converting password hashes

[John-Mark Gurney]

Wojciech Puchar wrote this message on Tue, Oct 29, 2019 at 13:13 +0100:
> i want to convert accouts from one system where there was mail-only 
> accounts using dovecot/postfix based system and SQL tables to my system, 
> where accounts are real unix accounts - that do mail and other things.
> 
> I don't know all people's plaintext passwords, and i don't need to and 
> want to, but i want new accounts to work with the same passwords
> 
> in SQL tables there are entries like this:
> 
> $1$aab7638c$Cn7BA/oU4mzr0QltXzV7Z0
> 
> and these works by simple cut and paste to /etc/master.passwd file
> 
> 
> but there are entries like:
> 
> {PLAIN-MD5}c575f55800a549930b9063b43af04f47
> 
> that doesn't
> 
> 
> is there a way to make it work without contacting over hundred people and 
> telling them what new password they have?

There's two ways, one is to write a PAM module or extend crypt(3) to
support the plain md5 format from postgresql.

The other option is to do what is called on-line conversion. Ask all
the affected users to login using their existing password, and as part
of the process, you now have their original password, so you jsut
re-crypt them w/ a compatible format, and then store and use the new
format.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."