3 files changed, 38 insertions, 10 deletions

diff --git a/console.h b/console.h
index 3157330eb2..f4e4741091 100644
--- a/console.h
+++ b/console.h
@@ -369,6 +369,7 @@ void vnc_display_init(DisplayState *ds);
 void vnc_display_close(DisplayState *ds);
 int vnc_display_open(DisplayState *ds, const char *display);
 int vnc_display_password(DisplayState *ds, const char *password);
+int vnc_display_disable_login(DisplayState *ds);
 int vnc_display_pw_expire(DisplayState *ds, time_t expires);
 void do_info_vnc_print(Monitor *mon, const QObject *data);
 void do_info_vnc(Monitor *mon, QObject **ret_data);
diff --git a/monitor.c b/monitor.c
index c5f54f46c7..64e41e3e7d 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1018,6 +1018,14 @@ static int do_quit(Monitor *mon, const QDict *qdict, QObject **ret_data)
 
 static int change_vnc_password(const char *password)
 {
+    if (!password || !password[0]) {
+        if (vnc_display_disable_login(NULL)) {
+            qerror_report(QERR_SET_PASSWD_FAILED);
+            return -1;
+        }
+        return 0;
+    }
+
     if (vnc_display_password(NULL, password) < 0) {
         qerror_report(QERR_SET_PASSWD_FAILED);
         return -1;
@@ -1117,6 +1125,8 @@ static int set_password(Monitor *mon, const QDict *qdict, QObject **ret_data)
             qerror_report(QERR_INVALID_PARAMETER, "connected");
             return -1;
         }
+        /* Note that setting an empty password will not disable login through
+         * this interface. */
         rc = vnc_display_password(NULL, password);
         if (rc != 0) {
             qerror_report(QERR_SET_PASSWD_FAILED);
diff --git a/ui/vnc.c b/ui/vnc.c
index 495d6d6ef1..8067b313f7 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -2084,7 +2084,7 @@ static int protocol_client_auth_vnc(VncState *vs, uint8_t *data, size_t len)
     unsigned char key[8];
     time_t now = time(NULL);
 
-    if (!vs->vd->password || !vs->vd->password[0]) {
+    if (!vs->vd->password) {
         VNC_DEBUG("No password configured on server");
         goto reject;
     }
@@ -2484,6 +2484,24 @@ void vnc_display_close(DisplayState *ds)
 #endif
 }
 
+int vnc_display_disable_login(DisplayState *ds)
+{
+    VncDisplay *vs = ds ? (VncDisplay *)ds->opaque : vnc_display;
+
+    if (!vs) {
+        return -1;
+    }
+
+    if (vs->password) {
+        qemu_free(vs->password);
+    }
+
+    vs->password = NULL;
+    vs->auth = VNC_AUTH_VNC;
+
+    return 0;
+}
+
 int vnc_display_password(DisplayState *ds, const char *password)
 {
     VncDisplay *vs = ds ? (VncDisplay *)ds->opaque : vnc_display;
@@ -2492,19 +2510,18 @@ int vnc_display_password(DisplayState *ds, const char *password)
         return -1;
     }
 
+    if (!password) {
+        /* This is not the intention of this interface but err on the side
+           of being safe */
+        return vnc_display_disable_login(ds);
+    }
+
     if (vs->password) {
         qemu_free(vs->password);
         vs->password = NULL;
     }
-    if (password && password[0]) {
-        if (!(vs->password = qemu_strdup(password)))
-            return -1;
-        if (vs->auth == VNC_AUTH_NONE) {
-            vs->auth = VNC_AUTH_VNC;
-        }
-    } else {
-        vs->auth = VNC_AUTH_NONE;
-    }
+    vs->password = qemu_strdup(password);
+    vs->auth = VNC_AUTH_VNC;
 
     return 0;
 }