Need solution to prevent deletion of files but allow editing and writing.

dsirrine · 12-08-2009, 10:42 AM

I am trying to figure out a solution to a problem I have been posed. I need to make it so that a file can be opened, edited, and saved, but not deleted. The chattr -u won't cut it because that still allows the delete. Also, chattr -i won't work either because that won't allow for opening, writing, and saving. Thank you in advance for your help.

bret381 · 12-08-2009, 10:47 AM

You can use the stickybit. chmod +t

I think it can only be used on directories..... someone correct me if I'm wrong

chrism01 · 12-08-2009, 05:11 PM

Yeah, -t is only for dirs and only stops non-owners from deleting. You can't stop the owner for obvious reasons.

Another way is this:

1. Create a new master user eg m1 and a grp grp1 (this will be m1's primary grp)
2. create a dir /home/gshare owned by m1:grp1
3. chgrp +s /home/gshare
4. add reqd users to grp grp1 as secondary group
5. have all files created by m1
6. set dir perms rwxr-x---
7. set file perms rwxrw----

estabroo · 12-08-2009, 05:18 PM

You could always make a directory that shadows the original one and has a hard link to each of the files, so even if they get removed out of the original the file still exists

Valery Reznic · 12-09-2009, 02:50 PM

Quote:

Originally Posted by dsirrine

I am trying to figure out a solution to a problem I have been posed. I need to make it so that a file can be opened, edited, and saved, but not deleted. The chattr -u won't cut it because that still allows the delete. Also, chattr -i won't work either because that won't allow for opening, writing, and saving. Thank you in advance for your help.

Just wondering - if one allowed to edit file (include remove all of it content) while one shouldn't be allowed to delete this file ?

jefro · 12-09-2009, 05:20 PM

You'd have to copy the file to a directory that the user can read and write to. Then on exit of app the script would do some compare to decide to edit original or leave. The original would have to be done with masked credentials. Might end up being hackable.

Wonder if NTFS formated partition would work?

lugoteehalt · 12-10-2009, 01:38 AM

Possibly not quite what you're after but might be part of a solution: the semi-legendary noclobber option. E.g.

SHELLOPTS=braceexpand:emacs:hashall:histexpand:interactive-comments:monitor:noclobber

catkin · 12-10-2009, 02:02 AM

Remove write permission on the directory the files are in. The files' content can be deleted (that counts as editing, right?) but the files cannot be removed.

Valery Reznic · 12-10-2009, 02:46 AM

Quote:

Originally Posted by catkin

Remove write permission on the directory the files are in. The files' content can be deleted (that counts as editing, right?) but the files cannot be removed.

Cool, I thought that removing write permission from directory will prevent file editing too, but I was wrong, it works.

Any idea WHY OP want such setup ?

lugoteehalt · 12-10-2009, 02:15 PM

Poisons rising from the gonads.

Valery Reznic · 12-10-2009, 02:46 PM

Quote:

Originally Posted by lugoteehalt

Poisons rising from the gonads.

Can you explain - I didn't catch it

lugoteehalt · 12-10-2009, 02:55 PM

Quote:

Originally Posted by Valery Reznic

Can you explain - I didn't catch it

I intended it as witty remark, calculated to spread happiness. Clearly I miscalculated.

Valery Reznic · 12-10-2009, 03:06 PM

Quote:

Originally Posted by lugoteehalt

I intended it as witty remark, calculated to spread happiness. Clearly I miscalculated.

May by you not miscalculated - just English is not my native language.