Postfix SMTP auth doesn't work with cyrus-sasl 2.1.25

[Quanah Gibson-Mount]

--On Tuesday, January 10, 2012 1:10 PM -0800 Quanah Gibson-Mount 
<quanah at zimbra.com> wrote:

> I would also note, that with cyrus-sasl 2.1.23, where things *work* just
> fine, I get the same result:
>
> root at zqa-061:/opt/zimbra/cyrus-sasl-2.1.23.3z/sbin# ./pluginviewer -a
> Installed auxprop mechanisms are:
> (null)
>
> It seems to me like the lack of auxprop mechanisms completely breaks
> Cyrus-SASL in 2.1.25, where as in 2.1.23, other plugins would continue to
> work.

Hi Dan,

In summary:

The reworking of _sasl_auxprop_lookup in 2.1.25 is completely broken.  By 
creating a return status that defaults to SASL_NOMECH, if someone builds 
cyrus-sasl with no auxprop mechanisms, all authentications fail because 
this one function cannot load the auxprop modules, since they don't exist.

This is even somewhat noted in one comment in the function itself:

        /* TODO: Ideally, each auxprop plugin should be marked if its 
failure
           should be ignored or treated as a fatal error of the whole 
lookup. */


I was able to get 2.1.25 to correctly work when there are no auxprop 
plugins with the following patch:

--- auxprop.c.orig      2012-01-11 12:34:03.948477379 -0800
+++ auxprop.c   2012-01-11 12:34:45.878474663 -0800
@@ -917,7 +917,10 @@
                         (sasl_callback_ft *)&getopt,
                         &context) == SASL_OK) {
        ret = getopt(context, NULL, "auxprop_plugin", &plist, NULL);
-       if(ret != SASL_OK) plist = NULL;
+       if(ret != SASL_OK) {
+               plist = NULL;
+               result = SASL_OK;
+       }
     }

     if(!plist) {


I.e., if we are not able to load the aux prop plugins when we call getopt, 
set plist to NULL and set the result to SASL_OK.

This is probably not the best solution in the world, as I imagine there may 
be other reasons why the getopt call here may fail, but it does return the 
behavior of the function to matching 2.1.23, and allows builds w/o auxprop 
to function correctly.

--Quanah

--

Quanah Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
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