Merge branch 'dm-http-hostname-override' into 'master'

Protect Gitlab::HTTP against DNS rebinding attack

See merge request gitlab/gitlabhq!3071

app/helpers/application_settings_helper.rb

@@ -160,6 +160,7 @@ module ApplicationSettingsHelper
       :akismet_api_key,
       :akismet_enabled,
       :allow_local_requests_from_hooks_and_services,
+      :dns_rebinding_protection_enabled,
       :archive_builds_in_human_readable,
       :authorized_keys_enabled,
       :auto_devops_enabled,

app/models/application_setting_implementation.rb

@@ -21,6 +21,7 @@ module ApplicationSettingImplementation
         after_sign_up_text: nil,
         akismet_enabled: false,
         allow_local_requests_from_hooks_and_services: false,
+        dns_rebinding_protection_enabled: true,
         authorized_keys_enabled: true, # TODO default to false if the instance is configured to use AuthorizedKeysCommand
         container_registry_token_expire_delay: 5,
         default_artifacts_expire_in: '30 days',

app/views/admin/application_settings/_outbound.html.haml

@@ -8,4 +8,12 @@
         = f.label :allow_local_requests_from_hooks_and_services, class: 'form-check-label' do
           Allow requests to the local network from hooks and services
 
+    .form-group
+      .form-check
+        = f.check_box :dns_rebinding_protection_enabled, class: 'form-check-input'
+        = f.label :dns_rebinding_protection_enabled, class: 'form-check-label' do
+          = _('Enforce DNS rebinding attack protection')
+        %span.form-text.text-muted
+          = _('Resolves IP addresses once and uses them to submit requests')
+
   = f.submit 'Save changes', class: "btn btn-success"

changelogs/unreleased/dm-http-hostname-override.yml

+---
+title: Protect Gitlab::HTTP against DNS rebinding attack
+merge_request:
+author:
+type: security

config/initializers/hipchat_client_patch.rb

@@ -2,14 +2,14 @@
 # This monkey patches the HTTParty used in https://github.com/hipchat/hipchat-rb.
 module HipChat
   class Client
-    connection_adapter ::Gitlab::ProxyHTTPConnectionAdapter
+    connection_adapter ::Gitlab::HTTPConnectionAdapter
   end
 
   class Room
-    connection_adapter ::Gitlab::ProxyHTTPConnectionAdapter
+    connection_adapter ::Gitlab::HTTPConnectionAdapter
   end
 
   class User
-    connection_adapter ::Gitlab::ProxyHTTPConnectionAdapter
+    connection_adapter ::Gitlab::HTTPConnectionAdapter
   end
 end

config/initializers/http_hostname_override.rb

+# This override allows passing `@hostname_override` to the SNI protocol,
+# which is used to lookup the correct SSL certificate in the
+# request handshake process.
+#
+# Given we've forced the HTTP request to be sent to the resolved
+# IP address in a few scenarios (e.g.: `Gitlab::HTTP` through
+# `Gitlab::UrlBlocker.validate!`), we need to provide the _original_
+# hostname via SNI in order to have a clean connection setup.
+#
+# This is ultimately needed in order to avoid DNS rebinding attacks
+# through HTTP requests.
+#
+class OpenSSL::SSL::SSLContext
+  attr_accessor :hostname_override
+end
+
+class OpenSSL::SSL::SSLSocket
+  module HostnameOverride
+    # rubocop: disable Gitlab/ModuleWithInstanceVariables
+    def hostname=(hostname)
+      super(@context.hostname_override || hostname)
+    end
+
+    def post_connection_check(hostname)
+      super(@context.hostname_override || hostname)
+    end
+    # rubocop: enable Gitlab/ModuleWithInstanceVariables
+  end
+
+  prepend HostnameOverride
+end
+
+class Net::HTTP
+  attr_accessor :hostname_override
+  SSL_IVNAMES << :@hostname_override
+  SSL_ATTRIBUTES << :hostname_override
+
+  module HostnameOverride
+    def addr_port
+      return super unless hostname_override
+
+      addr = hostname_override
+      default_port = use_ssl? ? Net::HTTP.https_default_port : Net::HTTP.http_default_port
+      default_port == port ? addr : "#{addr}:#{port}"
+    end
+  end
+
+  prepend HostnameOverride
+end

db/migrate/20190529142545_add_dns_rebinding_protection_enabled_to_application_settings.rb

+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddDnsRebindingProtectionEnabledToApplicationSettings < ActiveRecord::Migration[5.1]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default(:application_settings, :dns_rebinding_protection_enabled,
+                            :boolean,
+                            default: true,
+                            allow_null: false)
+  end
+
+  def down
+    remove_column(:application_settings, :dns_rebinding_protection_enabled)
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20190524062810) do
+ActiveRecord::Schema.define(version: 20190529142545) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -193,6 +193,7 @@ ActiveRecord::Schema.define(version: 20190524062810) do
     t.integer "elasticsearch_replicas", default: 1, null: false
     t.text "encrypted_lets_encrypt_private_key"
     t.text "encrypted_lets_encrypt_private_key_iv"
+    t.boolean "dns_rebinding_protection_enabled", default: true, null: false
     t.index ["usage_stats_set_by_user_id"], name: "index_application_settings_on_usage_stats_set_by_user_id", using: :btree
   end
 

lib/gitlab.rb

@@ -40,6 +40,7 @@ module Gitlab
   SUBDOMAIN_REGEX = %r{\Ahttps://[a-z0-9]+\.gitlab\.com\z}.freeze
   VERSION = File.read(root.join("VERSION")).strip.freeze
   INSTALLATION_TYPE = File.read(root.join("INSTALLATION_TYPE")).strip.freeze
+  HTTP_PROXY_ENV_VARS = %w(http_proxy https_proxy HTTP_PROXY HTTPS_PROXY).freeze
 
   def self.com?
     # Check `gl_subdomain?` as well to keep parity with gitlab.com
@@ -66,6 +67,10 @@ module Gitlab
     end
   end
 
+  def self.http_proxy_env?
+    HTTP_PROXY_ENV_VARS.any? { |name| ENV[name] }
+  end
+
   def self.process_name
     return 'sidekiq' if Sidekiq.server?
     return 'console' if defined?(Rails::Console)

lib/gitlab/http.rb

@@ -11,7 +11,7 @@ module Gitlab
 
     include HTTParty # rubocop:disable Gitlab/HTTParty
 
-    connection_adapter ProxyHTTPConnectionAdapter
+    connection_adapter HTTPConnectionAdapter
 
     def self.perform_request(http_method, path, options, &block)
       super

lib/gitlab/proxy_http_connection_adapter.rb → lib/gitlab/http_connection_adapter.rb

