Render 404 when artifacts path is invalid

app/controllers/projects/artifacts_controller.rb

@@ -17,6 +17,7 @@ class Projects::ArtifactsController < Projects::ApplicationController
   def browse
     return render_404 unless build.artifacts?
     @path = build.artifacts_metadata_string_path(params[:path] || './')
+    return render_404 if @path.universe.empty?
   end
   private

lib/gitlab/ci/build/artifacts/metadata.rb

@@ -22,7 +22,7 @@ module Gitlab
             paths, metadata = [], []
             each do |line|
-              next unless line =~ %r{^#{Regexp.escape(@path)}[^/\s]+/?\s}
+              next unless line =~ %r{^#{Regexp.escape(@path)}[^/\s]*/?\s}
               path, meta = line.split(' ')
               paths.push(path)

spec/lib/gitlab/ci/build/artifacts/metadata_spec.rb

@@ -38,7 +38,8 @@ describe Gitlab::Ci::Build::Artifacts::Metadata do
       it 'matches correct paths' do
         expect(subject.first).
-          to contain_exactly 'other_artifacts_0.1.2/doc_sample.txt',
+          to contain_exactly 'other_artifacts_0.1.2/',
+                             'other_artifacts_0.1.2/doc_sample.txt',
                              'other_artifacts_0.1.2/another-subdirectory/'
       end
     end
@@ -48,7 +49,8 @@ describe Gitlab::Ci::Build::Artifacts::Metadata do
       it 'matches correct paths' do
         expect(subject.first).
-          to contain_exactly 'other_artifacts_0.1.2/another-subdirectory/empty_directory/',
+          to contain_exactly 'other_artifacts_0.1.2/another-subdirectory/',
+                             'other_artifacts_0.1.2/another-subdirectory/empty_directory/',
                              'other_artifacts_0.1.2/another-subdirectory/banana_sample.gif'
       end
     end