gst-plugin-scanner and browser plugins are used when opening certain emails

Bug #1037669 reported by Jamie Strandboge
262
This bug affects 2 people
Affects Status Importance Assigned to Milestone
Evolution
Fix Released
Medium
evolution (Debian)
New
Undecided
Unassigned
evolution (Ubuntu)
Fix Released
High
Mathieu Trudel-Lapierre
Quantal
Fix Released
High
Mathieu Trudel-Lapierre

Bug Description

Evolution now uses webkit for html mail in 12.10. On launch, it tries to access the google-talkplugin. When looking at a certain messages in preview mode (a google calendar invite), it tries to launch /usr/lib/x86_64-linux-gnu/gstreamer0.10/gstreamer-0.10/gst-plugin-scanner. Interestingly, this is happening even though I have 'Only ever show plain text' configured in Preferences/Mail Preferences/HTML Messages (I do have 'Show suppressed HTML parts as attachments' selected).

This suggests that evolution:
 - would gladly use plugins
 - that javascript is possibly enabled (for the plugin finder)
 - that the WebKit HTML renderer is being invoked even though 'Only ever show plain text' is selected

Webkit is an immensely powerful renderer and it is being used to render completely untrusted input from anyone who can send an email. We need to make sure that plugins and javascript are disabled and that the renderer is not being used at all when 'Only ever show plain text' is enabled (it could be used to deliver text/plain, but it seems that it is processing the HTML then discarding it). This would bring it in line with Thunderbird's policies.

I noticed this because I use AppArmor to confine evolution. Unfortunately in my situation, evolution hung on the message that invoked the plugin finder because the plugin finder failed to launch. I have rules now that will prevent the hang, but evolution isn't handling this error condition gracefully either.

This should be considered an important security regression.

description: updated
Changed in evolution (Ubuntu):
status: New → Confirmed
Revision history for this message
Didier Roche-Tolomelli (didrocks) wrote :

@Mathieu: can you please have a look at this when you have a minute? Can we disable it for release?

Changed in evolution (Ubuntu Quantal):
assignee: nobody → Mathieu Trudel-Lapierre (mathieu-tl)
milestone: none → ubuntu-12.10-beta-2
tags: removed: rls-q-incoming
Changed in evolution (Ubuntu Quantal):
status: Confirmed → In Progress
Revision history for this message
Mathieu Trudel-Lapierre (cyphermox) wrote :

I looked quickly and couldn't figure out a way to fix this decently; looks to me like the actual parsing in webkit is happening in a very different part of the code than the bits that handle whether to show as plain text or not, so fixing this (keeping in mind that plain-text stuff is a module), appears non-trivial.

I opened a bug upstream since we'll need help from the Evolution developers for this one; see https://bugzilla.gnome.org/show_bug.cgi?id=684245

Changed in evolution (Ubuntu Quantal):
status: In Progress → Triaged
Changed in evolution:
importance: Unknown → Medium
status: Unknown → New
Revision history for this message
Jamie Strandboge (jdstrand) wrote :

In case anyone needs it, the profile I use is based on this one:
http://bazaar.launchpad.net/~apparmor-dev/apparmor-profiles/master/view/head:/ubuntu/12.10/usr.bin.evolution

Please note that we are not considering shipping this profile in Ubuntu at this time-- it is something under development and needs a lot more work.

Revision history for this message
Mathieu Trudel-Lapierre (cyphermox) wrote :

Andre linked the following rationale for the current state of Evolution's webkit integration:
https://mail.gnome.org/archives/evolution-list/2012-September/msg00055.html

Changed in evolution (Ubuntu Quantal):
status: Triaged → In Progress
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package evolution - 3.6.0-0ubuntu3

---------------
evolution (3.6.0-0ubuntu3) quantal; urgency=low

  * debian/patches/disable-webkit-plugins.patch: disable all webkit plugins
    when initializing the EWebView (the object that handles displaying messages
    in a message window and in preview), to avoid security issues because of
    these plugins. (LP: #1037669)
  * debian/control: flip the alternative Recommends for spamassassin and
    bogofilter to prefer spamassassin, since bogofilter got demoted.
 -- Mathieu Trudel-Lapierre <email address hidden> Fri, 28 Sep 2012 13:23:53 -0400

Changed in evolution (Ubuntu Quantal):
status: In Progress → Fix Released
Changed in evolution:
status: New → Confirmed
Changed in evolution:
status: Confirmed → Fix Released
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