Add a section to the config file for HTTP headers to add to responses

The example configuration files add X-Content-Type-Options: nosniff.

Add coverage in existing registry/handlers unit tests.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

cmd/registry/config-cache.yml

@@ -17,6 +17,8 @@ http:
     secret: asecretforlocaldevelopment
     debug:
         addr: localhost:5001
+    headers:
+        X-Content-Type-Options: [nosniff]
 redis:
   addr: localhost:6379
   pool:

cmd/registry/config-dev.yml

@@ -32,6 +32,8 @@ http:
     addr: :5000
     debug:
         addr: localhost:5001
+    headers:
+        X-Content-Type-Options: [nosniff]
 redis:
   addr: localhost:6379
   pool:

cmd/registry/config-example.yml

@@ -9,3 +9,5 @@ storage:
         rootdirectory: /var/lib/registry
 http:
     addr: :5000
+    headers:
+        X-Content-Type-Options: [nosniff]

configuration/configuration.go

@@ -86,6 +86,12 @@ type Configuration struct {
 			ClientCAs []string `yaml:"clientcas,omitempty"`
 		} `yaml:"tls,omitempty"`
 
+		// Headers is a set of headers to include in HTTP responses. A common
+		// use case for this would be security headers such as
+		// Strict-Transport-Security. The map keys are the header names, and
+		// the values are the associated header payloads.
+		Headers http.Header `yaml:"headers,omitempty"`
+
 		// Debug configures the http debug interface, if specified. This can
 		// include services such as pprof, expvar and other data that should
 		// not be exposed externally. Left disabled by default.

configuration/configuration_test.go

@@ -70,6 +70,7 @@ var configStruct = Configuration{
 			Key         string   `yaml:"key,omitempty"`
 			ClientCAs   []string `yaml:"clientcas,omitempty"`
 		} `yaml:"tls,omitempty"`
+		Headers http.Header `yaml:"headers,omitempty"`
 		Debug   struct {
 			Addr string `yaml:"addr,omitempty"`
 		} `yaml:"debug,omitempty"`
@@ -81,6 +82,9 @@ var configStruct = Configuration{
 		}{
 			ClientCAs: []string{"/path/to/ca.pem"},
 		},
+		Headers: http.Header{
+			"X-Content-Type-Options": []string{"nosniff"},
+		},
 	},
 }
 
@@ -118,6 +122,8 @@ reporting:
 http:
   clientcas:
     - /path/to/ca.pem
+  headers:
+    X-Content-Type-Options: [nosniff]
 `
 
 // inmemoryConfigYamlV0_1 is a Version 0.1 yaml document specifying an inmemory
@@ -136,6 +142,9 @@ notifications:
       url:  http://example.com
       headers:
         Authorization: [Bearer <example>]
+http:
+  headers:
+    X-Content-Type-Options: [nosniff]
 `
 
 type ConfigSuite struct {
@@ -192,6 +201,7 @@ func (suite *ConfigSuite) TestParseIncomplete(c *C) {
 	suite.expectedConfig.Auth = Auth{"silly": Parameters{"realm": "silly"}}
 	suite.expectedConfig.Reporting = Reporting{}
 	suite.expectedConfig.Notifications = Notifications{}
+	suite.expectedConfig.HTTP.Headers = nil
 
 	os.Setenv("REGISTRY_STORAGE", "filesystem")
 	os.Setenv("REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY", "/tmp/testroot")
@@ -366,5 +376,10 @@ func copyConfig(config Configuration) *Configuration {
 		configCopy.Notifications.Endpoints = append(configCopy.Notifications.Endpoints, v)
 	}
 
+	configCopy.HTTP.Headers = make(http.Header)
+	for k, v := range config.HTTP.Headers {
+		configCopy.HTTP.Headers[k] = v
+	}
+
 	return configCopy
 }

docs/configuration.md

@@ -163,6 +163,8 @@ information about each option that appears later in this page.
           - /path/to/another/ca.pem
       debug:
         addr: localhost:5001
+      headers:
+        X-Content-Type-Options: [nosniff]
     notifications:
       endpoints:
         - name: alistener
@@ -1147,6 +1149,8 @@ configuration may contain both.
           - /path/to/another/ca.pem
       debug:
         addr: localhost:5001
+      headers:
+        X-Content-Type-Options: [nosniff]
 
 The `http` option details the configuration for the HTTP server that hosts the registry.
 
@@ -1275,6 +1279,21 @@ The `debug` section takes a single, required `addr` parameter. This parameter
 specifies the `HOST:PORT` on which the debug server should accept connections.
 
 
+### headers
+
+The `headers` option is **optional** . Use it to specify headers that the HTTP
+server should include in responses. This can be used for security headers such
+as `Strict-Transport-Security`.
+
+The `headers` option should contain an option for each header to include, where
+the parameter name is the header's name, and the parameter value a list of the
+header's payload values.
+
+Including `X-Content-Type-Options: [nosniff]` is recommended, so that browsers
+will not interpret content as HTML if they are directed to load a page from the
+registry. This header is included in the example configuration files.
+
+
 ## notifications
 
     notifications:

registry/handlers/api_test.go

@@ -30,6 +30,10 @@ import (
 	"golang.org/x/net/context"
 )
 
+var headerConfig = http.Header{
+	"X-Content-Type-Options": []string{"nosniff"},
+}
+
 // TestCheckAPI hits the base endpoint (/v2/) ensures we return the specified
 // 200 OK response.
 func TestCheckAPI(t *testing.T) {
@@ -215,6 +219,7 @@ func TestURLPrefix(t *testing.T) {
 		},
 	}
 	config.HTTP.Prefix = "/test/"
+	config.HTTP.Headers = headerConfig
 
 	env := newTestEnvWithConfig(t, &config)
 
@@ -1009,6 +1014,8 @@ func newTestEnv(t *testing.T, deleteEnabled bool) *testEnv {
 		},
 	}
 
+	config.HTTP.Headers = headerConfig
+
 	return newTestEnvWithConfig(t, &config)
 }
 
@@ -1225,6 +1232,14 @@ func checkResponse(t *testing.T, msg string, resp *http.Response, expectedStatus
 
 		t.FailNow()
 	}
+
+	// We expect the headers included in the configuration
+	if !reflect.DeepEqual(resp.Header["X-Content-Type-Options"], []string{"nosniff"}) {
+		t.Logf("missing or incorrect header X-Content-Type-Options %s", msg)
+		maybeDumpResponse(t, resp)
+
+		t.FailNow()
+	}
 }
 
 // checkBodyHasErrorCodes ensures the body is an error body and has the

registry/handlers/app.go

@@ -428,6 +428,12 @@ type dispatchFunc func(ctx *Context, r *http.Request) http.Handler
 // handler, using the dispatch factory function.
 func (app *App) dispatcher(dispatch dispatchFunc) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		for headerName, headerValues := range app.Config.HTTP.Headers {
+			for _, value := range headerValues {
+				w.Header().Add(headerName, value)
+			}
+		}
+
 		context := app.context(w, r)
 
 		if err := app.authorized(w, r, context); err != nil {