Re-generating SQL Server Logins, Part 2

February 25, 2011

This is the second article on my Re-generate SQL Server login series. In my first column, I focused on server-level role and database-level role assignment for any assigned login. I also mentioned frequent DBA encountered tasks related to ensuring login properties setup and what kind of implications might be created if login permission is not properly defined. In this portion of the series, I’d like to walk through list of securables and how to generate login to include securable granting and denying.

What is a securable?

Simply put, any entity within the database engine that can be secured with permission is called securable. The highest levels of securables are servers and databases, mid-level securables are assemblies, full-text catalogs, message types, etc., and the finest level securables are table, view, function, stored procedure, etc. We can grant, deny and revoke permission on securables.

Server-level permission

Below is the list of server-level permissions. The list on the left also includes the permission defined on the right. For instance, once we grant a login control server permission, the login will also have privilege to do bulk operation, create and alter any database, create unsafe assembly and shutdown the SQL instance. We need to be extra careful when granting anyone server-level permission. One thing worth mentioning is that by default all users have permission to "VIEW ANY DATABASE." Also, to grant server-level permission, we need to be in the master database to issue the server scope granting command and we either need to be a sysadmin or possess the server-level permission and higher with GRANT option to give others permission on server level. The server-level permission information is stored on sys.server_permissions.

Server Permission	Finer Server Permission
CONTROL SERVER	ADMINISTER BULK OPERATIONS
CONTROL SERVER	ALTER ANY CONNECTION
CONTROL SERVER	ALTER ANY CREDENTIAL
CONTROL SERVER	ALTER ANY DATABASE
CONTROL SERVER	ALTER ANY ENDPOINT
CONTROL SERVER	ALTER ANY EVENT NOTIFICATION
CONTROL SERVER	ALTER ANY LINKED SERVER
CONTROL SERVER	ALTER ANY LOGIN
CONTROL SERVER	ALTER ANY SERVER AUDIT
CONTROL SERVER	ALTER RESOURCES
CONTROL SERVER	ALTER SERVER STATE
CONTROL SERVER	ALTER SETTINGS
CONTROL SERVER	ALTER TRACE
CONTROL SERVER	AUTHENTICATE SERVER
CONTROL SERVER	CONNECT SQL
CONTROL SERVER	CONTROL SERVER
CONTROL SERVER	EXTERNAL ACCESS ASSEMBLY
CONTROL SERVER	SHUTDOWN
CONTROL SERVER	UNSAFE ASSEMBLY
CONTROL SERVER	VIEW ANY DEFINITION
ALTER ANY EVENT NOTIFICATION	CREATE DDL EVENT NOTIFICATION
ALTER ANY EVENT NOTIFICATION	CREATE TRACE EVENT NOTIFICATION
ALTER ANY ENDPOINT	CREATE ENDPOINT
ALTER SERVER STATE	VIEW SERVER STATE
ALTER ANY DATABASE	CREATE ANY DATABASE
VIEW ANY DEFINITION	VIEW ANY DATABASE

Permission on database-level securable

Unlike server-level permission that you can only define when connecting to the master database, each database has its list of pre-defined class of securable that you can grant permission on database principal (database user). Here is the list of securable class on which permission exists:

Database
Object or column
Schema
Database principal
Assembly
Type
XML schema collection
Message type (Service Broker securable)
Service contract (Service Broker securable)
Service (Service Broker securable)
Remote Service Binding (Service Broker securable)
Route (Service Broker securable)
Full-Text Catalog
Symmetric Key
Certificate
Asymmetric Key

Database-level Permission information is stored on sys.database_permissions. Unless sys.server_permissions, sys.database_permissions exists for every database.

Grant, revoke and deny

The definition for GRANT, REVOKE and DENY can be confusing sometimes. Simply put, revoke is used to remove the permission that has been GRANTED or DENIED on the same securable.

But what if we grant permission to a lower scope securable and then issue DENY or REVOKE on a higher scope securable, what will happen to the lower scope securable? No surprise, there is a difference.

When Denying on a higher-level securable, the principal will be denied on the lower-level securable.

When Revoking on a higher-level securable, the principal will keep his granted permission on the lower scope securable.

A principal can grant permission to another principal if his permission is granted with grant option.

