MONO_API int
mono_btls_ssl_ctx_is_cipher_supported (MonoBtlsSslCtx *ctx, uint16_t value)
{
const SSL_CIPHER *cipher;
cipher = SSL_get_cipher_by_value (value);
return cipher != NULL;
}
static const SSL_CIPHER *choose_tls13_cipher(
const SSL *ssl, const SSL_CLIENT_HELLO *client_hello) {
if (client_hello->cipher_suites_len % 2 != 0) {
return NULL;
}
CBS cipher_suites;
CBS_init(&cipher_suites, client_hello->cipher_suites,
client_hello->cipher_suites_len);
const int aes_is_fine = EVP_has_aes_hardware();
const uint16_t version = ssl3_protocol_version(ssl);
const SSL_CIPHER *best = NULL;
while (CBS_len(&cipher_suites) > 0) {
uint16_t cipher_suite;
if (!CBS_get_u16(&cipher_suites, &cipher_suite)) {
return NULL;
}
/* Limit to TLS 1.3 ciphers we know about. */
const SSL_CIPHER *candidate = SSL_get_cipher_by_value(cipher_suite);
if (candidate == NULL ||
SSL_CIPHER_get_min_version(candidate) > version ||
SSL_CIPHER_get_max_version(candidate) < version) {
continue;
}
/* TLS 1.3 removes legacy ciphers, so honor the client order, but prefer
* ChaCha20 if we do not have AES hardware. */
if (aes_is_fine) {
return candidate;
}
if (candidate->algorithm_enc == SSL_CHACHA20POLY1305) {
return candidate;
}
if (best == NULL) {
best = candidate;
}
}
return best;
}
int
mono_btls_ssl_ctx_set_ciphers (MonoBtlsSslCtx *ctx, int count, const uint16_t *data,
int allow_unsupported)
{
CBB cbb;
int i, ret = 0;
if (!CBB_init (&cbb, 64))
goto err;
/* Assemble a cipher string with the specified ciphers' names. */
for (i = 0; i < count; i++) {
const char *name;
const SSL_CIPHER *cipher = SSL_get_cipher_by_value (data [i]);
if (!cipher) {
debug_printf (ctx, "mono_btls_ssl_ctx_set_ciphers(): unknown cipher %02x", data [i]);
if (!allow_unsupported)
goto err;
continue;
}
name = SSL_CIPHER_get_name (cipher);
if (i > 0 && !CBB_add_u8 (&cbb, ':'))
goto err;
if (!CBB_add_bytes (&cbb, (const uint8_t *)name, strlen(name)))
goto err;
}
/* NUL-terminate the string. */
if (!CBB_add_u8 (&cbb, 0))
goto err;
ret = SSL_CTX_set_cipher_list (ctx->ctx, (const char *)CBB_data (&cbb));
err:
CBB_cleanup (&cbb);
return ret;
}
static enum ssl_hs_wait_t do_process_server_hello(SSL *ssl, SSL_HANDSHAKE *hs) {
if (!tls13_check_message_type(ssl, SSL3_MT_SERVER_HELLO)) {
return ssl_hs_error;
}
CBS cbs, server_random, extensions;
uint16_t server_wire_version;
uint16_t cipher_suite;
CBS_init(&cbs, ssl->init_msg, ssl->init_num);
if (!CBS_get_u16(&cbs, &server_wire_version) ||
!CBS_get_bytes(&cbs, &server_random, SSL3_RANDOM_SIZE) ||
!CBS_get_u16(&cbs, &cipher_suite) ||
!CBS_get_u16_length_prefixed(&cbs, &extensions) ||
CBS_len(&cbs) != 0) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
return ssl_hs_error;
}
if (server_wire_version != ssl->version) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_NUMBER);
return ssl_hs_error;
}
/* Parse out the extensions. */
int have_key_share = 0;
CBS key_share;
while (CBS_len(&extensions) != 0) {
uint16_t type;
CBS extension;
if (!CBS_get_u16(&extensions, &type) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
switch (type) {
case TLSEXT_TYPE_key_share:
if (have_key_share) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_EXTENSION);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
key_share = extension;
have_key_share = 1;
break;
default:
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
return ssl_hs_error;
}
}
assert(ssl->s3->have_version);
memcpy(ssl->s3->server_random, CBS_data(&server_random), SSL3_RANDOM_SIZE);
ssl->hit = 0;
if (!ssl_get_new_session(ssl, 0)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
const SSL_CIPHER *cipher = SSL_get_cipher_by_value(cipher_suite);
if (cipher == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CIPHER_RETURNED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
