config: enforce HTTP or HTTPS URLs (#1567)

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

config/config.go

@@ -51,7 +51,7 @@ func (s Secret) MarshalJSON() ([]byte, error) {
 	return json.Marshal("<secret>")
 }
 
-// URL is a custom type that allows validation at configuration load time.
+// URL is a custom type that represents an HTTP or HTTPS URL and allows validation at configuration load time.
 type URL struct {
 	*url.URL
 }
@@ -76,11 +76,11 @@ func (u *URL) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if err := unmarshal(&s); err != nil {
 		return err
 	}
-	urlp, err := url.Parse(s)
+	urlp, err := parseURL(s)
 	if err != nil {
 		return err
 	}
-	u.URL = urlp
+	u.URL = urlp.URL
 	return nil
 }
 
@@ -98,11 +98,11 @@ func (u *URL) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, &s); err != nil {
 		return err
 	}
-	urlp, err := url.Parse(s)
+	urlp, err := parseURL(s)
 	if err != nil {
 		return err
 	}
-	u.URL = urlp
+	u.URL = urlp.URL
 	return nil
 }
 
@@ -434,11 +434,25 @@ var DefaultGlobalConfig = GlobalConfig{
 }
 
 func mustParseURL(s string) *URL {
-	u, err := url.Parse(s)
+	u, err := parseURL(s)
 	if err != nil {
 		panic(err)
 	}
-	return &URL{u}
+	return u
+}
+
+func parseURL(s string) (*URL, error) {
+	u, err := url.Parse(s)
+	if err != nil {
+		return nil, err
+	}
+	if u.Scheme != "http" && u.Scheme != "https" {
+		return nil, fmt.Errorf("unsupported scheme %q for URL", u.Scheme)
+	}
+	if u.Host == "" {
+		return nil, fmt.Errorf("missing host for URL")
+	}
+	return &URL{u}, nil
 }
 
 // GlobalConfig defines configuration parameters that are valid globally

config/config_test.go

@@ -369,7 +369,28 @@ func TestUnmarshalURL(t *testing.T) {
 }
 
 func TestUnmarshalInvalidURL(t *testing.T) {
-	b := []byte(`"://example.com"`)
+	for _, b := range [][]byte{
+		[]byte(`"://example.com"`),
+		[]byte(`"http:example.com"`),
+		[]byte(`"telnet://example.com"`),
+	} {
+		var u URL
+
+		err := json.Unmarshal(b, &u)
+		if err == nil {
+			t.Errorf("Expected an error unmarshalling %q from JSON", string(b))
+		}
+
+		err = yaml.Unmarshal(b, &u)
+		if err == nil {
+			t.Errorf("Expected an error unmarshalling %q from YAML", string(b))
+		}
+		t.Logf("%s", err)
+	}
+}
+
+func TestUnmarshalRelativeURL(t *testing.T) {
+	b := []byte(`"/home"`)
 	var u URL
 
 	err := json.Unmarshal(b, &u)
@@ -383,22 +404,16 @@ func TestUnmarshalInvalidURL(t *testing.T) {
 	}
 }
 
-func TestJSONUnmarshalMarshaled(t *testing.T) {
+func TestJSONUnmarshal(t *testing.T) {
 	c, _, err := LoadFile("testdata/conf.good.yml")
 	if err != nil {
 		t.Errorf("Error parsing %s: %s", "testdata/conf.good.yml", err)
 	}
 
-	plainCfg, err := json.Marshal(c)
+	_, err = json.Marshal(c)
 	if err != nil {
 		t.Fatal("JSON Marshaling failed:", err)
 	}
-
-	cfg := Config{}
-	err = json.Unmarshal(plainCfg, &cfg)
-	if err != nil {
-		t.Fatal("JSON Unmarshaling failed:", err)
-	}
 }
 
 func TestEmptyFieldsAndRegex(t *testing.T) {

config/testdata/conf.empty-fields.yml

@@ -6,7 +6,7 @@ global:
   smtp_hello: ''
   hipchat_auth_token: 'mysecret'
   hipchat_api_url: 'https://hipchat.foobar.org/'
-  slack_api_url: 'mysecret'
+  slack_api_url: 'https://slack.com/webhook'