The purpose of assignment is to check the authenticity of the user executing the system call, and prevent certain users from executing, kind of like certain security programs (although I don't exactly know how they work). On Sat, Jul 8, 2017 at 8:50 PM, Greg KH <greg@kroah.com> wrote:
On Sat, Jul 08, 2017 at 07:53:31PM +0530, Ajinkya Surnis wrote:
Actually, I've been given an assignment to write a kernel module such that whenever a certain system call (e.g. open()) is executed, the control should come to my new module; then it will do some processing on the parameters and then call the actual syscall function (sys_open()).
Horrible assignment, please pass along my regards to the professor that this is not anything that should ever be assigned. Seriously, do you want me to email them this?
I only found the way of intercepting 'sys_call_table'. I know this kind of hacking is probably not a good idea. Can you suggest any alternative way? I would really appreciate.
Don't do it.
Really, this is not a valid thing to do in Linux.
Feel free to quote me.
Also, the assignment said nothing about 2 modules, so are you sure you are even doing this right? :)
thanks,
greg k-h