Re: [RFC][PATCH] sysctl: Remove the sysctl system call

[Kees Cook]

On Tue, Oct 01, 2019 at 01:36:32PM -0500, Eric W. Biederman wrote:
> 
> This system call has been deprecated almost since it was introduced, and
> in a survey of the linux distributions I can no longer find any of them
> that enable CONFIG_SYSCTL_SYSCALL.  The only indication that I can find
> that anyone might care is that a few of the defconfigs in the kernel
> enable CONFIG_SYSCTL_SYSCALL.  However this appears in only 31 of 414
> defconfigs in the kernel, so I suspect this symbols presence is simply
> because it is harmless to include rather than because it is necessary.
> 
> As there appear to be no users of the sysctl system call, remove the
> code.  As this removes one of the few uses of the internal kernel mount
> of proc I hope this allows for even more simplifications of the proc
> filesystem.

I'm for it. :) I tripped over this being deprecated over a decade ago. :P

I think you can actually take this further and remove (or at least
empty) the uapi/linux/sysctl.h file too.

-- 
Kees Cook