Switch tls13_client and tls13_server to C++.
And, with that, stage one is complete. ssl/internal.h may include C++.
Bug: 132
Change-Id: I0cb89f0ed5f4be36632a50744a80321595dc921c
Reviewed-on: https://boringssl-review.googlesource.com/17768
Reviewed-by: Steven Valdez <svaldez@google.com>
diff --git a/ssl/tls13_server.cc b/ssl/tls13_server.cc
new file mode 100644
index 0000000..4e66016
--- /dev/null
+++ b/ssl/tls13_server.cc
@@ -0,0 +1,902 @@
+/* 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. */
+
+/* Per C99, various stdint.h macros are unavailable in C++ unless some macros
+ * are defined. C++11 overruled this decision, but older Android NDKs still
+ * require it. */
+#if !defined(__STDC_LIMIT_MACROS)
+#define __STDC_LIMIT_MACROS
+#endif
+
+#include <openssl/ssl.h>
+
+#include <assert.h>
+#include <string.h>
+
+#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"
+
+
+enum server_hs_state_t {
+ state_select_parameters = 0,
+ state_select_session,
+ state_send_hello_retry_request,
+ state_process_second_client_hello,
+ state_send_server_hello,
+ state_send_server_certificate_verify,
+ state_send_server_finished,
+ state_read_second_client_flight,
+ state_process_change_cipher_spec,
+ state_process_end_of_early_data,
+ state_process_client_certificate,
+ state_process_client_certificate_verify,
+ state_process_channel_id,
+ state_process_client_finished,
+ state_send_new_session_ticket,
+ state_done,
+};
+
+static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
+
+static int resolve_ecdhe_secret(SSL_HANDSHAKE *hs, int *out_need_retry,
+ SSL_CLIENT_HELLO *client_hello) {
+ SSL *const ssl = hs->ssl;
+ *out_need_retry = 0;
+
+ /* 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);
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
+ return 0;
+ }
+
+ int found_key_share;
+ uint8_t *dhe_secret;
+ size_t dhe_secret_len;
+ uint8_t alert = SSL_AD_DECODE_ERROR;
+ if (!ssl_ext_key_share_parse_clienthello(hs, &found_key_share, &dhe_secret,
+ &dhe_secret_len, &alert,
+ &key_share)) {
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
+ return 0;
+ }
+
+ if (!found_key_share) {
+ *out_need_retry = 1;
+ return 0;
+ }
+
+ int ok = tls13_advance_key_schedule(hs, dhe_secret, dhe_secret_len);
+ OPENSSL_free(dhe_secret);
+ return ok;
+}
+
+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) {
+ if (client_hello->cipher_suites_len % 2 != 0) {
+ return NULL;
+ }
+
+ CBS cipher_suites;
+ CBS_init(&cipher_suites, client_hello->cipher_suites,
+ client_hello->cipher_suites_len);
+
+ const int aes_is_fine = EVP_has_aes_hardware();
+ const uint16_t version = ssl3_protocol_version(ssl);
+
+ const SSL_CIPHER *best = NULL;
+ while (CBS_len(&cipher_suites) > 0) {
+ uint16_t cipher_suite;
+ if (!CBS_get_u16(&cipher_suites, &cipher_suite)) {
+ return NULL;
+ }
+
+ /* Limit to TLS 1.3 ciphers we know about. */
+ const SSL_CIPHER *candidate = SSL_get_cipher_by_value(cipher_suite);
+ if (candidate == NULL ||
+ SSL_CIPHER_get_min_version(candidate) > version ||
+ SSL_CIPHER_get_max_version(candidate) < version) {
+ continue;
+ }
+
+ /* TLS 1.3 removes legacy ciphers, so honor the client order, but prefer
+ * ChaCha20 if we do not have AES hardware. */
+ if (aes_is_fine) {
+ return candidate;
+ }
+
+ if (candidate->algorithm_enc == SSL_CHACHA20POLY1305) {
+ return candidate;
+ }
+
+ if (best == NULL) {
+ best = candidate;
+ }
+ }
+
+ return best;
+}
+
+static int add_new_session_tickets(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ /* 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;
