Bug #47589 Chassis should refuse configfile readable to everyone

Description:
The proxy chassis currently accepts starting with config files that are readable to everyone. This is a security issue since the file contains the users plaintext password.

How to repeat:
* Create your default config file, i.e myproxycfg.ini
* chmod 777 myproxycfg.ini
* ./bin/mysql-proxy --defaults-file=/path/to/myproxycfg.ini

... which starts fine. Ideally this should result in an error exit and sensible user error message.

* chmod 600 myproxycfg.ini
* ./bin/mysql-proxy --defaults-file=/path/to/myproxycfg.ini

starts fine - as expected.

Suggested fix:
* on startup, check permissions for config file, and exit with error if incorrect permissions set.

Thank you for the report.

Verified as described.

Keith Russell writes: 
Patch available in build.

Diego Medina writes: 
Verified fixed on 0.8.0

A note has been added to the 0.8.0 changelog, the documentation already mentioned this requirement: 

        MySQL Proxy would load a configuration file with unsafe                                       
        permissions, which could allow password information to be                                     
        exposed through the configuration file. MySQL Proxy now                                       
        refuses to load a file with unsafe permissions.