ui: enforce TLS when using websockets server

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 <[email protected]> Signed-off-by: Gerd Hoffmann <[email protected]>
fatenever · Mar 18, 2015 · 51941e4 · 51941e4
1 parent f9148c8
commit 51941e4
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Showing 3 changed files with 9 additions and 26 deletions.
diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c
@@ -24,8 +24,6 @@
 #ifdef CONFIG_VNC_TLS
 #include "qemu/sockets.h"
 
-static void vncws_tls_handshake_io(void *opaque);
-
 static int vncws_start_tls_handshake(struct VncState *vs)
 {
     int ret = gnutls_handshake(vs->ws_tls.session);
@@ -53,33 +51,18 @@ static int vncws_start_tls_handshake(struct VncState *vs)
     return 0;
 }
 
-static void vncws_tls_handshake_io(void *opaque)
+void vncws_tls_handshake_io(void *opaque)
 {
     struct VncState *vs = (struct VncState *)opaque;
 
-    VNC_DEBUG("Handshake IO continue\n");
-    vncws_start_tls_handshake(vs);
-}
-
-void vncws_tls_handshake_peek(void *opaque)
-{
-    VncState *vs = opaque;
-    long ret;
-
-    if (!vs->ws_tls.session) {
-        char peek[4];
-        ret = qemu_recv(vs->csock, peek, sizeof(peek), MSG_PEEK);
-        if (ret && (strncmp(peek, "\x16", 1) == 0
-                    || strncmp(peek, "\x80", 1) == 0)) {
-            VNC_DEBUG("TLS Websocket connection recognized");
-            vnc_tls_client_setup(vs, 1);
-            vncws_start_tls_handshake(vs);
-        } else {
-            vncws_handshake_read(vs);
+    if (!vs->tls.session) {
+        VNC_DEBUG("TLS Websocket setup\n");
+        if (vnc_tls_client_setup(vs, vs->vd->tls.x509cert != NULL) < 0) {
+            return;
         }
-    } else {
-        qemu_set_fd_handler2(vs->csock, NULL, vncws_handshake_read, NULL, vs);
     }
+    VNC_DEBUG("Handshake IO continue\n");
+    vncws_start_tls_handshake(vs);
 }
 #endif /* CONFIG_VNC_TLS */
 

diff --git a/ui/vnc-ws.h b/ui/vnc-ws.h
@@ -75,7 +75,7 @@ enum {
 };
 
 #ifdef CONFIG_VNC_TLS
-void vncws_tls_handshake_peek(void *opaque);
+void vncws_tls_handshake_io(void *opaque);
 #endif /* CONFIG_VNC_TLS */
 void vncws_handshake_read(void *opaque);
 long vnc_client_write_ws(VncState *vs);

diff --git a/ui/vnc.c b/ui/vnc.c
@@ -3036,7 +3036,7 @@ static void vnc_connect(VncDisplay *vd, int csock,
         vs->websocket = 1;
 #ifdef CONFIG_VNC_TLS
         if (vd->ws_tls) {
-            qemu_set_fd_handler2(vs->csock, NULL, vncws_tls_handshake_peek,
+            qemu_set_fd_handler2(vs->csock, NULL, vncws_tls_handshake_io,
                                  NULL, vs);
         } else
 #endif /* CONFIG_VNC_TLS */