pam-0.77-66.13 errata breaks subversion

[Jay Levitt]

I'm running RHEL AS4 for 32-bit x86. When I install the pam-0.77-66.13 
10/26/05 errata (for RHSA-2005:805), I'm no longer able to use pam_unix 
to authenticate mod_dav_svn.  I get the following error in 
/var/log/messages when attempting to login with a subversion client:

Nov 15 19:56:25 dev httpd(pam_unix)[31001]: authentication failure; 
logname= uid=48 euid=48 tty= ruser= rhost=  user=jay

(UID 48 is the apache login.)  Rolling back to pam-0.77-66.11 solves the 
problem.  I have no problem using pam_unix to authenticate regular web 
directories, only subversion repositories, which seems like a good clue.

How can I tell if this is a bug in the errata, or a bug in the way 
mod_dav_svn works?  Maybe it doesn't ask for the right privileges, but 
the former pam bug was letting it get away with that?  Unfortunately, 
we're an academic install, so I can't report this to Red Hat via support 
channels.

I'm running Apache httpd 2.0.54, installed from source.  Snippets of my 
httpd.conf:

..the regular web site, which works fine...

<Directory "/srv/www/htdocs/my.site.example.com">
        Options +Indexes
        IndexIgnore ..

        SSLRequireSSL
        AuthPAM_Enabled On
        AuthType Basic
        AuthName "Development Intranet"
        Require valid-user
</Directory>

..the subversion repository, which fails as soon as the errata RPM is 
installed...

<VirtualHost *:443>
        ServerName svn.example.com
        CustomLog logs/svn.access.log combined
        SSLEngine On

        # This must be accessible, but is otherwise unused
        DocumentRoot "/srv/www/htdocs/svn-phony"

        <Location /dev/>
                AuthPAM_Enabled on
                AuthType Basic
                AuthName "Developer repository"
                Require group dev
        </Location>

        <Location />
                DAV svn
                SVNParentPath "/srv/svn/"
                SVNPathAuthz off
        </Location>

</VirtualHost>

.. my /etc/pam.d/httpd config ...

#%PAM-1.0
auth       required     /lib/security/pam_unix.so
account    required     /lib/security/pam_unix.so