From 2815cc73cfd9d8ced889e00e72899708220d184f Mon Sep 17 00:00:00 2001
From: Louis Lam <louislam@users.noreply.github.com>
Date: Sun, 10 Dec 2023 20:39:43 +0800
Subject: [PATCH] Merge pull request from GHSA-mj22-23ff-2hrr

* WIP

* WIP

* Handle parsing error

* Fix matching origin issue
---
 server/server.js             |  5 +++++
 server/uptime-kuma-server.js | 38 ++++++++++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/server/server.js b/server/server.js
index 13dd1601..11174f76 100644
--- a/server/server.js
+++ b/server/server.js
@@ -48,8 +48,13 @@ if (! process.env.NODE_ENV) {
     process.env.NODE_ENV = "production";
 }
 
+if (!process.env.UPTIME_KUMA_WS_ORIGIN_CHECK) {
+    process.env.UPTIME_KUMA_WS_ORIGIN_CHECK = "cors-like";
+}
+
 log.info("server", "Node Env: " + process.env.NODE_ENV);
 log.info("server", "Inside Container: " + (process.env.UPTIME_KUMA_IS_CONTAINER === "1"));
+log.info("server", "WebSocket Origin Check: " + process.env.UPTIME_KUMA_WS_ORIGIN_CHECK);
 
 log.info("server", "Importing Node libraries");
 const fs = require("fs");
diff --git a/server/uptime-kuma-server.js b/server/uptime-kuma-server.js
index 28df6461..07dfc30f 100644
--- a/server/uptime-kuma-server.js
+++ b/server/uptime-kuma-server.js
@@ -4,7 +4,7 @@ const fs = require("fs");
 const http = require("http");
 const { Server } = require("socket.io");
 const { R } = require("redbean-node");
-const { log } = require("../src/util");
+const { log, isDev } = require("../src/util");
 const Database = require("./database");
 const util = require("util");
 const { CacheableDnsHttpAgent } = require("./cacheable-dns-http-agent");
@@ -103,7 +103,41 @@ class UptimeKumaServer {
         UptimeKumaServer.monitorTypeList["real-browser"] = new RealBrowserMonitorType();
         UptimeKumaServer.monitorTypeList["tailscale-ping"] = new TailscalePing();
 
-        this.io = new Server(this.httpServer);
+        this.io = new Server(this.httpServer, {
+            allowRequest: (req, callback) => {
+                let isOriginValid = true;
+                const bypass = isDev || process.env.UPTIME_KUMA_WS_ORIGIN_CHECK === "bypass";
+
+                if (!bypass) {
+                    let host = req.headers.host;
+
+                    // If this is set, it means the request is from the browser
+                    let origin = req.headers.origin;
+
+                    // If this is from the browser, check if the origin is allowed
+                    if (origin) {
+                        try {
+                            let originURL = new URL(origin);
+
+                            if (host !== originURL.host) {
+                                isOriginValid = false;
+                                log.error("auth", `Origin (${origin}) does not match host (${host}), IP: ${req.socket.remoteAddress}`);
+                            }
+                        } catch (e) {
+                            // Invalid origin url, probably not from browser
+                            isOriginValid = false;
+                            log.error("auth", `Invalid origin url (${origin}), IP: ${req.socket.remoteAddress}`);
+                        }
+                    } else {
+                        log.info("auth", `Origin is not set, IP: ${req.socket.remoteAddress}`);
+                    }
+                } else {
+                    log.debug("auth", "Origin check is bypassed");
+                }
+
+                callback(null, isOriginValid);
+            }
+        });
     }
 
     /** Initialise app after the database has been set up */