[CentOS] nsswitch.conf, ldap, local groups problem

Craig White craigwhite at azapple.com
Wed Aug 27 21:11:44 UTC 2008


On Wed, 2008-08-27 at 17:07 -0400, Mark Hennessy wrote:
> Quoting Craig White <craigwhite at azapple.com>:
> 
> > On Wed, 2008-08-27 at 14:53 -0400, Mark Hennessy wrote:
> >> Quoting Craig White <craigwhite at azapple.com>:
> >>
> >> > On Wed, 2008-08-27 at 12:34 -0400, Mark Hennessy wrote:
> >> >> I'm using CentOS 5.0,5.1, and 5.2 on several systems where I'm seeing
> >> >> this problem.
> >> >>
> >> >> Hello, I'm seeing a weird problem that perhaps someone has run into
> >> >> with groups.
> >> >>
> >> >> First, a little background.
> >> >> I was made aware of a problem with CentOS 5 where if the nscd password
> >> >> cache is clear and
> >> >> someone tries to log in if there is no network connection with an LDAP
> >> >> account that it
> >> >> just hangs.  Even worse, if the machine is rebooted and it continues
> >> >> to have no network
> >> >> connection, even root login doesn't work.  I messed around with
> >> >> nsswitch.conf to fix this
> >> >> problem.
> >> >>
> >> >> I altered these lines as so:
> >> >> passwd:     files [!NOTFOUND=return] ldap
> >> >> shadow:     files [!NOTFOUND=return] ldap
> >> >> group:      files [!NOTFOUND=return] ldap
> >> >>
> >> >> and the problem seemed to go away.
> >> >>
> >> >> But now, here's the weird stuff:
> >> >> I have defined in my local /etc/groups file this line:
> >> >> group1:x:100:apache
> >> >> group2:x:101:apache
> >> >>
> >> >> 'getent group groupname' shows the right info:
> >> >> # getent group group1
> >> >> group1:x:100:apache
> >> >>
> >> >> # sudo -u apache bash
> >> >> $ groups
> >> >> apache
> >> >>
> >> >> I revert back to my old config:
> >> >> # sudo -u apache bash
> >> >> $ groups
> >> >> apache group1 group2
> >> >>
> >> >> Also, something else that's interesting. If I do this:
> >> >> passwd:     files [!NOTFOUND=return] ldap
> >> >> shadow:     files [!NOTFOUND=return] ldap
> >> >> group:      ldap [NOTFOUND=continue] files
> >> >>
> >> >> and reboot, udev segfaults and the system freezes up after a few
> >> >> more seconds.
> >> >> Starting udev: /sbin/start_udev: line 43:   519 Segmentation fault
> >> >>   "$@" $ARGS
> >> >> /sbin/start_udev: line 201:   523 Segmentation fault      /sbin/udevd -d
> >> >> Wait timeout. Will continue in the background.[FAILED]
> >> >>
> >> >> Any advice?
> >> > ----
> >> > Try putting this at the bottom of /etc/ldap.conf
> >> >
> >> > timelimit 30
> >> > bind_timelimit 30
> >> > bind_policy soft
> >> > nss_initgroups_ignoreusers root,ldap
> >> >
> >> > I wouldn't recommend the changes that you have in nsswitch.conf
> >>
> >> Unfortunately, that doesn't work either.
> >> I made the changes, shut down the machine and started it without
> >> networking, and here's what happens:
> >>
> >> login: root
> >> Password:
> >>
> >> login:
> >>
> >> login pukes and init starts it again.
> > ----
> > you shouldn't need to restart but if you can't login as root, you
> > probably still have something messed up in /etc/nsswitch.conf or may
> > have messed up /etc/passwd | /etc/shadow
> >
> > can you login as a user and su - to root?
> >
> > if not, it probably would be best to boot to runlevel 1 and
> > edit /etc/nsswitch.conf so it has this...
> >
> > passwd:     files ldap
> > shadow:     files ldap
> > group:      files ldap
> >
> > and remove the NOTFOUND entries
> 
> Yes, done.
> Without networking, still the login failure trouble.
> 
> With networking, no trouble at all, but with those timeouts of 30  
> seconds and without those changes to nsswitch.conf, it takes a while  
> for the first root login to succeed even though it is using local auth.
----
do you have this line in /etc/pam.d/system-auth

account     sufficient    pam_localuser.so

???

What does your /etc/pam.d/system-auth look like?

Craig



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