119 lines
3.6 KiB
JavaScript
119 lines
3.6 KiB
JavaScript
'use strict';
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/**
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* IMAP ID 注入代理（专治 163 "Unsafe Login"）
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*
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* 背景：LibreDesk 的 go-imap 客户端不发 IMAP ID 命令，163 会在 SELECT 时返回
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* "NO SELECT Unsafe Login"，导致邮箱无法收取。
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*
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* 本代理：明文监听 1993，TLS 连接上游 imap.163.com:993；
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* 在客户端发 SELECT/EXAMINE 之前，自动发送一条 ID 命令并吞掉它的响应。
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* 仅用于本地/内网 POC，不要在公网暴露。
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*/
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const net = require('net');
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const tls = require('tls');
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const LISTEN_PORT = Number(process.env.LISTEN_PORT || 1993);
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const UPSTREAM_HOST = process.env.UPSTREAM_HOST || 'imap.163.com';
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const UPSTREAM_PORT = Number(process.env.UPSTREAM_PORT || 993);
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const ID_LINE = process.env.ID_LINE || '("name" "libredesk" "version" "2.9" "vendor" "libredesk")';
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let connSeq = 0;
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function log(...args) {
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console.log(new Date().toISOString(), '[imap-id-proxy]', ...args);
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}
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function pipeLineSplitter(onLine) {
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let buf = '';
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return {
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push(chunk) {
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buf += chunk.toString('latin1');
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let idx;
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while ((idx = buf.indexOf('\r\n')) >= 0) {
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const line = buf.slice(0, idx);
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buf = buf.slice(idx + 2);
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onLine(line);
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}
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},
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};
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}
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const server = net.createServer((client) => {
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const id = ++connSeq;
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const tag = `P${id}`;
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let injected = false;
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let waitingId = false;
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const pendingFromClient = [];
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let upstreamWrite = null;
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log(`conn ${id} opened`);
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const upstream = tls.connect({ host: UPSTREAM_HOST, port: UPSTREAM_PORT, servername: UPSTREAM_HOST }, () => {
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log(`conn ${id} upstream TLS ready`);
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});
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upstream.setEncoding('latin1');
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client.setEncoding('latin1');
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upstreamWrite = (line) => upstream.write(`${line}\r\n`);
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const clientLines = pipeLineSplitter((line) => {
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const upper = line.toUpperCase();
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const isMailboxCmd = /^\S+\s+(SELECT|EXAMINE)\b/.test(upper);
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if (!injected && isMailboxCmd) {
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injected = true;
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waitingId = true;
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pendingFromClient.push(line);
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log(`conn ${id} injecting ID before: ${line.slice(0, 40)}`);
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upstream.write(`${tag} ID ${ID_LINE}\r\n`);
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return;
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}
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if (waitingId) {
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pendingFromClient.push(line);
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return;
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}
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upstream.write(`${line}\r\n`);
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});
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const upstreamLines = pipeLineSplitter((line) => {
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if (waitingId) {
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if (line.startsWith('* ID ')) return; // 吞掉 untagged ID 响应
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if (/^P\d+\s+(OK|NO|BAD)\b/i.test(line)) {
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const ok = /^P\d+\s+OK\b/i.test(line);
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log(`conn ${id} ID response: ${line.slice(0, 60)}`);
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waitingId = false;
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if (!ok) {
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// ID 被拒也继续转发，让上层自己报错
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client.write(`${line}\r\n`);
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}
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while (pendingFromClient.length) upstream.write(`${pendingFromClient.shift()}\r\n`);
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return;
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}
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// 其它服务器响应（如 * OK）先转发
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client.write(`${line}\r\n`);
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return;
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}
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client.write(`${line}\r\n`);
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});
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client.on('data', (chunk) => clientLines.push(chunk));
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upstream.on('data', (chunk) => upstreamLines.push(chunk));
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const close = (why) => {
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log(`conn ${id} closed (${why})`);
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client.destroy();
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upstream.destroy();
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};
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client.on('error', (e) => close(`client error ${e.message}`));
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upstream.on('error', (e) => {
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log(`conn ${id} upstream error ${e.message}`);
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client.destroy();
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});
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client.on('close', () => upstream.destroy());
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upstream.on('close', () => client.destroy());
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});
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server.listen(LISTEN_PORT, '0.0.0.0', () => {
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log(`listening :${LISTEN_PORT} -> ${UPSTREAM_HOST}:${UPSTREAM_PORT} (TLS)`);
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});
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