Re: [PATCH 3/8] ucounts: Fix and simplify RLIMIT_NPROC handling during setuid()+execve

[Michal Koutný]

On Mon, Feb 14, 2022 at 09:10:49AM -0600, "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> wrote:
> I really like how cleanly this patch seems to be.  Unfortunately it is
> wrong.

It seems [1] so:

setuid()		// RLIMIT_NPROC is fine at this moment
...		fork()
		...
...		fork()
execve()		// eh, oh

This "punishes" the exec'ing task although the cause is elsewhere.

Michal

[1] The decoupled setuid()+execve() check can be interpretted both ways.
I understood historically the excess at the setuid() moment is relevant.