commit 8bee89994dbcc119812ac81102eb22e959cf9093
author Xiaokang Qian <xiaokang.qian@arm.com> Thu Oct 27 10:21:05 2022 +0000
committer Xiaokang Qian <xiaokang.qian@arm.com> Tue Nov 22 09:40:07 2022 +0000
tree 9161f0f2164d7cbb9382b5932d11c339d5c939df
parent 339406daf925746f88e5c5af1a8eb51c4d799c1c

Add parse function for early data in encrypted extentions

Signed-off-by: Xiaokang Qian <xiaokang.qian@arm.com>

library/ssl_tls13_client.c

diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 0372f2d..839fe36 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1335,6 +1335,53 @@
     return( 0 );
 }
 
+#if defined(MBEDTLS_SSL_EARLY_DATA)
+/*
+ * ssl_tls13_parse_ee_early_data_ext()
+ *      Parse early data indication extension in EncryptedExtensions.
+ *
+ * struct {} Empty;
+ *
+ * struct {
+ *   select (Handshake.msg_type) {
+ *     ...
+ *     case client_hello:         Empty;
+ *     case encrypted_extensions: Empty;
+ *   };
+ * } EarlyDataIndication;
+ *
+ */
+
+MBEDTLS_CHECK_RETURN_CRITICAL
+static int ssl_tls13_parse_ee_early_data_ext( mbedtls_ssl_context *ssl,
+                                              const unsigned char *buf,
+                                              size_t len )
+{
+    if( ssl->early_data_status < MBEDTLS_SSL_EARLY_DATA_STATUS_INDICATION_SENT )
+    {
+        /* The server must not send the EarlyDataIndication if the
+         * client hasn't indicated the use of early data. */
+        MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
+                                      MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
+        return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
+    }
+
+    if( len != 0 )
+    {
+        /* The message must be empty. */
+        MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
+                                      MBEDTLS_ERR_SSL_DECODE_ERROR );
+        return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+    }
+
+    /* Nothing to parse */
+    ((void) buf);
+
+    ssl->early_data_status = MBEDTLS_SSL_EARLY_DATA_STATUS_ACCEPTED;
+    return( 0 );
+}
+#endif /* MBEDTLS_SSL_EARLY_DATA */
+
 /* Returns a negative value on failure, and otherwise
  * - SSL_SERVER_HELLO or
  * - SSL_SERVER_HELLO_HRR
@@ -2060,6 +2107,22 @@
 
                 break;
 #endif /* MBEDTLS_SSL_ALPN */
+
+#if defined(MBEDTLS_SSL_EARLY_DATA)
+            case MBEDTLS_TLS_EXT_EARLY_DATA:
+                ret = ssl_tls13_parse_ee_early_data_ext(
+                            ssl, p, (size_t)extension_data_len );
+                if( ret != 0 )
+                {
+                    ssl->early_data_status =
+                            MBEDTLS_SSL_EARLY_DATA_STATUS_REJECTED;
+                    MBEDTLS_SSL_DEBUG_RET(
+                            1, "ssl_tls13_parse_ee_early_data_ext", ret );
+                    return( ret );
+                }
+                break;
+#endif /* MBEDTLS_SSL_EARLY_DATA */
+
             default:
                 MBEDTLS_SSL_PRINT_EXT(
                     3, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS,