/proc mounted in chroot breaks su

[Steve Brueckner]

Hello, I've got what I think might be a real zinger for y'all:

I've got a chrooted environment that's pretty much a duplicate of my primary
file system (I copied almost everything into it).  I've also got /proc
mounted in the chroot environment.  Yes, I realize what a security risk that
is, but I need the Java to work in the chrooted environment, and that
requires access to /proc for heap and thread information.  I'm using FC3
with SELinux enabled but in permissive mode (targeted policy).  Since it's
in permissive mode, I don't think the SELinux is coming into play here.

My problem is that I can't drop privilege once I'm in the chrooted
environment unless I umount /proc from the chrooted environment.  For
example:

# /usr/sbin/chroot /chrootdir
# su steve
Password: (I enter it correctly)
could not open session
#

But if I umount /chrootdir/proc I get this:

# /usr/sbin/chroot /chrootdir
# su steve
$

Note that in the first case, su prompts for my password and in the second
case it doesn't.

Outside of the chrooted environment, su behaves (correctly) just like su
inside the chrooted environment with /chrootdir/proc unmounted.  This is an
apparent paradox: outside the chrooted environment su has access to /proc
and behaves correctly, but inside the chrooted environment su behaves
incorrectly when it has access to /proc, and only works when its access to
/proc is removed!

Any thoughts, ideas, or solutions are welcome.  Thanks.

 - Steve