Function parseTarget

sidecar/server-demo/handler.go:247–271

parseTarget validates X-Lark-Proxy-Target and returns the host portion for HMAC input and allowlist lookup. The target must be "https:// " with no path, query, fragment, userinfo, or non-https scheme. Rejecting these shapes closes a token-leak channel: a compromised sandbox holding PROXY_KEY co

(target string)

// otherwise request cleartext HTTP forwarding (or inject a path to a different
// endpoint than the allowlist entry implies).
func parseTarget(target string) (host string, err error) {
	u, perr := url.Parse(target)
	if perr != nil {
		return "", fmt.Errorf("parse: %w", perr)
	}
	if u.Scheme != "https" {
		return "", fmt.Errorf("scheme must be https, got %q", u.Scheme)
	}
	if u.Host == "" {
		return "", fmt.Errorf("missing host")
	}
	if u.User != nil {
		return "", fmt.Errorf("userinfo not allowed")
	}
	if u.Path != "" && u.Path != "/" {
		return "", fmt.Errorf("path not allowed (got %q)", u.Path)
	}
	if u.RawQuery != "" {
		return "", fmt.Errorf("query not allowed")
	}
	if u.Fragment != "" {
		return "", fmt.Errorf("fragment not allowed")
	}
	return u.Host, nil
}