Fix XMPP stream not getting closed properly

The XMPP server may not flag the bind feature as required but we're
still required to bind resource to the stream in order to be able to
send IQ stanzas to other clients.

build/build.ts

@@ -51,6 +51,8 @@ const externals = [
   "tls",
   "http",
   "https",
+  "net",
+  "events",
   "zlib",
   "crypto",
   "util",

lib/api-functions.ts

@@ -29,10 +29,14 @@ import {
 import {
   httpConnectionRequest,
   udpConnectionRequest,
+  xmppConnectionRequest,
 } from "./connection-request";
 import { Expression, Task } from "./types";
 import { flattenDevice } from "./mongodb-functions";
 import { evaluate } from "./common/expression";
+import * as config from "../lib/config";
+
+const XMPP_CONFIGURED = !!config.get("XMPP_JID");
 
 export async function connectionRequest(
   deviceId: string,
@@ -44,7 +48,12 @@ export async function connectionRequest(
     device = flattenDevice(res);
   }
 
-  let connectionRequestUrl, udpConnectionRequestAddress, username, password;
+  let connectionRequestUrl,
+    udpConnectionRequestAddress,
+    stunEnable,
+    connReqJabberId,
+    username,
+    password;
 
   if (device["InternetGatewayDevice.ManagementServer.ConnectionRequestURL"]) {
     connectionRequestUrl = (device[
@@ -55,6 +64,12 @@ export async function connectionRequest(
         "InternetGatewayDevice.ManagementServer.UDPConnectionRequestAddress"
       ] || {}
     ).value || [""])[0];
+    stunEnable = ((
+      device["InternetGatewayDevice.ManagementServer.STUNEnable"] || {}
+    ).value || [""])[0];
+    connReqJabberId = ((
+      device["InternetGatewayDevice.ManagementServer.ConnReqJabberID"] || {}
+    ).value || [""])[0];
     username = ((
       device[
         "InternetGatewayDevice.ManagementServer.ConnectionRequestUsername"
@@ -72,6 +87,10 @@ export async function connectionRequest(
     udpConnectionRequestAddress = ((
       device["Device.ManagementServer.UDPConnectionRequestAddress"] || {}
     ).value || [""])[0];
+    stunEnable = ((device["Device.ManagementServer.STUNEnable"] || {})
+      .value || [""])[0];
+    connReqJabberId = ((device["Device.ManagementServer.ConnReqJabberID"] || {})
+      .value || [""])[0];
     username = ((
       device["Device.ManagementServer.ConnectionRequestUsername"] || {}
     ).value || [""])[0];
@@ -146,7 +165,7 @@ export async function connectionRequest(
   const debug = !!getConfig(snapshot, "cwmp.debug", {}, now, evalCallback);
 
   let udpProm;
-  if (udpConnectionRequestAddress) {
+  if (udpConnectionRequestAddress && +stunEnable) {
     udpProm = udpConnectionRequest(
       udpConnectionRequestAddress,
       authExp,
@@ -156,18 +175,30 @@ export async function connectionRequest(
     );
   }
 
-  const status = await httpConnectionRequest(
-    connectionRequestUrl,
-    authExp,
-    CONNECTION_REQUEST_ALLOW_BASIC_AUTH,
-    CONNECTION_REQUEST_TIMEOUT,
-    debug,
-    deviceId
-  );
+  let status;
 
-  if (udpProm) {
-    await udpProm;
-    return "";
+  if (connReqJabberId && XMPP_CONFIGURED) {
+    status = await xmppConnectionRequest(
+      connReqJabberId,
+      authExp,
+      CONNECTION_REQUEST_TIMEOUT,
+      debug,
+      deviceId
+    );
+  } else {
+    status = await httpConnectionRequest(
+      connectionRequestUrl,
+      authExp,
+      CONNECTION_REQUEST_ALLOW_BASIC_AUTH,
+      CONNECTION_REQUEST_TIMEOUT,
+      debug,
+      deviceId
+    );
+
+    if (udpProm) {
+      await udpProm;
+      return "";
+    }
   }
 
   return status;

