Is there a way to restrict the user to view all the schemas in a database?
Scenario:
I have a database with multiple schemas. I need to give access to a user for a particular schema and it's tabled.
Even though I try revoking all the access to that particular user and PUBLIC group, still he can view all the schemas and its tables. (Only the data he can't view.
I tried below commands:
REVOKE ALL ON SCHEMA devops_test FROM testuser;
REVOKE ALL ON SCHEMA devops_test FROM PUBLIC;
REVOKE ALL on all tables IN SCHEMA devops_test FROM testuser;
Once connected to database, users can read a list of all databases, schema's, tables, and even table columns in the cluster from the system tables, even if they are prevented from reading the data within those tables through the use of REVOKE ALL FROM. Try this:
REVOKE USAGE ON SCHEMA information_schema FROM PUBLIC;
REVOKE USAGE ON SCHEMA pg_catalog FROM PUBLIC;
REVOKE SELECT ON TABLE pg_catalog.pg_database FROM PUBLIC;
If I’ve made a bad assumption please comment and I’ll refocus my answer.
Related
I try add audit trigger for table in BD. I find example on GitHub. But I dont understand why author use this construction after create schema and table
CREATE SCHEMA audit;
REVOKE ALL ON SCHEMA audit FROM public;
And for table:
REVOKE ALL ON audit.logged_actions FROM public;
What the aim of using REVOKE ?
Revoke removes access permissions to an object.
it means only specific users that you will grant permission to them can access the audit scheme / logged_actions table.
"The key word PUBLIC refers to the implicitly defined group of all roles."
The REVOKE is pointless, because the default permissions on a new schema only allow the owner (the user that ran CREATE SCHEMA) to use it. See the documentation:
No privileges are granted to PUBLIC by default on tables, table columns, sequences, foreign data wrappers, foreign servers, large objects, schemas, tablespaces, or configuration parameters.
I can only assume that the REVOKE is a safety measure, in case the user who runs CREATE SCHEMA has changed the default privileges as follows:
ALTER DEFAULT PRIVILEGES GRANT ... ON SCHEMAS TO PUBLIC;
I am the admin of a PostgreSQL 11 DB on Azure.
Some of the users only have access to specific views.
The users were created by:
CREATE USER M1234 WITH PASSWORD '1234!';
GRANT USAGE ON SCHEMA public TO M1234;
GRANT SELECT ON table v_xxx TO M1234;
GRANT SELECT ON table v_yyy TO M1234;
For some reason the grant for select on one or all the existing views is removed every so often and the users of course cannot access.
I would really appreciate it if anyone has any insight as to why and how this could happen and if there is a more long term solution.
You grant SELECT on existing tables, but for future tables, you need additional permissions
-- Grant access to future tables ALTER DEFAULT PRIVILEGES IN SCHEMA a_given_schema GRANT SELECT ON TABLES TO read access;
I have a bit of a funny situation in Amazon Redshift where I have a user X who has grant select on all tables in schema public, but once a new table is created, this grant doesn't seem to apply to the new table. Is this normal behaviour? If yes, how does one deal with it such that the schema level grants are maintained. Thank you.
Executing the following command as super user (master):
alter default privileges
for user staging_user
in schema staging
grant select on tables
to reporting_user;
will allow reporting_user to select data from all future tables created by staging_user in schema staging.
In Redshift tables and views do not automatically inherit the permissions of their parent schema. Your newly created tables are only accessible to the user who created them, and the superuser.
In a recent patch to Redshift a new feature to grant default privileges was implemented that addresses this issue.
Alter Default Privileges
The following code snippet will grant select privileges only for all future tables in the sales schema to the sales_admin group. If you want this to apply to existing tables in a schema you will need to combine it with a second grant statement.
alter default privileges in schema sales grant select on tables to group sales_admin;
This is a normal behavior. Only the object owner/superuser have permission to use the object by default.
http://docs.aws.amazon.com/redshift/latest/dg/r_Privileges.html
You can add grant command to your create table statement and grant needed privileges for the user.
