Fix e2e attachment download by using iframes. (#562)

* Render attachments inside iframes.

* Fix up the image and video views

* Fix m.audio

* Comments, and only use the cross domain renderer if the attachment is encrypted

* Fix whitespace

* Don't decrypt file attachments immediately

* Use https://usercontent.riot.im/v1.html by default

* typos

* Put the config in the React context.

Use it in MFileBody to configure the cross origin renderer URL.

* Call it appConfig in the context

* Return the promises so they don't get dropped
pull/21833/head
Mark Haines 2016-12-02 14:21:07 +00:00 committed by GitHub
parent 0a42a78b13
commit 81e429eb14
6 changed files with 253 additions and 85 deletions

View File

@ -66,10 +66,20 @@ module.exports = React.createClass({
defaultDeviceDisplayName: React.PropTypes.string,
},
childContextTypes: {
appConfig: React.PropTypes.object,
},
AuxPanel: {
RoomSettings: "room_settings",
},
getChildContext: function() {
return {
appConfig: this.props.config,
}
},
getInitialState: function() {
var s = {
loading: true,

View File

@ -21,7 +21,7 @@ import MFileBody from './MFileBody';
import MatrixClientPeg from '../../../MatrixClientPeg';
import sdk from '../../../index';
import { decryptFile } from '../../../utils/DecryptFile';
import { decryptFile, readBlobAsDataUri } from '../../../utils/DecryptFile';
export default class MAudioBody extends React.Component {
constructor(props) {
@ -29,6 +29,7 @@ export default class MAudioBody extends React.Component {
this.state = {
playing: false,
decryptedUrl: null,
decryptedBlob: null,
error: null,
}
}
@ -50,9 +51,14 @@ export default class MAudioBody extends React.Component {
componentDidMount() {
var content = this.props.mxEvent.getContent();
if (content.file !== undefined && this.state.decryptedUrl === null) {
decryptFile(content.file).done((url) => {
var decryptedBlob;
decryptFile(content.file).then(function(blob) {
decryptedBlob = blob;
return readBlobAsDataUri(decryptedBlob);
}).done((url) => {
this.setState({
decryptedUrl: url,
decryptedBlob: decryptedBlob,
});
}, (err) => {
console.warn("Unable to decrypt attachment: ", err);
@ -93,7 +99,7 @@ export default class MAudioBody extends React.Component {
return (
<span className="mx_MAudioBody">
<audio src={contentUrl} controls />
<MFileBody {...this.props} decryptedUrl={this.state.decryptedUrl} />
<MFileBody {...this.props} decryptedBlob={this.state.decryptedBlob} />
</span>
);
}

