Creating rooms and corridors by Random dungeon generation

I want to create Dungeon Random Generation system. I know about how to do this, except of one thing.

How can I make a different(random) length, width and height of the room / corridors, and impose on them the texture?

I see only two versions:

1. Use prefabs of corridors and rooms, randomly connected by the edges (doors).

2. Using a primitive Unity cube, set height ~0.1 and use it to make a floor for rooms and corridors (randomly). Then create a wall and put textures .