Add compute early transform
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 1b76996..f179181 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -1081,6 +1081,156 @@
return 0;
}
+#if defined(MBEDTLS_SSL_EARLY_DATA)
+/* ssl_tls13_generate_early_keys() generates keys necessary for protecting
+ * the early app data messages described in section 7 RFC 8446. */
+MBEDTLS_CHECK_RETURN_CRITICAL
+static int ssl_tls13_generate_early_keys( mbedtls_ssl_context *ssl,
+ mbedtls_ssl_key_set *traffic_keys )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+ mbedtls_md_type_t md_type;
+
+ psa_algorithm_t hash_alg;
+ size_t hash_len;
+
+ unsigned char transcript[MBEDTLS_TLS1_3_MD_MAX_SIZE];
+ size_t transcript_len;
+
+ size_t key_len, iv_len;
+
+ mbedtls_ssl_handshake_params *handshake = ssl->handshake;
+ const mbedtls_ssl_ciphersuite_t *ciphersuite_info = handshake->ciphersuite_info;
+ mbedtls_ssl_tls13_early_secrets *tls13_early_secrets = &handshake->tls13_early_secrets;
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_tls13_generate_early_keys" ) );
+
+ ret = ssl_tls13_get_cipher_key_info( ciphersuite_info, &key_len, &iv_len );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_get_cipher_key_info", ret );
+ return ret;
+ }
+
+ md_type = ciphersuite_info->mac;
+
+ hash_alg = mbedtls_hash_info_psa_from_md( ciphersuite_info->mac );
+ hash_len = PSA_HASH_LENGTH( hash_alg );
+
+ ret = mbedtls_ssl_get_handshake_transcript( ssl, md_type,
+ transcript,
+ sizeof( transcript ),
+ &transcript_len );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1,
+ "mbedtls_ssl_get_handshake_transcript",
+ ret );
+ return( ret );
+ }
+
+ ret = mbedtls_ssl_tls13_derive_early_secrets( hash_alg,
+ handshake->tls13_master_secrets.early,
+ transcript, transcript_len, tls13_early_secrets );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET(
+ 1, "mbedtls_ssl_tls13_derive_early_secrets", ret );
+ return( ret );
+ }
+
+ MBEDTLS_SSL_DEBUG_BUF(
+ 4, "Client early traffic secret",
+ tls13_early_secrets->client_early_traffic_secret,
+ hash_len );
+
+ /*
+ * Export client handshake traffic secret
+ */
+ if( ssl->f_export_keys != NULL )
+ {
+ ssl->f_export_keys( ssl->p_export_keys,
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_EARLY_SECRET,
+ tls13_early_secrets->client_early_traffic_secret,
+ hash_len,
+ handshake->randbytes,
+ handshake->randbytes + MBEDTLS_CLIENT_HELLO_RANDOM_LEN,
+ MBEDTLS_SSL_TLS_PRF_NONE /* TODO: FIX! */ );
+ }
+
+ ret = mbedtls_ssl_tls13_make_traffic_keys( hash_alg,
+ tls13_early_secrets->client_early_traffic_secret,
+ tls13_early_secrets->client_early_traffic_secret,
+ hash_len, key_len, iv_len, traffic_keys );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_make_traffic_keys", ret );
+ goto exit;
+ }
+
+ MBEDTLS_SSL_DEBUG_BUF( 5, "client_handshake write_key",
+ traffic_keys->client_write_key,
+ traffic_keys->key_len);
+
+ MBEDTLS_SSL_DEBUG_BUF( 5, "client_handshake write_iv",
+ traffic_keys->client_write_iv,
+ traffic_keys->iv_len);
+
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_tls13_generate_early_keys" ) );
+
+exit:
+
+ return( ret );
+}
+
+int mbedtls_ssl_tls13_compute_early_transform( mbedtls_ssl_context *ssl )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ mbedtls_ssl_key_set traffic_keys;
+ mbedtls_ssl_transform *transform_earlydata = NULL;
+ mbedtls_ssl_handshake_params *handshake = ssl->handshake;
+
+ /* Next evolution in key schedule: Establish early_data secret and
+ * key material. */
+ ret = ssl_tls13_generate_early_keys( ssl, &traffic_keys );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_generate_early_keys",
+ ret );
+ goto cleanup;
+ }
+
+ transform_earlydata = mbedtls_calloc( 1, sizeof( mbedtls_ssl_transform ) );
+ if( transform_earlydata == NULL )
+ {
+ ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+ goto cleanup;
+ }
+
+ ret = mbedtls_ssl_tls13_populate_transform(
+ transform_earlydata,
+ ssl->conf->endpoint,
+ ssl->session_negotiate->ciphersuite,
+ &traffic_keys,
+ ssl );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_populate_transform", ret );
+ goto cleanup;
+ }
+ handshake->transform_earlydata = transform_earlydata;
+
+cleanup:
+ mbedtls_platform_zeroize( &traffic_keys, sizeof( traffic_keys ) );
+ if( ret != 0 )
+ mbedtls_free( transform_earlydata );
+
+ return( ret );
+}
+#endif /* MBEDTLS_SSL_EARLY_DATA */
+
int mbedtls_ssl_tls13_key_schedule_stage_early( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;