vnc: fix resource leak when websocket channel error

When we connect to vnc by websocket channel, and disconnect
(maybe by some network exception) before handshake,
qemu will left CLOSE_WAIT socket and never close it

After 04d2529da2 ("ui: convert VNC server to use QIOChannelSocket")
and dd154c4d9f ("io: fix handling of EOF / error conditions in websock GSource"),
the vnc call qio_channel_add_watch only care about G_IO_IN,
but mising G_IO_HUP and G_IO_ERR.
When the websocket channel get EOF or error, it cannot callback,
because the caller ignore the event, that leads to resource leak

We need handle G_IO_HUP and G_IO_ERR event, then cleanup the channel

Fixes: 04d2529da2 ("ui: convert VNC server to use QIOChannelSocket")
Fixes: dd154c4d9f ("io: fix handling of EOF / error conditions in websock GSource")
Cc: qemu-stable@nongnu.org
Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Message-id: 20201029032241.11040-1-dinghui@sangfor.com.cn
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/vnc-auth-sasl.c

@@ -111,7 +111,8 @@ size_t vnc_client_write_sasl(VncState *vs)
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+            vnc_client_io, vs, NULL);
     }
 
     return ret;

ui/vnc-auth-vencrypt.c

@@ -79,7 +79,8 @@ static void vnc_tls_handshake_done(QIOTask *task,
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_OUT,
+            vnc_client_io, vs, NULL);
         start_auth_vencrypt_subauth(vs);
     }
 }

ui/vnc-jobs.c

@@ -151,7 +151,8 @@ void vnc_jobs_consume_buffer(VncState *vs)
             }
             if (vs->disconnecting == FALSE) {
                 vs->ioc_tag = qio_channel_add_watch(
-                    vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
+                    vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_OUT,
+                    vnc_client_io, vs, NULL);
             }
         }
         buffer_move(&vs->output, &vs->jobs_buffer);

ui/vnc-ws.c

@@ -41,13 +41,14 @@ static void vncws_tls_handshake_done(QIOTask *task,
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            QIO_CHANNEL(vs->ioc), G_IO_IN, vncws_handshake_io, vs, NULL);
+            QIO_CHANNEL(vs->ioc), G_IO_IN | G_IO_HUP | G_IO_ERR,
+            vncws_handshake_io, vs, NULL);
     }
 }
 
 
 gboolean vncws_tls_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
-                                GIOCondition condition G_GNUC_UNUSED,
+                                GIOCondition condition,
                                 void *opaque)
 {
     VncState *vs = opaque;
@@ -59,6 +60,11 @@ gboolean vncws_tls_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
         vs->ioc_tag = 0;
     }
 
+    if (condition & (G_IO_HUP | G_IO_ERR)) {
+        vnc_client_error(vs);
+        return TRUE;
+    }
+
     tls = qio_channel_tls_new_server(
         vs->ioc,
         vs->vd->tlscreds,
@@ -105,13 +111,14 @@ static void vncws_handshake_done(QIOTask *task,
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+            vnc_client_io, vs, NULL);
     }
 }
 
 
 gboolean vncws_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
-                            GIOCondition condition G_GNUC_UNUSED,
+                            GIOCondition condition,
                             void *opaque)
 {
     VncState *vs = opaque;
@@ -122,6 +129,11 @@ gboolean vncws_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
         vs->ioc_tag = 0;
     }
 
+    if (condition & (G_IO_HUP | G_IO_ERR)) {
+        vnc_client_error(vs);
+        return TRUE;
+    }
+
     wioc = qio_channel_websock_new_server(vs->ioc);
     qio_channel_set_name(QIO_CHANNEL(wioc), "vnc-ws-server-websock");
 

ui/vnc.c

@@ -1398,7 +1398,8 @@ static size_t vnc_client_write_plain(VncState *vs)
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+            vnc_client_io, vs, NULL);
     }
 
     return ret;
@@ -1435,7 +1436,8 @@ static void vnc_client_write(VncState *vs)
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+            vnc_client_io, vs, NULL);
     }
     vnc_unlock_output(vs);
 }
@@ -1551,6 +1553,12 @@ gboolean vnc_client_io(QIOChannel *ioc G_GNUC_UNUSED,
     VncState *vs = opaque;
 
     assert(vs->magic == VNC_MAGIC);
+
+    if (condition & (G_IO_HUP | G_IO_ERR)) {
+        vnc_disconnect_start(vs);
+        return TRUE;
+    }
+
     if (condition & G_IO_IN) {
         if (vnc_client_read(vs) < 0) {
             /* vs is free()ed here */
@@ -1612,7 +1620,8 @@ void vnc_write(VncState *vs, const void *data, size_t len)
             g_source_remove(vs->ioc_tag);
         }
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_OUT,
+            vnc_client_io, vs, NULL);
     }
 
     buffer_append(&vs->output, data, len);
@@ -3077,14 +3086,17 @@ static void vnc_connect(VncDisplay *vd, QIOChannelSocket *sioc,
         vs->websocket = 1;
         if (vd->tlscreds) {
             vs->ioc_tag = qio_channel_add_watch(
-                vs->ioc, G_IO_IN, vncws_tls_handshake_io, vs, NULL);
+                vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+                vncws_tls_handshake_io, vs, NULL);
         } else {
             vs->ioc_tag = qio_channel_add_watch(
-                vs->ioc, G_IO_IN, vncws_handshake_io, vs, NULL);
+                vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+                vncws_handshake_io, vs, NULL);
         }
     } else {
         vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
+            vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR,
+            vnc_client_io, vs, NULL);
     }
 
     vnc_client_cache_addr(vs);