MDEV-7574 Security definer views don't work with CONNECT ODBC tables

Instead of checking user's privileges with check_access(),
use the cached value in table->grant.privilege instead -
it is correctly set to the invoker or definer, depending
on SQL SECURITY mode.

Continue to use check_access() for DDLs when
table->grant.privilege may be not set (but these cases are
only possible on tables, never for views).

(patch originally by Alexander Barkov)

storage/connect/ha_connect.cc

@@ -4020,7 +4020,27 @@ bool ha_connect::check_privileges(THD *thd, PTOS options, char *dbn)
     case TAB_MAC:
     case TAB_WMI:
     case TAB_OEM:
-      return check_access(thd, FILE_ACL, db, NULL, NULL, 0, 0);
+#ifdef NO_EMBEDDED_ACCESS_CHECKS
+      return false;
+#endif
+      /*
+        If table or table->mdl_ticket is NULL - it's a DLL, e.g. CREATE TABLE.
+        if the table has an MDL_EXCLUSIVE lock - it's a DDL too, e.g. the
+        insert step of CREATE ... SELECT.
+
+        Otherwise it's a DML, the table was normally opened, locked,
+        privilege were already checked, and table->grant.privilege is set.
+        With SQL SECURITY DEFINER, table->grant.privilege has definer's privileges.
+      */
+      if (!table || !table->mdl_ticket || table->mdl_ticket->get_type() == MDL_EXCLUSIVE)
+        return check_access(thd, FILE_ACL, db, NULL, NULL, 0, 0);
+      if (table->grant.privilege & FILE_ACL)
+        return false;
+      status_var_increment(thd->status_var.access_denied_errors);
+      my_error(access_denied_error_code(thd->password), MYF(0),
+               thd->security_ctx->priv_user, thd->security_ctx->priv_host,
+               (thd->password ?  ER(ER_YES) : ER(ER_NO)));
+      return true;
 
     // This is temporary until a solution is found
     case TAB_TBL:
@@ -6159,10 +6179,6 @@ bool ha_connect::FileExists(const char *fn, bool bf)
     int   n;
     struct stat info;
 
-    if (check_access(ha_thd(), FILE_ACL, table->s->db.str,
-                     NULL, NULL, 0, 0))
-      return true;
-
 #if defined(__WIN__)
     s= "\\";
 #else   // !__WIN__

storage/connect/mysql-test/connect/r/grant.result

@@ -46,7 +46,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost
@@ -130,7 +130,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost
@@ -224,7 +224,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost
@@ -318,7 +318,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost
@@ -412,7 +412,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost
@@ -506,7 +506,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost

storage/connect/mysql-test/connect/r/ini_grant.result

@@ -59,7 +59,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost

storage/connect/mysql-test/connect/r/mysql_grant.result

@@ -40,7 +40,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost

storage/connect/mysql-test/connect/r/odbc_sqlite3_grant.result

@@ -49,10 +49,11 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 CREATE VIEW v1 AS SELECT * FROM t1;
 ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 # Testing a VIEW created with FILE privileges but accessed with no FILE
+# using SQL SECIRITY INVOKER
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost
@@ -64,6 +65,19 @@ UPDATE v1 SET a=123;
 ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 DELETE FROM v1;
 ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
+# Testing a VIEW created with FILE privileges but accessed with no FILE
+# using SQL SECIRITY DEFINER
+DROP VIEW v1;
+SELECT user();
+user()
+root@localhost
+CREATE SQL SECURITY DEFINER VIEW v1 AS SELECT * FROM t1;
+SELECT user();
+user()
+user@localhost
+SELECT * FROM v1 WHERE a='test1';
+a
+test1
 SELECT user();
 user()
 root@localhost

storage/connect/mysql-test/connect/r/xml_grant.result

@@ -63,7 +63,7 @@ ERROR 28000: Access denied for user 'user'@'localhost' (using password: NO)
 SELECT user();
 user()
 root@localhost
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 SELECT user();
 user()
 user@localhost

storage/connect/mysql-test/connect/t/grant.inc

@@ -53,7 +53,7 @@ CREATE VIEW v1 AS SELECT * FROM t1;
 --echo # Testing a VIEW created with FILE privileges but accessed with no FILE
 --connection default
 SELECT user();
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 --connection user
 SELECT user();
 --error ER_ACCESS_DENIED_ERROR

storage/connect/mysql-test/connect/t/grant.test

@@ -49,7 +49,7 @@ CREATE VIEW v1 AS SELECT * FROM t1;
 --echo # Testing a VIEW created with FILE privileges but accessed with no FILE
 --connection default
 SELECT user();
-CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1 AS SELECT * FROM t1;
 --connection user
 SELECT user();
 --error ER_ACCESS_DENIED_ERROR