@@ -10,17 +10,19 @@
 #
 # This option will take precedence over the global setting.
 module Gitlab
-  class ProxyHTTPConnectionAdapter < HTTParty::ConnectionAdapter
+  class HTTPConnectionAdapter < HTTParty::ConnectionAdapter
     def connection
-      unless allow_local_requests?
-        begin
-          Gitlab::UrlBlocker.validate!(uri, allow_local_network: false)
-        rescue Gitlab::UrlBlocker::BlockedUrlError => e
-          raise Gitlab::HTTP::BlockedUrlError, "URL '#{uri}' is blocked: #{e.message}"
-        end
+      begin
+        @uri, hostname = Gitlab::UrlBlocker.validate!(uri, allow_local_network: allow_local_requests?,
+                                                           allow_localhost: allow_local_requests?,
+                                                           dns_rebind_protection: dns_rebind_protection?)
+      rescue Gitlab::UrlBlocker::BlockedUrlError => e
+        raise Gitlab::HTTP::BlockedUrlError, "URL '#{uri}' is blocked: #{e.message}"
       end
 
-      super
+      super.tap do |http|
+        http.hostname_override = hostname if hostname
+      end
     end
 
     private
@@ -29,6 +31,12 @@ module Gitlab
       options.fetch(:allow_local_requests, allow_settings_local_requests?)
     end
 
+    def dns_rebind_protection?
+      return false if Gitlab.http_proxy_env?
+
+      Gitlab::CurrentSettings.dns_rebinding_protection_enabled?
+    end
+
     def allow_settings_local_requests?
       Gitlab::CurrentSettings.allow_local_requests_from_hooks_and_services?
     end

lib/gitlab/url_blocker.rb

@@ -8,38 +8,68 @@ module Gitlab
     BlockedUrlError = Class.new(StandardError)
 
     class << self
-      def validate!(url, ports: [], schemes: [], allow_localhost: false, allow_local_network: true, ascii_only: false, enforce_user: false, enforce_sanitization: false)
-        return true if url.nil?
+      # Validates the given url according to the constraints specified by arguments.
+      #
+      # ports - Raises error if the given URL port does is not between given ports.
+      # allow_localhost - Raises error if URL resolves to a localhost IP address and argument is true.
+      # allow_local_network - Raises error if URL resolves to a link-local address and argument is true.
+      # ascii_only - Raises error if URL has unicode characters and argument is true.
+      # enforce_user - Raises error if URL user doesn't start with alphanumeric characters and argument is true.
+      # enforce_sanitization - Raises error if URL includes any HTML/CSS/JS tags and argument is true.
+      #
+      # Returns an array with [<uri>, <original-hostname>].
+      # rubocop:disable Metrics/CyclomaticComplexity
+      # rubocop:disable Metrics/ParameterLists
+      def validate!(
+        url,
+        ports: [],
+        schemes: [],
+        allow_localhost: false,
+        allow_local_network: true,
+        ascii_only: false,
+        enforce_user: false,
+        enforce_sanitization: false,
+        dns_rebind_protection: true)
+        # rubocop:enable Metrics/CyclomaticComplexity
+        # rubocop:enable Metrics/ParameterLists
+
+        return [nil, nil] if url.nil?
 
         # Param url can be a string, URI or Addressable::URI
         uri = parse_url(url)
 
         validate_html_tags!(uri) if enforce_sanitization
 
-        # Allow imports from the GitLab instance itself but only from the configured ports
-        return true if internal?(uri)
-
+        hostname = uri.hostname
         port = get_port(uri)
-        validate_scheme!(uri.scheme, schemes)
-        validate_port!(port, ports) if ports.any?
-        validate_user!(uri.user) if enforce_user
-        validate_hostname!(uri.hostname)
-        validate_unicode_restriction!(uri) if ascii_only
+
+        unless internal?(uri)
+          validate_scheme!(uri.scheme, schemes)
+          validate_port!(port, ports) if ports.any?
+          validate_user!(uri.user) if enforce_user
+          validate_hostname!(hostname)
+          validate_unicode_restriction!(uri) if ascii_only
+        end
 
         begin
-          addrs_info = Addrinfo.getaddrinfo(uri.hostname, port, nil, :STREAM).map do |addr|
+          addrs_info = Addrinfo.getaddrinfo(hostname, port, nil, :STREAM).map do |addr|
             addr.ipv6_v4mapped? ? addr.ipv6_to_ipv4 : addr
           end
         rescue SocketError
-          return true
+          return [uri, nil]
         end
 
+        protected_uri_with_hostname = enforce_uri_hostname(addrs_info, uri, hostname, dns_rebind_protection)
+
+        # Allow url from the GitLab instance itself but only for the configured hostname and ports
+        return protected_uri_with_hostname if internal?(uri)
+
         validate_localhost!(addrs_info) unless allow_localhost
         validate_loopback!(addrs_info) unless allow_localhost
         validate_local_network!(addrs_info) unless allow_local_network
         validate_link_local!(addrs_info) unless allow_local_network
 
-        true
+        protected_uri_with_hostname
       end
 
       def blocked_url?(*args)
@@ -52,6 +82,25 @@ module Gitlab
 
       private
 
+      # Returns the given URI with IP address as hostname and the original hostname respectively
+      # in an Array.
+      #
+      # It checks whether the resolved IP address matches with the hostname. If not, it changes
+      # the hostname to the resolved IP address.
+      #
+      # The original hostname is used to validate the SSL, given in that scenario
+      # we'll be making the request to the IP address, instead of using the hostname.
+      def enforce_uri_hostname(addrs_info, uri, hostname, dns_rebind_protection)
+        address = addrs_info.first
+        ip_address = address&.ip_address
+
+        return [uri, nil] unless dns_rebind_protection && ip_address && ip_address != hostname
+
+        uri = uri.dup
+        uri.hostname = ip_address
+        [uri, hostname]
+      end
+
       def get_port(uri)
         uri.port || uri.default_port
       end

locale/gitlab.pot

@@ -3775,6 +3775,9 @@ msgstr ""
 msgid "Ends at (UTC)"
 msgstr ""
 
