Re: [PATCH 3/1] xfstests: generic/062: Do not run on newer kernels
From: Vivek Goyal
Date: Fri Sep 03 2021 - 11:43:20 EST
On Fri, Sep 03, 2021 at 10:42:34AM -0400, Bruce Fields wrote:
> Well, we could also look at supporting trusted.* xattrs over NFS. I
> don't know much about them, but it looks like it wouldn't be a lot of
> work to specify, especially now that we've already got user xattrs?
> We'd just write a new internet draft that refers to the existing
> user.* xattr draft for most of the details.
Will be nice if we can support trusted.* xattrs on NFS.
> On Fri, Sep 3, 2021 at 2:56 AM Andreas Gruenbacher <agruenba@xxxxxxxxxx> wrote:
> > On Fri, Sep 3, 2021 at 8:31 AM Andreas Gruenbacher <agruenba@xxxxxxxxxx> wrote:
> > > On Thu, Sep 2, 2021 at 5:47 PM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> > > > xfstests: generic/062: Do not run on newer kernels
> > > >
> > > > This test has been written with assumption that setting user.* xattrs will
> > > > fail on symlink and special files. When newer kernels support setting
> > > > user.* xattrs on symlink and special files, this test starts failing.
> > >
> > > It's actually a good thing that this test case triggers for the kernel
> > > change you're proposing; that change should never be merged. The
> > > user.* namespace is meant for data with the same access permissions as
> > > the file data, and it has been for many years. We may have
> > > applications that assume the existing behavior. In addition, this
> > > change would create backwards compatibility problems for things like
> > > backups.
> > >
> > > I'm not convinced that what you're actually proposing (mapping
> > > security.selinux to a different attribute name) actually makes sense,
> > > but that's a question for the selinux folks to decide. Mapping it to a
> > > user.* attribute is definitely wrong though. The modified behavior
> > > would affect anybody, not only users of selinux and/or virtiofs. If
> > > mapping attribute names is actually the right approach, then you need
> > > to look at trusted.* xattrs, which exist specifically for this kind of
> > > purpose. You've noted that trusted.* xattrs aren't supported over nfs.
> > > That's unfortunate, but not an acceptable excuse for messing up user.*
> > > xattrs.
> > Another possibility would be to make selinux use a different
> > security.* attribute for this nested selinux case. That way, the
> > "host" selinux would retain some control over the labels the "guest"
> > uses.
> > Thanks,
> > Andreas