[MDEV-18440] Information_schema.check_constraints possible data leak Created: 2019-01-31  Updated: 2019-12-13  Resolved: 2019-12-13

Status: Closed
Project: MariaDB Server
Component/s: Information Schema
Affects Version/s: 10.2, 10.3
Fix Version/s: 10.2.31, 10.3.22, 10.4.12

Type: Bug Priority: Major
Reporter: Vicențiu Ciorbaru Assignee: Anel Husakovic
Resolution: Fixed Votes: 0
Labels: None


 Description   

information_schema.check_constraints can leak unwanted information via check constraints definitions. For example, a user can infer column names from a table:

create user foo;
 
 
 
create database db;
 
use db;
 
create table t1 (a int, b int, CONSTRAINT CHECK (b > 0));
 
insert into t1 values (1, 2), (2, 3);
 
grant select (a) on t1 to foo;
 
 
 
show grants for foo;
 
 
 
select * from information_schema.check_constraints;
 
 
 
CONNECT(con1,localhost, foo,, db);
 
select a from t1;
 
select * from information_schema.check_constraints;
 
 
 
--CONNECTION DEFAULT;
 
 
 
drop database db;

This will print, when logged in as user foo:

select * from information_schema.check_constraints;
 
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_NAME	CHECK_CLAUSE
 
def	db	t1	CONSTRAINT_1	`b` > 0

So now, user foo knows table t1 has a `b` column.

 Comments   
Comment by Anel Husakovic [ 2019-12-13 ]

Pushed with 8129ff14407826 on 10.2 , 193b5ed50bc203a on 10.3

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