View File

@ -63,15 +63,137 @@ function updateTintedDownloadImage() {
Tinter.registerTintable(updateTintedDownloadImage);
// User supplied content can contain scripts, we have to be careful that
// we don't accidentally run those script within the same origin as the
// client. Otherwise those scripts written by remote users can read
// the access token and end-to-end keys that are in local storage.
//
// For attachments downloaded directly from the homeserver we can use
// Content-Security-Policy headers to disable script execution.
//
// But attachments with end-to-end encryption are more difficult to handle.
// We need to decrypt the attachment on the client and then display it.
// To display the attachment we need to turn the decrypted bytes into a URL.
//
// There are two ways to turn bytes into URLs, data URL and blob URLs.
// Data URLs aren't suitable for downloading a file because Chrome has a
// 2MB limit on the size of URLs that can be viewed in the browser or
// downloaded. This limit does not seem to apply when the url is used as
// the source attribute of an image tag.
//
// Blob URLs are generated using window.URL.createObjectURL and unforuntately
// for our purposes they inherit the origin of the page that created them.
// This means that any scripts that run when the URL is viewed will be able
// to access local storage.
//
// The easiest solution is to host the code that generates the blob URL on
// a different domain to the client.
// Another possibility is to generate the blob URL within a sandboxed iframe.
// The downside of using a second domain is that it complicates hosting,
// the downside of using a sandboxed iframe is that the browers are overly
// restrictive in what you are allowed to do with the generated URL.
//
// For now given how unusable the blobs generated in sandboxed iframes are we
// default to using a renderer hosted on "usercontent.riot.im". This is
// overridable so that people running their own version of the client can
// choose a different renderer.
//
// To that end the first version of the blob generation will be the following
// html:
//
// <html><head><script>
// window.onmessage=function(e){eval("("+e.data.code+")")(e)}
// </script></head><body></body></html>
//
// This waits to receive a message event sent using the window.postMessage API.
// When it receives the event it evals a javascript function in data.code and
// runs the function passing the event as an argument.
//
// In particular it means that the rendering function can be written as a
// ordinary javascript function which then is turned into a string using
// toString().
//
const DEFAULT_CROSS_ORIGIN_RENDERER = "https://usercontent.riot.im/v1.html";
/**
* Render the attachment inside the iframe.
* We can't use imported libraries here so this has to be vanilla JS.
*/
function remoteRender(event) {
const data = event.data;
const img = document.createElement("img");
img.id = "img";
img.src = data.imgSrc;
const a = document.createElement("a");
a.id = "a";
a.rel = data.rel;
a.target = data.target;
a.download = data.download;
a.style = data.style;
a.href = window.URL.createObjectURL(data.blob);
a.appendChild(img);
a.appendChild(document.createTextNode(data.textContent));
const body = document.body;
// Don't display scrollbars if the link takes more than one line
// to display.
body.style = "margin: 0px; overflow: hidden";
body.appendChild(a);
}
/**
* Update the tint inside the iframe.
* We can't use imported libraries here so this has to be vanilla JS.
*/
function remoteSetTint(event) {
const data = event.data;
const img = document.getElementById("img");
img.src = data.imgSrc;
img.style = data.imgStyle;
const a = document.getElementById("a");
a.style = data.style;
}
/**
* Get the current CSS style for a DOMElement.
* @param {HTMLElement} element The element to get the current style of.
* @return {string} The CSS style encoded as a string.
*/
function computedStyle(element) {
if (!element) {
return "";
}
const style = window.getComputedStyle(element, null);
var cssText = style.cssText;
if (cssText == "") {
// Firefox doesn't implement ".cssText" for computed styles.
// https://bugzilla.mozilla.org/show_bug.cgi?id=137687
for (var i = 0; i < style.length; i++) {
cssText += style[i] + ":";
cssText += style.getPropertyValue(style[i]) + ";";
}
}
return cssText;
}
module.exports = React.createClass({
displayName: 'MFileBody',
getInitialState: function() {
return {
decryptedUrl: (this.props.decryptedUrl ? this.props.decryptedUrl : null),
decryptedBlob: (this.props.decryptedBlob ? this.props.decryptedBlob : null),
};
},
contextTypes: {
appConfig: React.PropTypes.object,
},
/**
* Extracts a human readable label for the file attachment to use as
* link text.
@ -102,11 +224,7 @@ module.exports = React.createClass({
_getContentUrl: function() {
const content = this.props.mxEvent.getContent();
if (content.file !== undefined) {
return this.state.decryptedUrl;
} else {
return MatrixClientPeg.get().mxcUrlToHttp(content.url);
}
},
componentDidMount: function() {
@ -127,41 +245,52 @@ module.exports = React.createClass({
if (this.refs.downloadImage) {
this.refs.downloadImage.src = tintedDownloadImageURL;
}
if (this.refs.iframe) {
// If the attachment is encrypted then the download image
