|
- /* 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 <openssl/bytestring.h>
- #include <openssl/digest.h>
- #include <openssl/err.h>
- #include <openssl/mem.h>
- #include <openssl/rand.h>
- #include <openssl/stack.h>
-
- #include "internal.h"
-
-
- enum server_hs_state_t {
- state_process_client_hello = 0,
- state_send_server_hello,
- state_send_encrypted_extensions,
- state_send_certificate_request,
- state_send_server_certificate,
- state_send_server_certificate_verify,
- state_complete_server_certificate_verify,
- state_send_server_finished,
- state_flush,
- state_read_client_second_flight,
- state_process_client_certificate,
- state_process_client_certificate_verify,
- state_process_client_finished,
- state_done,
- };
-
- static enum ssl_hs_wait_t do_process_client_hello(SSL *ssl, SSL_HANDSHAKE *hs) {
- if (!tls13_check_message_type(ssl, SSL3_MT_CLIENT_HELLO)) {
- return ssl_hs_error;
- }
-
- struct ssl_early_callback_ctx early_ctx;
- uint16_t client_wire_version;
- CBS client_random, session_id, cipher_suites, compression_methods;
-
- memset(&early_ctx, 0, sizeof(early_ctx));
- early_ctx.ssl = ssl;
- early_ctx.client_hello = ssl->init_msg;
- early_ctx.client_hello_len = ssl->init_num;
- if (!ssl_early_callback_init(&early_ctx)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
-
- CBS cbs;
- CBS_init(&cbs, ssl->init_msg, ssl->init_num);
- if (!CBS_get_u16(&cbs, &client_wire_version) ||
- !CBS_get_bytes(&cbs, &client_random, SSL3_RANDOM_SIZE) ||
- !CBS_get_u8_length_prefixed(&cbs, &session_id) ||
- CBS_len(&session_id) > SSL_MAX_SSL_SESSION_ID_LENGTH) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
-
- uint16_t min_version, max_version;
- if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- return ssl_hs_error;
- }
-
- assert(ssl->s3->have_version);
-
- /* Load the client random. */
- memcpy(ssl->s3->client_random, CBS_data(&client_random), SSL3_RANDOM_SIZE);
-
- ssl->hit = 0;
- if (!ssl_get_new_session(ssl, 1 /* server */)) {
- ssl3_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(&early_ctx) == 0) {
- /* Connection rejected for DOS reasons. */
- OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ACCESS_DENIED);
- return ssl_hs_error;
- }
-
- if (!CBS_get_u16_length_prefixed(&cbs, &cipher_suites) ||
- CBS_len(&cipher_suites) == 0 ||
- CBS_len(&cipher_suites) % 2 != 0 ||
- !CBS_get_u8_length_prefixed(&cbs, &compression_methods) ||
- CBS_len(&compression_methods) == 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
-
- /* TLS 1.3 requires the peer only advertise the null compression. */
- if (CBS_len(&compression_methods) != 1 ||
- CBS_data(&compression_methods)[0] != 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_COMPRESSION_LIST);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
- return ssl_hs_error;
- }
-
- /* TLS extensions. */
- if (!ssl_parse_clienthello_tlsext(ssl, &cbs)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
- return ssl_hs_error;
- }
-
- /* There should be nothing left over in the message. */
- if (CBS_len(&cbs) != 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_PACKET_LENGTH);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return ssl_hs_error;
- }
-
- /* Let cert callback update server certificates if required.