When we first spotted new tables not appearing in our reporting tool, I discovered a quick workaround is to re-execute the following SQL statement for the groups/users impacted:
ALTER DEFAULT PRIVILEGES IN SCHEMA <SCHEMANAME> GRANT SELECT ON TABLES TO GROUP <USER/GROUPNAME>;
Is there a way I can revoke permissions from a user to the catalog objects (i.e. information_schema) and PostgreSQL tables (i.e. pg_catalog)? I've tried several things and scoured the net. I'm not having any luck. The only thing I read that is partially helpful is I may not want to remove "public" from the system tables in case user defined functions rely on an object in one of those schemas. The commands below are a small snap shot of what I have not gotten to work with the exception of a single table.
REVOKE ALL PRIVILEGES ON SCHEMA pg_catalog FROM PUBLIC; -- didn't work
REVOKE ALL PRIVILEGES ON SCHEMA pg_catalog FROM public; -- didn't work
REVOKE ALL PRIVILEGES ON SCHEMA pg_catalog FROM user1; -- didn't work
REVOKE SELECT ON pg_catalog.pg_roles FROM user1; -- worked
REVOKE SELECT ON pg_catalog.pg_database FROM user1; -- didn't work
REVOKE ALL PRIVILEGES ON SCHEMA pg_catalog FROM g_users; -- didn't work
REVOKE SELECT ON pg_catalog.pg_database FROM g_users; -- didn't work
Any ideas? Or is this just not possible? Thanks...
Leslie
let me help you about this:
1st: because the pg_catalog is owned by the superuser postgres, so make sure you login to the server with this role:
pg_catalog schema permission
2nd: make sure you connect to the right database that needs to GRANT/REVOKE permissions on. GRANT/REVOKE only affect to the current database that you connected to. That means after you login with superuser account, issue: \c [the db] to connect to that database, the shell will change to: [the db]=>
3rd: tables in pg_catalog defaults granted SELECT to PUBLIC: tables in pg_catalog. So, you have to run REVOKE SELECT FROM PUBLIC and then GRANT SELECT to appropriate users:
REVOKE SELECT ON ALL TABLES IN SCHEMA pg_catalog FROM PUBLIC;
GRANT SELECT ON TABLE [table] TO [user];
For list tables in a database: pg_class and pg_namespace.
And that's all :)
What you are trying to accomplish is denied in PostgreSQL by design.
If a user could not access pg_catalog schema (as you try to do with REVOKE commands), he/she would not be able to run even simplest SELECT query - planner would have no access to table definitions.
Your goal might be achieved by REVOKE'ing access to all schemas - hence locking user only in his private schema (with CREATE SCHEMA AUTHORIZATION username).
If any rights are already GRANT'ed to public, you cannot block them selectively for one user - you can only REVOKE ... FROM public.
Relevant documentation:
Creating a Schema
Schemas and Privileges
I have multiple databases, each one with multiple schemas. Something like this:
db1
schema1
schema2
db2
schema1
schema2
db3
schema1
schema2
I need to grant access to someuser *only to* db1.schema2.
In the pg_hba.conf I can restrict which user connects to wich database. And in the schema1 I can revoke usage and create privileges.
At this moment someuser can connect only to db1 and only can create tables in schema2 not in schema1.
However, the user can view the structure of the tables in schema1.
Is it posible to avoid someuser to view the structure of the tables in schema1?
First, schemas aren't used in the hba.conf flie. What you're looking for are simply grants and revokes. You're wanting to revoke "usage" of the schema from the role or perhaps the public role. According to the documentation, there are still other ways (ie, the system tables) to query this information, but it'll hide it from the front end. In short, there's no way to absolutely deny all ways of seeing the table description, and apparently the designers don't see a need to implement such a feature.
See discussion here
Revoking usage of the schema:
revoke usage on schema myschema from myrole