matrix-js-sdk/lib/crypto/algorithms/olm.js

Matrix Client-Server SDK for Javascript

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _defineProperty2 = _interopRequireDefault(require("@babel/runtime/helpers/defineProperty"));

var _logger = require("../../logger");

var olmlib = _interopRequireWildcard(require("../olmlib"));

var _deviceinfo = require("../deviceinfo");

var _base = require("./base");

function _getRequireWildcardCache(nodeInterop) { if (typeof WeakMap !== "function") return null; var cacheBabelInterop = new WeakMap(); var cacheNodeInterop = new WeakMap(); return (_getRequireWildcardCache = function (nodeInterop) { return nodeInterop ? cacheNodeInterop : cacheBabelInterop; })(nodeInterop); }

function _interopRequireWildcard(obj, nodeInterop) { if (!nodeInterop && obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(nodeInterop); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (key !== "default" && Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }

/*
Copyright 2016 - 2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

/**
 * Defines m.olm encryption/decryption
 *
 * @module crypto/algorithms/olm
 */
const DeviceVerification = _deviceinfo.DeviceInfo.DeviceVerification;

/**
 * Olm encryption implementation
 *
 * @constructor
 * @extends {module:crypto/algorithms/EncryptionAlgorithm}
 *
 * @param {object} params parameters, as per
 *     {@link module:crypto/algorithms/EncryptionAlgorithm}
 */
class OlmEncryption extends _base.EncryptionAlgorithm {
  constructor(...args) {
    super(...args);
    (0, _defineProperty2.default)(this, "sessionPrepared", false);
    (0, _defineProperty2.default)(this, "prepPromise", null);
  }

  /**
   * @private
    * @param {string[]} roomMembers list of currently-joined users in the room
   * @return {Promise} Promise which resolves when setup is complete
   */
  ensureSession(roomMembers) {
    if (this.prepPromise) {
      // prep already in progress
      return this.prepPromise;
    }

    if (this.sessionPrepared) {
      // prep already done
      return Promise.resolve();
    }

    this.prepPromise = this.crypto.downloadKeys(roomMembers).then(res => {
      return this.crypto.ensureOlmSessionsForUsers(roomMembers);
    }).then(() => {
      this.sessionPrepared = true;
    }).finally(() => {
      this.prepPromise = null;
    });
    return this.prepPromise;
  }
  /**
   * @inheritdoc
   *
   * @param {module:models/room} room
   * @param {string} eventType
   * @param {object} content plaintext event content
   *
   * @return {Promise} Promise which resolves to the new event body
   */


  async encryptMessage(room, eventType, content) {
    // pick the list of recipients based on the membership list.
    //
    // TODO: there is a race condition here! What if a new user turns up
    // just as you are sending a secret message?
    const members = await room.getEncryptionTargetMembers();
    const users = members.map(function (u) {
      return u.userId;
    });
    await this.ensureSession(users);
    const payloadFields = {
      room_id: room.roomId,
      type: eventType,
      content: content
    };
    const encryptedContent = {
      algorithm: olmlib.OLM_ALGORITHM,
      sender_key: this.olmDevice.deviceCurve25519Key,
      ciphertext: {}
    };
    const promises = [];

    for (let i = 0; i < users.length; ++i) {
      const userId = users[i];
      const devices = this.crypto.getStoredDevicesForUser(userId);

      for (let j = 0; j < devices.length; ++j) {
        const deviceInfo = devices[j];
        const key = deviceInfo.getIdentityKey();

        if (key == this.olmDevice.deviceCurve25519Key) {
          // don't bother sending to ourself
          continue;
        }

        if (deviceInfo.verified == DeviceVerification.BLOCKED) {
          // don't bother setting up sessions with blocked users
          continue;
        }

        promises.push(olmlib.encryptMessageForDevice(encryptedContent.ciphertext, this.userId, this.deviceId, this.olmDevice, userId, deviceInfo, payloadFields));
      }
    }

    return await Promise.all(promises).then(() => encryptedContent);
  }

}
/**
 * Olm decryption implementation
 *
 * @constructor
 * @extends {module:crypto/algorithms/DecryptionAlgorithm}
 * @param {object} params parameters, as per
 *     {@link module:crypto/algorithms/DecryptionAlgorithm}
 */


class OlmDecryption extends _base.DecryptionAlgorithm {
  /**
   * @inheritdoc
   *
   * @param {MatrixEvent} event
   *
   * returns a promise which resolves to a
   * {@link module:crypto~EventDecryptionResult} once we have finished
   * decrypting. Rejects with an `algorithms.DecryptionError` if there is a
   * problem decrypting the event.
   */
  async decryptEvent(event) {
    const content = event.getWireContent();
    const deviceKey = content.sender_key;
    const ciphertext = content.ciphertext;

    if (!ciphertext) {
      throw new _base.DecryptionError("OLM_MISSING_CIPHERTEXT", "Missing ciphertext");
    }

    if (!(this.olmDevice.deviceCurve25519Key in ciphertext)) {
      throw new _base.DecryptionError("OLM_NOT_INCLUDED_IN_RECIPIENTS", "Not included in recipients");
    }

