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cli/vendor/aws-lc-sys/aws-lc/ssl/handshake_client.cc

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// Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
// Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved.
// Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
// Copyright 2005 Nokia. All rights reserved.
//
// ECC cipher suite support in OpenSSL originally written by
// Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories.
//
// The Contribution, originally written by Mika Kousa and Pasi Eronen of
// Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
// support (see RFC 4279) to OpenSSL.
//
// SPDX-License-Identifier: Apache-2.0
#include <openssl/ssl.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include <utility>
#include <openssl/aead.h>
#include <openssl/bn.h>
#include <openssl/bytestring.h>
#include <openssl/ec_key.h>
#include <openssl/ecdsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/hpke.h>
#include <openssl/md5.h>
#include <openssl/mem.h>
#include <openssl/rand.h>
#include <openssl/sha.h>
#include "../crypto/internal.h"
#include "internal.h"
BSSL_NAMESPACE_BEGIN
enum ssl_client_hs_state_t {
state_start_connect = 0,
state_enter_early_data,
state_early_reverify_server_certificate,
state_read_hello_verify_request,
state_read_server_hello,
state_tls13,
state_read_server_certificate,
state_read_certificate_status,
state_verify_server_certificate,
state_reverify_server_certificate,
state_read_server_key_exchange,
state_read_certificate_request,
state_read_server_hello_done,
state_send_client_certificate,
state_send_client_key_exchange,
state_send_client_certificate_verify,
state_send_client_finished,
state_finish_flight,
state_read_session_ticket,
state_process_change_cipher_spec,
state_read_server_finished,
state_finish_client_handshake,
state_done,
};
// ssl_get_client_disabled sets |*out_mask_a| and |*out_mask_k| to masks of
// disabled algorithms.
static void ssl_get_client_disabled(const SSL_HANDSHAKE *hs,
uint32_t *out_mask_a,
uint32_t *out_mask_k) {
*out_mask_a = 0;
*out_mask_k = 0;
// PSK requires a client callback.
if (hs->config->psk_client_callback == NULL) {
*out_mask_a |= SSL_aPSK;
*out_mask_k |= SSL_kPSK;
}
}
// collect_cipher_protocol_ids uses |cbb| to collect IANA-assigned numbers
// of |ciphers|. |mask_a|, |mask_k|, |max_version| and |min_version|
// are used to filter the |ciphers|. |any_enabled| will be true if not all
// ciphers are filtered out.
// It returns true when success. It returns false otherwise.
static bool collect_cipher_protocol_ids(STACK_OF(SSL_CIPHER) *ciphers,
CBB *cbb, uint32_t mask_k, uint32_t mask_a, uint16_t max_version,
uint16_t min_version, bool *any_enabled) {
*any_enabled = false;
for (const SSL_CIPHER *cipher : ciphers) {
// Skip disabled ciphers
if ((cipher->algorithm_mkey & mask_k) ||
(cipher->algorithm_auth & mask_a)) {
continue;
}
if (SSL_CIPHER_get_min_version(cipher) > max_version ||
SSL_CIPHER_get_max_version(cipher) < min_version) {
continue;
}
*any_enabled = true;
if (!CBB_add_u16(cbb, SSL_CIPHER_get_protocol_id(cipher))) {
return false;
}
}
return true;
}
static bool ssl_write_client_cipher_list(const SSL_HANDSHAKE *hs, CBB *out,
ssl_client_hello_type_t type) {
const SSL *const ssl = hs->ssl;
uint32_t mask_a, mask_k;
ssl_get_client_disabled(hs, &mask_a, &mask_k);
CBB child;
if (!CBB_add_u16_length_prefixed(out, &child)) {
return false;
}
// Add a fake cipher suite. See RFC 8701.
if (ssl->ctx->grease_enabled &&
!CBB_add_u16(&child, ssl_get_grease_value(hs, ssl_grease_cipher))) {
return false;
}
// Add all ciphers unless TLS 1.3 only connection
if (hs->min_version < TLS1_3_VERSION && type != ssl_client_hello_inner) {
bool any_enabled = false;
if (!collect_cipher_protocol_ids(SSL_get_ciphers(ssl), &child, mask_k,
mask_a, hs->max_version, hs->min_version, &any_enabled)) {
return false;
}
// If all ciphers were disabled, return the error to the caller.
if (!any_enabled) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CIPHERS_AVAILABLE);
return false;
}
} else if (hs->max_version >= TLS1_3_VERSION) {
// Only TLS 1.3 ciphers
STACK_OF(SSL_CIPHER) *ciphers = (ssl->config && ssl->config->tls13_cipher_list) ?
ssl->config->tls13_cipher_list->ciphers.get() : ssl->ctx->tls13_cipher_list->ciphers.get();
bool any_enabled = false;
if (!collect_cipher_protocol_ids(ciphers, &child, mask_k,
mask_a, hs->max_version, hs->min_version, &any_enabled)) {
return false;
}
// If all ciphers were disabled, return the error to the caller.
if (!any_enabled) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CIPHERS_AVAILABLE);
return false;
}
}
if (ssl->mode & SSL_MODE_SEND_FALLBACK_SCSV) {
if (!CBB_add_u16(&child, SSL3_CK_FALLBACK_SCSV & 0xffff)) {
return false;
}
}
return CBB_flush(out);
}
bool ssl_write_client_hello_without_extensions(const SSL_HANDSHAKE *hs,
CBB *cbb,
ssl_client_hello_type_t type,
bool empty_session_id) {
const SSL *const ssl = hs->ssl;
CBB child;
if (!CBB_add_u16(cbb, hs->client_version) ||
!CBB_add_bytes(cbb,
type == ssl_client_hello_inner ? hs->inner_client_random
: ssl->s3->client_random,
SSL3_RANDOM_SIZE) ||
!CBB_add_u8_length_prefixed(cbb, &child)) {
return false;
}
// Do not send a session ID on renegotiation.
if (!ssl->s3->initial_handshake_complete &&
!empty_session_id &&
!CBB_add_bytes(&child, hs->session_id, hs->session_id_len)) {
return false;
}
if (SSL_is_dtls(ssl)) {
if (!CBB_add_u8_length_prefixed(cbb, &child) ||
!CBB_add_bytes(&child, hs->dtls_cookie.data(),
hs->dtls_cookie.size())) {
return false;
}
}
if (!ssl_write_client_cipher_list(hs, cbb, type) ||
!CBB_add_u8(cbb, 1 /* one compression method */) ||
!CBB_add_u8(cbb, 0 /* null compression */)) {
return false;
}
return true;
}
bool ssl_add_client_hello(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ScopedCBB cbb;
CBB body;
ssl_client_hello_type_t type = hs->selected_ech_config
? ssl_client_hello_outer
: ssl_client_hello_unencrypted;
bool needs_psk_binder;
Array<uint8_t> msg;
if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CLIENT_HELLO) ||
!ssl_write_client_hello_without_extensions(hs, &body, type,
/*empty_session_id=*/false) ||
!ssl_add_clienthello_tlsext(hs, &body, /*out_encoded=*/nullptr,
&needs_psk_binder, type, CBB_len(&body)) ||
!ssl->method->finish_message(ssl, cbb.get(), &msg)) {
return false;
}
// Now that the length prefixes have been computed, fill in the placeholder
// PSK binder.
if (needs_psk_binder) {
// ClientHelloOuter cannot have a PSK binder. Otherwise the
// ClientHellOuterAAD computation would break.
assert(type != ssl_client_hello_outer);
if (!tls13_write_psk_binder(hs, hs->transcript, MakeSpan(msg),
/*out_binder_len=*/0)) {
return false;
}
}
return ssl->method->add_message(ssl, std::move(msg));
}
static bool parse_server_version(const SSL_HANDSHAKE *hs, uint16_t *out_version,
uint8_t *out_alert,
const ParsedServerHello &server_hello) {
// If the outer version is not TLS 1.2, use it.