+
+ SSL_SESSION *session = hs->new_session;
+ CBB cbb;
+ CBB_zero(&cbb);
+
+ /* Rebase the session timestamp so that it is measured from ticket
+ * issuance. */
+ ssl_session_rebase_time(ssl, session);
+
+ for (int i = 0; i < kNumTickets; i++) {
+ if (!RAND_bytes((uint8_t *)&session->ticket_age_add, 4)) {
+ goto err;
+ }
+ session->ticket_age_add_valid = 1;
+
+ CBB body, ticket, extensions;
+ if (!ssl->method->init_message(ssl, &cbb, &body,
+ SSL3_MT_NEW_SESSION_TICKET) ||
+ !CBB_add_u32(&body, session->timeout) ||
+ !CBB_add_u32(&body, session->ticket_age_add) ||
+ !CBB_add_u16_length_prefixed(&body, &ticket) ||
+ !ssl_encrypt_ticket(ssl, &ticket, session) ||
+ !CBB_add_u16_length_prefixed(&body, &extensions)) {
+ goto err;
+ }
+
+ if (ssl->cert->enable_early_data) {
+ session->ticket_max_early_data = kMaxEarlyDataAccepted;
+
+ CBB early_data_info;
+ if (!CBB_add_u16(&extensions, TLSEXT_TYPE_ticket_early_data_info) ||
+ !CBB_add_u16_length_prefixed(&extensions, &early_data_info) ||
+ !CBB_add_u32(&early_data_info, session->ticket_max_early_data) ||
+ !CBB_flush(&extensions)) {
+ goto err;
+ }
+ }
+
+ /* Add a fake extension. See draft-davidben-tls-grease-01. */
+ if (!CBB_add_u16(&extensions,
+ ssl_get_grease_value(ssl, ssl_grease_ticket_extension)) ||
+ !CBB_add_u16(&extensions, 0 /* empty */)) {
+ goto err;
+ }
+
+ if (!ssl_add_message_cbb(ssl, &cbb)) {
+ goto err;
+ }
+ }
+
+ return 1;
+
+err:
+ CBB_cleanup(&cbb);
+ return 0;
+}
+
+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;
+
+ SSL_CLIENT_HELLO client_hello;
+ if (!ssl_client_hello_init(ssl, &client_hello, ssl->init_msg,
+ ssl->init_num) ||
+ client_hello.session_id_len > sizeof(hs->session_id)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
+ ssl3_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;
+
+ /* Negotiate the cipher suite. */
+ hs->new_cipher = choose_tls13_cipher(ssl, &client_hello);
+ if (hs->new_cipher == NULL) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_CIPHER);
+ ssl3_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)) {
+ ssl3_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 (!tls13_init_key_schedule(hs) ||
+ !ssl_hash_current_message(hs)) {
+ 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, SSL_SESSION **out_session,
+ int32_t *out_ticket_age_skew, const SSL_CLIENT_HELLO *client_hello) {
+ SSL *const ssl = hs->ssl;
+ *out_session = NULL;
+
+ /* Decode the ticket if we agreed on a PSK key exchange mode. */
+ CBS pre_shared_key;
+ if (!hs->accept_psk_mode ||
+ !ssl_client_hello_get_extension(client_hello, &pre_shared_key,
+ TLSEXT_TYPE_pre_shared_key)) {
+ return ssl_ticket_aead_ignore_ticket;
+ }
+
+ /* Verify that the pre_shared_key extension is the last extension in
+ * ClientHello. */
+ if (CBS_data(&pre_shared_key) + CBS_len(&pre_shared_key) !=
+ client_hello->extensions + client_hello->extensions_len) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_PRE_SHARED_KEY_MUST_BE_LAST);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return ssl_ticket_aead_error;
+ }
+
+ CBS ticket, binders;
+ uint32_t client_ticket_age;
+ if (!ssl_ext_pre_shared_key_parse_clienthello(hs, &ticket, &binders,
+ &client_ticket_age, out_alert,
+ &pre_shared_key)) {
+ return ssl_ticket_aead_error;
+ }
+
+ /* TLS 1.3 session tickets are renewed separately as part of the
+ * NewSessionTicket. */
+ int unused_renew;
+ SSL_SESSION *session = NULL;
+ enum ssl_ticket_aead_result_t ret =
