[OpenAFS] Question about append-only directories and ownership of files
Dexter 'Kim' Kimball
dhk@ccre.com
Mon, 21 Mar 2005 10:46:12 -0700
You don't mention the other half of the ACL. Who has "wilk" permissions?
In general AFS doesn't care about ownership/mode bits -- ignores them
entirely on directories, but does apply the owner mode bits to all users,
including the owner. (Doesn't seem relevant here but sometimes good to
know.)
Kim
=================================
Kim (Dexter) Kimball
CCRE, Inc.
kim<dot>kimball<at>jpl.nasa.gov
dhk<at>ccre.com
> -----Original Message-----
> From: openafs-info-admin@openafs.org
> [mailto:openafs-info-admin@openafs.org] On Behalf Of Thomas M. Payerle
> Sent: Friday, March 18, 2005 6:58 PM
> To: openafs-info@openafs.org
> Subject: [OpenAFS] Question about append-only directories and
> ownership of files
>
>
> I have a cgi script on a web server writing into an AFS
> directory with
> ACL rights wilk; i.e. "write" permission set minus the "r".
> The desired
> intent was to create a directory containing a file which the
> cgi script can
> append to, but would be unable to read from.
>
> The above appeared to be working as I expected, until I
> started testing out
> a replacement web server machine (having a different
> hostname, thus the
> httpd.hostname principal is different). Even when the ACL list in the
> parent (and all ancestral) directories are the same for both
> instances,
> the "wilk" permission set does not appear to be sufficient
> for appending
> _UNLESS_ the principal also is the owner of the file (the old
> server owned
> the files, and so worked without problem).
>
> It is happy if it has the "r" permission added to the set,
> and does not
> even change the owner after appending. It also is happy if
> the owner of the
> file is changed and the "r" permission not added.
>
> I have tested this out even with simple "echo 'AAA' >> file"
> type commands,
> so it does not appear to be an artifact of perl.
>
> As AFS generally tends to be somewhat unconcerned about file
> ownership in
> most cases, this ownership dependency was unexpected. I
> searched some texts
> and the web on AFS ACL rights, and although only one
> explicitly mentioned
> "append" rights
> (http://www.engin.umich.edu/caen/technotes/afs.pdf) (stating
> that "w" permission sufficient for that), the more common
> definition of
> "w" as allowing modification of files content seems
> consistent with that.
>
> Is this behavior "expected"? Am I missing something? Is
> there a way in
> AFS to have a file be append-only (possibly with creation if
> missing, but
> without being "readable") that does not depend on the
> principal appending
> to the file owning the file?
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