Re: [PATCH] fs: exec: apply CLOEXEC before changing dumpable task flags

From: Oleg Nesterov
Date: Tue Dec 20 2016 - 12:30:41 EST


On 12/20, Aleksa Sarai wrote:
>
> @@ -1287,6 +1287,13 @@ void setup_new_exec(struct linux_binprm * bprm)
> /* This is the point of no return */
> current->sas_ss_sp = current->sas_ss_size = 0;
>
> + /*
> + * We have to apply CLOEXEC before we change whether the process is
> + * dumpable to avoid a race with a process in userspace trying to access
> + * the should-be-closed file descriptors of a process undergoing exec(2).
> + */
> + do_close_on_exec(current->files);

Cosmetic, but perhaps this should go into flush_old_exec() then?

But I am fine either way, up to you.

Oleg.