[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon, 10 Sep 2012 14:48:38 -0600
From: Vincent Danen <vdanen@...hat.com>
To: oss-security@...ts.openwall.com
Cc: Tavis Ormandy <taviso@...xchg8b.com>
Subject: Re: note on gnome shell extensions
* [2012-09-08 18:14:10 -0600] Kurt Seifried wrote:
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>On 09/08/2012 04:36 PM, Tavis Ormandy wrote:
>> List, I just installed Fedora 17 on a workstation. While
>> researching how to upgrade gnome 3 to version 2, I noticed it
>> installed a browser extension called "Gnome Shell Integration".
>>
>> $ rpm -qf
>> /usr/lib64/mozilla/plugins/libgnome-shell-browser-plugin.so
>> gnome-shell-3.4.1-5.fc17.x86_64
>>
>> The NPPVpluginDescriptionString states "It can be used only by
>> extensions.gnome.org", but I happen to know that is a tricky thing
>> to get right.
>
>Erk yeah not good.
>
>> The plugin incorrectly trusted hostname, and initialized. As far as
>> I can tell, the plugin will let you install new shell extensions, I
>> don't know what the impact of that is, can they contain native
>> code?
>>
>> Tavis.
>
>Good news: In theory at least Gnome shell extensions are only
>JavaScript and (optional) CSS using the Gjs bindings, the JavaScript
>itself is run using SpiderMonkey. So no native code execution as far
>as I know.
>
>Bad news: It looks like it has bindings to run command lines from
>within a Gnome Shell Extensions:
>
>http://developer.gnome.org/glibmm/unstable/group__Spawn.html
>http://stackoverflow.com/questions/9606404/gnome-shell-extensions-stdout-from-glib-iochannel
SUSE has some interesting info in their bug:
https://bugzilla.novell.com/show_bug.cgi?id=779473#c4
By the sounds of it, this should be harmless. Vincent Untz says that
the browser plugin doesn't actually install the extensions, it's passed
to another process via a dbus call to gnome-shell, which sends the uuid
of the extension to the extensions.gnome.org web site in order to
download the extension.
See:
http://git.gnome.org/browse/gnome-shell/tree/js/ui/shellDBus.js#n305
http://git.gnome.org/browse/gnome-shell/tree/js/ui/extensionDownloader.js#n27
which is:
let message = Soup.form_request_new_from_hash('GET', REPOSITORY_URL_INFO, params);
And REPOSITORY_URL_INFO is hardcoded earlier:
const REPOSITORY_URL_BASE = 'https://extensions.gnome.org';
const REPOSITORY_URL_DOWNLOAD = REPOSITORY_URL_BASE + '/download-extension/%s.shell-extension.zip';
const REPOSITORY_URL_INFO = REPOSITORY_URL_BASE + '/extension-info/';
const REPOSITORY_URL_UPDATE = REPOSITORY_URL_BASE + '/update-info/';
I don't think this is something that can be exploited, based on the
above.
--
Vincent Danen / Red Hat Security Response Team
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
