Do I need permission to host files?

I want to host some files for G1 and G2 on my site: the official G1 patch, the systempack and related files, DirectX 11, Lihiver, Odyssey, Returning, texture packs, etc. Do I need permission to do this?

I can't give legally binding permissions of course, but I think you can do that without any issues. Normally you'd want to ask permission to host any official files though. But as they are freely available anyways (I guess) I don't see any harm doing it.
Just make sure you are not like hosting a complete and patched version of the game. Unless you have a clear permission to do that, and the game can be given away for free, that's a completely different kind of thing.
But as long as it's just patches and mods which you cannot use without the original game itself, I don't see any issues. And if in doubt, just ask the developer Piranha Bytes. While they might or might not have the rights anymore they can surely give you a clear answer, and from what I have heared an interviews and so on, they are kinda open, laid back and semi-indie and I am pretty sure they will answer.