+msgid "Enforce DNS rebinding attack protection"
+msgstr ""
+
 msgid "Enter at least three characters to search"
 msgstr ""
 
@@ -8286,6 +8289,9 @@ msgstr ""
 msgid "Resolved by %{resolvedByName}"
 msgstr ""
 
+msgid "Resolves IP addresses once and uses them to submit requests"
+msgstr ""
+
 msgid "Response metrics (AWS ELB)"
 msgstr ""
 

spec/controllers/projects/ci/lints_controller_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe Projects::Ci::LintsController do
+  include StubRequests
+
   let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
 
@@ -70,7 +72,7 @@ describe Projects::Ci::LintsController do
 
     context 'with a valid gitlab-ci.yml' do
       before do
-        WebMock.stub_request(:get, remote_file_path).to_return(body: remote_file_content)
+        stub_full_request(remote_file_path).to_return(body: remote_file_content)
         project.add_developer(user)
 
         post :create, params: { namespace_id: project.namespace, project_id: project, content: content }

spec/features/admin/admin_settings_spec.rb

@@ -332,16 +332,19 @@ describe 'Admin updates settings' do
   end
 
   context 'Network page' do
-    it 'Enable outbound requests' do
+    it 'Changes Outbound requests settings' do
       visit network_admin_application_settings_path
 
       page.within('.as-outbound') do
         check 'Allow requests to the local network from hooks and services'
+        # Enabled by default
+        uncheck 'Enforce DNS rebinding attack protection'
         click_button 'Save changes'
       end
 
       expect(page).to have_content "Application settings saved successfully"
       expect(Gitlab::CurrentSettings.allow_local_requests_from_hooks_and_services).to be true
+      expect(Gitlab::CurrentSettings.dns_rebinding_protection_enabled).to be false
     end
   end
 

spec/lib/gitlab/ci/config/external/file/remote_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe Gitlab::Ci::Config::External::File::Remote do
+  include StubRequests
+
   let(:context) { described_class::Context.new(nil, '12345', nil, Set.new) }
   let(:params) { { remote: location } }
   let(:remote_file) { described_class.new(params, context) }
@@ -46,7 +48,7 @@ describe Gitlab::Ci::Config::External::File::Remote do
   describe "#valid?" do
     context 'when is a valid remote url' do
       before do
-        WebMock.stub_request(:get, location).to_return(body: remote_file_content)
+        stub_full_request(location).to_return(body: remote_file_content)
       end
 
       it 'returns true' do
@@ -92,7 +94,7 @@ describe Gitlab::Ci::Config::External::File::Remote do
   describe "#content" do
     context 'with a valid remote file' do
       before do
-        WebMock.stub_request(:get, location).to_return(body: remote_file_content)
+        stub_full_request(location).to_return(body: remote_file_content)
       end
 
       it 'returns the content of the file' do
@@ -114,7 +116,7 @@ describe Gitlab::Ci::Config::External::File::Remote do
       let(:location) { 'https://asdasdasdaj48ggerexample.com' }
 
       before do
-        WebMock.stub_request(:get, location).to_raise(SocketError.new('Some HTTP error'))
+        stub_full_request(location).to_raise(SocketError.new('Some HTTP error'))
       end
 
       it 'is nil' do
@@ -144,7 +146,7 @@ describe Gitlab::Ci::Config::External::File::Remote do
 
     context 'when timeout error has been raised' do
       before do
-        WebMock.stub_request(:get, location).to_timeout
+        stub_full_request(location).to_timeout
       end
 
       it 'returns error message about a timeout' do
@@ -154,7 +156,7 @@ describe Gitlab::Ci::Config::External::File::Remote do
 
     context 'when HTTP error has been raised' do
       before do
-        WebMock.stub_request(:get, location).to_raise(Gitlab::HTTP::Error)
+        stub_full_request(location).to_raise(Gitlab::HTTP::Error)
       end
 
       it 'returns error message about a HTTP error' do
@@ -164,7 +166,7 @@ describe Gitlab::Ci::Config::External::File::Remote do
 
     context 'when response has 404 status' do
       before do
-        WebMock.stub_request(:get, location).to_return(body: remote_file_content, status: 404)
+        stub_full_request(location).to_return(body: remote_file_content, status: 404)
       end
 
       it 'returns error message about a timeout' do

spec/lib/gitlab/ci/config/external/mapper_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe Gitlab::Ci::Config::External::Mapper do
+  include StubRequests
+
   set(:project) { create(:project, :repository) }
   set(:user) { create(:user) }
 
@@ -18,7 +20,7 @@ describe Gitlab::Ci::Config::External::Mapper do
   end
 
   before do
-    WebMock.stub_request(:get, remote_url).to_return(body: file_content)
+    stub_full_request(remote_url).to_return(body: file_content)
   end
 
   describe '#process' do

spec/lib/gitlab/ci/config/external/processor_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe Gitlab::Ci::Config::External::Processor do
+  include StubRequests
+
   set(:project) { create(:project, :repository) }
   set(:another_project) { create(:project, :repository) }
   set(:user) { create(:user) }
@@ -42,7 +44,7 @@ describe Gitlab::Ci::Config::External::Processor do
       let(:values) { { include: remote_file, image: 'ruby:2.2' } }
 
       before do
-        WebMock.stub_request(:get, remote_file).to_raise(SocketError.new('Some HTTP error'))
+        stub_full_request(remote_file).and_raise(SocketError.new('Some HTTP error'))
       end
 
       it 'raises an error' do
@@ -75,7 +77,7 @@ describe Gitlab::Ci::Config::External::Processor do
       end
 
       before do
-        WebMock.stub_request(:get, remote_file).to_return(body: external_file_content)
+        stub_full_request(remote_file).to_return(body: external_file_content)
       end
 
       it 'appends the file to the values' do
@@ -145,7 +147,7 @@ describe Gitlab::Ci::Config::External::Processor do
         allow_any_instance_of(Gitlab::Ci::Config::External::File::Local)
           .to receive(:fetch_local_content).and_return(local_file_content)
 
-        WebMock.stub_request(:get, remote_file).to_return(body: remote_file_content)
+        stub_full_request(remote_file).to_return(body: remote_file_content)
       end
 
       it 'appends the files to the values' do
@@ -191,7 +193,8 @@ describe Gitlab::Ci::Config::External::Processor do
       end
 
       it 'takes precedence' do
-        WebMock.stub_request(:get, remote_file).to_return(body: remote_file_content)
+        stub_full_request(remote_file).to_return(body: remote_file_content)
+
         expect(processor.perform[:image]).to eq('ruby:2.2')
       end
     end
@@ -231,7 +234,8 @@ describe Gitlab::Ci::Config::External::Processor do
           HEREDOC
         end
 
