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Date:      Sun, 14 Oct 2001 22:58:27 -0400 (EDT)
From:      Francisco Reyes <lists@natserv.com>
To:        <cjclark@alum.mit.edu>
Cc:        FreeBSD Questions List <questions@FreeBSD.ORG>
Subject:   Re: Automating ssh connections so only one command would run.
Message-ID:  <20011014225334.V18306-100000@zoraida.natserv.net>
In-Reply-To: <20011012222025.I6274@blossom.cjclark.org>

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> > >it is trivial to slip commands through scp(1),
> > >$ scp 'remote:somefile;touch /tmp/scp_test' .
> > > And check for /tmp/scp_test on the remote machine.
> > I don't see how this is a security problem. Could you explain?
>
> I presume you want to limit people to scp(1) so they do not have full
> shell access; they can't execute arbitrary commands on the remote
> machine. With scp(1), you can do,
>
>   $ cat > command.sh <<EOF
>   > exec > command.out 2>&1
>   > <put your arbitrary commands here>
>   > EOF
>   $ scp command.sh remote:
>   $ scp 'remote:nonexistent; /bin/sh command.sh' .
>   $ scp remote:command.out .
>   $ more command.out

I just did what you wrote above. All a person would be able to do is to
copy the command.sh file/command to the other machine. If I could limit
their ability to only run scp and not ssh there would be no harm (in my
setup) just by been able to copy arbitrary files. Of course I still need
to have a quota so they don't override the space on the other machine, but
that is not all too much trouble.

> > Automating scp may not be the most secure way to copy data, but is there a
> > better way?
> scp = ssh = shell access. But I may have misunderstood what you are
> trying to achieve.

I am just trying to copy 2 files every day from one machine to another.


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