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Re: (ITS#6510) GSSAPI rebind proc will cause mutex deadlock
- To: openldap-its@OpenLDAP.org
- Subject: Re: (ITS#6510) GSSAPI rebind proc will cause mutex deadlock
- From: firstname.lastname@example.org
- Date: Fri, 9 Apr 2010 16:32:10 GMT
- Auto-submitted: auto-generated (OpenLDAP-ITS)
> On Apr 8, 2010, at 8:08 PM, Howard Chu wrote:
>> Kurt@OpenLDAP.org wrote:
>>> On Apr 8, 2010, at 3:58 PM, email@example.com wrote:
>>>> Sounds like your servers are mis-configured, it is not legal to send =
>>>> referral in response to a Bind request.
>>> I note that the technical specification doesn't actually preclude =
> return =3D
>>> of a referral in response to a Bind request. However, in practice, =
> such =3D
>>> return is quite problematic due to ambiguous semantics and security =3D=
>> Right. I can't find the discussion we had about this back in 2004, but =
> certainly we've already hashed this out in great detail before.
>> The fact is that acting on a referral simply means performing a Bind =
> against some other server.
>> It does nothing for the authentication state of the session on the =
> original server.
> Right, by returning a referral, regardless of how far the client got in =
> authentication process (including completion of all challenges), the =
> client is now anonymous at the original server.
> And there's a security concern, the referral information is not =
> protected by the underlying authentication mechanism. It is actually =
> quite possible that this be used by an attacker to cause the client to =
> try authentication multiple times, possibly with chosen plaintext.
> I recommend that the library never chase bind referrals.
Agreed. Patched in HEAD.
> (I tend to =
> think of rebind as a misfeature. Robust clients really should be using =
> the async API and carefully managing security contexts and chasing.)
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/