#! /usr/bin/env python

# Copyright (C) 2004 Tresys Technology, LLC

# see file 'COPYING' for use and warranty information

#

# genhomedircon - this script is used to generate file context

# configuration entries for user home directories based on their

# default roles and is run when building the policy. Specifically, we

# replace HOME_ROOT, HOME_DIR, and ROLE macros in .fc files with

# generic and user-specific values.

#

# Based off original script by Dan Walsh, <dwalsh@redhat.com>

#

# ASSUMPTIONS:

#

# The file CONTEXTDIR/files/homedir_template exists.  This file is used to

# set up the home directory context for each real user.

# 

# If a user has more than one role in CONTEXTDIR/local.users, genhomedircon uses

#  the first role in the list.

#

# If a user is not listed in CONTEXTDIR/local.users, he will default to user_u, role user

#

# "Real" users (as opposed to system users) are those whose UID is greater than

#  or equal STARTING_UID (usually 500) and whose login is not a member of

#  EXCLUDE_LOGINS.  Users who are explicitly defined in CONTEXTDIR/local.users

#  are always "real" (including root, in the default configuration).

#

#  

# Old ASSUMPTIONS:

#

# If a user has more than one role in FILECONTEXTDIR/users, genhomedircon uses

#  the first role in the list.

#

# If a user is not listed in FILECONTEXTDIR/users, genhomedircon assumes that

#  the user's home dir will be found in one of the HOME_ROOTs.

#

# "Real" users (as opposed to system users) are those whose UID is greater than

#  or equal STARTING_UID (usually 500) and whose login is not a member of

#  EXCLUDE_LOGINS.  Users who are explicitly defined in FILECONTEXTDIR/users

#  are always "real" (including root, in the default configuration).

#

import commands, sys, os, pwd, string, getopt, re

EXCLUDE_LOGINS=["/sbin/nologin", "/bin/false"]

def getStartingUID():

	starting_uid = sys.maxint

	rc=commands.getstatusoutput("grep -h '^UID_MIN' /etc/login.defs")

	if rc[0] == 0:

		uid_min = re.sub("^UID_MIN[^0-9]*", "", rc[1])

		#stip any comment from the end of the line

		uid_min = uid_min.split("#")[0]

		uid_min = uid_min.strip()

		if int(uid_min) < starting_uid:

			starting_uid = int(uid_min)

	rc=commands.getstatusoutput("grep -h '^LU_UIDNUMBER' /etc/libuser.conf")

	if rc[0] == 0:

		lu_uidnumber = re.sub("^LU_UIDNUMBER[^0-9]*", "", rc[1])

		#stip any comment from the end of the line

		lu_uidnumber = re.sub("[ \t].*", "", lu_uidnumber)

		lu_uidnumber = lu_uidnumber.split("#")[0]

		lu_uidnumber = lu_uidnumber.strip()

		if int(lu_uidnumber) < starting_uid:

			starting_uid = int(lu_uidnumber)

	if starting_uid == sys.maxint:

		starting_uid = 500

	return starting_uid

#############################################################################

#

# This section is just for backwards compatability

#

#############################################################################

def getPrefixes():

	ulist = pwd.getpwall()

	STARTING_UID=getStartingUID()

	prefixes = {}

	for u in ulist:

		if u[2] >= STARTING_UID and \

				not u[6] in EXCLUDE_LOGINS and \

				u[5] != "/" and \

				string.count(u[5], "/") > 1:

			prefix = u[5][:string.rfind(u[5], "/")]

			if not prefixes.has_key(prefix):

				prefixes[prefix] = ""

	return prefixes

def getUsers(filecontextdir):

	rc = commands.getstatusoutput("grep ^user %s/users" % filecontextdir)

	udict = {}

	if rc[0] == 0:

		ulist = rc[1].strip().split("\n")

		for u in ulist:

			user = u.split()

			try:

				if user[1] == "user_u" or user[1] == "system_u":

					continue

				# !!! chooses first role in the list to use in the file context !!!

				role = user[3]

				if role == "{":

					role = user[4]

				role = role.split("_r")[0]

				home = pwd.getpwnam(user[1])[5]

				if home == "/":

					continue

				prefs = {}

				prefs["role"] = role

				prefs["home"] = home

				udict[user[1]] = prefs

			except KeyError:

				sys.stderr.write("The user \"%s\" is not present in the passwd file, skipping...\n" % user[1])

	return udict

def update(filecontext, user, prefs):

	rc=commands.getstatusoutput("grep -h '^HOME_DIR' %s | grep -v vmware | sed -e 's|HOME_DIR|%s|' -e 's/ROLE/%s/' -e 's/system_u/%s/'" % (filecontext, prefs["home"], prefs["role"], user))

	if rc[0] == 0:

		print rc[1]

	else:

		errorExit(string.join("grep/sed error ", rc[1]))

	return rc

def oldgenhomedircon(filecontextdir, filecontext):

	sys.stderr.flush()

	if os.path.isdir(filecontextdir) == 0:

		sys.stderr.write("New usage is the following\n")

		usage()

