From b722a90334c09586b54c3e18ce6e2b492521c6ef Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Tue, 20 Jun 2023 09:45:34 +0100 Subject: [PATCH] io: remove io watch if TLS channel is closed during handshake MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. CVE-2023-3354 Reported-by: jiangyegen Signed-off-by: Daniel P. Berrangé Signed-off-by: zeng_chi --- include/io/channel-tls.h | 1 + io/channel-tls.c | 18 ++++++++++++------ 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/include/io/channel-tls.h b/include/io/channel-tls.h index 5672479e9e..26c67f17e2 100644 --- a/include/io/channel-tls.h +++ b/include/io/channel-tls.h @@ -48,6 +48,7 @@ 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 4ce890a538..e1e6c11e03 100644 --- a/io/channel-tls.c +++ b/io/channel-tls.c @@ -195,12 +195,13 @@ 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); } } @@ -215,6 +216,7 @@ 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); @@ -374,6 +376,10 @@ static int qio_channel_tls_close(QIOChannel *ioc, { QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc); + if (tioc->hs_ioc_tag) { + g_clear_handle_id(&tioc->hs_ioc_tag, g_source_remove); + } + return qio_channel_close(tioc->master, errp); }