#!/usr/bin/python -E

#

# Author(s):	Caleb Case <ccase@tresys.com>

#

# Adapted from the bash/awk scripts mkflask.sh and mkaccess_vector.sh

#

import getopt

import os

import sys

import re

class ParseError(Exception):

	def __init__(self, type, file, line):

		self.type = type

		self.file = file

		self.line = line

	def __str__(self):

		typeS = self.type

		if type(self.type) is not str: typeS = Flask.CONSTANT_S[self.type]

		return "Parse Error: Unexpected %s on line %d of %s." % (typeS, self.line, self.file)

class DuplicateError(Exception):

	def __init__(self, type, file, line, symbol):

		self.type = type

		self.file = file

		self.line = line

		self.symbol = symbol

	def __str__(self):

		typeS = self.type

		if type(self.type) is not str: typeS = Flask.CONSTANT_S[self.type]

		return "Duplicate Error: Duplicate %s '%s' on line %d of %s." % (typeS, self.symbol, self.line, self.file)

class UndefinedError(Exception):

	def __init__(self, type, file, line, symbol):

		self.type = type

		self.file = file

		self.line = line

		self.symbol = symbol

	def __str__(self):

		typeS = self.type

		if type(self.type) is not str: typeS = Flask.CONSTANT_S[self.type]

		return "Undefined Error: %s '%s' is not defined but used on line %d of %s." % (typeS, self.symbol, self.line, self.file)

class UnusedError(Exception):

	def __init__(self, info):

		self.info = info

	def __str__(self):

		return "Unused Error: %s" % self.info

class Flask:

	'''

	FLASK container class with utilities for parsing definition

	files and creating c header files.

	'''

	#Constants used in definitions parsing.

	WHITE    = re.compile(r'^\s*$')

	COMMENT  = re.compile(r'^\s*#')

	USERFLAG = re.compile(r'# userspace')

	CLASS    = re.compile(r'^class (?P<name>\w+)')

	COMMON   = re.compile(r'^common (?P<name>\w+)')

	INHERITS = re.compile(r'^inherits (?P<name>\w+)')

	OPENB    = re.compile(r'^{')

	VECTOR   = re.compile(r'^\s*(?P<name>\w+)')

	CLOSEB   = re.compile(r'^}')

	SID      = re.compile(r'^sid (?P<name>\w+)')

	EOF      = "end of file"

	#Constants used in header generation.

	USERSPACE = 0

	KERNEL    = 1

	CONSTANT_S = { \

		#parsing constants

		WHITE    : "whitespace", \

		COMMENT  : "comment", \

		USERFLAG : "userspace flag", \

		CLASS    : "class definition", \

		COMMON   : "common definition", \

		INHERITS : "inherits definition", \

		OPENB    : "'{'", \

		VECTOR   : "access vector definition", \

		CLOSEB   : "'}'", \

		SID      : "security identifier", \

		EOF      : "end of file", \

		#generation constants

		USERSPACE : "userspace mode", \

		KERNEL    : "kernel mode", \

	}

	def __init__(self, warn = True):

		self.WARN = warn

		self.autogen   = "/* This file is automatically generated.  Do not edit. */\n"

		self.commons   = []

		self.user_commons = []

		self.common    = {}

		self.classes   = []

		self.vectors   = []

		self.vector    = {}

		self.userspace = {}

		self.sids      = []

		self.inherits  = {}

	def warning(self, msg):

		'''

		Prints a warning message out to stderr if warnings are enabled.

		'''

		if self.WARN: sys.stderr.write("Warning: %s\n" % msg)

	def parseClasses(self, path):

		'''

		Parses security class definitions from the given path.