-        WebMock.stub_request(:get, 'http://my.domain.com/config.yml').to_return(body: 'remote_build: { script: echo Hello World }')
+        stub_full_request('http://my.domain.com/config.yml')
+          .to_return(body: 'remote_build: { script: echo Hello World }')
       end
 
       context 'when project is public' do
@@ -273,8 +277,10 @@ describe Gitlab::Ci::Config::External::Processor do
 
     context 'when config includes an external configuration file via SSL web request' do
       before do
-        stub_request(:get, 'https://sha256.badssl.com/fake.yml').to_return(body: 'image: ruby:2.6', status: 200)
-        stub_request(:get, 'https://self-signed.badssl.com/fake.yml')
+        stub_full_request('https://sha256.badssl.com/fake.yml', ip_address: '8.8.8.8')
+          .to_return(body: 'image: ruby:2.6', status: 200)
+
+        stub_full_request('https://self-signed.badssl.com/fake.yml', ip_address: '8.8.8.9')
           .to_raise(OpenSSL::SSL::SSLError.new('SSL_connect returned=1 errno=0 state=error: certificate verify failed (self signed certificate)'))
       end
 

spec/lib/gitlab/ci/config_spec.rb

 require 'spec_helper'
 
 describe Gitlab::Ci::Config do
+  include StubRequests
+
   set(:user) { create(:user) }
 
   let(:config) do
@@ -216,8 +218,7 @@ describe Gitlab::Ci::Config do
     end
 
     before do
-      WebMock.stub_request(:get, remote_location)
-        .to_return(body: remote_file_content)
+      stub_full_request(remote_location).to_return(body: remote_file_content)
 
       allow(project.repository)
         .to receive(:blob_data_at).and_return(local_file_content)

spec/lib/gitlab/ci/yaml_processor_spec.rb

@@ -3,6 +3,8 @@ require 'spec_helper'
 module Gitlab
   module Ci
     describe YamlProcessor do
+      include StubRequests
+
       subject { described_class.new(config, user: nil) }
 
       describe '#build_attributes' do
@@ -648,7 +650,7 @@ module Gitlab
             end
 
             before do
-              WebMock.stub_request(:get, 'https://gitlab.com/awesome-project/raw/master/.before-script-template.yml')
+              stub_full_request('https://gitlab.com/awesome-project/raw/master/.before-script-template.yml')
                 .to_return(
                   status: 200,
                   headers: { 'Content-Type' => 'application/json' },

spec/lib/gitlab/http_connection_adapter_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::HTTPConnectionAdapter do
+  describe '#connection' do
+    context 'when local requests are not allowed' do
+      it 'sets up the connection' do
+        uri = URI('https://example.org')
+
+        connection = described_class.new(uri).connection
+
+        expect(connection).to be_a(Net::HTTP)
+        expect(connection.address).to eq('93.184.216.34')
+        expect(connection.hostname_override).to eq('example.org')
+        expect(connection.addr_port).to eq('example.org')
+        expect(connection.port).to eq(443)
+      end
+
+      it 'raises error when it is a request to local address' do
+        uri = URI('http://172.16.0.0/12')
+
+        expect { described_class.new(uri).connection }
+          .to raise_error(Gitlab::HTTP::BlockedUrlError,
+                          "URL 'http://172.16.0.0/12' is blocked: Requests to the local network are not allowed")
+      end
+
+      it 'raises error when it is a request to localhost address' do
+        uri = URI('http://127.0.0.1')
+
+        expect { described_class.new(uri).connection }
+          .to raise_error(Gitlab::HTTP::BlockedUrlError,
+                          "URL 'http://127.0.0.1' is blocked: Requests to localhost are not allowed")
+      end
+
+      context 'when port different from URL scheme is used' do
+        it 'sets up the addr_port accordingly' do
+          uri = URI('https://example.org:8080')
+
+          connection = described_class.new(uri).connection
+
+          expect(connection.address).to eq('93.184.216.34')
+          expect(connection.hostname_override).to eq('example.org')
+          expect(connection.addr_port).to eq('example.org:8080')
+          expect(connection.port).to eq(8080)
+        end
+      end
+    end
+
+    context 'when DNS rebinding protection is disabled' do
+      it 'sets up the connection' do
+        stub_application_setting(dns_rebinding_protection_enabled: false)
+
+        uri = URI('https://example.org')
+
+        connection = described_class.new(uri).connection
+
+        expect(connection).to be_a(Net::HTTP)
+        expect(connection.address).to eq('example.org')
+        expect(connection.hostname_override).to eq(nil)
+        expect(connection.addr_port).to eq('example.org')
+        expect(connection.port).to eq(443)
+      end
+    end
+
+    context 'when http(s) environment variable is set' do
+      it 'sets up the connection' do
+        stub_env('https_proxy' => 'https://my.proxy')
+
+        uri = URI('https://example.org')
+
+        connection = described_class.new(uri).connection
+
+        expect(connection).to be_a(Net::HTTP)
+        expect(connection.address).to eq('example.org')
+        expect(connection.hostname_override).to eq(nil)
+        expect(connection.addr_port).to eq('example.org')
+        expect(connection.port).to eq(443)
+      end
+    end
+
+    context 'when local requests are allowed' do
+      it 'sets up the connection' do
+        uri = URI('https://example.org')
+
+        connection = described_class.new(uri, allow_local_requests: true).connection
+
+        expect(connection).to be_a(Net::HTTP)
+        expect(connection.address).to eq('93.184.216.34')
+        expect(connection.hostname_override).to eq('example.org')
+        expect(connection.addr_port).to eq('example.org')
+        expect(connection.port).to eq(443)
+      end
+
+      it 'sets up the connection when it is a local network' do
+        uri = URI('http://172.16.0.0/12')
+
+        connection = described_class.new(uri, allow_local_requests: true).connection
+
+        expect(connection).to be_a(Net::HTTP)
+        expect(connection.address).to eq('172.16.0.0')
+        expect(connection.hostname_override).to be(nil)
+        expect(connection.addr_port).to eq('172.16.0.0')
+        expect(connection.port).to eq(80)
+      end
+
+      it 'sets up the connection when it is localhost' do
+        uri = URI('http://127.0.0.1')
+
+        connection = described_class.new(uri, allow_local_requests: true).connection
+
+        expect(connection).to be_a(Net::HTTP)
+        expect(connection.address).to eq('127.0.0.1')
+        expect(connection.hostname_override).to be(nil)
+        expect(connection.addr_port).to eq('127.0.0.1')
+        expect(connection.port).to eq(80)
+      end
+    end
+  end
+end

