Our open graph parser logic sloppily mixed data obtained by parsing
open graph properties with trusted data set by our oembed parser.
We fix this by consistenly using our explicit whitelist of generic
properties (image, title, and description) in both places where we
interact with open graph properties. The fixes are redundant with
each other, but doing both helps in making the intent of the code
clearer.
This issue fixed here was originally reported as an XSS vulnerability
in the upcoming Inline URL Previews feature found by Graham Bleaney
and Ibrahim Mohamed using Pysa. The recent Oembed changes close that
vulnerability, but this change is still worth doing to make the
implementation do what it looks like it does.
Modified by punchagan to:
* Replace URLs with titles only if the inline url embed previews are turned on
* Add a test for youtube titles replacing URLs
The titles for the videos are fetched asynchronously after the message has been
sent via the code that fetches metadata for open graph previews. So, the URLs
are replaced with titles only if the inline embed url previews feature is
enabled.
Ideally, YouTube previews should be shown only if inline url previews are
enabled, but this feature is in beta, while YouTube previews are pretty stable.
Once this feature is out of beta, YouTube previews should be shown only if the
url previews feature is turned on.
YouTube preview image is calculated as soon as the message is sent, while the
title needs to be fetched using a network request. This means that the URL is
replaced only after the data has been fetched from the request, and happens a
couple of seconds after the message has been rendered.
Closes#7549
Ensure that the html is safe, before using it. The html is considered if it is
in an iframe with a http/https src, based on the recommendations here:
https://oembed.com/#section3
We directly embed the `iframe` html into the lightbox overlay.
We may be successfully able to get the page once, to get the content type, but
the server or network may go down and cause problems when fetching the page for
parsing its meta tags.
Currently, we only show previews for URLs which are HTML pages, which could
contain other media. We don't show previews for links to non-HTML pages, like
pdf documents or audio/video files. To verify that the URL posted is an HTML
page, we verify the content-type of the page, either using server headers or by
sniffing the content.
Closes#8358
We don't want really long urls to lead to truncated
keys, or we could theoretically have two different
urls get mixed up previews.
Also, this suppresses warnings about exceeding the
250 char limit.
Finally, this gives the key a proper prefix.
We don't have our linter checking test files due to ultra-long strings
that are often present in test output that we verify. But it's worth
at least cleaning out all the ultra-long def lines.
When you edit a message to contain links, and URL previews are
enabled, previously we'd throw an exception, because the realm ID
wasn't included in the event.
Also adds a test so that we can have effective test coverage on this
codepath, though this history is actually that I found the bug through
writing this test :).
We do not use `get_link_embed_data` for messsages sent by
bots, as bots often repeat the same URL over and over again
and are generally either text-focused or have their own
mechanisms to provide preview content.
Fixes#2968.
This change adds support for displaying inline open graph previews for
links posted into Zulip.
It is designed to interact correctly with message editing.
This adds the new settings.INLINE_URL_EMBED_PREVIEW setting to control
whether this feature is enabled.
By default, this setting is currently disabled, so that we can burn it
in for a bit before it impacts users more broadly.
Eventually, we may want to make this manageable via a (set of?)
per-realm settings. E.g. I can imagine a realm wanting to be able to
enable/disable it for certain URLs.
Tim Abbott
Anders Kaseorg
Hariom Verma
Puneeth Chaganti
Anders Kaseorg
Steve Howell
neiljp (Neil Pilgrim)
Nikhil Kumar Mishra
Vishnu Ks
rht
derAnfaenger
Aditya Bansal
Lech Kaiel
Rohitt Vashishtha
Ayush Jain
Steve Howell
Igor Tokarev