On a stock install of RHEL5, I install cyrus-sasl and nss_ldap.  I then
configure /etc/ldap.conf and the relavent files in /etc/pam.d.  saslauthd is
then unable to process authentication events through pam.  The logged events are:

kernel: audit(1185169532.791:24): avc:  denied  { read } for  pid=2055
comm="saslauthd" name="imap" dev=xvda1 ino=2162692
scontext=root:system_r:saslauthd_t:s0 tcontext=root:object_r:tmp_t:s0 tclass=file
kernel: audit(1185172800.708:42): avc:  denied  { getattr } for  pid=5906
comm="saslauthd" name="imap" dev=xvda1 ino=2162691
scontext=root:system_r:saslauthd_t:s0 tcontext=root:object_r:tmp_t:s0 tclass=file

I am able to work around the problem by doing 'allow saslauthd_t tmp_t:file {
getattr read };'