[PATCH] vfs module for VxFS

Abhidnya Joshi Abhidnya_Joshi at symantec.com
Fri Sep 5 03:27:14 MDT 2014

Hi Andrew, Jeremy,

I understand from the discussion that, we can have generic xattr renaming module which anyone can use.
This will also take care of securing these xattrs via samba_private_attr_name().

Please let me know what should be the next step for handling this.

Thanks and regards
Abhidnya Joshi
-----Original Message-----
From: Andrew Bartlett [mailto:abartlet at samba.org] 
Sent: Wednesday, September 03, 2014 6:39 AM
To: Richard Sharpe
Cc: Abhidnya Joshi; Jeremy Allison; samba-technical at samba.org
Subject: Re: [PATCH] vfs module for VxFS

On Tue, 2014-09-02 at 17:16 -0700, Richard Sharpe wrote:
> On Tue, Sep 2, 2014 at 3:36 PM, Andrew Bartlett <abartlet at samba.org> wrote:
> > On Tue, 2014-09-02 at 07:32 -0700, Richard Sharpe wrote:
> >> On Mon, Sep 1, 2014 at 9:24 PM, Andrew Bartlett <abartlet at samba.org> wrote:
> >> > On Mon, 2014-09-01 at 18:44 -0700, Jeremy Allison wrote:
> >> >> On Tue, Sep 02, 2014 at 11:52:49AM +1200, Andrew Bartlett wrote:
> >> >> >
> >> >> > The concern I have is that Samba can permit access to extended 
> >> >> > attributes directly.  You have to ban them in 
> >> >> > samba_private_attr_name() in source3/smbd/trans2.c.
> >>
> >> There is another issue here as well, which is that Samba is not 
> >> flexible enough, IMO, in those cases where the OS or the FS does 
> >> not support separate SYSTEM and USER name spaces.
> >>
> >> Then, all the xattrs have to be collapsed into one name space.
> >>
> >> A trick I have used before is to prefix SAMBA xattrs with something 
> >> like .samba: but that requires more flexibility in the filtering.
> >
> > Richard,
> >
> > Samba uses the different namespaces because they have different 
> > security properties, which is the point I've been trying to make 
> > here.  We certainly could use the user namespace, but the only way 
> > we could do so with confidence in the security of the outcome (in 
> > the general case) is to digitally sign all our 'system' extended attributes.
> Perhaps I did not make myself clear.
> There is at least one OS/FS combination that does not have a separate 
> SECURITY namespace. FreeBSD and ZFS, at least for 8.x and maybe going 
> forward. So, they all have to be mapped to the USER namespace.
> I don't know if that has changed in FBSD 10, or is planned in 11.

For that specific case, if an API for access to the ZFS ACL (NFSv4
compatible) is provided, then we essentially don't need the security.NTACL anyway, as the NFSv4 ACL is close enough.

Andrew Bartlett

Andrew Bartlett
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba

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