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认证 / HBA

Pigsty 中基于主机的身份认证 HBA（Host-Based Authentication）详解。
Pigsty 中基于主机的身份认证 HBA（Host-Based Authentication）详解。

Pigsty 中基于主机的身份认证 HBA（Host-Based Authentication）详解。

认证是 访问控制 与 权限系统 的基石，PostgreSQL拥有多种认证方法。

这里主要介绍 HBA：Host Based Authentication，HBA规则定义了哪些用户能够通过哪些方式从哪些地方访问哪些数据库。

客户端认证

要连接到PostgreSQL数据库，用户必须先经过认证（默认使用密码）。

您可以在连接字符串中提供密码（不安全）或使用PGPASSWORD环境变量或.pgpass文件传递密码。参考psql文档和PostgreSQL连接字符串以获取更多详细信息。

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>

例如，连接 Pigsty 默认的 meta 数据库，可以使用以下连接串：

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

默认配置下，Pigsty会启用服务端 SSL 加密，但不验证客户端 SSL 证书。要使用客户端SSL证书连接，你可以使用PGSSLCERT和PGSSLKEY环境变量或sslkey和sslcert参数提供客户端参数。

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

客户端证书（CN = 用户名）可以使用本地CA与cert.yml剧本签发。

定义HBA

在Pigsty中，有四个与HBA规则有关的参数：

这些都是 HBA 规则对象的数组，每个HBA规则都是以下两种形式之一的对象：

1. 原始形式

原始形式的 HBA 与 PostgreSQL pg_hba.conf 的格式几乎完全相同：

- 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

在这种形式中，rules 字段是字符串数组，每一行都是条原始形式的 HBA规则。title 字段会被渲染为一条注释，解释下面规则的作用。

role 字段用于说明该规则适用于哪些实例角色，当实例的pg_role与role相同时，HBA规则将被添加到这台实例的 HBA 中。

  • role: common的HBA规则将被添加到所有实例上。
  • role: primary 的 HBA 规则只会添加到主库实例上。
  • role: replica 的 HBA 规则只会添加到从库实例上。
  • role: offline的HBA规则将被添加到离线实例上（ pg_role = offline或pg_offline_query = true）

2. 别名形式

别名形式允许您用更简单清晰便捷的方式维护 HBA 规则：它用addr、auth、user和db 字段替换了 rules。 title 和 role 字段则仍然生效。

- 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 哪些IP地址段受本条规则影响？
    • world: 所有的IP地址
    • intra: 所有的内网IP地址段： '10.0.0.0/8', '172.16.0.0/12', '192.168.0.0/16'
    • infra: Infra节点的IP地址
    • admin: admin_ip 管理节点的IP地址
    • local: 本地 Unix Socket
    • localhost: 本地 Unix Socket 以及TCP 127.0.0.1/32 环回地址
    • cluster: 同一个 PostgresQL 集群所有成员的IP地址
    • <cidr>: 一个特定的 CIDR 地址块或IP地址
  • auth: how 本条规则指定的认证方式？
    • deny: 拒绝访问
    • trust: 直接信任，不需要认证
    • pwd: 密码认证，根据 pg_pwd_enc 参数选用 md5 或 scram-sha-256 认证
    • sha/scram-sha-256：强制使用 scram-sha-256 密码认证方式。
    • md5: md5 密码认证方式，但也可以兼容 scram-sha-256 认证，不建议使用。
    • ssl: 在密码认证 pwd 的基础上，强制要求启用SSL
    • ssl-md5: 在密码认证 md5 的基础上，强制要求启用SSL
    • ssl-sha: 在密码认证 sha 的基础上，强制要求启用SSL
    • os/ident: 使用操作系统用户的身份进行 ident 认证
    • peer: 使用 peer 认证方式，类似于 os ident
    • cert: 使用基于客户端SSL证书的认证方式，证书CN为用户名
  • user: who：哪些用户受本条规则影响？
  • db: which：哪些数据库受本条规则影响？
    • all: 所有数据库
    • replication: 允许建立复制连接（不指定特定数据库）
    • 某个特定的数据库