spec/lib/gitlab/http_spec.rb

 require 'spec_helper'
 
 describe Gitlab::HTTP do
+  include StubRequests
+
+  context 'when allow_local_requests' do
+    it 'sends the request to the correct URI' do
+      stub_full_request('https://example.org:8080', ip_address: '8.8.8.8').to_return(status: 200)
+
+      described_class.get('https://example.org:8080', allow_local_requests: false)
+
+      expect(WebMock).to have_requested(:get, 'https://8.8.8.8:8080').once
+    end
+  end
+
+  context 'when not allow_local_requests' do
+    it 'sends the request to the correct URI' do
+      stub_full_request('https://example.org:8080')
+
+      described_class.get('https://example.org:8080', allow_local_requests: true)
+
+      expect(WebMock).to have_requested(:get, 'https://8.8.8.9:8080').once
+    end
+  end
+
   describe 'allow_local_requests_from_hooks_and_services is' do
     before do
       WebMock.stub_request(:get, /.*/).to_return(status: 200, body: 'Success')
@@ -21,6 +43,8 @@ describe Gitlab::HTTP do
 
       context 'if allow_local_requests set to true' do
         it 'override the global value and allow requests to localhost or private network' do
+          stub_full_request('http://localhost:3003')
+
           expect { described_class.get('http://localhost:3003', allow_local_requests: true) }.not_to raise_error
         end
       end
@@ -32,6 +56,8 @@ describe Gitlab::HTTP do
       end
 
       it 'allow requests to localhost' do
+        stub_full_request('http://localhost:3003')
+
         expect { described_class.get('http://localhost:3003') }.not_to raise_error
       end
 
@@ -49,7 +75,7 @@ describe Gitlab::HTTP do
 
   describe 'handle redirect loops' do
     before do
-      WebMock.stub_request(:any, "http://example.org").to_raise(HTTParty::RedirectionTooDeep.new("Redirection Too Deep"))
+      stub_full_request("http://example.org", method: :any).to_raise(HTTParty::RedirectionTooDeep.new("Redirection Too Deep"))
     end
 
     it 'handles GET requests' do

spec/lib/gitlab/import_export/after_export_strategies/web_upload_strategy_spec.rb

 require 'spec_helper'
 
 describe Gitlab::ImportExport::AfterExportStrategies::WebUploadStrategy do
+  include StubRequests
+
   let(:example_url) { 'http://www.example.com' }
   let(:strategy) { subject.new(url: example_url, http_method: 'post') }
   let!(:project) { create(:project, :with_export) }
@@ -35,7 +37,7 @@ describe Gitlab::ImportExport::AfterExportStrategies::WebUploadStrategy do
 
     context 'when upload fails' do
       it 'stores the export error' do
-        stub_request(:post, example_url).to_return(status: [404, 'Page not found'])
+        stub_full_request(example_url, method: :post).to_return(status: [404, 'Page not found'])
 
         strategy.execute(user, project)
 

spec/lib/gitlab/url_blocker_spec.rb

@@ -2,6 +2,87 @@
 require 'spec_helper'
 
 describe Gitlab::UrlBlocker do
+  describe '#validate!' do
+    context 'when URI is nil' do
+      let(:import_url) { nil }
+
+      it 'returns no URI and hostname' do
+        uri, hostname = described_class.validate!(import_url)
+
+        expect(uri).to be(nil)
+        expect(hostname).to be(nil)
+      end
+    end
+
+    context 'when URI is internal' do
+      let(:import_url) { 'http://localhost' }
+
+      it 'returns URI and no hostname' do
+        uri, hostname = described_class.validate!(import_url)
+
+        expect(uri).to eq(Addressable::URI.parse('http://[::1]'))
+        expect(hostname).to eq('localhost')
+      end
+    end
+
+    context 'when the URL hostname is a domain' do
+      let(:import_url) { 'https://example.org' }
+
+      it 'returns URI and hostname' do
+        uri, hostname = described_class.validate!(import_url)
+
+        expect(uri).to eq(Addressable::URI.parse('https://93.184.216.34'))
+        expect(hostname).to eq('example.org')
+      end
+    end
+
+    context 'when the URL hostname is an IP address' do
+      let(:import_url) { 'https://93.184.216.34' }
+
+      it 'returns URI and no hostname' do
+        uri, hostname = described_class.validate!(import_url)
+
+        expect(uri).to eq(Addressable::URI.parse('https://93.184.216.34'))
+        expect(hostname).to be(nil)
+      end
+    end
+
+    context 'disabled DNS rebinding protection' do
+      context 'when URI is internal' do
+        let(:import_url) { 'http://localhost' }
+
+        it 'returns URI and no hostname' do
+          uri, hostname = described_class.validate!(import_url, dns_rebind_protection: false)
+
+          expect(uri).to eq(Addressable::URI.parse('http://localhost'))
+          expect(hostname).to be(nil)
+        end
+      end
+
+      context 'when the URL hostname is a domain' do
+        let(:import_url) { 'https://example.org' }
+
+        it 'returns URI and no hostname' do
+          uri, hostname = described_class.validate!(import_url, dns_rebind_protection: false)
+
+          expect(uri).to eq(Addressable::URI.parse('https://example.org'))
+          expect(hostname).to eq(nil)
+        end
+      end
+
+      context 'when the URL hostname is an IP address' do
+        let(:import_url) { 'https://93.184.216.34' }
+
+        it 'returns URI and no hostname' do
+          uri, hostname = described_class.validate!(import_url, dns_rebind_protection: false)
+
+          expect(uri).to eq(Addressable::URI.parse('https://93.184.216.34'))
+          expect(hostname).to be(nil)
+        end
+      end
+    end
+  end
+
   describe '#blocked_url?' do
     let(:ports) { Project::VALID_IMPORT_PORTS }
 
