Add check for empty deviceID in target URI template evaluation

authority/provisioner/wire/dpop_options.go

@@ -3,6 +3,7 @@ package wire
 import (
 	"bytes"
 	"crypto"
+	"errors"
 	"fmt"
 	"text/template"
 
@@ -24,6 +25,9 @@ func (o *DPOPOptions) GetSigningKey() crypto.PublicKey {
 }
 
 func (o *DPOPOptions) EvaluateTarget(deviceID string) (string, error) {
+	if deviceID == "" {
+		return "", errors.New("deviceID must not be empty")
+	}
 	buf := new(bytes.Buffer)
 	if err := o.target.Execute(buf, struct{ DeviceID string }{DeviceID: deviceID}); err != nil {
 		return "", fmt.Errorf("failed executing dpop template: %w", err)

authority/provisioner/wire/dpop_options_test.go

@@ -0,0 +1,58 @@
+package wire
+
+import (
+	"errors"
+	"testing"
+	"text/template"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDPOPOptions_EvaluateTarget(t *testing.T) {
+	tu := "http://wire.com:15958/clients/{{.DeviceID}}/access-token"
+	target, err := template.New("DeviceID").Parse(tu)
+	require.NoError(t, err)
+	fail := "https://acme.elna.wire.link/clients/{{.DeviceId}}/access-token" //
+	failTarget, err := template.New("DeviceID").Parse(fail)
+	require.NoError(t, err)
+	type fields struct {
+		target *template.Template
+	}
+	type args struct {
+		deviceID string
+	}
+	tests := []struct {
+		name        string
+		fields      fields
+		args        args
+		want        string
+		expectedErr error
+	}{
+		{
+			name: "ok", fields: fields{target: target}, args: args{deviceID: "deviceID"}, want: "http://wire.com:15958/clients/deviceID/access-token",
+		},
+		{
+			name: "fail/empty", fields: fields{target: target}, args: args{deviceID: ""}, expectedErr: errors.New("deviceID must not be empty"),
+		},
+		{
+			name: "fail/template", fields: fields{target: failTarget}, args: args{deviceID: "bla"}, expectedErr: errors.New(`failed executing dpop template: template: DeviceID:1:38: executing "DeviceID" at <.DeviceId>: can't evaluate field DeviceId in type struct { DeviceID string }`),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			o := &DPOPOptions{
+				target: tt.fields.target,
+			}
+			got, err := o.EvaluateTarget(tt.args.deviceID)
+			if tt.expectedErr != nil {
+				assert.EqualError(t, err, tt.expectedErr.Error())
+				assert.Empty(t, got)
+				return
+			}
+
+			assert.NoError(t, err)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}