mirror of
https://gitgud.io/fatchan/haproxy-protection.git
synced 2025-05-09 02:05:37 +00:00
Reorganise, move code to not be split between haproxy and src folder
This commit is contained in:
Thomas Lynch
358
src/lua/scripts/bot-check.lua
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358
src/lua/scripts/bot-check.lua
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@ -0,0 +1,358 @@
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_M = {}
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-- Testing only
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-- require("socket")
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-- require("print_r")
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-- main libs
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local url = require("url")
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local utils = require("utils")
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local cookie = require("cookie")
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local json = require("json")
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local sha = require("sha")
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local randbytes = require("randbytes")
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local templates = require("templates")
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-- POW
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local pow_difficulty = tonumber(os.getenv("POW_DIFFICULTY") or 18)
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-- argon2
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local argon2 = require("argon2")
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local argon_kb = tonumber(os.getenv("ARGON_KB") or 6000)
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local argon_time = tonumber(os.getenv("ARGON_TIME") or 1)
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argon2.t_cost(argon_time)
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argon2.m_cost(argon_kb)
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argon2.parallelism(1)
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argon2.hash_len(32)
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argon2.variant(argon2.variants.argon2_id)
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-- sha2
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-- TODO
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-- environment variables
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local captcha_secret = os.getenv("HCAPTCHA_SECRET") or os.getenv("RECAPTCHA_SECRET")
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local captcha_sitekey = os.getenv("HCAPTCHA_SITEKEY") or os.getenv("RECAPTCHA_SITEKEY")
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local captcha_cookie_secret = os.getenv("CAPTCHA_COOKIE_SECRET")
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local pow_cookie_secret = os.getenv("POW_COOKIE_SECRET")
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local hmac_cookie_secret = os.getenv("HMAC_COOKIE_SECRET")
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local ray_id = os.getenv("RAY_ID")
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-- load captcha map and set hcaptcha/recaptch based off env vars
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local captcha_map = Map.new("/etc/haproxy/ddos.map", Map._str);
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local captcha_provider_domain = ""
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local captcha_classname = ""
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local captcha_script_src = ""
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local captcha_siteverify_path = ""
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local captcha_backend_name = ""
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if os.getenv("HCAPTCHA_SITEKEY") then
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captcha_provider_domain = "hcaptcha.com"
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captcha_classname = "h-captcha"
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captcha_script_src = "https://hcaptcha.com/1/api.js"
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captcha_siteverify_path = "/siteverify"
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captcha_backend_name = "hcaptcha"
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else
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captcha_provider_domain = "www.google.com"
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captcha_classname = "g-recaptcha"
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captcha_script_src = "https://www.google.com/recaptcha/api.js"
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captcha_siteverify_path = "/recaptcha/api/siteverify"
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captcha_backend_name = "recaptcha"
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end
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-- setup initial server backends based on hosts.map into backends.map
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function _M.setup_servers()
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if pow_difficulty < 8 then
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error("POW_DIFFICULTY must be > 8. Around 16-32 is better")
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end
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local backend_name = os.getenv("BACKEND_NAME")
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local server_prefix = os.getenv("SERVER_PREFIX")
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if backend_name == nil or server_prefix == nil then
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return;
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end
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local hosts_map = Map.new("/etc/haproxy/hosts.map", Map._str);
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local handle = io.open("/etc/haproxy/hosts.map", "r")
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local line = handle:read("*line")
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local counter = 1
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while line do
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local domain, backend_host = line:match("([^%s]+)%s+([^%s]+)")
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local port_index = backend_host:match'^.*():'
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local backend_hostname = backend_host:sub(0, port_index-1)
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local backend_port = backend_host:sub(port_index + 1)
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core.set_map("/etc/haproxy/backends.map", domain, server_prefix..counter)
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local proxy = core.proxies[backend_name].servers[server_prefix..counter]
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proxy:set_addr(backend_hostname, backend_port)
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proxy:set_ready()
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line = handle:read("*line")
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counter = counter + 1
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end
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handle:close()
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end
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-- kill a tor circuit
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function _M.kill_tor_circuit(txn)
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local ip = txn.sf:src()
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if ip:sub(1,19) ~= "fc00:dead:beef:4dad" then
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return -- not a tor circuit id/ip. we shouldn't get here, but just in case.
