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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 <openssl/bytestring.h>
- #include <openssl/err.h>
- #include <openssl/hkdf.h>
- #include <openssl/mem.h>
- #include <openssl/stack.h>
- #include <openssl/x509.h>
- #include <openssl/x509v3.h>
-
- #include "internal.h"
-
-
- /* kMaxKeyUpdates is the number of consecutive KeyUpdates that will be
- * processed. Without this limit an attacker could force unbounded processing
- * without being able to return application data. */
- static const uint8_t kMaxKeyUpdates = 32;
-
- int tls13_handshake(SSL *ssl) {
- SSL_HANDSHAKE *hs = ssl->s3->hs;
-
- for (;;) {
- /* Resolve the operation the handshake was waiting on. */
- switch (hs->wait) {
- case ssl_hs_error:
- OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_HANDSHAKE_FAILURE);
- return -1;
-
- case ssl_hs_flush:
- case ssl_hs_flush_and_read_message: {
- int ret = BIO_flush(ssl->wbio);
- if (ret <= 0) {
- ssl->rwstate = SSL_WRITING;
- return ret;
- }
- if (hs->wait != ssl_hs_flush_and_read_message) {
- break;
- }
- ssl->method->expect_flight(ssl);
- hs->wait = ssl_hs_read_message;
- /* Fall-through. */
- }
-
- case ssl_hs_read_message: {
- int ret = ssl->method->ssl_get_message(ssl, -1, ssl_dont_hash_message);
- if (ret <= 0) {
- return ret;
- }
- break;
- }
-
- case ssl_hs_write_message: {
- int ret = ssl->method->write_message(ssl);
- if (ret <= 0) {
- return ret;
- }
- break;
- }
-
- case ssl_hs_x509_lookup:
- ssl->rwstate = SSL_X509_LOOKUP;
- hs->wait = ssl_hs_ok;
- return -1;
-
- case ssl_hs_private_key_operation:
- ssl->rwstate = SSL_PRIVATE_KEY_OPERATION;
- hs->wait = ssl_hs_ok;
- return -1;
-
- case ssl_hs_ok:
- break;
- }
-
- /* Run the state machine again. */
- hs->wait = hs->do_handshake(ssl);
- if (hs->wait == ssl_hs_error) {
- /* Don't loop around to avoid a stray |SSL_R_SSL_HANDSHAKE_FAILURE| the
- * first time around. */
- return -1;
- }
- if (hs->wait == ssl_hs_ok) {
- /* The handshake has completed. */
- return 1;
- }
-
- /* Otherwise, loop to the beginning and resolve what was blocking the
- * handshake. */
- }
- }
-
- static int tls13_get_cert_verify_signature_input(SSL *ssl, uint8_t **out,
- size_t *out_len, int server) {
- CBB cbb;
- if (!CBB_init(&cbb, 64 + 33 + 1 + 2 * EVP_MAX_MD_SIZE)) {
- goto err;
- }
-
- for (size_t i = 0; i < 64; i++) {
- if (!CBB_add_u8(&cbb, 0x20)) {
- goto err;
- }
- }
-
- if (server) {
- /* Include the NUL byte. */
- static const char kContext[] = "TLS 1.3, server CertificateVerify";
- if (!CBB_add_bytes(&cbb, (const uint8_t *)kContext, sizeof(kContext))) {
- goto err;
- }
- } else {
- static const char kContext[] = "TLS 1.3, client CertificateVerify";
- if (!CBB_add_bytes(&cbb, (const uint8_t *)kContext, sizeof(kContext))) {
- goto err;
- }
- }
-
- uint8_t context_hashes[2 * EVP_MAX_MD_SIZE];
- size_t context_hashes_len;
- if (!tls13_get_context_hashes(ssl, context_hashes, &context_hashes_len) ||
- !CBB_add_bytes(&cbb, context_hashes, context_hashes_len) ||
- !CBB_finish(&cbb, out, out_len)) {
- goto err;
- }
-
- return 1;
-
- err:
- OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
- CBB_cleanup(&cbb);
- return 0;
- }
-
- int tls13_process_certificate(SSL *ssl, int allow_anonymous) {
- CBS cbs, context;
- CBS_init(&cbs, ssl->init_msg, ssl->init_num);
- if (!CBS_get_u8_length_prefixed(&cbs, &context) ||
- CBS_len(&context) != 0) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- return 0;
- }
-
- const int retain_sha256 =
