#! /usr/bin/python3
# ----------------------------------------------------------------------
#    Copyright (C) 2013 Kshitij Gupta <kgupta8592@gmail.com>
#
#    This program is free software; you can redistribute it and/or
#    modify it under the terms of version 2 of the GNU General Public
#    License as published by the Free Software Foundation.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
# ----------------------------------------------------------------------
import argparse
import atexit
import os
import re
import subprocess
import sys
import time

import apparmor.aa as apparmor
import apparmor.ui as aaui
from apparmor.common import AppArmorException, warn
from apparmor.fail import enable_aa_exception_handler
from apparmor.translations import init_translation

enable_aa_exception_handler()  # setup exception handling
_ = init_translation()  # setup module translations


def sysctl_read(path):
    value = None
    with open(path, 'r') as f_in:
        value = int(f_in.readline())
    return value


def sysctl_write(path, value):
    if value is None:
        warn('Not writing invalid value "None" to %s' % path)
        return
    with open(path, 'w') as f_out:
        f_out.write(str(value))


def last_audit_entry_time():
    out = subprocess.check_output(['tail', '-1', apparmor.logfile])
    logmark = None
    out = out.decode('ascii')
    if re.search(r'^.*msg=audit\((\d+\.\d+:\d+).*\).*$', out):
        logmark = re.search(r'^.*msg=audit\((\d+\.\d+:\d+).*\).*$', out).groups()[0]
    else:
        logmark = ''
    return logmark


def restore_ratelimit():
    try:
        sysctl_write(ratelimit_sysctl, ratelimit_saved)
    except PermissionError:
        if ratelimit_saved != sysctl_read(ratelimit_sysctl):
            raise  # happens only if a) running under lxd and b) something changed the ratelimit since starting aa-genprof


parser = argparse.ArgumentParser(description=_('Generate profile for the given program'))
parser.add_argument('-d', '--dir', type=str, help=_('path to profiles'))
parser.add_argument('-f', '--file', type=str, help=_('path to logfile'))
parser.add_argument('program', type=str, help=_('name of program to profile'))
parser.add_argument('-j', '--json', action="store_true", help=_('Input and Output in JSON'))
parser.add_argument('--no-abstraction', action='store_true', help=_('Do not use any abstractions in profiles'))
parser.add_argument('-o', '--output-dir', type=str, help=_('Output Directory for profiles'))
parser.add_argument('--configdir', type=str, help=argparse.SUPPRESS)
args = parser.parse_args()

profiling = args.program

apparmor.init_aa(confdir=args.configdir, profiledir=args.dir)

if args.json:
    aaui.set_json_mode(apparmor.cfg)
if args.output_dir:
    apparmor.check_output_dir(args.output_dir)
if args.no_abstraction:
    apparmor.disable_abstractions()

apparmor.set_logfile(args.file)

aa_mountpoint = apparmor.check_for_apparmor()
if not aa_mountpoint:
    raise AppArmorException(_('It seems AppArmor was not started. Please enable AppArmor and try again.'))

program = None
# if os.path.exists(apparmor.which(profiling.strip())):
if os.path.exists(profiling):
    program = apparmor.get_full_path(profiling)
else:
    if '/' not in profiling:
        which = apparmor.which(profiling)
        if which:
            program = apparmor.get_full_path(which)

if not program or not os.path.exists(program):
    if '/' not in profiling:
        raise AppArmorException(
            _("Can't find %(profiling)s in the system path list. If the name of the application\n"
              "is correct, please run 'which %(profiling)s' as a user with correct PATH\n"
              "environment set up in order to find the fully-qualified path and\n"
              "use the full path as parameter.")
            % {'profiling': profiling})
    else:
        raise AppArmorException(_('%s does not exists, please double-check the path.') % profiling)

# Check if the program has been marked as not allowed to have a profile
apparmor.check_qualifiers(program)

apparmor.loadincludes()

apparmor.read_profiles(True)

profile_filename = apparmor.get_profile_filename_from_attachment(program, True)
if os.path.exists(profile_filename):
    apparmor.helpers[program] = apparmor.get_profile_flags(profile_filename, program)
else:
    apparmor.autodep(program)
    apparmor.helpers[program] = 'enforce'

if apparmor.helpers[program] == 'enforce':
    apparmor.complain(program)
    apparmor.reload(program)

# When reading from syslog, it is possible to hit the default kernel
# printk ratelimit. This will result in audit entries getting skipped,
# making profile generation inaccurate. When using genprof, disable
# the printk ratelimit, and restore it on exit.
ratelimit_sysctl = '/proc/sys/kernel/printk_ratelimit'
ratelimit_saved = sysctl_read(ratelimit_sysctl)

try:
    sysctl_write(ratelimit_sysctl, 0)
except OSError:  # will fail in lxd
    warn("Can't set printk_ratelimit, some events might be lost")

atexit.register(restore_ratelimit)

aaui.UI_Info(
    _('\nBefore you begin, you may wish to check if a\n'
      'profile already exists for the application you\n'
      'wish to confine. See the following wiki page for\n'
      'more information:') + '\nhttps://gitlab.com/apparmor/apparmor/wikis/Profiles')

syslog = True
logmark = ''
done_profiling = False

if os.path.exists('/var/log/audit/audit.log'):
    syslog = False

while not done_profiling:
    if syslog:
        logmark = 'logmark-%s' % str(int(time.time()))  # unix timestamp, seconds only
        t = subprocess.call([apparmor.logger_path(), '-p', 'kern.warn', 'GenProf: %s' % logmark])

    else:
        logmark = last_audit_entry_time()

    q = aaui.PromptQuestion()
    q.headers = [_('Profiling'), program]
    q.functions = ['CMD_SCAN', 'CMD_FINISHED']
    q.default = 'CMD_SCAN'
    q.explanation = \
        _('Please start the application to be profiled in\n'
          'another window and exercise its functionality now.\n\n'
          'Once completed, select the "Scan" option below in \n'
          'order to scan the system logs for AppArmor events. \n\n'
          'For each AppArmor event, you will be given the \n'
          'opportunity to choose whether the access should be \n'
          'allowed or denied.')
    ans, arg = q.promptUser('noexit')

    if ans == 'CMD_SCAN':
        apparmor.do_logprof_pass(logmark, out_dir=args.output_dir)
    else:
        done_profiling = True

for p in sorted(apparmor.helpers.keys()):
    if apparmor.helpers[p] == 'enforce':
        apparmor.enforce(p)
        apparmor.reload(p)

aaui.UI_Info(_('\nReloaded AppArmor profiles in enforce mode.'))
aaui.UI_Info(_('\nPlease consider contributing your new profile!\n'
               'See the following wiki page for more information:')
             + '\nhttps://gitlab.com/apparmor/apparmor/wikis/Profiles\n')  # noqa: W503
aaui.UI_Info(_('Finished generating profile for %s.') % program)
sys.exit(0)