- *
- * TODO(davidben): Can this get run earlier? */
- if (ssl->cert->cert_cb != NULL) {
- int rv = ssl->cert->cert_cb(ssl, ssl->cert->cert_cb_arg);
- if (rv == 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- return ssl_hs_error;
- }
- if (rv < 0) {
- hs->state = state_process_client_hello;
- return ssl_hs_x509_lookup;
- }
- }
-
- STACK_OF(SSL_CIPHER) *ciphers =
- ssl_bytes_to_cipher_list(ssl, &cipher_suites, max_version);
- if (ciphers == NULL) {
- return ssl_hs_error;
- }
-
- const SSL_CIPHER *cipher =
- ssl3_choose_cipher(ssl, ciphers, ssl_get_cipher_preferences(ssl));
- sk_SSL_CIPHER_free(ciphers);
- if (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;
- }
-
- ssl->session->cipher = cipher;
- ssl->s3->tmp.new_cipher = cipher;
-
- /* The PRF hash is now known. Set up the key schedule and hash the
- * ClientHello. */
- static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
- size_t hash_len =
- EVP_MD_size(ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl)));
- if (!tls13_init_key_schedule(ssl, kZeroes, hash_len)) {
- return ssl_hs_error;
- }
-
- /* Resolve PSK and incorporate it into the secret. */
- if (cipher->algorithm_auth == SSL_aPSK) {
- /* TODO(davidben): Support PSK. */
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return ssl_hs_error;
- } else if (!tls13_advance_key_schedule(ssl, kZeroes, hash_len)) {
- return ssl_hs_error;
- }
-
- /* Resolve ECDHE and incorporate it into the secret. */
- if (cipher->algorithm_mkey == SSL_kECDHE) {
- const uint8_t *key_share_buf = NULL;
- size_t key_share_len = 0;
- CBS key_share;
- if (!SSL_early_callback_ctx_extension_get(&early_ctx, TLSEXT_TYPE_key_share,
- &key_share_buf, &key_share_len)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
- return ssl_hs_error;
- }
-
- CBS_init(&key_share, key_share_buf, key_share_len);
- uint8_t *dhe_secret;
- size_t dhe_secret_len;
- uint8_t alert;
- if (!ext_key_share_parse_clienthello(ssl, &dhe_secret, &dhe_secret_len,
- &alert, &key_share)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
- return ssl_hs_error;
- }
-
- int ok = tls13_advance_key_schedule(ssl, dhe_secret, dhe_secret_len);
- OPENSSL_free(dhe_secret);
- if (!ok) {
- return ssl_hs_error;
- }
- } else if (!tls13_advance_key_schedule(ssl, kZeroes, hash_len)) {
- return ssl_hs_error;
- }
-
- hs->state = state_send_server_hello;
- return ssl_hs_ok;
- }
-
- static enum ssl_hs_wait_t do_send_server_hello(SSL *ssl, SSL_HANDSHAKE *hs) {
- CBB cbb, body, extensions;
- if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_SERVER_HELLO) ||
- !CBB_add_u16(&body, ssl->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_u16(&body, ssl_cipher_get_value(ssl->s3->tmp.new_cipher)) ||
- !CBB_add_u16_length_prefixed(&body, &extensions) ||
- !ext_key_share_add_serverhello(ssl, &extensions) ||
- !ssl->method->finish_message(ssl, &cbb)) {
- CBB_cleanup(&cbb);
- return ssl_hs_error;
- }
-
- hs->state = state_send_encrypted_extensions;
- return ssl_hs_write_message;
- }
-
- static enum ssl_hs_wait_t do_send_encrypted_extensions(SSL *ssl,
- SSL_HANDSHAKE *hs) {
- if (!tls13_set_handshake_traffic(ssl)) {
- return ssl_hs_error;
- }
-
- CBB cbb, body;
- if (!ssl->method->init_message(ssl, &cbb, &body,
