linux-kernel - Re: [Patch 11/21] Track the core generation requests

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]

Message-ID: <20101214160421.GD11400@redhat.com>
Date:	Tue, 14 Dec 2010 17:04:21 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	"Suzuki K. Poulose" <suzuki@...ibm.com>
Cc:	linux-kernel@...r.kernel.org,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>,
	Christoph Hellwig <hch@....de>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Daisuke HATAYAMA <d.hatayama@...fujitsu.com>,
	Andi Kleen <andi@...stfloor.org>,
	Roland McGrath <roland@...hat.com>,
	Amerigo Wang <amwang@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [Patch 11/21] Track the core generation requests

On 12/14, Suzuki K. Poulose wrote:
>
> Concurrent core generation requests
> for the same target process are not allowed.

OK, but

> +static struct core_proc* get_core_proc(struct task_struct *t)
> +{
> +	struct core_proc *cp;
> +
> +	list_for_each_entry(cp, &core_list, list) {
> +		if (cp->task == t->group_leader)
> +			return cp;
> +	}
> +	return NULL;
> +}
> ...
>  static int open_gencore(struct inode *inode, struct file *filp)
>  {
> -	return 0;
> +	struct task_struct *task = get_proc_task(inode);
> +	struct core_proc *cp;
> +	int ret = 0;
> +
> +	if (!task)
> +		return -ENOENT;
> +
> +	mutex_lock(&core_mutex);
> +	cp = get_core_proc(task);
> +	if (cp) {
> +		ret = -EALREADY;

I don't think this can work.

The task can change ->group_leader. This means 2 or more
open_gencore() can succeed if this task execs in between.

Oleg.

--
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/