On Tue, Aug 07, 2001 at 09:45:48PM -0400, Daniel J. Mastrian wrote:
> I've searched through the Linux-XFS mailing list archives, searched through
> google, and even skimmed the IEEE Posix 1003.1e draft standard, and perhaps
> I'm just dense, but I haven't found a sufficient answer to this question
> about ACLs (in general...although in this case I am using XFS on Linux)
> I want the user and group who owns /foo to have rw- for all files, and rwx
> for all directories. I want user apache to have r-- for all files, and r-x
> for all directories. Everyone else should have --- (although I want to
> leave the option open to give a specific user write access later on, for
> So say I set /foo to have this default ACL...
> Now, if I create a directory /foo/bar, bar has an access ACL and a default
> ACL identical to /foo's default ACL. Correct, intended behavior, yay.
> However, if I 'touch somefile', I get a file access ACL that is not what I
> I see two things wrong with this. (1) ACL_GROUP_OBJ has rwx perms. It
> should not be able to execute. I believe someone else on this list
> mentioned that this was part of the standard, although weird. If this is
> intended behavior, could someone please confirm it? (2) apache has r-x
> perms, and should also not have the execute bit set. Shouldn't the execute
> bit have been dropped by intersection with the rw-rw-rw- creation
The result you reported seems correct to me according to the standard.
* As you would probably know, the umask takes no effect
in this situation with a default ACL.
(just thought I'd mention it :)
* The mode bits of the creat/open called by touch (rw-rw-rw-)
are intersected with:
USER_OBJ ACE perms. - with the mode's user permissions
OTHER ACE perms. - with the mode's other permissions
GROUP_OBJ ACE perms. if there is no MASK ACE
- with the mode's group permissions
MASK ACE if there is one - with the mode's group permissions
Check out section 18.104.22.168 of standard - confusingly worded.
Note that if there is a MASK ACE, then the standard group permissions
(as seen with ls -l) will match the MASK ACE
(see section 23.1.2 of standard on File Permission bits).
* Thus, USER and GROUP ACEs are the same as the default ACLs';
they are not intersected with anything.
HOWEVER, the MASK ACE will be used with them in the ACL Access Check
algorithm (section 23.1.5 of standard).
* In your case, as we have a MASK ACE, the GROUP_OBJ permissions
are not intersected with the mode's group permissions,
the MASK ACE's permissions are set instead (as I said above)