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end
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-- split the IP, take the last 2 sections
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local split_ip = utils.split(ip, ":")
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local aa_bb = split_ip[5] or "0000"
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local cc_dd = split_ip[6] or "0000"
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aa_bb = string.rep("0", 4 - #aa_bb) .. aa_bb
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cc_dd = string.rep("0", 4 - #cc_dd) .. cc_dd
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-- convert the last 2 sections to a number from hex, which makes the circuit ID
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local circuit_identifier = tonumber(aa_bb..cc_dd, 16)
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print('Closing Tor circuit ID: '..circuit_identifier..', "IP": '..ip)
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utils.send_tor_control_port(circuit_identifier)
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end
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function _M.view(applet)
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-- set response body and declare status code
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local response_body = ""
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local response_status_code
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-- if request is GET, serve the challenge page
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if applet.method == "GET" then
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-- get the user_key#challenge#sig
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local user_key = sha.bin_to_hex(randbytes(16))
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local challenge_hash = utils.generate_secret(applet, pow_cookie_secret, user_key, true)
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local signature = sha.hmac(sha.sha3_256, hmac_cookie_secret, user_key .. challenge_hash)
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local combined_challenge = user_key .. "#" .. challenge_hash .. "#" .. signature
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-- define body sections
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local site_name_body = ""
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local captcha_body = ""
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local pow_body = ""
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local noscript_extra_body = ""
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-- check if captcha is enabled, path+domain priority, then just domain, and 0 otherwise
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local captcha_enabled = false
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local host = applet.headers['host'][0]
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local path = applet.qs; --because on /.basedflare/bot-check?/whatever, .qs (query string) holds the "path"
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local captcha_map_lookup = captcha_map:lookup(host..path) or captcha_map:lookup(host) or 0
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captcha_map_lookup = tonumber(captcha_map_lookup)
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if captcha_map_lookup == 2 then
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captcha_enabled = true
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end
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-- pow at least is always enabled when reaching bot-check page
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site_name_body = string.format(templates.site_name_section, host)
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if captcha_enabled then
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captcha_body = string.format(templates.captcha_section, captcha_classname,
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captcha_sitekey, captcha_script_src)
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else
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pow_body = templates.pow_section
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noscript_extra_body = string.format(templates.noscript_extra, user_key, challenge_hash, signature,
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math.ceil(pow_difficulty/8), argon_time, argon_kb)
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end
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-- sub in the body sections
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response_body = string.format(templates.body, combined_challenge,
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pow_difficulty, argon_time, argon_kb,
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site_name_body, pow_body, captcha_body, noscript_extra_body, ray_id)
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response_status_code = 403
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-- if request is POST, check the answer to the pow/cookie
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elseif applet.method == "POST" then
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-- if they fail, set a var for use in ACLs later
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local valid_submission = false
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-- parsed POST body
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local parsed_body = url.parseQuery(applet.receive(applet))
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-- whether to set cookies sent as secure or not
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local secure_cookie_flag = " Secure=true;"
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if applet.sf:ssl_fc() == "0" then
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secure_cookie_flag = ""
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end
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-- handle setting the POW cookie
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local user_pow_response = parsed_body["pow_response"]
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if user_pow_response then
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-- split the response up (makes the nojs submission easier because it can be a single field)
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local split_response = utils.split(user_pow_response, "#")
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if #split_response == 4 then
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local given_user_key = split_response[1]
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local given_challenge_hash = split_response[2]
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local given_signature = split_response[3]
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local given_answer = split_response[4]
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-- regenerate the challenge and compare it
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local generated_challenge_hash = utils.generate_secret(applet, pow_cookie_secret, given_user_key, true)
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if given_challenge_hash == generated_challenge_hash then
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-- regenerate the signature and compare it
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local generated_signature = sha.hmac(sha.sha3_256, hmac_cookie_secret, given_user_key .. given_challenge_hash)
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if given_signature == generated_signature then
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-- do the work with their given answer
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local full_hash = argon2.hash_encoded(given_challenge_hash .. given_answer, given_user_key)
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-- check the output is correct
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local hash_output = utils.split(full_hash, '$')[6]:sub(0, 43) -- https://github.com/thibaultcha/lua-argon2/issues/37
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local hex_hash_output = sha.bin_to_hex(sha.base64_to_bin(hash_output));
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if utils.checkdiff(hex_hash_output, pow_difficulty) then
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-- the answer was good, give them a cookie
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local signature = sha.hmac(sha.sha3_256, hmac_cookie_secret, given_user_key .. given_challenge_hash .. given_answer)
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local combined_cookie = given_user_key .. "#" .. given_challenge_hash .. "#" .. given_answer .. "#" .. signature
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applet:add_header(
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"set-cookie",
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string.format(
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"z_ddos_pow=%s; Expires=Thu, 31-Dec-37 23:55:55 GMT; Path=/; Domain=.%s; SameSite=Strict;%s",
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combined_cookie,
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applet.headers['host'][0],
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secure_cookie_flag
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)
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)
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valid_submission = true
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end
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end
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end
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end
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end
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-- handle setting the captcha cookie
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local user_captcha_response = parsed_body["h-captcha-response"] or parsed_body["g-recaptcha-response"]
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if valid_submission and user_captcha_response then -- only check captcha if POW is already correct
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-- format the url for verifying the captcha response
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local captcha_url = string.format(
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"https://%s%s",
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core.backends[captcha_backend_name].servers[captcha_backend_name]:get_addr(),
