From: Herbert Poetzl (herbert_at_13thfloor.at)
Date: Mon 02 May 2005 - 14:02:23 BST
On Mon, May 02, 2005 at 11:11:11AM +0200, Nicolas Costes wrote:
> Le Vendredi 29 Avril 2005 21:53, Oliver Dietz a écrit :
> > ok, lets do some brainstorming (comment: i'm no vserver specialist nor
> > can i write programs on linux):
> > [OK] Checking proc-fs                                          [WARN]
> > found kmem-entry [...]
> 
> Talking about that, I checked /proc on one of my vservers... Is this line 
> a good thing ? Is it a potential security issue ?
usually (i.e. after vprocunhide) you have something like:
$ chcontext --ctx 100 ls /proc/
New security context is 100
1	 devices      iomem    loadavg	mounts	slabinfo  sysvipc
85	 execdomains  ioports  locks	net	stat	  tty
cmdline  filesystems  kcore    meminfo	pci	swaps	  uptime
cpuinfo  interrupts   kmsg     misc	self	sys	  version
which looks a little _insecure_ at first glance, but
if you look a little closer ...
$ chcontext --ctx 100 --secure wc /proc/kcore 
New security context is 100
wc: /proc/kcore: Operation not permitted
which should be sufficient, of course, you can always
hide that entry too, given that your userspace doesn't
look for it ...
HTH,
Herbert
> # ls -l /proc
> -r--------   1 root      root      939528192 mai  2 11:04 kcore
> 
> Note: I have 1Gb ram on this box...
> 
> -- 
>   ,,
>  (°>   Nicolas Costes
>  /|\   IUT de La Roche / Yon
> ( ^ )  Clé publique: http://www.keyserver.net/
>  ^ ^   Musique libre: http://www.magnatune.com/
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