هل من القانوني أن يحتفظ صاحب العمل بجواز سفر العامل؟

Of course, it is illegal for the company to hold the passport of employees.

The passport actually does not even belong to the holder of the passport; it belongs to the issuing government and no one is entitled to hold this document but the one who has his name on it.

That being said, the standard practice here in the UAE that most of the companies' policies tend to keep/hold the passports of their employees so that they will not run away, especially people who have positions in accounts or will be exposed to private and confidential information of the company.

To sum up, it is not legal, but companies do this and usually, if you say no, they tell you it's a company policy and if you do not want to leave it we will have to terminate you or give your resignation...etc.