Re: [GENERAL] pam-linux, /etc/shadow : HOW-TO

On Wed, 21 May 2003, Shridhar Daithankar wrote:

> Hi,
>
> could you please make a smal writeup on this so that it canbe posted on
> techdocs. A small HOWTO.. That would help a lot of people.
>
> Shridhar

sure. html?

-a

>
> On 20 May 2003 at 19:13, ahoward wrote:
>
> >
> > note: i'm no sysad, nor do i even pretend to understand pam, the linux kernel,
> > or postgresql, but this setup is a safe, working, postgresql/linux/pam setup.
> >
> > 0) configure postgresql for pam, for example
> >
> > [root(at)omega tmp]# grep pam /usr/local/pgsql/data/pg_hba.conf
> > host all all 137.75.0.0 255.255.0.0 pam
> >
> > 1) create a /etc/pam.d/postgresql entry, here's how i did mine
> >
> > [root(at)omega tmp]# cp /etc/pam.d/passwd /etc/pam.d/postgresql
> >
> > i don't know if it's the best setup, but it works! mine looks like this
> >
> > [root(at)omega tmp]# cat /etc/pam.d/postgresql
> > #%PAM-1.0
> > auth required /lib/security/pam_stack.so service=system-auth
> > account required /lib/security/pam_stack.so service=system-auth
> > password required /lib/security/pam_stack.so service=system-auth
> >
> > 2) create a shadow group which will be used for user's needing read-access to
> > /etc/shadow, and add postgres (or whatever user the postmaster runs as) to
> > this entry. i used vi to add this entry to /etc/group
> >
> > [root(at)omega tmp]# grep shadow /etc/group
> > shadow:*:4002:root,postgres
> >
> > root probably does not *need* to be added.
> >
> > note the '*' v.s. an 'x' in the password field. if you place an 'x' there
> > you will also have to set up /etc/gshadow - i did not want to do this. if
> > you don't set up /etc/gshadow pam will NOT work if an 'x' is in the password
> > field - at least with my linux system.
> >
> > 3) make /etc/shadow group shadow
> >
> > [root(at)omega tmp]# chgrp shadow /etc/shadow
> >
> > 4) chmod 0440 /etc/shadow
> >
> >
> > essentially, pam will not work with postgres since the daemon needs at some
> > point, no matter how many library calls deep, to open and read /etc/shadow
> > (assuming this is how your system is using pam). you must have some solution
> > which allows postgres, but not everyone, to read /etc/shadow. others probably
> > exist.
> >
> > -a
> >
> > --
> > ====================================
> > | Ara Howard
> > | NOAA Forecast Systems Laboratory
> > | Information and Technology Services
> > | Data Systems Group
> > | R/FST 325 Broadway
> > | Boulder, CO 80305-3328
> > | Email: ara(dot)t(dot)howard(at)fsl(dot)noaa(dot)gov
> > | Phone: 303-497-7238
> > | Fax: 303-497-7259
> > ====================================
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 4: Don't 'kill -9' the postmaster
>
>
>

--
====================================
| Ara Howard
| NOAA Forecast Systems Laboratory
| Information and Technology Services
| Data Systems Group
| R/FST 325 Broadway
| Boulder, CO 80305-3328
| Email: ara(dot)t(dot)howard(at)fsl(dot)noaa(dot)gov
| Phone: 303-497-7238
| Fax: 303-497-7259
====================================