wekan/models/attachments.js

Attachments = new FS.Collection('attachments', {
  stores: [

    // XXX Add a new store for cover thumbnails so we don't load big images in
    // the general board view
    new FS.Store.GridFS('attachments'),
  ],
});

if (Meteor.isServer) {
  Attachments.allow({
    insert(userId, doc) {
      return allowIsBoardMember(userId, Boards.findOne(doc.boardId));
    },
    update(userId, doc) {
      return allowIsBoardMember(userId, Boards.findOne(doc.boardId));
    },
    remove(userId, doc) {
      return allowIsBoardMember(userId, Boards.findOne(doc.boardId));
    },
    // We authorize the attachment download either:
    // - if the board is public, everyone (even unconnected) can download it
    // - if the board is private, only board members can download it
    download(userId, doc) {
      const board = Boards.findOne(doc.boardId);
      if (board.isPublic()) {
        return true;
      } else {
        return board.hasMember(userId);
      }
    },

    fetch: ['boardId'],
  });
}

// XXX Enforce a schema for the Attachments CollectionFS

Attachments.files.before.insert((userId, doc) => {
  const file = new FS.File(doc);
  doc.userId = userId;

  // If the uploaded document is not an image we need to enforce browser
  // download instead of execution. This is particularly important for HTML
  // files that the browser will just execute if we don't serve them with the
  // appropriate `application/octet-stream` MIME header which can lead to user
  // data leaks. I imagine other formats (like PDF) can also be attack vectors.
  // See https://github.com/wekan/wekan/issues/99
  // XXX Should we use `beforeWrite` option of CollectionFS instead of
  // collection-hooks?
  if (!file.isImage()) {
    file.original.type = 'application/octet-stream';
  }
});

if (Meteor.isServer) {
  Attachments.files.after.insert((userId, doc) => {
    Activities.insert({
      userId,
      type: 'card',
      activityType: 'addAttachment',
      attachmentId: doc._id,
      boardId: doc.boardId,
      cardId: doc.cardId,
    });
  });

  Attachments.files.after.remove((userId, doc) => {
    Activities.remove({
      attachmentId: doc._id,
    });
  });
}