- SSL3_MT_ENCRYPTED_EXTENSIONS) ||
- !ssl_add_serverhello_tlsext(ssl, &body) ||
- !ssl->method->finish_message(ssl, &cbb)) {
- CBB_cleanup(&cbb);
- return ssl_hs_error;
- }
-
- hs->state = state_send_certificate_request;
- return ssl_hs_write_message;
- }
-
- static enum ssl_hs_wait_t do_send_certificate_request(SSL *ssl,
- SSL_HANDSHAKE *hs) {
- /* Determine whether to request a client certificate. */
- ssl->s3->tmp.cert_request = !!(ssl->verify_mode & SSL_VERIFY_PEER);
- /* CertificateRequest may only be sent in certificate-based ciphers. */
- if (!ssl_cipher_uses_certificate_auth(ssl->s3->tmp.new_cipher)) {
- ssl->s3->tmp.cert_request = 0;
- }
-
- if (!ssl->s3->tmp.cert_request) {
- /* Skip this state. */
- hs->state = state_send_server_certificate;
- return ssl_hs_ok;
- }
-
- CBB cbb, body, sigalgs_cbb;
- if (!ssl->method->init_message(ssl, &cbb, &body,
- SSL3_MT_CERTIFICATE_REQUEST) ||
- !CBB_add_u8(&body, 0 /* no certificate_request_context. */)) {
- goto err;
- }
-
- const uint16_t *sigalgs;
- size_t sigalgs_len = tls12_get_psigalgs(ssl, &sigalgs);
- if (!CBB_add_u16_length_prefixed(&body, &sigalgs_cbb)) {
- goto err;
- }
-
- for (size_t i = 0; i < sigalgs_len; i++) {
- if (!CBB_add_u16(&sigalgs_cbb, sigalgs[i])) {
- goto err;
- }
- }
-
- if (!ssl_add_client_CA_list(ssl, &body) ||
- !CBB_add_u16(&body, 0 /* empty certificate_extensions. */) ||
- !ssl->method->finish_message(ssl, &cbb)) {
- goto err;
- }
-
- hs->state = state_send_server_certificate;
- return ssl_hs_write_message;
-
- err:
- CBB_cleanup(&cbb);
- return ssl_hs_error;
- }
-
- static enum ssl_hs_wait_t do_send_server_certificate(SSL *ssl,
- SSL_HANDSHAKE *hs) {
- if (!ssl_cipher_uses_certificate_auth(ssl->s3->tmp.new_cipher)) {
- hs->state = state_send_server_finished;
- return ssl_hs_ok;
- }
-
- if (!ssl_has_certificate(ssl)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET);
- return ssl_hs_error;
- }
-
- if (!tls13_prepare_certificate(ssl)) {
- return ssl_hs_error;
- }
-
- hs->state = state_send_server_certificate_verify;
- return ssl_hs_write_message;
- }
-
- static enum ssl_hs_wait_t do_send_server_certificate_verify(SSL *ssl,
- SSL_HANDSHAKE *hs,
- int is_first_run) {
- switch (tls13_prepare_certificate_verify(ssl, is_first_run)) {
- case ssl_private_key_success:
- hs->state = state_send_server_finished;
- return ssl_hs_write_message;
-
- case ssl_private_key_retry:
- hs->state = state_complete_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 *ssl, SSL_HANDSHAKE *hs) {
- if (!tls13_prepare_finished(ssl)) {
- return ssl_hs_error;
- }
-
- hs->state = state_flush;
- return ssl_hs_write_message;
- }
-
- static enum ssl_hs_wait_t do_flush(SSL *ssl, SSL_HANDSHAKE *hs) {
- hs->state = state_read_client_second_flight;
- return ssl_hs_flush;
- }
-
- static enum ssl_hs_wait_t do_read_client_second_flight(SSL *ssl,
- SSL_HANDSHAKE *hs) {
- /* Update the secret to the master secret and derive traffic keys. */
- static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
- if (!tls13_advance_key_schedule(ssl, kZeroes, hs->hash_len) ||
- !tls13_derive_traffic_secret_0(ssl) ||
- !tls13_set_traffic_key(ssl, type_data, evp_aead_seal,
- hs->traffic_secret_0, hs->hash_len)) {
