[GRASS-dev] mapset permissions: only owner should have write permissions

[Glynn Clements]

Markus Neteler wrote:

> The point here is (as experienced on our local shared network
> grassdata/ recently):
> - GRASS allows users to enter their own mapset(s)
> - GRASS allows users to read all mapsets and write into the current (own) one
> - GRASS does not allow to modify the mapset of a different user

In 7.0, the last one can be suppressed by setting the environment
variable GRASS_SKIP_MAPSET_OWNER_CHECK to any non-empty string.

Of course, you still need write permission on the underlying files and
directories.

> So far so nice.
> 
> Assume that several users belong to the same group. If now the group
> write flag is enabled for mapsets, users can delete them even if they
> are not their own. This is fine since someone (admin) must have
> allowed for this.
> 
> Now back to GRASS: A user runs a session in his/her mapset with
> group-write enabled. This is against the GRASS internal policy where
> others cannot write into your own mapsets with GRASS commands.
> 
> Wish for improvement:
> When starting a session in a mapset with group/other-write enabled,
> issue a warning to inform the user about this in the startup script.
> This would follow the "least-surprise" paradigm.
> Feasible?

Yes. Just don't do anything too invasive.

Bear in mind that paying too much attention to filesystem permissions
has a similar problem to the ownership check, namely that most Unix
systems are capable of accessing non-Unix filesystems (e.g. FAT, NTFS,
CIFS). This is one reason why I added the ability to suppress the
check.

-- 
Glynn Clements <glynn at gclements.plus.com>