[kwlug-disc] Access rights to file/folder

John Van Ostrand john at netdirect.ca
Thu Jul 29 10:14:39 EDT 2010

----- Original Message -----
> Ah, I'm sorry,, it's the Sgid that does the magic, not sticky.... my
> bad.

Yup, it's the setgid bit on a dir that forces new files and dirs to have the same group membership. Otherwise files will have the user's primary group and would be inaccessible by others sharing the directory.

I remember looking at ACLs years ago and deciding against them at the time. They must have not been widely supported at the time, or something else precluded their use.

I suspect dump will support ACLs but gnu tar doesn't. It seems the solution is to dump all the acls to a file (getfacl -R ...> acls.txt) and back that up with the files.

ACLs do solve a minor issue that we never fully resolved with standard posix perms. That was having two classes of users on a shared directory, e.g. one group with rw and another with read only. We could always do fine-grained access control using Samba, but we wanted perfection, meaning a user had the same permissions if they used FTP, or NFS, or AppleTalk or a shell.

John Van Ostrand 
CTO, co-CEO 
Net Direct Inc. 
564 Weber St. N. Unit 12, Waterloo, ON N2L 5C6 
Ph: 866-883-1172 x5102 
Fx: 519-883-8533 

Linux Solutions / IBM Hardware 

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