Initial IP session cookie implementation

src/io/ioserver.js

@@ -15,6 +15,7 @@ var crypto = require("crypto");
 var isTorExit = require("../tor").isTorExit;
 var session = require("../session");
 import counters from '../counters';
+import { verifyIPSessionCookie } from '../web/middleware/ipsessioncookie';
 
 var CONNECT_RATE = {
     burst: 5,
@@ -25,16 +26,24 @@ var ipThrottle = {};
 // Keep track of number of connections per IP
 var ipCount = {};
 
+function parseCookies(socket, accept) {
+    var req = socket.request;
+    if (req.headers.cookie) {
+        cookieParser(req, null, () => {
+            accept(null, true);
+        });
+    } else {
+        req.cookies = {};
+        req.signedCookies = {};
+        accept(null, true);
+    }
+}
 /**
  * Called before an incoming socket.io connection is accepted.
  */
 function handleAuth(socket, accept) {
-    var data = socket.request;
-
     socket.user = false;
-    if (data.headers.cookie) {
-        cookieParser(data, null, function () {
-            var auth = data.signedCookies.auth;
+    var auth = socket.request.signedCookies.auth;
     if (!auth) {
         return accept(null, true);
     }
@@ -48,10 +57,22 @@ function handleAuth(socket, accept) {
         }
         accept(null, true);
     });
-        });
-    } else {
-        accept(null, true);
+}
+
+function handleIPSessionCookie(socket, accept) {
+    var cookie = socket.request.signedCookies['ip-session'];
+    if (!cookie) {
+        socket.ipSessionFirstSeen = new Date();
+        return accept(null, true);
     }
+
+    var sessionMatch = verifyIPSessionCookie(socket._realip, cookie);
+    if (sessionMatch) {
+        socket.ipSessionFirstSeen = sessionMatch.date;
+    } else {
+        socket.ipSessionFirstSeen = new Date();
+    }
+    accept(null, true);
 }
 
 function throttleIP(sock) {
@@ -247,8 +268,10 @@ module.exports = {
         };
         var io = sio.instance = sio();
 
-        io.use(handleAuth);
         io.use(ipForwardingMiddleware(webConfig));
+        io.use(parseCookies);
+        io.use(handleIPSessionCookie);
+        io.use(handleAuth);
         io.on("connection", handleConnection);
 
         Config.get("listen").forEach(function (bind) {

src/server.js

@@ -18,6 +18,11 @@ module.exports = {
             exists || fs.mkdir(chandumppath);
         });
 
+        var statepath = path.join(__dirname, "../state");
+        fs.exists(statepath, function (exists) {
+            exists || fs.mkdir(statepath);
+        });
+
         var gdvttpath = path.join(__dirname, "../google-drive-subtitles");
         fs.exists(gdvttpath, function (exists) {
             exists || fs.mkdir(gdvttpath);

src/web/middleware/ipsessioncookie.js

@@ -0,0 +1,76 @@
+import path from 'path';
+import fs from 'fs';
+import crypto from 'crypto';
+
+const SALT_PATH = path.resolve(__dirname, '..', '..', '..', 'state', 'ipsessionsalt.json');
+
+var SALT;
+try {
+    SALT = require(SALT_PATH);
+} catch (error) {
+    SALT = crypto.randomBytes(32).toString('base64');
+    fs.writeFileSync(SALT_PATH, SALT);
+}
+
+function sha256(input) {
+    var hash = crypto.createHash("sha256");
+    hash.update(input);
+    return hash.digest("base64");
+}
+
+export function createIPSessionCookie(ip, date) {
+    const hashInput = [
+        ip,
+        date.getTime(),
+        SALT
+    ].join(':');
+
+    return [
+        date.getTime(),
+        sha256(hashInput)
+    ].join(':');
+}
+
+export function verifyIPSessionCookie(ip, cookie) {
+    const parts = cookie.split(':');
+    if (parts.length !== 2) {
+        return false;
+    }
+
+    const timestamp = parseInt(parts[0], 10);
+    if (isNaN(timestamp)) {
+        return false;
+    }
+
+    const date = new Date(timestamp);
+    const expected = createIPSessionCookie(ip, date);
+    if (expected !== cookie) {
+        return false;
+    }
+
+    return {
+        date: date,
+    };
+}
+
+export function ipSessionCookieMiddleware(req, res, next) {
+    var firstSeen = new Date();
+    var hasSession = false;
+    if (req.signedCookies && req.signedCookies['ip-session']) {
+        var sessionMatch = verifyIPSessionCookie(req.realIP, req.signedCookies['ip-session']);
+        if (sessionMatch) {
+            hasSession = true;
+            firstSeen = sessionMatch.date;
+        }
+    }
+
+    if (!hasSession) {
+        res.cookie('ip-session', createIPSessionCookie(req.realIP, firstSeen), {
+            signed: true,
+            httpOnly: true
+        });
+    }
+
+    req.ipSessionFirstSeen = firstSeen;
+    next();
+}

src/web/webserver.js

@@ -146,6 +146,7 @@ module.exports = {
         }
         app.use(cookieParser(webConfig.getCookieSecret()));
         app.use(csrf.init(webConfig.getCookieDomain()));
+        app.use('/r/:channel', require('./middleware/ipsessioncookie').ipSessionCookieMiddleware);
         initializeLog(app);
         require('./middleware/authorize')(app, session);