Hostname handling fixes

spnego.go

@@ -32,3 +32,24 @@ func canonicalizeHostname(hostname string) (string, error) {
 
 	return strings.TrimRight(names[0], "."), nil
 }
+
+func getHostname(req *http.Request, canonicalize bool) (string, error) {
+	var err error
+
+	h := req.URL.Host // SPN should contain the port, if non-standard (https://social.technet.microsoft.com/wiki/contents/articles/717.service-principal-names-spn-setspn-syntax.aspx)
+	if req.Host != "" {
+		h = req.Host
+	}
+	// I can't think why you'd want to canonicalize an overridden Host
+	// header (you're likely to get the hostname in the URL, which is what
+	// you're overriding in the first place). But since it can be disabled,
+	// leave it here in the flow so that Host header hostnames can be
+	// canonicalized if desired.
+	if canonicalize {
+		if h, err = canonicalizeHostname(h); err != nil {
+			return "", err
+		}
+	}
+
+	return h, nil
+}

spnego_gokrb5.go

@@ -68,12 +68,9 @@ func (k *krb5) makeClient() error {
 }
 
 func (k *krb5) SetSPNEGOHeader(req *http.Request, canonicalize bool) error {
-	h := req.URL.Hostname()
-	if canonicalize {
-		var err error
-		if h, err = canonicalizeHostname(h); err != nil {
-			return err
-		}
+	h, err := getHostname(req, canonicalize)
+	if err != nil {
+		return err
 	}
 
 	if err := k.makeCfg(); err != nil {

spnego_test.go

@@ -0,0 +1,129 @@
+package spnego
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+)
+
+func TestGetHostnameEmptyHost(t *testing.T) {
+	desired := "example.com"
+
+	url, err := url.Parse("http://example.com/path")
+	if err != nil {
+		panic(err)
+	}
+	req := &http.Request{
+		URL: url,
+	}
+	t.Logf("url %s, host %s\n", req.URL.Host, req.Host)
+
+	h, err := getHostname(req, false)
+	if err != nil {
+		panic(err)
+	}
+
+	if h != desired {
+		t.Errorf("Hostname was incorrect: wanted %s, got %s.", desired, h)
+	}
+}
+
+func TestGetHostnameEmptyHostPort(t *testing.T) {
+	desired := "example.com:8080"
+
+	url, err := url.Parse("http://example.com:8080/path")
+	if err != nil {
+		panic(err)
+	}
+	req := &http.Request{
+		URL: url,
+	}
+	t.Logf("url %s, host %s\n", req.URL.Host, req.Host)
+
+	h, err := getHostname(req, false)
+	if err != nil {
+		panic(err)
+	}
+
+	if h != desired {
+		t.Errorf("Hostname was incorrect: wanted %s, got %s.", desired, h)
+	}
+}
+
+func TestGetHostnameHost(t *testing.T) {
+	desired := "example.com"
+
+	req, err := http.NewRequest("GET", "http://example.com/path", nil)
+	if err != nil {
+		panic(err)
+	}
+	t.Logf("url %s, host %s\n", req.URL.Host, req.Host)
+
+	h, err := getHostname(req, false)
+	if err != nil {
+		panic(err)
+	}
+
+	if h != desired {
+		t.Errorf("Hostname was incorrect: wanted %s, got %s.", desired, h)
+	}
+}
+
+func TestGetHostnameHostWithPort(t *testing.T) {
+	desired := "example.com:8080"
+
+	req, err := http.NewRequest("GET", "http://example.com:8080/path", nil)
+	if err != nil {
+		panic(err)
+	}
+	t.Logf("url %s, host %s\n", req.URL.Host, req.Host)
+
+	h, err := getHostname(req, false)
+	if err != nil {
+		panic(err)
+	}
+
+	if h != desired {
+		t.Errorf("Hostname was incorrect: wanted %s, got %s.", desired, h)
+	}
+}
+
+func TestGetHostnameOverride(t *testing.T) {
+	desired := "override.org"
+
+	req, err := http.NewRequest("GET", "http://example.com:8080/path", nil)
+	if err != nil {
+		panic(err)
+	}
+	req.Host = "override.org"
+	t.Logf("url %s, host %s\n", req.URL.Host, req.Host)
+
+	h, err := getHostname(req, false)
+	if err != nil {
+		panic(err)
+	}
+
+	if h != desired {
+		t.Errorf("Hostname was incorrect: wanted %s, got %s.", desired, h)
+	}
+}
+
+func TestGetHostnameOverrideWithPort(t *testing.T) {
+	desired := "override.org:1234"
+
+	req, err := http.NewRequest("GET", "http://example.com:8080/path", nil)
+	if err != nil {
+		panic(err)
+	}
+	req.Host = "override.org:1234"
+	t.Logf("url %s, host %s\n", req.URL.Host, req.Host)
+
+	h, err := getHostname(req, false)
+	if err != nil {
+		panic(err)
+	}
+
+	if h != desired {
+		t.Errorf("Hostname was incorrect: wanted %s, got %s.", desired, h)
+	}
+}

spnego_windows.go

@@ -19,12 +19,9 @@ func New() Provider {
 
 // SetSPNEGOHeader puts the SPNEGO authorization header on HTTP request object
 func (s *sspi) SetSPNEGOHeader(req *http.Request, canonicalize bool) error {
-	h := req.URL.Hostname()
-	if canonicalize {
-		var err error
-		if h, err = canonicalizeHostname(h); err != nil {
-			return err
-		}
+	h, err := getHostname(req, canonicalize)
+	if err != nil {
+		return err
 	}
 	spn := "HTTP/" + h