    const message = ciphertext[this.olmDevice.deviceCurve25519Key];
    let payloadString;

    try {
      payloadString = await this.decryptMessage(deviceKey, message);
    } catch (e) {
      throw new _base.DecryptionError("OLM_BAD_ENCRYPTED_MESSAGE", "Bad Encrypted Message", {
        sender: deviceKey,
        err: e
      });
    }

    const payload = JSON.parse(payloadString); // check that we were the intended recipient, to avoid unknown-key attack
    // https://github.com/vector-im/vector-web/issues/2483

    if (payload.recipient != this.userId) {
      throw new _base.DecryptionError("OLM_BAD_RECIPIENT", "Message was intented for " + payload.recipient);
    }

    if (payload.recipient_keys.ed25519 != this.olmDevice.deviceEd25519Key) {
      throw new _base.DecryptionError("OLM_BAD_RECIPIENT_KEY", "Message not intended for this device", {
        intended: payload.recipient_keys.ed25519,
        our_key: this.olmDevice.deviceEd25519Key
      });
    } // check that the original sender matches what the homeserver told us, to
    // avoid people masquerading as others.
    // (this check is also provided via the sender's embedded ed25519 key,
    // which is checked elsewhere).


    if (payload.sender != event.getSender()) {
      throw new _base.DecryptionError("OLM_FORWARDED_MESSAGE", "Message forwarded from " + payload.sender, {
        reported_sender: event.getSender()
      });
    } // Olm events intended for a room have a room_id.


    if (payload.room_id !== event.getRoomId()) {
      throw new _base.DecryptionError("OLM_BAD_ROOM", "Message intended for room " + payload.room_id, {
        reported_room: event.getRoomId()
      });
    }

    const claimedKeys = payload.keys || {};
    return {
      clearEvent: payload,
      senderCurve25519Key: deviceKey,
      claimedEd25519Key: claimedKeys.ed25519 || null
    };
  }
  /**
   * Attempt to decrypt an Olm message
   *
   * @param {string} theirDeviceIdentityKey  Curve25519 identity key of the sender
   * @param {object} message  message object, with 'type' and 'body' fields
   *
   * @return {string} payload, if decrypted successfully.
   */


  async decryptMessage(theirDeviceIdentityKey, message) {
    // This is a wrapper that serialises decryptions of prekey messages, because
    // otherwise we race between deciding we have no active sessions for the message
    // and creating a new one, which we can only do once because it removes the OTK.
    if (message.type !== 0) {
      // not a prekey message: we can safely just try & decrypt it
      return this.reallyDecryptMessage(theirDeviceIdentityKey, message);
    } else {
      const myPromise = this.olmDevice.olmPrekeyPromise.then(() => {
        return this.reallyDecryptMessage(theirDeviceIdentityKey, message);
      }); // we want the error, but don't propagate it to the next decryption

      this.olmDevice.olmPrekeyPromise = myPromise.catch(() => {});
      return await myPromise;
    }
  }

  async reallyDecryptMessage(theirDeviceIdentityKey, message) {
    const sessionIds = await this.olmDevice.getSessionIdsForDevice(theirDeviceIdentityKey); // try each session in turn.

    const decryptionErrors = {};

    for (let i = 0; i < sessionIds.length; i++) {
      const sessionId = sessionIds[i];

      try {
        const payload = await this.olmDevice.decryptMessage(theirDeviceIdentityKey, sessionId, message.type, message.body);

        _logger.logger.log("Decrypted Olm message from " + theirDeviceIdentityKey + " with session " + sessionId);

        return payload;
      } catch (e) {
        const foundSession = await this.olmDevice.matchesSession(theirDeviceIdentityKey, sessionId, message.type, message.body);

        if (foundSession) {
          // decryption failed, but it was a prekey message matching this
          // session, so it should have worked.
          throw new Error("Error decrypting prekey message with existing session id " + sessionId + ": " + e.message);
        } // otherwise it's probably a message for another session; carry on, but
        // keep a record of the error


        decryptionErrors[sessionId] = e.message;
      }
    }

    if (message.type !== 0) {
      // not a prekey message, so it should have matched an existing session, but it
      // didn't work.
      if (sessionIds.length === 0) {
        throw new Error("No existing sessions");
      }

      throw new Error("Error decrypting non-prekey message with existing sessions: " + JSON.stringify(decryptionErrors));
    } // prekey message which doesn't match any existing sessions: make a new
    // session.


    let res;

    try {
      res = await this.olmDevice.createInboundSession(theirDeviceIdentityKey, message.type, message.body);
    } catch (e) {
      decryptionErrors["(new)"] = e.message;
      throw new Error("Error decrypting prekey message: " + JSON.stringify(decryptionErrors));
    }

    _logger.logger.log("created new inbound Olm session ID " + res.session_id + " with " + theirDeviceIdentityKey);

    return res.payload;
  }

}

(0, _base.registerAlgorithm)(olmlib.OLM_ALGORITHM, OlmEncryption, OlmDecryption);