who knows

[Computerabc]

I am Linux user I installed one Linux Server and created users.
you all know the password entries are in \etc\passwd file and \etc\shadow file which is only accessible by root means root has rights to read,write or modified but nobody else, so pls tell me how the user himself change his password and write a entery in etc\shadow file pls tell.

 

[pansophic]

In Linux, the Pluggable Authentication Modules (pam) perform both the authentication and the updating of user tokens. The user runs the passwd application, which calls the pam libraries, first to authenticate the user, then to update that user's security tokens. The user is never directly interacting with the /etc/shadow file.
pansophic