- ssl->server && ssl->ctx->retain_only_sha256_of_client_certs;
- int ret = 0;
- uint8_t alert;
- STACK_OF(X509) *chain = ssl_parse_cert_chain(
- ssl, &alert, retain_sha256 ? ssl->s3->new_session->peer_sha256 : NULL,
- &cbs);
- if (chain == NULL) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
- goto err;
- }
-
- if (CBS_len(&cbs) != 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- goto err;
- }
-
- if (sk_X509_num(chain) == 0) {
- if (!allow_anonymous) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
- goto err;
- }
-
- /* 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. */
- ssl->s3->new_session->verify_result = X509_V_OK;
-
- /* No certificate, so nothing more to do. */
- ret = 1;
- goto err;
- }
-
- ssl->s3->new_session->peer_sha256_valid = retain_sha256;
-
- if (!ssl_verify_cert_chain(ssl, &ssl->s3->new_session->verify_result,
- chain)) {
- goto err;
- }
-
- X509_free(ssl->s3->new_session->peer);
- X509 *leaf = sk_X509_value(chain, 0);
- X509_up_ref(leaf);
- ssl->s3->new_session->peer = leaf;
-
- sk_X509_pop_free(ssl->s3->new_session->cert_chain, X509_free);
- ssl->s3->new_session->cert_chain = chain;
- chain = NULL;
-
- ret = 1;
-
- err:
- sk_X509_pop_free(chain, X509_free);
- return ret;
- }
-
- int tls13_process_certificate_verify(SSL *ssl) {
- int ret = 0;
- X509 *peer = ssl->s3->new_session->peer;
- EVP_PKEY *pkey = NULL;
- uint8_t *msg = NULL;
- size_t msg_len;
-
- /* Filter out unsupported certificate types. */
- pkey = X509_get_pubkey(peer);
- if (pkey == NULL) {
- goto err;
- }
-
- CBS cbs, signature;
- uint16_t signature_algorithm;
- CBS_init(&cbs, ssl->init_msg, ssl->init_num);
- if (!CBS_get_u16(&cbs, &signature_algorithm) ||
- !CBS_get_u16_length_prefixed(&cbs, &signature) ||
- CBS_len(&cbs) != 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- goto err;
- }
-
- int al;
- if (!tls12_check_peer_sigalg(ssl, &al, signature_algorithm)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, al);
- goto err;
- }
- ssl->s3->tmp.peer_signature_algorithm = signature_algorithm;
-
- if (!tls13_get_cert_verify_signature_input(ssl, &msg, &msg_len,
- !ssl->server)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- goto err;
- }
-
- int sig_ok =
- ssl_public_key_verify(ssl, CBS_data(&signature), CBS_len(&signature),
- signature_algorithm, pkey, msg, msg_len);
- #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
- sig_ok = 1;
- ERR_clear_error();
- #endif
- if (!sig_ok) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
- goto err;
- }
-
- ret = 1;
-
- err:
- EVP_PKEY_free(pkey);
- OPENSSL_free(msg);
- return ret;
- }
-
- int tls13_check_message_type(SSL *ssl, int type) {
- if (ssl->s3->tmp.message_type != type) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
- OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
- ERR_add_error_dataf("got type %d, wanted type %d",
- ssl->s3->tmp.message_type, type);
- return 0;
- }
-
- return 1;
- }
-
- int tls13_process_finished(SSL *ssl) {
- uint8_t verify_data[EVP_MAX_MD_SIZE];
- size_t verify_data_len;
- if (!tls13_finished_mac(ssl, verify_data, &verify_data_len, !ssl->server)) {
- return 0;
- }
-
- int finished_ok =
- ssl->init_num == verify_data_len &&
- CRYPTO_memcmp(verify_data, ssl->init_msg, verify_data_len) == 0;
- #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
- finished_ok = 1;
- #endif
- if (!finished_ok) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
- OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED);
- return 0;
- }
-
- return 1;
- }
