/home/jobe path explicitly coded in LanguageTakss.php

[dirkcgrunwald]

On line 65 of LanguageTasks, the /home/jobe path is explicitly coded into the application. For various reasons (our /home is typically an auto-mounted mess) I specified a homedir of /local/jobe.

The failure mode was a little perplexing - jobe directories were in /tmp and readable by all other jobe submissions, which our pesky students quickly exploited.

Perhaps the documentation should indicate you need to use /home (or change the file) or it should be auto configured from the config file.

[trampgeek]

It sounds like /local/jobe did not actually exist. It's a "feature" of PHP's tempnam function that if you give it a directory that doesn't exist it may (!) "generate a file in the system's temporary directory, and return the full path to that file, including its name."

While a config file might be nice, I'm going to run with the simpler solution for now of a documented warning. I've now added the following, around line 65 of LanguageTask.php:

// WARNING: the /home/jobe/runs directory (below) is generated by the installer. 
// If you change that directory for some reason, make sure the directory
// exists, is owned by jobe, with group www-data (or whatever your web
// server user is) and has access rights of 771. If it's readable by
// the webserver or any of the jobe<n> users, running programs will be able
// to hoover up other students' submissions.

Thanks for the feedback, Dirk.

[stephenhouser]

I'm trying to parse this comment out. "...make sure the directory... with group www-data" but then "If it's readable by the webserver... hoover up other student's submissions."

In the first sentence it says to make it readable by the web server. Then in the second it says that if I do that, submissions are exposed. This is either contradictory or designed to enable hovering of other student's submissions?

NOTE: Apologies for the necro-post. I came across this while trying to sort out why I am getting permission denied errors in /home/jobe -- this issues does not appear related.

[trampgeek]

Thanks for posting your concerns. However, I'm wondering if you're reading a very old version of the code because the comment as it currently stands reads:

// WARNING: the /home/jobe/runs directory (below) is generated by the installer.
// If you change that directory for some reason, make sure the directory
// exists, is owned by jobe, with group www-data (or whatever your web
// server user is) and has access rights of 771. If it's readable by
// any of the jobe<n> users, running programs will be able
// to hoover up other students' submissions.

So the hoovering-up risk applies if the jobe<n > users can read the runs subdirectories, not if the webserver can read them. The webserver initiates the jobs but their ownership changes to jobe00, jobe01 etc when they're running.