+ ssl_process_ticket(ssl, &session, &unused_renew, CBS_data(&ticket),
+ CBS_len(&ticket), NULL, 0);
+ 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) ||
+ /* Historically, some TLS 1.3 tickets were missing ticket_age_add. */
+ !session->ticket_age_add_valid) {
+ SSL_SESSION_free(session);
+ 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) {
+ SSL_SESSION_free(session);
+ return ssl_ticket_aead_ignore_ticket;
+ }
+
+ /* TODO(davidben,svaldez): Measure this value to decide on tolerance. For
+ * now, accept all values. https://crbug.com/boringssl/113. */
+ *out_ticket_age_skew =
+ (int32_t)client_ticket_age - (int32_t)server_ticket_age;
+
+ /* Check the PSK binder. */
+ if (!tls13_verify_psk_binder(hs, session, &binders)) {
+ SSL_SESSION_free(session);
+ *out_alert = SSL_AD_DECRYPT_ERROR;
+ return ssl_ticket_aead_error;
+ }
+
+ *out_session = session;
+ return ssl_ticket_aead_success;
+}
+
+static enum ssl_hs_wait_t do_select_session(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ SSL_CLIENT_HELLO client_hello;
+ if (!ssl_client_hello_init(ssl, &client_hello, ssl->init_msg,
+ ssl->init_num)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+ return ssl_hs_error;
+ }
+
+ uint8_t alert = SSL_AD_DECODE_ERROR;
+ SSL_SESSION *session = NULL;
+ switch (select_session(hs, &alert, &session, &ssl->s3->ticket_age_skew,
+ &client_hello)) {
+ case ssl_ticket_aead_ignore_ticket:
+ assert(session == NULL);
+ if (!ssl_get_new_session(hs, 1 /* server */)) {
+ ssl3_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, SSL_SESSION_DUP_AUTH_ONLY);
+
+ if (/* Early data must be acceptable for this ticket. */
+ ssl->cert->enable_early_data &&
+ session->ticket_max_early_data != 0 &&
+ /* The client must have offered early data. */
+ hs->early_data_offered &&
+ /* Channel ID is incompatible with 0-RTT. */
+ !ssl->s3->tlsext_channel_id_valid &&
+ /* The negotiated ALPN must match the one in the ticket. */
+ ssl->s3->alpn_selected_len == session->early_alpn_len &&
+ OPENSSL_memcmp(ssl->s3->alpn_selected, session->early_alpn,
+ ssl->s3->alpn_selected_len) == 0) {
+ ssl->early_data_accepted = 1;
+ }
+
+ SSL_SESSION_free(session);
+ if (hs->new_session == NULL) {
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+ return ssl_hs_error;
+ }
+
+ ssl->s3->session_reused = 1;
+
+ /* Resumption incorporates fresh key material, so refresh the timeout. */
+ ssl_session_renew_timeout(ssl, hs->new_session,
+ ssl->session_ctx->session_psk_dhe_timeout);
+ break;
+
+ case ssl_ticket_aead_error:
+ ssl3_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;
+
+ if (hs->hostname != NULL) {
+ OPENSSL_free(hs->new_session->tlsext_hostname);
+ hs->new_session->tlsext_hostname = BUF_strdup(hs->hostname);
+ if (hs->new_session->tlsext_hostname == NULL) {
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+ return ssl_hs_error;
+ }
+ }
+
+ /* Store the initial negotiated ALPN in the session. */
+ if (ssl->s3->alpn_selected != NULL) {
+ hs->new_session->early_alpn = (uint8_t *)BUF_memdup(
+ ssl->s3->alpn_selected, ssl->s3->alpn_selected_len);
+ if (hs->new_session->early_alpn == NULL) {
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+ return ssl_hs_error;
+ }
+ hs->new_session->early_alpn_len = ssl->s3->alpn_selected_len;
+ }
+
+ 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);
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+ return ssl_hs_error;
+ }
+
+ /* Incorporate the PSK into the running secret. */
+ if (ssl->s3->session_reused) {
