PgAuthProxy

PgAuthProxy is a PostgreSQL gateway with customizable authentication. It provides single entrypoint for various database servers with credentials mapping capability.

Installation

go install github.com/KnifeMaster007/pgAuthProxy

Core concepts

When client connects PgAuthProxy, it handles the connection this way:

1. Receives startup message from the client, which includes the names of the user and of the database
2. Responds to client with Authentication Request message
3. Client responds with password message
4. PgAuthProxy executes user-defined authenticator command
5. If authenticator command execution succeeded, PgAuthProxy initiates connection to host, provided by authenticator
6. If connection to target succeeded, PgAuthProxy sends startup message with parameters provided by the authenticator(user, database, etc.)
7. On authentication request from target host, PgAuthProxy sends credential, provided by authenticator
8. If authentication with the target is successful, PgAuthProxy just forwards any further messages between the client and target host

Usage

pgAuthProxy [flags]

Flags:
      --clear-passwd    use cleartext password instead of MD5-hashed
      --config string   configuration file path
  -h, --help            help for pgAuthProxy
      --listen string   bind address (default ":5432")

Configuration file

listen: 0.0.0.0:15432                             # bind address (default ":5432")

authenticator:
  cleartext_password: false                       # use cleartext password instead of MD5-hashed
  cmd: ["authenticator.py", "--md5-passwords"]    # authentication command

Authenticator executable call conventions

Authenticator must process startup message parameters and credentials, provided by user, and respond with startup message and credentials for target database server

PgAuthProxy launches authenticator on each connection, passes input parameters to STDIN and reads target database parameters from an authenticator's STDOUT. Non-zero exit code treated as authentication error.

Example

Authenticator input

user=testuser
database=testuser
application_name=psql
client_encoding=UTF8
_SOURCE_CRED=md55fa959c75491e1ce08541c50bc3ac3c4
_SOURCE_SALT=2182654f

If cleartext passwords is enabled, _SOURCE_CRED will contain password, _SOURCE_SALT will be 00000000

Authenticator output

user=postgres
database=postgres
application_name=psql(proxied for testuser)
client_encoding=UTF8
_META_TARGET_HOST=pgbouncer.prod:5432
_META_TARGET_CRED=md53670464b1b43f39455d2637b187f9245

Limitations

• SSL is not supported yet
• Cleartext password authentication with backend is not supported