d3e509517c
Closes #30 Introduces the "challenge" field in bot rule definitions: ```json { "name": "generic-bot-catchall", "user_agent_regex": "(?i:bot|crawler)", "action": "CHALLENGE", "challenge": { "difficulty": 16, "report_as": 4, "algorithm": "slow" } } ``` This makes Anubis return a challenge page for every user agent with "bot" or "crawler" in it (case-insensitively) with difficulty 16 using the old "slow" algorithm but reporting in the client as difficulty 4. This is useful when you want to make certain clients in particular suffer. Additional validation and testing logic has been added to make sure that users do not define "impossible" challenge settings. If no algorithm is specified, Anubis defaults to the "fast" algorithm. Signed-off-by: Xe Iaso <me@xeiaso.net>
93 lines
2.3 KiB
JavaScript
93 lines
2.3 KiB
JavaScript
export default function process(data, difficulty = 5, threads = (navigator.hardwareConcurrency || 1)) {
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console.debug("fast algo");
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return new Promise((resolve, reject) => {
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let webWorkerURL = URL.createObjectURL(new Blob([
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'(', processTask(), ')()'
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], { type: 'application/javascript' }));
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const workers = [];
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for (let i = 0; i < threads; i++) {
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let worker = new Worker(webWorkerURL);
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worker.onmessage = (event) => {
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workers.forEach(worker => worker.terminate());
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worker.terminate();
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resolve(event.data);
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};
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worker.onerror = (event) => {
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worker.terminate();
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reject();
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};
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worker.postMessage({
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data,
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difficulty,
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nonce: i,
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threads,
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});
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workers.push(worker);
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}
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URL.revokeObjectURL(webWorkerURL);
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});
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}
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function processTask() {
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return function () {
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const sha256 = (text) => {
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const encoded = new TextEncoder().encode(text);
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return crypto.subtle.digest("SHA-256", encoded.buffer);
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};
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function uint8ArrayToHexString(arr) {
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return Array.from(arr)
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.map((c) => c.toString(16).padStart(2, "0"))
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.join("");
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}
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addEventListener('message', async (event) => {
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let data = event.data.data;
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let difficulty = event.data.difficulty;
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let hash;
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let nonce = event.data.nonce;
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let threads = event.data.threads;
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while (true) {
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const currentHash = await sha256(data + nonce);
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const thisHash = new Uint8Array(currentHash);
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let valid = true;
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for (let j = 0; j < difficulty; j++) {
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const byteIndex = Math.floor(j / 2); // which byte we are looking at
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const nibbleIndex = j % 2; // which nibble in the byte we are looking at (0 is high, 1 is low)
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let nibble = (thisHash[byteIndex] >> (nibbleIndex === 0 ? 4 : 0)) & 0x0F; // Get the nibble
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if (nibble !== 0) {
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valid = false;
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break;
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}
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}
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if (valid) {
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hash = uint8ArrayToHexString(thisHash);
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console.log(hash);
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break;
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}
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nonce += threads;
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}
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postMessage({
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hash,
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data,
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difficulty,
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nonce,
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});
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});
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}.toString();
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}
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