Generate script for server and database securable class

We have briefly gone over the available list of server-level and database-level securable class. We often face tasks like listing out what permission a login has. In my first article in this series, we talked about server role and database role assignment for any given login. But there are cases where login was given more specific permission that was not given through server or database role but through server and database securable. This is the most easily forgotten part of login permission.

It would be nice to simply input the login name that we are interested in and get ready to use script to recover permission on server level and database level securable for the specified principal. In this article, I am only focusing on database and server-level securables. If you are interested to see how to generate login creation, server role assignment or database role assignment, please refer to the first article of the series.

Now, we can look into the script. To use the script, here are the steps. This script works on SQL 2005, SQL 2008 and SQL 2008 R2.

1. Open Microsoft SQL Server Management Studio (a.k.a SSMS), make a connection to the SQL instance, then click New Query. Make sure the credential you use to run the code has adequate privileges to generate the script.

2. Copy below code into the query window

3. Replace 'YourloginName' with the login you would like to re-generate securable permission script, then execute

----------------------------------------------

--Login Pre-requisites

----------------------------------------------

set concat_null_yields_null off

USE master

SET NOCOUNT ON

DECLARE @login_name varchar(100)

SET @login_name = 'YourLoginName'

-----------------------------------------------------------------

IF lower(@login_name) IN ('sa','public')

BEGIN

RAISERROR (15405,11,1,@login_name)

RETURN

END

IF NOT EXISTS (SELECT * FROM sys.server_principals WHERE name = @login_name AND type IN ('G','U','S'))

BEGIN

PRINT 'Please input valid login name'

RETURN

END

DECLARE @login_sid varbinary(85)

SELECT @login_sid = sid FROM sys.server_principals WHERE name = @login_name

DECLARE @maxid int

IF OBJECT_ID('tempdb..#db_users') is not null

BEGIN

DROP TABLE #db_users

END

SELECT id = identity(int,1,1), sql_cmd = 'SELECT '''+name+''', * FROM ['+name+'].sys.database_principals' INTO #db_users FROM sys.databases

WHERE state_desc <> 'OFFLINE'

SELECT @maxid = @@ROWCOUNT

----------------------------------------------

--Create Server Role Temp table

----------------------------------------------

IF OBJECT_ID('tempdb..#srvrole') IS NOT NULL

BEGIN

DROP TABLE #srvrole

END

CREATE TABLE #srvrole(ServerRole sysname, MemberName sysname, MemberSID varbinary(85))

INSERT INTO [#srvrole] EXEC sp_helpsrvrolemember

DECLARE @login_srvrole varchar(1000)

SET @login_srvrole = ''

IF EXISTS (select * from [#srvrole] where ServerRole = 'sysadmin' AND MemberName = @login_name)

BEGIN

PRINT '--Login ['+@login_name+'] is part of sysadmin server role, hence possesses full privileges for SQL instance: '+@@servername

PRINT 'GO'

SELECT @login_srvrole = @login_srvrole + 'EXEC sp_addsrvrolemember '''+MemberName+''','''+ServerRole+''''+CHAR(10) FROM #srvrole

WHERE [MemberName] = @login_name

PRINT @login_srvrole

RETURN

END

---------------------------------------------------

--Find out list of db that the login has access to

---------------------------------------------------

PRINT ''

PRINT '----------------------------------------------'

PRINT '--Create database user for login '

PRINT '----------------------------------------------'

IF OBJECT_ID('tempdb..#alldb_users') is not null

BEGIN

DROP TABLE #alldb_users

END

CREATE TABLE #alldb_users(

[dbname] [sysname] NOT NULL,

[name] [sysname] NOT NULL,

[principal_id] [int] NOT NULL,

[type] [char](1) NOT NULL,

[type_desc] [nvarchar](60) NULL,

[default_schema_name] [sysname] NULL,

[create_date] [datetime] NOT NULL,

[modify_date] [datetime] NOT NULL,

[owning_principal_id] [int] NULL,

[sid] [varbinary](85) NULL,

[is_fixed_role] [bit] NOT NULL

)

DECLARE @id int, @sqlcmd varchar(500)

SET @id = 1

WHILE @id <=@maxid

BEGIN

SELECT @sqlcmd = sql_cmd FROM #db_users WHERE id = @id

INSERT INTO #alldb_users EXEC (@sqlcmd)

SET @id = @id + 1

END

DELETE FROM #alldb_users WHERE sid is null

DELETE FROM #alldb_users WHERE sid <> @login_sid

IF NOT EXISTS (SELECT * FROM #alldb_users )

