Fix for BUG#16777: Can not create trigger nor view w/o definer

if --skip-grant-tables specified.

The problem is that there is a check that prevents creating a definer
with empty host name.

In --skip-grant-tables mode this check prevents the user from creating a
trigger/view without explicitly specifying its definer. This happens, because
in --skip-grant-tables mode CURRENT_USER is ''@''. According to Sanja this
check was implemented intentionally.

However, according to the MySQL manual it is possible to specify empty host
name (as well as empty user name). Moreover, the behaviour for stored routines
is different in this aspect -- we allow them to be created with implicit
definer.

Based on this, we believe it is OK to change the behaviour for views to be
similar with the behaviour for stored routines.


mysql-test/r/skip_grants.result:
  Added a test case for BUG#16777.
mysql-test/t/skip_grants.test:
  Added a test case for BUG#16777.
sql/mysql_priv.h:
  Do not check that strlen(host) > 0 in get_default_definer().
sql/sql_parse.cc:
  Do not check that strlen(host) > 0 in get_default_definer().
sql/sql_view.cc:
  Do not check that strlen(host) > 0 in get_default_definer().

mysql-test/r/skip_grants.result

@@ -2,13 +2,26 @@ drop table if exists t1,v1;
 drop view if exists t1,v1;
 drop procedure if exists f1;
 use test;
-create table t1 (field1 INT);
-CREATE VIEW v1 AS SELECT field1 FROM t1;
-ERROR HY000: Definer is not fully qualified
-drop table t1;
 create procedure f1() select 1;
 drop procedure f1;
 create table t1 (a int);
 create definer='user'@'host' sql security definer view v1 as select * from t1;
 drop view v1;
 drop table t1;
+DROP VIEW IF EXISTS v1;
+DROP VIEW IF EXISTS v2;
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1(c INT);
+CREATE TRIGGER t1_bi BEFORE INSERT ON t1
+FOR EACH ROW
+SET @a = 1;
+CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE DEFINER=a@b TRIGGER ti_ai AFTER INSERT ON t1
+FOR EACH ROW
+SET @b = 1;
+CREATE DEFINER=a@b VIEW v2 AS SELECT * FROM t1;
+DROP TRIGGER t1_bi;
+DROP TRIGGER ti_ai;
+DROP VIEW v1;
+DROP VIEW v2;
+DROP TABLE t1;

mysql-test/t/skip_grants.test

@@ -8,14 +8,6 @@ drop procedure if exists f1;
 --enable_warnings
 use test;
 
-#
-# test that we can create VIEW if privileges check switched off
-#
-create table t1 (field1 INT);
--- error ER_MALFORMED_DEFINER
-CREATE VIEW v1 AS SELECT field1 FROM t1;
-drop table t1;
-
 #
 # Test that we can create and drop procedure without warnings
 # see bug#9993
@@ -30,3 +22,48 @@ create table t1 (a int);
 create definer='user'@'host' sql security definer view v1 as select * from t1;
 drop view v1;
 drop table t1;
+
+#
+# BUG#16777: Can not create trigger nor view w/o definer if --skip-grant-tables
+# specified
+#
+# Also, a test that we can create VIEW if privileges check switched off has
+# been moved here.
+#
+
+# Prepare.
+
+--disable_warnings
+
+DROP VIEW IF EXISTS v1;
+DROP VIEW IF EXISTS v2;
+
+DROP TABLE IF EXISTS t1;
+
+--enable_warnings
+
+# Test case.
+
+CREATE TABLE t1(c INT);
+
+CREATE TRIGGER t1_bi BEFORE INSERT ON t1
+  FOR EACH ROW
+    SET @a = 1;
+
+CREATE VIEW v1 AS SELECT * FROM t1;
+
+CREATE DEFINER=a@b TRIGGER ti_ai AFTER INSERT ON t1
+  FOR EACH ROW
+    SET @b = 1;
+
+CREATE DEFINER=a@b VIEW v2 AS SELECT * FROM t1;
+
+# Cleanup.
+
+DROP TRIGGER t1_bi;
+DROP TRIGGER ti_ai;
+
+DROP VIEW v1;
+DROP VIEW v2;
+
+DROP TABLE t1;

sql/mysql_priv.h

@@ -530,7 +530,7 @@ bool insert_precheck(THD *thd, TABLE_LIST *tables);
 bool create_table_precheck(THD *thd, TABLE_LIST *tables,
                            TABLE_LIST *create_table);
 
-bool get_default_definer(THD *thd, LEX_USER *definer);
+void get_default_definer(THD *thd, LEX_USER *definer);
 LEX_USER *create_default_definer(THD *thd);
 LEX_USER *create_definer(THD *thd, LEX_STRING *user_name, LEX_STRING *host_name);
 

sql/sql_parse.cc

@@ -7168,47 +7168,28 @@ Item *negate_expression(THD *thd, Item *expr)
 
 /*
   Set the specified definer to the default value, which is the current user in
-  the thread. Also check that the current user satisfies to the definers
-  requirements.
+  the thread.
  
   SYNOPSIS
     get_default_definer()
     thd       [in] thread handler
     definer   [out] definer
- 
-  RETURN
-    error status, that is:
-      - FALSE -- on success;
-      - TRUE -- on error (current user can not be a definer).
 */
  
-bool get_default_definer(THD *thd, LEX_USER *definer)
+void get_default_definer(THD *thd, LEX_USER *definer)
 {
-  /* Check that current user has non-empty host name. */
-
   const Security_context *sctx= thd->security_ctx;
 
-  if (sctx->priv_host[0] == 0)
-  {
-    my_error(ER_MALFORMED_DEFINER, MYF(0));
-    return TRUE;
-  }
-
-  /* Fill in. */
-
   definer->user.str= (char *) sctx->priv_user;
   definer->user.length= strlen(definer->user.str);
 
   definer->host.str= (char *) sctx->priv_host;
   definer->host.length= strlen(definer->host.str);
-
-  return FALSE;
 }
 
 
 /*
-  Create default definer for the specified THD. Also check that the current
-  user is conformed to the definers requirements.
+  Create default definer for the specified THD.
 
   SYNOPSIS
     create_default_definer()
@@ -7227,8 +7208,7 @@ LEX_USER *create_default_definer(THD *thd)
   if (! (definer= (LEX_USER*) thd->alloc(sizeof(LEX_USER))))
     return 0;
 
-  if (get_default_definer(thd, definer))
-    return 0;
+  get_default_definer(thd, definer);
 
   return definer;
 }

sql/sql_view.cc

@@ -835,8 +835,7 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table)
     push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                         ER_VIEW_FRM_NO_USER, ER(ER_VIEW_FRM_NO_USER),
                         table->db, table->table_name);
-    if (get_default_definer(thd, &table->definer))
-      goto err;
+    get_default_definer(thd, &table->definer);
   }
 
   /*