selinux: rhel5 x fedora 14

[Stephen Smalley]

On Thu, 2011-01-13 at 08:14 -0500, Stephen Smalley wrote:
> On Wed, 2011-01-12 at 21:03 +0000, Paul Howarth wrote:
> > On Wed, 12 Jan 2011 13:02:21 -0500
> > Daniel J Walsh <dwalsh at redhat.com> wrote:
> > > On 01/12/2011 06:29 AM, Paulo Cavalcanti wrote:
> > > > Hi,
> > > > 
> > > > I have two HDs on my computer: one with rhel5 5.5 and the other with
> > > > fedora 14.
> > > > Both systems share some directories located in a common /home,
> > > > mainly used by the httpd process.
> > > > 
> > > > The problem is that selinux in fedora 14 uses "unrestricted_u" by
> > > > default for all users, which rel5 does not understand,
> > > > and any file labeled that way is treated as "unlabeled_t" in rhel5.
> > > > 
> > > > I tried to relabel all files in Fedora 14 using "chcon -R -u user_u
> > > > -t user_home_t" , for instance,
> > > > but every new file is still created as "unrestricted_u".
> > > > 
> > > > I know very little about selinux, and I would like to know how to
> > > > force all files in F14 to be user_u,
> > > > but keeping the user owning those files, unrestricted.
> > > > 
> > > > Is that possible? Is there a better solution for not having tons of
> > > > denials in rhel5?
> > > > 
> > > > Thanks.
> > > > 
> > > > -- 
> > > > Paulo Roma Cavalcanti
> > > > LCG - UFRJ
> > > > 
> > > One solution would be to mount with a context on one of the platforms.
> > > 
> > > On RHEL5 mount the users homedir with a context of nfs_t, and set the
> > > boolean to say allow nfs homedirs
> > > 
> > > 
> > > mount -o context="system_u:object_r:nfs_t:s0" /dev/ABC /home
> > > setsebool -P use_nfs_home_dirs 1
> > 
> > What happens with newly-created files whilst booted in RHEL-5 in this
> > case? What will Fedora 14 see them as?
> 
> Not sure what the RHEL-5 kernel does; in modern kernels, it won't set a
> context on disk when creating new files in a filesystem mounted with
> context= and thus they will show up as unlabeled if mounted without a
> context= mount option in Fedora-14.  You could mount it with a context=
> option in both, or run restorecon on it when booting Fedora-14.

Sorry, not "unlabeled" but rather with the default file context for
files without an xattr, which in this case would be file_t.

-- 
Stephen Smalley
National Security Agency