// TODO(davidben): This function doesn't quite match the RFC8446 formulation.
if (server_hello.legacy_version != TLS1_2_VERSION) {
*out_version = server_hello.legacy_version;
return true;
}
SSLExtension supported_versions(TLSEXT_TYPE_supported_versions);
CBS extensions = server_hello.extensions;
if (!ssl_parse_extensions(&extensions, out_alert, {&supported_versions},
/*ignore_unknown=*/true)) {
return false;
}
if (!supported_versions.present) {
*out_version = server_hello.legacy_version;
return true;
}
if (!CBS_get_u16(&supported_versions.data, out_version) ||
CBS_len(&supported_versions.data) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return false;
}
return true;
}
// should_offer_early_data returns |ssl_early_data_accepted| if |hs| should
// offer early data, and some other reason code otherwise.
static ssl_early_data_reason_t should_offer_early_data(
const SSL_HANDSHAKE *hs) {
const SSL *const ssl = hs->ssl;
assert(!ssl->server);
if (!ssl->enable_early_data) {
return ssl_early_data_disabled;
}
if (hs->max_version < TLS1_3_VERSION) {
// We discard inapplicable sessions, so this is redundant with the session
// checks below, but reporting that TLS 1.3 was disabled is more useful.
return ssl_early_data_protocol_version;
}
if (ssl->session == nullptr) {
return ssl_early_data_no_session_offered;
}
if (ssl_session_protocol_version(ssl->session.get()) < TLS1_3_VERSION ||
ssl->session->ticket_max_early_data == 0) {
return ssl_early_data_unsupported_for_session;
}
if (!ssl->session->early_alpn.empty()) {
if (!ssl_is_alpn_protocol_allowed(hs, ssl->session->early_alpn)) {
// Avoid reporting a confusing value in |SSL_get0_alpn_selected|.
return ssl_early_data_alpn_mismatch;
}
// If the previous connection negotiated ALPS, only offer 0-RTT when the
// local are settings are consistent with what we'd offer for this
// connection.
if (ssl->session->has_application_settings) {
Span<const uint8_t> settings;
if (!ssl_get_local_application_settings(hs, &settings,
ssl->session->early_alpn) ||
settings != ssl->session->local_application_settings) {
return ssl_early_data_alps_mismatch;
}
}
}
// Early data has not yet been accepted, but we use it as a success code.
return ssl_early_data_accepted;
}
void ssl_done_writing_client_hello(SSL_HANDSHAKE *hs) {
hs->ech_client_outer.Reset();
hs->cookie.Reset();
hs->key_share_bytes.Reset();
}
static enum ssl_hs_wait_t do_start_connect(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_START, 1);
ssl_update_counter(ssl->session_ctx.get(),
ssl->session_ctx->stats.sess_connect, true);
// |session_reused| must be reset in case this is a renegotiation.
ssl->s3->session_reused = false;
// Freeze the version range.
if (!ssl_get_version_range(hs, &hs->min_version, &hs->max_version)) {
return ssl_hs_error;
}
uint8_t ech_enc[EVP_HPKE_MAX_ENC_LENGTH];
size_t ech_enc_len;
if (!ssl_select_ech_config(hs, ech_enc, &ech_enc_len)) {
return ssl_hs_error;
}
// Always advertise the ClientHello version from the original maximum version,
// even on renegotiation. The static RSA key exchange uses this field, and
// some servers fail when it changes across handshakes.
if (SSL_is_dtls(hs->ssl)) {
hs->client_version =
hs->max_version >= TLS1_2_VERSION ? DTLS1_2_VERSION : DTLS1_VERSION;
} else {
hs->client_version =
hs->max_version >= TLS1_2_VERSION ? TLS1_2_VERSION : hs->max_version;
}
// If the configured session has expired or is not usable, drop it. We also do
// not offer sessions on renegotiation.
if (ssl->session != nullptr) {
if (ssl->session->is_server ||
!ssl_supports_version(hs, ssl->session->ssl_version) ||
// Do not offer TLS 1.2 sessions with ECH. ClientHelloInner does not
// offer TLS 1.2, and the cleartext session ID may leak the server
// identity.
(hs->selected_ech_config &&
ssl_session_protocol_version(ssl->session.get()) < TLS1_3_VERSION) ||
!SSL_SESSION_is_resumable(ssl->session.get()) ||
!ssl_session_is_time_valid(ssl, ssl->session.get()) ||
(ssl->quic_method != nullptr) != ssl->session->is_quic ||
ssl->s3->initial_handshake_complete) {
ssl_set_session(ssl, nullptr);
}
}
if (!RAND_bytes(ssl->s3->client_random, sizeof(ssl->s3->client_random))) {
return ssl_hs_error;
}
if (hs->selected_ech_config &&
!RAND_bytes(hs->inner_client_random, sizeof(hs->inner_client_random))) {
return ssl_hs_error;
}
// Never send a session ID in QUIC. QUIC uses TLS 1.3 at a minimum and
// disables TLS 1.3 middlebox compatibility mode.
if (ssl->quic_method == nullptr) {
const bool has_id_session = ssl->session != nullptr &&
ssl->session->session_id_length > 0 &&
ssl->session->ticket.empty();
const bool has_ticket_session =
ssl->session != nullptr && !ssl->session->ticket.empty();
if (has_id_session) {
hs->session_id_len = ssl->session->session_id_length;
OPENSSL_memcpy(hs->session_id, ssl->session->session_id,
hs->session_id_len);
} else if (has_ticket_session || hs->max_version >= TLS1_3_VERSION) {
// Send a random session ID. TLS 1.3 always sends one, and TLS 1.2 session
// tickets require a placeholder value to signal resumption.
