Validate route map

app/models/project.rb

@@ -1312,7 +1312,7 @@ class Project < ActiveRecord::Base
         deployments_query = with_tags ? 'ref = ? OR tag IS TRUE' : 'ref = ?'
         deployments.where(deployments_query, ref.to_s)
       elsif commit
-        deps = deployments.where(sha: commit.sha)
+        deployments.where(sha: commit.sha)
       else
         Deployment.none
       end
@@ -1348,13 +1348,9 @@ class Project < ActiveRecord::Base
         data = repository.route_map_file(sha)
         next unless data
 
-        # TODO: Validate
-        YAML.safe_load(data).map do |mapping|
-          {
-            source: Regexp.new("^#{mapping['source'][1...-1]}$"),
-            public: mapping['public']
-          }
-        end
+        Gitlab::RouteMap.new(data)
+      rescue Gitlab::RouteMap::FormatError
+        nil
       end
     end
 
@@ -1365,10 +1361,7 @@ class Project < ActiveRecord::Base
     map = route_map_for_commit(commit_sha)
     return unless map
 
-    mapping = map.find { |mapping| path =~ mapping[:source] }
-    return unless mapping
-
-    path.sub(mapping[:source], mapping[:public])
+    map.public_path_for_source_path(path)
   end
 
   private

app/views/projects/blob/_actions.html.haml

 .btn-group
   = view_on_environment_btn(@commit.sha, @path, @environment) if @environment
-  
+
 .btn-group.tree-btn-group
   = link_to 'Raw', namespace_project_raw_path(@project.namespace, @project, @id),
       class: 'btn btn-sm', target: '_blank'

lib/gitlab/route_map.rb

+module Gitlab
+  class RouteMap
+    class FormatError < StandardError; end
+
+    def initialize(data)
+      begin
+        entries = YAML.safe_load(data)
+      rescue
+        raise FormatError, 'Route map needs to be valid YAML'
+      end
+
+      raise FormatError, 'Route map needs to be an array' unless entries.is_a?(Array)
+
+      @map = entries.map { |entry| parse_entry(entry) }
+    end
+
+    def public_path_for_source_path(path)
+      mapping = @map.find { |mapping| path =~ mapping[:source] }
+      return unless mapping
+
+      path.sub(mapping[:source], mapping[:public])
+    end
+
+    private
+
+    def parse_entry(entry)
+      raise FormatError, 'Route map entry needs to be a hash' unless entry.is_a?(Hash)
+      raise FormatError, 'Route map entry requires a source key' unless entry.has_key?('source')
+      raise FormatError, 'Route map entry requires a public key' unless entry.has_key?('public')
+
+      source_regexp = entry['source']
+      public_path = entry['public']
+
+      unless source_regexp.start_with?('/') && source_regexp.end_with?('/')
+        raise FormatError, 'Route map entry source needs to start and end in a slash (/)'
+      end
+
+      source_regexp = source_regexp[1...-1].gsub('\/', '/')
+
+      begin
+        source_regexp = Regexp.new("^#{source_regexp}$")
+      rescue RegexpError => e
+        raise FormatError, "Route map entry source needs to be a valid regular expression: #{e}"
+      end
+
+      {
+        source: source_regexp,
+        public: public_path
+      }
+    end
+  end
+end