[tor-commits] [flashproxy/master] Checking if the proxy is running in a Tor Proxy and disabling itelf.

[dcf at torproject.org]

commit 006708e921a1a93cbc619c6993c30404857d7bcf
Author: Jorge Couchet <jorge.couchet at gmail.com>
Date:   Thu Nov 22 13:08:36 2012 +0100

    Checking if the proxy is running in a Tor Proxy and disabling itelf.
---
 proxy/flashproxy.js |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/proxy/flashproxy.js b/proxy/flashproxy.js
index 2078b69..435b8ea 100644
--- a/proxy/flashproxy.js
+++ b/proxy/flashproxy.js
@@ -865,6 +865,23 @@ function repr(x) {
     }
 }
 
+/* The function is trying to detect that the proxy is running in a Tor Browser. A Tor Browser has
+   an specific 'navigator.userAgent' string, it is also entirely disabling the DOM storage and
+   not listing the supported MIME types.
+
+   https://trac.torproject.org/projects/tor/ticket/6293
+
+*/
+function is_likely_tor_browser() {
+
+        var isTB = false;
+
+        if ( (navigator.userAgent == "Mozilla/5.0 (Windows NT 6.1; rv:10.0) Gecko/20100101 Firefox/10.0") && (sessionStorage === null) && (navigator.mimeTypes.length == 0) )
+          isTB = true;
+
+        return isTB;
+}
+
 /* Are circumstances such that we should self-disable and not be a
    proxy? We take a best-effort guess as to whether this device runs on
    a battery or the data transfer might be expensive.
@@ -876,6 +893,13 @@ function repr(x) {
 function flashproxy_should_disable() {
     var ua;
 
+    /* If the proxy is running in a Tor Browser there is a possible security problem:
+          It is reported at: https://trac.torproject.org/projects/tor/ticket/6293  */
+    if (is_likely_tor_browser()) {
+         puts("Disable because is running in a Tor Browser.");
+         return true;
+    }
+
     ua = window.navigator.userAgent;
     if (ua !== null) {
         var UA_LIST = [