@@ -208,7 +289,7 @@ describe Gitlab::UrlBlocker do
       end
 
       def stub_domain_resolv(domain, ip)
-        address = double(ip_address: ip, ipv4_private?: true, ipv6_link_local?: false, ipv4_loopback?: false, ipv6_loopback?: false)
+        address = double(ip_address: ip, ipv4_private?: true, ipv6_link_local?: false, ipv4_loopback?: false, ipv6_loopback?: false, ipv4?: false)
         allow(Addrinfo).to receive(:getaddrinfo).with(domain, any_args).and_return([address])
         allow(address).to receive(:ipv6_v4mapped?).and_return(false)
       end

spec/lib/gitlab_spec.rb

@@ -109,4 +109,34 @@ describe Gitlab do
       expect(described_class.ee?).to eq(false)
     end
   end
+
+  describe '.http_proxy_env?' do
+    it 'returns true when lower case https' do
+      stub_env('https_proxy', 'https://my.proxy')
+
+      expect(described_class.http_proxy_env?).to eq(true)
+    end
+
+    it 'returns true when upper case https' do
+      stub_env('HTTPS_PROXY', 'https://my.proxy')
+
+      expect(described_class.http_proxy_env?).to eq(true)
+    end
+
+    it 'returns true when lower case http' do
+      stub_env('http_proxy', 'http://my.proxy')
+
+      expect(described_class.http_proxy_env?).to eq(true)
+    end
+
+    it 'returns true when upper case http' do
+      stub_env('HTTP_PROXY', 'http://my.proxy')
+
+      expect(described_class.http_proxy_env?).to eq(true)
+    end
+
+    it 'returns false when not set' do
+      expect(described_class.http_proxy_env?).to eq(false)
+    end
+  end
 end

spec/lib/mattermost/session_spec.rb

@@ -2,6 +2,7 @@ require 'spec_helper'
 
 describe Mattermost::Session, type: :request do
   include ExclusiveLeaseHelpers
+  include StubRequests
 
   let(:user) { create(:user) }
 
@@ -24,7 +25,7 @@ describe Mattermost::Session, type: :request do
     let(:location) { 'http://location.tld' }
     let(:cookie_header) {'MMOAUTH=taskik8az7rq8k6rkpuas7htia; Path=/;'}
     let!(:stub) do
-      WebMock.stub_request(:get, "#{mattermost_url}/oauth/gitlab/login")
+      stub_full_request("#{mattermost_url}/oauth/gitlab/login")
         .to_return(headers: { 'location' => location, 'Set-Cookie' => cookie_header }, status: 302)
     end
 
@@ -63,7 +64,7 @@ describe Mattermost::Session, type: :request do
         end
 
         before do
-          WebMock.stub_request(:get, "#{mattermost_url}/signup/gitlab/complete")
+          stub_full_request("#{mattermost_url}/signup/gitlab/complete")
             .with(query: hash_including({ 'state' => state }))
             .to_return do |request|
               post "/oauth/token",
@@ -80,7 +81,7 @@ describe Mattermost::Session, type: :request do
               end
             end
 
-          WebMock.stub_request(:post, "#{mattermost_url}/api/v4/users/logout")
+          stub_full_request("#{mattermost_url}/api/v4/users/logout", method: :post)
             .to_return(headers: { Authorization: 'token thisworksnow' }, status: 200)
         end
 

spec/models/project_services/assembla_service_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe AssemblaService do
+  include StubRequests
+
   describe "Associations" do
     it { is_expected.to belong_to :project }
     it { is_expected.to have_one :service_hook }
@@ -23,12 +25,12 @@ describe AssemblaService do
       )
       @sample_data = Gitlab::DataBuilder::Push.build_sample(project, user)
       @api_url = 'https://atlas.assembla.com/spaces/project_name/github_tool?secret_key=verySecret'
-      WebMock.stub_request(:post, @api_url)
+      stub_full_request(@api_url, method: :post)
     end
 
     it "calls Assembla API" do
       @assembla_service.execute(@sample_data)
-      expect(WebMock).to have_requested(:post, @api_url).with(
+      expect(WebMock).to have_requested(:post, stubbed_hostname(@api_url)).with(
         body: /#{@sample_data[:before]}.*#{@sample_data[:after]}.*#{project.path}/
       ).once
     end

spec/models/project_services/bamboo_service_spec.rb

@@ -4,6 +4,7 @@ require 'spec_helper'
 
 describe BambooService, :use_clean_rails_memory_store_caching do
   include ReactiveCachingHelpers
+  include StubRequests
 
   let(:bamboo_url) { 'http://gitlab.com/bamboo' }
 
@@ -257,7 +258,7 @@ describe BambooService, :use_clean_rails_memory_store_caching do
   end
 
   def stub_bamboo_request(url, status, body)
-    WebMock.stub_request(:get, url).to_return(
+    stub_full_request(url).to_return(
       status: status,
       headers: { 'Content-Type' => 'application/json' },
       body: body

spec/models/project_services/buildkite_service_spec.rb

@@ -4,6 +4,7 @@ require 'spec_helper'
 
 describe BuildkiteService, :use_clean_rails_memory_store_caching do
   include ReactiveCachingHelpers
+  include StubRequests
 
   let(:project) { create(:project) }
 
@@ -110,10 +111,9 @@ describe BuildkiteService, :use_clean_rails_memory_store_caching do
     body ||= %q({"status":"success"})
     buildkite_full_url = 'https://gitlab.buildkite.com/status/secret-sauce-status-token.json?commit=123'
 
-    WebMock.stub_request(:get, buildkite_full_url).to_return(
-      status: status,
-      headers: { 'Content-Type' => 'application/json' },
-      body: body
-    )
+    stub_full_request(buildkite_full_url)
+      .to_return(status: status,
+                 headers: { 'Content-Type' => 'application/json' },
+                 body: body)
   end
 end

spec/models/project_services/campfire_service_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe CampfireService do
+  include StubRequests
+
   describe 'Associations' do
     it { is_expected.to belong_to :project }
     it { is_expected.to have_one :service_hook }
@@ -49,39 +51,37 @@ describe CampfireService do
     it "calls Campfire API to get a list of rooms and speak in a room" do
       # make sure a valid list of rooms is returned
       body = File.read(Rails.root + 'spec/fixtures/project_services/campfire/rooms.json')
-      WebMock.stub_request(:get, @rooms_url).with(basic_auth: @auth).to_return(
+
+      stub_full_request(@rooms_url).with(basic_auth: @auth).to_return(
         body: body,
         status: 200,
         headers: @headers
       )
+
       # stub the speak request with the room id found in the previous request's response
       speak_url = 'https://project-name.campfirenow.com/room/123/speak.json'
-      WebMock.stub_request(:post, speak_url).with(basic_auth: @auth)
+      stub_full_request(speak_url, method: :post).with(basic_auth: @auth)
 
