Re: [PATCH] Reserve N process to root

[David Newall <david@davidnewall.com>]

Gustavo Chain wrote:
> El Wed, 10 Oct 2007 15:14:06 +0930
> David Newall <david@davidnewall.com> escribió:
>   
>> Gustavo Chain wrote:
>>     
>>> El Wed, 10 Oct 2007 11:19:27 +0930
>>> David Newall <david@davidnewall.com> escribió:
>>>   
>>>       
>>>> Gustavo Chain wrote:
>>>>     
>>>>         
>>>>> I think it's necessary to reserve some pids to the super user.
>>>>> 5 must be sufficient.
>>>>>       
>>>>>           
>>>> Why?  (Sorry if I missed something.)
>>>>     
>>>>         
>>> ¿ To prevent a posible DoS ?
>>>   
>>>       
>> That was what I thought you had in mind; it protects from some kind
>> of fork bomb, right?  But it doesn't seem useful unless you guarantee 
>> having a process already running (with CAP_SYS_ADMIN) *before* the
>> bomb goes off.
>>     
>
> Not really, because fork bomb will never reach maximum pid possible.
> And root will always have a "slot" to kill desired processes.
>   

This is like pulling teeth: painful.

I don't think you have satisfactorily explained why it's necessary.  "To 
prevent a possible DoS" isn't sufficient by itself.  I think you should 
explain the scenarios you have in mind.