From 3eca3cc3ce4c5553680ca3bab533443460c570d6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Tue, 20 Jun 2023 09:45:34 +0100
Subject: [PATCH] io: remove io watch if TLS channel is closed during handshake
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The TLS handshake make take some time to complete, during which time an
I/O watch might be registered with the main loop. If the owner of the
I/O channel invokes qio_channel_close() while the handshake is waiting
to continue the I/O watch must be removed. Failing to remove it will
later trigger the completion callback which the owner is not expecting
to receive. In the case of the VNC server, this results in a SEGV as
vnc_disconnect_start() tries to shutdown a client connection that is
already gone / NULL.

---------------------------------------------------------------------
Note: g_clear_handle_id is not available before glibc-2.56, modify it.

CVE-2023-3354
Reported-by: jiangyegen <jiangyegen@huawei.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 include/io/channel-tls.h |  1 +
 io/channel-tls.c         | 19 +++++++++++++------
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/io/channel-tls.h b/include/io/channel-tls.h
index fdbdf12feb..e49e2831a2 100644
--- a/include/io/channel-tls.h
+++ b/include/io/channel-tls.h
@@ -49,6 +49,7 @@ struct QIOChannelTLS {
     QIOChannel *master;
     QCryptoTLSSession *session;
     QIOChannelShutdown shutdown;
+    guint hs_ioc_tag;
 };
 
 /**
diff --git a/io/channel-tls.c b/io/channel-tls.c
index 7ec8ceff2f..b0bdbd428f 100644
--- a/io/channel-tls.c
+++ b/io/channel-tls.c
@@ -194,12 +194,13 @@ static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc,
         }
 
         trace_qio_channel_tls_handshake_pending(ioc, status);
-        qio_channel_add_watch_full(ioc->master,
-                                   condition,
-                                   qio_channel_tls_handshake_io,
-                                   data,
-                                   NULL,
-                                   context);
+        ioc->hs_ioc_tag =
+            qio_channel_add_watch_full(ioc->master,
+                                       condition,
+                                       qio_channel_tls_handshake_io,
+                                       data,
+                                       NULL,
+                                       context);
     }
 }
 
@@ -214,6 +215,7 @@ static gboolean qio_channel_tls_handshake_io(QIOChannel *ioc,
     QIOChannelTLS *tioc = QIO_CHANNEL_TLS(
         qio_task_get_source(task));
 
+    tioc->hs_ioc_tag = 0;
     g_free(data);
     qio_channel_tls_handshake_task(tioc, task, context);
 
@@ -371,6 +373,11 @@ static int qio_channel_tls_close(QIOChannel *ioc,
 {
     QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
 
+    if (tioc->hs_ioc_tag) {
+        g_source_remove(tioc->hs_ioc_tag);
+        tioc->hs_ioc_tag = 0;
+    }
+
     return qio_channel_close(tioc->master, errp);
 }
 
-- 
2.41.0.windows.1

