shadow1ng/fscan · error
auth function is nil
Error message
auth function is nil
What it means
TestSingleCredential was invoked with a nil authFn — the function responsible for performing an auth attempt against a target. Since no test can run, it returns an AuthResult with Success:false, ErrorTypeUnknown, and the 'auth function is nil' error. This is a programming/configuration bug, not a network outcome.
Source
Thrown at plugins/services/credential_tester.go:86
func authCleanupWait() time.Duration {
return time.Duration(atomic.LoadInt64(&authCleanupWaitNanos))
}
// =============================================================================
// 单凭据测试（解决 goroutine 泄漏）
// =============================================================================
// TestSingleCredential 安全地测试单个凭据
// 正确处理 context 取消时的资源清理
func TestSingleCredential(ctx context.Context, cred Credential, authFn AuthFunc) *AuthResult {
if ctx == nil {
ctx = context.Background()
}
if authFn == nil {
return &AuthResult{
Success: false,
ErrorType: ErrorTypeUnknown,
Error: fmt.Errorf("auth function is nil"),
}
}
if err := ctx.Err(); err != nil {
return &AuthResult{
Success: false,
ErrorType: ErrorTypeNetwork,
Error: err,
}
}
resultChan := make(chan *AuthResult, 1)
go func() {
defer func() {
if r := recover(); r != nil {
resultChan <- &AuthResult{
Success: false,
ErrorType: ErrorTypeUnknown,View on GitHub (pinned to 95cc12e753)
Solutions
- Fix the caller to construct and pass a non-nil authFn (e.g. p.createAuthFunc(info, config, state)) before invoking TestSingleCredential.
- Add an early check in the calling plugin so nil authFn is caught and reported with plugin context.
- In tests, this is expected behavior — assert on ErrorTypeUnknown and the message rather than treating it as a scan failure.
Example fix
// before result := TestSingleCredential(ctx, target, cred, nil, state) // after authFn := p.createAuthFunc(info, config, state) result := TestSingleCredential(ctx, target, cred, authFn, state)
Defensive patterns
Strategy: validation
Validate before calling
if authFn == nil {
return fmt.Errorf("plugin %s produced nil auth function; check createAuthFunc wiring", pluginName)
}
result := TestSingleCredential(ctx, target, cred, authFn, state) Try / catch
res := TestSingleCredential(ctx, target, cred, authFn, state)
if !res.Success && res.ErrorType == ErrorTypeUnknown && res.Error.Error() == "auth function is nil" {
log.Printf("tester misconfigured: authFn missing for %s", target)
} Prevention
- Always build authFn via the plugin's createAuthFunc before constructing the tester.
- Assert non-nil authFn in plugin initialization tests.
- Watch for nil returns from factory functions and fail fast at startup rather than mid-scan.
When it happens
Trigger: testCredentialWithRetry (or tests) calls TestSingleCredential without supplying an authFn, e.g. a plugin forgot to build its auth function via createAuthFunc or passed an uninitialized function variable.
Common situations: Plugin registration code that constructs the tester before wiring authFn; refactor left authFn unassigned; a nil return from createAuthFunc on a misconfigured plugin passed straight through.
Related errors
AI-assisted analysis of shadow1ng/fscan@95cc12e753 (2026-09-06).
Data as JSON: /api/errors/73299af115d95d4a.
Report an issue: GitHub.