		'''

		classes = []

		input = open(path, 'r')

		number = 0

		for line in input:

			number += 1

			m = self.COMMENT.search(line)

			if m: continue

			m = self.WHITE.search(line)

			if m: continue

			m = self.CLASS.search(line)

			if m:

				g = m.groupdict()

				c = g['name']

				if c in classes: raise DuplicateError, (self.CLASS, path, number, c)

				classes.append(c)

				if self.USERFLAG.search(line):

					self.userspace[c] = True

				else:

					self.userspace[c] = False

				continue

			raise ParseError, ("data.  Was expecting either a comment, whitespace, or class definition. ", path, number)

		self.classes = classes

		return classes

	def parseSids(self, path):

		'''

		Parses initial SID definitions from the given path.

		'''

		sids = []

		input = open(path, 'r')

		for line in input:

			m = self.COMMENT.search(line)

			if m: continue

			m = self.WHITE.search(line)

			if m: continue

			m = self.SID.search(line)

			if m:

				g = m.groupdict()

				s = g['name']

				if s in sids: raise DuplicateError, (self.SID, path, number, s)

				sids.append(s)

				continue

			raise ParseError, ("data. Was expecting either a comment, whitespace, or security identifier. ", path, number)

		self.sids = sids

		return sids

	def parseVectors(self, path):

		'''

		Parses access vector definitions from the given path.

		'''

		vectors = []

		vector  = {}

		commons = []

		common = {}

		inherits = {}

		user_commons = {}

		input = open(path, 'r')

		# states

		NONE    = 0

		COMMON  = 1

		CLASS   = 2

		INHERIT = 3

		OPEN    = 4

		state = NONE

		state2 = NONE

		number = 0

		for line in input:

			number += 1

			m = self.COMMENT.search(line)

			if m: continue

			m = self.WHITE.search(line)

			if m: 

				if state == INHERIT:

					state = NONE

				continue

			m = self.COMMON.search(line)

			if m:

				if state != NONE: raise ParseError, (self.COMMON, path, number)

				g = m.groupdict()

				c = g['name']

				if c in commons: raise DuplicateError, (self.COMMON, path, number, c)

				commons.append(c)

				common[c] = []

				user_commons[c] = True

				state = COMMON

				continue

			m = self.CLASS.search(line)

			if m:

				if state != NONE: raise ParseError, (self.CLASS, number)

				g = m.groupdict()

				c = g['name']

				if c in vectors: raise DuplicateError, (self.CLASS, path, number, c)

				if c not in self.classes: raise UndefinedError, (self.CLASS, path, number, c)

				vectors.append(c)

				vector[c] = []

				state = CLASS

				continue

			m = self.INHERITS.search(line)

			if m:

				if state != CLASS: raise ParseError, (self.INHERITS, number)

				g = m.groupdict()

				i = g['name']

				if c in inherits: raise DuplicateError, (self.INHERITS, path, number, c)

				if i not in common: raise UndefinedError, (self.COMMON, path, number, i)

				inherits[c] = i

				state = INHERIT

				if not self.userspace[c]: user_commons[i] = False

				continue

			m = self.OPENB.search(line)

			if m:

				if (state != CLASS \

				and state != INHERIT \

				and state != COMMON) \

				or state2 != NONE: 

					raise ParseError, (self.OPENB, path, number)

				state2 = OPEN

				continue

			m = self.VECTOR.search(line)

			if m:

				if state2 != OPEN: raise ParseError, (self.VECTOR, path, number)

				g = m.groupdict()

				v = g['name']

				if state == CLASS or state == INHERIT:

					if v in vector[c]: raise DuplicateError, (self.VECTOR, path, number, v)

					vector[c].append(v)

				elif state == COMMON:

					if v in common[c]: raise DuplicateError, (self.VECTOR, path, number, v)

					common[c].append(v)

				continue

			m = self.CLOSEB.search(line)

			if m:

				if state2 != OPEN: raise ParseError, (self.CLOSEB, path, number)

				state = NONE

				state2 = NONE

				c = None

				continue

			raise ParseError, ("data", path, number)

		if state != NONE and state2 != NONE: raise ParseError, (self.EOF, path, number)

		cvdiff = set(self.classes) - set(vectors)

		if cvdiff: raise UnusedError, "Not all security classes were used in access vectors: %s" % cvdiff # the inverse of this will be caught as an undefined class error

		self.commons = commons

		self.user_commons = user_commons

		self.common = common

		self.vectors = vectors

		self.vector = vector

		self.inherits = inherits

		return vector

	def createHeaders(self, path, mode = USERSPACE):

		'''

		Creates the C header files in the specified MODE and outputs

		them to give PATH.

