Fixed CORE-2888 - A memory corruption cause incorrect query evaluatio…

…n and may crash the server
FirebirdSQL · Feb 26, 2010 · 0829b12 · 0829b12
1 parent 9b432cc
commit 0829b12
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/src/dsql/pass1.cpp b/src/dsql/pass1.cpp
@@ -6239,13 +6239,19 @@ static dsql_nod* pass1_make_derived_field(DsqlCompilerScratch* dsqlScratch, thre
 				return select_item;
 			}
 
-		case nod_via :
+		case nod_via:
 			{
 				// Try to generate derived field from sub-select
 				dsql_nod* derived_field = pass1_make_derived_field(dsqlScratch, tdbb,
 					select_item->nod_arg[e_via_value_1]);
-				derived_field->nod_arg[e_derived_field_value] = select_item;
-				return derived_field;
+
+				if (derived_field->nod_type == nod_derived_field)
+				{
+					derived_field->nod_arg[e_derived_field_value] = select_item;
+					return derived_field;
+				}
+
+				return select_item;
 			}
 
 		default: