| Message ID | 20230705181718.387522-1-berrange@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | io: remove io watch if TLS channel is closed during handshake | expand |
On Wed, Jul 5, 2023 at 10:20 PM Daniel P. Berrangé <berrange@redhat.com> wrote: > 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 <jiangyegen@huawei.com> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> > > --- > 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 9805dd0a3f..e327e6a5c2 100644 > --- a/io/channel-tls.c > +++ b/io/channel-tls.c > @@ -198,12 +198,13 @@ 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); > } > } > > @@ -218,6 +219,7 @@ 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); > > @@ -378,6 +380,10 @@ 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); > set it to 0 ? or g_clear_handle_id(&tios->hs_ioc_tag, g_source_remove); > + } > + > return qio_channel_close(tioc->master, errp); > } > > -- > 2.41.0 > > >
On Fri, Jul 07, 2023 at 01:30:16PM +0400, Marc-André Lureau wrote: > On Wed, Jul 5, 2023 at 10:20 PM Daniel P. Berrangé <berrange@redhat.com> > wrote: > > > 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 <jiangyegen@huawei.com> > > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> > > > > > > > --- > > 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 9805dd0a3f..e327e6a5c2 100644 > > --- a/io/channel-tls.c > > +++ b/io/channel-tls.c > > @@ -198,12 +198,13 @@ 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); > > } > > } > > > > @@ -218,6 +219,7 @@ 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); > > > > @@ -378,6 +380,10 @@ 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); > > > > set it to 0 ? > or > g_clear_handle_id(&tios->hs_ioc_tag, g_source_remove); Yes, close can be called mutliple times, so we must set to zero. > > + } > > + > > return qio_channel_close(tioc->master, errp); > > } > > > > -- > > 2.41.0 > > > > > > > > -- > Marc-André Lureau With regards, Daniel
07.07.2023 12:38, Daniel P. Berrangé wrote: > On Fri, Jul 07, 2023 at 01:30:16PM +0400, Marc-André Lureau wrote: ...>>> @@ -378,6 +380,10 @@ 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); >>> >> >> set it to 0 ? >> or >> g_clear_handle_id(&tios->hs_ioc_tag, g_source_remove); > > Yes, close can be called mutliple times, so we must set to zero. Ping, for qemu 8.1 and -stable ? Thanks, /mjt
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 9805dd0a3f..e327e6a5c2 100644 --- a/io/channel-tls.c +++ b/io/channel-tls.c @@ -198,12 +198,13 @@ 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); } } @@ -218,6 +219,7 @@ 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); @@ -378,6 +380,10 @@ 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); + } + return qio_channel_close(tioc->master, errp); }
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 <jiangyegen@huawei.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- include/io/channel-tls.h | 1 + io/channel-tls.c | 18 ++++++++++++------ 2 files changed, 13 insertions(+), 6 deletions(-)