Read Access Control Lists

• ACLs are layered on top of Linux permissions.
  • Can’t use standard tools such as ls to list those.
• An example:
  • mkdir aclexercise
  • touch aclfile
  • To read the ACLs on the file, we would use the getfacl command.
    • Installed by default on CentOS.
      • getfacl aclfile
    • For example, you would see a similar output to this: `getfacl temp

      file: temp

      owner: howard

      group: howard

      user::rw- group::r– other::r–

• Lists the standard Linux permissons.
• Can list the same permissions in tabular format.
  • Easier to see which permissions belong to each user.
  • getfacl -t aclfile `getfacl -t temp

    file: temp

    USER howard rw- GROUP howard r– other r–`

• Can set ACLs using setfacl.
  • setfacl -m user:root:rwx aclfile
    • The -m is for modify.
    • The username here would be root.
    • Then the permissions come after that, which in this case is rwx.
      • Sets an ACL for a root user.
• Then the file would look something like this: `getfacl -t temp

  file: temp

  USER howard rw- user root rwx GROUP howard r– mask rwx other r–`

• Will see on CentOs that the permissions of the file will now look like -rw-rwxr--+, notice the + at the end.
  • On Garuda Linux anyway, it looks like an @ –> .rw-rwxr--@
    • Shows we have an ACL on the file.
    • Also notice from the previous example, there is a mask line:
    • mask rwx
      • Shows the maximum allowed permissions.
• Can also list permissions recursively.
  • getfacl -R /home > home-perms.txt
• Can see more information by using man getfacl