From 10be627d2b5ec2d6b3dce045144aa739eef678b4 Mon Sep 17 00:00:00 2001 From: Daniel P. Berrangé Date: Tue, 12 Sep 2023 06:38:03 +0000 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 CVE: CVE-2023-3354 Upstream-Status: Backport [https://gitlab.com/qemu-project/qemu/-/commit/10be627d2b5ec2d6b3dce045144aa739eef678b4] Signed-off-by: Yogita Urade --- 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 5672479e9..ccd510ade 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 4ce890a53..17d73f02e 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); } -- 2.35.5