Auth / HBA

Host-Based Authentication in Pigsty

PostgreSQL has various authentication methods. You can use all of them, while pigsty’s battery-included ACL system focuses on HBA, password, and SSL authentication.

Client Authentication

To connect to a PostgreSQL database, the user has to be authenticated (with a password by default).

You can provide the password in the connection string (not secure) or use the PGPASSWORD env or .pgpass file. Check psql docs and PostgreSQL connection string for more details.

psql 'host=<host> port=<port> dbname=<dbname> user=<username> password=<password>'
psql postgres://<username>:<password>@<host>:<port>/<dbname>
PGPASSWORD=<password>; psql -U <username> -h <host> -p <port> -d <dbname>

The default connection string for the meta database:

psql 'host=10.10.10.10 port=5432 dbname=meta user=dbuser_dba password=DBUser.DBA'
psql postgres://dbuser_dba:[email protected]:5432/meta
PGPASSWORD=DBUser.DBA; psql -U dbuser_dba -h 10.10.10.10 -p 5432 -d meta

To connect with the SSL certificate, you can use the PGSSLCERT and PGSSLKEY env or sslkey & sslcert parameters.

psql 'postgres://dbuser_dba:[email protected]:5432/meta?sslkey=/path/to/dbuser_dba.key&sslcert=/path/to/dbuser_dba.crt'

While the client certificate (CN = username) can be issued with local CA & cert.yml.

Define HBA

There are four parameters for HBA Rules in Pigsty:

pg_hba_rules: postgres ad-hoc hba rules
pg_default_hba_rules: postgres default hba rules
pgb_hba_rules: pgbouncer ad-hoc hba rules
pgb_default_hba_rules: pgbouncer default hba rules

Which are array of hba rule objects, and each hba rule is one of the following forms:

1. Raw Form

- title: allow intranet password access
  role: common
  rules:
    - host   all  all  10.0.0.0/8      md5
    - host   all  all  172.16.0.0/12   md5
    - host   all  all  192.168.0.0/16  md5

In the form, the title will be rendered as a comment line, followed by the rules as hba string one by one.

An HBA Rule is installed when the instance’s pg_role is the same as the role.

HBA Rule with role: common will be installed on all instances.

HBA Rule with role: offline will be installed on instances with pg_role = offline or pg_offline_query = true.

2. Alias Form

The alias form, which replace rules with addr, auth, user, and db fields.

- addr: 'intra'    # world|intra|infra|admin|local|localhost|cluster|<cidr>
  auth: 'pwd'      # trust|pwd|ssl|cert|deny|<official auth method>
  user: 'all'      # all|${dbsu}|${repl}|${admin}|${monitor}|<user>|<group>
  db: 'all'        # all|replication|....
  rules: []        # raw hba string precedence over above all
  title: allow intranet password access

addr: where
- world: all IP addresses
- intra: all intranet cidr: '10.0.0.0/8', '172.16.0.0/12', '192.168.0.0/16'
- infra: IP addresses of infra nodes
- admin: admin_ip address
- local: local unix socket
- localhost: local unix socket + tcp 127.0.0.1/32
- cluster: all IP addresses of pg cluster members
- <cidr>: any standard CIDR blocks or IP addresses
auth: how
- deny: reject access
- trust: trust authentication
- pwd: use md5 or scram-sha-256 password auth according to pg_pwd_enc
- sha/scram-sha-256: enforce scram-sha-256 password authentication
- md5: md5 password authentication
- ssl: enforce host ssl in addition to pwd auth
- ssl-md5: enforce host ssl in addition to md5 password auth
- ssl-sha: enforce host ssl in addition to scram-sha-256 password auth
- os/ident: use ident os user authentication
- peer: use peer authentication
- cert: use certificate-based client authentication
user: who
- all: all users
- ${dbsu}: database superuser specified by pg_dbsu
- ${repl}: replication user specified by pg_replication_username
- ${admin}: admin user specified by pg_admin_username
- ${monitor}: monitor user specified by pg_monitor_username
- ad hoc users & roles.
db: which
- all: all databases
- replication: replication database
- ad hoc database name

3. Where to Define

Typically, global HBA is defined in all.vars. If you want to modify the global default HBA rules, you can copy from the full.yml template to all.vars for modification.

pg_default_hba_rules: postgres global default HBA rules
pgb_default_hba_rules: pgbouncer global default HBA rules

Cluster-specific HBA rules are defined in the cluster-level configuration of the database:

pg_hba_rules: postgres HBA rules for the cluster
pgb_hba_rules: pgbouncer HBA rules for the cluster

Here are some examples of cluster HBA rule definitions.

pg-meta:
  hosts: { 10.10.10.10: { pg_seq: 1, pg_role: primary } }
  vars:
    pg_cluster: pg-meta
    pg_hba_rules:
      - { user: dbuser_view ,db: all    ,addr: infra        ,auth: pwd  ,title: 'allow grafana dashboard access cmdb from infra nodes'}
      - { user: all         ,db: all    ,addr: 100.0.0.0/8  ,auth: pwd  ,title: 'all user access all db from kubernetes cluster' }
      - { user: '${admin}'  ,db: world  ,addr: 0.0.0.0/0    ,auth: cert ,title: 'all admin world access with client cert'        }

Reload HBA

To reload postgres/pgbouncer hba rules:

bin/pgsql-hba <cls>                 # reload hba rules of cluster `<cls>`
bin/pgsql-hba <cls> ip1 ip2...      # reload hba rules of specific instances

The underlying command: are:

./pgsql.yml -l <cls> -e pg_reload=true -t pg_hba,pg_reload
./pgsql.yml -l <cls> -e pg_reload=true -t pgbouncer_hba,pgbouncer_reload

Default HBA

Pigsty has a default set of HBA rules, which is pretty secure for most cases.