hs->session_id_len = sizeof(hs->session_id);
if (!RAND_bytes(hs->session_id, hs->session_id_len)) {
return ssl_hs_error;
}
}
}
ssl_early_data_reason_t reason = should_offer_early_data(hs);
if (reason != ssl_early_data_accepted) {
ssl->s3->early_data_reason = reason;
} else {
hs->early_data_offered = true;
}
if (!ssl_setup_key_shares(hs, /*override_group_id=*/0) ||
!ssl_setup_extension_permutation(hs) ||
!ssl_encrypt_client_hello(hs, MakeConstSpan(ech_enc, ech_enc_len)) ||
!ssl_add_client_hello(hs)) {
return ssl_hs_error;
}
hs->state = state_enter_early_data;
return ssl_hs_flush;
}
static enum ssl_hs_wait_t do_enter_early_data(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (SSL_is_dtls(ssl)) {
hs->state = state_read_hello_verify_request;
return ssl_hs_ok;
}
if (!hs->early_data_offered) {
hs->state = state_read_server_hello;
return ssl_hs_ok;
}
ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->session->ssl_version);
if (!ssl->method->add_change_cipher_spec(ssl)) {
return ssl_hs_error;
}
if (!tls13_init_early_key_schedule(hs, ssl->session.get()) ||
!tls13_derive_early_secret(hs)) {
return ssl_hs_error;
}
// Stash the early data session, so connection properties may be queried out
// of it.
hs->early_session = UpRef(ssl->session);
hs->state = state_early_reverify_server_certificate;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_early_reverify_server_certificate(SSL_HANDSHAKE *hs) {
if (hs->ssl->ctx->reverify_on_resume) {
// Don't send an alert on error. The alert be in early data, which the
// server may not accept anyway. It would also be a mismatch between QUIC
// and TCP because the QUIC early keys are deferred below.
//
// TODO(davidben): The client behavior should be to verify the certificate
// before deciding whether to offer the session and, if invalid, decline to
// send the session.
switch (ssl_reverify_peer_cert(hs, /*send_alert=*/false)) {
case ssl_verify_ok:
break;
case ssl_verify_invalid:
return ssl_hs_error;
case ssl_verify_retry:
hs->state = state_early_reverify_server_certificate;
return ssl_hs_certificate_verify;
}
}
// Defer releasing the 0-RTT key to after certificate reverification, so the
// QUIC implementation does not accidentally write data too early.
if (!tls13_set_traffic_key(hs->ssl, ssl_encryption_early_data, evp_aead_seal,
hs->early_session.get(),
hs->early_traffic_secret())) {
return ssl_hs_error;
}
hs->in_early_data = true;
hs->can_early_write = true;
hs->state = state_read_server_hello;
return ssl_hs_early_return;
}
static enum ssl_hs_wait_t do_read_hello_verify_request(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
assert(SSL_is_dtls(ssl));
// When implementing DTLS 1.3, we need to handle the interactions between
// HelloVerifyRequest, DTLS 1.3's HelloVerifyRequest removal, and ECH.
assert(hs->max_version < TLS1_3_VERSION);
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (msg.type != DTLS1_MT_HELLO_VERIFY_REQUEST) {
hs->state = state_read_server_hello;
return ssl_hs_ok;
}
CBS hello_verify_request = msg.body, cookie;
uint16_t server_version;
if (!CBS_get_u16(&hello_verify_request, &server_version) ||
!CBS_get_u8_length_prefixed(&hello_verify_request, &cookie) ||
CBS_len(&hello_verify_request) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
if (!hs->dtls_cookie.CopyFrom(cookie)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
ssl->method->next_message(ssl);
// DTLS resets the handshake buffer after HelloVerifyRequest.
if (!hs->transcript.Init()) {
return ssl_hs_error;
}
if (!ssl_add_client_hello(hs)) {
return ssl_hs_error;
}
hs->state = state_read_server_hello;
return ssl_hs_flush;
}
bool ssl_parse_server_hello(ParsedServerHello *out, uint8_t *out_alert,
const SSLMessage &msg) {
if (msg.type != SSL3_MT_SERVER_HELLO) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
*out_alert = SSL_AD_UNEXPECTED_MESSAGE;
return false;
}
out->raw = msg.raw;
CBS body = msg.body;
if (!CBS_get_u16(&body, &out->legacy_version) ||
!CBS_get_bytes(&body, &out->random, SSL3_RANDOM_SIZE) ||
!CBS_get_u8_length_prefixed(&body, &out->session_id) ||
CBS_len(&out->session_id) > SSL3_SESSION_ID_SIZE ||
!CBS_get_u16(&body, &out->cipher_suite) ||
!CBS_get_u8(&body, &out->compression_method)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
*out_alert = SSL_AD_DECODE_ERROR;
return false;
}
// In TLS 1.2 and below, empty extensions blocks may be omitted. In TLS 1.3,
// ServerHellos always have extensions, so this can be applied generically.
CBS_init(&out->extensions, nullptr, 0);
if ((CBS_len(&body) != 0 &&
!CBS_get_u16_length_prefixed(&body, &out->extensions)) ||
CBS_len(&body) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
*out_alert = SSL_AD_DECODE_ERROR;
return false;
}
return true;
}
static enum ssl_hs_wait_t do_read_server_hello(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_server_hello;
}
ParsedServerHello server_hello;
uint16_t server_version;
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ssl_parse_server_hello(&server_hello, &alert, msg) ||
!parse_server_version(hs, &server_version, &alert, server_hello)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
if (!ssl_supports_version(hs, server_version)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
return ssl_hs_error;
}
assert(ssl->s3->have_version == ssl->s3->initial_handshake_complete);
if (!ssl->s3->have_version) {
ssl->version = server_version;
// At this point, the connection's version is known and ssl->version is
// fixed. Begin enforcing the record-layer version.
ssl->s3->have_version = true;
ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version);
} else if (server_version != ssl->version) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SSL_VERSION);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
return ssl_hs_error;
}
if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
hs->state = state_tls13;
return ssl_hs_ok;
}
// Clear some TLS 1.3 state that no longer needs to be retained.
hs->key_shares[0].reset();
hs->key_shares[1].reset();
ssl_done_writing_client_hello(hs);
// A TLS 1.2 server would not know to skip the early data we offered. Report
// an error code sooner. The caller may use this error code to implement the
// fallback described in RFC 8446 appendix D.3.
if (hs->early_data_offered) {
// Disconnect early writes. This ensures subsequent |SSL_write| calls query
// the handshake which, in turn, will replay the error code rather than fail
// at the |write_shutdown| check. See https://crbug.com/1078515.
// TODO(davidben): Should all handshake errors do this? What about record
// decryption failures?
hs->can_early_write = false;
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_ON_EARLY_DATA);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
return ssl_hs_error;
}
// TLS 1.2 handshakes cannot accept ECH.
if (hs->selected_ech_config) {
ssl->s3->ech_status = ssl_ech_rejected;
}
// Copy over the server random.
