[Impact]
* The base abstraction in xenial misses some ways programs can push
logs to journald
* Backport the fix form Artful to:
1. get rid of the Denies making logs less readable
2. get users to see the actual log entries will help to unbreak many
other cases
[Test Case]
* Install one of the affected packages (in a xenial container is enough)
* For the case of ntp just install and then run
systemctl restart ntp
* in Dmesg you'll see apparmor Denies like
apparmor="DENIED"
operation="file_inherit"
profile="/usr/sbin/ntpd"
name="/run/systemd/journal/stdout"
* Each case is different, in this (ntp) case also some log entries are
missed due to the block
* After installing the fixed package there is no Deny anymore and
programs are able to correctly log.
[Regression Potential]
* The change is in ubuntu as-is since artful and we are only opening up,
but not limiting the access - so there should be nothing that is denied
after the update that was not before.
Vice versa there could be changes due to things now working correcrly,
but I'd not see that as a regression.
[Other Info]
* affects many packages ntp, tor - I even heard examples of mysql.
But the fix is in apparmor through base abstraction
---
Using tor 0.2.9.9-1ubuntu1 with Linux 4.10.0-9-generic on Zesty, tor fails to start after installing the tor package. "systemctl status tor@default" reports:
Mar 06 16:04:00 zesty systemd[1]: <email address hidden>: Main process exited, code=killed, status=11/SEGV
Mar 06 16:04:00 zesty systemd[1]: Failed to start Anonymizing overlay network for TCP.
Mar 06 16:04:00 zesty systemd[1]: <email address hidden>: Unit entered failed state.
Mar 06 16:04:00 zesty systemd[1]: <email address hidden>: Failed with result 'signal'.
There are two AppArmor denials in the kernel log:
Mar 6 15:53:12 zesty-test kernel: [ 102.699647] audit: type=1400 audit(1488815592.268:35): apparmor="DENIED" operation="file_inherit" namespace="root//lxd-zesty_<var-lib-lxd>" profile="system_tor" name="/run/systemd/journal/stdout" pid=3520 comm="tor" requested_mask="wr" denied_mask="wr" fsuid=100000 ouid=100000
Mar 6 15:53:12 zesty-test kernel: [ 102.702418] audit: type=1400 audit(1488815592.272:37): apparmor="DENIED" operation="file_mmap" namespace="root//lxd-zesty_<var-lib-lxd>" profile="system_tor" name="/usr/bin/tor" pid=3520 comm="tor" requested_mask="m" denied_mask="m" fsuid=100000 ouid=100000
Workaround: add the following two lines to /etc/apparmor.d/system_tor:
/usr/bin/tor m,
/run/systemd/journal/stdout rw,
I couldn't remember how to that that profile reloaded, so I rebooted, and after the reboot tor does start up successfully. "systemctl tor@default" reports it as running.
I haven't checked to see if only one or other rule is actually required.
Importance -> High since this bug makes the package unusable in its default configuration on Zesty. Since the AppArmor profile comes from Debian's 0.2.9.9-1, this should probably be fixed in Debian.
I wonder if "/run/systemd/