Unix file protection ACLs

Fixed-structure, discretionary ACL

Each file system object has an ACL

• Binding 3 rights to 3 subjects.

• Only the owner can update the ACL.

Rights: R W X

• Read (file data)/List directory.

• Write (file data)/create or remove files or subdirectories.

• Execute/use as process’ current working directory.

Subjects

• An UID (owner).

• A GID.

• Others.