OPENSSL_memcpy(ssl->s3->server_random, CBS_data(&server_hello.random),
SSL3_RANDOM_SIZE);
// Enforce the TLS 1.3 anti-downgrade feature.
if (!ssl->s3->initial_handshake_complete &&
ssl_supports_version(hs, TLS1_3_VERSION)) {
static_assert(
sizeof(kTLS12DowngradeRandom) == sizeof(kTLS13DowngradeRandom),
"downgrade signals have different size");
static_assert(
sizeof(kJDK11DowngradeRandom) == sizeof(kTLS13DowngradeRandom),
"downgrade signals have different size");
auto suffix =
MakeConstSpan(ssl->s3->server_random, sizeof(ssl->s3->server_random))
.subspan(SSL3_RANDOM_SIZE - sizeof(kTLS13DowngradeRandom));
if (suffix == kTLS12DowngradeRandom || suffix == kTLS13DowngradeRandom ||
suffix == kJDK11DowngradeRandom) {
OPENSSL_PUT_ERROR(SSL, SSL_R_TLS13_DOWNGRADE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
}
// The cipher must be allowed in the selected version and enabled.
const SSL_CIPHER *cipher = SSL_get_cipher_by_value(server_hello.cipher_suite);
uint32_t mask_a, mask_k;
ssl_get_client_disabled(hs, &mask_a, &mask_k);
if (cipher == nullptr ||
(cipher->algorithm_mkey & mask_k) ||
(cipher->algorithm_auth & mask_a) ||
SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) ||
SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl) ||
!sk_SSL_CIPHER_find_awslc(SSL_get_ciphers(ssl), nullptr, cipher)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
hs->new_cipher = cipher;
if (hs->session_id_len != 0 &&
CBS_mem_equal(&server_hello.session_id, hs->session_id,
hs->session_id_len)) {
// Echoing the ClientHello session ID in TLS 1.2, whether from the session
// or a synthetic one, indicates resumption. If there was no session (or if
// the session was only offered in ECH ClientHelloInner), this was the
// TLS 1.3 compatibility mode session ID. As we know this is not a session
// the server knows about, any server resuming it is in error. Reject the
// first connection deterministicly, rather than installing an invalid
// session into the session cache. https://crbug.com/796910
if (ssl->session == nullptr || ssl->s3->ech_status == ssl_ech_rejected) {
OPENSSL_PUT_ERROR(SSL, SSL_R_SERVER_ECHOED_INVALID_SESSION_ID);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
if (ssl->session->ssl_version != ssl->version) {
OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_VERSION_NOT_RETURNED);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
if (ssl->session->cipher != hs->new_cipher) {
OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
if (!ssl_session_is_context_valid(hs, ssl->session.get())) {
// This is actually a client application bug.
OPENSSL_PUT_ERROR(SSL,
SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
// We never offer sessions on renegotiation.
assert(!ssl->s3->initial_handshake_complete);
ssl->s3->session_reused = true;
} else {
// The session wasn't resumed. Create a fresh SSL_SESSION to fill out.
ssl_set_session(ssl, NULL);
if (!ssl_get_new_session(hs)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
// Save the session ID from the server. This may be empty if the session
// isn't resumable, or if we'll receive a session ticket later.
assert(CBS_len(&server_hello.session_id) <= SSL3_SESSION_ID_SIZE);
static_assert(SSL3_SESSION_ID_SIZE <= UINT8_MAX,
"max session ID is too large");
hs->new_session->session_id_length =
static_cast<uint8_t>(CBS_len(&server_hello.session_id));
OPENSSL_memcpy(hs->new_session->session_id,
CBS_data(&server_hello.session_id),
CBS_len(&server_hello.session_id));
hs->new_session->cipher = hs->new_cipher;
}
// Now that the cipher is known, initialize the handshake hash and hash the
// ServerHello.
if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) ||
!ssl_hash_message(hs, msg)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
// If doing a full handshake, the server may request a client certificate
// which requires hashing the handshake transcript. Otherwise, the handshake
// buffer may be released.
if (ssl->session != NULL ||
!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->transcript.FreeBuffer();
}
// Only the NULL compression algorithm is supported.
if (server_hello.compression_method != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
if (!ssl_parse_serverhello_tlsext(hs, &server_hello.extensions)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
return ssl_hs_error;
}
if (ssl->session != NULL &&
hs->extended_master_secret != ssl->session->extended_master_secret) {
if (ssl->session->extended_master_secret) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION);
} else {
OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_NON_EMS_SESSION_WITH_EMS_EXTENSION);
}
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
ssl->method->next_message(ssl);
if (ssl->session != NULL) {
if (ssl->ctx->reverify_on_resume &&
ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->state = state_reverify_server_certificate;
} else {
hs->state = state_read_session_ticket;
}
return ssl_hs_ok;
}
hs->state = state_read_server_certificate;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) {
enum ssl_hs_wait_t wait = tls13_client_handshake(hs);
if (wait == ssl_hs_ok) {
hs->state = state_finish_client_handshake;
return ssl_hs_ok;
}
return wait;
}
static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->state = state_read_certificate_status;
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_CERTIFICATE) ||
!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
CBS body = msg.body;
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ssl_parse_cert_chain(&alert, &hs->new_session->certs, &hs->peer_pubkey,
NULL, &body, ssl->ctx->pool)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
if (sk_CRYPTO_BUFFER_num(hs->new_session->certs.get()) == 0 ||
CBS_len(&body) != 0 ||
!ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
if (!ssl_check_leaf_certificate(
hs, hs->peer_pubkey.get(),
sk_CRYPTO_BUFFER_value(hs->new_session->certs.get(), 0))) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
ssl->method->next_message(ssl);
hs->state = state_read_certificate_status;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_certificate_status(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!hs->certificate_status_expected) {
hs->state = state_verify_server_certificate;
return ssl_hs_ok;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (msg.type != SSL3_MT_CERTIFICATE_STATUS) {
// A server may send status_request in ServerHello and then change its mind
// about sending CertificateStatus.
hs->state = state_verify_server_certificate;
return ssl_hs_ok;
}
if (!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
CBS certificate_status = msg.body, ocsp_response;
uint8_t status_type;
if (!CBS_get_u8(&certificate_status, &status_type) ||
status_type != TLSEXT_STATUSTYPE_ocsp ||
!CBS_get_u24_length_prefixed(&certificate_status, &ocsp_response) ||
CBS_len(&ocsp_response) == 0 ||
CBS_len(&certificate_status) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
hs->new_session->ocsp_response.reset(
CRYPTO_BUFFER_new_from_CBS(&ocsp_response, ssl->ctx->pool));
if (hs->new_session->ocsp_response == nullptr) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
ssl->method->next_message(ssl);
hs->state = state_verify_server_certificate;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_verify_server_certificate(SSL_HANDSHAKE *hs) {
if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->state = state_read_server_key_exchange;
return ssl_hs_ok;
}
switch (ssl_verify_peer_cert(hs)) {
case ssl_verify_ok:
break;
case ssl_verify_invalid:
return ssl_hs_error;
case ssl_verify_retry:
hs->state = state_verify_server_certificate;
return ssl_hs_certificate_verify;
}
hs->state = state_read_server_key_exchange;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_reverify_server_certificate(SSL_HANDSHAKE *hs) {
assert(hs->ssl->ctx->reverify_on_resume);
switch (ssl_reverify_peer_cert(hs, /*send_alert=*/true)) {
case ssl_verify_ok:
break;
case ssl_verify_invalid:
return ssl_hs_error;
case ssl_verify_retry:
hs->state = state_reverify_server_certificate;
return ssl_hs_certificate_verify;
}
hs->state = state_read_session_ticket;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_server_key_exchange(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (msg.type != SSL3_MT_SERVER_KEY_EXCHANGE) {
// Some ciphers (pure PSK) have an optional ServerKeyExchange message.
