ctf-3

Author: JVancata

.env.docker.example

@@ -2,4 +2,5 @@
 SOUNDBOARD_API_URL="http://localhost:3000"
 STEAM_STICKERS_API_CACHE_PATH="/mnt/steam-stickers-cache"
 CTF_1_FLAG="CTF_1_FLAG"
-CTF_2_FLAG="CTF_2_FLAG"
+CTF_2_FLAG="CTF_2_FLAG"
+CTF_3_FLAG="CTF_3_FLAG"

apps/ctf-3/.env.example

@@ -0,0 +1,2 @@
+# Rename this file to .env
+CTF_3_FLAG="PROSEK{neleakuj_si_secrets_do_gitu_lol_minimalne_je_pak_zrotuj}"

apps/ctf-3/Dockerfile

@@ -0,0 +1,11 @@
+FROM node:24.8-alpine
+
+ENV NODE_ENV=production
+
+COPY package.json .
+RUN npm install
+
+COPY . .
+
+CMD ["node", "index.ts"]
+EXPOSE 3000

apps/ctf-3/index.ts

@@ -0,0 +1,40 @@
+import express from 'express'
+import cors from 'cors'
+
+const app = express()
+const port = 3000
+
+app.use(cors())
+app.use(express.json());
+
+const FLAG = process.env.CTF_3_FLAG;
+
+if (!FLAG) {
+    console.error("No CTF_3_FLAG .env value specified! Killing process...");
+    process.exit(1);
+}
+
+app.get('/', (_request, response) => {
+    response.send('Poslal*a si GET request. Musíš poslat POST request s tělem { "input": "string" }, aby si ověřil*a vlajku.');
+})
+
+app.post('/', (request, response) => {
+    const input = request.body.input;
+
+    if (!input || !(typeof input === "string")) {
+        response.send('Tělo musí být { "input": "string" }, aby si ověřil*a vlajku.');
+        return;
+    };
+
+    if (input === FLAG) {
+        response.send(`✅ Výborně!`);
+        return;
+    }
+
+    response.send(`❌ Zkoušej to dál...`);
+    return;
+})
+
+app.listen(port, () => {
+    console.log(`ctf-3 running on port ${port}`)
+})

apps/ctf-3/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "ctf-3",
+  "version": "1.0.0",
+  "main": "index.ts",
+  "type": "module",
+  "scripts": {
+    "dev": "node --watch --experimental-strip-types --env-file=.env index.ts",
+    "docker:build": "docker build -t ctf-3 .",
+    "docker:run": "docker run -p 3000:3000 ctf-3"
+  },
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "cors": "^2.8.5",
+    "express": "^5.1.0"
+  },
+  "devDependencies": {
+    "@types/cors": "^2.8.18",
+    "@types/express": "^5.0.2"
+  }
+}

compose.yaml

@@ -56,5 +56,12 @@ services:
     ports:
       - "3007:80"
 
+  ctf-3:
+    build: apps/ctf-3
+    environment:
+      CTF_3_FLAG: $CTF_3_FLAG
+    ports:
+      - "3008:3000"
+
 volumes:
   steam-stickers-cache:

nginx.config

@@ -86,6 +86,16 @@ server {
         proxy_cache_bypass $http_upgrade;  
     }
 
+    # The trailing slash must not be here because of the weird proxying behavior
+    location /ctf-3 {
+	    proxy_pass http://localhost:3008/;
+        proxy_http_version 1.1;  
+        proxy_set_header Upgrade $http_upgrade;  
+        proxy_set_header Connection 'upgrade';  
+        proxy_set_header Host $host;  
+        proxy_cache_bypass $http_upgrade;  
+    }
+
     listen [::]:443 ssl ipv6only=on; # managed by Certbot
     listen 443 ssl; # managed by Certbot
     ssl_certificate /etc/letsencrypt/live/materialy.jakub.dev/fullchain.pem; # managed by Certbot