 server read_client_finished"; |
| case state13_send_new_session_ticket: |
| return "TLS 1.3 server send_new_session_ticket"; |
| case state13_done: |
| return "TLS 1.3 server done"; |
| } |
| |
| return "TLS 1.3 server unknown"; |
| } |
| |
| BSSL_NAMESPACE_END |
