blob: e634790a12c2a20a11b9b392ca68e05587a78cdf [file] [log] [blame]
/* 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;
}