libnss-ldap/libpam-ldap security issue

[Brian May <bam@snoopy.debian.net>]

Hello,

I posted this to my local mailing list, but got no answer. This is as on 
Debian/etch.

It would appear sudo, a secure program, is reading ldap configuration 
from an insecure file, when pam/nss is configured to use ldap.

brian@sys11:~$ sudo -k
brian@sys11:~$ mv .ldaprc.bad .ldaprc
brian@sys11:~$ sudo /bin/bash
Password:
Segmentation fault
brian@sys11:~$ sudo -k
brian@sys11:~$ mv .ldaprc .ldaprc.bad
brian@sys11:~$ sudo /bin/bash
Password:

brian@sys11:~$ sudo -k
brian@sys11:~$ mv .ldaprc.bad .ldaprc
brian@sys11:~$ ulimit -c unlimited
brian@sys11:~$ sudo /bin/bash
Password:
Segmentation fault

I am not concerned so much about the segfault, that probably has already 
been fixed in the latest software anyway. It would appear a 
non-privileged user can change the defaults used by sudo for LDAP 
authentication, and that would appear to be a bad thing.

Is there anyway to configure the ldap libraries not to read from 
$HOME/.ldaprc?

Brian May