Unable to search in Evince in PDFs opened from Firefox with Firefox AppArmor profile enabled

[Jeremy Nation]

Ubuntu 16.04.2 LTS with Unity
Firefox 51.0.1+build2-0ubuntu0.16.04.2
Evince 3.18.2-1ubuntu4
AppArmor/apparmor-profiles 2.10.95-0ubuntu2.5

Steps to reproduce:

1) Enable AppArmor: service apparmor start
2) Enable Firefox AppArmor profile: aa-enforce /etc/apparmor.d/usr.bin.firefox
3) Reload AppArmor: service apparmor reload
4) Browse to https://help.ubuntu.com/lts/serverguide/serverguide.pdf in Firefox
5) Select "Open with: Document Viewer"
6) Type ctrl-F "Ubuntu"

Expected behavior:
"Ubuntu" appears in the search box at the top and is highlighted in the document.

Observed behavior:
The search box stays empty and nothing is highlighted in the document.

Workarounds:
* Select "Save File" instead of "Open with" and then open the file outside of Firefox with Nautilus, terminal etc
or
* Disable the Firefox AppArmor profile with "aa-disable /etc/apparmor.d/usr.bin.firefox", "service apparmor reload" and then you can search after selecting "Open with".

You may need to restart Firefox and/or Evince after toggling Firefox's AppArmor profile for the changes to take effect.

[Seth Arnold (seth-arnold)]

Hello, thanks for the bug report. Funny, I'd noticed similar with gvim
started via pentadactyl but never noticed AppArmor DENIED messages. Go
figure..

Try adding this line to your /etc/apparmor.d/abstractions/ubuntu-helpers
file, reload the profile and firefox, and please report back if there
are still more issues remaining or not.

  unix (send, receive, connect) peer=(addr="@/tmp/ibus/dbus-????????", label=unconfined),

Thanks

[Jeremy Nation (jnation)]

Adding the "unix..." line to ubuntu-helpers as you suggested fixed the search problem in Evince, thanks. What does that line do? I don't know much about AppArmor.

[Jeremy Nation (jnation)]

Hi Seth, I'd like to get this bug closed one way or another. Can we make a permanent update to the default AppArmor configuration files that Ubuntu provides, or is manually editing /etc/apparmor.d/abstractions/ubuntu-helpers the best fix I can expect for this problem?

[Seth Arnold (seth-arnold)]

I'm sorry I lost track of this. Does anyone have any suggestions on where this line ought to go? In ubuntu-helpers? X? Somewhere else?

Thanks