Re: [PATCH 7/9] syslog_ns: implement function for creating syslog ns

[Gu Zheng <guz.fnst-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>]

On 07/30/2013 11:39 AM, Rui Xiang wrote:

> On 2013/7/29 18:25, Gu Zheng wrote:
>> Hi Rui,
>>
>> On 07/29/2013 10:31 AM, Rui Xiang wrote:
>>
>>> Add create_syslog_ns function to create a new ns. We
>>> must create a user_ns before create a new syslog ns.
>>> And then tie the new syslog_ns to current user_ns
>>> instead of original syslog_ns which comes from
>>> parent user_ns.
> 
> ...
> 
>>> diff --git a/kernel/printk.c b/kernel/printk.c
>>> index fd2d600..6b561db 100644
>>> --- a/kernel/printk.c
>>> +++ b/kernel/printk.c
>>> @@ -384,6 +384,10 @@ static int check_syslog_permissions(int type, bool from_file,
>>>  		|| type == SYSLOG_ACTION_CONSOLE_LEVEL)
>>>  		ns = &init_syslog_ns;
>>>  
>>> +	/* create a new syslog ns */
>>> +	if (type == SYSLOG_ACTION_NEW_NS)
>>> +		return 0;
>>> +
>>
>> Don't we need further permission or caps check here? Return success directly seems sloppy. 
>>
> CAP_SYSLOG is checked in create_syslog_ns, so I think we can return 0 temporarily.

If so, why not move the check here? IMO, permission checking is the earlier the better,
what's your opinion?

Regards,
Gu

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