ALTER MASKING POLICY

Description

Modifies a masking policy.

Precautions

Only users with the poladmin or sysadmin permission, or the initial user can perform this operation.
The masking policy takes effect only after the security policy is enabled, that is, enable_security_policy is set to on.

Syntax

Modify the policy description.

      
           ALTER MASKING POLICY policy_name COMMENTS policy_comments;

Modify the masking method.

      
           ALTER MASKING POLICY policy_name {ADD | REMOVE | MODIFY} masking_actions[, ...];

The syntax of masking_actions

        
             masking_function ON LABEL(label_name[, ...])

The syntax of masking_function

        
             {maskall | randommasking | creditcardmasking | basicemailmasking | fullemailmasking | shufflemasking | alldigitsmasking | regepmasking}

Modify the scenarios where the masking policies take effect.

      
           ALTER MASKING POLICY policy_name MODIFY (filter_group_clause);

The syntax of filter_group_clause

        
                 FILTER ON { ( FILTER_TYPE ( filter_value [, ... ] ) ) [, ... ] }

Remove the filters of the masking policies.

      
           ALTER MASKING POLICY policy_name DROP FILTER;

Enable or disable the masking policies.

      
           ALTER MASKING POLICY policy_name {ENABLE | DISABLE};

Parameters

policy_name
Specifies the masking policy name, which must be unique.

Value range: a string. It must comply with the naming convention.
policy_comments
Adds or modifies description of masking policies.
masking_function
Specifies eight preset masking methods or user-defined functions. Schema is supported.

maskall is not a preset function and cannot be displayed by running \df.

The masking methods during presetting are as follows:
```
{ maskall | randommasking | creditcardmasking | basicemailmasking | fullemailmasking | shufflemasking | alldigitsmasking | regexpmasking }
```
label_name
Specifies the resource label name.

FILTER_TYPE
Specifies the types of information to be filtered by the policies: IP, ROLES, and APP.
filter_value
Indicates the detailed information to be filtered, such as the IP address, app name, and username.

ENABLE|DISABLE
Enables or disables the masking policy. If ENABLE|DISABLE is not specified, ENABLE is used by default.

Examples

Modify the policy description.

-- Create table tb_for_masking.
gaussdb=# CREATE TABLE tb_for_masking(idx int, col1 text, col2 text, col3 text, col4 text, col5 text, col6 text, col7 text,col8 text);

-- Insert data into the tb_for_masking table.
gaussdb=# INSERT INTO tb_for_masking VALUES(1, '9876543210', 'usr321usr', 'abc@huawei.com', 'abc@huawei.com', '1234-4567-7890-0123', 'abcdef 123456 ui 323 jsfd321 j3k2l3', '4880-9898-4545-2525', 'this is a llt case'); 

-- View data.
gaussdb=# SELECT * FROM tb_for_masking;
 idx |    col1    |   col2    |      col3      |      col4      |        col5         |                col6           
      |        col7         |        col8        
-----+------------+-----------+----------------+----------------+---------------------+-------------------------------
------+---------------------+--------------------
   1 | 9876543210 | usr321usr | abc@huawei.com | abc@huawei.com | 1234-4567-7890-0123 | abcdef 123456 ui 323 jsfd321 j
3k2l3 | 4880-9898-4545-2525 | this is a llt case
(1 row)

-- Create a resource label for sensitive column col1.
gaussdb=# CREATE RESOURCE LABEL mask_lb1 ADD COLUMN(tb_for_masking.col1);

-- Create a data masking policy named maskpol1.
gaussdb=# CREATE MASKING POLICY maskpol1 maskall ON LABEL(mask_lb1);

-- Add description for masking policy maskpol1.
gaussdb=# ALTER MASKING POLICY maskpol1 COMMENTS 'masking policy for tb_for_masking.col1';

-- View the description of data masking policy maskpol1.
gaussdb=# SELECT * FROM GS_MASKING_POLICY;                
 polname  |              polcomments               |         modifydate         | polenabled 
----------+----------------------------------------+----------------------------+------------
 maskpol1 | masking policy for tb_for_masking.col1 | 2023-11-07 16:38:31.607374 | t
(1 row)

Modify a masking policy.