if (ssl_cipher_requires_server_key_exchange(hs->new_cipher)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return ssl_hs_error;
}
hs->state = state_read_certificate_request;
return ssl_hs_ok;
}
if (!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
uint32_t alg_k = hs->new_cipher->algorithm_mkey;
uint32_t alg_a = hs->new_cipher->algorithm_auth;
CBS server_key_exchange = msg.body;
if (alg_a & SSL_aPSK) {
CBS psk_identity_hint;
// Each of the PSK key exchanges begins with a psk_identity_hint.
if (!CBS_get_u16_length_prefixed(&server_key_exchange,
&psk_identity_hint)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
// Store the PSK identity hint for the ClientKeyExchange. Assume that the
// maximum length of a PSK identity hint can be as long as the maximum
// length of a PSK identity. Also do not allow NULL characters; identities
// are saved as C strings.
//
// TODO(davidben): Should invalid hints be ignored? It's a hint rather than
// a specific identity.
if (CBS_len(&psk_identity_hint) > PSK_MAX_IDENTITY_LEN ||
CBS_contains_zero_byte(&psk_identity_hint)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
// Save non-empty identity hints as a C string. Empty identity hints we
// treat as missing. Plain PSK makes it possible to send either no hint
// (omit ServerKeyExchange) or an empty hint, while ECDHE_PSK can only spell
// empty hint. Having different capabilities is odd, so we interpret empty
// and missing as identical.
char *raw = nullptr;
if (CBS_len(&psk_identity_hint) != 0 &&
!CBS_strdup(&psk_identity_hint, &raw)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
hs->peer_psk_identity_hint.reset(raw);
}
if (alg_k & SSL_kECDHE) {
// Parse the server parameters.
uint8_t group_type;
uint16_t group_id;
CBS point;
if (!CBS_get_u8(&server_key_exchange, &group_type) ||
group_type != NAMED_CURVE_TYPE ||
!CBS_get_u16(&server_key_exchange, &group_id) ||
!CBS_get_u8_length_prefixed(&server_key_exchange, &point)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
// Ensure the group is consistent with preferences.
if (!tls1_check_group_id(hs, group_id)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
// Save the group and peer public key for later.
hs->new_session->group_id = group_id;
if (!ssl->s3->peer_key.CopyFrom(point)) {
return ssl_hs_error;
}
} else if (!(alg_k & SSL_kPSK)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return ssl_hs_error;
}
// At this point, |server_key_exchange| contains the signature, if any, while
// |msg.body| contains the entire message. From that, derive a CBS containing
// just the parameter.
CBS parameter;
CBS_init(&parameter, CBS_data(&msg.body),
CBS_len(&msg.body) - CBS_len(&server_key_exchange));
// ServerKeyExchange should be signed by the server's public key.
if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
uint16_t signature_algorithm = 0;
if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
if (!CBS_get_u16(&server_key_exchange, &signature_algorithm)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!tls12_check_peer_sigalg(hs, &alert, signature_algorithm)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
hs->new_session->peer_signature_algorithm = signature_algorithm;
} else if (!tls1_get_legacy_signature_algorithm(&signature_algorithm,
hs->peer_pubkey.get())) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE);
return ssl_hs_error;
}
// The last field in |server_key_exchange| is the signature.
CBS signature;
if (!CBS_get_u16_length_prefixed(&server_key_exchange, &signature) ||
CBS_len(&server_key_exchange) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
ScopedCBB transcript;
Array<uint8_t> transcript_data;
if (!CBB_init(transcript.get(),
2 * SSL3_RANDOM_SIZE + CBS_len(&parameter)) ||
!CBB_add_bytes(transcript.get(), ssl->s3->client_random,
SSL3_RANDOM_SIZE) ||
!CBB_add_bytes(transcript.get(), ssl->s3->server_random,
SSL3_RANDOM_SIZE) ||
!CBB_add_bytes(transcript.get(), CBS_data(&parameter),
CBS_len(&parameter)) ||
!CBBFinishArray(transcript.get(), &transcript_data)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
if (!ssl_public_key_verify(ssl, signature, signature_algorithm,
hs->peer_pubkey.get(), transcript_data)) {
// bad signature
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
return ssl_hs_error;
}
} else {
// PSK ciphers are the only supported certificate-less ciphers.
assert(alg_a == SSL_aPSK);
if (CBS_len(&server_key_exchange) > 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_EXTRA_DATA_IN_MESSAGE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
}
ssl->method->next_message(ssl);
hs->state = state_read_certificate_request;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->state = state_read_server_hello_done;
return ssl_hs_ok;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (msg.type == SSL3_MT_SERVER_HELLO_DONE) {
// If we get here we don't need the handshake buffer as we won't be doing
// client auth.
hs->transcript.FreeBuffer();
hs->state = state_read_server_hello_done;
return ssl_hs_ok;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_REQUEST) ||
!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
// Get the certificate types.
CBS body = msg.body, certificate_types;
if (!CBS_get_u8_length_prefixed(&body, &certificate_types)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
return ssl_hs_error;
}
if (!hs->certificate_types.CopyFrom(certificate_types)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
CBS supported_signature_algorithms;
if (!CBS_get_u16_length_prefixed(&body, &supported_signature_algorithms) ||
!tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
return ssl_hs_error;
}
}
uint8_t alert = SSL_AD_DECODE_ERROR;
UniquePtr<STACK_OF(CRYPTO_BUFFER)> ca_names =
ssl_parse_client_CA_list(ssl, &alert, &body);
if (!ca_names) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
if (CBS_len(&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;
}
hs->cert_request = true;
hs->ca_names = std::move(ca_names);
ssl->ctx->x509_method->hs_flush_cached_ca_names(hs);
ssl->method->next_message(ssl);
hs->state = state_read_server_hello_done;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_server_hello_done(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_SERVER_HELLO_DONE) ||
!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
// ServerHelloDone is empty.
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;
}
// ServerHelloDone 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->state = state_send_client_certificate;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_send_client_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
// The peer didn't request a certificate.
if (!hs->cert_request) {
hs->state = state_send_client_key_exchange;
return ssl_hs_ok;
}
if (ssl->s3->ech_status == ssl_ech_rejected) {
// Do not send client certificates on ECH reject. We have not authenticated
// the server for the name that can learn the certificate.