       @campfire_service.execute(@sample_data)
 
-      expect(WebMock).to have_requested(:get, @rooms_url).once
-      expect(WebMock).to have_requested(:post, speak_url).with(
-        body: /#{project.path}.*#{@sample_data[:before]}.*#{@sample_data[:after]}/
-      ).once
+      expect(WebMock).to have_requested(:get, stubbed_hostname(@rooms_url)).once
+      expect(WebMock).to have_requested(:post, stubbed_hostname(speak_url))
+                           .with(body: /#{project.path}.*#{@sample_data[:before]}.*#{@sample_data[:after]}/).once
     end
 
     it "calls Campfire API to get a list of rooms but shouldn't speak in a room" do
       # return a list of rooms that do not contain a room named 'test-room'
       body = File.read(Rails.root + 'spec/fixtures/project_services/campfire/rooms2.json')
-      WebMock.stub_request(:get, @rooms_url).with(basic_auth: @auth).to_return(
+      stub_full_request(@rooms_url).with(basic_auth: @auth).to_return(
         body: body,
         status: 200,
         headers: @headers
       )
-      # we want to make sure no request is sent to the /speak endpoint, here is a basic
-      # regexp that matches this endpoint
-      speak_url = 'https://verySecret:X@project-name.campfirenow.com/room/.*/speak.json'
 
       @campfire_service.execute(@sample_data)
 
-      expect(WebMock).to have_requested(:get, @rooms_url).once
-      expect(WebMock).not_to have_requested(:post, /#{speak_url}/)
+      expect(WebMock).to have_requested(:get, 'https://8.8.8.9/rooms.json').once
+      expect(WebMock).not_to have_requested(:post, '*/room/.*/speak.json')
     end
   end
 end

spec/models/project_services/pivotaltracker_service_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe PivotaltrackerService do
+  include StubRequests
+
   describe 'Associations' do
     it { is_expected.to belong_to :project }
     it { is_expected.to have_one :service_hook }
@@ -53,12 +55,12 @@ describe PivotaltrackerService do
     end
 
     before do
-      WebMock.stub_request(:post, url)
+      stub_full_request(url, method: :post)
     end
 
     it 'posts correct message' do
       service.execute(push_data)
-      expect(WebMock).to have_requested(:post, url).with(
+      expect(WebMock).to have_requested(:post, stubbed_hostname(url)).with(
         body: {
           'source_commit' => {
             'commit_id' => '21c12ea',
@@ -85,14 +87,14 @@ describe PivotaltrackerService do
         service.execute(push_data(branch: 'master'))
         service.execute(push_data(branch: 'v10'))
 
-        expect(WebMock).to have_requested(:post, url).twice
+        expect(WebMock).to have_requested(:post, stubbed_hostname(url)).twice
       end
 
       it 'does not post message if branch is not in the list' do
         service.execute(push_data(branch: 'mas'))
         service.execute(push_data(branch: 'v11'))
 
-        expect(WebMock).not_to have_requested(:post, url)
+        expect(WebMock).not_to have_requested(:post, stubbed_hostname(url))
       end
     end
   end

spec/models/project_services/pushover_service_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe PushoverService do
+  include StubRequests
+
   describe 'Associations' do
     it { is_expected.to belong_to :project }
     it { is_expected.to have_one :service_hook }
@@ -57,13 +59,13 @@ describe PushoverService do
         sound: sound
       )
 
-      WebMock.stub_request(:post, api_url)
+      stub_full_request(api_url, method: :post, ip_address: '8.8.8.8')
     end
 
     it 'calls Pushover API' do
       pushover.execute(sample_data)
 
-      expect(WebMock).to have_requested(:post, api_url).once
+      expect(WebMock).to have_requested(:post, 'https://8.8.8.8/1/messages.json').once
     end
   end
 end

spec/models/project_services/teamcity_service_spec.rb

@@ -4,6 +4,7 @@ require 'spec_helper'
 
 describe TeamcityService, :use_clean_rails_memory_store_caching do
   include ReactiveCachingHelpers
+  include StubRequests
 
   let(:teamcity_url) { 'http://gitlab.com/teamcity' }
 
@@ -212,7 +213,7 @@ describe TeamcityService, :use_clean_rails_memory_store_caching do
 
     body ||= %Q({"build":{"status":"#{build_status}","id":"666"}})
 
-    WebMock.stub_request(:get, teamcity_full_url).with(basic_auth: auth).to_return(
+    stub_full_request(teamcity_full_url).with(basic_auth: auth).to_return(
       status: status,
       headers: { 'Content-Type' => 'application/json' },
       body: body

spec/requests/api/system_hooks_spec.rb

 require 'spec_helper'
 
 describe API::SystemHooks do
+  include StubRequests
+
   let(:user) { create(:user) }
   let(:admin) { create(:admin) }
   let!(:hook) { create(:system_hook, url: "http://example.com") }
 
   before do
-    stub_request(:post, hook.url)
+    stub_full_request(hook.url, method: :post)
   end
 
   describe "GET /hooks" do
@@ -68,6 +70,8 @@ describe API::SystemHooks do
     end
 
     it 'sets default values for events' do
+      stub_full_request('http://mep.mep', method: :post)
+
       post api('/hooks', admin), params: { url: 'http://mep.mep' }
 
       expect(response).to have_gitlab_http_status(201)
@@ -78,6 +82,8 @@ describe API::SystemHooks do
     end
 
     it 'sets explicit values for events' do
+      stub_full_request('http://mep.mep', method: :post)
+
       post api('/hooks', admin),
         params: {
           url: 'http://mep.mep',

spec/services/projects/lfs_pointers/lfs_download_service_spec.rb

@@ -2,6 +2,8 @@
 require 'spec_helper'
 
 describe Projects::LfsPointers::LfsDownloadService do
+  include StubRequests
+
   let(:project) { create(:project) }
   let(:lfs_content) { SecureRandom.random_bytes(10) }
   let(:oid) { Digest::SHA256.hexdigest(lfs_content) }
@@ -62,7 +64,7 @@ describe Projects::LfsPointers::LfsDownloadService do
   describe '#execute' do
     context 'when file download succeeds' do
       before do
-        WebMock.stub_request(:get, download_link).to_return(body: lfs_content)
+        stub_full_request(download_link).to_return(body: lfs_content)
       end
 
