Directory with read and write for a user is permission denied, but fine with execute permissions

Question

I have some weirdness with my users/permissions. I currently have a user named world that has the groups world www-data admin. I have a directory at /var/abc which has the permissions 0644 or rw-r--r--, the ownership of that directory is world:www-data.

For some reason, when I try to change into or list that /var/abc directory I get permission denied, however if I add the executable permission to the user, so it becomes 0744 or rwxr--r-- I am allowed to access everything.

I can't figure out what is going on, could anyone shed some light?

Answer 1

What you are seeing is normal and expected behaviour. The x bit is required on a directory to enter it, search through it, or execute a program in it. As you are trying to cd into the directory then without the x bit being set you can't. When you set the permissions to 744, your user world who is the owner of the directory then has full control and as you observed an do what they want.