SSL_certs_clear(ssl);
} else if (hs->config->cert->cert_cb != nullptr) {
// Call cert_cb to update the certificate.
int rv = hs->config->cert->cert_cb(ssl, hs->config->cert->cert_cb_arg);
if (rv == 0) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
return ssl_hs_error;
}
if (rv < 0) {
hs->state = state_send_client_certificate;
return ssl_hs_x509_lookup;
}
}
if (!ssl_on_certificate_selected(hs)) {
return ssl_hs_error;
}
if (ssl_has_certificate(hs)) {
if (hs->config->check_client_certificate_type) {
// Check the certificate types advertised by the peer.
uint8_t cert_type;
switch (EVP_PKEY_id(hs->local_pubkey.get())) {
case EVP_PKEY_RSA:
cert_type = SSL3_CT_RSA_SIGN;
break;
case EVP_PKEY_EC:
case EVP_PKEY_ED25519:
cert_type = TLS_CT_ECDSA_SIGN;
break;
default:
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CERTIFICATE_TYPE);
return ssl_hs_error;
}
if (std::find(hs->certificate_types.begin(), hs->certificate_types.end(),
cert_type) == hs->certificate_types.end()) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CERTIFICATE_TYPE);
return ssl_hs_error;
}
}
} else {
// Without a client certificate, the handshake buffer may be released.
hs->transcript.FreeBuffer();
}
if (!ssl_output_cert_chain(hs)) {
return ssl_hs_error;
}
hs->state = state_send_client_key_exchange;
return ssl_hs_ok;
}
static_assert(sizeof(size_t) >= sizeof(unsigned),
"size_t is smaller than unsigned");
static enum ssl_hs_wait_t do_send_client_key_exchange(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ScopedCBB cbb;
CBB body;
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_CLIENT_KEY_EXCHANGE)) {
return ssl_hs_error;
}
Array<uint8_t> pms;
uint32_t alg_k = hs->new_cipher->algorithm_mkey;
uint32_t alg_a = hs->new_cipher->algorithm_auth;
if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
const CRYPTO_BUFFER *leaf =
sk_CRYPTO_BUFFER_value(hs->new_session->certs.get(), 0);
CBS leaf_cbs;
CRYPTO_BUFFER_init_CBS(leaf, &leaf_cbs);
// Check the key usage matches the cipher suite. We do this unconditionally
// for non-RSA certificates. In particular, it's needed to distinguish ECDH
// certificates, which we do not support, from ECDSA certificates.
// Historically, we have not checked RSA key usages, so it is controlled by
// a flag for now. See https://crbug.com/795089.
ssl_key_usage_t intended_use = (alg_k & SSL_kRSA)
? key_usage_encipherment
: key_usage_digital_signature;
if (!ssl_cert_check_key_usage(&leaf_cbs, intended_use)) {
if (hs->config->enforce_rsa_key_usage ||
EVP_PKEY_id(hs->peer_pubkey.get()) != EVP_PKEY_RSA) {
return ssl_hs_error;
}
ERR_clear_error();
ssl->s3->was_key_usage_invalid = true;
}
}
// If using a PSK key exchange, prepare the pre-shared key.
unsigned psk_len = 0;
uint8_t psk[PSK_MAX_PSK_LEN];
if (alg_a & SSL_aPSK) {
if (hs->config->psk_client_callback == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_NO_CLIENT_CB);
return ssl_hs_error;
}
char identity[PSK_MAX_IDENTITY_LEN + 1];
OPENSSL_memset(identity, 0, sizeof(identity));
psk_len = hs->config->psk_client_callback(
ssl, hs->peer_psk_identity_hint.get(), identity, sizeof(identity), psk,
sizeof(psk));
if (psk_len == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
assert(psk_len <= PSK_MAX_PSK_LEN);
hs->new_session->psk_identity.reset(OPENSSL_strdup(identity));
if (hs->new_session->psk_identity == nullptr) {
return ssl_hs_error;
}
// Write out psk_identity.
CBB child;
if (!CBB_add_u16_length_prefixed(&body, &child) ||
!CBB_add_bytes(&child, (const uint8_t *)identity,
OPENSSL_strnlen(identity, sizeof(identity))) ||
!CBB_flush(&body)) {
return ssl_hs_error;
}
}
// Depending on the key exchange method, compute |pms|.
if (alg_k & SSL_kRSA) {
if (!pms.Init(SSL_MAX_MASTER_KEY_LENGTH)) {
return ssl_hs_error;
}
RSA *rsa = EVP_PKEY_get0_RSA(hs->peer_pubkey.get());
if (rsa == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
pms[0] = hs->client_version >> 8;
pms[1] = hs->client_version & 0xff;
if (!RAND_bytes(&pms[2], SSL_MAX_MASTER_KEY_LENGTH - 2)) {
return ssl_hs_error;
}
CBB enc_pms;
uint8_t *ptr;
size_t enc_pms_len;
if (!CBB_add_u16_length_prefixed(&body, &enc_pms) ||
!CBB_reserve(&enc_pms, &ptr, RSA_size(rsa)) ||
!RSA_encrypt(rsa, &enc_pms_len, ptr, RSA_size(rsa), pms.data(),
pms.size(), RSA_PKCS1_PADDING) ||
!CBB_did_write(&enc_pms, enc_pms_len) ||
!CBB_flush(&body)) {
return ssl_hs_error;
}
} else if (alg_k & SSL_kECDHE) {
CBB child;
if (!CBB_add_u8_length_prefixed(&body, &child)) {
return ssl_hs_error;
}
// Generate the premaster secret.
bssl::UniquePtr<SSLKeyShare> key_share =
SSLKeyShare::Create(hs->new_session->group_id);
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!key_share ||
!key_share->Accept(&child, &pms, &alert, ssl->s3->peer_key)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
if (!CBB_flush(&body)) {
return ssl_hs_error;
}
// The peer key could be discarded, but we preserve it since OpenSSL
// allows the user to observe it with |SSL_get_peer_tmp_key|.
} else if (alg_k & SSL_kPSK) {
// For plain PSK, other_secret is a block of 0s with the same length as
// the pre-shared key.
if (!pms.Init(psk_len)) {
return ssl_hs_error;
}
OPENSSL_memset(pms.data(), 0, pms.size());
} else {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
// For a PSK cipher suite, other_secret is combined with the pre-shared
// key.
if (alg_a & SSL_aPSK) {
ScopedCBB pms_cbb;
CBB child;
if (!CBB_init(pms_cbb.get(), 2 + psk_len + 2 + pms.size()) ||
!CBB_add_u16_length_prefixed(pms_cbb.get(), &child) ||
!CBB_add_bytes(&child, pms.data(), pms.size()) ||
!CBB_add_u16_length_prefixed(pms_cbb.get(), &child) ||
!CBB_add_bytes(&child, psk, psk_len) ||
!CBBFinishArray(pms_cbb.get(), &pms)) {
return ssl_hs_error;
}
}
// The message must be added to the finished hash before calculating the
// master secret.