		'''

		headers = { \

			'av_inherit.h'            : self.createAvInheritH(mode), \

			'av_perm_to_string.h'     : self.createAvPermToStringH(mode), \

			'av_permissions.h'        : self.createAvPermissionsH(mode), \

			'class_to_string.h'       : self.createClassToStringH(mode), \

			'common_perm_to_string.h' : self.createCommonPermToStringH(mode), \

			'flask.h'                 : self.createFlaskH(mode), \

			'initial_sid_to_string.h' : self.createInitialSidToStringH(mode) \

		}

		for key, value in headers.items():

			of = open(os.path.join(path, key), 'w')

			of.writelines(value)

			of.close()

	def createUL(self, count):

		fields = [1, 2, 4, 8]

		return "0x%08xUL" % (fields[count % 4] << 4 * (count / 4))

	def createAvInheritH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		for c in self.vectors:

			if self.inherits.has_key(c):

				i = self.inherits[c]

				count = len(self.common[i])

				if not (mode == self.KERNEL and self.userspace[c]):

					results.append("   S_(SECCLASS_%s, %s, %s)\n" % (c.upper(), i, self.createUL(count)))

		return results

	def createAvPermToStringH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		for c in self.vectors:

			for p in self.vector[c]:

				if not (mode == self.KERNEL and self.userspace[c]):

					results.append("   S_(SECCLASS_%s, %s__%s, \"%s\")\n" % (c.upper(), c.upper(), p.upper(), p))

		return results

	def createAvPermissionsH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		width = 57

		count = 0

		for common in self.commons:

			count = 0

			shift = 0

			for p in self.common[common]:

				if not (mode == self.KERNEL and self.user_commons[common]):

					columnA = "#define COMMON_%s__%s " % (common.upper(), p.upper())

					columnA += "".join([" " for i in range(width - len(columnA))])

					results.append("%s%s\n" % (columnA, self.createUL(count)))

					count += 1

		width = 50 # broken for old tools whitespace

		for c in self.vectors:

			count = 0

			ps = []

			if self.inherits.has_key(c):

				ps += self.common[self.inherits[c]]

			ps += self.vector[c]

			for p in ps: 

				columnA = "#define %s__%s " % (c.upper(), p.upper())

				columnA += "".join([" " for i in range(width - len(columnA))])

				if not (mode == self.KERNEL and self.userspace[c]):

					results.append("%s%s\n" % (columnA, self.createUL(count)))

				count += 1

		return results

	def createClassToStringH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		results.append("/*\n * Security object class definitions\n */\n")

		if mode == self.KERNEL:

			results.append("    S_(NULL)\n")

		else:

			results.append("    S_(\"null\")\n")

		for c in self.classes:

			if mode == self.KERNEL and self.userspace[c]:

				results.append("    S_(NULL)\n")

			else:

				results.append("    S_(\"%s\")\n" % c)

		return results

	def createCommonPermToStringH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		for common in self.commons:

			if not (mode == self.KERNEL and self.user_commons[common]):

				results.append("TB_(common_%s_perm_to_string)\n" % common)

				for p in self.common[common]:

					results.append("    S_(\"%s\")\n" % p)

				results.append("TE_(common_%s_perm_to_string)\n\n" % common)

		return results

	def createFlaskH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		results.append("#ifndef _SELINUX_FLASK_H_\n")

		results.append("#define _SELINUX_FLASK_H_\n")

		results.append("\n")

		results.append("/*\n")

