From 62a58c5c2ab8ae7575a9d91d903e97ef250cc537 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 20 Apr 2018 10:48:19 +0200
Subject: [PATCH] vnc: fix use-after-free
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When vnc_client_read() return value is -1
vs is not valid any more.

Fixes: d49b87f0d1e0520443a990fc610d0f02bc63c556
Reported-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180420084820.3873-1-kraxel@redhat.com
(cherry picked from commit 1bc3117abad28d6465ecdb2c944b22943df0e4f3)
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 ui/vnc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index 5ebae6f664..a4b2cc7666 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -1539,13 +1539,14 @@ gboolean vnc_client_io(QIOChannel *ioc G_GNUC_UNUSED,
     VncState *vs = opaque;
     if (condition & G_IO_IN) {
         if (vnc_client_read(vs) < 0) {
-            goto end;
+            /* vs is free()ed here */
+            return TRUE;
         }
     }
     if (condition & G_IO_OUT) {
         vnc_client_write(vs);
     }
-end:
+
     if (vs->disconnecting) {
         if (vs->ioc_tag != 0) {
             g_source_remove(vs->ioc_tag);