// will be inside the iframe so we wont be able to update
// it directly.
this.refs.iframe.contentWindow.postMessage({
code: remoteSetTint.toString(),
imgSrc: tintedDownloadImageURL,
style: computedStyle(this.refs.dummyLink),
}, "*");
}
},
render: function() {
const content = this.props.mxEvent.getContent();
const text = this.presentableTextForFile(content);
const isEncrypted = content.file !== undefined;
const fileName = content.body && content.body.length > 0 ? content.body : "Attachment";
const contentUrl = this._getContentUrl();
const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
if (content.file !== undefined && this.state.decryptedUrl === null) {
if (isEncrypted) {
if (this.state.decryptedBlob === null) {
// Need to decrypt the attachment
// Wait for the user to click on the link before downloading
// and decrypting the attachment.
var decrypting = false;
const decrypt = () => {
if (decrypting) {
return false;
}
decrypting = true;
decryptFile(content.file).then((url) => {
decryptFile(content.file).then((blob) => {
this.setState({
decryptedUrl: url,
decryptedBlob: blob,
});
}).catch((err) => {
console.warn("Unable to decrypt attachment: ", err)
// Set a placeholder image when we can't decrypt the image
Modal.createDialog(ErrorDialog, {
description: "Error decrypting attachment"
});
}).finally(function() {
}).finally(() => {
decrypting = false;
}).done();
return false;
return;
});
};
// Need to decrypt the attachment
// The attachment is decrypted in componentDidMount.
// For now add an img tag with a spinner.
return (
<span className="mx_MFileBody" ref="body">
<div className="mx_MImageBody_download">
@ -173,44 +302,51 @@ module.exports = React.createClass({
);
}
const contentUrl = this._getContentUrl();
// When the iframe loads we tell it to render a download link
const onIframeLoad = (ev) => {
ev.target.contentWindow.postMessage({
code: remoteRender.toString(),
imgSrc: tintedDownloadImageURL,
style: computedStyle(this.refs.dummyLink),
blob: this.state.decryptedBlob,
// Set a download attribute for encrypted files so that the file
// will have the correct name when the user tries to download it.
// We can't provide a Content-Disposition header like we would for HTTP.
download: fileName,
target: "_blank",
textContent: "Download " + text,
}, "*");
};
const fileName = content.body && content.body.length > 0 ? content.body : "Attachment";
var downloadAttr = undefined;
if (this.state.decryptedUrl) {
// If the file is encrypted then we MUST download it rather than displaying it
// because Firefox is vunerable to XSS attacks in data:// URLs
// and all browsers are vunerable to XSS attacks in blob: URLs
// created with window.URL.createObjectURL
// See https://bugzilla.mozilla.org/show_bug.cgi?id=255107
// See https://w3c.github.io/FileAPI/#originOfBlobURL
//
// This is not a problem for unencrypted links because they are
// either fetched from a different domain so are safe because of
// the same-origin policy or they are fetch from the same domain,
// in which case we trust that the homeserver will set a
// Content-Security-Policy that disables script execution.
// It is reasonable to trust the homeserver in that case since
// it is the same domain that controls this javascript.
//
// We can't apply the same workaround for encrypted files because
// we can't supply HTTP headers when the user clicks on a blob:
// or data:// uri.
//
// We should probably provide a download attribute anyway so that
// the file will have the correct name when the user tries to
// download it. We can't provide a Content-Disposition header
// like we would for HTTP.
downloadAttr = fileName;
// If the attachment is encryped then put the link inside an iframe.
let renderer_url = DEFAULT_CROSS_ORIGIN_RENDERER;
if (this.context.appConfig && this.context.appConfig.cross_origin_renderer_url) {
renderer_url = this.context.appConfig.cross_origin_renderer_url;
}
if (contentUrl) {
return (
<span className="mx_MFileBody">
<div className="mx_MImageBody_download">
<div style={{display: "none"}}>
{/*
* Add dummy copy of the "a" tag
* We'll use it to learn how the download link
* would have been styled if it was rendered inline.
*/}
<a ref="dummyLink"/>
</div>
<iframe src={renderer_url} onLoad={onIframeLoad} ref="iframe"/>
</div>
</span>
);
} else if (contentUrl) {
// If the attachment is not encrypted then we check whether we
// are being displayed in the room timeline or in a list of
// files in the right hand side of the screen.
if (this.props.tileShape === "file_grid") {
return (
<span className="mx_MFileBody">
<div className="mx_MImageBody_download">
<a className="mx_ImageBody_downloadLink" href={contentUrl} target="_blank" rel="noopener" download={downloadAttr}>
<a className="mx_ImageBody_downloadLink" href={contentUrl} target="_blank">
{ fileName }
</a>
<div className="mx_MImageBody_size">
@ -224,7 +360,7 @@ module.exports = React.createClass({
return (
<span className="mx_MFileBody">
<div className="mx_MImageBody_download">
<a href={contentUrl} target="_blank" rel="noopener" download={downloadAttr}>
<a href={contentUrl} target="_blank" rel="noopener">
<img src={tintedDownloadImageURL} width="12" height="14" ref="downloadImage"/>
Download {text}
</a>