lib/config.ts

@@ -101,6 +101,9 @@ const options = {
 
   // Should probably never be changed
   DEVICE_ONLINE_THRESHOLD: { type: "int", default: 4000 },
+
+  XMPP_JID: { type: "string", default: "" },
+  XMPP_PASSWORD: { type: "string", default: "" },
 };
 
 const allConfig: { [name: string]: string | number } = {};

lib/connection-request.ts

@@ -26,6 +26,10 @@ import { Expression } from "./types";
 import * as auth from "./auth";
 import * as extensions from "./extensions";
 import * as debug from "./debug";
+import XmppClient from "./xmpp-client";
+import * as config from "../lib/config";
+import { encodeEntities, parseAttrs, Element } from "./xml-parser";
+import * as logger from "../lib/logger";
 
 async function extractAuth(
   exp: Expression,
@@ -234,3 +238,84 @@ export async function udpConnectionRequest(
   }
   client.close();
 }
+
+const XMPP_JID = config.get("XMPP_JID") as string;
+const XMPP_PASSWORD = config.get("XMPP_PASSWORD") as string;
+const XMPP_RESOURCE = crypto.randomBytes(8).toString("hex");
+
+let xmppClient: XmppClient;
+
+function xmppClientOnError(err: Error): void {
+  xmppClient = null;
+  logger.error({
+    message: "XMPP exception",
+    exception: err,
+    pid: process.pid,
+  });
+}
+
+function xmppClientOnClose(): void {
+  xmppClient = null;
+}
+
+export async function xmppConnectionRequest(
+  jid: string,
+  authExp: Expression,
+  timeout: number,
+  _debug: boolean,
+  deviceId: string
+): Promise<string> {
+  if (!xmppClient) {
+    const [host, username] = XMPP_JID.split("@").reverse();
+    xmppClient = await XmppClient.connect({
+      host,
+      username,
+      resource: XMPP_RESOURCE,
+      password: XMPP_PASSWORD,
+      timeout: 120000,
+    });
+    xmppClient.on("error", xmppClientOnError);
+    xmppClient.on("close", xmppClientOnClose);
+    xmppClient.unref();
+  }
+
+  let username: string;
+  let password: string;
+
+  [username, password, authExp] = await extractAuth(authExp, null);
+  while (username != null && password != null) {
+    const msg = `<connectionRequest xmlns="urn:broadband-forum-org:cwmp:xmppConnReq-1-0"><username>${encodeEntities(
+      username
+    )}</username><password>${encodeEntities(
+      password
+    )}</password></connectionRequest>`;
+    let res: Element, rawRes: string, rawReq: string;
+    try {
+      ({ res, rawRes, rawReq } = await xmppClient.sendIqStanza(
+        XMPP_JID,
+        jid,
+        "get",
+        msg,
+        timeout
+      ));
+    } catch (err) {
+      return err.message;
+    }
+    if (_debug) {
+      debug.outgoingXmppStanza(deviceId, rawReq);
+      debug.incomingXmppStanza(deviceId, rawRes);
+    }
+    const attrs = parseAttrs(res.attrs);
+    const type = attrs.find((a) => a.name === "type");
+    if (type && type.value === "result") return "";
+    const error = res.children.find((c) => c.name === "error");
+    if (!error || !error.children[0])
+      return "Unexpected XMPP connection request response";
+    if (error.children[0].name === "service-unavailable")
+      return "Device is offline";
+    if (error.children[0].name !== "not-authorized")
+      return "Unexpected XMPP connection request response";
+    [username, password, authExp] = await extractAuth(authExp, null);
+  }
+  return "Incorrect connection request credentials";
+}

