Is there a way to allow a user to bypass RLS for all tables is Postgres?
According to the documentation, it is possible for a user to be assigned the BYPASSRLS attribute by another superuser. With this, a user can bypass RLS for all tables in Postgres.
And of course, superusers can bypass RLS be default.
Related
I have multiple databases and each of them have multiple schemas.
I have a set of apps that connect to these databases. Each app has it own user and, depending on their function, the apps can:
read / write all schemas and tables of a specific db, set functions/notifications
read only all schemas and tables of a specific db
The schemas and tables can be created at any time, so the permissions need to be set with ALTER DEFAULT.
My understanding is that the ALTER DEFAULT has to be done by the user that will create the future tables. Is that correct?
Since I can have scenarios where User 1 can RO db A, but RW db B, while User 2 can only RO db B, etc.. using roles doesn't seem to be of any help here.
So I'm a bit confused how to set that up.
Then comes the next complication:
I can assign permissions as either SELECT (RO), or SELECT, INSERT, UPDATE, DELETE (RW), but:
what about sequences? I don't want a RW user to be able to alter the sequences, but they need to be able to use them
then how does it work with functions? the RW users need to be able to set/update their own functions
Any example of this setup would be greatly appreciated because going through the doc didn't help me much and most of the questions / answers on SO seems to be very similar yet never exactly the same, so it's quite confusing :)
Edit, following 'a_horse_with_no_name''s suggestion in the comments, I did this:
here is my init.sql:
CREATE DATABASE accounts;
CREATE DATABASE analysis;
CREATE DATABASE exchange;
GRANT CONNECT ON DATABASE exchange TO capture, analyzer, sunny, viewer;
GRANT CONNECT ON DATABASE analysis TO analyzer, sunny, viewer;
GRANT CONNECT ON DATABASE accounts TO sunny;
then I log in as admin to db exchange and do:
GRANT pg_write_all_data TO capture;
GRANT pg_read_all_data TO analyzer, sunny, viewer;
and I create a table called instruments there
then I log in as capture to to db exchange and do an insert, and I get:
42501: permission denied for table instruments
so using the capture user on the exchange db, I should have the pg_write_all_data property; why do I get the error?
It looks like I have to grant usage of instruments to capture.. which defeats the purpose of the pg_write_all_data. If I do the grant, then it works. So it looks like adding the role doesn't work.
Since your users shall have different permissions in different databases, define read-only and read-write roles for each database.
For example, db1_ro has read-only permissions in db1, and db2_rw has read-write permissions in db2. Then you can grant them both to a user, and the user will have different permissions in different databases.
Using a sequence typically means to call nextval(). So you should give that user the USAGE privilege. To use setval(), the user would need UPDATE. Nobody except the owner can ALTER an object anyway.
Functions cannot be set or updated, only executed, for which there is the EXECUTE privilege, which is granted to PUBLIC by default.
I have to log all such queries to my database on Amazon RDS
The best way, of course, create a trigger on pg_catalog.pg_authid, but I have no privileges to operate system catalog.
Any advice?
The best you can do is to set log_statement = 'ddl'. That will log other DDL statements as well.
I want to give permissions to a user on all the tables existing in a database. Is there any way to grant a user on multiple tables?
It is not possible to grant permissions to multiple objects in a single statement, you need to grant per object.
I installed PostgreSQL 9 database (migration from Oracle10g) and I am realy confused by user/role management. When I create new user using SQL command like CREATE USER or CREATE ROLE, or by Navicat tool, created user can see all databases! He realy can connect them! Although he can't select any data from table, he can see table objects and sequences and so on. I was trying revoke connect privilegia but no effect. I was expected the new user has no privilegia and cant see anything. I really don't know why he can.
From http://www.postgresql.org/docs/9.2/static/sql-grant.html#SQL-GRANT-DESCRIPTION-OBJECTS (emphasis mine):
PostgreSQL grants default privileges on some types of objects to PUBLIC. No privileges are granted to PUBLIC by default on tables, columns, schemas or tablespaces. For other types, the default privileges granted to PUBLIC are as follows: CONNECT and CREATE TEMP TABLE for databases; EXECUTE privilege for functions; and USAGE privilege for languages. The object owner can, of course, REVOKE both default and expressly granted privileges. (For maximum security, issue the REVOKE in the same transaction that creates the object; then there is no window in which another user can use the object.) Also, these initial default privilege settings can be changed using the ALTER DEFAULT PRIVILEGES command.
In order to remove all privileges (including CONNECT) for all unspecified users on a database, use:
REVOKE ALL PRIVILEGES ON DATABASE <database> FROM public;
See also:
PostgreSQL: View database connect permissions
http://wiki.postgresql.org/wiki/Shared_Database_Hosting
You probably also need to modify the pg_hba.conf file. By default, a local installation doesn't do authorization checks.
I want to create a postgres user that can access only one database on the postgres server at all.
Currently my flow is:
create database database1;
create user user1 with password 'pass';
grant all privileges on database database1 to user1;
but user1 can still see a list of dbs, users, tables etc. Is there a way to prevent that user from seeing that info? The user needs to be able to write to and read from that db.
Thanks a lot.
Each user can see other databases and roles listed, but should not be able to see tables in other databases, ever.
If you revoke CONNECT privilege on all databases except the allotted one, the user will not be able to access the contents of other databases.
Roles and database names are global, and not readily blockable. You can try Frank Heikens suggestion of selective revocations on the system tables, but you take risks to do that. PostgreSQL developers on the usenet mailing lists have discouraged tampering with access to the system catalogs.
Psql, among other tools, assumes they will be available and functions poorly without them.
Why is knowing the names of other databases and roles so bad?
REVOKE the SELECT permissions on the information_schema and some sections in the system catalog.
By default any objects you create are created in the public schema. Also, any users that you create have CREATE and USAGE privileges on the public schema. You should revoke CREATE and USAGE to the public schema for this user, or you should change the default access level. You'll also need to move the database to which this user has access into the user's schema, or a schema accessible to the user. See DDL Schemas in the Postgres manual.