passwd: authentication token manipulation error

If you are a Linux user, you may have encountered the error « passwd: authentication token error » when trying to change your password.

[root@Linux ~]# passwd user
Change password for user.
New password:
Retype the new password:
passwd: authentication token manipulation error

This error can be frustrating and confusing, especially if you are not familiar with the Linux command line. However, this error can be resolved and this article will guide you through the process of resolving this error.

Understanding the authentication token manipulation error

Before moving on to the steps for resolving this error, it is important to understand its.

The error occurs when the system fails to update the user’s authentication token.

An authentication token is a piece of information used to verify a user’s identity. When you log into your Linux system, your authentication token is generated and stored, and it is used to authenticate any action that requires administrative privileges, such as changing your password.

When the error « passwd: authentication token manipulation error » is displayed, it means that the system could not update your authentication.

Causes

There are several reasons why this error message may appear. Here are the ones I have encountered :

Read-only mounted file system

If the root file system is mounted as read-only, the password cannot be changed as both /etc/passwd and /etc/shadow cannot be changed.

To mount the root file system fas read-write, type the following mount command :

[root@Linux ~]# mount -rw -o remount /

[root@Linux ~]# mount | grep /dev/mapper/linux-root
/dev/mapper/rhel-root on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)

Root file system is full

If the root file system is full, the passwd program cannot modify both /etc/passwd and /etc/shadow. So check if the FS / is full with the df command :

[root@Linux ~]# df -h
Filesystem                           Size  Used Avail Use% Mounted on
devtmpfs                             3.9G     0  3.9G   0% /dev
tmpfs                                3.9G     0  3.9G   0% /dev/shm
tmpfs                                3.9G   25M  3.8G   1% /run
tmpfs                                3.9G     0  3.9G   0% /sys/fs/cgroup
/dev/mapper/Linux-root                25G   25G  1.2M   100% /
/dev/sda1                           1014M  225M  790M  23% /boot

If this is the root cause, free up the space in the root file system and the the problem will be solved.

To read this article in French click here.