lib/debug.ts

@@ -202,3 +202,37 @@ export function outgoingUdpMessage(
     appendFileSync(DEBUG_FILE, JSON.stringify(msg) + "\n");
   else throw new Error(`Unrecognized DEBUG_FORMAT option`);
 }
+
+export function outgoingXmppStanza(deviceId: string, body: string): void {
+  if (!DEBUG_FILE) return;
+  const now = new Date();
+  const msg = {
+    event: "outgoing XMPP stanza",
+    timestamp: now,
+    deviceId: deviceId,
+    body: body,
+  };
+
+  if (DEBUG_FORMAT === "yaml")
+    appendFileSync(DEBUG_FILE, "---\n" + yaml.stringify(msg));
+  else if (DEBUG_FORMAT === "json")
+    appendFileSync(DEBUG_FILE, JSON.stringify(msg) + "\n");
+  else throw new Error(`Unrecognized DEBUG_FORMAT option`);
+}
+
+export function incomingXmppStanza(deviceId: string, body: string): void {
+  if (!DEBUG_FILE) return;
+  const now = new Date();
+  const msg = {
+    event: "incoming XMPP stanza",
+    timestamp: now,
+    deviceId: deviceId,
+    body: body,
+  };
+
+  if (DEBUG_FORMAT === "yaml")
+    appendFileSync(DEBUG_FILE, "---\n" + yaml.stringify(msg));
+  else if (DEBUG_FORMAT === "json")
+    appendFileSync(DEBUG_FILE, JSON.stringify(msg) + "\n");
+  else throw new Error(`Unrecognized DEBUG_FORMAT option`);
+}

