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Re: [PATCH v8 00/41] Richacls

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2015-09-28 19:46 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>:
> On Mon, Sep 28, 2015 at 07:10:06PM +0200, Andreas Grünbacher wrote:
>> 2015-09-28 18:35 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>:
>> > 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?

Yes, when a user doesn't exist, idmapper maps that to the nobody
uid/gid. That's the failure mode of stat. In the acl case, we do want
to map user and group names to their respective ids where possible (so
that the acl makes sense in the local system context), but we do want
to preserve the original user and group names when there is no such
mapping instead of mapping to the nobody uid/gid.

>> 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?

Yes, I believe that would be enough.

> 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.

The bug can be triggered by unprivileged users with nfs4_setfacl.

Thanks,
Andreas
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[PATCH v8 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:10 +0200
  [PATCH v8 31/41] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 15/41] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 03/41] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 12/41] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 14/41] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 33/41] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 06/41] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 09/41] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
    Re: [PATCH v8 09/41] richacl: Update the file masks in chmod() "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 17:30 +0200
      Re: [PATCH v8 09/41] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-29 01:50 +0200
  [PATCH v8 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 27/41] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 19/41] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 21/41] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 20/41] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 32/41] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 26/41] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 01/41] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 41/41] richacl: uapi header split Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 18/41] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 17/41] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 35/41] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 38/41] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 36/41] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 16/41] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 25/41] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 40/41] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 11/41] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 08/41] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 34/41] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 05/41] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 28/41] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 04/41] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 22/41] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 37/41] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 29/41] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 39/41] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
  [PATCH v8 24/41] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:30 +0200
  [PATCH v8 23/41] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:30 +0200
  [PATCH v8 30/41] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:30 +0200
  [PATCH v8 07/41] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:40 +0200
  [PATCH v8 10/41] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:40 +0200
    Re: [PATCH v8 10/41] richacl: Permission check algorithm "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 18:10 +0200
      Re: [PATCH v8 10/41] richacl: Permission check algorithm Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-28 18:30 +0200
        Re: [PATCH v8 10/41] richacl: Permission check algorithm "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 18:30 +0200
          Re: [PATCH v8 10/41] richacl: Permission check algorithm Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-28 19:00 +0200
  [PATCH v8 02/41] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:50 +0200
  Re: [PATCH v8 00/41] Richacls "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 18:40 +0200
    Re: [PATCH v8 00/41] Richacls Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-28 19:20 +0200
      Re: [PATCH v8 00/41] Richacls "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 19:50 +0200
        Re: [PATCH v8 00/41] Richacls Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-29 17:00 +0200
  Re: [PATCH v8 00/41] Richacls Christoph Hellwig <hch@infradead.org> - 2015-10-04 08:30 +0200
    Re: [PATCH v8 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-05 20:50 +0200
      Re: [PATCH v8 00/41] Richacls Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-10-05 21:00 +0200
      Re: [PATCH v8 00/41] Richacls Dave Chinner <david@fromorbit.com> - 2015-10-05 23:20 +0200
        Re: [PATCH v8 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-06 00:10 +0200

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