autocert: exclude non-https routes (#5733)

Exclude non-https routes from the domains eligible for autocert.

internal/autocert/manager.go

@@ -496,8 +496,8 @@ func sourceHostnames(cfg *config.Config) []string {
 
 	dedupe := map[string]struct{}{}
 	for p := range cfg.Options.GetAllPolicies() {
-		if u, _ := urlutil.ParseAndValidateURL(p.From); u != nil && !strings.Contains(u.Host, "*") {
+		if h := eligibleHostname(p); h != "" {
-			dedupe[u.Hostname()] = struct{}{}
+			dedupe[h] = struct{}{}
 		}
 	}
 	if cfg.Options.AuthenticateURLString != "" {
@@ -520,6 +520,24 @@ func sourceHostnames(cfg *config.Config) []string {
 	return h
 }
 
+var eligibleSchemes = map[string]struct{}{
+	"https":     {},
+	"tcp+https": {},
+	"udp+https": {},
+}
+
+// eligibleHostname accepts a route and returns the hostname, if eligible for use
+// with autocert, or the empty string if not.
+func eligibleHostname(p *config.Policy) string {
+	u, _ := urlutil.ParseAndValidateURL(p.From)
+	if u == nil || strings.Contains(u.Host, "*") {
+		return ""
+	} else if _, ok := eligibleSchemes[u.Scheme]; !ok {
+		return ""
+	}
+	return u.Hostname()
+}
+
 func shouldEnableHTTPChallenge(cfg *config.Config) bool {
 	if cfg == nil || cfg.Options == nil {
 		return false

internal/autocert/manager_test.go

@@ -231,7 +231,7 @@ func TestConfig(t *testing.T) {
 	require.NoError(t, err)
 
 	p1 := config.Policy{
-		From: "http://from.example.com", To: to,
+		From: "https://from.example.com", To: to,
 	}
 	_ = p1.Validate()
 
@@ -631,6 +631,29 @@ func Test_configureTrustedRoots(t *testing.T) {
 	}
 }
 
+func Test_sourceHostnames(t *testing.T) {
+	t.Parallel()
+
+	cfg := &config.Config{
+		Options: config.NewDefaultOptions(),
+	}
+	cfg.Options.Policies = []config.Policy{
+		{From: "https://foo.example.com"},
+		{From: "http://non-https-route.example.com"},
+		{From: "https://bar.example.com:5443"},
+		{From: "ssh://ssh-hostname"},
+		{From: "tcp+https://baz.example.com:1234"},
+		{From: "udp+https://quux.example.com:5678"},
+	}
+
+	assert.ElementsMatch(t, []string{
+		"foo.example.com",
+		"bar.example.com",
+		"baz.example.com",
+		"quux.example.com",
+	}, sourceHostnames(cfg))
+}
+
 func TestShouldEnableHTTPChallenge(t *testing.T) {
 	t.Parallel()