mirror of
https://github.com/vector-im/hydrogen-web.git
synced 2024-12-25 12:35:01 +01:00
136 lines
4.4 KiB
JavaScript
136 lines
4.4 KiB
JavaScript
/*
|
|
Copyright 2020 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.
|
|
*/
|
|
|
|
|
|
// WARNING: We have to be very careful about what mime-types we allow into blobs.
|
|
//
|
|
// This means that the content is rendered using the origin of the script which
|
|
// called createObjectURL(), and so if the content contains any scripting then it
|
|
// will pose a XSS vulnerability when the browser renders it. This is particularly
|
|
// bad if the user right-clicks the URI and pastes it into a new window or tab,
|
|
// as the blob will then execute with access to Element's full JS environment(!)
|
|
//
|
|
// See https://github.com/matrix-org/matrix-react-sdk/pull/1820#issuecomment-385210647
|
|
// for details.
|
|
//
|
|
// We mitigate this by only allowing mime-types into blobs which we know don't
|
|
// contain any scripting, and instantiate all others as application/octet-stream
|
|
// regardless of what mime-type the event claimed. Even if the payload itself
|
|
// is some malicious HTML, the fact we instantiate it with a media mimetype or
|
|
// application/octet-stream means the browser doesn't try to render it as such.
|
|
//
|
|
// One interesting edge case is image/svg+xml, which empirically *is* rendered
|
|
// correctly if the blob is set to the src attribute of an img tag (for thumbnails)
|
|
// *even if the mimetype is application/octet-stream*. However, empirically JS
|
|
// in the SVG isn't executed in this scenario, so we seem to be okay.
|
|
//
|
|
// Tested on Chrome 65 and Firefox 60
|
|
//
|
|
// The list below is taken mainly from
|
|
// https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
|
|
// N.B. Matrix doesn't currently specify which mimetypes are valid in given
|
|
// events, so we pick the ones which HTML5 browsers should be able to display
|
|
//
|
|
// For the record, mime-types which must NEVER enter this list below include:
|
|
// text/html, text/xhtml, image/svg, image/svg+xml, image/pdf, and similar.
|
|
|
|
const ALLOWED_BLOB_MIMETYPES = {
|
|
'image/jpeg': true,
|
|
'image/gif': true,
|
|
'image/png': true,
|
|
|
|
'video/mp4': true,
|
|
'video/webm': true,
|
|
'video/ogg': true,
|
|
'video/quicktime': true,
|
|
'video/VP8': true,
|
|
|
|
'audio/mp4': true,
|
|
'audio/webm': true,
|
|
'audio/aac': true,
|
|
'audio/mpeg': true,
|
|
'audio/ogg': true,
|
|
'audio/wave': true,
|
|
'audio/wav': true,
|
|
'audio/x-wav': true,
|
|
'audio/x-pn-wav': true,
|
|
'audio/flac': true,
|
|
'audio/x-flac': true,
|
|
};
|
|
|
|
const DEFAULT_MIMETYPE = 'application/octet-stream';
|
|
|
|
export class BlobHandle {
|
|
constructor(blob, buffer = null) {
|
|
this._blob = blob;
|
|
this._buffer = buffer;
|
|
this._url = null;
|
|
}
|
|
|
|
static fromBuffer(buffer, mimetype) {
|
|
mimetype = mimetype ? mimetype.split(";")[0].trim() : '';
|
|
if (!ALLOWED_BLOB_MIMETYPES[mimetype]) {
|
|
mimetype = DEFAULT_MIMETYPE;
|
|
}
|
|
return new BlobHandle(new Blob([buffer], {type: mimetype}), buffer);
|
|
}
|
|
|
|
static fromBlob(blob) {
|
|
// ok to not filter mimetypes as these are local files
|
|
return new BlobHandle(blob);
|
|
}
|
|
|
|
get nativeBlob() {
|
|
return this._blob;
|
|
}
|
|
|
|
async readAsBuffer() {
|
|
if (this._buffer) {
|
|
return this._buffer;
|
|
} else {
|
|
const reader = new FileReader();
|
|
const promise = new Promise((resolve, reject) => {
|
|
reader.addEventListener("load", evt => resolve(evt.target.result));
|
|
reader.addEventListener("error", evt => reject(evt.target.error));
|
|
});
|
|
reader.readAsArrayBuffer(this._blob);
|
|
return promise;
|
|
}
|
|
}
|
|
|
|
get url() {
|
|
if (!this._url) {
|
|
this._url = URL.createObjectURL(this._blob);
|
|
}
|
|
return this._url;
|
|
}
|
|
|
|
get size() {
|
|
return this._blob.size;
|
|
}
|
|
|
|
get mimeType() {
|
|
return this._blob.type || DEFAULT_MIMETYPE;
|
|
}
|
|
|
|
dispose() {
|
|
if (this._url) {
|
|
URL.revokeObjectURL(this._url);
|
|
this._url = null;
|
|
}
|
|
}
|
|
}
|