Samba – Copying files from OSX to samba, force create mode not working

This might help. I do something similar, but only one share is open to the group's users. Other shares are read-only except for a single maintainer user. The [global] section of my smb.conf is almost identical to yours, except I don't use the force create/directory mode directives (in my case, they'd interfere with the other shares).

Here's the share definition:

[shared stuff]
        comment = blah, blah, etc
        path = /path/to/share
        write list = @sambagroup
        force group = +sambagroup
        read only = yes
        directory mask = 0775
        create mask = 0664
        guest ok = yes
        invalid users = root
        case sensitive = True
        default case = lower
        preserve case = yes
        short preserve case = yes

The important stuff here are these:

• read only = yes -- by default, read only.
• guest ok = yes -- guests can browse.
• write list = @sambagroup -- Authenticated members of sambagroup can write.
• force group = +sambagroup -- The + means that the force only applies to existing members of sambagroup. They're already the only ones who can write. I think, without the +, guest is given sambagroup credentials, which is not wanted (particularly with the write list directive above).
• directory mask = 0775
• create mask = 0664

These do exactly what you want yours to do: "drwxrwxr-x" on directories, "rwxrwxr-x" on files, and newly created files are owned by the user and sambagroup. The maintainers of the other shares get the same permissions as everyone else when working in shared stuff, and permissions & groups are normal when they work in the other shares.

My smb.conf has been working with only minor tweaks through several different versions of Samba, and currently is used with Samba 3.2.5. I never had it running on Ubuntu 8.04, but it ran on Ubuntu 7.04 for a long time before getting migrated to a recent Debian Lenny install.

Is SELinux active? If it is, then you can make it accessible by setting the type to public_content_t. If samba should be able to write to it, then set the type to public_content_rw_t. Note that if you do the latter, you will also need to tell SELinux about this; my system-config-selinux has a boolean for this: Allow Samba to write files in directories labeled public_content_rw_t