BEGIN

PRINT '--Login ['+@login_name+'] doesnt have access to any database'

END

DECLARE @name sysname, @dbname sysname, @schema sysname, @dbuser_cmd varchar(8000)

DECLARE dbuser_cursor CURSOR FAST_FORWARD FOR

SELECT dbname, name, default_schema_name

FROM #alldb_users

OPEN dbuser_cursor

FETCH NEXT FROM dbuser_cursor INTO @dbname, @name, @schema

WHILE @@FETCH_STATUS = 0

BEGIN

IF @schema IS NOT NULL

BEGIN

SELECT @dbuser_cmd = 'USE ['+dbname+']

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = '''+name+''')

BEGIN

CREATE USER ['+@name+'] FOR LOGIN ['+@login_name+']'+isnull(' WITH DEFAULT_SCHEMA=['+default_schema_name+']','')+'

END

' FROM #alldb_users WHERE name = @name and dbname = @dbname

END

ELSE

BEGIN

SELECT @dbuser_cmd = 'USE ['+dbname+']

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = '''+name+''')

BEGIN

CREATE USER ['+@name+'] FOR LOGIN ['+@login_name+']

END

' FROM #alldb_users WHERE name = @name and dbname = @dbname

END

print @dbuser_cmd

FETCH NEXT FROM dbuser_cursor INTO @dbname, @name, @schema

END

CLOSE dbuser_cursor

DEALLOCATE dbuser_cursor

----------------------------------------------

--Create DB Role Temp table

----------------------------------------------

IF OBJECT_ID('tempdb..#dbrole') is not null

BEGIN

DROP TABLE #dbrole

END

create table #dbrole (id int identity(1,1), dbname varchar(100), dbrole varchar (100), dbrole_member varchar(100), sid varbinary(85), default_schema_name varchar(100), login_name varchar(100), db_principal_id int)

DECLARE @dbrole_sqlcmd varchar(max)

DECLARE dbrole_cursor CURSOR FAST_FORWARD FOR

SELECT

'SELECT '''+dbname+''', c.name, b.name, b.sid, b.default_schema_name, d.name, b.principal_id as login_name

from ['+dbname+'].sys.database_role_members a

inner join ['+dbname+'].sys.database_principals b on a.member_principal_id = b.principal_id

inner join ['+dbname+'].sys.database_principals c on a.role_principal_id = c.principal_id

left join sys.server_principals d on b.sid = d.sid

where d.name= '''+@login_name+''''

from #alldb_users

OPEN dbrole_cursor

FETCH NEXT FROM dbrole_cursor INTO @dbrole_sqlcmd

WHILE @@FETCH_STATUS = 0

BEGIN

INSERT INTO #dbrole (dbname, dbrole, dbrole_member, sid, default_schema_name, login_name, db_principal_id) exec(@dbrole_sqlcmd)

FETCH NEXT FROM dbrole_cursor INTO @dbrole_sqlcmd

END

CLOSE dbrole_cursor

DEALLOCATE dbrole_cursor

DELETE FROM #dbrole WHERE sid <> @login_sid

IF EXISTS (SELECT * FROM #dbrole where dbrole = 'db_owner')

BEGIN

PRINT '----------------------------------------------'

PRINT'--Login is db_owner of below databases'

PRINT'----------------------------------------------'

END

DECLARE @dbname_dbowner varchar(100), @dbrole_member varchar(100)

DECLARE dbowner_cursor CURSOR FAST_FORWARD FOR

SELECT dbname, dbrole_member from #dbrole where dbrole = 'db_owner'

OPEN dbowner_cursor

FETCH NEXT FROM dbowner_cursor INTO @dbname_dbowner, @dbrole_member

WHILE @@FETCH_STATUS = 0

BEGIN

PRINT 'USE ['+@dbname_dbowner+']

EXEC sp_addrolemember ''db_owner'','''+@dbrole_member +'''

GO'

FETCH NEXT FROM dbowner_cursor INTO @dbname_dbowner, @dbrole_member

END

CLOSE dbowner_cursor

DEALLOCATE dbowner_cursor

--------------------------------------------------------------------------------------------------------

--Find out what database the login has permission to access (avoid restricted and single user database)

--------------------------------------------------------------------------------------------------------

