Add CA bundle version and pinning status to the user agent string

lib/duo_api/api_client.rb

@@ -17,6 +17,9 @@ class DuoApi
 
   VERSION = Gem.loaded_specs['duo_api'] ? Gem.loaded_specs['duo_api'].version : '0.0.0'
 
+  # Version of the bundled CA certificate collection
+  CA_BUNDLE_VERSION = '1.0'
+
   # Constants for handling rate limit backoff
   MAX_BACKOFF_WAIT_SECS = 32
   INITIAL_BACKOFF_WAIT_SECS = 1
@@ -78,7 +81,7 @@ def request(method, path, params = {}, additional_headers = nil)
     request = Net::HTTP.const_get(method.capitalize).new(uri.to_s)
     request.basic_auth(@ikey, signed)
     request['Date'] = current_date
-    request['User-Agent'] = "duo_api_ruby/#{VERSION}"
+    request['User-Agent'] = user_agent
 
     # Set Content-Type and request body for JSON requests
     if params_go_in_body
@@ -106,6 +109,13 @@ def request(method, path, params = {}, additional_headers = nil)
 
   private
 
+  # Build the User-Agent string, including the CA bundle version and the
+  # current CA pinning state.
+  def user_agent
+    ca_pinning_state = @ca_pinning_disabled ? 'disable' : 'enable'
+    "duo_api_ruby/#{VERSION} ca_bundle/#{CA_BUNDLE_VERSION} (ca_pinning=#{ca_pinning_state})"
+  end
+
   # Encode a key-value pair for a URL
   def encode_key_val(key, val)
     key = ERB::Util.url_encode(key.to_s)

test/test_disable_ca_pinning.rb

@@ -65,3 +65,51 @@ def test_unpinned_client_does_not_pass_ca_file_to_http
     @client_unpinned.request('GET', '/foo/bar')
   end
 end
+
+class TestUserAgent < BaseTestCase
+  def test_user_agent_includes_ca_bundle_version
+    assert_include(@client.send(:user_agent), "ca_bundle/#{DuoApi::CA_BUNDLE_VERSION}")
+  end
+
+  def test_user_agent_pinning_enabled_by_default
+    client = DuoApi.new(IKEY, SKEY, HOST)
+    assert_equal(
+      "duo_api_ruby/#{DuoApi::VERSION} ca_bundle/#{DuoApi::CA_BUNDLE_VERSION} (ca_pinning=enable)",
+      client.send(:user_agent)
+    )
+  end
+
+  def test_user_agent_pinning_disabled
+    client = DuoApi.new(IKEY, SKEY, HOST, nil, disable_ca_pinning: true)
+    assert_equal(
+      "duo_api_ruby/#{DuoApi::VERSION} ca_bundle/#{DuoApi::CA_BUNDLE_VERSION} (ca_pinning=disable)",
+      client.send(:user_agent)
+    )
+  end
+end
+
+class TestUserAgentHeader < BaseTestCase
+  def setup
+    @client_pinned = DuoApi.new(IKEY, SKEY, HOST)
+    @client_unpinned = DuoApi.new(IKEY, SKEY, HOST, nil, disable_ca_pinning: true)
+    @mock_http = mock
+    @ok_resp = Net::HTTPSuccess.new('200')
+  end
+
+  def assert_user_agent_header(client, expected_state)
+    Net::HTTP.expects(:start).yields(@mock_http)
+    @mock_http.expects(:request).with do |request|
+      request['User-Agent'] ==
+        "duo_api_ruby/#{DuoApi::VERSION} ca_bundle/#{DuoApi::CA_BUNDLE_VERSION} (ca_pinning=#{expected_state})"
+    end.returns(@ok_resp)
+    client.request('GET', '/foo/bar')
+  end
+
+  def test_pinned_client_sets_user_agent_header
+    assert_user_agent_header(@client_pinned, 'enable')
+  end
+
+  def test_unpinned_client_sets_user_agent_header
+    assert_user_agent_header(@client_unpinned, 'disable')
+  end
+end