Protect Gitlab::HTTP against DNS rebinding attack

Gitlab::HTTP now resolves the hostname only once, verifies the IP is not
blocked, and then uses the same IP to perform the actual request, while
passing the original hostname in the `Host` header and SSL SNI field.

1 files changed, 88 insertions, 0 deletions

diff --git a/spec/lib/gitlab/http_connection_adapter_spec.rb b/spec/lib/gitlab/http_connection_adapter_spec.rb
new file mode 100644
index 00000000000..af033be8e5b
--- /dev/null
+++ b/spec/lib/gitlab/http_connection_adapter_spec.rb
@@ -0,0 +1,88 @@
+# 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 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