feat: added captcha serving service to haproxy

README.MD

@@ -0,0 +1,19 @@
+## HaProxy DDoS protection system PoC
+
+If there is an unusual HTTP requests flow to a specific domain, the system detects it and triggers DDoS protection mode.
+Each new client will be first forced to complete hCaptcha, before proceeding to the website.
+
+
+##### How to test
+
+- export hcaptcha sitekey and secret:
+```bash
+export HCAPTCHA_SITEKEY=xxxXXxxx
+export HCAPTCHA_SECRET=xxxXXxxx
+```
+- run docker compose:
+```bash
+docker compose up
+```
+
+- visit *http://127.0.0.1/captcha*

docker-compose.yml

@@ -9,6 +9,9 @@ services:
     volumes:
       - ./haproxy/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg
       - ./scripts/:/usr/local/etc/haproxy/scripts/
+    environment:
+      - HCAPTCHA_SECRET=${HCAPTCHA_SECRET}
+      - HCAPTCHA_SITEKEY=${HCAPTCHA_SITEKEY}
 
   nginx:
     image: "nginx:latest"

haproxy/Dockerfile

@@ -95,8 +95,26 @@ STOPSIGNAL SIGUSR1
 
 ADD haproxy/docker-entrypoint.sh /usr/local/bin/
 RUN ln -s usr/local/bin/docker-entrypoint.sh / # backwards compat
-RUN apt-get update && apt-get install luarocks -y
-RUN luarocks install luasocket
+
+# This is terrible mess but we need it for simple testing purposes of our POC
+RUN apt-get update && apt-get install libssl-dev make nano wget gcc libreadline-dev unzip git -y
+RUN wget http://www.lua.org/ftp/lua-5.3.5.tar.gz &&\
+    tar -zxf lua-5.3.5.tar.gz &&\
+    cd lua-5.3.5 &&\
+    make linux test &&\
+    make install
+
+RUN wget "https://luarocks.org/releases/luarocks-3.3.1.tar.gz" &&\
+    tar zxpf luarocks-3.3.1.tar.gz &&\
+    cd luarocks-3.3.1 &&\
+    ./configure --with-lua-include=/usr/local/include --lua-version=5.3 --lua-suffix=5.3 &&\
+    make &&\
+    make install
+
+RUN /usr/local/bin/luarocks install luasocket &&\
+    /usr/local/bin/luarocks install luasec &&\
+    /usr/local/bin/luarocks install net-url
+
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
 
 # no USER for backwards compatibility (to try to avoid breaking existing users)

haproxy/haproxy.cfg

@@ -15,6 +15,7 @@ frontend http-in
     default_backend servers
     # http-request lua.test-payload
     http-request use-service lua.hello-world   if { path /hello_world }
+    http-request use-service lua.hcaptcha-view   if { path /captcha }
 
 backend servers
     server server1 nginx:80 maxconn 32

scripts/hcaptcha.lua

@@ -0,0 +1,51 @@
+hcaptcha = {}
+
+local url = require("net.url")
+local https = require("ssl.https")
+local json = require("json")
+
+function hcaptcha.view(applet)
+    local hcaptcha_secret = os.getenv("HCAPTCHA_SECRET")
+    local hcaptcha_sitekey = os.getenv("HCAPTCHA_SITEKEY")
+
+    local response
+    if applet.method == "GET" then
+        response =
+            [[
+        <form method="POST">
+        <div class="h-captcha" data-sitekey="%s"></div>
+        <script src="https://hcaptcha.com/1/api.js" async defer></script>
+        <input type="submit" value="Submit">
+        </form>
+        ]]
+        response = string.format(response, hcaptcha_sitekey)
+    elseif applet.method == "POST" then
+        local parsed_body = url.parseQuery(applet.receive(applet))
+
+        if parsed_body["h-captcha-response"] then
+            local url =
+                string.format(
+                "https://hcaptcha.com/siteverify?secret=%s&response=%s",
+                hcaptcha_secret,
+                parsed_body["h-captcha-response"]
+            )
+            local body, code, headers, status = https.request(url)
+            local api_response = json:decode(body)
+
+            if api_response.success == true then
+                print("HCAPTCHA SUCCESSFULLY PASSED")
+                print("... success captcha flow goes here ...")
+            else
+                print("HCAPTCHA FAILED", body)
+            end
+        end
+
+        response = "Thank you for submitting"
+    end
+
+    applet:set_status(200)
+    applet:add_header("content-type", "text/html")
+    applet:add_header("content-length", string.len(response))
+    applet:start_response()
+    applet:send(response)
+end

scripts/register.lua

@@ -1,5 +1,7 @@
 package.path = package.path  .. "./?.lua;/usr/local/etc/haproxy/scripts/?.lua"
 
 require("guard")
+require("hcaptcha")
 
-core.register_service("hello-world", "http", guard.hello_world);
+core.register_service("hello-world", "http", guard.hello_world)
+core.register_service("hcaptcha-view", "http", hcaptcha.view)