Override hostname when connecting via Kubeclient

Kubeclient uses rest-client. We hack into to access the net/http object
so that we can patch to connect to the resolved IP + set
hostname_override.

Add specs for discord. The discord integration also uses rest-client, so
since we patched rest-client, spec that the DNS rebinding protection
works

1 files changed, 147 insertions, 0 deletions

diff --git a/spec/initializers/rest-client-hostname_override_spec.rb b/spec/initializers/rest-client-hostname_override_spec.rb
new file mode 100644
index 00000000000..1ff82342fb5
--- /dev/null
+++ b/spec/initializers/rest-client-hostname_override_spec.rb
@@ -0,0 +1,147 @@
+require 'spec_helper'
+
+describe 'rest-client dns rebinding protection' do
+  include StubRequests
+
+  context 'when local requests are not allowed' do
+    it 'allows an external request with http' do
+      request_stub = stub_full_request('http://example.com', ip_address: '93.184.216.34')
+
+      RestClient.get('http://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'allows an external request with https' do
+      request_stub = stub_full_request('https://example.com', ip_address: '93.184.216.34')
+
+      RestClient.get('https://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'raises error when it is a request that resolves to a local address' do
+      stub_full_request('https://example.com', ip_address: '172.16.0.0')
+
+      expect { RestClient.get('https://example.com') }
+        .to raise_error(ArgumentError,
+                        "URL 'https://example.com' is blocked: Requests to the local network are not allowed")
+    end
+
+    it 'raises error when it is a request that resolves to a localhost address' do
+      stub_full_request('https://example.com', ip_address: '127.0.0.1')
+
+      expect { RestClient.get('https://example.com') }
+        .to raise_error(ArgumentError,
+                        "URL 'https://example.com' is blocked: Requests to localhost are not allowed")
+    end
+
+    it 'raises error when it is a request to local address' do
+      expect { RestClient.get('http://172.16.0.0') }
+        .to raise_error(ArgumentError,
+                        "URL 'http://172.16.0.0' is blocked: Requests to the local network are not allowed")
+    end
+
+    it 'raises error when it is a request to localhost address' do
+      expect { RestClient.get('http://127.0.0.1') }
+        .to raise_error(ArgumentError,
+                        "URL 'http://127.0.0.1' is blocked: Requests to localhost are not allowed")
+    end
+  end
+
+  context 'when port different from URL scheme is used' do
+    it 'allows the request' do
+      request_stub = stub_full_request('https://example.com:8080', ip_address: '93.184.216.34')
+
+      RestClient.get('https://example.com:8080/')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'raises error when it is a request to local address' do
+      expect { RestClient.get('https://172.16.0.0:8080') }
+        .to raise_error(ArgumentError,
+                        "URL 'https://172.16.0.0:8080' is blocked: Requests to the local network are not allowed")
+    end
+
+    it 'raises error when it is a request to localhost address' do
+      expect { RestClient.get('https://127.0.0.1:8080') }
+        .to raise_error(ArgumentError,
+                        "URL 'https://127.0.0.1:8080' is blocked: Requests to localhost are not allowed")
+    end
+  end
+
+  context 'when DNS rebinding protection is disabled' do
+    before do
+      stub_application_setting(dns_rebinding_protection_enabled: false)
+    end
+
+    it 'allows the request' do
+      request_stub = stub_request(:get, 'https://example.com')
+
+      RestClient.get('https://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+  end
+
+  context 'when http(s) proxy environment variable is set' do
+    before do
+      stub_env('https_proxy' => 'https://my.proxy')
+    end
+
+    it 'allows the request' do
+      request_stub = stub_request(:get, 'https://example.com')
+
+      RestClient.get('https://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+  end
+
+  context 'when local requests are allowed' do
+    before do
+      stub_application_setting(allow_local_requests_from_hooks_and_services: true)
+    end
+
+    it 'allows an external request' do
+      request_stub = stub_full_request('https://example.com', ip_address: '93.184.216.34')
+
+      RestClient.get('https://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'allows an external request that resolves to a local address' do
+      request_stub = stub_full_request('https://example.com', ip_address: '172.16.0.0')
+
+      RestClient.get('https://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'allows an external request that resolves to a localhost address' do
+      request_stub = stub_full_request('https://example.com', ip_address: '127.0.0.1')
+
+      RestClient.get('https://example.com/')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'allows a local address request' do
+      request_stub = stub_request(:get, 'http://172.16.0.0')
+
+      RestClient.get('http://172.16.0.0')
+
+      expect(request_stub).to have_been_requested
+    end
+
+    it 'allows a localhost address request' do
+      request_stub = stub_request(:get, 'http://127.0.0.1')
+
+      RestClient.get('http://127.0.0.1')
+
+      expect(request_stub).to have_been_requested
+    end
+  end
+end