fix(node): allow IPv6-only addresses (#537)

go-backend/internal/http/handler/security_utils.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"fmt"
 	"net"
+	"net/netip"
 	"strings"
 )
 
@@ -75,6 +76,12 @@ func IsValidNodeAddress(addr string) error {
 	if strings.ContainsAny(addr, "/?") {
 		return fmt.Errorf("address must not contain path or query parameters")
 	}
+	// A bare IPv6 literal contains multiple colons, so net.SplitHostPort treats
+	// it as a malformed host:port pair. Accept IP literals before attempting
+	// host:port parsing; netip also handles scoped IPv6 addresses.
+	if _, err := netip.ParseAddr(addr); err == nil {
+		return nil
+	}
 
 	_, _, err := net.SplitHostPort(addr)
 	if err != nil {

go-backend/internal/http/handler/security_utils_test.go

@@ -0,0 +1,46 @@
+package handler
+
+import "testing"
+
+func TestIssue515IsValidNodeAddressAcceptsBareIPv6(t *testing.T) {
+	for _, addr := range []string{
+		"2001:db8::1",
+		"::1",
+		"fe80::1%eth0",
+	} {
+		t.Run(addr, func(t *testing.T) {
+			if err := IsValidNodeAddress(addr); err != nil {
+				t.Fatalf("expected bare IPv6 address %q to be accepted: %v", addr, err)
+			}
+		})
+	}
+}
+
+func TestIsValidNodeAddressKeepsExistingAddressForms(t *testing.T) {
+	for _, addr := range []string{
+		"203.0.113.10",
+		"node.example.com",
+		"node.example.com:6365",
+		"[2001:db8::1]:6365",
+	} {
+		t.Run(addr, func(t *testing.T) {
+			if err := IsValidNodeAddress(addr); err != nil {
+				t.Fatalf("expected node address %q to be accepted: %v", addr, err)
+			}
+		})
+	}
+}
+
+func TestIsValidNodeAddressRejectsURLComponents(t *testing.T) {
+	for _, addr := range []string{
+		"https://node.example.com",
+		"node.example.com/path",
+		"node.example.com?transport=tcp",
+	} {
+		t.Run(addr, func(t *testing.T) {
+			if err := IsValidNodeAddress(addr); err == nil {
+				t.Fatalf("expected node address %q to be rejected", addr)
+			}
+		})
+	}
+}