lib/xmpp-client.ts

@@ -0,0 +1,481 @@
+/**
+ * Copyright 2013-2020  GenieACS Inc.
+ *
+ * This file is part of GenieACS.
+ *
+ * GenieACS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * GenieACS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with GenieACS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import * as net from "net";
+import * as tls from "tls";
+import { EventEmitter } from "events";
+import { createHash, createHmac, randomBytes } from "crypto";
+import { parseXml, Element, parseAttrs } from "./xml-parser";
+
+function encodeBase64(str: string): string {
+  return Buffer.from(str).toString("base64");
+}
+
+function decodeBase64(str: string): string {
+  return Buffer.from(str, "base64").toString();
+}
+
+function detectStreamTag(data: string): number {
+  const i1 = data.indexOf("<stream:stream");
+  if (i1 < 0) throw new Error("Cannot detect opening stream tag");
+  const i2 = data.indexOf(">", i1);
+  if (i2 < 0) throw new Error("Cannot detect opening stream tag");
+  return i2 + 1;
+}
+
+function xmppStream<T>(
+  socket: net.Socket,
+  callback: Generator<void, T, Element>
+): Promise<T> {
+  return new Promise((resolve, reject) => {
+    const onError = (err: Error): void => {
+      socket.removeListener("error", onError);
+      reject(err);
+    };
+    socket.on("error", onError);
+
+    const onData = (chunk: Buffer): void => {
+      try {
+        const str = chunk.toString("utf8");
+        const xml = parseXml(str);
+        const { value, done } = callback.next(xml.children[0]);
+        if (done) {
+          socket.removeListener("error", onError);
+          socket.removeListener("data", onData);
+          resolve(value as T);
+        }
+      } catch (err) {
+        socket.removeListener("error", onError);
+        socket.removeListener("data", onData);
+        reject(err);
+      }
+    };
+
+    socket.once("data", (chunk: Buffer) => {
+      try {
+        const str = chunk.toString("utf8");
+        const i = detectStreamTag(str);
+        const streamTagStr = str.slice(0, i);
+        const xml = parseXml(streamTagStr + "</stream:stream>");
+        callback.next(xml.children[0]);
+        chunk = chunk.slice(Buffer.byteLength(streamTagStr));
+        if (chunk.length) onData(chunk);
+        socket.on("data", onData);
+      } catch (err) {
+        socket.removeListener("error", onError);
+        socket.removeListener("data", onData);
+        reject(err);
+      }
+    });
+
+    try {
+      callback.next();
+    } catch (err) {
+      socket.removeListener("error", onError);
+      socket.removeListener("data", onData);
+      reject(err);
+    }
+  });
+}
+
+const INT_1 = Buffer.from([0, 0, 0, 1]);
+const saltedPasswordCache = {
+  password: "",
+  iterationCount: 0,
+  saltBase64: "",
+  salted: Buffer.allocUnsafe(0),
+};
+
+function saltPassword(
+  password: string,
+  saltBase64: string,
+  iteractionCount: number
+): Buffer {
+  if (
+    password === saltedPasswordCache.password &&
+    saltBase64 === saltedPasswordCache.saltBase64 &&
+    iteractionCount === saltedPasswordCache.iterationCount
+  )
+    return saltedPasswordCache.salted;
+
+  const hi = createHmac("sha1", password)
+    .update(Buffer.concat([Buffer.from(saltBase64, "base64"), INT_1]))
+    .digest();
+  let hi2: Buffer = hi;
+  for (let i = 1; i < iteractionCount; ++i) {
+    hi2 = createHmac("sha1", password).update(hi2).digest();
+    for (const [j, b] of hi2.entries()) hi[j] ^= b;
+  }
+
+  saltedPasswordCache.saltBase64 = saltBase64;
+  saltedPasswordCache.password = password;
+  saltedPasswordCache.iterationCount = iteractionCount;
+  saltedPasswordCache.salted = hi;
+
+  return hi;
+}
+
+function* loginPlain(
+  socket: net.Socket,
+  username: string,
+  password: string
+): Generator<void, void, Element> {
+  socket.write(
+    `<auth xmlns="urn:ietf:params:xml:ns:xmpp-sasl" mechanism="PLAIN">${encodeBase64(
+      `\x00${username}\x00${password}`
+    )}</auth>`
+  );
+  const res1 = yield;
+
+  if (
+    res1.name === "failure" &&
+    res1.children.some((c) => c.name === "not-authorized")
+  )
+    throw new Error("Not authorized");
+
+  if (res1.name !== "success")
+    throw new Error(`Unexpected response ${res1.name}`);
+}
+
+function* loginScram(
+  socket: net.Socket,
+  username: string,
+  password: string
+): Generator<void, void, Element> {
+  const cnonce = randomBytes(8).toString("base64");
+  const gs2Header = "n,,";
+  const clientFirstMessageBare = `n=${username},r=${cnonce}`;
+  const clientFirstMessage = gs2Header + clientFirstMessageBare;
+  socket.write(
+    `<auth xmlns="urn:ietf:params:xml:ns:xmpp-sasl" mechanism="SCRAM-SHA-1">${encodeBase64(
+      clientFirstMessage
+    )}</auth>`
+  );
+  const res1 = yield;
+  if (res1.name !== "challenge")
