Paddy
3c4f3331d8
Jenkins Production Deployment
Reviewed-on: #8 Co-authored-by: Patrick Mueller <patrick@mueller-patrick.tech> Co-committed-by: Patrick Mueller <patrick@mueller-patrick.tech>
69 lines
2.5 KiB
TypeScript
69 lines
2.5 KiB
TypeScript
import * as crypto from 'crypto';
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import * as dotenv from 'dotenv';
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dotenv.config();
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const RATE_LIMIT_WINDOW_MIN = parseInt(process.env.TICKETS_RATE_LIMIT_WINDOW_MIN || '10', 10);
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const RATE_LIMIT_WINDOW_MS = RATE_LIMIT_WINDOW_MIN * 60 * 1000;
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// Salted per-process (not persisted/configured) - these limiters are
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// in-memory-only with no DB backstop, so the salt only needs to survive
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// for the current process's lifetime, unlike Feedback's FEEDBACK_IP_SALT
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// which also salts a persisted ip_hash column.
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const IP_SALT = crypto.randomBytes(32).toString('hex');
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export const hashIp = (ip: string): string => {
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return crypto.createHash('sha256').update(IP_SALT + ip).digest('hex');
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};
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/**
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* Two independent budgets, not one shared counter: validating a code (GET)
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* is a cheap, repeatable lookup a guest's own browser triggers on every
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* page load/reload/back-navigation of their redemption link - a shared
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* budget with redeem meant a guest could exhaust it just by reloading the
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* page a few times before ever submitting. Redeeming (POST) is the
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* sensitive, code-consuming action and stays tightly limited; validating
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* is limited too (it's still the enumeration vector for guessing codes),
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* just with a much larger allowance headroomed for normal page-reload
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* behaviour.
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*/
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const createLimiter = (max: number) => {
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const recentRequests = new Map<string, number[]>();
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const pruneOld = (timestamps: number[], now: number): number[] => {
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return timestamps.filter(t => now - t < RATE_LIMIT_WINDOW_MS);
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};
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const sweepInterval = setInterval(() => {
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const now = Date.now();
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for (const [ipHash, timestamps] of recentRequests) {
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if (pruneOld(timestamps, now).length === 0) {
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recentRequests.delete(ipHash);
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}
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}
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}, RATE_LIMIT_WINDOW_MS);
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sweepInterval.unref();
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return {
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isRateLimited: (ipHash: string): boolean => {
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const now = Date.now();
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const timestamps = pruneOld(recentRequests.get(ipHash) || [], now);
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if (timestamps.length > 0) {
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recentRequests.set(ipHash, timestamps);
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} else {
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recentRequests.delete(ipHash);
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}
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return timestamps.length >= max;
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},
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recordRequest: (ipHash: string): void => {
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const now = Date.now();
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const timestamps = pruneOld(recentRequests.get(ipHash) || [], now);
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timestamps.push(now);
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recentRequests.set(ipHash, timestamps);
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}
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};
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};
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export const validateLimiter = createLimiter(parseInt(process.env.TICKETS_VALIDATE_RATE_LIMIT_MAX || '30', 10));
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export const redeemLimiter = createLimiter(parseInt(process.env.TICKETS_REDEEM_RATE_LIMIT_MAX || '10', 10));
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