You'd most likely need a permit, yes. Not many places just let you set up outside, and there are health/safety codes you'd have to meet unless you enjoy getting sued for food poisoning. I know in my city food trucks and carts are rather severely over-regulated, but your location might be more lax on that.

Whether or not you need a permit depends on where you live.

There is a liquor store down the block from my home, and there is a popular dive bar next to it. I've become friends with the store owner, should I ask the owner if I can sell food outside his store (next to the bar)? I'm thinking hotdogs or quesadillas. Would I need a food permit?