LSM stacking in next for 6.1?

[Tetsuo Handa]

On 2022/09/09 7:56, Casey Schaufler wrote:
> Good idea. I'm reading the official how-to-write-a-syscall documentation.

Can't we use prctl() syscall? We can assign an LSM ID when an (built-in or loadable) LSM
is loaded, and pass that LSM ID as one of arguments for prctl().

Since we have security_task_prctl(option, arg2, arg3, arg4, arg5) inside prctl(), an LSM 
which was assigned that LSM ID upon load checks arguments (including PID argument).
That will be something like ioctl() without open("/proc/pid/*/attr/*").