lkml.org 
[lkml]   [2000]   [Oct]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: PIDs limited to 15 significant bits
Date
Andries Brouwer writes:
> On Fri, Sep 29, 2000 at 03:57:10PM -0400, Albert D. Cahalan wrote:

>>> My machines regularly see 6- or 7-digit PIDs.
>
>> Oh, the horror!
>>
>> Consider, do you like to type "kill 1234567890" more than
>> a simple "kill 1234"?
>
> Hmm. I double click on the ps output and single click to paste.
> The number of digits does not play a role.

I have a real VT510 terminal w/o a mouse, but OK...
I still don't like to read and compare such numbers.

>> What do you think of "ps -efj" on a standard 80x24 screen?
>
> I never give such commands, but just tried:
>
> aeb 119876 1 426 236 0 23:32 tty1 00:00:00 xterm
> aeb 119877 119876 119877 119877 0 23:32 pts/9 00:00:00 -bash
> aeb 119884 119877 119884 119877 0 23:33 pts/9 00:00:00 ps -efj
>
> as you see, the ps program here fails to align the columns,
> but otherwise all is well.

How are you going to like the output after some more uptime?
The record is around 1200 days I think. With a faster machine
doing a lot of work, you could just about lose the CMD column.

>>> [The patch is available. There are a few security advantages.
>>
>> There should not be any significant security advantages.
>> One can easily wrap/predict in a 31-bit space.
>
> There are a few weaknesses that can be exploited using a wraparound.
> With 100 processes/sec that takes 497 days with a 32-bit pid
> and 5 minutes with a 16-bit pid.

David Miller once posted a forks/second rate for SPARC that was
many thousands... these days, once might wrap once per second.

So the 31-bit space won't help you much. If you really want
this kind of security, you should make me an offer for my old PC.
I'll even pop out the OverDrive, getting you down to 25 MHz.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 12:39    [W:0.086 / U:2.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site