DELETE From #srvrole where MemberName <> @login_name

IF OBJECT_ID('tempdb..#alldb_users_access') IS NOT NULL

BEGIN

DROP TABLE #alldb_users_access

END

SELECT a.*, collation_name INTO #alldb_users_access FROM #alldb_users a inner join sys.databases b ON a.dbname = b.name

WHERE user_access = 0

(user_access = 2 and exists (SELECT * FROM #srvrole WHERE ServerRole in ('dbcreator','sysadmin')))

(user_access = 2 and a.dbname in (SELECT dbname FROM #dbrole WHERE dbrole = 'db_owner' AND login_name = @login_name))

--------------------------------------------------------------------------------------------------------

--Remove database that login doesnt have permission to connect

--------------------------------------------------------------------------------------------------------

IF OBJECT_ID('tempdb..#dbconnect') is not null

BEGIN

DROP TABLE #dbconnect

END

CREATE TABLE #dbconnect ( dbname varchar(100), connect_status bit)

DECLARE @dbconnect_sqlcmd varchar(1000)

SET @dbconnect_sqlcmd = ''

DECLARE dbbconnect_cursor CURSOR FAST_FORWARD FOR

SELECT 'select distinct '''+dbname+''', 1 from ['+dbname+'].sys.database_permissions a

inner join ['+dbname+'].sys.database_principals b on a.grantee_principal_id = b.principal_id

inner join ['+dbname+'].sys.server_principals c on b.sid = c.sid

where c.name = '''+@login_name+''''

from #alldb_users_access

OPEN dbbconnect_cursor

FETCH NEXT FROM dbbconnect_cursor INTO @dbconnect_sqlcmd

WHILE @@FETCH_STATUS = 0

BEGIN

INSERT INTO #dbconnect exec( @dbconnect_sqlcmd)

FETCH NEXT FROM dbbconnect_cursor INTO @dbconnect_sqlcmd

END

CLOSE dbbconnect_cursor

DEALLOCATE dbbconnect_cursor

insert into #dbconnect

select a.dbname, 0 from #alldb_users_access a left join #dbconnect b on a.dbname = b.dbname

where b.dbname is null

---------------------------------------------------------------------------------------

-- Grant all securable class to login

----------------------------------------------------------------------------------------

PRINT ''

PRINT '----------------------------------------------'

PRINT '--Grant all securable class to login '

PRINT '----------------------------------------------'

IF OBJECT_ID('tempdb..#securable_class') is not null

BEGIN

DROP TABLE #securable_class

END

IF OBJECT_ID('tempdb..#dblevel') is not null

BEGIN

DROP TABLE #dblevel

END

create table #dblevel (login_name varchar(256), dbname sysname, dbuser_name varchar(100), class_desc varchar(100), permission_name varchar(100), state_desc varchar(100))

DECLARE @dblevel_sqlcmd varchar(1000)

DECLARE dblevel_cursor CURSOR FAST_FORWARD FOR

SELECT 'select '''+@login_name+''' as login_name, '''+dbname+''' as dbname, b.name as dbuser_name, a.class_desc, a.permission_name, state_desc from ['+dbname+'].sys.database_permissions a inner join ['+dbname+'].sys.database_principals b

on a.grantee_principal_id = b.principal_id

where b.name in (''public'','''+name+''') and class_desc = ''DATABASE'''

FROM #alldb_users_access

union

SELECT 'select '''+@login_name+''' as login_name, ''master'' as dbname, b.name as dbuser_name, a.class_desc, a.permission_name, state_desc from sys.server_permissions a inner join sys.server_principals b

on a.grantee_principal_id = b.principal_id

where b.name = '''+@login_name+''''

UNION

on a.grantee_principal_id = b.principal_id and class_desc = ''SERVER''

where b.name = ''public'''

OPEN dblevel_cursor

FETCH NEXT FROM dblevel_cursor INTO @dblevel_sqlcmd

WHILE @@FETCH_STATUS = 0

BEGIN

INSERT INTO #dblevel (login_name, dbname, dbuser_name, class_desc, permission_name, state_desc) EXEC (@dblevel_sqlcmd)

FETCH NEXT FROM dblevel_cursor INTO @dblevel_sqlcmd

END

CLOSE dblevel_cursor

DEALLOCATE dblevel_cursor

SET NOCOUNT ON

DELETE FROM #dblevel WHERE permission_name IN ('SELECT','INSERT','UPDATE','DELETE','REFERENCES')

