bunkerized-nginx/lua/javascript.lua
2020-10-14 14:28:00 +02:00

57 lines
1.6 KiB
Lua

local M = {}
local session = require "resty.session"
function M.get_challenge ()
local charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIKLMNOPQRSTUVWXYZ0123456789"
math.randomseed(os.clock()*os.time())
local random = ""
local rand = 0
for i = 1, 20 do
rand = math.random(1, #charset)
random = random .. charset:sub(rand, rand)
end
return random
end
function M.get_code (challenge, antibot_uri, original_uri)
return string.format([[
<html>
<head>
</head>
<body>
<script>
async function digestMessage(message) {
const msgUint8 = new TextEncoder().encode(message);
const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8);
const hashArray = Array.from(new Uint8Array(hashBuffer));
const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
return hashHex;
}
(async () => {
const digestHex = await digestMessage('%s');
xhr = new XMLHttpRequest();
xhr.open('POST', '%s');
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.onload = function() {
if (xhr.status === 200) {
window.location.replace('%s');
}
};
xhr.send(encodeURI('challenge=' + digestHex));
})();
</script>
</body>
</html>
]], challenge, antibot_uri, original_uri)
end
function M.check (challenge, user)
local resty_sha256 = require "resty.sha256"
local str = require "resty.string"
local sha256 = resty_sha256:new()
sha256:update(challenge)
local digest = sha256:final()
return str.to_hex(digest) == user
end
return M