On Tue, 7 Jan 2003 12:28:42 +0530 (IST) Nikhil Joshi wrote:
AFAIK 386 gives you the reqd previlege levels
If you're talking of the protected and unprotected modes of operation in ix86 CPUs, the last I heard, Linux kernel operates entirely in protected mode. AFAIK, none of the modern OSes use that feature - someone please check this and correct me if I'm wrong.
Now how is kernel to decide (if it had powers/facility) whether program is virus or not?
e.g. a simple shell script like
rm -rf * or cat < /dev/null > *.txt
^^ Ambiguous redirect - won't work
maybe useful for someone or virus for others
Kernel doesn't decide whether a script is a virus or not. All it checks is whether a process is authorized to do what it's trying to do. This itself goes a long way in keeping things secure. And it goes beyond simple deletion of files and formatting of disks.