I forgot to say that I am using Linux. and I think weh I compiled the Kernel I saw some exec files types, 3 types.
Suppose every files I get I chmod to suppose 555 (RW) will it be OK? as It won't be a executable file.

My problem is, that I will be receiving uploads, and I want to have some precoution to avoid virus., is there any good ant-virus in Linux? amd I wanted to the extensions that I can just ignore.