Re: [Vserver] Does adding tty and pty devices to a Vserver compromise security?

From: Bruno <bonbons67_at_internet.lu>
Date: Mon 15 May 2006 - 17:25:21 BST
Message-Id: <200605151825.22032.bonbons67@internet.lu>

On Monday 15 May 2006 06:48, EKC wrote:
> Hello,
>
> I'm running a perl script inside of a linux vserver, and the script
> requires access to tty and pty devices. However /dev/MAKEDEV and mknod
> cannot create pty devices from within a vserver. Therefore I am adding
> pty devices to a vserver by way of the host operating system:
>
> [vserver host] cp -a /dev/tty* /vservers/my_vserver/dev/
> [vserver host] cp -a /dev/pty* /vservers/my_vserver/dev/
>
> Does this compromise the security of the vserver in any way? Is there
> a way to add devices from within a vserver itself?
>
> Thanks in advance,
> EKC
> _______________________________________________
> Vserver mailing list
> Vserver@list.linux-vserver.org
> http://list.linux-vserver.org/mailman/listinfo/vserver

Hello

You could just copy a few tty devices to the guest (from the host), like
tty13, tty14, ... Don't forget to include tty.
The devices under /dev/pts/ are available on demand using ptmx (as used by
ssh)
For the pty devices I don't know

Having a tty inside a guest that's used by the host or another guest can
compromise security. For the devices under /dev/pts/ only those requested by
guest (via opening /dev/ptmx) are also available to guest.

Bruno
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Received on Mon May 15 17:27:42 2006

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