Re: [PATCH 3/3] ptrace: do not use task_lock() for attach

[Chris Wright]

* Oleg Nesterov (oleg@xxxxxxxxxx) wrote:
> But this can happen without this change too?
> 
> - cpu2 takes task_lock(), tracehook_tracer_task() returns NULL because
>   we are not traced yet.
> 
> - cpu1 does ptrace_attach() and succeds, because cpu2 didn't update sid
>   yet
> 
> - cpu2 continues, it doesn't check avc_has_perm() (tracer == 0) and
>   updates sid.
> 
> No?

Yes.

> Shouldn't selinux_setprocattr() take ->cred_exec_mutex, like we do in
> selinux_bprm_set_creds() path?

I was looking at the same, seems like it to me.  James?

thanks,
-chris
> 
> Oleg.
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