vnc: call sasl_server_init() only when required

VNC server is calling sasl_server_init() during startup of QEMU, even
if SASL auth has not been enabled.

This may create undesirable warnings like "Could not find keytab file:
/etc/qemu/krb5.tab" when the user didn't configure SASL on host and
started VNC server.

Instead, only initialize SASL when needed. Note that HMP/QMP "change
vnc" calls vnc_display_open() again, which will initialize SASL if
needed.

Fix assignment in if condition, while touching this code.

Related to:
https://bugzilla.redhat.com/show_bug.cgi?id=1609327

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20180907063634.359-1-marcandre.lureau@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/ui/vnc.c b/ui/vnc.c
index 916a16d312..cf221c83cc 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -3821,9 +3821,6 @@ void vnc_display_open(const char *id, Error **errp)
     bool reverse = false;
     const char *credid;
     bool sasl = false;
-#ifdef CONFIG_VNC_SASL
-    int saslErr;
-#endif
     int acl = 0;
     int lock_key_sync = 1;
     int key_delay_ms;
@@ -3963,10 +3960,14 @@ void vnc_display_open(const char *id, Error **errp)
     trace_vnc_auth_init(vd, 1, vd->ws_auth, vd->ws_subauth);
 
 #ifdef CONFIG_VNC_SASL
-    if ((saslErr = sasl_server_init(NULL, "qemu")) != SASL_OK) {
-        error_setg(errp, "Failed to initialize SASL auth: %s",
-                   sasl_errstring(saslErr, NULL, NULL));
-        goto fail;
+    if (sasl) {
+        int saslErr = sasl_server_init(NULL, "qemu");
+
+        if (saslErr != SASL_OK) {
+            error_setg(errp, "Failed to initialize SASL auth: %s",
+                       sasl_errstring(saslErr, NULL, NULL));
+            goto fail;
+        }
     }
 #endif
     vd->lock_key_sync = lock_key_sync;