The rules are self-explained in alias form.

pg_default_hba_rules:             # postgres default host-based authentication rules
  - {user: '${dbsu}'    ,db: all         ,addr: local     ,auth: ident ,title: 'dbsu access via local os user ident'  }
  - {user: '${dbsu}'    ,db: replication ,addr: local     ,auth: ident ,title: 'dbsu replication from local os ident' }
  - {user: '${repl}'    ,db: replication ,addr: localhost ,auth: pwd   ,title: 'replicator replication from localhost'}
  - {user: '${repl}'    ,db: replication ,addr: intra     ,auth: pwd   ,title: 'replicator replication from intranet' }
  - {user: '${repl}'    ,db: postgres    ,addr: intra     ,auth: pwd   ,title: 'replicator postgres db from intranet' }
  - {user: '${monitor}' ,db: all         ,addr: localhost ,auth: pwd   ,title: 'monitor from localhost with password' }
  - {user: '${monitor}' ,db: all         ,addr: infra     ,auth: pwd   ,title: 'monitor from infra host with password'}
  - {user: '${admin}'   ,db: all         ,addr: infra     ,auth: ssl   ,title: 'admin @ infra nodes with pwd & ssl'   }
  - {user: '${admin}'   ,db: all         ,addr: world     ,auth: ssl   ,title: 'admin @ everywhere with ssl & pwd'   }
  - {user: '+dbrole_readonly',db: all    ,addr: localhost ,auth: pwd   ,title: 'pgbouncer read/write via local socket'}
  - {user: '+dbrole_readonly',db: all    ,addr: intra     ,auth: pwd   ,title: 'read/write biz user via password'     }
  - {user: '+dbrole_offline' ,db: all    ,addr: intra     ,auth: pwd   ,title: 'allow etl offline tasks from intranet'}
pgb_default_hba_rules:            # pgbouncer default host-based authentication rules
  - {user: '${dbsu}'    ,db: pgbouncer   ,addr: local     ,auth: peer  ,title: 'dbsu local admin access with os ident'}
  - {user: 'all'        ,db: all         ,addr: localhost ,auth: pwd   ,title: 'allow all user local access with pwd' }
  - {user: '${monitor}' ,db: pgbouncer   ,addr: intra     ,auth: pwd   ,title: 'monitor access via intranet with pwd' }
  - {user: '${monitor}' ,db: all         ,addr: world     ,auth: deny  ,title: 'reject all other monitor access addr' }
  - {user: '${admin}'   ,db: all         ,addr: intra     ,auth: pwd   ,title: 'admin access via intranet with pwd'   }
  - {user: '${admin}'   ,db: all         ,addr: world     ,auth: deny  ,title: 'reject all other admin access addr'   }
  - {user: 'all'        ,db: all         ,addr: intra     ,auth: pwd   ,title: 'allow all user intra access with pwd' }

Security Enhancement

For those critical cases, we have a safe.yml template with the following hba rule set as a reference:

pg_default_hba_rules:             # postgres host-based auth rules by default
  - {user: '${dbsu}'    ,db: all         ,addr: local     ,auth: ident ,title: 'dbsu access via local os user ident'  }
  - {user: '${dbsu}'    ,db: replication ,addr: local     ,auth: ident ,title: 'dbsu replication from local os ident' }
  - {user: '${repl}'    ,db: replication ,addr: localhost ,auth: ssl   ,title: 'replicator replication from localhost'}
  - {user: '${repl}'    ,db: replication ,addr: intra     ,auth: ssl   ,title: 'replicator replication from intranet' }
  - {user: '${repl}'    ,db: postgres    ,addr: intra     ,auth: ssl   ,title: 'replicator postgres db from intranet' }
  - {user: '${monitor}' ,db: all         ,addr: localhost ,auth: pwd   ,title: 'monitor from localhost with password' }
  - {user: '${monitor}' ,db: all         ,addr: infra     ,auth: ssl   ,title: 'monitor from infra host with password'}
  - {user: '${admin}'   ,db: all         ,addr: infra     ,auth: ssl   ,title: 'admin @ infra nodes with pwd & ssl'   }
  - {user: '${admin}'   ,db: all         ,addr: world     ,auth: cert  ,title: 'admin @ everywhere with ssl & cert'   }
  - {user: '+dbrole_readonly',db: all    ,addr: localhost ,auth: ssl   ,title: 'pgbouncer read/write via local socket'}
  - {user: '+dbrole_readonly',db: all    ,addr: intra     ,auth: ssl   ,title: 'read/write biz user via password'     }
  - {user: '+dbrole_offline' ,db: all    ,addr: intra     ,auth: ssl   ,title: 'allow etl offline tasks from intranet'}
pgb_default_hba_rules:            # pgbouncer host-based authentication rules
  - {user: '${dbsu}'    ,db: pgbouncer   ,addr: local     ,auth: peer  ,title: 'dbsu local admin access with os ident'}
  - {user: 'all'        ,db: all         ,addr: localhost ,auth: pwd   ,title: 'allow all user local access with pwd' }
  - {user: '${monitor}' ,db: pgbouncer   ,addr: intra     ,auth: ssl   ,title: 'monitor access via intranet with pwd' }
  - {user: '${monitor}' ,db: all         ,addr: world     ,auth: deny  ,title: 'reject all other monitor access addr' }
  - {user: '${admin}'   ,db: all         ,addr: intra     ,auth: ssl   ,title: 'admin access via intranet with pwd'   }
  - {user: '${admin}'   ,db: all         ,addr: world     ,auth: deny  ,title: 'reject all other admin access addr'   }
  - {user: 'all'        ,db: all         ,addr: intra     ,auth: ssl   ,title: 'allow all user intra access with pwd' }