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[Launchpad Bug Tracker <1387214@xxxxxxxxxxxxxxxxxx>]

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Symptoms are that cache files in /var/cache/apparmor and profiles in
/var/lib/apparmor/profiles are sometimes corrupted after a reboot. We've
already fixed several bugs in the apparmor and click-apparmor and made
both more robust in the face of corruption and we've reduced the impact
when there is a corrupted profile, but we've still not found the cause
of the corruption. This corruption can still affect real-world devices:
if a profile in /var/lib/apparmor/profiles is corrupted and the cache
file is out of date, then the profile won't compile and that app/scope
won't start.

Workaround: remove the affected profile and then run 'sudo aa-
clickhook'. This obviously is not viable on an end-user device.

The investigation is ongoing and this may not be a problem with the
kernel at all, so this bug may be retargeted to another project.

The security team and the kernel team have discussed this a lot and
Colin is currently looking at this. This bug is just so it can be
tracked. Here is an excerpt from my latest email to Colin:

"I believe I have conclusively ruled out apparmor_parser and aa-
clickhook by creating a new 'home/bug/test-with-true.sh'. Here is the
test output:

http://paste.ubuntu.com/8648109/

Specifically, home/bug/test-with-true.sh changes the interesting parts
of the algorithm to:

1. wait for unity8 to start (this ensures the apparmor upstart job is finished)
2. restore apparmor_parser and aa-clickhook, if needed
3. if /home/bug/profiles... exists, perform a diff -Naur /home/bug/profiles...
   /var/lib/apparmor/profiles and fail if differences (note, apparmor_parser
   and aa-clickhook were /bin/true during boot so they could not have changed
   /var/lib/apparmor/profiles)
4. verify the profiles, exit with error if they do not
5. alternately upgrade/downgrade the packages
6. verify the profiles, exit with error if they do not
7. copy the known good profiles in the previous step to /home/bug/profiles...
8. have apparmor_parser and aa-clickhook point to /bin/true
9. reboot
10. go to step 1

In the paste you'll notice that in step 6 the profiles were successfully
created by the installation of the packages, then verified, then copied
aside, then apparmor_parser and aa-clickhook diverted, then rebooted,
only to have the profiles in /var/lib/apparmor/profiles be different
than what was copied aside. It would be nice to verify on your device as
well (I reproduced several times here) and verify the reproducer
algorithm. I think this suggests this is a kernel issue and not
userspace.

IMPORTANT: you will want to update the reproducer and refollow all of these steps (ie, I updated the scripts, the debs, the sudoers file, etc):
$ wget http://people.canonical.com/~jamie/cking/aa-corruption.tar.gz
$ tar -zxvf ./aa-corruption.tar.gz
...

$ adb push ./aa-corruption.tar.gz /tmp
$ adb shell
phablet@ubuntu-phablet:~$ cd /tmp
phablet@ubuntu-phablet:~$ tar -zxvf ./aa-corruption.tar.gz
phablet@ubuntu-phablet:~$ sudo mount -o remount,rw /
phablet@ubuntu-phablet:~$ sudo cp ./aa-corruption/etc/sudoers.d/phablet
/etc/sudoers.d/
phablet@ubuntu-phablet:~$ sudo mount -o remount,ro /
phablet@ubuntu-phablet:~$ sudo cp -a ./aa-corruption/home/bug /home
phablet@ubuntu-phablet:~$ exit
$ cd ./aa-corruption
$ ./test-from-host.sh
...

The old script is still in place. Simply adjust ./test-from-host.sh to have:
testscript=/home/bug/test.sh
#testscript=/home/bug/test-with-true.sh"

The kernel team has verified the above reproducer and symptoms.

Related bugs:
* bug 1371771
* bug 1371765
* bug 1377338

** Affects: system-image (Ubuntu)
     Importance: Critical
     Assignee: Colin Ian King (colin-king)
         Status: Confirmed


** Tags: apparmor application-confinement kernel-key rtm14
-- 
file corruption on touch images in rw portions of the filesystem
https://bugs.launchpad.net/bugs/1387214
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