Re: [PATCH v8 3/9] seccomp: introduce writer locking

From: Oleg Nesterov
Date: Wed Jun 25 2014 - 14:08:51 EST


On 06/24, Kees Cook wrote:
>
> +static void copy_seccomp(struct task_struct *p)
> +{
> +#ifdef CONFIG_SECCOMP
> + /*
> + * Must be called with sighand->lock held, which is common to
> + * all threads in the group. Regardless, nothing special is
> + * needed for the child since it is not yet in the tasklist.
> + */
> + BUG_ON(!spin_is_locked(&current->sighand->siglock));
> +
> + get_seccomp_filter(current);
> + p->seccomp = current->seccomp;
> +
> + if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
> + set_tsk_thread_flag(p, TIF_SECCOMP);
> +#endif
> +}

Wait. But what about no_new_privs? We should copy it as well...

Perhaps this helper should be updated a bit and moved into seccomp.c so
that seccomp_sync_threads() could use it too.

Oleg.

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