Is it permissible for a female worker in a school cafeteria, which is part of a private company, to buy goods and sell them on her own account within the cafeteria to improve her income, knowing that her salary is insufficient?

A worker in a cafeteria or similar establishment is considered a private employee (ajeer khass). The private employee's labor is exclusively owned by the employer throughout the duration of the contract. Therefore, it is not permissible for him to spend his time on anything other than the tasks he is assigned without the employer's permission, even if the salary is low. This is because a private employee earns his wage based on time, not on the amount of work performed. He is not permitted to work for anyone other than his employer without the latter's permission. If he works for someone else and thereby harms the employer, he must compensate the employer for the loss of his labor.