gmysql: support for caching_sha2_password through non-SSL connections

[clementmoulin]

• Program: Authoritative
• Issue type: Feature request

Short description

Currently using gmysql to connect to a mySQL through a non-SSL connection to an account using "caching_sha2_password" is not possible.

Usecase

PowerDNS with mysql backend on a secure link.

Description

Result: gmysql Connection failed: Unable to connect to database: ERROR 2061 (HY000): Authentication plugin 'caching_sha2_password' reported error: Authentication requires secure connection.

This is supported by mySQL, but requires that client retrieve RSA public key first. See https://dev.mysql.com/doc/refman/8.0/en/caching-sha2-pluggable-authentication.html (MYSQL_OPT_GET_SERVER_PUBLIC_KEY should be enabled)