112 lines
3.9 KiB
TypeScript
112 lines
3.9 KiB
TypeScript
/**
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* AES-256-GCM 加解密工具
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*
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* 用于保护数据库中存储的网盘 Cookie。
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* 加密密钥从环境变量 COOKIE_ENCRYPTION_KEY 读取，
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* 未设置时自动生成随机密钥（仅当前进程有效，重启后旧数据不可解密）。
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*
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* 生产环境必须设置 COOKIE_ENCRYPTION_KEY！
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*/
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import * as crypto from 'crypto';
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const ALGORITHM = 'aes-256-gcm';
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const IV_LENGTH = 12; // 96-bit nonce for GCM
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const TAG_LENGTH = 16; // 128-bit auth tag
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const KEY_LENGTH = 32; // 256-bit key
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let ENCRYPTION_KEY: Buffer | null = null;
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function getKey(): Buffer {
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if (ENCRYPTION_KEY) return ENCRYPTION_KEY;
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const envKey = process.env.COOKIE_ENCRYPTION_KEY;
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if (envKey && envKey.length >= 32) {
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// Use SHA-256 to derive a consistent 32-byte key from any length input
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ENCRYPTION_KEY = crypto.createHash('sha256').update(envKey).digest();
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console.log('[Crypto] Cookie encryption enabled (key from COOKIE_ENCRYPTION_KEY)');
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} else if (envKey) {
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// Short key: still use SHA-256
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ENCRYPTION_KEY = crypto.createHash('sha256').update(envKey).digest();
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console.log('[Crypto] Cookie encryption enabled (key from COOKIE_ENCRYPTION_KEY, SHA-256 derived)');
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} else {
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// Default stable key (not ephemeral) — data survives container restart
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ENCRYPTION_KEY = crypto.createHash('sha256').update('cloudsearch-cookie-key-v1').digest();
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console.log('[Crypto] Cookie encryption enabled (built-in default key — set COOKIE_ENCRYPTION_KEY in .env for extra security)');
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}
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return ENCRYPTION_KEY;
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}
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/**
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* Encrypt plaintext. Returns base64-encoded ciphertext (includes IV + auth tag).
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*/
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export function encrypt(plaintext: string): string {
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if (!plaintext) return '';
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const key = getKey();
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const iv = crypto.randomBytes(IV_LENGTH);
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const cipher = crypto.createCipheriv(ALGORITHM, key, iv);
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const encrypted = Buffer.concat([
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cipher.update(plaintext, 'utf8'),
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cipher.final(),
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]);
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const tag = cipher.getAuthTag();
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// Format: iv (12) + tag (16) + ciphertext
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const combined = Buffer.concat([iv, tag, encrypted]);
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return combined.toString('base64');
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}
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/**
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* Decrypt base64-encoded ciphertext. Returns original plaintext.
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* Returns empty string if decryption fails (corrupted data or wrong key).
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*/
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export function decrypt(encoded: string): string {
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if (!encoded) return '';
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try {
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const key = getKey();
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const combined = Buffer.from(encoded, 'base64');
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if (combined.length < IV_LENGTH + TAG_LENGTH + 1) {
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console.warn('[Crypto] Ciphertext too short, returning as-is (possibly unencrypted legacy data)');
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// Legacy data: stored as plaintext before encryption was added
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return encoded;
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}
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const iv = combined.subarray(0, IV_LENGTH);
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const tag = combined.subarray(IV_LENGTH, IV_LENGTH + TAG_LENGTH);
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const ciphertext = combined.subarray(IV_LENGTH + TAG_LENGTH);
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const decipher = crypto.createDecipheriv(ALGORITHM, key, iv);
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decipher.setAuthTag(tag);
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const decrypted = Buffer.concat([
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decipher.update(ciphertext),
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decipher.final(),
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]);
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return decrypted.toString('utf8');
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} catch (err: any) {
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// If it looks like base64 but decryption fails, it might be legacy plaintext
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// stored before encryption was enabled. Try returning as-is.
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if (err.message?.includes('unsupported state') || err.message?.includes('authentication')) {
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console.warn('[Crypto] Decryption failed (possibly legacy plaintext), returning as-is');
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return encoded;
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}
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console.error('[Crypto] Decryption error:', err.message);
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return '';
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}
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}
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/**
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* Check if a string appears to be encrypted (base64 with IV+tag prefix).
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* Used for migration: re-encrypt legacy plaintext cookies.
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*/
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export function isEncrypted(value: string): boolean {
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if (!value) return false;
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try {
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const combined = Buffer.from(value, 'base64');
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return combined.length > IV_LENGTH + TAG_LENGTH;
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} catch {
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return false;
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}
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}
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