PostgreSQL10.0preview功能增強-客戶端ACL（pg_hba.conf動態檢視）

標籤

PostgreSQL , ACL , pg_hba.conf

---

背景

pg_hba.conf檔案是用於控制客戶端訪問PostgreSQL資料庫的防火牆配置（ACL），以往我們要了解資料庫配置的ACL，必須開啟這個檔案進行檢視。

例如

cat $PGDATA/pg_hba.conf  
  
# PostgreSQL Client Authentication Configuration File  
# ===================================================  
#  
# Refer to the "Client Authentication" section in the PostgreSQL  
# documentation for a complete description of this file.  A short  
# synopsis follows.  
#  
# This file controls: which hosts are allowed to connect, how clients  
# are authenticated, which PostgreSQL user names they can use, which  
# databases they can access.  Records take one of these forms:  
#  
# local      DATABASE  USER  METHOD  [OPTIONS]  
# host       DATABASE  USER  ADDRESS  METHOD  [OPTIONS]  
# hostssl    DATABASE  USER  ADDRESS  METHOD  [OPTIONS]  
# hostnossl  DATABASE  USER  ADDRESS  METHOD  [OPTIONS]  
#  
# (The uppercase items must be replaced by actual values.)  
#  
# The first field is the connection type: "local" is a Unix-domain  
# socket, "host" is either a plain or SSL-encrypted TCP/IP socket,  
# "hostssl" is an SSL-encrypted TCP/IP socket, and "hostnossl" is a  
# plain TCP/IP socket.  
#  
# DATABASE can be "all", "sameuser", "samerole", "replication", a  
# database name, or a comma-separated list thereof. The "all"  
# keyword does not match "replication". Access to replication  
# must be enabled in a separate record (see example below).  
#  
# USER can be "all", a user name, a group name prefixed with "+", or a  
# comma-separated list thereof.  In both the DATABASE and USER fields  
# you can also write a file name prefixed with "@" to include names  
# from a separate file.  
#  
# ADDRESS specifies the set of hosts the record matches.  It can be a  
# host name, or it is made up of an IP address and a CIDR mask that is  
# an integer (between 0 and 32 (IPv4) or 128 (IPv6) inclusive) that  
# specifies the number of significant bits in the mask.  A host name  
# that starts with a dot (.) matches a suffix of the actual host name.  
# Alternatively, you can write an IP address and netmask in separate  
# columns to specify the set of hosts.  Instead of a CIDR-address, you  
# can write "samehost" to match any of the server`s own IP addresses,  
# or "samenet" to match any address in any subnet that the server is  
# directly connected to.  
#  
# METHOD can be "trust", "reject", "md5", "password", "gss", "sspi",  
# "ident", "peer", "pam", "ldap", "radius" or "cert".  Note that  
# "password" sends passwords in clear text; "md5" is preferred since  
# it sends encrypted passwords.  
#  
# OPTIONS are a set of options for the authentication in the format  
# NAME=VALUE.  The available options depend on the different  
# authentication methods -- refer to the "Client Authentication"  
# section in the documentation for a list of which options are  
# available for which authentication methods.  
#  
# Database and user names containing spaces, commas, quotes and other  
# special characters must be quoted.  Quoting one of the keywords  
# "all", "sameuser", "samerole" or "replication" makes the name lose  
# its special character, and just match a database or username with  
# that name.  
#  
# This file is read on server startup and when the postmaster receives  
# a SIGHUP signal.  If you edit the file on a running system, you have  
# to SIGHUP the postmaster for the changes to take effect.  You can  
# use "pg_ctl reload" to do that.  
  
# Put your actual configuration here  
# ----------------------------------  
#  
# If you want to allow non-local connections, you need to add more  
# "host" records.  In that case you will also need to make PostgreSQL  
# listen on a non-local interface via the listen_addresses  
# configuration parameter, or via the -i or -h command line switches.  
  
# CAUTION: Configuring the system for local "trust" authentication  
# allows any local user to connect as any PostgreSQL user, including  
# the database superuser.  If you do not trust all your local users,  
# use another authentication method.  
  
# TYPE  DATABASE        USER            ADDRESS                 METHOD  
  
# "local" is for Unix domain socket connections only  
local   all             all                                     trust  
# IPv4 local connections:  
host    all             all             127.0.0.1/32            trust  
# IPv6 local connections:  
host    all             all             ::1/128                 trust  
# Allow replication connections from localhost, by a user with the  
# replication privilege.  
local   replication     postgres                                trust  
host    replication     postgres        127.0.0.1/32            trust  
host    replication     postgres        ::1/128                 trust  
host all all 0.0.0.0/0 trust  

PostgreSQL 10.0增加了一個檢視pg_hba.conf的檢視，允許超級使用者查詢。

方便DBA的排錯工作。

Table 51.70. pg_hba_file_rules Columns

Name	Type	Description
line_number	integer	Line number of this rule in pg_hba.conf
type	text	Type of connection
database	text[]	List of database name(s) to which this rule applies
user_name	text[]	List of user and group name(s) to which this rule applies
address	text	Host name or IP address, or one of all, samehost, or samenet, or null for local connections
netmask	text	IP address mask, or null if not applicable
auth_method	text	Authentication method
options	text[]	Options specified for authentication method, if any
error	text	If not null, an error message indicating why this line could not be processed

詳見

Hi All,  
  
While working on pg_hba_lookup function that can be used to lookup for an client  
authentication that can be matched for given input parameters, Tom raised some  
concrete use case issues in the following mail [1]. In this same  
thread, he raised  
some advantages of having a view similar like pg_file_settings view  
for pg_hba.conf  
also.  
  
Here I attached a patch that implements the pg_hba_file_settings view  
that displays  
all the rows in pg_hba.conf. In case if any error exists in the  
authentication rule, the  
corresponding error is displayed similar like pg_file_settings.  
  
This view can be used to verify whether there exists any problems or  
not in the pg_hba.conf  
before it reloads into the system. This view cannot be used to check  
similar like  
pg_hba_lookup function to find out which rule maps to the  
corresponding input connection.  
  
comments?  
  
[1] - https://www.postgresql.org/message-id/28434.1468246200%40sss.pgh.pa.us  
  
Regards,  
Hari Babu  
Fujitsu Australia  

參考

https://www.postgresql.org/docs/devel/static/view-pg-hba-file-rules.html