SQL Server：未在另一个谓词函数中强制执行的表上的行级安全性

问题描述

请考虑以下内容：有两个表，表A和表B。在表A上实现RLS。

然后，在表B上通过内部联接将表B链接到表A来实现RLS。 猜猜在表B的谓词函数中什么会忽略表A的RLS。

1. 似乎，您需要在表B的谓词功能中重新应用表A的RLS。这是设计使然吗？

2. 在谓词函数中将表B链接到表A时，是否可以设置一些标志或“ with”子句以强制执行现有的RLS？

3. 我做错什么了吗？

用于创建和填充表的SQL脚本。

CREATE TABLE [dbo].[Securities]
(
    [SecurityId] [int] NOT NULL,[Security] [varchar](50) NOT NULL,[IssueCurrency] [varchar](3) NOT NULL,CONSTRAINT [PK_Securities] 
        PRIMARY KEY CLUSTERED ([SecurityId] ASC)
                    WITH (PAD_INDEX = OFF,STATISTICS_NORECOMPUTE = OFF,IGNORE_DUP_KEY = OFF,ALLOW_ROW_LOCKS = ON,ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[Prices]
(
    [SecurityId] [int] NOT NULL,[PriceDate] [date] NOT NULL,[Price] [numeric](18,4) NULL,CONSTRAINT [PK_Prices] 
        PRIMARY KEY CLUSTERED ([SecurityId] ASC,[PriceDate] ASC)
                    WITH (PAD_INDEX = OFF,ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[Prices] WITH CHECK 
    ADD CONSTRAINT [FK_Prices_Securities] 
        FOREIGN KEY([SecurityId]) REFERENCES [dbo].[Securities] ([SecurityId])
GO

ALTER TABLE [dbo].[Prices] CHECK CONSTRAINT [FK_Prices_Securities]
GO

INSERT INTO [dbo].[Securities] ([SecurityId],[Security],[IssueCurrency])
VALUES (1,'Project Power','CAD'),(2,'Fractured Ltd','AUD'),(5,'Eddy Security','USD'),(6,'Foxtrot','USD')
GO

INSERT INTO Prices ([SecurityId],[PriceDate],[Price])
VALUES (1,'2020-08-05',13.2500),(1,'2020-08-06',13.3500),'2020-08-07',13.0500),23.9500),24.1500),22.0500),105.1500),106.3500),105.0500),36.2500),36.3500),35.0500)

用于创建谓词功能和安全策略的SQL脚本。

/*
drop security policy if exists Policy_Securities
go 

drop function if exists dbo.rlsSecurities
go
*/

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE FUNCTION rlsSecurities (@IssueCurrency varchar(3))
RETURNS TABLE
WITH SCHEMABINDING
AS
RETURN 
    SELECT 1 AS UserAccess
        WHERE
            (SESSION_CONTEXT(N'UserGroup') = 'Internal')  or
            (
                @IssueCurrency = 'USD'      --non-internal group can only view securities where IssueCurrency='USD'         
            )
go

CREATE SECURITY POLICY Policy_Securities
ADD FILTER PREDICATE dbo.rlsSecurities(IssueCurrency) ON dbo.Securities
WITH(STATE = ON)
go

EXEC sys.sp_set_session_context @key=N'UserGroup',@value='XYZ'

SELECT SESSION_CONTEXT(N'UserGroup')

SELECT * FROM Securities

SELECT s.Security,p.*
FROM Securities s
INNER JOIN Prices p ON s.SecurityId = p.SecurityId  --RLS on table Prices is enforced thru inner join.

SELECT * FROM Prices  --Currently no RLS on tblComp.

--Now I want to implement RLS on Prices as well.
drop security policy if exists Policy_Prices
go 

drop function if exists dbo.rlsPrices
go

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
create FUNCTION rlsPrices (
    @SecurityId int)
RETURNS TABLE
WITH SCHEMABINDING
AS
RETURN 

    SELECT 1 as UserAccess
        where @SecurityId in (select SecurityId from dbo.Securities)  --This doesn't work even though RLS on table Securities already exists.
        
        --where   --This works but it requires reapplying RLS on table Securities.
        --  (SESSION_CONTEXT(N'UserGroup') = 'Internal')  or
        --  (
        --      @SecurityId In (select SecurityId from dbo.Securities where IssueCurrency = 'USD')      --non-internal group can only view securities where IssueCurrency='USD'         
        --  )
go

CREATE SECURITY POLICY Policy_Prices
ADD FILTER PREDICATE dbo.rlsPrices(SecurityId) ON dbo.Prices
WITH(STATE = ON)

go
exec sys.sp_set_session_context @key=N'UserGroup',@value='XYZ'
select SESSION_CONTEXT(N'UserGroup')
select * from Prices    --RLS not enforced

解决方法

您没有做错任何事情。

当在策略的范围/执行中执行tvf时，似乎RLS并未考虑谓词表值函数中引用的表上的任何现有策略。 在普通查询中执行时，tvf可以正常工作（执行tvf中的引用表{ie。Securities}的策略）：

--standalone...check the execution plan,predicate of Securities.PK_Securities index scan is the function/policy on currency='USD'
select p.* 
from Prices as p
cross apply dbo.rlsPrices(p.SecurityId)

如果您检查执行计划：

--filter policy on Prices
select * from Prices

您将仅看到对价格的聚集索引扫描，因为从价格到证券（SecurityId）存在FK，所以根本不检查证券表。 即使您删除FK，“价格与证券”之间的连接也会丢失任何有关证券的RLS谓词。

简而言之，筛选器策略不是嵌套/继承/级联的，无论是否设计使然。.尚不清楚。