[Qemu-devel] [PULL 2/9] vnc: Fix qemu crashed when vnc client disconnect suddenly

[Gerd Hoffmann]

From: "Gonglei (Arei)" <address@hidden>

Hi,

When I use RealVNC viewer client (http://www.realvnc.com/) to connect vnc 
server,
the client disconnect suddenly, and I click reconnect button immediately, then 
the Qemu crashed.

In the function vnc_worker_thread_loop, will call vnc_async_encoding_start
to set the local vs->output buffer by global queue's buffer. Then send 
rectangles to
the vnc client call function vnc_send_framebuffer_update. Finally, Under normal 
circumstances,
call vnc_async_encoding_end to set the global queue'buffer by the local 
vs->output conversely.

When the vnc client disconnect, the job->vs->csock will be set to -1. And the 
current prcoess
logic will goto disconnected partion without call function 
vnc_async_encoding_end.
But, the function vnc_send_framebuffer_update will call buffer_reserve, which
maybe call g_realloc reset the local vs's buffer, meaning the global queue's 
buffer is modified also.
If anyone use the original global queue's buffer memory will cause corruption 
and then crash qemu.

This patch assure the function vnc_async_encoding_end being called
even though the vnc client disconnect suddenly.

Signed-off-by: Gonglei <address@hidden>
Signed-off-by: Gerd Hoffmann <address@hidden>
---
 ui/vnc-jobs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/ui/vnc-jobs.c b/ui/vnc-jobs.c
index 2d3fce8..a141f40 100644
--- a/ui/vnc-jobs.c
+++ b/ui/vnc-jobs.c
@@ -252,6 +252,8 @@ static int vnc_worker_thread_loop(VncJobQueue *queue)
 
         if (job->vs->csock == -1) {
             vnc_unlock_display(job->vs->vd);
+            /* Copy persistent encoding data */
+            vnc_async_encoding_end(job->vs, &vs);
             goto disconnected;
         }
 
@@ -278,6 +280,9 @@ static int vnc_worker_thread_loop(VncJobQueue *queue)
         vnc_async_encoding_end(job->vs, &vs);
 
        qemu_bh_schedule(job->vs->bh);
+    }  else {
+        /* Copy persistent encoding data */
+        vnc_async_encoding_end(job->vs, &vs);
     }
     vnc_unlock_output(job->vs);
 
-- 
1.8.3.1