+    throw new Error(`Unexpected element ${res1.name}`);
+  const serverFirstMessage = decodeBase64(res1.text);
+
+  let iterationCount: number;
+  let saltBase64: string;
+  let nonce: string;
+  for (const s of serverFirstMessage.split(",")) {
+    if (s.startsWith("i=")) iterationCount = parseInt(s.slice(2));
+    else if (s.startsWith("s=")) saltBase64 = s.slice(2);
+    else if (s.startsWith("r=")) nonce = s.slice(2);
+  }
+  if (iterationCount == null || isNaN(iterationCount))
+    throw new Error("Invalid iteration count");
+  if (saltBase64 == null) throw new Error("Missing salt");
+  if (nonce == null) throw new Error("Missing nonce");
+
+  const saltedPassword = saltPassword(password, saltBase64, iterationCount);
+  const clientKey = createHmac("sha1", saltedPassword)
+    .update("Client Key")
+    .digest();
+  const storedKey = createHash("sha1").update(clientKey).digest();
+
+  const clientFinalMessageWithoutProof = `c=${encodeBase64(
+    gs2Header
+  )},r=${nonce}`;
+  const authMessage = `${clientFirstMessageBare},${serverFirstMessage},${clientFinalMessageWithoutProof}`;
+  const clientSignature = createHmac("sha1", storedKey)
+    .update(authMessage)
+    .digest();
+
+  const clientProof = Buffer.from(clientKey);
+  for (const [i, b] of clientSignature.entries()) clientProof[i] ^= b;
+
+  const clientFinalMessage = `${clientFinalMessageWithoutProof},p=${clientProof.toString(
+    "base64"
+  )}`;
+  socket.write(
+    `<response xmlns="urn:ietf:params:xml:ns:xmpp-sasl">${encodeBase64(
+      clientFinalMessage
+    )}</response>`
+  );
+  const res2 = yield;
+
+  if (
+    res2.name === "failure" &&
+    res2.children.some((c) => c.name === "not-authorized")
+  )
+    throw new Error("Not authorized");
+
+  if (res2.name !== "success")
+    throw new Error(`Unexpected response ${res2.name}`);
+
+  const serverKey = createHmac("sha1", saltedPassword)
+    .update("Server Key")
+    .digest();
+  const serverSignature = createHmac("sha1", serverKey)
+    .update(authMessage)
+    .digest("base64");
+
+  if (!decodeBase64(res2.text).endsWith(serverSignature))
+    throw new Error("Invalid server signature");
+}
+
+function* starttls(socket: net.Socket): Generator<void, void, Element> {
+  socket.write("<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
+  const res1 = yield;
+  if (res1.name !== "proceed") throw new Error("Failed to initiate STARTTLS");
+}
+
+function* bind(
+  socket: net.Socket,
+  resource: string
+): Generator<void, void, Element> {
+  const id = randomBytes(8).toString("base64");
+  socket.write(
+    `<iq id='${id}' type='set'><bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><resource>${resource}</resource></bind></iq>`
+  );
+  const res1 = yield;
+  if (res1.name !== "iq") throw new Error(`Unexpected element ${res1.name}`);
+  const attrs1 = parseAttrs(res1.attrs);
+  const idAttr = attrs1.find((a) => a.name === "id");
+  if (!idAttr || idAttr.value !== id) throw new Error("Invalid ID");
+  const typeAttr = attrs1.find((a) => a.name === "type");
+  if (!typeAttr) throw new Error("Missing type attribute");
+  if (typeAttr.value !== "result") throw new Error("Cannot bind to resource");
+}
+
+const STATUS_RESTART_STREAM = 1;
+const STATUS_STARTTLS = 2;
+
+function* init(
+  socket: net.Socket,
+  host: string,
+  username: string,
+  password: string,
+  resource: string
+): Generator<void, number, Element> {
+  socket.write(
+    `<?xml version='1.0'?><stream:stream from='${username}@${host}' to='${host}' version='1.0' xml:lang='en' xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams'>`
+  );
+  const open = yield;
+  if (open.name !== "stream:stream")
+    throw new Error(`Unexpected element ${open.name}`);
+  const features = yield;
+  if (features.name !== "stream:features")
+    throw new Error(`Unexpected element ${features.name}`);
+  for (const feature of features.children) {
+    if (feature.name === "starttls") {
+      if (feature.children.some((c) => c.name === "required")) {
+        yield* starttls(socket);
+        return STATUS_STARTTLS;
+      }
+    } else if (feature.name === "mechanisms") {
+      const mechanisms: Set<string> = new Set(
+        feature.children.map((c) => c.text)
+      );
+      if (mechanisms.has("PLAIN")) {
+        yield* loginPlain(socket, username, password);
+        return STATUS_RESTART_STREAM;
+      } else if (mechanisms.has("SCRAM-SHA-1")) {
+        yield* loginScram(socket, username, password);
+        return STATUS_RESTART_STREAM;
+      } else {
+        throw new Error("No supported SASL method");
+      }
+    } else if (feature.name === "bind") {
+      yield* bind(socket, resource);
+      return 0;
+    }
+  }
+  return 0;
+}
+
+function upgradeTls(socket: net.Socket, host: string): Promise<tls.TLSSocket> {
+  return new Promise((resolve, reject) => {