/* Check if the cipher is disabled. */
if ((cipher->algorithm_mkey & ssl->cert->mask_k) ||
(cipher->algorithm_auth & ssl->cert->mask_a) ||
SSL_CIPHER_get_min_version(cipher) > ssl3_protocol_version(ssl) ||
SSL_CIPHER_get_max_version(cipher) < ssl3_protocol_version(ssl) ||
!sk_SSL_CIPHER_find(ssl_get_ciphers_by_id(ssl), NULL, cipher)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
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. */
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) {
if (!have_key_share) {
OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
return ssl_hs_error;
}
uint8_t *dhe_secret;
size_t dhe_secret_len;
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ext_key_share_parse_serverhello(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 (have_key_share) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
return ssl_hs_error;
}
if (!tls13_advance_key_schedule(ssl, kZeroes, hash_len)) {
return ssl_hs_error;
}
}
/* If there was no HelloRetryRequest, the version negotiation logic has
* already hashed the message. */
if (ssl->s3->hs->retry_group != 0 &&
!ssl->method->hash_current_message(ssl)) {
return ssl_hs_error;
}
if (!tls13_set_handshake_traffic(ssl)) {
return ssl_hs_error;
}
hs->state = state_process_encrypted_extensions;
return ssl_hs_read_message;
}
SSL_SESSION *SSL_SESSION_parse(CBS *cbs, const SSL_X509_METHOD *x509_method,
CRYPTO_BUFFER_POOL *pool) {
SSL_SESSION *ret = ssl_session_new(x509_method);
if (ret == NULL) {
goto err;
}
CBS session;
uint64_t version, ssl_version;
if (!CBS_get_asn1(cbs, &session, CBS_ASN1_SEQUENCE) ||
!CBS_get_asn1_uint64(&session, &version) ||
version != kVersion ||
!CBS_get_asn1_uint64(&session, &ssl_version)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
ret->ssl_version = ssl_version;
CBS cipher;
uint16_t cipher_value;
if (!CBS_get_asn1(&session, &cipher, CBS_ASN1_OCTETSTRING) ||
!CBS_get_u16(&cipher, &cipher_value) ||
CBS_len(&cipher) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
ret->cipher = SSL_get_cipher_by_value(cipher_value);
if (ret->cipher == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_CIPHER);
goto err;
}
CBS session_id, master_key;
if (!CBS_get_asn1(&session, &session_id, CBS_ASN1_OCTETSTRING) ||
CBS_len(&session_id) > SSL3_MAX_SSL_SESSION_ID_LENGTH ||
!CBS_get_asn1(&session, &master_key, CBS_ASN1_OCTETSTRING) ||
CBS_len(&master_key) > SSL_MAX_MASTER_KEY_LENGTH) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
OPENSSL_memcpy(ret->session_id, CBS_data(&session_id), CBS_len(&session_id));
ret->session_id_length = CBS_len(&session_id);
OPENSSL_memcpy(ret->master_key, CBS_data(&master_key), CBS_len(&master_key));
ret->master_key_length = CBS_len(&master_key);
CBS child;
uint64_t timeout;
if (!CBS_get_asn1(&session, &child, kTimeTag) ||
!CBS_get_asn1_uint64(&child, &ret->time) ||
!CBS_get_asn1(&session, &child, kTimeoutTag) ||
!CBS_get_asn1_uint64(&child, &timeout) ||
timeout > UINT32_MAX) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
ret->timeout = (uint32_t)timeout;
CBS peer;
int has_peer;
if (!CBS_get_optional_asn1(&session, &peer, &has_peer, kPeerTag) ||
(has_peer && CBS_len(&peer) == 0)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
/* |peer| is processed with the certificate chain. */
if (!SSL_SESSION_parse_bounded_octet_string(
&session, ret->sid_ctx, &ret->sid_ctx_length, sizeof(ret->sid_ctx),
kSessionIDContextTag) ||
!SSL_SESSION_parse_long(&session, &ret->verify_result, kVerifyResultTag,
X509_V_OK) ||
!SSL_SESSION_parse_string(&session, &ret->tlsext_hostname,
kHostNameTag) ||
!SSL_SESSION_parse_string(&session, &ret->psk_identity,
kPSKIdentityTag) ||
!SSL_SESSION_parse_u32(&session, &ret->tlsext_tick_lifetime_hint,
