MDEV-15947 ASAN heap-use-after-free in Item_ident::print or in...

MDEV-15947 ASAN heap-use-after-free in Item_ident::print or in my_strcasecmp_utf8 or unexpected ER_BAD_FIELD_ERROR upon call of stored procedure reading from versioned table

Closes #728

mysql-test/suite/versioning/r/select.result

@@ -557,6 +557,18 @@ i
 call p(3);
 i
 1
+#
+# MDEV-15947 ASAN heap-use-after-free in Item_ident::print or in my_strcasecmp_utf8 or unexpected ER_BAD_FIELD_ERROR upon call of stored procedure reading from versioned table
+#
+create or replace table t1 (i int) with system versioning;
+create or replace procedure p() select * from t1;
+call p;
+i
+flush tables;
+call p;
+i
+call p;
+i
 drop procedure p;
 drop table t1;
 call verify_trt_dummy(34);

mysql-test/suite/versioning/t/select.test

@@ -363,6 +363,16 @@ call p(1);
 alter table t1 add system versioning;
 call p(2);
 call p(3);
+
+--echo #
+--echo # MDEV-15947 ASAN heap-use-after-free in Item_ident::print or in my_strcasecmp_utf8 or unexpected ER_BAD_FIELD_ERROR upon call of stored procedure reading from versioned table
+--echo #
+create or replace table t1 (i int) with system versioning;
+create or replace procedure p() select * from t1;
+call p;
+flush tables;
+call p;
+call p;
 drop procedure p;
 drop table t1;
 

sql/sql_class.h

@@ -3669,6 +3669,10 @@ class THD :public Statement,
     lex_str->length= length;
     return lex_str;
   }
+  LEX_CSTRING *make_clex_string(const LEX_CSTRING from)
+  {
+    return make_clex_string(from.str, from.length);
+  }
 
   // Allocate LEX_STRING for character set conversion
   bool alloc_lex_string(LEX_STRING *dst, size_t length)

sql/sql_select.cc

@@ -822,8 +822,10 @@ int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables)
       lock_type= TL_READ; // ignore TL_WRITE, history is immutable anyway
     }
 
-    const LEX_CSTRING *fstart= &table->table->vers_start_field()->field_name;
-    const LEX_CSTRING *fend= &table->table->vers_end_field()->field_name;
+    const LEX_CSTRING *fstart=
+        thd->make_clex_string(table->table->vers_start_field()->field_name);
+    const LEX_CSTRING *fend=
+        thd->make_clex_string(table->table->vers_end_field()->field_name);
 
     Item *row_start=
         newx Item_field(thd, &this->context, table->db.str, table->alias.str, fstart);