[libvirt] [PATCH] sasl: Fix authentication when using PLAIN mechanism

[Christophe Fergeau]

On Thu, Nov 21, 2013 at 04:45:32PM -0700, Eric Blake wrote:
> On 11/21/2013 10:56 AM, Christophe Fergeau wrote:
> > With some authentication mechanism (PLAIN for example), sasl_client_start()
> > can return SASL_OK, which translates to virNetSASLSessionClientStart()
> > returning VIR_NET_SASL_COMPLETE.
> > cyrus-sasl documentation is a bit vague as to what to do in such situation,
> > but upstream clarified this a bit in
> > http://asg.andrew.cmu.edu/archive/message.php?mailbox=archive.cyrus-sasl&msg=10104
> > 
> > When we got VIR_NET_SASL_COMPLETE after virNetSASLSessionClientStart() and
> > if the remote also tells us that authentication is complete, then we should
> > end the authentication procedure rather than forcing a call to
> > virNetSASLSessionClientStep(). Without this patch, when trying to use SASL
> > PLAIN, I get:
> > error :authentication failed : Failed to step SASL negotiation: -1
> > (SASL(-1): generic failure: Unable to find a callback: 32775)
> > 
> > This patch is based on a spice-gtk patch by Dietmar Maurer.
> > ---
> >  src/remote/remote_driver.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c
> > index 7181949..e15eeaf 100644
> > --- a/src/remote/remote_driver.c
> > +++ b/src/remote/remote_driver.c
> > @@ -4125,6 +4125,9 @@ remoteAuthSASL(virConnectPtr conn, struct private_data *priv,
> >       * Even if the server has completed, the client must *always* do at least one step
> >       * in this loop to verify the server isn't lying about something. Mutual auth */
> 
> This code comment is now stale.  Can you touch it up?


I've changed it to:
    /* Loop-the-loop...
     * Even if the server has completed, the client must loop until sasl_client_start() or
     * sasl_client_step() return SASL_OK to verify the server isn't lying
     * about something. Mutual auth
     * */

Christophe
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