Shahar Liberman focused on enhancing permission-check reliability in overlay-based storage layers for the containers/storage and containers/container-libs repositories. He addressed permission-denied errors by updating the Exists() and Lexists() functions to use the AT_EACCESS flag with faccessat, ensuring that existence checks accurately reflected effective user permissions and Linux capabilities. Working in Go and leveraging deep knowledge of Linux system calls and file system operations, Shahar’s changes improved the security and predictability of storage operations in multi-user and CI environments. His cross-repository fixes contributed to more maintainable code and reduced operational friction when managing container storage layers under complex permissions.