[Samba] Behavior of acl_xattr:ignore system acls = yes on a share

[Bailey Allison]

Just wanted to say very interesting thread! I would like to share my experience as well if that's alright.

I have noticed when using the ignore system acls = yes value, when checking on the Windows side permissions it appears as the following (copying from Peter here):

-Permissions list-
root (Unix User\root)    Full Control    This folder only Domain Admins (Private\Domain Admins)    Read, write & Execute    This folder only SYSTEM    Full control    This folder only

Note that the group assigned on the Linux side gets read write execute, and the user gets Full Control. What does this mean? On Windows, read write execute is not enough to modify permissions on files or folders, so anyone in Domain Admins can access but not administer permissions for the share (i.e add users or groups, modify permissions). With the above permissions the only user who can actually edit the permissions on the Windows side is root, which is most likely not a good idea. Also where root isn't (shouldn't?) be a domain user, and is a linux user this also does not help.

Despite the underlying permissions being 0770 in this case, i.e user and group same on linux, they get interpreted differently on the Windows side. 

This could be an entirely Windows related thing, perhaps someone else can share their knowledge on this.

I am assuming by changing to 0777 the idea is that anyone can modify permissions? But where's there is no entry for everyone, and Domain Admins is still getting listed as read write execute, not sure if this would work. I will check in on this. Checking in on this as I write the email, 0777 adds an entry for Everyone also as read write execute, which is not enough to modify the permissions on the Windows side.

Peter, for your sake try assigning an admin account/your account as the owner user instead of root, and try modifying the permissions then to see if it works. You should see your account listed as Full Control, which should give you enough access to add and modify the permissions on Windows.

Happy to be corrected if there's something I'm completely missing/am incorrect about! 😊

Regards,

Bailey


> -----Original Message-----
> From: samba <samba-bounces at lists.samba.org> On Behalf Of Greg Sloop
> <gregs--- via samba
> Sent: January 30, 2024 6:33 PM
> To: samba at lists.samba.org
> Subject: Re: [Samba] Behavior of acl_xattr:ignore system acls = yes on a
> share
> 
> Perhaps everyone's clear on this - but I thought I should add this, just in case.
> (And perhaps the clarification should be added to the wiki.) When it says
> "Samba will ignore the standard Unix system ACL's (ugo)"
> This is technically true. HOWEVER!
> It only ignores the standard Unix system ACLS as it applies to SAMBA
> permissions.
> 
> This won't allow Samba to read files that the samba process can't read.
> Thus, set them to 0777 so there are no restrictions at the file system level,
> and then SAMBA will ignore the Unix ACL's for what permissions it gives to
> *SAMBA* users, and apply them purely based on the extended acls set in
> Windows, for example.
> 
> (Wording that properly is not exactly easy, but hopefully that's helpful.)
> 
> On Tue, Jan 30, 2024 at 12:24 PM Ralph Boehme via samba <
> samba at lists.samba.org> wrote:
> 
> > On 1/30/24 20:15, Peter Milesson via samba wrote:
> > > *Setup shared folder*
> > >
> > >   * Create the folder /data/migrtest
> > >   * Set ownership to root:"Domain Admins"
> > >   * chmod 0770 migrtest
> >
> > iirc this has to be 0777, otherwise the kernel gets in your way. You
> > only want Samba to enforce permissions so you have to get the kernel
> > filesystem permissions our of the way by goint with 0777.
> >
> > -slow
> >
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