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captcha_siteverify_path
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)
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-- construct the captcha body to send to the captcha url
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local captcha_body = url.buildQuery({
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secret=captcha_secret,
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response=user_captcha_response
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})
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-- instantiate an http client and make the request
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local httpclient = core.httpclient()
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local res = httpclient:post{
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url=captcha_url,
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body=captcha_body,
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headers={
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[ "host" ] = { captcha_provider_domain },
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[ "content-type" ] = { "application/x-www-form-urlencoded" }
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}
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}
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-- try parsing the response as json
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local status, api_response = pcall(json.decode, res.body)
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if not status then
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api_response = {}
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end
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-- the response was good i.e the captcha provider says they passed, give them a cookie
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if api_response.success == true then
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local user_key = sha.bin_to_hex(randbytes(16))
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local user_hash = utils.generate_secret(applet, captcha_cookie_secret, user_key, true)
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local signature = sha.hmac(sha.sha3_256, hmac_cookie_secret, user_key .. user_hash)
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local combined_cookie = user_key .. "#" .. user_hash .. "#" .. signature
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applet:add_header(
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"set-cookie",
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string.format(
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"z_ddos_captcha=%s; Expires=Thu, 31-Dec-37 23:55:55 GMT; Path=/; Domain=.%s; SameSite=Strict;%s",
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combined_cookie,
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applet.headers['host'][0],
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secure_cookie_flag
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)
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)
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valid_submission = valid_submission and true
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end
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end
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if not valid_submission then
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_M.kill_tor_circuit(applet)
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end
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-- redirect them to their desired page in applet.qs (query string)
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-- if they didn't get the appropriate cookies they will be sent back to the challenge page
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response_status_code = 302
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applet:add_header("location", applet.qs)
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-- else if its another http method, just 403 them
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else
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response_status_code = 403
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end
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-- finish sending the response
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applet:set_status(response_status_code)
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applet:add_header("content-type", "text/html; charset=utf-8")
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applet:add_header("content-length", string.len(response_body))
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applet:start_response()
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applet:send(response_body)
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end
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-- check if captcha is enabled, path+domain priority, then just domain, and 0 otherwise
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function _M.decide_checks_necessary(txn)
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local host = txn.sf:hdr("Host")
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local path = txn.sf:path();
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local captcha_map_lookup = captcha_map:lookup(host..path) or captcha_map:lookup(host) or 0
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captcha_map_lookup = tonumber(captcha_map_lookup)
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if captcha_map_lookup == 1 then
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txn:set_var("txn.validate_pow", true)
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elseif captcha_map_lookup == 2 then
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txn:set_var("txn.validate_captcha", true)
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txn:set_var("txn.validate_pow", true)
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end
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-- otherwise, domain+path was set to 0 (whitelist) or there is no entry in the map
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end
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-- check if captcha cookie is valid, separate secret from POW
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function _M.check_captcha_status(txn)
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local parsed_request_cookies = cookie.get_cookie_table(txn.sf:hdr("Cookie"))
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local received_captcha_cookie = parsed_request_cookies["z_ddos_captcha"] or ""
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-- split the cookie up
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local split_cookie = utils.split(received_captcha_cookie, "#")
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if #split_cookie ~= 3 then
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return
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end
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local given_user_key = split_cookie[1]
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local given_user_hash = split_cookie[2]
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local given_signature = split_cookie[3]
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-- regenerate the user hash and compare it
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local generated_user_hash = utils.generate_secret(txn, captcha_cookie_secret, given_user_key, false)
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if generated_user_hash ~= given_user_hash then
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return
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end
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-- regenerate the signature and compare it
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local generated_signature = sha.hmac(sha.sha3_256, hmac_cookie_secret, given_user_key .. given_user_hash)
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if given_signature == generated_signature then
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return txn:set_var("txn.captcha_passed", true)
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end
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end
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-- check if pow cookie is valid
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function _M.check_pow_status(txn)
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local parsed_request_cookies = cookie.get_cookie_table(txn.sf:hdr("Cookie"))
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local received_pow_cookie = parsed_request_cookies["z_ddos_pow"] or ""
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-- split the cookie up
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local split_cookie = utils.split(received_pow_cookie, "#")
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if #split_cookie ~= 4 then
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return
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end
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local given_user_key = split_cookie[1]
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local given_challenge_hash = split_cookie[2]
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local given_answer = split_cookie[3]
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local given_signature = split_cookie[4]
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-- regenerate the challenge and compare it
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local generated_challenge_hash = utils.generate_secret(txn, pow_cookie_secret, given_user_key, false)
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if given_challenge_hash ~= generated_challenge_hash then
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return
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end
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-- regenerate the signature and compare it
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local generated_signature = sha.hmac(sha.sha3_256, hmac_cookie_secret, given_user_key .. given_challenge_hash .. given_answer)
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if given_signature == generated_signature then
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return txn:set_var("txn.pow_passed", true)
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end
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end
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return _M
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