I was coming from the other perspective that perhaps the permissions
were 000, not 600.  As it turns out, Betsie wasn't prefacing her command
with "sudo" which was why it wasn't working.

And, I agree with your warnings about giving access to CP commands.  If
you're not careful which ones can be executed, then the whole guest is
at risk.  If the guest has more than class G privileges, it would put VM
itself at risk.  Hopefully no one is doing that, and combining the two
setups.


Mark Post

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Martin Schwidefsky
Sent: Friday, October 20, 2006 4:45 AM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: CP commands through a Web interface

On Thu, 2006-10-19 at 16:57 -0400, Post, Mark K wrote:
> What are the permissions on /dev/vmcp?

Even if you set the permission of /dev/vmcp to allow normal users to
access the device, it won't allow the user to execute cp commands. There
is an additional CAP_SYS_ADMIN check in the vmcp_open function.
The reason is that a user that can execute cp commands owns the machine,
with strategically placed vmcp "STORE <addr> <data>" calls you change
any code in the kernel. So you better make sure that nobody who is not
trusted can get control to issue arbitrary cp commands. That is
especially true if you use vmpc in a web interface. It sounds like a
very dangerous thing to do.

--
blue skies,
  Martin.

Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH

"Reality continues to ruin my life." - Calvin.

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