if (!ssl_add_message_cbb(ssl, cbb.get())) {
return ssl_hs_error;
}
hs->new_session->secret_length =
tls1_generate_master_secret(hs, hs->new_session->secret, pms);
if (hs->new_session->secret_length == 0) {
return ssl_hs_error;
}
hs->new_session->extended_master_secret = hs->extended_master_secret;
hs->state = state_send_client_certificate_verify;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!hs->cert_request || !ssl_has_certificate(hs)) {
hs->state = state_send_client_finished;
return ssl_hs_ok;
}
assert(ssl_has_private_key(hs));
ScopedCBB cbb;
CBB body, child;
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_CERTIFICATE_VERIFY)) {
return ssl_hs_error;
}
if (!tls1_choose_signature_algorithm(hs, &hs->signature_algorithm)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
// Write out the digest type in TLS 1.2.
if (!CBB_add_u16(&body, hs->signature_algorithm)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
}
// Set aside space for the signature.
const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get());
uint8_t *ptr;
if (!CBB_add_u16_length_prefixed(&body, &child) ||
!CBB_reserve(&child, &ptr, max_sig_len)) {
return ssl_hs_error;
}
size_t sig_len = max_sig_len;
switch (ssl_private_key_sign(hs, ptr, &sig_len, max_sig_len,
hs->signature_algorithm,
hs->transcript.buffer())) {
case ssl_private_key_success:
break;
case ssl_private_key_failure:
return ssl_hs_error;
case ssl_private_key_retry:
hs->state = state_send_client_certificate_verify;
return ssl_hs_private_key_operation;
}
if (!CBB_did_write(&child, sig_len) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
return ssl_hs_error;
}
// The handshake buffer is no longer necessary.
hs->transcript.FreeBuffer();
hs->state = state_send_client_finished;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_send_client_finished(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
hs->can_release_private_key = true;
if (!ssl->method->add_change_cipher_spec(ssl) ||
!tls1_change_cipher_state(hs, evp_aead_seal)) {
return ssl_hs_error;
}
if (hs->next_proto_neg_seen) {
static const uint8_t kZero[32] = {0};
size_t padding_len =
32 - ((ssl->s3->next_proto_negotiated.size() + 2) % 32);
ScopedCBB cbb;
CBB body, child;
if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_NEXT_PROTO) ||
!CBB_add_u8_length_prefixed(&body, &child) ||
!CBB_add_bytes(&child, ssl->s3->next_proto_negotiated.data(),
ssl->s3->next_proto_negotiated.size()) ||
!CBB_add_u8_length_prefixed(&body, &child) ||
!CBB_add_bytes(&child, kZero, padding_len) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
}
if (hs->channel_id_negotiated) {
ScopedCBB cbb;
CBB body;
if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CHANNEL_ID) ||
!tls1_write_channel_id(hs, &body) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
}
if (!ssl_send_finished(hs)) {
return ssl_hs_error;
}
hs->state = state_finish_flight;
return ssl_hs_flush;
}
static bool can_false_start(const SSL_HANDSHAKE *hs) {
const SSL *const ssl = hs->ssl;
// False Start bypasses the Finished check's downgrade protection. This can
// enable attacks where we send data under weaker settings than supported
// (e.g. the Logjam attack). Thus we require TLS 1.2 with an ECDHE+AEAD
// cipher, our strongest settings before TLS 1.3.
//
// Now that TLS 1.3 exists, we would like to avoid similar attacks between
// TLS 1.2 and TLS 1.3, but there are too many TLS 1.2 deployments to
// sacrifice False Start on them. Instead, we rely on the ServerHello.random
// downgrade signal, which we unconditionally enforce.
if (SSL_is_dtls(ssl) ||
SSL_version(ssl) != TLS1_2_VERSION ||
hs->new_cipher->algorithm_mkey != SSL_kECDHE ||
hs->new_cipher->algorithm_mac != SSL_AEAD) {
return false;
}
// If ECH was rejected, disable False Start. We run the handshake to
// completion, including the Finished downgrade check, to authenticate the
// recovery flow.
if (ssl->s3->ech_status == ssl_ech_rejected) {
return false;
}
// Additionally require ALPN or NPN by default.
//
// TODO(davidben): Can this constraint be relaxed globally now that cipher
// suite requirements have been tightened?
if (!ssl->ctx->false_start_allowed_without_alpn &&
ssl->s3->alpn_selected.empty() &&
ssl->s3->next_proto_negotiated.empty()) {
return false;
}
return true;
}
static enum ssl_hs_wait_t do_finish_flight(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (ssl->session != NULL) {
hs->state = state_finish_client_handshake;
return ssl_hs_ok;
}
// This is a full handshake. If it involves ChannelID, then record the
// handshake hashes at this point in the session so that any resumption of
// this session with ChannelID can sign those hashes.
if (!tls1_record_handshake_hashes_for_channel_id(hs)) {
return ssl_hs_error;
}
hs->state = state_read_session_ticket;
if ((SSL_get_mode(ssl) & SSL_MODE_ENABLE_FALSE_START) &&
can_false_start(hs) &&
// No False Start on renegotiation (would complicate the state machine).
!ssl->s3->initial_handshake_complete) {
hs->in_false_start = true;
hs->can_early_write = true;
return ssl_hs_early_return;
}
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_session_ticket(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!hs->ticket_expected) {
hs->state = state_process_change_cipher_spec;
return ssl_hs_read_change_cipher_spec;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEW_SESSION_TICKET) ||
!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
CBS new_session_ticket = msg.body, ticket;
uint32_t ticket_lifetime_hint;
if (!CBS_get_u32(&new_session_ticket, &ticket_lifetime_hint) ||
!CBS_get_u16_length_prefixed(&new_session_ticket, &ticket) ||
CBS_len(&new_session_ticket) != 0) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
return ssl_hs_error;
}
if (CBS_len(&ticket) == 0) {
// RFC 5077 allows a server to change its mind and send no ticket after
// negotiating the extension. The value of |ticket_expected| is checked in
// |ssl_update_cache| so is cleared here to avoid an unnecessary update.
hs->ticket_expected = false;
ssl->method->next_message(ssl);
hs->state = state_process_change_cipher_spec;
return ssl_hs_read_change_cipher_spec;
}
if (ssl->session != nullptr) {
// The server is sending a new ticket for an existing session. Sessions are
// immutable once established, so duplicate all but the ticket of the
// existing session.
assert(!hs->new_session);
hs->new_session =
SSL_SESSION_dup(ssl->session.get(), SSL_SESSION_INCLUDE_NONAUTH);
if (!hs->new_session) {
return ssl_hs_error;
}
}
ssl->verify_result = hs->new_session->verify_result;
// |ticket_lifetime_hint| is measured from when the ticket was issued.
ssl_session_rebase_time(ssl, hs->new_session.get());
if (!hs->new_session->ticket.CopyFrom(ticket)) {
return ssl_hs_error;
}
hs->new_session->ticket_lifetime_hint = ticket_lifetime_hint;
// Historically, OpenSSL filled in fake session IDs for ticket-based sessions.
// TODO(davidben): Are external callers relying on this? Try removing this.
