fix various issues

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 7be69fa..49ca7f0 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1501,7 +1501,7 @@
                 MBEDTLS_SSL_DEBUG_MSG(
                     3, ( "unsupported extension found: %u ", extension_type) );
                 MBEDTLS_SSL_PEND_FATAL_ALERT(
-                    MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT,   \
+                    MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT,
                     MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
                 return ( MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
         }
@@ -1513,7 +1513,7 @@
     if( p != end )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension lengths misaligned" ) );
-        MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,   \
+        MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
                                       MBEDTLS_ERR_SSL_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_DECODE_ERROR );
     }
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 026c94c..598b2bc 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -271,7 +271,7 @@
 
     MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 4 );
     certificate_request_context_len = p[0];
-    certificate_list_len = ( p[1] << 16 ) | ( p[2] << 8 ) | p[3];
+    certificate_list_len = MBEDTLS_GET_UINT24_BE( p, 0 );
     p += 4;
 
     /* In theory, the certificate list can be up to 2^24 Bytes, but we don't