aa-genprof should display a clear error message instead of a stack trace if it doesn't have write permissions to the profile directory

[Moshe Kaplan]

When attempting to run aa-genprof, I received the following stack trace:

user@user-desktop:~$ aa-genprof airodump-ng
Writing updated profile for /home/user/aircrack/src/airodump-ng.
Traceback (most recent call last):
  File "/usr/sbin/aa-genprof", line 109, in <module>
    apparmor.autodep(program)
  File "/usr/lib/python3/dist-packages/apparmor/aa.py", line 597, in autodep
    write_profile_ui_feedback(pname)
  File "/usr/lib/python3/dist-packages/apparmor/aa.py", line 4307, in write_profile_ui_feedback
    write_profile(profile)
  File "/usr/lib/python3/dist-packages/apparmor/aa.py", line 4316, in write_profile
    newprof = tempfile.NamedTemporaryFile('w', suffix='~', delete=False, dir=profile_dir)
  File "/usr/lib/python3.4/tempfile.py", line 599, in NamedTemporaryFile
    (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
  File "/usr/lib/python3.4/tempfile.py", line 339, in _mkstemp_inner
    fd = _os.open(file, flags, 0o600)
PermissionError: [Errno 13] Permission denied: '/etc/apparmor.d/tmpj_2nnooj~'

Practically, this was caused by accidentally not running aa-genprof as root. But it would be much more useful for a user if AppArmor instead displayed a helpful error message, like: "Unable to create file in profile directory(%s). Try running aa-genprof as root." % profile_dir

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.