-- Create a resource label for sensitive column col2.
gaussdb=# CREATE RESOURCE LABEL mask_lb2 ADD COLUMN(tb_for_masking.col2);

-- Add the randommasking masking mode to the masking policy maskpol1.
gaussdb=# ALTER MASKING POLICY maskpol1 ADD randommasking ON LABEL(mask_lb2);

-- Access the tb_for_masking table. The masking policy is triggered for the col2 column.
gaussdb=# SELECT col2 FROM tb_for_masking;
    col2   
------------
 27e8da66cc
(1 row)

-- Remove the randommasking masking mode from the masking policy maskpol1.
gaussdb=# ALTER MASKING POLICY maskpol1 REMOVE randommasking ON LABEL(mask_lb2);

-- Access the tb_for_masking table. The data in the col2 column is not masked, indicating that the masking mode randommasking is invalid.
gaussdb=# SELECT col2 FROM tb_for_masking;
   col2    
-----------
 usr321usr
(1 row)

-- Change the masking mode of the masking policy maskpol1 to randommasking.
gaussdb=# ALTER MASKING POLICY maskpol1 MODIFY randommasking ON LABEL(mask_lb1);

-- Access the tb_for_masking table. The masking policy is triggered for the col1 column.
gaussdb=# SELECT col1 FROM tb_for_masking;
    col1    
------------
 5a03debac1
(1 row)

Modify the scenarios where the masking policies take effect.

-- Create users dev_mask and bob_mask.
gaussdb=# CREATE USER dev_mask PASSWORD '********';
gaussdb=# CREATE USER bob_mask PASSWORD '*********';

-- Create a resource label for sensitive column col8.
gaussdb=# CREATE RESOURCE LABEL mask_lb8 ADD COLUMN(tb_for_masking.col8); 

-- Create a data masking policy named maskpol8.
gaussdb=# CREATE MASKING POLICY maskpol8 randommasking ON LABEL(mask_lb8) FILTER ON ROLES(dev_mask, bob_mask), APP(gsql), IP('172.31.17.160', '127.0.0.0/24');

-- Modify the filtering information by specifying ROLES of data masking policy maskpol8.
gaussdb=# ALTER MASKING POLICY maskpol1 MODIFY (FILTER ON ROLES(dev_mask));

-- Check tb_for_masking as the dev_mask user.
gaussdb=# GRANT ALL PRIVILEGES TO dev_mask;

-- Access the tb_for_masking table. The masking policy is triggered for the col8 column.
gaussdb=# SELECT col8 FROM tb_for_masking;
        col8        
--------------------
 f134e06ef528013b46
(1 row)

Remove the filters of the masking policies for the policies to take effect.
```
gaussdb=# ALTER MASKING POLICY maskpol1 DROP FILTER;
```

Disable a masking policy.

-- Disable masking policy maskpol1.
gaussdb=# ALTER MASKING POLICY maskpol1 DISABLE;

-- Check the status of data masking policy maskpol1. If the value of polenabled is f, the data masking policy is disabled successfully.
gaussdb=# SELECT * FROM GS_MASKING_POLICY;
 polname  | polcomments |         modifydate         | polenabled 
----------+-------------+----------------------------+------------
 maskpol1 |             | 2023-11-07 17:22:54.594111 | f

Delete data.

-- Delete a masking policy.
gaussdb=# DROP MASKING POLICY maskpol1, maskpol8;

-- Delete a resource label.
gaussdb=# DROP RESOURCE LABEL mask_lb1, mask_lb2, mask_lb8;

-- Delete the tb_for_masking table.
gaussdb=# DROP TABLE tb_for_masking;

-- Delete the dev_mask and bob_mask users.
gaussdb=# DROP USER dev_mask, bob_mask;