+ if (!tls13_advance_key_schedule(hs, hs->new_session->master_key,
+ hs->new_session->master_key_length)) {
+ return ssl_hs_error;
+ }
+ } else if (!tls13_advance_key_schedule(hs, kZeroes, hs->hash_len)) {
+ return ssl_hs_error;
+ }
+
+ if (ssl->early_data_accepted) {
+ if (!tls13_derive_early_secrets(hs)) {
+ return ssl_hs_error;
+ }
+ } else if (hs->early_data_offered) {
+ ssl->s3->skip_early_data = 1;
+ }
+
+ ssl->method->received_flight(ssl);
+
+ /* Resolve ECDHE and incorporate it into the secret. */
+ int need_retry;
+ if (!resolve_ecdhe_secret(hs, &need_retry, &client_hello)) {
+ if (need_retry) {
+ ssl->early_data_accepted = 0;
+ ssl->s3->skip_early_data = 1;
+ hs->tls13_state = state_send_hello_retry_request;
+ return ssl_hs_ok;
+ }
+ return ssl_hs_error;
+ }
+
+ 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;
+ CBB cbb, body, extensions;
+ uint16_t group_id;
+ if (!ssl->method->init_message(ssl, &cbb, &body,
+ SSL3_MT_HELLO_RETRY_REQUEST) ||
+ !CBB_add_u16(&body, ssl->version) ||
+ !tls1_get_shared_group(hs, &group_id) ||
+ !CBB_add_u16_length_prefixed(&body, &extensions) ||
+ !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)) {
+ CBB_cleanup(&cbb);
+ return ssl_hs_error;
+ }
+
+ hs->tls13_state = state_process_second_client_hello;
+ return ssl_hs_flush_and_read_message;
+}
+
+static enum ssl_hs_wait_t do_process_second_client_hello(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl_check_message_type(ssl, SSL3_MT_CLIENT_HELLO)) {
+ return ssl_hs_error;
+ }
+
+ SSL_CLIENT_HELLO client_hello;
+ if (!ssl_client_hello_init(ssl, &client_hello, ssl->init_msg,
+ ssl->init_num)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
+ ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+ return ssl_hs_error;
+ }
+
+ int need_retry;
+ if (!resolve_ecdhe_secret(hs, &need_retry, &client_hello)) {
+ if (need_retry) {
+ /* Only send one HelloRetryRequest. */
+ ssl3_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_current_message(hs)) {
+ return ssl_hs_error;
+ }
+
+ ssl->method->received_flight(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;
+
+ uint16_t version = ssl->version;
+ if (ssl->version == TLS1_3_EXPERIMENT_VERSION) {
+ version = TLS1_2_VERSION;
+ }
+
+ /* Send a ServerHello. */
+ CBB cbb, body, extensions, session_id;
+ if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_SERVER_HELLO) ||
+ !CBB_add_u16(&body, version) ||
+ !RAND_bytes(ssl->s3->server_random, sizeof(ssl->s3->server_random)) ||
+ !CBB_add_bytes(&body, ssl->s3->server_random, SSL3_RANDOM_SIZE) ||
+ (ssl->version == TLS1_3_EXPERIMENT_VERSION &&
+ (!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)) ||
+ (ssl->version == TLS1_3_EXPERIMENT_VERSION && !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->version == TLS1_3_EXPERIMENT_VERSION &&
+ !ssl_ext_supported_versions_add_serverhello(hs, &extensions)) ||
+ !ssl_add_message_cbb(ssl, &cbb)) {
+ goto err;
+ }
+
+ if (ssl->version == TLS1_3_EXPERIMENT_VERSION &&
+ !ssl3_add_change_cipher_spec(ssl)) {
+ goto err;
+ }
+
+ /* Derive and enable the handshake traffic secrets. */
+ if (!tls13_derive_handshake_secrets(hs) ||
+ !tls13_set_traffic_key(ssl, evp_aead_seal, hs->server_handshake_secret,
+ hs->hash_len)) {
+ goto err;
+ }
+
+ /* Send EncryptedExtensions. */
+ if (!ssl->method->init_message(ssl, &cbb, &body,
+ SSL3_MT_ENCRYPTED_EXTENSIONS) ||
+ !ssl_add_serverhello_tlsext(hs, &body) ||
+ !ssl_add_message_cbb(ssl, &cbb)) {
+ goto err;
+ }
+
+ if (!ssl->s3->session_reused) {