       it_behaves_like 'lfs object is created'
@@ -104,7 +106,7 @@ describe Projects::LfsPointers::LfsDownloadService do
       let(:size) { 1 }
 
       before do
-        WebMock.stub_request(:get, download_link).to_return(body: lfs_content)
+        stub_full_request(download_link).to_return(body: lfs_content)
       end
 
       it_behaves_like 'no lfs object is created'
@@ -118,7 +120,7 @@ describe Projects::LfsPointers::LfsDownloadService do
 
     context 'when downloaded lfs file has a different oid' do
       before do
-        WebMock.stub_request(:get, download_link).to_return(body: lfs_content)
+        stub_full_request(download_link).to_return(body: lfs_content)
         allow_any_instance_of(Digest::SHA256).to receive(:hexdigest).and_return('foobar')
       end
 
@@ -136,7 +138,7 @@ describe Projects::LfsPointers::LfsDownloadService do
       let(:lfs_object) { LfsDownloadObject.new(oid: oid, size: size, link: download_link_with_credentials) }
 
       before do
-        WebMock.stub_request(:get, download_link).with(headers: { 'Authorization' => 'Basic dXNlcjpwYXNzd29yZA==' }).to_return(body: lfs_content)
+        stub_full_request(download_link).with(headers: { 'Authorization' => 'Basic dXNlcjpwYXNzd29yZA==' }).to_return(body: lfs_content)
       end
 
       it 'the request adds authorization headers' do
@@ -149,7 +151,7 @@ describe Projects::LfsPointers::LfsDownloadService do
       let(:local_request_setting) { true }
 
       before do
-        WebMock.stub_request(:get, download_link).to_return(body: lfs_content)
+        stub_full_request(download_link, ip_address: '192.168.2.120').to_return(body: lfs_content)
       end
 
       it_behaves_like 'lfs object is created'
@@ -173,7 +175,8 @@ describe Projects::LfsPointers::LfsDownloadService do
 
         with_them do
           before do
-            WebMock.stub_request(:get, download_link).to_return(status: 301, headers: { 'Location' => redirect_link })
+            stub_full_request(download_link, ip_address: '192.168.2.120')
+              .to_return(status: 301, headers: { 'Location' => redirect_link })
           end
 
           it_behaves_like 'no lfs object is created'
@@ -184,8 +187,8 @@ describe Projects::LfsPointers::LfsDownloadService do
         let(:redirect_link) { "http://example.com/"}
 
         before do
-          WebMock.stub_request(:get, download_link).to_return(status: 301, headers: { 'Location' => redirect_link })
-          WebMock.stub_request(:get, redirect_link).to_return(body: lfs_content)
+          stub_full_request(download_link).to_return(status: 301, headers: { 'Location' => redirect_link })
+          stub_full_request(redirect_link).to_return(body: lfs_content)
         end
 
         it_behaves_like 'lfs object is created'

spec/services/submit_usage_ping_service_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe SubmitUsagePingService do
+  include StubRequests
+
   context 'when usage ping is disabled' do
     before do
       stub_application_setting(usage_ping_enabled: false)
@@ -99,7 +101,7 @@ describe SubmitUsagePingService do
   end
 
   def stub_response(body)
-    stub_request(:post, 'https://version.gitlab.com/usage_data')
+    stub_full_request('https://version.gitlab.com/usage_data', method: :post)
       .to_return(
         headers: { 'Content-Type' => 'application/json' },
         body: body.to_json

spec/services/web_hook_service_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe WebHookService do
+  include StubRequests
+
   let(:project) { create(:project) }
   let(:project_hook) { create(:project_hook) }
   let(:headers) do
@@ -67,11 +69,11 @@ describe WebHookService do
       let(:project_hook) { create(:project_hook, url: 'https://demo:demo@example.org/') }
 
       it 'uses the credentials' do
-        WebMock.stub_request(:post, url)
+        stub_full_request(url, method: :post)
 
         service_instance.execute
 
-        expect(WebMock).to have_requested(:post, url).with(
+        expect(WebMock).to have_requested(:post, stubbed_hostname(url)).with(
           headers: headers.merge('Authorization' => 'Basic ZGVtbzpkZW1v')
         ).once
       end
@@ -82,11 +84,11 @@ describe WebHookService do
       let(:project_hook) { create(:project_hook, url: 'https://demo@example.org/') }
 
       it 'uses the credentials anyways' do
-        WebMock.stub_request(:post, url)
+        stub_full_request(url, method: :post)
 
         service_instance.execute
 
-        expect(WebMock).to have_requested(:post, url).with(
+        expect(WebMock).to have_requested(:post, stubbed_hostname(url)).with(
           headers: headers.merge('Authorization' => 'Basic ZGVtbzo=')
         ).once
       end

spec/support/helpers/stub_requests.rb

+module StubRequests
+  IP_ADDRESS_STUB = '8.8.8.9'.freeze
+
+  # Fully stubs a request using WebMock class. This class also
+  # stubs the IP address the URL is translated to (DNS lookup).
+  #
+  # It expects the final request to go to the `ip_address` instead the given url.
+  # That's primarily a DNS rebind attack prevention of Gitlab::HTTP
+  # (see: Gitlab::UrlBlocker).
+  #
+  def stub_full_request(url, ip_address: IP_ADDRESS_STUB, port: 80, method: :get)
+    stub_dns(url, ip_address: ip_address, port: port)
+
+    url = stubbed_hostname(url, hostname: ip_address)
+    WebMock.stub_request(method, url)
+  end
+
+  def stub_dns(url, ip_address:, port: 80)
+    url = parse_url(url)
+    socket = Socket.sockaddr_in(port, ip_address)
+    addr = Addrinfo.new(socket)
+
+    # See Gitlab::UrlBlocker
+    allow(Addrinfo).to receive(:getaddrinfo)
+                         .with(url.hostname, url.port, nil, :STREAM)
+                         .and_return([addr])
+  end
+
+  def stubbed_hostname(url, hostname: IP_ADDRESS_STUB)
+    url = parse_url(url)
+    url.hostname = hostname
+    url.to_s
+  end
+
+  private
+
+  def parse_url(url)
+    url.is_a?(URI) ? url : URI(url)
+  end
+end