topic Re: How to force a password change? in Operating System - Linux

How to force a password change?

Bolek Mynarski — Tue, 20 Jun 2000 18:13:51 GMT

O.K. I posted this message in the RedHat newsgroup but no go.

On HP-UX, setting someone's password with an -f parameter, will force that user to change his/her password next time the log on, like so:

passwd -f user

In Linux, it has a completely different meaning. I was browsing through man pages on passwd but could not find anything that would remotely resemble my "passwd -f" from HP-UX.

Any ideas?

Thanks.

Re: How to force a password change?

Albert E. Whale, CISSP — Tue, 20 Jun 2000 19:54:42 GMT

Boleslaw,

The command you are looking for is called chage. I believe that you need the shadow password package inorder to manipulate the password age and expiration dates.

I have attached the man Page for you.

Chage is part of the Shadow Utils Package.

I am running Linux Mandrake 7.0, but I'm sure there are similar tools available at your local RedHat RPM Mirror.

[root@offsite1 /root]# which chage
/usr/bin/chage
[root@offsite1 /root]# rpm -qf /usr/bin/chage
shadow-utils-19990827-3mdk
[root@offsite1 /root]#

Hope that helps!

Re: How to force a password change?

Bolek Mynarski — Tue, 20 Jun 2000 23:57:26 GMT

Hi Albert,

That's not what I'm looking for. "chage" would be an equivalent of secure accounts on HP-UX. What I am looking for is something as simple as (taken from HP-UX):

passwd -f user

which will force that user to change his/her password at the next logon. No fooling around with password age, minimum and maximum number of days and so on. :-(

So far, this is the only shortcoming I've seen on part of Linux in comparison to HP-UX (except for LVM which would be a killer app if Linux had it).

Re: How to force a password change?

Dan Am — Wed, 21 Jun 2000 08:39:55 GMT

to my surprise: you seem to be right.
but you can handle it, by adding :
-----
if [ -e .pw_lock ]
then
passwd
rm .pw_lock
fi
-----
to users .profile.

then write a script "pwforce" or s'thing
containing:
-----
touch /home/$1/.pw_lock
chown $1 /home/$1/.pw_lock
-----
$1 being your user and assuming your HOME-dirs have the naming-convention
/home/

Re: How to force a password change?

Dan Am — Wed, 21 Jun 2000 08:43:29 GMT

BTW:

Suse-Distro has LVM. Bit shaky still, esp.
when you set it up, but works on this very machine, striping and all.

Re: How to force a password change?

Albert E. Whale, CISSP — Wed, 21 Jun 2000 12:39:54 GMT

Boleslaw,

I believe that if you use:
chage -M 0

you will acheive the same functionality.

Here's the excerpt I am reading from the man pages.

With the -M option, the value of maxdays is the maximum number of days during which a password is valid. When maxdays plus lastday is less than the current day, the user will be required to change her password before being able to use her account. This occurance can be planned for in advance by use of the -W option, which provides the user with advance warning.

Hope this helps.

Re: How to force a password change?

Bolek Mynarski — Wed, 21 Jun 2000 18:38:44 GMT

Hi Albert,

I read man pages too. After trying it (last night) and today (one more time with chage -M 0 user), I'm getting this:

Warning: your password will expire in -2 days

and you can happily login with the same password over and over again.

I'll take a look at the script way later on but it already seems like it's going to be a lot of hassle. I miss my passwd -f user from HP-UX :-(

Re: How to force a password change?

Albert E. Whale, CISSP — Wed, 21 Jun 2000 19:00:17 GMT

Boleslaw,

We're going to solve this yet, but I need a few points to conitnue this train ....

Then send us the following

chage -l

I want to see what the 2 days is, Probably a warnign field which needs to be reset in order to take effect immediately.

Don't give up on chage yet.

Re: How to force a password change?

Michael Worsham — Tue, 02 Oct 2001 17:24:42 GMT

Take a look at www.google.com and search for 'password aging'. Note that this can only be done on Linux systems that are using shadowed passwords.

For addition reference, check:
http://www.cis.ohio-state.edu/~mamrak/CIS762/unix_encryption_tut.html
http://www.linux.com/howto/Shadow-Password-HOWTO-7.html

Re: How to force a password change?

Brian Roberson — Tue, 18 Dec 2001 22:06:38 GMT

CHANGELOG FROM shadow-utils:
shadow-960129 => shadow-960810
- SunOS4-like passwd -e (force change on next login) (isexpired.c, passwd.c)

Re: How to force a password change?

Jonathan Pulfer — Thu, 17 Jan 2002 18:27:21 GMT

try

passwd -x user

Cheers
John

Re: How to force a password change?

Christoph Rothe_3 — Tue, 12 Mar 2002 10:44:50 GMT

Hi,

I think I got a solution:

chage supports an option -d which sets the date of last password change.

So if you want to force your user to change his/her passwort after 90 days, you would enter the following command:

chage -M 90 username

Now you want him to change his passwort immediately, so today (12.03.2002) you would do the following

chage -M 90 -d 12.12.2001 username

I think it would be much easier to let the computer do the work...

I did not test this but possibly this could work to calculated the date in UNIX time format.

bc `date +%s` - (24*60*60*90)

Unfortunately I do not know how to convert this back to a normal date format.

Christoph

Re: How to force a password change?

Christopher C. Weis — Thu, 14 Mar 2002 05:20:34 GMT

The man page is not written particularly well, but the following has been tested and works...

prompt> chage -d 0 username

or...

chage the third field in /etc/shadow entry to a 0 (zero, not capital "o").

I hope this helps.

Re: How to force a password change?

Bjoern Myrland — Thu, 14 Mar 2002 15:22:23 GMT

This should work:
# chage -m0 -M99999 -d0 login_name

Re: How to force a password change?

solution42 — Fri, 09 Aug 2002 10:11:28 GMT

Hello

On my linux work:

passwd -e username