linux-kernel - Re: [PATCH 1/1] pid_namespace: pidns_get() should check task_active_pid

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 02 Apr 2014 09:53:33 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Matthew Dempsky <mdempsky@...omium.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Kees Cook <keescook@...omium.org>,
	Julien Tinnes <jln@...omium.org>,
	Roland McGrath <mcgrathr@...omium.org>,
	Jan Kratochvil <jan.kratochvil@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] pid_namespace: pidns_get() should check task_active_pid_ns() != NULL

Oleg Nesterov <oleg@...hat.com> writes:

> pidns_get()->get_pid_ns() can hit ns == NULL. This task_struct can't
> go away, but task_active_pid_ns(task) is NULL if release_task(task)
> was already called. Alternatively we could change get_pid_ns(ns) to
> check ns != NULL, but it seems that other callers are fine.

get_pid_ns already has a ns == NULL check, so no code changes should be
needed.

Eric

>
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>
>
> --- x/kernel/pid_namespace.c
> +++ x/kernel/pid_namespace.c
> @@ -318,7 +318,9 @@ static void *pidns_get(struct task_struct *task)
>  	struct pid_namespace *ns;
>  
>  	rcu_read_lock();
> -	ns = get_pid_ns(task_active_pid_ns(task));
> +	ns = task_active_pid_ns(task);
> +	if (ns)
> +		get_pid_ns(ns);
>  	rcu_read_unlock();
>  
>  	return ns;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/