GitHub's Gem Evaler
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Help make GitHub's gem build process more secure and robust!

There are two components associated with this:

* gem_builder.rb - Script that builds the gem
* gem_eval.rb - Sandboxed Sinatra app that evals ruby gemspecs


gem_builder.rb works as follows:

1) process() is called with a repository object and the path to the gemspec
2) If the spec is not in YAML, a request is made to the gem evaler (see below how it works)
3) A Gem::Specification object is created from the YAML gemspec and renamed with the user's login
4) The gem is built from the Gem::Specification using a monkey-patched version of RubyGems,
   so instead of grabbing the files from the filesystem, they're grabbed from the git repo

gem_eval.rb works as follows:

1) Receives a request with the repo location and the ruby gemspec
2) Makes a shallow clone of the repo and chdir's to that repo
3) Evals the spec in a separate thread with a higher $SAFE level
4) Converts spec to YAML


Goals
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* Lower the $SAFE level to allow methods like Dir.glob, but without compromising security.
* Never get another email from someone wondering why their gem didn't build