        #We are going to define home directory used by libuser and show-utils as a home directory root

        prefixes = {}

        rc=commands.getstatusoutput("grep -h '^HOME' /etc/default/useradd")

        if rc[0] == 0:

                homedir = rc[1].split("=")[1]

                homedir = homedir.split("#")[0]

                homedir = homedir.strip()

                if not prefixes.has_key(homedir):

                        prefixes[homedir] = ""

        else:

                #rc[0] == 256 means the file was there, we read it, but the grep didn't match

                if rc[0] != 256:

                        sys.stderr.write("%s\n" % rc[1])

                        sys.stderr.write("You do not have access to /etc/default/useradd HOME=\n")

                        sys.stderr.flush()

        rc=commands.getstatusoutput("grep -h '^LU_HOMEDIRECTORY' /etc/libuser.conf")

        if rc[0] == 0:

                homedir = rc[1].split("=")[1]

                homedir = homedir.split("#")[0]

                homedir = homedir.strip()

                homedir = re.sub(r"[^/a-zA-Z0-9].*$", "", homedir)

                if not prefixes.has_key(homedir):

                        prefixes[homedir] = ""

        #the idea is that we need to find all of the home_root_t directories we do this by just accepting

        #any default home directory defined by either /etc/libuser.conf or /etc/default/useradd

        #we then get the potential home directory roots from /etc/passwd or nis or whereever and look at

        #the defined homedir for all users with UID > STARTING_UID.  This list of possible root homedirs

        #is then checked to see if it has an explicite context defined in the file_contexts.  Explicit

        #is any regex that would match it which does not end with .*$ or .+$ since those are general

        #recursive matches.  We then take any regex which ends with [pattern](/.*)?$ and just check against

        #[pattern]

        potential_prefixes = getPrefixes()

        prefix_regex = {}

        #this works by grepping the file_contexts for

        # 1. ^/ makes sure this is not a comment

        # 2. prints only the regex in the first column first cut on \t then on space

        rc=commands.getstatusoutput("grep \"^/\" %s | cut -f 1 | cut -f 1 -d \" \" " %  (sys.argv[2]) )

        if rc[0] == 0:

                prefix_regex = rc[1].split("\n")

        else:

                sys.stderr.write("%s\n" % rc[1])

                sys.stderr.write("You do not have access to grep/cut/the file contexts\n")

                sys.stderr.flush()

        for potential in potential_prefixes.keys():

                addme = 1

                for regex in prefix_regex:

                        #match a trailing (/*)? which is actually a bug in rpc_pipefs

                        regex = re.sub("\(/\*\)\?$", "", regex)

                        #match a trailing .+

                        regex = re.sub("\.+$", "", regex)

                        #match a trailing .*

                        regex = re.sub("\.\*$", "", regex)

                        #strip a (/.*)? which matches anything trailing to a /*$ which matches trailing /'s

                        regex = re.sub("\(\/\.\*\)\?", "", regex)

                        regex = regex + "/*$"

                        if re.search(regex, potential, 0):

                                addme = 0

                if addme == 1:

                        if not prefixes.has_key(potential):

                                prefixes[potential] = ""

        if prefixes.__eq__({}):

                sys.stderr.write("LU_HOMEDIRECTORY not set in /etc/libuser.conf\n")

                sys.stderr.write("HOME= not set in /etc/default/useradd\n")

                sys.stderr.write("And no users with a reasonable homedir found in passwd/nis/ldap/etc...\n")

                sys.stderr.write("Assuming /home is the root of home directories\n")

                sys.stderr.flush()

                prefixes["/home"] = ""

	# There may be a more elegant sed script to expand a macro to multiple lines, but this works

	sed_root = "h; s|^HOME_ROOT|%s|" % (string.join(prefixes.keys(), "|; p; g; s|^HOME_ROOT|"),)

	sed_dir = "h; s|^HOME_DIR|%s/[^/]+|; s|ROLE_|user_|" % (string.join(prefixes.keys(), "/[^/]+|; s|ROLE_|user_|; p; g; s|^HOME_DIR|"),)

	# Fill in HOME_ROOT, HOME_DIR, and ROLE for users not explicitly defined in /etc/security/selinux/src/policy/users

	rc=commands.getstatusoutput("sed -e \"/^HOME_ROOT/{%s}\" -e \"/^HOME_DIR/{%s}\" %s" % (sed_root, sed_dir, filecontext))

	if rc[0] == 0:

		print rc[1]

	else:

		errorExit(string.join("sed error ", rc[1]))

	users = getUsers(filecontextdir)

	print "\n#\n# User-specific file contexts\n#\n"

