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Date:      Sat, 19 Jan 2002 20:03:16 +0300
From:      "Andrey A. Chernov" <ache@nagual.pp.ru>
To:        Dag-Erling Smorgrav <des@ofug.org>, mark@grondar.za
Cc:        cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject:   For all who miss it, PAM changes explanation reposted
Message-ID:  <20020119170316.GA11315@nagual.pp.ru>
In-Reply-To: <xzp1ygm9vc8.fsf@flood.ping.uio.no>
References:  <200201190901.g0J91H641020@freefall.freebsd.org> <xzp1ygm9vc8.fsf@flood.ping.uio.no>

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On Sat, Jan 19, 2002 at 17:08:55 +0100, Dag-Erling Smorgrav wrote:

> *detailed* explanation of what you think is wrong and why you think
> your patch is correct.

Here it is again modulo exact PAM_CRED_ERR code choosing I not insist on:
--------------------------------------------------------------------

More about pam_opie+pam_unix chain, i.e. how it was broken and is fixed:

In old variant pam_opie return two states, PAM_SUCCESS and PAM_AUTH_ERR.

1) If we chain it as "sufficient" and get failure, it falls to pam_unix
unconditionally, but must do that only when opiefileaccess()+opiealways() 
permits. This is dangerous from security sense.

2) If we chain it as "required" and get success, we'll get failure in the 
next pam_unix in the chain due to wrong password.

3) If we chain it as "requsite" and get failure, it stop whole chain 
unconditionally, but must fallback to pam_unix when 
opiefileaccess()+opiealways() permits.

4) If we chain it as "optional", ther is no sense to keep it since 
non-optional pam_unix is already in the chain.

All it means that there must be 3-state machine for pam_opie: PAM_SUCCESS, 
PAM_AUTH_ERR and some 3rd, PAM_CRED_ERR.
In that case we can do 1) for PAM_SUCCESS and PAM_AUTH_ERR and disable 
fallback to pam_unix for PAM_CRED_ERR case.


-- 
Andrey A. Chernov
http://ache.pp.ru/

-- 
Andrey A. Chernov
http://ache.pp.ru/

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