RHEL 9 working with advance permissions Complete Access Control List tutorial Permissions PART-2
Advance Permission ACL (setfacl,getfacl) , chattr/lsattr-
ACLs allow us to apply a more specific set of permissions to a file or directory without (necessarily) changing the base ownership and permissions. They let us "tack on" access for other users or groups.
setfacl [option] [action/specification] file
getfacl file/directory_name
Types of ACL-
1.User Based ACL
2.Group Based ACL
Priority Rules for ACL processing-
Rule-1. User Based ACL has high priority over group based ACL.
Rule-2. If any same user is member of two or more groups then group having highest value permission for that file/dir get priority among all groups.
Rule-3. ACL is prioritize over Basic Chmod Permission.
On the basis of acessbility ACL can be also two types-
1.Access ACL- file or directory
2.Default ACL- Automatically apply on Directory after recuresively apllying Access ACL
chattr /lsattr- we can aply chattr command on any file/directory
After successfull application of CHATTR command root user is also not able to perform any operation on that file/dir .
It will save from acciendental modification/deletion of any file.
No one is able to create any user.