09e4bc8a30
PipelineLogWriter derives its subdirectory from the caller-controlled user_id prefix before "__". That prefix was joined directly to the log root, so an absolute prefix or ".." escaped it: user_id="/tmp/evil__u1" created /tmp/evil and appended the daily log there. Whitelist a single safe path component and, as defence in depth, verify the resolved directory stays under the configured root. Sanitize default_subdir the same way. Add regressions for absolute, parent and nested prefixes plus a malicious default subdir. Co-authored-by: qiye.sjh <shijiahao_0802@youzan.com> Co-authored-by: Claude Code <noreply@anthropic.com>