[evolution-kolab] CamelKolabSession: let CamelTCPStreamSSL temporarily accept new server certs

[Christian Hilberg <chilberg src gnome org>]

commit 9b4cf47810ae74c24277b109dade63b8f8bc83bc
Author: Christian Hilberg <hilberg kernelconcepts de>
Date:   Tue Oct 30 20:59:36 2012 +0100

    CamelKolabSession: let CamelTCPStreamSSL temporarily accept new server certs
    
    * When seeing a new server certificate for the first time,
      which it cannot automatically validate by chaining-up the CA,
      CamelTCPStreamSSL::ssl_bad_cert() will invoke the
      CamelSession::alert_user() function to query the user whether
      the certificate should or should not be accepted. In the
      evolution-kolab plugin, the collection backend will be the first
      one to arrive there, then the cal/book backends, each in separate
      processes. Last, Evo itself will arrive in its own CamelSession
      implementation's alert_user(), which displays the accept/decline dialog.
      The best we can do at the moment is to temporarily accept
      the server cert in backend (collection/calendar/contacts)
      context, since the certificate is *always* written into the
      Camel cert_db by CamelTCPStreamSSL::ssl_bad_cert(), only the
      trust level is set according to the user selection in alert_user().
      That means we need to act here and cannot just fail to let Evo
      handle everything. If we temporarily accept, Evolution will still
      ask for certificate accept/decline, and the result will be written
      to the cert_db, from where the trust level selection is picked
      up on next E-D-S restart

 src/libekolab/camel-kolab-session.c |   47 +++++++++++++++++++++++++++++++++-
 1 files changed, 45 insertions(+), 2 deletions(-)
---
diff --git a/src/libekolab/camel-kolab-session.c b/src/libekolab/camel-kolab-session.c
index 82db489..0e501dd 100644
--- a/src/libekolab/camel-kolab-session.c
+++ b/src/libekolab/camel-kolab-session.c
@@ -318,17 +318,60 @@ kolab_session_alert_user (CamelSession *session,
                           const gchar *prompt,
                           GSList *button_captions)
 {
+	gint rval = -1;
+
 	g_return_val_if_fail (CAMEL_IS_SESSION (session), -1);
 	/* prompt may be NULL */
 	(void) button_captions;
 
 	/* should we even pop up a dialog from within E-D-S? */
 	if (prompt != NULL) {
-		g_warning ("%s()[%u] (%u) Error: %s",
+		g_warning ("%s()[%u] (%u) \n%s",
 		           __func__, __LINE__, type, prompt);
 	}
 
-	return -1;
+	/* XXX SSL certificate workaround
+	 *
+	 * When seeing a new server certificate for the first time,
+	 * which it cannot automatically validate by chaining-up the CA,
+	 * CamelTCPStreamSSL::ssl_bad_cert() will invoke this function
+	 * to query the user whether the certificate should or should not
+	 * be accepted. In the evolution-kolab plugin, the collection
+	 * backend will be the first one to arrive here, then the cal/book
+	 * backends, each in separate processes. Last, Evo itself will
+	 * arrive in its own CamelSession implementation's alert_user(),
+	 * which displays the accept/decline dialog. Current implementation
+	 * of CamelTCPStreamSSL::ssl_bad_cert() does the following, based
+	 * on the return value of this function:
+	 *
+	 * 0: reject the cert in question
+	 * 1: temporarily accept the cert in question
+	 * 2: permanently accept the cert in question
+	 *
+	 * all else is regarded "fail and ask again"
+	 *
+	 * The best we can do here at the moment is to temporarily accept
+	 * the server cert in backend (collection/calendar/contacts)
+	 * context, since the certificate is *always* written into the
+	 * Camel cert_db by CamelTCPStreamSSL::ssl_bad_cert(), only the
+	 * trust level is set according to the user selection in alert_user().
+	 * That means we need to act here and cannot just fail to let Evo
+	 * handle everything. If we temporarily accept, Evolution will still
+	 * ask for certificate accept/decline, and the result will be written
+	 * to the cert_db, from where the trust level selection is picked
+	 * up on next E-D-S restart
+	 */
+
+	if (g_slist_length (button_captions) == 3)
+		/* this is some guessing about whether
+		 * we're asked for server cert accept/decline
+		 * (cannot parse button captions or prompt,
+		 * since these will be translated, but bad_cert()
+		 * is the only instance calling us - good luck!)
+		 */
+		rval = 1; /* temporarily accept, Evo will ask for confirmation */
+
+	return rval;
 }
 
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