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path: root/ui/vnc-ws.h
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2015-04-01CVE-2015-1779: incrementally decode websocket framesDaniel P. Berrange1-2/+7
The logic for decoding websocket frames wants to fully decode the frame header and payload, before allowing the VNC server to see any of the payload data. There is no size limit on websocket payloads, so this allows a malicious network client to consume 2^64 bytes in memory in QEMU. It can trigger this denial of service before the VNC server even performs any authentication. The fix is to decode the header, and then incrementally decode the payload data as it is needed. With this fix the websocket decoder will allow at most 4k of data to be buffered before decoding and processing payload. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> [ kraxel: fix frequent spurious disconnects, suggested by Peter Maydell ] @@ -361,7 +361,7 @@ int vncws_decode_frame_payload(Buffer *input, - *payload_size = input->offset; + *payload_size = *payload_remain; [ kraxel: fix 32bit build ] @@ -306,7 +306,7 @@ struct VncState - uint64_t ws_payload_remain; + size_t ws_payload_remain; Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2015-03-18ui: enforce TLS when using websockets serverDaniel P. Berrange1-1/+1
When TLS is required, the primary VNC server considers it to be mandatory. ie the server admin decides whether or not TLS is used, and the client has to comply with this decision. The websockets server, however, treated it as optional, allowing non-TLS clients to connect to a server which had setup TLS. Thus enabling websockets lowers the security of the VNC server leaving the admin no way to enforce use of TLS. This removes the code that allows non-TLS fallback in the websockets server, so that if TLS is requested for VNC it is now mandatory for both the primary VNC server and the websockets VNC server. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-05-03TLS support for VNC WebsocketsTim Hardeck1-0/+3
Added TLS support to the VNC QEMU Websockets implementation. VNC-TLS needs to be enabled for this feature to be used. The required certificates are specified as in case of VNC-TLS with the VNC parameter "x509=<path>". If the server certificate isn't signed by a rooth authority it needs to be manually imported in the browser because at least in case of Firefox and Chrome there is no user dialog, the connection just gets canceled. As a side note VEncrypt over Websocket doesn't work atm because TLS can't be stacked in the current implementation. (It also didn't work before) Nevertheless to my knowledge there is no HTML 5 VNC client which supports it and the Websocket connection can be encrypted with regular TLS now so it should be fine for most use cases. Signed-off-by: Tim Hardeck <thardeck@suse.de> Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Message-id: 1366727581-5772-1-git-send-email-thardeck@suse.de Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-01-21vnc: added initial websocket protocol supportTim Hardeck1-0/+86
This patch adds basic Websocket Protocol version 13 - RFC 6455 - support to QEMU VNC. Binary encoding support on the client side is mandatory. Because of the GnuTLS requirement the Websockets implementation is optional (--enable-vnc-ws). To activate Websocket support the VNC option "websocket"is used, for example "-vnc :0,websocket". The listen port for Websocket connections is (5700 + display) so if QEMU VNC is started with :0 the Websocket port would be 5700. As an alternative the Websocket port could be manually specified by using ",websocket=<port>" instead. Parts of the implementation base on Anthony Liguori's QEMU Websocket patch from 2010 and on Joel Martin's LibVNC Websocket implementation. Signed-off-by: Tim Hardeck <thardeck@suse.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>