cvs commit: src/lib/libpam/modules/pam_unix pam_unix.8 pam_unix.c

[Ceri Davies]

On Fri, Apr 27, 2007 at 08:07:40PM +0400, Yar Tikhiy wrote:
> On Thu, Apr 26, 2007 at 12:46:38PM +0100, Ceri Davies wrote:
> > On Thu, Apr 26, 2007 at 01:54:59PM +0300, Alexandr Kovalenko wrote:
> > > Hello, Yar Tikhiy!
> > > 
> > > On Thu, Apr 26, 2007 at 06:39:01AM +0000, you wrote:
> > > 
> > > > yar         2007-04-26 06:39:01 UTC
> > > > 
> > > >   FreeBSD src repository
> > > > 
> > > >   Modified files:        (Branch: RELENG_6)
> > > >     lib/libpam/modules/pam_unix pam_unix.8 pam_unix.c 
> > > >   Log:
> > > >   MFC:
> > > >           pam_unix.c      1.52
> > > >           pam_unix.8      1.13
> > > >   
> > > >     In account management, verify whether the account has been locked
> > > >     with `pw lock', so that it's impossible to log into a locked account
> > > >     using an alternative authentication mechanism, such as an ssh key.
> > > >     This change affects only accounts locked with pw(8), i.e., having a
> > > >     `*LOCKED*' prefix in their password hash field, so people still can
> > > >     use a different pattern to disable password authentication only.
> > > 
> > > Using the very same logic you should also add checking for '*', and for
> > > any other string, which cannot be in password hash of different
> > > algorithms. By the way, what if some crypto algorithm, which will be
> > > used for password hashing can produce hash, which contains substring
> > > '*LOCKED*' ?
> > 
> > We really need to grow the same mechanism for this as Solaris has.
> > The way that this works is:
> > 
> >   o If the password hash begins *NP* then the user has no password
> >      and password authentication will always fail.
> > 
> >   o If the password hash begins *LK* then the account is considered
> >      locked and all authentication fails.  Also, cron and at will
> >      not run jobs for that user.
> > 
> >   o Anything else, the account is considered enabled (although of
> >      course, password checking can still fail if the hash is not
> >      valid).
> > 
> > I couldn't care less what the strings actually are, but we should
> > probably use *LOCKED* for the locked case, although I can see that we
> > may wish to use something else to provide a somewhat backward compatible
> > route - those who have been using the string *LOCKED* as stated in the
> > pw manual would get the same behaviour that they do now.
> > 
> > I am willing to work on this, but not without general agreement on the
> > above.
> 
> I believe that general consensus in PR bin/71147 was that in FreeBSD
> a *LOCKED* prefix means the account is totally locked out while a
> single asterisk in the password field means password authentication
> is disabled.  And, it isn't unfounded.  That practice has already
> been supported by adduser(8) for quite a while.  Now OpenSSH, too,
> looks for *LOCKED* as the FreeBSD-specific indication of an account
> being locked out if PAM isn't used.  So I see my change to pam_unix(8)
> just as a step in the direction we've already been moving in.  To
> match Solaris, we just need to document our practice well.

Well, we currently have an *NP* case as per above, but not a *LK* case,
so I disagree somewhat.

Ceri
-- 
That must be wonderful!  I don't understand it at all.
                                                  -- Moliere
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