	# Fill in HOME and ROLE for users that are defined

	for u in users.keys():

		update(filecontext, u, users[u]) 

#############################################################################

#

# End of backwards compatability section

#

#############################################################################

def getDefaultHomeDir():

	ret = []

	rc=commands.getstatusoutput("grep -h '^HOME' /etc/default/useradd")

	if rc[0] == 0:

		homedir = rc[1].split("=")[1]

		homedir = homedir.split("#")[0]

		homedir = homedir.strip()

		if not homedir in ret:

			ret.append(homedir)

	else:

		#rc[0] == 256 means the file was there, we read it, but the grep didn't match

		if rc[0] != 256:

			sys.stderr.write("%s\n" % rc[1])

			sys.stderr.write("You do not have access to /etc/default/useradd HOME=\n")

			sys.stderr.flush()

	rc=commands.getstatusoutput("grep -h '^LU_HOMEDIRECTORY' /etc/libuser.conf")

	if rc[0] == 0:

		homedir = rc[1].split("=")[1]

		homedir = homedir.split("#")[0]

		homedir = homedir.strip()

		if not homedir in ret:

			ret.append(homedir)

	else:

		#rc[0] == 256 means the file was there, we read it, but the grep didn't match

		if rc[0] != 256:

			sys.stderr.write("%s\n" % rc[1])

			sys.stderr.write("You do not have access to /etc/libuser.conf LU_HOMEDIRECTORY=\n")

			sys.stderr.flush()

	if ret == []:

		ret.append("/home")

	return ret

def getSELinuxType(directory):

	rc=commands.getstatusoutput("grep ^SELINUXTYPE= %s/config" % directory)

	if rc[0]==0:

		return rc[1].split("=")[-1].strip()

	return "targeted"

def usage(error = ""):

	if error != "":

		sys.stderr.write("%s\n" % error)

	sys.stderr.write("Usage: %s [ -d selinuxdir ] [-n | --nopasswd] [-t selinuxtype ]\n" % sys.argv[0])

	sys.stderr.flush()

	sys.exit(1)

def warning(warning = ""):

	sys.stderr.write("%s\n" % warning)

	sys.stderr.flush()

def errorExit(error):

	sys.stderr.write("%s exiting for: " % sys.argv[0])

	sys.stderr.write("%s\n" % error)

	sys.stderr.flush()

	sys.exit(1)

class selinuxConfig:

	def __init__(self, selinuxdir="/etc/selinux", type="targeted", usepwd=1):

		self.type=type

		self.selinuxdir=selinuxdir +"/"

		self.contextdir="/contexts"

		self.filecontextdir=self.contextdir+"/files"

		self.usepwd=usepwd

	def getFileContextDir(self):

		return self.selinuxdir+self.type+self.filecontextdir

	def getFileContextFile(self):

		return self.getFileContextDir()+"/file_contexts"

	def getContextDir(self):

		return self.selinuxdir+self.type+self.contextdir

	def getHomeDirTemplate(self):

		return self.getFileContextDir()+"/homedir_template"

	def getHomeRootContext(self, homedir):

		rc=commands.getstatusoutput("grep HOME_ROOT  %s | sed -e \"s|^HOME_ROOT|%s|\"" % ( self.getHomeDirTemplate(), homedir))

		if rc[0] == 0:

			return rc[1]+"\n"

		else:

			errorExit(string.join("sed error ", rc[1]))

	def getUsersFile(self):

		return self.selinuxdir+self.type+"/users/local.users"

	def getSystemUsersFile(self):

		return self.selinuxdir+self.type+"/users/system.users"

	def heading(self):

		ret = "\n#\n#\n# User-specific file contexts, generated via %s\n" % sys.argv[0]

		ret += "# edit %s to change file_context\n#\n#\n" % self.getUsersFile()

		return ret

	def getUsers(self):

		users=""

		rc = commands.getstatusoutput('grep "^user" %s' % self.getSystemUsersFile())

		if rc[0] == 0:

			users+=rc[1]+"\n"

		rc = commands.getstatusoutput("grep ^user %s" % self.getUsersFile())

		if rc[0] == 0:

			users+=rc[1]

		udict = {}

		prefs = {}

		if users != "":

			ulist = users.split("\n")

			for u in ulist:

				user = u.split()

				try:

					if len(user)==0 or user[1] == "user_u" or user[1] == "system_u":

						continue

					# !!! chooses first role in the list to use in the file context !!!

					role = user[3]

					if role == "{":

						role = user[4]

					role = role.split("_r")[0]

					home = pwd.getpwnam(user[1])[5]

					if home == "/":

