Re: [gentoo-user] ssh-agent

[Mick]

On Monday 12 February 2007 23:26, Justin Patrin wrote:
> On 11/21/06, Jorge Almeida <jalmeida@××××××××××××.pt> wrote:
> > On Tue, 21 Nov 2006, Mick wrote:
> > >>> They are only stored in locked memory; they are never on disk
> > >>> unencrypted. Anyone that can read locked memory can access them, but
> > >>> this is very few users/processes on Linux -- and besides those same
> > >>> users will be able to read the key as you authenticate even if you
> > >>> don't use ssh-agent, as long as they time things right.
> > >>
> > >> OK, this sounds better! I posted to the gnupg-users, asking a similar
> > >> question about gpg-agent. I guess gpg-agent works the same way.
> > >
> > > Please post back your findings!
> >
> > Well, no responses yet in the gnupg-users list, so there are no findings
> > to post!  (Let's wait at least a few hours :))
> >
> > > What happens to the /tmp/ directory & socket file after the user logs
> > > out? Does it get deleted by the ssh-agent shutdown script?
> >
> > I didn't start using ssh-agent yet, but I tested it from the command
> > line and the directory was removed when I killed the ssh-agent process.
> >
> > > I am asking this because I seem to continuously accumulate a load of
> > > gpg-agent directories and socket files into my /tmp.  Unless of course
> > > gpg-agent works
> >
> > I suppose that has to do with the agent(s) working as daemons? I don't
> > like that kind of setup. This is what I intend to (try to) do:
> >
> > - One fixed socket, in some dedicated directory (no /tmp, no random name
> >    for the socket)
> > - The socket name as a fixed env variable, set in the shell config files
> > - Hence, no need to eval, etc
> > - No daemon (i.e. no backgrounding). Just a service supervised by
> >    daemontools. Logs go to a directory of my choosing and if the agent
> >    dies, it is ressurrected, and the socket (with the same name) is
> >    recreated (of course, keys must be added, then)
> > - A perl script to interact with the service, just in case.
> >
> > I think this is not difficult to do, unless I grossly misunderstood
> > something essential. (Comments, anyone?) I just don't see the need to
> > run the agent as subordinate of an X session or whatever (please someone
> > correct me if I'm wrong!) And if I don't want the service running when
> > I'm not logged in, I could bring it down with the perl script (in
> > ~/.bash_logout, maybe?)
> > For gpg-agent, I'm not so sure, but I hope it can be done too.
> >
> > > on a different principle all together.  My start up & shutdown scripts
> > > are in /etc/X11/Sessions/fluxbox.  Are they correct for this task?
> > > ================================================
> > > eval "$(gpg-agent --daemon)"
> > > /usr/bin/startfluxbox
> > > kill `echo ${GPG_AGENT_INFO} | cut -d ':' -f 2`
> > > ================================================
> > >
> > > Or should I have another line to 'rm -Rf /tmp/gpg-*'
>
> ssh-agent /bin/sh
>
> When you exit the shell, ssh-agent exits too (after cleaning up).
> Running the agent as a daemon means you have to tell it when to shut
> down as well (how would it know when to stop?).

Thanks Justin, the ssh-agent may clean up after its own lock-files, but the 
gpg-agent doesn't.  At least not when using my script above.  My /tmp is full 
of gpg-xxxx lock-files, which in the absence of a better solution I manually 
delete every now and then.
-- 
Regards,
Mick