3. 定义位置

通常，全局的HBA定义在 all.vars 中，如果您想要修改全局默认的HBA规则，可以从 full.yml 模板中复制一份到 all.vars 中进行修改。

而集群特定的 HBA 规则定义在数据库的集群级配置中：

下面是一些集群HBA规则的定义例子：

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: '允许 dbuser_view 从基础设施节点密码访问所有库'}
      - { user: all         ,db: all    ,addr: 100.0.0.0/8  ,auth: pwd  ,title: '允许所有用户从K8S网段密码访问所有库'          }
      - { user: '${admin}'  ,db: world  ,addr: 0.0.0.0/0    ,auth: cert ,title: '允许管理员用户从任何地方用客户端证书登陆'       }

重载HBA

HBA 是一个静态的规则配置文件，修改后需要重载才能生效。默认的 HBA 规则集合因为不涉及 Role 与集群成员，所以通常不需要重载。

如果您设计的 HBA 使用了特定的实例角色限制，或者集群成员限制，那么当集群实例成员发生变化（新增/下线/主从切换），一部分HBA规则的生效条件/涉及范围发生变化，通常也需要重载HBA以反映最新变化。

要重新加载 postgres/pgbouncer 的 hba 规则：

bin/pgsql-hba <cls>                 # 重新加载集群 `<cls>` 的 hba 规则
bin/pgsql-hba <cls> ip1 ip2...      # 重新加载特定实例的 hba 规则

底层实际执行的 Ansible 剧本命令为：

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

默认HBA

Pigsty 有一套默认的 HBA 规则，对于绝大多数场景来说，它已经足够安全了。这些规则使用别名形式，因此基本可以自我解释。

pg_default_hba_rules:             # postgres 全局默认的HBA规则
  - {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: '${admin}'   ,db: all         ,addr: world     ,auth: ssl   ,title: 'admin @ everywhere with ssl & pwd'   }
  - {user: '+dbrole_readonly',db: all    ,addr: localhost ,auth: pwd   ,title: 'pgbouncer read/write via local socket'}
  - {user: '+dbrole_readonly',db: all    ,addr: intra     ,auth: pwd   ,title: 'read/write biz user via password'     }
  - {user: '+dbrole_offline' ,db: all    ,addr: intra     ,auth: pwd   ,title: 'allow etl offline tasks from intranet'}
pgb_default_hba_rules:            # pgbouncer 全局默认的HBA规则
  - {user: '${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' }
示例：渲染 pg_hba.conf 
#==============================================================#
# File      :   pg_hba.conf
# Desc      :   Postgres HBA Rules for pg-meta-1 [primary]
# Time      :   2023-01-11 15:19
# Host      :   pg-meta-1 @ 10.10.10.10:5432
# Path      :   /pg/data/pg_hba.conf
# Note      :   ANSIBLE MANAGED, DO NOT CHANGE!
# Author    :   Ruohang Feng ([email protected])
# License   :   AGPLv3
#==============================================================#

# addr alias
# local     : /var/run/postgresql
# admin     : 10.10.10.10
# infra     : 10.10.10.10
# intra     : 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16

# user alias
# dbsu    :  postgres
# repl    :  replicator
# monitor :  dbuser_monitor
# admin   :  dbuser_dba

# dbsu access via local os user ident [default]
local    all                postgres                              ident

# dbsu replication from local os ident [default]
local    replication        postgres                              ident

# replicator replication from localhost [default]
local    replication        replicator                            scram-sha-256
host     replication        replicator         127.0.0.1/32       scram-sha-256

# replicator replication from intranet [default]
host     replication        replicator         10.0.0.0/8         scram-sha-256
host     replication        replicator         172.16.0.0/12      scram-sha-256
host     replication        replicator         192.168.0.0/16     scram-sha-256

# replicator postgres db from intranet [default]
host     postgres           replicator         10.0.0.0/8         scram-sha-256
host     postgres           replicator         172.16.0.0/12      scram-sha-256
host     postgres           replicator         192.168.0.0/16     scram-sha-256

