Dear cp-Maintainer,
we ran into problems with cp -p on our Linux system when the file system
is configured to allow chown for normal users (eg
/proc/sys/fs/xfs/restrict_chown=0). As long as we used the IRIX cp was
used everything went fine, but with GNU cp we run into errors "cp:
preserving permissions for `testdir/f1': Operation not permitted"
because ownership is changed before changing permissions.
I do not understand the argument for this behaviour:
[cp.c]: /* Adjust the times (and if possible, ownership) for the copy.
chown turns off set[ug]id bits for non-root,
so do the chmod last. */
because for a non-root user the set[ug]id bits are either cleared by
chown or may not be set. To me the reason seems to be that there
shouldn't be an intermediate suid root binary if root copies a setuid
<other user> binary.
I do not believe that any special permissions should be preserved unless
the owner (and group) of the destination file is the same as the owner
of the source file.
I think the correct order of preserving mode and ownership is
1. change the standard permissions
2. change owner (if requested)
3. if (src_has_special_perms && owner_src == owner_dest && (user == root
|| user == owner_dest)) set special perms on dest file.
Mit freundlichen Gruessen / Best Regards
Axel PHILIPP Geb. 044/557
Dr. rer. nat., Dipl. Phys.
MTU Aero Engines GmbH
Informationswirtschaft/Entwicklungssysteme (FIE)
Information Management/Engineering Systems (FIE)
Dachauer Str. 665
80995 Muenchen
Germany
Tel +49 (0)89 1489-4715
Fax +49 (0)89 1489-97533
--
MTU Aero Engines GmbH
Geschaeftsfuehrung/Board of Management: Egon W. Behle, Vorsitzender/CEO; Dr.
Rainer Martens, Dr. Stefan Weingartner, Reiner Winkler
Vorsitzender des Aufsichtsrats/Chairman of the Supervisory Board: Klaus
Eberhardt
Sitz der Gesellschaft/Registered Office: Muenchen
Handelsregister/Commercial Register: Muenchen HRB 154230
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