kTicketLifetimeHintTag, 0) ||
!SSL_SESSION_parse_octet_string(&session, &ret->tlsext_tick,
&ret->tlsext_ticklen, kTicketTag)) {
goto err;
}
if (CBS_peek_asn1_tag(&session, kPeerSHA256Tag)) {
CBS peer_sha256;
if (!CBS_get_asn1(&session, &child, kPeerSHA256Tag) ||
!CBS_get_asn1(&child, &peer_sha256, CBS_ASN1_OCTETSTRING) ||
CBS_len(&peer_sha256) != sizeof(ret->peer_sha256) ||
CBS_len(&child) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
OPENSSL_memcpy(ret->peer_sha256, CBS_data(&peer_sha256),
sizeof(ret->peer_sha256));
ret->peer_sha256_valid = 1;
} else {
ret->peer_sha256_valid = 0;
}
if (!SSL_SESSION_parse_bounded_octet_string(
&session, ret->original_handshake_hash,
&ret->original_handshake_hash_len,
sizeof(ret->original_handshake_hash), kOriginalHandshakeHashTag) ||
!SSL_SESSION_parse_octet_string(
&session, &ret->tlsext_signed_cert_timestamp_list,
&ret->tlsext_signed_cert_timestamp_list_length,
kSignedCertTimestampListTag) ||
!SSL_SESSION_parse_octet_string(
&session, &ret->ocsp_response, &ret->ocsp_response_length,
kOCSPResponseTag)) {
goto err;
}
int extended_master_secret;
if (!CBS_get_optional_asn1_bool(&session, &extended_master_secret,
kExtendedMasterSecretTag,
0 /* default to false */)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
ret->extended_master_secret = !!extended_master_secret;
if (!SSL_SESSION_parse_u16(&session, &ret->group_id, kGroupIDTag, 0)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
CBS cert_chain;
CBS_init(&cert_chain, NULL, 0);
int has_cert_chain;
if (!CBS_get_optional_asn1(&session, &cert_chain, &has_cert_chain,
kCertChainTag) ||
(has_cert_chain && CBS_len(&cert_chain) == 0)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
if (has_cert_chain && !has_peer) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
if (has_peer || has_cert_chain) {
ret->certs = sk_CRYPTO_BUFFER_new_null();
if (ret->certs == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
if (has_peer) {
/* TODO(agl): this should use the |SSL_CTX|'s pool. */
CRYPTO_BUFFER *buffer = CRYPTO_BUFFER_new_from_CBS(&peer, pool);
if (buffer == NULL ||
!sk_CRYPTO_BUFFER_push(ret->certs, buffer)) {
CRYPTO_BUFFER_free(buffer);
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
}
while (CBS_len(&cert_chain) > 0) {
CBS cert;
if (!CBS_get_any_asn1_element(&cert_chain, &cert, NULL, NULL) ||
CBS_len(&cert) == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
/* TODO(agl): this should use the |SSL_CTX|'s pool. */
CRYPTO_BUFFER *buffer = CRYPTO_BUFFER_new_from_CBS(&cert, pool);
if (buffer == NULL ||
!sk_CRYPTO_BUFFER_push(ret->certs, buffer)) {
CRYPTO_BUFFER_free(buffer);
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
}
}
if (!x509_method->session_cache_objects(ret)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
CBS age_add;
int age_add_present;
if (!CBS_get_optional_asn1_octet_string(&session, &age_add, &age_add_present,
kTicketAgeAddTag) ||
(age_add_present &&
!CBS_get_u32(&age_add, &ret->ticket_age_add)) ||
CBS_len(&age_add) != 0) {
goto err;
}
ret->ticket_age_add_valid = age_add_present;
int is_server;
if (!CBS_get_optional_asn1_bool(&session, &is_server, kIsServerTag,
1 /* default to true */)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
/* TODO: in time we can include |is_server| for servers too, then we can
enforce that client and server sessions are never mixed up. */
ret->is_server = is_server;
if (!SSL_SESSION_parse_u16(&session, &ret->peer_signature_algorithm,
kPeerSignatureAlgorithmTag, 0) ||
!SSL_SESSION_parse_u32(&session, &ret->ticket_max_early_data,
kTicketMaxEarlyDataTag, 0) ||
!SSL_SESSION_parse_u32(&session, &ret->auth_timeout, kAuthTimeoutTag,
ret->timeout) ||
!SSL_SESSION_parse_octet_string(&session, &ret->early_alpn,
