how to get filename of execve() system call from kernel module which install hook to syscall table to intercept original syscall in kernels before 4.2 and atter 4.2 ? X86_64

[greg@kroah.com (Greg KH)]

On Mon, Mar 06, 2017 at 10:18:26AM +0300, Lev Olshvang wrote:
> Hello all,
> 
>  In kernels 3.X up to 4.2 execve(|) system call was  for x86_64 architecture the the system call was made through some 
> magic ( I can't say I understand it ) assembly stub in arch/x86/kernel/entry_64.S
> so up to kernel 4.2 it was possble to patch this assembly to install the hook, ex. see 
> http://stackoverflow.com/questions/8372912/hooking-sys-execve-on-linux-3-x/9672512#9672512
> 
> But this hook still can't access  in a proper way filename argument, althouth I tried to do it with in the same way as 
> fs/exec.c does : using  kernel's getname() function (which I was need to find through kallsyms_lookup_name() 
>  
> In kernels 4.2 and up, the arch/x86/kernel/entry_64.S is gone, and I still dont' have a clue what to do to get filename as a char string.

Why do you want to hook a syscall?  that's a very complex, and broken,
and ill-advised thing to do.  Please don't do that.

What problem are you trying to solve here that led you to think that
putting a syscall hook in is a good solution?

thanks,

greg k-h