- return ssl_hs_error;
- }
-
- hs->state = state_process_client_certificate;
- return ssl_hs_read_message;
- }
-
- static enum ssl_hs_wait_t do_process_client_certificate(SSL *ssl,
- SSL_HANDSHAKE *hs) {
- if (!ssl->s3->tmp.cert_request) {
- /* Skip this state. */
- hs->state = state_process_client_certificate_verify;
- return ssl_hs_ok;
- }
-
- if (!tls13_check_message_type(ssl, SSL3_MT_CERTIFICATE) ||
- !tls13_process_certificate(ssl) ||
- !ssl->method->hash_current_message(ssl)) {
- return ssl_hs_error;
- }
-
- hs->state = state_process_client_certificate_verify;
- return ssl_hs_read_message;
- }
-
- static enum ssl_hs_wait_t do_process_client_certificate_verify(
- SSL *ssl, SSL_HANDSHAKE *hs) {
- if (ssl->session->peer == NULL) {
- /* Skip this state. */
- hs->state = state_process_client_finished;
- return ssl_hs_ok;
- }
-
- if (!tls13_check_message_type(ssl, SSL3_MT_CERTIFICATE_VERIFY) ||
- !tls13_process_certificate_verify(ssl) ||
- !ssl->method->hash_current_message(ssl)) {
- return 0;
- }
-
- hs->state = state_process_client_finished;
- return ssl_hs_read_message;
- }
-
- static enum ssl_hs_wait_t do_process_client_finished(SSL *ssl,
- SSL_HANDSHAKE *hs) {
- if (!tls13_check_message_type(ssl, SSL3_MT_FINISHED) ||
- !tls13_process_finished(ssl) ||
- !ssl->method->hash_current_message(ssl) ||
- /* evp_aead_seal keys have already been switched. */
- !tls13_set_traffic_key(ssl, type_data, evp_aead_open,
- hs->traffic_secret_0, hs->hash_len) ||
- !tls13_finalize_keys(ssl)) {
- return ssl_hs_error;
- }
-
- hs->state = state_done;
- return ssl_hs_ok;
- }
-
- enum ssl_hs_wait_t tls13_server_handshake(SSL *ssl) {
- SSL_HANDSHAKE *hs = ssl->s3->hs;
-
- while (hs->state != state_done) {
- enum ssl_hs_wait_t ret = ssl_hs_error;
- enum server_hs_state_t state = hs->state;
- switch (state) {
- case state_process_client_hello:
- ret = do_process_client_hello(ssl, hs);
- break;
- case state_send_server_hello:
- ret = do_send_server_hello(ssl, hs);
- break;
- case state_send_encrypted_extensions:
- ret = do_send_encrypted_extensions(ssl, hs);
- break;
- case state_send_certificate_request:
- ret = do_send_certificate_request(ssl, hs);
- break;
- case state_send_server_certificate:
- ret = do_send_server_certificate(ssl, hs);
- break;
- case state_send_server_certificate_verify:
- ret = do_send_server_certificate_verify(ssl, hs, 1 /* first run */);
- break;
- case state_complete_server_certificate_verify:
- ret = do_send_server_certificate_verify(ssl, hs, 0 /* complete */);
- break;
- case state_send_server_finished:
- ret = do_send_server_finished(ssl, hs);
- break;
- case state_flush:
- ret = do_flush(ssl, hs);
- break;
- case state_read_client_second_flight:
- ret = do_read_client_second_flight(ssl, hs);
- break;
- case state_process_client_certificate:
- ret = do_process_client_certificate(ssl, hs);
- break;
- case state_process_client_certificate_verify:
- ret = do_process_client_certificate_verify(ssl, hs);
- break;
- case state_process_client_finished:
- ret = do_process_client_finished(ssl, hs);
- break;
- case state_done:
- ret = ssl_hs_ok;
- break;
- }
-
- if (ret != ssl_hs_ok) {
- return ret;
- }
- }
-
- return ssl_hs_ok;
- }
|