Re: fattr4_hidden and fattr4_system r/w attributes in Linux NFSD?

[Sebastian Feld]

Yearly reminder that this is still not fixed.

Sebi

On Tue, Jun 17, 2025 at 9:59 AM Sebastian Feld
<sebastian.n.feld@xxxxxxxxx> wrote:
>
> On Tue, Apr 29, 2025 at 3:45 PM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
> >
> > On 4/29/25 9:10 AM, Sebastian Feld wrote:
> > > On Mon, Apr 28, 2025 at 4:15 PM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
> > >>
> > >> Hi Sebastian -
> > >>
> > >> On 4/28/25 7:06 AM, Sebastian Feld wrote:
> > >>> I've been debating with Opentext support about their Windows NFS4.0
> > >>> client about a problem that the Windows attributes HIDDEN and SYSTEM
> > >>> work with a Solaris NFSD, but not with a Linux NFSD.
> > >>>
> > >>> Their support said it's a known bug in LInux NFSD that "fattr4_hidden
> > >>> and fattr4_system, specified in RFC 3530, are broken in Linux NFSD".
> > >>
> > >> RFC 7530 updates and replaces RFC 3530.
> > >>
> > >> Section 5.7 lists "hidden" and "system" as RECOMMENDED attributes,
> > >> meaning that NFSv4 servers are not required to implement them.
> > >>
> > >> So that tells me that both the Solaris NFS server and the Linux NFS
> > >> server are spec compliant in this regard. This is NOTABUG, but rather it
> > >> is a server implementation choice that is permitted by RFC.
> > >>
> > >> It is more correct to say that the Linux NFS server does not currently
> > >> implement either of these attributes. The reason is that native Linux
> > >> file systems do not support these attributes, and I believe that neither
> > >> does the Linux VFS. So there is nowhere to store these, and no way to
> > >> access them in filesystems (such as the Linux port of NTFS) that do
> > >> implement them.
> > >>
> > >> We want to have a facility that can be used by native applications
> > >> (such as Wine), Samba, and NFSD. So implementing side-car storage
> > >> for such attributes that only NFSD can see and use is not really
> > >> desirable.
> > >
> > > I did a bit of digging, that debate started in 2002.
> > >
> > > 23 years later, nothing happened. No Solution.
> > > Very depressing.
> >
> > It's a hard problem.
> >
> > Focus on the recent work. It appears to be promising and there have
> > been few objections to it.
>
> Do you have any reference to that work? Are there status updates?
>
> Sebi
> --
> Sebastian Feld - IT security consultant



-- 
Sebi
-- 
Sebastian Feld - IT security consultant