linux-kernel - Re: [RFC][PATCH] ps command race fix take 4 [1/4] callback subroutine

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] [day] [month] [year] [list]

Date:	Tue, 5 Sep 2006 10:41:56 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	ebiederm@...ssion.com (Eric W. Biederman)
Cc:	linux-kernel@...r.kernel.org, akpm@...l.org, ak@...e.de
Subject: Re: [RFC][PATCH] ps command race fix take 4 [1/4] callback
 subroutine

On Mon, 04 Sep 2006 16:48:43 -0600
ebiederm@...ssion.com (Eric W. Biederman) wrote:

> KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> writes:
> 
> > Updated some dirty codes. maybe easier to read than previous one.
> >
> > This ps command fix (proc_pid_readdir() fix) fixes the problem by
> >
> > - attach a callback for updating pointer from file descriptor to a task invoked
> >   at release_task()
> > - no additional global lock is required.
> > - walk through all and only task structs which is thread group leader.
> >
> > *Bad* point is adding additonal (small) lock and callback in exit path.
> With an unbounded callback chain length influenced by user space.
> 
yes. 1000 ps process will add 1000 chains. 1000 callbacks are called if a task is
removed while 1000 ps task points to it.


-Kame

-
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/