Re: [PATCH v8 00/41] Richacls

From: J. Bruce Fields
Date: Mon Sep 28 2015 - 13:46:56 EST

On Mon, Sep 28, 2015 at 07:10:06PM +0200, Andreas GrÃnbacher wrote:
> 2015-09-28 18:35 GMT+02:00 J. Bruce Fields <bfields@xxxxxxxxxxxx>:
> > On Mon, Sep 28, 2015 at 12:08:51AM +0200, Andreas Gruenbacher wrote:
> >> Open issues in nfs:
> >>
> >> * When a user or group name cannot be mapped, nfs's idmapper always maps it
> >> to nobody. That's good enough for mapping the file owner and owning
> >> group, but not for identifiers in acls. For now, to get the nfs richacl
> >> support somewhat working, I'm explicitly checking if mapping has resulted
> >> in uid/gid 99 in the kernel.
> >>
> >> * When the nfs server replies with NFS4ERR_BADNAME for any user or group
> >> name lookup, the client will stop sending numeric uids and gids to the
> >> server even when the lookup wasn't numeric. From then on, the client
> >> will translate uids and gids that have no mapping to the string "nobody",
> >> and the server will reject them. This problem is not specific to acls.
> >
> > Do you have fixes in mind for these two issues?
> I'm not sure how to best fix the idmapper problem, with backwards
> compatibility and all.

I haven't looked at the current nfsidmap interface.... So it's
completely lacking any way to communicate failure?

> The second problem shouldn't be too hard to fix.

Is it enough to turn off the failover in the case there's no possibility
it could have been caused by a numeric id?

If any user can set ACLs with arbitrary strings as names, then we'd be
giving any user unprivileged user the ability to turn off numeric
idmapping, so I think we need to fix that.

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