						continue

					prefs = {}

					prefs["role"] = role

					prefs["home"] = home

					udict[user[1]] = prefs

				except KeyError:

					sys.stderr.write("The user \"%s\" is not present in the passwd file, skipping...\n" % user[1])

		return udict

	def getHomeDirContext(self, user, home, role):

		ret="\n\n#\n# Context for user %s\n#\n\n" % user

		rc=commands.getstatusoutput("grep '^HOME_DIR' %s | sed -e 's|HOME_DIR|%s|' -e 's/ROLE/%s/' -e 's/system_u/%s/'" % (self.getHomeDirTemplate(), home, role, user))

		return ret + rc[1] + "\n"

	def genHomeDirContext(self):

		users = self.getUsers()

		ret=""

		# Fill in HOME and ROLE for users that are defined

		for u in users.keys():

			ret += self.getHomeDirContext (u, users[u]["home"], users[u]["role"])

		return ret+"\n"

	def checkExists(self, home):

		if commands.getstatusoutput("grep -E '^%s[^[:alnum:]_-]' %s" % (home, self.getFileContextFile()))[0] == 0:

			return 0

		#this works by grepping the file_contexts for

		# 1. ^/ makes sure this is not a comment

		# 2. prints only the regex in the first column first cut on \t then on space

		rc=commands.getstatusoutput("grep \"^/\" %s | cut -f 1 | cut -f 1 -d \" \" " %  self.getFileContextFile() )

		if rc[0] == 0:

			prefix_regex = rc[1].split("\n")

		else:

			sys.stderr.write("%s\n" % rc[1])

			sys.stderr.write("You do not have access to grep/cut/the file contexts\n")

			sys.stderr.flush()

		exists=1

		for regex in prefix_regex:

			#match a trailing (/*)? which is actually a bug in rpc_pipefs

			regex = re.sub("\(/\*\)\?$", "", regex)

			#match a trailing .+

			regex = re.sub("\.+$", "", regex)

			#match a trailing .*

			regex = re.sub("\.\*$", "", regex)

			#strip a (/.*)? which matches anything trailing to a /*$ which matches trailing /'s

			regex = re.sub("\(\/\.\*\)\?", "", regex)

			regex = regex + "/*$"

			if re.search(regex, home, 0):

				exists = 0

				break

		if exists == 1:

			return 1

		else:

			return 0

	def getHomeDirs(self):

		homedirs = []

		homedirs = homedirs + getDefaultHomeDir()

		starting_uid=getStartingUID()

		if self.usepwd==0:

			return homedirs

		ulist = pwd.getpwall()

		for u in ulist:

			if u[2] >= starting_uid and \

					not u[6] in EXCLUDE_LOGINS and \

					u[5] != "/" and \

					string.count(u[5], "/") > 1:

				homedir = u[5][:string.rfind(u[5], "/")]

				if not homedir in homedirs:

					if self.checkExists(homedir)==0:

						warning("%s is already defined in %s,\n%s will not create a new context." % (homedir, self.getFileContextFile(), sys.argv[0]))

					else:

						homedirs.append(homedir)

		homedirs.sort()

		return homedirs

	def genoutput(self):

		ret= self.heading()

		for h in self.getHomeDirs():

			ret += self.getHomeDirContext ("user_u" , h+'/[^/]*', "user")

			ret += self.getHomeRootContext(h)

		ret += self.genHomeDirContext()

		return ret

	def printout(self):

		print self.genoutput()

	def write(self):

		try:

			fd = open(self.getFileContextDir()+"/file_contexts.homedirs", "w")

			fd.write(self.genoutput())

			fd.close()

		except IOError, error:

			sys.stderr.write("%s: %s\n" % ( sys.argv[0], error ))

#

# This script will generate home dir file context

# based off the homedir_template file, entries in the password file, and

#

try:

	usepwd=1

	directory="/etc/selinux"

	type=None

	gopts, cmds = getopt.getopt(sys.argv[1:], 'nd:t:', ['help',

						'type=',

						'nopasswd',

						'dir='])

	for o,a in gopts:

		if o == '--type' or o == "-t":

			type=a

		if o == '--nopasswd'  or o == "-n":

			usepwd=0

		if o == '--dir'  or o == "-d":

			directory=a

		if o == '--help':

			usage()

	if type==None:

		type=getSELinuxType(directory)

	if len(cmds) == 2:

		oldgenhomedircon(cmds[0], cmds[1])

		sys.exit(0)

	if len(cmds) != 0:

		usage()

	selconf=selinuxConfig(directory, type, usepwd)

	selconf.write()

except getopt.error, error:

	errorExit(string.join("Options Error ", error))

except ValueError, error:

	errorExit(string.join("ValueError ", error))

except IndexError, error:

	errorExit("IndexError")