DELETE FROM #dblevel WHERE dbname IN (SELECT dbname FROM #dbrole WHERE sid = @login_sid AND dbrole = 'db_owner')

DECLARE @securable_sqlcmd varchar(150)

DECLARE securable_cursor CURSOR FAST_FORWARD FOR

SELECT distinct 'USE ['+dbname+']

GRANT '+permission_name+' TO ['+@login_name+']

' FROM #dblevel

OPEN securable_cursor

FETCH NEXT FROM securable_cursor INTO @securable_sqlcmd

WHILE @@FETCH_STATUS = 0

BEGIN

PRINT @securable_sqlcmd

FETCH NEXT FROM securable_cursor INTO @securable_sqlcmd

END

CLOSE securable_cursor

DEALLOCATE securable_cursor

If you input a bad login name to the script, it will produce an exception; below are the scenarios.

Scenario 1: If you enter either 'sa' or 'public', then you will see results similar to the below snapshot in the SSMS result pane (Fig. 1.1).

Fig 1.1

Scenario 2: If the login you provide doesn't exist on the SQL instance, then you will see results similar to the below snapshot in the SSMS result pane (Fig 1.2)

Fig 1.2

Now we can look into the real scenario about a valid login with permissions on server and database-level securables. By replacing 'YourLoginName' with a valid login, below is an example of how the outcome of the script will look. It contains the creation of the database user for the login and the permission setting for server and database securables. If a login is db_owner for any database or is part of sysadmin server role member, then the resulting script will only contain the execution of system stored procedure sp_addrolemember and sp_addsrvrolemember instead of printing out granting securables one by one.

Fig 1.3

Scenario 4: Input login is member of db_owner on AdventureWorksDW, not for the rest of the databases (Fig 1.4)

----------------------------------------------

--Create database user for login

----------------------------------------------

USE [master]

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = 'chsu')

BEGIN

CREATE USER [chsu] FOR LOGIN [chsu] WITH DEFAULT_SCHEMA=[dbo]

END

USE [AdventureWorks]

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = 'chsu')

BEGIN

CREATE USER [chsu] FOR LOGIN [chsu] WITH DEFAULT_SCHEMA=[dbo]

END

USE [Northwind]

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = 'chsu')

BEGIN

CREATE USER [chsu] FOR LOGIN [chsu] WITH DEFAULT_SCHEMA=[dbo]

END

USE [AdventureWorksDW]

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = 'chsu')

BEGIN

CREATE USER [chsu] FOR LOGIN [chsu] WITH DEFAULT_SCHEMA=[dbo]

END

----------------------------------------------

--Login is db_owner of below databases

----------------------------------------------

USE [AdventureWorksDW]

EXEC sp_addrolemember 'db_owner','user_dbo_bond_bg'

----------------------------------------------

--Grant all securable class to login

----------------------------------------------

USE [Northwind]

GRANT ALTER ANY APPLICATION ROLE TO [chsu]

USE [Northwind]

GRANT ALTER ANY ROUTE TO [chsu]

USE [Northwind]

GRANT CONNECT TO [chsu]

USE [Northwind]

GRANT CREATE ROUTE TO [chsu]

USE [Northwind]

GRANT SHOWPLAN TO [chsu]

USE [master]

GRANT ALTER ANY LINKED SERVER TO [chsu]

USE [master]

GRANT ALTER SETTINGS TO [chsu]

USE [master]

GRANT CONNECT SQL TO [chsu]

USE [master]

GRANT CONNECT TO [chsu]

USE [master]

GRANT EXTERNAL ACCESS ASSEMBLY TO [chsu]

USE [master]

GRANT UNSAFE ASSEMBLY TO [chsu]

USE [master]

GRANT VIEW ANY DATABASE TO [chsu]

USE [AdventureWorks]

GRANT CONNECT TO [chsu]

USE [AdventureWorks]

GRANT SHOWPLAN TO [chsu]

Fig 1.4

Conclusion

We have covered login regeneration in the first article with login creation, server-level role and database-level role assignment. In this artcile, we have summarized how to produce script for login on server-level and database-level securables.

In my final article of the series, I'll tackle the login generation for the finest scope securable – object-level permission for the login.

See all articles by Claire Hsu

Re-generating SQL Server Logins, Part 2

What is a securable?

Server-level permission

Permission on database-level securable

Grant, revoke and deny

Generate script for server and database securable class

Conclusion

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