Extract GitLab Pages using RubyZip

RubyZip allows us to perform strong validation of
expanded paths where we do extract file.

We introduce the following additional checks
to extract routines:

1. None of path components can be symlinked,
2. We drop privileges support for directories,
3. Symlink source needs to point within the target directory,
   like `public/`,
4. The symlink source needs to exist ahead of time.

1 files changed, 1 insertions, 0 deletions

diff --git a/Gemfile b/Gemfile
index 943b0260dcb..40950fbfb43 100644
--- a/Gemfile
+++ b/Gemfile
@@ -57,6 +57,7 @@ gem 'u2f', '~> 0.2.1'
 
 # GitLab Pages
 gem 'validates_hostname', '~> 1.0.6'
+gem 'rubyzip', '~> 1.2.2', require: false
 
 # Browser detection
 gem 'browser', '~> 2.5'