cvs commit: src/lib/libpam/modules/pam_unix pam_unix.8
rea-fbsd at codelabs.ru
Thu Apr 26 13:58:58 UTC 2007
Alexander, good day.
Thu, Apr 26, 2007 at 01:54:59PM +0300, Alexandr Kovalenko wrote:
> > 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
No, Yar is talking about the _locked_ accounts only. '*' means
that user will not be able to authenticate with password.
> By the way, what if some crypto algorithm, which will be
> used for password hashing can produce hash, which contains substring
> '*LOCKED*' ?
We are not talking about the _substring_ -- we are talking about
_prefix_. Look into your /etc/master.passwd -- every password starts
with the '$<something>$' sequence that identifies the hashing algo.
So _no_ valid password field will have anything that starts with
'*' as the prefix.
> But anyway, I think that it is not expected behavour of sshd/pam_unix.
> >From the pw manual page:
> USER LOCKING
> The pw utility supports a simple _password_ locking mechanism for
> users; it works by prepending the string `*LOCKED*' to the
> beginning of the password field in master.passwd to prevent
> successful authentication.
> Please note word _password_. There is nothing about locking _account_
It is arguably as the 'ps' page talks about passwords only, but
can mean the accounts, because it was written with the password-auth
in mind. Moreover, the next paragraph is:
The lock and unlock commands take a user name or uid of the account to
lock or unlock, respectively. The -V, -C, and -q options as described
above are accepted by these commands.
Note the 'account' word in it.
> Please consider reviewing this PR and, hopefully, back out this commit.
> At least for a lot of people - it is POLA violation.
I think that it should be discuissed. Perhaps the Cerie's proposition
should be takes as the basis.
My two cents.
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