+ /* Determine whether to request a client certificate. */
+ hs->cert_request = !!(ssl->verify_mode & SSL_VERIFY_PEER);
+ /* Only request a certificate if Channel ID isn't negotiated. */
+ if ((ssl->verify_mode & SSL_VERIFY_PEER_IF_NO_OBC) &&
+ ssl->s3->tlsext_channel_id_valid) {
+ hs->cert_request = 0;
+ }
+ }
+
+ /* Send a CertificateRequest, if necessary. */
+ if (hs->cert_request) {
+ CBB sigalgs_cbb;
+ if (!ssl->method->init_message(ssl, &cbb, &body,
+ SSL3_MT_CERTIFICATE_REQUEST) ||
+ !CBB_add_u8(&body, 0 /* no certificate_request_context. */) ||
+ !CBB_add_u16_length_prefixed(&body, &sigalgs_cbb) ||
+ !tls12_add_verify_sigalgs(ssl, &sigalgs_cbb) ||
+ !ssl_add_client_CA_list(ssl, &body) ||
+ !CBB_add_u16(&body, 0 /* empty certificate_extensions. */) ||
+ !ssl_add_message_cbb(ssl, &cbb)) {
+ goto err;
+ }
+ }
+
+ /* Send the server Certificate message, if necessary. */
+ if (!ssl->s3->session_reused) {
+ if (!ssl_has_certificate(ssl)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET);
+ goto err;
+ }
+
+ if (!tls13_add_certificate(hs)) {
+ goto err;
+ }
+
+ hs->tls13_state = state_send_server_certificate_verify;
+ return ssl_hs_ok;
+ }
+
+ hs->tls13_state = state_send_server_finished;
+ return ssl_hs_ok;
+
+err:
+ CBB_cleanup(&cbb);
+ return ssl_hs_error;
+}
+
+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, kZeroes, hs->hash_len) ||
+ !tls13_derive_application_secrets(hs) ||
+ !tls13_set_traffic_key(ssl, evp_aead_seal, hs->server_traffic_secret_0,
+ hs->hash_len)) {
+ return ssl_hs_error;
+ }
+
+ if (ssl->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 draft-ietf-tls-tls13-18, section 4.5.1. */
+ size_t finished_len;
+ if (!tls13_finished_mac(hs, hs->expected_client_finished, &finished_len,
+ 0 /* client */)) {
+ return ssl_hs_error;
+ }
+
+ if (finished_len != hs->hash_len) {
+ 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->hash_len <= 0xff);
+ uint8_t header[4] = {SSL3_MT_FINISHED, 0, 0, static_cast<uint8_t>(hs->hash_len)};
+ if (!SSL_TRANSCRIPT_update(&hs->transcript, header, sizeof(header)) ||
+ !SSL_TRANSCRIPT_update(&hs->transcript, hs->expected_client_finished,
+ hs->hash_len) ||
+ !tls13_derive_resumption_secret(hs) ||
+ !add_new_session_tickets(hs)) {
+ 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->early_data_accepted) {
+ if (!tls13_set_traffic_key(ssl, evp_aead_open, hs->early_traffic_secret,
+ hs->hash_len)) {
+ return ssl_hs_error;
+ }
+ hs->can_early_write = 1;
+ hs->can_early_read = 1;
+ hs->in_early_data = 1;
+ hs->tls13_state = state_process_end_of_early_data;
+ return ssl_hs_read_end_of_early_data;
+ }
+ hs->tls13_state = state_process_end_of_early_data;
+ return ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_process_end_of_early_data(SSL_HANDSHAKE *hs) {
+ hs->tls13_state = state_process_change_cipher_spec;
+ /* If early data was accepted, the ChangeCipherSpec message will be in the
+ * discarded early data. */
+ if (hs->early_data_offered && !hs->ssl->early_data_accepted) {
+ return ssl_hs_ok;
+ }
+ return hs->ssl->version == TLS1_3_EXPERIMENT_VERSION
+ ? ssl_hs_read_change_cipher_spec
+ : ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ if (!tls13_set_traffic_key(ssl, evp_aead_open, hs->client_handshake_secret,
+ hs->hash_len)) {
+ return ssl_hs_error;
+ }
+ hs->tls13_state = ssl->early_data_accepted ? state_process_client_finished
+ : state_process_client_certificate;
+ return ssl_hs_read_message;
+}
+
