docker can't stop containers because of apparmor

[Stephen Buergler]

Docker can't stop containers because it can't send a signal to it because of apparmor. There is also a spelling mistake in the error message.

$ docker stop 35
Error response from daemon: cannot stop container: 35: Cannot kill container 352331e095ca6de50eefaaa4ff3a2b81f056daf71ccb1e2b70a19ea4c1832f5a: unknown error after kill: docker-runc did not terminate sucessfully: container_linux.go:387: signaling init process caused "permission denied"
: unknown
$ dmesg
[1092035.379443] audit: type=1400 audit(1553460324.354:286): apparmor="DENIED" operation="signal" profile="docker-default" pid=15466 comm="docker-runc" requested_mask="receive" denied_mask="receive" signal=kill peer="unconfined"

$ lsb_release -rd
Description: Ubuntu 18.04.2 LTS
Release: 18.04

$ apt-cache policy docker.io
docker.io:
  Installed: 18.09.2-0ubuntu1~18.04.1
  Candidate: 18.09.2-0ubuntu1~18.04.1
  Version table:
 *** 18.09.2-0ubuntu1~18.04.1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
        100 /var/lib/dpkg/status
     18.06.1-0ubuntu1.2~18.04.1 500
        500 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 Packages
     17.12.1-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages

[Michael Hudson-Doyle (mwhudson)]

Hi, this works for me in very simple testing. Can you post a full reproducer?

[Stephen Buergler (sixcorners)]

I think the change in this commit isn't in my app armor profile.
https://github.com/moby/moby/commit/4822fb1e2423d88cdf0ad5d039b8fd3274b05401
What does yours look like?
$ cat /etc/apparmor.d/docker

#include <tunables/global>

profile docker-default flags=(attach_disconnected,mediate_deleted) {

  #include <abstractions/base>

  network,
  capability,
  file,
  umount,

  deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)
  # deny write to files not in /proc/<number>/** or /proc/sys/**
  deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w,
  deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel)
  deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/
  deny @{PROC}/sysrq-trigger rwklx,
  deny @{PROC}/mem rwklx,
  deny @{PROC}/kmem rwklx,
  deny @{PROC}/kcore rwklx,

  deny mount,

  deny /sys/[^f]*/** wklx,
  deny /sys/f[^s]*/** wklx,
  deny /sys/fs/[^c]*/** wklx,
  deny /sys/fs/c[^g]*/** wklx,
  deny /sys/fs/cg[^r]*/** wklx,
  deny /sys/firmware/efi/efivars/** rwklx,
  deny /sys/kernel/security/** rwklx,

  # suppress ptrace denials when using 'docker ps' or using 'ps' inside a container
  ptrace (trace,read) peer=docker-default,

}

[Stephen Buergler (sixcorners)]

It's working now. I'm not sure why.

[Michael Hudson-Doyle (mwhudson)]

Glad it's working now and that's for coming back to report it.