linux-kernel - Re: [PATCH] namespace:unmount pid_namespace's proc_mnt when copy_net

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 for Android: free password hash cracker in your pocket

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

Message-ID: <87wqy4fkqx.fsf@xmission.com>
Date:	Fri, 02 Nov 2012 01:54:14 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Gao feng <gaofeng@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org, containers@...ts.linux-foundation.org
Subject: Re: [PATCH] namespace:unmount pid_namespace's proc_mnt when copy_net_ns failed

Gao feng <gaofeng@...fujitsu.com> writes:

> 于 2012年11月02日 15:02, Eric W. Biederman 写道:
>> Gao feng <gaofeng@...fujitsu.com> writes:
>> 
>>> we should call pid_ns_release_proc to unmount pid_namespace's
>>> proc_mnt when copy_net_ns failed in function create_new_namespaces.
>>>
>>> otherwise,the proc_mnt will not be freed and because the super_block
>>> of proc_mnt also add the reference of the pid_namespace,so this
>>> pid_namespace will never be released too.
>> 
>> Ouch!
>> 
>> Have you encountered this failure in practice or is this just from
>> review?
>
> I add some printk in pid_ns_release_proc,it's not called in above case.
> when copy_net_ns failed,this pid_namespace is not used by any task,
> so proc_flush_task can't call pid_ns_release_proc to umount this pidns->proc_mnt.
> it's the only chance we can unmount this pindns->proc_mnt.
>
> With this patch,everything runs well.

I have reviewed the code and I don't doubt that this is necessary.

What caused you to look into this failure?  Is there some semi-practical
real world case that someone is hitting?

Eric
--
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/