Passwd format?

[Pawel Wieleba]

On Sat, Nov 13, 2004 at 05:42:53PM +0100, Ivan Voras wrote:
> The Handbook and crypt(3) say passwords in master.passwd are MD5 hashes 
> if they start with $1$, for example:
> 
> $1$DP.s8oCc$VJo0/026/S5ng6HlD1Sz8/
> 
> the format is $1$salt$rest. I have several questions:
> 
> How are the values encoded? This looks something like base64.
> 
> Is it possible to actually verify the password against this format using 
> only a bare implementation of the md5 algorithm?

No.

> 
> Actually, the reason for these questions is that I'm considering using 
> LDAP authentication on a machine with lots of users and I'm wondering if 
> existing passwd information could be transported to LDAP. Any 
> experiences/docs on this?

Yes of course. I have migrated from /etc/master.passwd to LDAP.
I've used MigrationTools and changed them to support FreeBSD 
/etc/master.passwd file.
www.padl.com/download/MigrationTools.tgz
A patch to migrate_common.ph is available from my web:
www.iem.pw.edu.pl/~wielebap/ldap/migrationtools/migrate_common.ph.diff
A have created a new migrate_masterpasswd.pl (changed migrate_passwd.pl)
www.iem.pw.edu.pl/~wielebap/ldap/migrationtools/migrate_masterpasswd.pl

You can also use pam_ldap to migrate password hash from one to another 
hash format:
http://www.freebsd.org/cgi/query-pr.cgi?pr=71289
www.iem.pw.edu.pl/~wielebap/ldap/pam_ldap/pam_ldap_doc.pdf (section 1)

It may be helpful to see PRs:
http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/73448
http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/72867

Pawel Wieleba
P.Wieleba at iem.pw.edu.pl