Overview
"Perhaps I know more of these pursuers than you do. You fear them, but you do not fear them enough, yet."
Games::Golf does not have adequate built-in safeguards against malicious player code. Module users should make themselves familiar with the limitations - and make the appropriate allowances when using or creating scripts.
The nature of golfing implies programs are rather cryptic character sequences, known as "line noise". Good golfers pride themselves on lowering the Signal to Noise ratio to virtually zero. Unfortunately, this means the difference between safe and malicious code can be almost impossible to identify.
It is inevitable that the hosts of golf competitions will favour fully automated testing and submission. Hopefully, this module will be used for implementing these systems, although an adequate security model will have to be devised.
Perhaps, in the future many of the common security issues will be resolved. Unfortunately, even when they are, the prudent should not rely on them. In short, this module runs untrustworthy code without restriction and we deny responsibility for limiting the damage. (For more information, please read the license).
The security problems are numerous, and hopefully by now the reader is truly paranoid. Below we address several specific concerns and how the risk might be averted.
What you need
"We cannot count on getting anything to eat between here and Rivendell, except what we take with us, and we ought to take plenty to spare."
There are some essentials for running a secure system...
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An unused computer
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A secure operating system (not Windows)
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time
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knowledge
The majority of users shall have either Windows or Unix, however when security becomes a serious concern Unix is the best bet. The average Windows system is unrealistically geared towards a world devoid of security threats - and that utopia is slipping away daily.
> Enlist help of others if not a Unix wizard
> Welcome Windows security suggestions - despite the anti-recommend.
A question of trust
"...there are some folk in Bree who are not to be trusted."
Test
The test suite for a particular hole is loaded via:
my $test = Games::Golf::TestSuite->new("hole.t");
where hole.t is a Perl script that implements the tests.
We have not used the Safe module, yet the script is evaluated via eval(). This means that hole.t can change package variables in any package it pleases.
Unless we use another scheme then you will need to ensure the safety of the hole.t script. Hence, make sure that it cannot be modified according to the file permissions of the script under test. We recommend that it is set to read only in the ownership of another user.
Marking out the turf
"We will all remain together and bar this window and the door."
> chroot environment
> user permissions (keep separate from the test script)
> create a user/group account for testing
Cutting connections
"This is where we leave the open and take to cover"
> firewall to restrict all ports
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Cleaning up
"Hadn't we better clear out quick, Mr Strider?"
> deleting temporaries and unwanted files after each iteration
Miscellaneous
"I had to study _you_ first, and make sure of you. The Enemy has set traps for me before now."