Re: Debian FEATURE: /home/loser is with permissions 755, default umask 0022

[Bob Friesenhahn <bfriesen () simple dallas tx us>]

On Thu, 8 Oct 2020, Seth Arnold wrote:

> On Wed, Oct 07, 2020 at 04:09:59PM -0500, Bob Friesenhahn wrote:
> > Ubuntu Linux (a Debian derivative) has changed the default.  However, we
> > found that the Ubuntu default caused problems for us while building our
> > software, and so we changed them back.
>
> Hello Bob, can you please share some details on this?
>
> I expect Ubuntu home directories to be 755 by default:
> https://wiki.ubuntu.com/SecurityTeam/Policies#Permissive_Home_Directory_Access
>
> And while it is very difficult to say "the umask", given that every
> process's umask setting depends upon the actions of not only itself but
> also its nearest parent to use the umask(2) syscall, but:
>
> $ grep ^UMASK /etc/login.defs
> UMASK           022

It seems that the issue we encountered is due to 'USERGROUPS_ENAB yes' 
in /etc/login.defs.  I am not sure if this is specific to Ubuntu. 
This setting changes the umask from the default:

# Enable setting of the umask group bits to be the same as owner bits
# (examples: 022 -> 002, 077 -> 007) for non-root users, if the uid is
# the same as gid, and username is the same as the primary group name.
#
# If set to yes, userdel will remove the user's group if it contains no
# more members, and useradd will create by default a group with the name
# of the user.
#
USERGROUPS_ENAB yes

Bob
--
Bob Friesenhahn
bfriesen () simple dallas tx us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
Public Key,     http://www.simplesystems.org/users/bfriesen/public-key.txt