		results.append(" * Security object class definitions\n")

		results.append(" */\n")

		count = 0

		width = 57

		for c in self.classes:

			count += 1

			columnA = "#define SECCLASS_%s " % c.upper()

			columnA += "".join([" " for i in range(width - len(columnA))])

			if not (mode == self.KERNEL and self.userspace[c]):

				results.append("%s%d\n" % (columnA, count))

		results.append("\n")

		results.append("/*\n")

		results.append(" * Security identifier indices for initial entities\n")

		results.append(" */\n")

		count = 0

		width = 56 # broken for old tools whitespace

		for s in self.sids:

			count += 1

			columnA = "#define SECINITSID_%s " % s.upper()

			columnA += "".join([" " for i in range(width - len(columnA))])

			results.append("%s%d\n" % (columnA, count))

		results.append("\n")

		columnA = "#define SECINITSID_NUM "

		columnA += "".join([" " for i in range(width - len(columnA))])

		results.append("%s%d\n" % (columnA, count))

		results.append("\n")

		results.append("#endif\n")

		return results

	def createInitialSidToStringH(self, mode = USERSPACE):

		'''

		'''

		results = []

		results.append(self.autogen)

		results.append("static char *initial_sid_to_string[] =\n")

		results.append("{\n")

		results.append("    \"null\",\n")

		for s in self.sids:

			results.append("    \"%s\",\n" % s)

		results.append("};\n")

		results.append("\n")

		return results

def usage():

	'''

	Returns the usage string.

	'''

	usage  = 'Usage: %s -a ACCESS_VECTORS -i INITIAL_SIDS -s SECURITY_CLASSES -o OUTPUT_DIRECTORY -k|-u [-w]\n' % os.path.basename(sys.argv[0])

	usage += '\n'

	usage += ' -a --access_vectors\taccess vector definitions\n'

	usage += ' -i --initial_sids\tinitial sid definitions\n'

	usage += ' -s --security_classes\tsecurity class definitions\n'

	usage += ' -o --output\toutput directory for generated files\n'

	usage += ' -k --kernel\toutput mode set to kernel (kernel headers contain empty blocks for all classes specified with # userspace in the security_classes file)\n'

	usage += ' -u --user\toutput mode set to userspace\n'

	usage += ' -w --nowarnings\tsupresses output of warning messages\n'

	return usage

########## MAIN ##########

if __name__ == '__main__':

	# Parse command line args

	try:

		opts, args = getopt.getopt(sys.argv[1:], 'a:i:s:o:kuwh', ['access_vectors=', 'initial_sids=', 'security_classes=', 'output=', 'kernel', 'user', 'nowarnings', 'help'])

	except getopt.GetoptError:

		print(usage())

		sys.exit(2)

	avec = None

	isid = None

	secc = None

	outd = None

	mode = None

	warn = True

	for o, a in opts:

		if o in ('-h', '--help'):

			print(usage())

			sys.exit(0)

		elif o in ('-a', '--access_vectors'):

			avec = a

		elif o in ('-i', '--initial_sids'):

			isid = a

		elif o in ('-s', '--security_classes'):

			secc = a

		elif o in ('-o', '--output'):

			outd = a

		elif o in ('-k', '--kernel'):

			if mode != None:

				print(usage())

				sys.exit(2)

			mode = Flask.KERNEL

		elif o in ('-u', '--user'):

			if mode != None:

				print(usage())

				sys.exit(2)

			mode = Flask.USERSPACE

		elif o in ('-w', '--nowarnings'):

			warn = False

		else:

			print(usage())

			sys.exit(2)

	if avec == None or \

	   isid == None or \

	   secc == None or \

	   outd == None:

		   print(usage())

		   sys.exit(2)

	try:

		f = Flask(warn)

		f.parseSids(isid)

		f.parseClasses(secc)

		f.parseVectors(avec)

		f.createHeaders(outd, mode)

	except Exception, e:

		print(e)

		sys.exit(2)