SHA256(CBS_data(&ticket), CBS_len(&ticket), hs->new_session->session_id);
hs->new_session->session_id_length = SHA256_DIGEST_LENGTH;
ssl->method->next_message(ssl);
hs->state = state_process_change_cipher_spec;
return ssl_hs_read_change_cipher_spec;
}
static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) {
if (!tls1_change_cipher_state(hs, evp_aead_open)) {
return ssl_hs_error;
}
hs->state = state_read_server_finished;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_server_finished(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
enum ssl_hs_wait_t wait = ssl_get_finished(hs);
if (wait != ssl_hs_ok) {
return wait;
}
if (ssl->session != NULL) {
hs->state = state_send_client_finished;
return ssl_hs_ok;
}
hs->state = state_finish_client_handshake;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_finish_client_handshake(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (ssl->s3->ech_status == ssl_ech_rejected) {
// Release the retry configs.
hs->ech_authenticated_reject = true;
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ECH_REQUIRED);
OPENSSL_PUT_ERROR(SSL, SSL_R_ECH_REJECTED);
return ssl_hs_error;
}
ssl->method->on_handshake_complete(ssl);
// Note TLS 1.2 resumptions with ticket renewal have both |ssl->session| (the
// resumed session) and |hs->new_session| (the session with the new ticket).
bool has_new_session = hs->new_session != nullptr;
if (has_new_session) {
// When False Start is enabled, the handshake reports completion early. The
// caller may then have passed the (then unresuable) |hs->new_session| to
// another thread via |SSL_get0_session| for resumption. To avoid potential
// race conditions in such callers, we duplicate the session before
// clearing |not_resumable|.
ssl->s3->established_session =
SSL_SESSION_dup(hs->new_session.get(), SSL_SESSION_DUP_ALL);
if (!ssl->s3->established_session) {
return ssl_hs_error;
}
// Renegotiations do not participate in session resumption.
if (!ssl->s3->initial_handshake_complete) {
ssl->s3->established_session->not_resumable = false;
}
hs->new_session.reset();
} else {
assert(ssl->session != nullptr);
ssl->s3->established_session = UpRef(ssl->session);
}
hs->handshake_finalized = true;
ssl->s3->initial_handshake_complete = true;
if (has_new_session) {
ssl_update_cache(ssl);
}
if (ssl->s3->session_reused) {
// Update client side session hit counter on successfully reused sessions.
ssl_update_counter(ssl->session_ctx.get(), ssl->session_ctx->stats.sess_hit,
true);
}
hs->state = state_done;
return ssl_hs_ok;
}
enum ssl_hs_wait_t ssl_client_handshake(SSL_HANDSHAKE *hs) {
while (hs->state != state_done) {
enum ssl_hs_wait_t ret = ssl_hs_error;
enum ssl_client_hs_state_t state =
static_cast<enum ssl_client_hs_state_t>(hs->state);
switch (state) {
case state_start_connect:
ret = do_start_connect(hs);
break;
case state_enter_early_data:
ret = do_enter_early_data(hs);
break;
case state_early_reverify_server_certificate:
ret = do_early_reverify_server_certificate(hs);
break;
case state_read_hello_verify_request:
ret = do_read_hello_verify_request(hs);
break;
case state_read_server_hello:
ret = do_read_server_hello(hs);
break;
case state_tls13:
ret = do_tls13(hs);
break;
case state_read_server_certificate:
ret = do_read_server_certificate(hs);
break;
case state_read_certificate_status:
ret = do_read_certificate_status(hs);
break;
case state_verify_server_certificate:
ret = do_verify_server_certificate(hs);
break;
case state_reverify_server_certificate:
ret = do_reverify_server_certificate(hs);
break;
case state_read_server_key_exchange:
ret = do_read_server_key_exchange(hs);
break;
case state_read_certificate_request:
ret = do_read_certificate_request(hs);
break;
case state_read_server_hello_done:
ret = do_read_server_hello_done(hs);
break;
case state_send_client_certificate:
ret = do_send_client_certificate(hs);
break;
case state_send_client_key_exchange:
ret = do_send_client_key_exchange(hs);
break;
case state_send_client_certificate_verify:
ret = do_send_client_certificate_verify(hs);
break;
case state_send_client_finished:
ret = do_send_client_finished(hs);
break;
case state_finish_flight:
ret = do_finish_flight(hs);
break;
case state_read_session_ticket:
ret = do_read_session_ticket(hs);
break;
case state_process_change_cipher_spec:
ret = do_process_change_cipher_spec(hs);
break;
case state_read_server_finished:
ret = do_read_server_finished(hs);
break;
case state_finish_client_handshake:
ret = do_finish_client_handshake(hs);
break;
case state_done:
ret = ssl_hs_ok;
break;
}
if (hs->state != state) {
ssl_do_info_callback(hs->ssl, SSL_CB_CONNECT_LOOP, 1);
}
if (ret != ssl_hs_ok) {
return ret;
}
}
ssl_update_counter(hs->ssl->session_ctx.get(),
hs->ssl->session_ctx->stats.sess_connect_good, true);
ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_DONE, 1);
return ssl_hs_ok;
}
const char *ssl_client_handshake_state(SSL_HANDSHAKE *hs) {
enum ssl_client_hs_state_t state =
static_cast<enum ssl_client_hs_state_t>(hs->state);
switch (state) {
case state_start_connect:
return "TLS client start_connect";
case state_enter_early_data:
return "TLS client enter_early_data";
case state_early_reverify_server_certificate:
return "TLS client early_reverify_server_certificate";
case state_read_hello_verify_request:
return "TLS client read_hello_verify_request";
case state_read_server_hello:
return "TLS client read_server_hello";
case state_tls13:
return tls13_client_handshake_state(hs);
case state_read_server_certificate:
return "TLS client read_server_certificate";
case state_read_certificate_status:
return "TLS client read_certificate_status";
case state_verify_server_certificate:
return "TLS client verify_server_certificate";
case state_reverify_server_certificate:
return "TLS client reverify_server_certificate";
case state_read_server_key_exchange:
return "TLS client read_server_key_exchange";
case state_read_certificate_request:
return "TLS client read_certificate_request";
case state_read_server_hello_done:
return "TLS client read_server_hello_done";
case state_send_client_certificate:
return "TLS client send_client_certificate";
case state_send_client_key_exchange:
return "TLS client send_client_key_exchange";
case state_send_client_certificate_verify:
return "TLS client send_client_certificate_verify";
case state_send_client_finished:
return "TLS client send_client_finished";
case state_finish_flight:
return "TLS client finish_flight";
case state_read_session_ticket:
return "TLS client read_session_ticket";
case state_process_change_cipher_spec:
return "TLS client process_change_cipher_spec";
case state_read_server_finished:
return "TLS client read_server_finished";
case state_finish_client_handshake:
return "TLS client finish_client_handshake";
case state_done:
return "TLS client done";
}
return "TLS client unknown";
}
BSSL_NAMESPACE_END
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