-
- int tls13_prepare_certificate(SSL *ssl) {
- CBB cbb, body;
- if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_CERTIFICATE) ||
- /* The request context is always empty in the handshake. */
- !CBB_add_u8(&body, 0) ||
- !ssl_add_cert_chain(ssl, &body) ||
- !ssl->method->finish_message(ssl, &cbb)) {
- CBB_cleanup(&cbb);
- return 0;
- }
-
- return 1;
- }
-
- enum ssl_private_key_result_t tls13_prepare_certificate_verify(
- SSL *ssl, int is_first_run) {
- enum ssl_private_key_result_t ret = ssl_private_key_failure;
- uint8_t *msg = NULL;
- size_t msg_len;
- CBB cbb, body;
- CBB_zero(&cbb);
-
- uint16_t signature_algorithm;
- if (!tls1_choose_signature_algorithm(ssl, &signature_algorithm)) {
- goto err;
- }
- if (!ssl->method->init_message(ssl, &cbb, &body,
- SSL3_MT_CERTIFICATE_VERIFY) ||
- !CBB_add_u16(&body, signature_algorithm)) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- /* Sign the digest. */
- CBB child;
- const size_t max_sig_len = ssl_private_key_max_signature_len(ssl);
- uint8_t *sig;
- size_t sig_len;
- if (!CBB_add_u16_length_prefixed(&body, &child) ||
- !CBB_reserve(&child, &sig, max_sig_len)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- goto err;
- }
-
- enum ssl_private_key_result_t sign_result;
- if (is_first_run) {
- if (!tls13_get_cert_verify_signature_input(ssl, &msg, &msg_len,
- ssl->server)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- goto err;
- }
- sign_result = ssl_private_key_sign(ssl, sig, &sig_len, max_sig_len,
- signature_algorithm, msg, msg_len);
- } else {
- sign_result = ssl_private_key_complete(ssl, sig, &sig_len, max_sig_len);
- }
-
- if (sign_result != ssl_private_key_success) {
- ret = sign_result;
- goto err;
- }
-
- if (!CBB_did_write(&child, sig_len) ||
- !ssl->method->finish_message(ssl, &cbb)) {
- goto err;
- }
-
- ret = ssl_private_key_success;
-
- err:
- CBB_cleanup(&cbb);
- OPENSSL_free(msg);
- return ret;
- }
-
- int tls13_prepare_finished(SSL *ssl) {
- size_t verify_data_len;
- uint8_t verify_data[EVP_MAX_MD_SIZE];
-
- if (!tls13_finished_mac(ssl, verify_data, &verify_data_len, ssl->server)) {
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
- OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED);
- return 0;
- }
-
- CBB cbb, body;
- if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_FINISHED) ||
- !CBB_add_bytes(&body, verify_data, verify_data_len) ||
- !ssl->method->finish_message(ssl, &cbb)) {
- CBB_cleanup(&cbb);
- return 0;
- }
-
- return 1;
- }
-
- static int tls13_receive_key_update(SSL *ssl) {
- if (ssl->init_num != 0) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
- return 0;
- }
-
- // TODO(svaldez): Send KeyUpdate.
- return tls13_rotate_traffic_key(ssl, evp_aead_open);
- }
-
- int tls13_post_handshake(SSL *ssl) {
- if (ssl->s3->tmp.message_type == SSL3_MT_KEY_UPDATE) {
- ssl->s3->key_update_count++;
- if (ssl->s3->key_update_count > kMaxKeyUpdates) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_KEY_UPDATES);
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
- return 0;
- }
-
- return tls13_receive_key_update(ssl);
- }
-
- ssl->s3->key_update_count = 0;
-
- if (ssl->s3->tmp.message_type == SSL3_MT_NEW_SESSION_TICKET &&
- !ssl->server) {
- return tls13_process_new_session_ticket(ssl);
- }
-
- // TODO(svaldez): Handle post-handshake authentication.
-
- ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
- OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
- return 0;
- }
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