Masalahnya di sini adalah bahwa sementara Sertifikat menautkan prosedur tersimpan di DatabaseA dengan Pengguna di DatabaseB yang memiliki INSERTizin pada dua tabel, Pemicu pada tabel yang dimasukkan langsung dari prosedur tersimpan adalah modul lain dalam rantai, dan izin diperoleh dari Sertifikat tidak lulus bersama ke modul lain dalam satu rantai. Artinya, Sertifikat memungkinkan Prosedur Tersimpan untuk dimasukkan ke dalam tabel melalui Pengguna, dan bahkan menjalankan Pemicu. Tetapi, tidak ada izin yang diberikan kepada Pemicu untuk melakukan sesuatu yang berhubungan dengan objek (melakukan sesuatu seperti itu SELECT 1;akan berhasil).
Dalam hal ini, izin harus diberikan kepada Pemicu, melalui Sertifikat yang sama, sehingga dapat mengambil tindakan apa pun yang diperlukan. Ini dapat dicapai, paling tidak, dengan menandatangani Trigger. Dan Anda melakukannya dengan mengeksekusi ADD COUNTER SIGNATURE TO [TriggerSchema].[TriggerName] BY CERTIFICATE ...;. Setelah itu, itu hanya akan berfungsi, bahkan tanpa INSERTizin langsung untuk Pengguna berbasis Sertifikat di atas meja yang dimasukkan oleh Pemicu.
Contoh kode di bawah ini mereproduksi masalah, memperbaiki masalah dengan menambahkan tanda tangan konter, tetapi tidak memberikan INSERTizin ke tabel terpicu-diisi.
MEMBERSIHKAN
USE [master];
GO
IF EXISTS (SELECT 1 FROM [sys].[databases] WHERE [name] = N'DatabaseA')
BEGIN
PRINT 'Dropping [DatabaseA] DB...';
ALTER DATABASE [DatabaseA] SET OFFLINE WITH ROLLBACK IMMEDIATE;
ALTER DATABASE [DatabaseA] SET ONLINE;
DROP DATABASE [DatabaseA];
END;
IF EXISTS (SELECT 1 FROM [sys].[databases] WHERE [name] = N'DatabaseB')
BEGIN
PRINT 'Dropping [DatabaseB] DB...';
ALTER DATABASE [DatabaseB] SET OFFLINE WITH ROLLBACK IMMEDIATE;
ALTER DATABASE [DatabaseB] SET ONLINE;
DROP DATABASE [DatabaseB];
END;
IF (SUSER_ID(N'JohnnyLunchbucket') IS NOT NULL)
BEGIN
PRINT 'Dropping [JohnnyLunchbucket] Login...';
DROP LOGIN [JohnnyLunchbucket];
END;
IF (OBJECT_ID(N'tempdb..#CertInfo') IS NOT NULL)
BEGIN
PRINT 'Dropping [#CertInfo] Temp Table...';
DROP TABLE #CertInfo;
END;
MEMPERSIAPKAN
USE [master];
EXECUTE AS LOGIN = N'sa';
PRINT 'Creating databases...';
CREATE DATABASE [DatabaseA] COLLATE Latin1_General_100_CI_AS_SC;
CREATE DATABASE [DatabaseB] COLLATE Latin1_General_100_CI_AS_SC;
REVERT;
GO
-- Default for both options should be OFF, but just to be sure:
ALTER DATABASE [DatabaseA] SET DB_CHAINING OFF;
ALTER DATABASE [DatabaseA] SET TRUSTWORTHY OFF;
ALTER DATABASE [DatabaseB] SET DB_CHAINING OFF;
ALTER DATABASE [DatabaseB] SET TRUSTWORTHY OFF;
GO
CREATE LOGIN [JohnnyLunchbucket] WITH PASSWORD = 'OhSoSecure;)';
USE [DatabaseA];
CREATE USER [JohnnyLunchbucket] FOR LOGIN [JohnnyLunchbucket];
GO
--DROP PROCEDURE dbo.InsertIntoTableWithoutTrigger;
CREATE PROCEDURE dbo.InsertIntoTableWithoutTrigger
(
@SomeValue NVARCHAR(50)
)
AS
SET NOCOUNT ON;
INSERT INTO [DatabaseB].[dbo].[TableWithoutTrigger] (SomeValue)
VALUES (@SomeValue);
GO
GRANT EXECUTE ON dbo.InsertIntoTableWithoutTrigger TO [JohnnyLunchbucket];
GO
CREATE PROCEDURE dbo.InsertIntoTableWithTrigger
AS
SET NOCOUNT ON;
INSERT INTO [DatabaseB].[dbo].[TableWithTrigger] (SomeOtherValue)
VALUES (NEWID());
GO
GRANT EXECUTE ON dbo.InsertIntoTableWithTrigger TO [JohnnyLunchbucket];
CREATE CERTIFICATE [PermissionsCert]
AUTHORIZATION [dbo]
ENCRYPTION BY PASSWORD = 'WeakPassword'
WITH SUBJECT = 'Used to test granting permissions to code',
EXPIRY_DATE = '2099-12-31';
ADD SIGNATURE TO [dbo].[InsertIntoTableWithoutTrigger]
BY CERTIFICATE [PermissionsCert]
WITH PASSWORD = 'WeakPassword';
ADD SIGNATURE TO [dbo].[InsertIntoTableWithTrigger]
BY CERTIFICATE [PermissionsCert]
WITH PASSWORD = 'WeakPassword';
-- Save Certificate info in temporary table so we can recreate in DatabaseB
SELECT CERTENCODED(CERT_ID(N'PermissionsCert')) AS [PublicKey],