View File

@ -23,7 +23,7 @@ import ImageUtils from '../../../ImageUtils';
import Modal from '../../../Modal';
import sdk from '../../../index';
import dis from '../../../dispatcher';
import {decryptFile} from '../../../utils/DecryptFile';
import { decryptFile, readBlobAsDataUri } from '../../../utils/DecryptFile';
import q from 'q';
module.exports = React.createClass({
@ -41,6 +41,7 @@ module.exports = React.createClass({
return {
decryptedUrl: null,
decryptedThumbnailUrl: null,
decryptedBlob: null,
error: null
};
},
@ -118,13 +119,20 @@ module.exports = React.createClass({
if (content.info.thumbnail_file) {
thumbnailPromise = decryptFile(
content.info.thumbnail_file
);
).then(function (blob) {
return readBlobAsDataUri(blob);
});
}
var decryptedBlob;
thumbnailPromise.then((thumbnailUrl) => {
decryptFile(content.file).then((contentUrl) => {
return decryptFile(content.file).then(function(blob) {
decryptedBlob = blob;
return readBlobAsDataUri(blob);
}).then((contentUrl) => {
this.setState({
decryptedUrl: contentUrl,
decryptedThumbnailUrl: thumbnailUrl,
decryptedBlob: decryptedBlob,
});
this.props.onWidgetLoad();
});
@ -213,7 +221,7 @@ module.exports = React.createClass({
onMouseEnter={this.onImageEnter}
onMouseLeave={this.onImageLeave} />
</a>
<MFileBody {...this.props} decryptedUrl={this.state.decryptedUrl} />
<MFileBody {...this.props} decryptedBlob={this.state.decryptedBlob} />
</span>
);
} else if (content.body) {

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@ -21,7 +21,7 @@ import MFileBody from './MFileBody';
import MatrixClientPeg from '../../../MatrixClientPeg';
import Model from '../../../Modal';
import sdk from '../../../index';
import { decryptFile } from '../../../utils/DecryptFile';
import { decryptFile, readBlobAsDataUri } from '../../../utils/DecryptFile';
import q from 'q';
module.exports = React.createClass({
@ -31,6 +31,7 @@ module.exports = React.createClass({
return {
decryptedUrl: null,
decryptedThumbnailUrl: null,
decryptedBlob: null,
error: null,
};
},
@ -84,13 +85,20 @@ module.exports = React.createClass({
if (content.info.thumbnail_file) {
thumbnailPromise = decryptFile(
content.info.thumbnail_file
);
).then(function(blob) {
return readBlobAsDataUri(blob);
});
}
var decryptedBlob;
thumbnailPromise.then((thumbnailUrl) => {
decryptFile(content.file).then((contentUrl) => {
return decryptFile(content.file).then(function(blob) {
decryptedBlob = blob;
return readBlobAsDataUri(blob);
}).then((contentUrl) => {
this.setState({
decryptedUrl: contentUrl,
decryptedThumbnailUrl: thumbnailUrl,
decryptedBlob: decryptedBlob,
});
});
}).catch((err) => {
@ -159,7 +167,7 @@ module.exports = React.createClass({
controls preload={preload} autoPlay={false}
height={height} width={width} poster={poster}>
</video>
<MFileBody {...this.props} decryptedUrl={this.state.decryptedUrl} />
<MFileBody {...this.props} decryptedBlob={this.state.decryptedBlob} />
</span>
);
},

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@ -27,7 +27,7 @@ import q from 'q';
* Read blob as a data:// URI.
* @return {Promise} A promise that resolves with the data:// URI.
*/
function readBlobAsDataUri(file) {
export function readBlobAsDataUri(file) {
var deferred = q.defer();
var reader = new FileReader();
reader.onload = function(e) {
@ -62,6 +62,6 @@ export function decryptFile(file) {
}).then(function(dataArray) {
// Turn the array into a Blob and give it the correct MIME-type.
var blob = new Blob([dataArray], {type: file.mimetype});
return readBlobAsDataUri(blob);
return blob;
});
}