Is there a legal basis for prohibiting taking pictures in shopping malls?

From the perspective of jurisprudence, large commercial occasions or shops are not public places, but private places open to the public. Shopkeepers have the right to stipulate the rules of conduct after entering the store, but at the same time they have the obligation to ensure the personal safety in the store is protected. These are the so-called rights and obligations, so there is no question of legitimacy. Just like entering some western restaurants, you are not allowed to eat food other than that provided by this restaurant. This is not so-called injustice.

Your confusion is mainly about taking photos in public, and there is no problem of invasion of privacy in taking photos in public. Public places are spaces open to the public, such as public transportation, city streets, squares, parks, stations, shops, docks, airports, etc. These places are open to anyone who is not specific. On such occasions, anyone can record what he has seen and heard without the consent of the parties, except that taking pictures is prohibited by law.

Of course, it is different in private places, and the consent of the parties must be obtained, otherwise it is infringement. In the current news practice, people are used to saying that reporters' unannounced visits are "secretly recorded". Actually, this statement is wrong. Recording what you see and hear in public places does not exist as "stealing", but only in private places. Of course, if the parties agree, they can also be exempted.