+static enum ssl_hs_wait_t do_process_client_certificate(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ if (!hs->cert_request) {
+ /* OpenSSL returns X509_V_OK when no certificates are requested. This is
+ * classed by them as a bug, but it's assumed by at least NGINX. */
+ hs->new_session->verify_result = X509_V_OK;
+
+ /* Skip this state. */
+ hs->tls13_state = state_process_channel_id;
+ return ssl_hs_ok;
+ }
+
+ const int allow_anonymous =
+ (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) == 0;
+
+ if (!ssl_check_message_type(ssl, SSL3_MT_CERTIFICATE) ||
+ !tls13_process_certificate(hs, allow_anonymous) ||
+ !ssl_hash_current_message(hs)) {
+ return ssl_hs_error;
+ }
+
+ hs->tls13_state = state_process_client_certificate_verify;
+ return ssl_hs_read_message;
+}
+
+static enum ssl_hs_wait_t do_process_client_certificate_verify(
+ SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) == 0) {
+ /* Skip this state. */
+ hs->tls13_state = state_process_channel_id;
+ return ssl_hs_ok;
+ }
+
+ if (!ssl_check_message_type(ssl, SSL3_MT_CERTIFICATE_VERIFY) ||
+ !tls13_process_certificate_verify(hs) ||
+ !ssl_hash_current_message(hs)) {
+ return ssl_hs_error;
+ }
+
+ hs->tls13_state = state_process_channel_id;
+ return ssl_hs_read_message;
+}
+
+static enum ssl_hs_wait_t do_process_channel_id(SSL_HANDSHAKE *hs) {
+ if (!hs->ssl->s3->tlsext_channel_id_valid) {
+ hs->tls13_state = state_process_client_finished;
+ return ssl_hs_ok;
+ }
+
+ if (!ssl_check_message_type(hs->ssl, SSL3_MT_CHANNEL_ID) ||
+ !tls1_verify_channel_id(hs) ||
+ !ssl_hash_current_message(hs)) {
+ return ssl_hs_error;
+ }
+
+ hs->tls13_state = state_process_client_finished;
+ return ssl_hs_read_message;
+}
+
+static enum ssl_hs_wait_t do_process_client_finished(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl_check_message_type(ssl, SSL3_MT_FINISHED) ||
+ /* If early data was accepted, we've already computed the client Finished
+ * and derived the resumption secret. */
+ !tls13_process_finished(hs, ssl->early_data_accepted) ||
+ /* evp_aead_seal keys have already been switched. */
+ !tls13_set_traffic_key(ssl, evp_aead_open, hs->client_traffic_secret_0,
+ hs->hash_len)) {
+ return ssl_hs_error;
+ }
+
+ ssl->method->received_flight(ssl);
+
+ if (!ssl->early_data_accepted) {
+ if (!ssl_hash_current_message(hs) ||
+ !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;
+ return ssl_hs_ok;
+ }
+
+ hs->tls13_state = state_done;
+ return ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_send_new_session_ticket(SSL_HANDSHAKE *hs) {
+ /* If the client doesn't accept resumption with PSK_DHE_KE, don't send a
+ * session ticket. */
+ if (!hs->accept_psk_mode) {
+ hs->tls13_state = state_done;
+ return ssl_hs_ok;
+ }
+
+ if (!add_new_session_tickets(hs)) {
+ return ssl_hs_error;
+ }
+
+ hs->tls13_state = state_done;
+ return ssl_hs_flush;
+}
+
+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_process_second_client_hello:
+ ret = do_process_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_process_change_cipher_spec:
+ ret = do_process_change_cipher_spec(hs);
+ break;
+ case state_process_client_certificate:
+ ret = do_process_client_certificate(hs);
+ break;
+ case state_process_client_certificate_verify:
+ ret = do_process_client_certificate_verify(hs);
+ break;
+ case state_process_channel_id:
+ ret = do_process_channel_id(hs);
+ break;
+ case state_process_client_finished:
+ ret = do_process_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 (ret != ssl_hs_ok) {
+ return ret;
+ }
+ }
+
+ return ssl_hs_ok;
+}
