hashicorp/nomad · error

failed to convert user domain to UTF-16: %w

Error message

failed to convert user domain to UTF-16: %w

What it means

createUserToken converts the domain portion of 'DOMAIN\\user' to a UTF-16 pointer for LogonUserW. syscall.UTF16PtrFromString fails if the domain string contains an interior NUL byte, so token creation aborts before calling LogonUser.

Source

Thrown at drivers/shared/executor/executor_windows.go:88

var (
	advapiDll      = windows.NewLazySystemDLL("advapi32.dll")
	procLogonUserW = advapiDll.NewProc("LogonUserW")
)

const (
	_LOGON_SERVICE    uint32 = 5
	_PROVIDER_DEFAULT uint32 = 0
)

func createUserToken(domain, username string) (*syscall.Token, error) {
	userw, err := syscall.UTF16PtrFromString(username)
	if err != nil {
		return nil, fmt.Errorf("failed to convert username to UTF-16: %w", err)
	}
	domainw, err := syscall.UTF16PtrFromString(domain)
	if err != nil {
		return nil, fmt.Errorf("failed to convert user domain to UTF-16: %w", err)
	}
	var token syscall.Token
	ret, _, e := procLogonUserW.Call(
		uintptr(unsafe.Pointer(userw)),
		uintptr(unsafe.Pointer(domainw)),
		uintptr(unsafe.Pointer(nil)),
		uintptr(_LOGON_SERVICE),
		uintptr(_PROVIDER_DEFAULT),
		uintptr(unsafe.Pointer(&token)),
	)
	if ret == 0 {
		return nil, e
	}

	return &token, nil
}

func (e *UniversalExecutor) ListProcesses() set.Collection[int] {

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Inspect the domain portion of the user value for embedded NUL/control characters and fix its source.
2. Sanitize the domain string to printable characters before executor setup.
3. Correct the task user format, e.g. 'DOMAIN\\user'.

Example fix

// before
user = "CORP\x00\\appuser"
// after
user = "CORP\\appuser"

// Go: reject domains containing NUL before calling the executor
if strings.ContainsRune(domain, 0) {
    return errors.New("domain must not contain NUL bytes")
}

func utf16Safe(s string) bool {
    _, err := syscall.UTF16PtrFromString(s)
    return err == nil
}

if err := exec.SetUser(cmd, user); err != nil {
    if strings.Contains(err.Error(), "convert user domain to UTF-16") {
        return fmt.Errorf("malformed domain in user value %q", user)
    }
    return err
}

When it happens

Trigger: The domain string (nameParts[0] after splitting user on '\\') contains a NUL character.

Common situations: Same as the username variant: corrupted or programmatically mangled user strings; binary contamination in config from a template or plugin.

Related errors

• failed to convert username to UTF-16: %w
• failed to convert "%s" to UTF16: %v
• failed to create user token: %w
• eventlog.level must be one of INFO, WARN, or ERROR
• running container as ContainerAdmin is unsafe; change the co

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/8bbfb3af12e0064f. Report an issue: GitHub.