#!/usr/bin/python
#
# Sets password settings (Password complexity, history length, minimum password
# length, the minimum and maximum password age) on a Samba4 server
#
# Copyright Matthias Dieter Wallnoefer 2009
# Copyright Andrew Kroeger 2009
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# 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.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

import sys

# Find right directory when running from source tree
sys.path.insert(0, "bin/python")

import samba.getopt as options
import optparse
import ldb

from samba.auth import system_session
from samba.samdb import SamDB
from samba.dcerpc.samr import DOMAIN_PASSWORD_COMPLEX

parser = optparse.OptionParser("pwsettings (show | set <options>)")
sambaopts = options.SambaOptions(parser)
parser.add_option_group(sambaopts)
parser.add_option_group(options.VersionOptions(parser))
credopts = options.CredentialsOptions(parser)
parser.add_option_group(credopts)
parser.add_option("--quiet", help="Be quiet", action="store_true")
parser.add_option("--complexity",
  help="The password complexity (on | off | default). Default is 'on'", type=str)
parser.add_option("--history-length",
  help="The password history length (<integer> | default).  Default is 24.", type=str)
parser.add_option("--min-pwd-length",
  help="The minimum password length (<integer> | default).  Default is 7.", type=str)
parser.add_option("--min-pwd-age",
  help="The minimum password age (<integer in days> | default).  Default is 0.", type=str)
parser.add_option("--max-pwd-age",
  help="The maximum password age (<integer in days> | default).  Default is 43.", type=str)

opts, args = parser.parse_args()

#
#  print a message if quiet is not set
#
def message(text):
	if not opts.quiet:
		print text

if len(args) == 0:
	parser.print_usage()
	sys.exit(1)

lp = sambaopts.get_loadparm()
creds = credopts.get_credentials(lp)

samdb = SamDB(url=lp.get("sam database"), session_info=system_session(),
              credentials=creds, lp=lp)

domain_dn = SamDB.domain_dn(samdb)
res = samdb.search(domain_dn, scope=ldb.SCOPE_BASE,
  attrs=["pwdProperties", "pwdHistoryLength", "minPwdLength", "minPwdAge",
  "maxPwdAge"])
assert(len(res) == 1)
try:
	pwd_props = int(res[0]["pwdProperties"][0])
	pwd_hist_len = int(res[0]["pwdHistoryLength"][0])
	min_pwd_len = int(res[0]["minPwdLength"][0])
	# ticks -> days
	min_pwd_age = int(abs(int(res[0]["minPwdAge"][0])) / (1e7 * 60 * 60 * 24))
	max_pwd_age = int(abs(int(res[0]["maxPwdAge"][0])) / (1e7 * 60 * 60 * 24))
except:
	print "ERROR: Could not retrieve password properties!"
	if args[0] == "show":
		print "So no settings can be displayed!"
	sys.exit(1)

if args[0] == "show":
	message("Password informations for domain '" + domain_dn + "'")
	message("")
	if pwd_props & DOMAIN_PASSWORD_COMPLEX != 0:
		message("Password complexity: on")
	else:
		message("Password complexity: off")
	message("Password history length: " + str(pwd_hist_len))
	message("Minimum password length: " + str(min_pwd_len))
	message("Minimum password age (days): " + str(min_pwd_age))
	message("Maximum password age (days): " + str(max_pwd_age))

elif args[0] == "set":

	msgs = []
	m = ldb.Message()
	m.dn = ldb.Dn(samdb, domain_dn)

	if opts.complexity is not None:
		if opts.complexity == "on" or opts.complexity == "default":
			pwd_props = pwd_props | DOMAIN_PASSWORD_COMPLEX
			msgs.append("Password complexity activated!")
		elif opts.complexity == "off":
			pwd_props = pwd_props & (~DOMAIN_PASSWORD_COMPLEX)
			msgs.append("Password complexity deactivated!")
		else:
			print "ERROR: Wrong argument '" + opts.complexity + "'!"
			sys.exit(1)

		m["pwdProperties"] = ldb.MessageElement(str(pwd_props),
		  ldb.FLAG_MOD_REPLACE, "pwdProperties")

	if opts.history_length is not None:
		if opts.history_length == "default":
			pwd_hist_len = 24
		else:
			pwd_hist_len = int(opts.history_length)

		if pwd_hist_len < 0 or pwd_hist_len > 24:
			print "ERROR: Password history length must be in the range of 0 to 24!"
			sys.exit(1)

		m["pwdHistoryLength"] = ldb.MessageElement(str(pwd_hist_len),
		  ldb.FLAG_MOD_REPLACE, "pwdHistoryLength")
		msgs.append("Password history length changed!")

	if opts.min_pwd_length is not None:
		if opts.min_pwd_length == "default":
			min_pwd_len = 7
		else:
			min_pwd_len = int(opts.min_pwd_length)

		if min_pwd_len < 0 or min_pwd_len > 14:
			print "ERROR: Minimum password length must be in the range of 0 to 14!"
			sys.exit(1)

		m["minPwdLength"] = ldb.MessageElement(str(min_pwd_len),
		  ldb.FLAG_MOD_REPLACE, "minPwdLength")
		msgs.append("Minimum password length changed!")

	if opts.min_pwd_age is not None:
		if opts.min_pwd_age == "default":
			min_pwd_age = 0
		else:
			min_pwd_age = int(opts.min_pwd_age)

		if min_pwd_age < 0 or min_pwd_age > 998:
			print "ERROR: Minimum password age must be in the range of 0 to 998!"
			sys.exit(1)

		# days -> ticks
		min_pwd_age_ticks = -int(min_pwd_age * (24 * 60 * 60 * 1e7))

		m["minPwdAge"] = ldb.MessageElement(str(min_pwd_age_ticks),
		  ldb.FLAG_MOD_REPLACE, "minPwdAge")
		msgs.append("Minimum password age changed!")

	if opts.max_pwd_age is not None:
		if opts.max_pwd_age == "default":
			max_pwd_age = 43
		else:
			max_pwd_age = int(opts.max_pwd_age)

		if max_pwd_age < 0 or max_pwd_age > 999:
			print "ERROR: Maximum password age must be in the range of 0 to 999!"
			sys.exit(1)

		# days -> ticks
		max_pwd_age_ticks = -int(max_pwd_age * (24 * 60 * 60 * 1e7))

		m["maxPwdAge"] = ldb.MessageElement(str(max_pwd_age_ticks),
		  ldb.FLAG_MOD_REPLACE, "maxPwdAge")
		msgs.append("Maximum password age changed!")

	if max_pwd_age > 0 and min_pwd_age >= max_pwd_age:
		print "ERROR: Maximum password age (%d) must be greater than minimum password age (%d)!" % (max_pwd_age, min_pwd_age)
		sys.exit(1)

	samdb.modify(m)

	msgs.append("All changes applied successfully!")

	message("\n".join(msgs))
else:
	print "ERROR: Wrong argument '" + args[0] + "'!"
	sys.exit(1)