OK, but "one may" sounds pretty formal to me (I don't know anyone who'd actually say it); "you can" or at a pinch "one can" is more natural.
Incidentally, "one" is usually reserved for written, especially academic, texts, where "one may" is usually used to refer to possibility rather than permission, I think. It would not normally be used in a notice or list of youth hostel conditions, for example, or by the "owners" of the room. "One can" might be used by a third party describing the situation, on TripAdvisor, for example, or perhaps by some extremely posh (or perhaps pretentious) British users of the room using "one" to mean "we"!
But in the British Highway Code, for example, it's all "You can ..., You must ..., You can't ..."
I have that problem, most of my error are through carelessness, I don't check what write. I hate that, I worked as a printer for 17 years and usually catch everyone's typos but my own. What can I say, just celebrated my 83rd birthday on the 20th. Getting sloppy in my middle age. Moje urodzinie
"It is allowed to cook in this room" is not correct for this sentence in English.
Alternatives would be: You can cook here (most common)
One may cook here (formal, only in writing)
Cooking is allowed here (second most common)
Cooking is permitted here (also sounds kind of bookish and formal)
"It is allowed to cook in the room" is a crummy sentance. What is allowed to cook in this room? Are you refering to the perso cooking as an it? They chicken is allowed to cook in this room? Is it a crummy sentance in Polish, too? Or is there something that is lost in translation?
It generally is allowed. The 'it' that doesn't refer to anything special is used here. As it seems that a lot of people dislike this construction, I guess I may leave "One may cook in this room" as the only starred answer. Although frankly, "it is allowed" seems to be closer grammatically.