Re: [nfsv4] Fwd: New Version Notification for draft-dnoveck-nfsv4-security-04.txt

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On Sun, Jan 09, 2022 at 11:15:34PM +0000, Rick Macklem wrote:
> From: David Noveck wrote:
> > If I understand correctly, you are intending to accept an acl that APPEND_DATA and not
> > WRITE_DATA  and then not let the user open the file for write.   I don't know about your
> > users but I would certainly feel that was a "weird, irritating inconsistency".
> Yes, but it is consistent with local behaviour on FreeBSD.
> A file with APPEND_DATA, but not WRITE_DATA cannot be open'd with a POSIX
>   open("foo", O_APPEND | O_WRONLY, 0)
> either locally nor over NFS.
> (O_APPEND is a modifier and cannot be specified by itself.)

How would an NFS client write to it, anyway?  Do you just tell people
they need to use O_SYNC for such files?

Otherwise writes are likely to get reordered, and then the writer gets
random EACCES (and random unfillable holes, if you allow writes at
offsets past EOF).  Seems like a bit of a foot-gun.

Oh well, out of scope here, I suppose.

--b.