linux-kernel - Re: [PATCH] kernel: user_namespace: always set the return parameter 'new_cred' when call unshare

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: <52143EE0.3040604@asianux.com>
Date:	Wed, 21 Aug 2013 12:15:28 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	Oleg Nesterov <oleg@...hat.com>
CC:	Serge Hallyn <serge.hallyn@...ntu.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Serge Hallyn <serge.hallyn@...onical.com>,
	Andy Lutomirski <luto@...capital.net>,
	"dhowells@...hat.com" <dhowells@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kernel: user_namespace: always set the return parameter
 'new_cred' when call unshare_userns() successfully.

On 08/20/2013 10:37 PM, Oleg Nesterov wrote:
> On 08/20, Serge Hallyn wrote:
>>
>> Quoting Chen Gang (gang.chen@...anux.com):
>>> When unshare_userns() succeed, recommend to always set the return
>>> parameter which may be used by caller.
>>>
>>> The caller has rights to call it with 'new_cred' uninitialized, if
>>> succeed, the caller can assume the 'new_cred' has been initialized.
>>
>> But the only existing caller (sys_unshare) does in fact initialize it to
>> NULL.  So while this patch does no harm, is it necessary?
> 
> Agreed.
> 
> Plus, with this patch unshare_userns() becomes "inconsistent" compared
> to other unshare_ helpers.
> 
> Oleg.
> 
> 
> 

Hmm... for static functions, they don't need, but for extern functions,
recommend to do so.


For "unshare_ helpers", I find 3 extern functions:

  unshare_files() which already set value.
  unshare_userns() and unshare_nsproxy_namespaces() which not set.

In my opinion, recommend to always set the return parameter when
succeed, for the 2 left extern functions.


Thanks.
-- 
Chen Gang
--
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/