+    socket.on("error", reject);
+    const newSocket = tls.connect({ socket, host }, () => {
+      socket.removeListener("error", reject);
+      resolve(newSocket);
+    });
+  });
+}
+
+interface XmppClientOptions {
+  host: string;
+  port?: number;
+  username?: string;
+  password?: string;
+  resource?: string;
+  timeout?: number;
+}
+
+export default class XmppClient extends EventEmitter {
+  private _socket: net.Socket;
+  private _host: string;
+  private _username: string;
+  private _resource: string;
+  private _iqStanzaCallbacks: Map<
+    string,
+    (err: Error, r?: { rawRes: string; res: Element }) => void
+  >;
+
+  private constructor() {
+    super();
+    this._socket = null;
+    this._host = null;
+    this._username = null;
+    this._resource = null;
+    this._iqStanzaCallbacks = new Map();
+  }
+
+  static connect(opts: XmppClientOptions): Promise<XmppClient> {
+    return new Promise((resolve, reject) => {
+      let socket = new net.Socket();
+      socket.on("error", reject);
+
+      socket.connect(opts.port || 5222, opts.host, async () => {
+        socket.removeListener("error", reject);
+        try {
+          let status = 1;
+          while (status) {
+            if (status === STATUS_STARTTLS)
+              socket = await upgradeTls(socket, opts.host);
+            status = await xmppStream(
+              socket,
+              init(
+                socket,
+                opts.host,
+                opts.username,
+                opts.password,
+                opts.resource
+              )
+            );
+          }
+
+          const client = new XmppClient();
+          client._socket = socket;
+          client._host = opts.host;
+          client._username = opts.username;
+          client._resource = opts.resource;
+          socket.on("data", client._onData.bind(client));
+          socket.on("error", client._onError.bind(client));
+          if (opts.timeout)
+            socket.setTimeout(opts.timeout, client.close.bind(client));
+          resolve(client);
+        } catch (err) {
+          socket.destroy();
+          reject(err);
+        }
+      });
+    });
+  }
+
+  close(): void {
+    this._socket.end("</stream:stream>");
+    this._socket.removeAllListeners("data");
+    this._socket.removeAllListeners("error");
+    this.emit("close");
+  }
+
+  ref(): void {
+    this._socket.ref();
+  }
+
+  unref(): void {
+    this._socket.unref();
+  }
+
+  get host(): string {
+    return this._host;
+  }
+
+  get username(): string {
+    return this._username;
+  }
+
+  get resource(): string {
+    return this._resource;
+  }
+
+  private _onData(chunk: Buffer): void {
+    try {
+      let close = false;
+      let str = chunk.toString("utf8");
+      if (str.endsWith("</stream:stream>")) {
+        str = str.slice(0, -16);
+        close = true;
+      }
+      const xml = parseXml(str);
+      const idx = xml.children.map((c) => c.bodyIndex);
+      for (const [i, c] of xml.children.entries()) {
+        const s = str.slice(idx[i], idx[i + 1]);
+        if (c.name === "iq") {
+          const attrs = parseAttrs(c.attrs);
+          const id = attrs.find((a) => a.name === "id");
+          if (id) {
+            const cb = this._iqStanzaCallbacks.get(id.value);
+            if (cb) cb(null, { rawRes: s, res: c });
+          }
+        }
+        this.emit("stanza", c, s);
+      }
+      if (close) {
+        this._socket.removeAllListeners("data");
+        this._socket.removeAllListeners("error");
+        this.emit("close");
+      }
+    } catch (err) {
+      this._socket.removeAllListeners("data");
+      this._socket.removeAllListeners("error");
+      this.emit("error", err);
+    }
+  }
+
+  private _onError(err: Error): void {
+    this._socket.end();
+    this.emit("error", err);
+    for (const cb of this._iqStanzaCallbacks.values()) cb(err);
+  }
+
+  send(msg: string): void {
+    this._socket.write(msg);
+  }
+
+  sendIqStanza(
+    from: string,
+    to: string,
+    type: string,
+    body: string,
+    timeout = 3000
+  ): Promise<{ rawReq: string; rawRes: string; res: Element }> {
+    return new Promise((resolve, reject) => {
+      const id = randomBytes(8).toString("base64");
+      const rawReq = `<iq from="${from}" to="${to}" id="${id}" type="${type}">${body}</iq>`;
+      this.send(rawReq);
+      const t = setTimeout(() => {
+        this._iqStanzaCallbacks.delete(id);
+        reject(
+          new Error("Did not receive IQ stanza response in a timely manner")
+        );
+      }, timeout);
+      this._iqStanzaCallbacks.set(id, (err, r) => {
+        this._iqStanzaCallbacks.delete(id);
+        clearTimeout(t);
+        if (err) reject(err);
+        else resolve(Object.assign(r, { rawReq }));
+      });
+    });
+  }
+}