dr_47: add boundary checking

src/descriptors/dr_47.c

@@ -65,7 +65,10 @@ dvbpsi_bouquet_name_dr_t * dvbpsi_DecodeBouquetNameDr(
 
     /* Decode data */
     p_decoded->i_name_length = p_descriptor->i_length;
-    if(p_decoded->i_name_length)
+    if (p_decoded->i_name_length > 255)
+        p_decoded->i_name_length = 255;
+
+    if (p_decoded->i_name_length)
         memcpy(p_decoded->i_char,
                p_descriptor->p_data,
                p_decoded->i_name_length);
@@ -82,6 +85,9 @@ dvbpsi_bouquet_name_dr_t * dvbpsi_DecodeBouquetNameDr(
 dvbpsi_descriptor_t * dvbpsi_GenBouquetNameDr(dvbpsi_bouquet_name_dr_t *p_decoded,
                                         bool b_duplicate)
 {
+    if (p_decoded->i_name_length > 255)
+        p_decoded->i_name_length = 255;
+
     /* Create the descriptor */
     dvbpsi_descriptor_t * p_descriptor =
             dvbpsi_NewDescriptor(0x47, p_decoded->i_name_length, NULL);