&ret->early_alpn_len, kEarlyALPNTag) ||
CBS_len(&session) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
goto err;
}
return ret;
err:
SSL_SESSION_free(ret);
return NULL;
}
MONO_API int
mono_btls_ssl_ctx_set_ciphers (MonoBtlsSslCtx *ctx, int count, const uint16_t *data,
int allow_unsupported)
{
STACK_OF(SSL_CIPHER) *ciphers = NULL;
struct ssl_cipher_preference_list_st *pref_list = NULL;
uint8_t *in_group_flags = NULL;
int i;
ciphers = sk_SSL_CIPHER_new_null ();
if (!ciphers)
goto err;
for (i = 0; i < count; i++) {
const SSL_CIPHER *cipher = SSL_get_cipher_by_value (data [i]);
if (!cipher) {
debug_printf (ctx, "mono_btls_ssl_ctx_set_ciphers(): unknown cipher %02x", data [i]);
if (!allow_unsupported)
goto err;
continue;
}
if (!sk_SSL_CIPHER_push (ciphers, cipher))
goto err;
}
pref_list = OPENSSL_malloc (sizeof (struct ssl_cipher_preference_list_st));
if (!pref_list)
goto err;
memset (pref_list, 0, sizeof (struct ssl_cipher_preference_list_st));
pref_list->ciphers = sk_SSL_CIPHER_dup (ciphers);
if (!pref_list->ciphers)
goto err;
pref_list->in_group_flags = OPENSSL_malloc (sk_SSL_CIPHER_num (ciphers));
if (!pref_list->in_group_flags)
goto err;
if (ctx->ctx->cipher_list)
ssl_cipher_preference_list_free (ctx->ctx->cipher_list);
if (ctx->ctx->cipher_list_by_id)
sk_SSL_CIPHER_free (ctx->ctx->cipher_list_by_id);
if (ctx->ctx->cipher_list_tls10) {
ssl_cipher_preference_list_free (ctx->ctx->cipher_list_tls10);
ctx->ctx->cipher_list_tls10 = NULL;
}
if (ctx->ctx->cipher_list_tls11) {
ssl_cipher_preference_list_free (ctx->ctx->cipher_list_tls11);
ctx->ctx->cipher_list_tls11 = NULL;
}
ctx->ctx->cipher_list = pref_list;
ctx->ctx->cipher_list_by_id = ciphers;
return (int)sk_SSL_CIPHER_num (ciphers);
err:
sk_SSL_CIPHER_free (ciphers);
OPENSSL_free (pref_list);
OPENSSL_free (in_group_flags);
return 0;
}
static enum ssl_hs_wait_t do_select_parameters(SSL *ssl, SSL_HANDSHAKE *hs) {
if (!ssl->s3->session_reused) {
/* Call |cert_cb| to update server certificates if required. */
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_select_parameters;
return ssl_hs_x509_lookup;
}
}
}
struct ssl_early_callback_ctx client_hello;
if (!ssl_early_callback_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
if (!ssl->s3->session_reused) {
const SSL_CIPHER *cipher =
ssl3_choose_cipher(ssl, &client_hello, ssl_get_cipher_preferences(ssl));
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->s3->new_session->cipher = cipher;
ssl->s3->tmp.new_cipher = cipher;
} else {
uint16_t resumption_cipher;
if (!ssl_cipher_get_ecdhe_psk_cipher(ssl->s3->new_session->cipher,
&resumption_cipher)) {
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->s3->tmp.new_cipher = SSL_get_cipher_by_value(resumption_cipher);
}
ssl->method->received_flight(ssl);
/* The PRF hash is now known. Set up the key schedule and hash the
* ClientHello. */
size_t resumption_ctx_len =
EVP_MD_size(ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl)));
if (ssl->s3->session_reused) {
uint8_t resumption_ctx[EVP_MAX_MD_SIZE];
if (!tls13_resumption_context(ssl, resumption_ctx, resumption_ctx_len,
ssl->s3->new_session) ||
!tls13_init_key_schedule(ssl, resumption_ctx, resumption_ctx_len)) {
return ssl_hs_error;
}
} else {
if (!tls13_init_key_schedule(ssl, kZeroes, resumption_ctx_len)) {
return ssl_hs_error;
}
}
/* Resolve PSK and incorporate it into the secret. */
if (!resolve_psk_secret(ssl)) {
return ssl_hs_error;
}
/* Resolve ECDHE and incorporate it into the secret. */
int need_retry;
if (!resolve_ecdhe_secret(ssl, &need_retry, &client_hello)) {
if (need_retry) {
hs->state = state_send_hello_retry_request;
return ssl_hs_ok;
}
return ssl_hs_error;
}
hs->state = state_send_server_hello;
return ssl_hs_ok;
}
