On Mon, Aug 04, 2008 at 02:20:10AM -0700, Ralph Shumaker wrote:

The manuals have enlightened me on some things, but confused me on many others. I want rafael to have full sudo access, but only if he is at this keyboard I am using right now, regardless of whatever IPv4 (or IPv6) address is currently assigned to eth0 by my DSL ISP. I don't know if the IPv6 address ever changes. I haven't paid attention. If it doesn't, perhaps I can somehow use that to lock it in?

This is not what the Host field in the sudoers file is for.  This is so
that multiple machines can share a single sudoers file, and you can
restrict a particular user to performing sudo on certain machines.  But,
it doesn't care how that user logged in.

What is an acceptable method for that user to log in?  Do you want them
to have to be logged into a terminal console, or is an X connection
acceptable.

The thing is that there is very little difference in the environment
between a user logged in locally and one logged in remotely, especially
if the local user is using X.  This is part of what makes Unix/Linux so
useful.

You can set 'requiretty' which will at least require the remote user to
have acquired a tty.  This doesn't completly solve things, although it
would catch simple cases of a remote user exploit that wasn't a login.

You could check ownership of /dev/console, but I'm not sure how you
could do that in sudo.  Well, one ugly way would be to only allow the
user to sudo 'wrapper' and have the wrapper program check ownership of
console and then either deny it or execute the command.

Do you plan on not allowing remote logins for this user?

David


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