setting default umask and user:group on directory

Question

I have a directory data and I need to set default umask and ownership for all directories/files (both existing and future files).

I want all files in data to have ownership root:martin ans permissions 750/640

I am aware that I can use setfacl to set default umask recursively using

setfacl -R -d -m o::--- data

and that I can use setgid bit on the directory, so that all created files have ownership root:martin

chmod -R +s data

What I am not sure about is whether I should combine setgid with acl. Can I perhaps achieve the same with acl only? How would I do it? Would that solution be superior?

Answer 1

Option 1: The permissions of the files inside the directory doesn't matter, blocking at the directory level is usually enough, so chmod 2750 /path-to-dir is enough.

Option 2: Use ACLs only (chmod 2750 /path-to-dir is not necessary, but make things nicer for people not used to ACLs).

setfacl -R -b -d -m o::--- -m u::rwX -m g::rX  .

note that you could set g::rwX to achieve 770/660