CERTPRIVATEKEY(CERT_ID(N'PermissionsCert'), 'OtherPassword', 'WeakPassword')
AS [PrivateKey]
INTO #CertInfo;
GO
USE [DatabaseB];
DECLARE @SQL NVARCHAR(MAX);
SELECT @SQL = N'CREATE CERTIFICATE [PermissionsCert] AUTHORIZATION [dbo] FROM BINARY = '
+ CONVERT(NVARCHAR(MAX), [PublicKey], 1)
+ N' WITH PRIVATE KEY (BINARY = '
+ CONVERT(NVARCHAR(MAX), [PrivateKey], 1)
+ N', DECRYPTION BY PASSWORD = N''OtherPassword'''
+ N', ENCRYPTION BY PASSWORD = ''WeakPassword'');'
FROM #CertInfo;
PRINT @SQL;
EXEC (@SQL);
CREATE USER [PermissionsUser] FROM CERTIFICATE [PermissionsCert];
--DROP TABLE dbo.[TableWithoutTrigger];
CREATE TABLE dbo.[TableWithoutTrigger]
(
[TableWithoutTriggerID] INT NOT NULL IDENTITY(1, 1)
CONSTRAINT [PK_TableWithoutTrigger] PRIMARY KEY,
[SomeValue] NVARCHAR(50)
);
GRANT INSERT ON [dbo].[TableWithoutTrigger] TO [PermissionsUser];
CREATE TABLE dbo.[TableWithTrigger]
(
[TableWithTriggerID] INT NOT NULL IDENTITY(1, 1)
CONSTRAINT [PK_TableWithTrigger] PRIMARY KEY,
[SomeOtherValue] NVARCHAR(50)
);
GRANT INSERT ON [dbo].[TableWithTrigger] TO [PermissionsUser];
CREATE TABLE dbo.[TablePopulatedByTrigger]
(
[TablePopulatedByTriggerID] INT NOT NULL IDENTITY(1, 1)
CONSTRAINT [PK_TablePopulatedByTrigger] PRIMARY KEY,
[DuplicatedValue] NVARCHAR(50)
);
GO
CREATE TRIGGER dbo.CopySomeOtherValue
ON dbo.[TableWithTrigger]
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON;
INSERT INTO dbo.[TablePopulatedByTrigger] ([DuplicatedValue])
SELECT ins.[SomeOtherValue]
FROM inserted ins;
END;
GO
UJI 1: Pemicu gagal
USE [DatabaseA];
EXECUTE AS LOGIN = 'JohnnyLunchbucket';
SELECT SESSION_USER AS [User], ORIGINAL_LOGIN() AS [OriginalLogin];
GO
SELECT * FROM [DatabaseB].[dbo].[TableWithoutTrigger];
SELECT * FROM [DatabaseB].[dbo].[TableWithTrigger];
SELECT * FROM [DatabaseB].[dbo].[TablePopulatedByTrigger];
INSERT INTO [DatabaseB].[dbo].[TableWithoutTrigger] ([SomeValue]) VALUES (N'test 0');
USE [DatabaseB];
/* -- All 5 statements above get the following error:
Msg 916, Level 14, State 1, Line xxxxxx
The server principal "JohnnyLunchbucket" is not able to access the database
"DatabaseB" under the current security context.
*/
EXEC [dbo].[InsertIntoTableWithoutTrigger] @SomeValue = N'test A'; -- SUCCESS!!!
EXEC [dbo].[InsertIntoTableWithTrigger]; -- ERROR:
/*
Msg 916, Level 14, State 1, Procedure CopySomeOtherValue, Line xxxxxx
The server principal "JohnnyLunchbucket" is not able to access the database
"DatabaseB" under the current security context.
*/
REVERT;
SELECT SESSION_USER AS [User], ORIGINAL_LOGIN() AS [OriginalLogin];
-- Check to make sure that dbo.InsertIntoTableWithoutTrigger really did work:
SELECT * FROM [DatabaseB].[dbo].[TableWithoutTrigger];
-- 1 test A
UJI 2: Pemicu berhasil
Harap dicatat bahwa satu - satunya perubahan yang dilakukan adalah ADD COUNTER SIGNATURE; tidak ada GRANT INSERT ON dbo.TablePopulatedByTrigger TO [PermissionsUser];.
USE [DatabaseB];
ADD COUNTER SIGNATURE
TO dbo.[CopySomeOtherValue]
BY CERTIFICATE [PermissionsCert]
WITH PASSWORD = 'WeakPassword';
GO
USE [DatabaseA];
EXECUTE AS LOGIN = 'JohnnyLunchbucket';
SELECT SESSION_USER AS [User], ORIGINAL_LOGIN() AS [OriginalLogin];
GO
INSERT INTO [DatabaseB].[dbo].[TableWithTrigger] ([SomeOtherValue]) VALUES (N'Test B');
INSERT INTO [DatabaseB].[dbo].[TablePopulatedByTrigger]([DuplicatedValue]) VALUES ('Test B')
/*
Msg 916, Level 14, State 1, Line xxxxxx
The server principal "JohnnyLunchbucket" is not able to access the database
"DatabaseB" under the current security context.
*/
EXEC [dbo].[InsertIntoTableWithTrigger]; -- SUCCESS!!!
REVERT;
SELECT SESSION_USER AS [User], ORIGINAL_LOGIN() AS [OriginalLogin];
SELECT * FROM [DatabaseB].[dbo].[TableWithTrigger];
SELECT * FROM [DatabaseB].[dbo].[TablePopulatedByTrigger];
-- 2 968DB092-C3DE-4E4B-92B9-E21CA551A5FA
-- 1 968DB092-C3DE-4E4B-92B9-E21CA551A5FA