Avoid crash when trying to parse string with invalid UTF-8 sequence

app/validators/dynamic_path_validator.rb

@@ -6,16 +6,21 @@
 # Values are checked for formatting and exclusion from a list of illegal path
 # names.
 class DynamicPathValidator < ActiveModel::EachValidator
+  extend Gitlab::Git::EncodingHelper
+
   class << self
     def valid_user_path?(path)
+      encode!(path)
       "#{path}/" =~ Gitlab::PathRegex.root_namespace_path_regex
     end
 
     def valid_group_path?(path)
+      encode!(path)
       "#{path}/" =~ Gitlab::PathRegex.full_namespace_path_regex
     end
 
     def valid_project_path?(path)
+      encode!(path)
       "#{path}/" =~ Gitlab::PathRegex.full_project_path_regex
     end
   end

spec/lib/gitlab/git/encoding_helper_spec.rb

@@ -2,7 +2,7 @@ require "spec_helper"
 
 describe Gitlab::Git::EncodingHelper do
   let(:ext_class) { Class.new { extend Gitlab::Git::EncodingHelper } }
-  let(:binary_string) { File.join(SEED_STORAGE_PATH, 'gitlab_logo.png') }
+  let(:binary_string) { File.read(Rails.root + "spec/fixtures/dk.png") }
 
   describe '#encode!' do
     [

spec/validators/dynamic_path_validator_spec.rb

@@ -3,6 +3,28 @@ require 'spec_helper'
 describe DynamicPathValidator do
   let(:validator) { described_class.new(attributes: [:path]) }
 
+  def expect_handles_invalid_utf8
+    expect { yield('\255invalid') }.to be_falsey
+  end
+
+  describe '.valid_user_path' do
+    it 'handles invalid utf8' do
+      expect(described_class.valid_user_path?("a\0weird\255path")).to be_falsey
+    end
+  end
+
+  describe '.valid_group_path' do
+    it 'handles invalid utf8' do
+      expect(described_class.valid_group_path?("a\0weird\255path")).to be_falsey
+    end
+  end
+
+  describe '.valid_project_path' do
+    it 'handles invalid utf8' do
+      expect(described_class.valid_project_path?("a\0weird\255path")).to be_falsey
+    end
+  end
+
   describe '#path_valid_for_record?' do
     context 'for project' do
       it 'calls valid_project_path?' do