Re: [PATCH v1 6/8] x86/entry/clearregs: Add number of arguments to syscall tables

[Andy Lutomirski]

> On Jan 9, 2018, at 5:03 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> 
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> 
> In order to sanitize the system call arguments properly
> we need to know the number of syscall arguments for each
> syscall. Add a new column to the 32bit and 64bit syscall
> tables to list the number of arguments.
> 

Surely we can do this in the SYSCALL_DEFINE macros.  Or at least statically check it.

Also, what attack are we protecting against anyway?