Date: Thu, 18 Feb 2016 09:29:26 -0700 From: Ian Lepore <ian@freebsd.org> To: "O. Hartmann" <ohartman@zedat.fu-berlin.de>, RW <rwmaillists@googlemail.com> Cc: freebsd-current@freebsd.org Subject: Re: HELP: Howtwo create a passwd-suitable hash for usage with psswd -H 0? Message-ID: <1455812966.1294.5.camel@freebsd.org> In-Reply-To: <20160218162908.4cf16f6b@freyja.zeit4.iv.bundesimmobilien.de> References: <20160218141624.5f560f2d@freyja.zeit4.iv.bundesimmobilien.de> <20160218145244.0b1e4c94@gumby.homeunix.com> <20160218162908.4cf16f6b@freyja.zeit4.iv.bundesimmobilien.de>
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On Thu, 2016-02-18 at 16:29 +0100, O. Hartmann wrote:
> On Thu, 18 Feb 2016 14:52:44 +0000
> RW <rwmaillists@googlemail.com> wrote:
>
> > On Thu, 18 Feb 2016 14:16:24 +0100
> > O. Hartmann wrote:
> >
> > > Hello out there,
> > >
> > > I run into a problem and digging for a solution didn't work out.
> > >
> > > Problem: I need a string that reflects the hashed password for the
> > > usage with
> > >
> > > passwd -H 0
> >
> > Did you mean -h?
>
> no, I literally mean -H 0, I explain later ...
>
> >
> > > I think the procedure is using
> > >
> > > sha512 -s Password
> > >
> > > and using this output for further processing, but how?
> >
> > It's not as simple as that, password hashes are usually salted and
> > iterated. Salting means that the password is combined with a randomly
> > generated string stored in plaintext, which means that the password
> > doesn't hash to a fixed string.
> >
> > I'm not sure exactly what you are trying to do, but crypt(3) may be of
> > help.
>
> I'm now down to a small C routine utilizing crypt(3). But this is not what I
> intend to have, since I want to use tools from the FBSD base system.
>
> I build images of a small appliance in a secure isolated environment via
> NanoBSD. I do not want to have passwords in the clear around here, but I also
> do not want to type in everytime an image is created, so the idea is to have
> passwords prepared as hashes in a local file/in variables. Therefore, I'm
> inclined to use the option "-H 0" of the pw(1) command to provide an already
> and clean hash (SHA512), which is then stored in /etc/master.passwd.
>
> It is really funny: passwd or pw take passwords via stdin (-h 0 with pw) and
> they "generate" somehow the hashed password and store that in master.password
> - but I didn't find any way to pipe out the writing of the password to the
> standard output from that piece of software. Why? Security concerns I forgot to
> consider?
>
> I found lots of articles and howtos to use pipes producing the required
> password hashes via passwd, chpasswd or pw, but they all have one problem: I
> have to provide somehow the cleartext password in an automated environment.
>
> Maybe there is something missing ...
>
> oh
We use something like this at work (which I don't fully understand, but
it works on freebsd 6.x through 10.x at least)...
echo ${password} | openssl passwd -1 -stdin -salt VerySalty | \
pw -V ${IMAGE_CHROOT_DIR}/etc useradd -n ${username} -H0 $*
I guess for your use you'd capture and save the output of openssl so
you could later feed it back to pw when making images.
-- Ian
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