Fixed bug mdev-13453 Executing a query via CTE requires more permissions

than the query itself

ACL checks were not properly supported for tables used in CTE
specifications. This patch fixes the problem.

mysql-test/r/cte_nonrecursive.result

@@ -1147,3 +1147,61 @@ SELECT * FROM cte_test;
 a
 1
 DROP VIEW cte_test;
+#
+# MDEV-13453: privileges checking for CTE
+#
+create database db;
+use db;
+create table t1 (i int);
+insert into t1
+values (3), (7), (1), (4), (2), (3), (1);
+create table t2 (a int, b int);
+insert into t2
+values (3,10), (7,11), (1,17), (4,15), (2,11), (3,10), (1,15);
+create user foo@localhost;
+grant SELECT on db.t1 to foo@localhost;
+grant SELECT(a) on db.t2 to foo@localhost;
+connect  con1,localhost,foo,,;
+use db;
+with cte as (select * from t1 where i < 4)
+select * from cte;
+i
+3
+1
+2
+3
+1
+with cte as (select * from t1 where i < 4 group by i)
+select * from cte;
+i
+1
+2
+3
+with cte as (select * from t1 where i < 4)
+select * from cte cte1 where i < 2 union select * from cte cte2 where i > 2;
+i
+1
+3
+with cte as (select * from t1 where i < 4 group by i)
+select * from cte cte1 where i < 2 union select * from cte cte2 where i > 2;
+i
+1
+3
+with cte as (select b from t2 where a < 4)
+select * from cte cte1 where b < 15 union select * from cte cte2 where b > 15;
+ERROR 42000: SELECT command denied to user 'foo'@'localhost' for column 'b' in table 't2'
+with cte as (select a from t2 where a < 4)
+select * from cte cte1 where a < 2 union select * from cte cte2 where a > 2;
+a
+1
+3
+connection default;
+revoke SELECT on db.t1 from foo@localhost;
+connection con1;
+with cte as (select * from t1 where i < 4)
+select * from cte;
+ERROR 42000: SELECT command denied to user 'foo'@'localhost' for table 't1'
+disconnect con1;
+connection default;
+drop database db;
+drop user foo@localhost;

mysql-test/t/cte_nonrecursive.test

@@ -790,3 +790,54 @@ SHOW CREATE VIEW cte_test;
 SELECT * FROM cte_test;
 
 DROP VIEW cte_test;
+
+--echo #
+--echo # MDEV-13453: privileges checking for CTE
+--echo #
+
+create database db;
+use db;
+create table t1 (i int);
+insert into t1
+  values (3), (7), (1), (4), (2), (3), (1);
+
+create table t2 (a int, b int);
+insert into t2
+  values (3,10), (7,11), (1,17), (4,15), (2,11), (3,10), (1,15);
+
+create user foo@localhost;
+grant SELECT on db.t1 to foo@localhost;
+grant SELECT(a) on db.t2 to foo@localhost;
+
+--connect (con1,localhost,foo,,)
+use db;
+with cte as (select * from t1 where i < 4)
+  select * from cte;
+with cte as (select * from t1 where i < 4 group by i)
+  select * from cte;
+with cte as (select * from t1 where i < 4)
+  select * from cte cte1 where i < 2 union select * from cte cte2 where i > 2;
+with cte as (select * from t1 where i < 4 group by i)
+  select * from cte cte1 where i < 2 union select * from cte cte2 where i > 2;
+
+--error ER_COLUMNACCESS_DENIED_ERROR
+with cte as (select b from t2 where a < 4)
+  select * from cte cte1 where b < 15 union select * from cte cte2 where b > 15;
+with cte as (select a from t2 where a < 4)
+  select * from cte cte1 where a < 2 union select * from cte cte2 where a > 2;
+
+--connection default
+revoke SELECT on db.t1 from foo@localhost;
+
+--connection con1
+
+--error ER_TABLEACCESS_DENIED_ERROR
+with cte as (select * from t1 where i < 4)
+  select * from cte;
+
+# Cleanup
+--disconnect con1
+
+--connection default
+drop database db;
+drop user foo@localhost;

sql/sql_acl.cc

@@ -7557,6 +7557,10 @@ bool check_grant(THD *thd, ulong want_access, TABLE_LIST *tables,
       tl->correspondent_table ? tl->correspondent_table : tl;
     sctx= t_ref->security_ctx ? t_ref->security_ctx : thd->security_ctx;
 
+    if (tl->with ||
+        (tl->with= tl->select_lex->find_table_def_in_with_clauses(tl)))
+      continue;
+
     const ACL_internal_table_access *access=
       get_cached_table_access(&t_ref->grant.m_internal,
                               t_ref->get_db_name(),

sql/sql_cte.cc

@@ -823,9 +823,10 @@ st_select_lex_unit *With_element::clone_parsed_spec(THD *thd,
        tbl;
        tbl= tbl->next_global)
   {
-    tbl->grant.privilege= with_table->grant.privilege;
     spec_tables_tail= tbl;
   }
+  if (check_table_access(thd, SELECT_ACL, spec_tables, FALSE, UINT_MAX, FALSE))
+    goto err;
   if (spec_tables)
   {
     if (with_table->next_global)

sql/sql_parse.cc

@@ -3443,6 +3443,14 @@ mysql_execute_command(THD *thd)
     ulong privileges_requested= lex->exchange ? SELECT_ACL | FILE_ACL :
       SELECT_ACL;
 
+    /* 
+      The same function must be called for DML commands
+      when CTEs are supported in DML statements
+    */
+    res= check_dependencies_in_with_clauses(thd->lex->with_clauses_list);
+    if (res)
+      break;
+
     if (all_tables)
       res= check_table_access(thd,
                               privileges_requested,