Vulnerability Development mailing list archives
Re: luser beeing able to kill random root owned procs (linux 2.2.20) ?
From: Samu <samu () linuxasylum net>
Date: Sat, 10 Nov 2001 18:11:07 +0100
On Fri, Nov 09, 2001 at 04:55:52PM -0800, rpc wrote:
On Wed, 1 Jan 1997, Ralf Dreibrodt wrote:Hi,while running "vi `perl -e 'print "." x 90000000'`" on a 2.2.20 linux kernel as a normal user, I've noticed: forsaken:~$ dmesg VM: killing process snmpd forsaken:~$ uname -rs Linux 2.2.20 snmpd was running as root (this machine has 64MBytes of RAM)the user is not allowed to kill a process owned by root, the user is allowed to use all RAM (and probably swap). you can test whether he is allowed to and what will happen, when you execute something like this: while true; do temp=$(echo temp$temp$temp$temp); doneNo, this is an artifact of Rik van Riel's OOM (out of memory) Kill code of the linux VM. When system resources are low, a process is chosen with a 'badness' algorithm (oom_kill.c in the kernel source tree).
it always a good idea to set system limit per users (ulimit) which lets you to avoid DOS from local user: for example there was this beautifoul piece of code on to an attachment of a guy ... :(){:|:&};: which cause to gain all system resources and freeze your machine ... . with ulimit you can avoid problems depended from ppl trying to catch all system resources and so avoid that problem you specify. Samuele -- Samuele Tonon <samu () linuxasylum net> http://www.linuxasylum.net/~samu/ Acid -- better living through chemistry. Timothy Leary
Current thread:
- Re: luser beeing able to kill random root owned procs (linux 2.2.20) ? Ralf Dreibrodt (Nov 09)
- Re: luser beeing able to kill random root owned procs (linux 2.2.20) ? rpc (Nov 09)
- Re: luser beeing able to kill random root owned procs (linux 2.2.20) ? Samu (Nov 10)
- Re: luser beeing able to kill random root owned procs (linux 2.2.20) ? rpc (Nov 09)