# monitor from localhost with password [default]
local    all                dbuser_monitor                        scram-sha-256
host     all                dbuser_monitor     127.0.0.1/32       scram-sha-256

# monitor from infra host with password [default]
host     all                dbuser_monitor     10.10.10.10/32     scram-sha-256

# admin @ infra nodes with pwd & ssl [default]
hostssl  all                dbuser_dba         10.10.10.10/32     scram-sha-256

# admin @ everywhere with ssl & pwd [default]
hostssl  all                dbuser_dba         0.0.0.0/0          scram-sha-256

# pgbouncer read/write via local socket [default]
local    all                +dbrole_readonly                      scram-sha-256
host     all                +dbrole_readonly   127.0.0.1/32       scram-sha-256

# read/write biz user via password [default]
host     all                +dbrole_readonly   10.0.0.0/8         scram-sha-256
host     all                +dbrole_readonly   172.16.0.0/12      scram-sha-256
host     all                +dbrole_readonly   192.168.0.0/16     scram-sha-256

# allow etl offline tasks from intranet [default]
host     all                +dbrole_offline    10.0.0.0/8         scram-sha-256
host     all                +dbrole_offline    172.16.0.0/12      scram-sha-256
host     all                +dbrole_offline    192.168.0.0/16     scram-sha-256

# allow application database intranet access [common] [DISABLED]
#host    kong            dbuser_kong         10.0.0.0/8          md5
#host    bytebase        dbuser_bytebase     10.0.0.0/8          md5
#host    grafana         dbuser_grafana      10.0.0.0/8          md5
示例: 渲染 pgb_hba.conf 
#==============================================================#
# File      :   pgb_hba.conf
# Desc      :   Pgbouncer HBA Rules for pg-meta-1 [primary]
# Time      :   2023-01-11 15:28
# Host      :   pg-meta-1 @ 10.10.10.10:5432
# Path      :   /etc/pgbouncer/pgb_hba.conf
# Note      :   ANSIBLE MANAGED, DO NOT CHANGE!
# Author    :   Ruohang Feng ([email protected])
# License   :   AGPLv3
#==============================================================#

# PGBOUNCER HBA RULES FOR pg-meta-1 @ 10.10.10.10:6432
# ansible managed: 2023-01-11 14:30:58

# addr alias
# local     : /var/run/postgresql
# admin     : 10.10.10.10
# infra     : 10.10.10.10
# intra     : 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16

# user alias
# dbsu    :  postgres
# repl    :  replicator
# monitor :  dbuser_monitor
# admin   :  dbuser_dba

# dbsu local admin access with os ident [default]
local    pgbouncer          postgres                              peer

# allow all user local access with pwd [default]
local    all                all                                   scram-sha-256
host     all                all                127.0.0.1/32       scram-sha-256

# monitor access via intranet with pwd [default]
host     pgbouncer          dbuser_monitor     10.0.0.0/8         scram-sha-256
host     pgbouncer          dbuser_monitor     172.16.0.0/12      scram-sha-256
host     pgbouncer          dbuser_monitor     192.168.0.0/16     scram-sha-256

# reject all other monitor access addr [default]
host     all                dbuser_monitor     0.0.0.0/0          reject

# admin access via intranet with pwd [default]
host     all                dbuser_dba         10.0.0.0/8         scram-sha-256
host     all                dbuser_dba         172.16.0.0/12      scram-sha-256
host     all                dbuser_dba         192.168.0.0/16     scram-sha-256

# reject all other admin access addr [default]
host     all                dbuser_dba         0.0.0.0/0          reject

# allow all user intra access with pwd [default]
host     all                all                10.0.0.0/8         scram-sha-256
host     all                all                172.16.0.0/12      scram-sha-256
host     all                all                192.168.0.0/16     scram-sha-256

安全加固

对于那些需要更高安全性的场合，我们提供了一个安全加固的配置模板 security.yml，使用了以下的默认 HBA 规则集：

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' }

更多信息，请参考安全加固一节。