added python version checks

added startup test to CryptoBox
integrate CryptoBoxRootActions into CryptoBox (see example-super.tab for details)
implemented "mount" and "umount" in CryptoBoxRootActions
adapted CryptoBoxRootActions checks to 'super'

pythonrewrite/bin2/CryptoBox.py

@@ -1,25 +1,36 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2.4
 '''
 This is the web interface for a fileserver managing encrypted filesystems.
  
 It was originally written in bash/perl. Now a complete rewrite is in
 progress. So things might be confusing here. Hopefully not for long.
 :)
+
+
+TODO: replace all "sys.exit"-calls by a unified handler
 '''
 
+# check python version
+import sys
+(ver_major, ver_minor, ver_sub, ver_desc, ver_subsub) = sys.version_info
+if (ver_major < 2) or ((ver_major == 2) and (ver_minor < 4)):
+	sys.stderr.write("You need a python version >= 2.4\nCurrent version is:\n %s\n" % sys.version)
+	sys.exit(1)
+
 import CryptoBoxContainer
 import types
 import re
 import os
-import sys
 import unittest
 import logging
+import subprocess
 
 CONF_LOCATIONS = [
 	"./cryptobox.conf",
 	"~/.cryptobox.conf",
 	"/etc/cryptobox/cryptobox.conf"]
 
+SUDO_WRAPPER = ["sudo", "/home/lars/subversion/cryptobox/branches/pythonrewrite/bin2/CryptoBoxRootActions.py"]
 
 class CryptoBox:
 	'''this class rules them all!
@@ -29,6 +40,7 @@ class CryptoBox:
 	def __init__(self, config_file=None):
 		self.__initLogging()
 		self.__initPreferences(config_file)
+		self.__runTests()
 
 
 	def __initLogging(self):	
@@ -106,19 +118,42 @@ class CryptoBox:
 			if not log_level in log_level_avail:
 				self.log.error("invalid log level: %s is not in %s" % (self.cbxPrefs["Log"]["Level"], log_level_avail))
 				sys.exit(1)
-			self.log.setLevel(getattr(logging, log_level))
-			self.log.addHandler(logging.FileHandler(self.cbxPrefs["Log"]["Details"]))
 		except TypeError:
 			self.log.error("invalid log level: %s" % self.cbxPrefs["Log"]["Level"])
 			sys.exit(1)
+		try:
+			new_handler = logging.FileHandler(self.cbxPrefs["Log"]["Details"])
+			new_handler.setLevel(getattr(logging, log_level))
+			# this formatter does not work for now
+			new_handler.setFormatter = '%(asctime)s %(module)s %(levelname)s %(message)s'
+			self.log.addHandler(new_handler)
 		except IOError:
 			self.log.error("could not open logfile: %s" % self.cbxPrefs["Log"]["Details"])
 			sys.exit(1)
 
 
+	# do some initial checks
+	def __runTests(self):
+		try:
+			devnull = open(os.devnull, "w")
+		except IOError:
+			self.log.error("Could not open %s for writing!" % os.devnull)
+			sys.exit(1)
+		proc = subprocess.Popen(
+			shell = False,
+			stdout = devnull,
+			stderr = devnull,
+			args = [
+				self.cbxPrefs["Programs"]["super"],
+				self.cbxPrefs["Programs"]["CryptoBoxRootActions"],
+				"check"])
+		proc.wait()
+		if proc.returncode != 0:
+			self.log.error("Could not call CryptoBoxRootActions by 'super' - maybe you did not add the appropriate line to /etc/super.tab?")
+			sys.exit(1)
 
-	# RFC: what is this method useful for?
-	# as it claims, just for demonstrating inheritance effects
+
+	# this method just demonstrates inheritance effects - may be removed
 	def cbx_inheritance_test(self):
 		print "you lucky widow"
 

pythonrewrite/bin2/CryptoBoxContainer.py

@@ -1,8 +1,17 @@
-from CryptoBoxLogger import CryptoBoxLogger
-try:
+#!/usr/bin/env python2.4
+
+"""
+TODO: implement "getCapacity"
+"""
+
+# check python version
+import sys
+(ver_major, ver_minor, ver_sub, ver_desc, ver_subsub) = sys.version_info
+if (ver_major < 2) or ((ver_major == 2) and (ver_minor < 4)):
+	sys.stderr.write("You need a python version >= 2.4\nCurrent version is:\n %s\n" % sys.version)
+	sys.exit(1)
+
 import subprocess
-except:
-	print "Couldn't import 'subprocess'. You need a python version >= 2.4"
 import os
 import re
 import logging
@@ -114,10 +123,12 @@ class CryptoBoxContainer:
 			stdout = subprocess.PIPE,
 			stderr = subprocess.PIPE,
 			args = [
-				self.Progs["cryptsetup"],
-				"--batch-mode",
+				self.Progs["super"],
+				self.Progs["CryptoBoxRootActions"],
+				"cryptsetup",
 				"luksAddKey",
-				self.device])
+				self.device,
+				"--batch-mode"])
 		proc.stdin.write("%s\n%s" % (oldpw, newpw))
 		(output, errout) = proc.communicate()
 		if proc.returncode != 0:
@@ -299,11 +310,13 @@ class CryptoBoxContainer:
 			stdout = devnull,
 			stderr = subprocess.PIPE,
 			args = [
-				self.Progs["cryptsetup"],
+				self.Progs["super"],
+				self.Progs["CryptoBoxRootActions"],
+				"cryptsetup",
 				"luksOpen",
-				"--batch-mode",
 				self.device,
-				self.name])
+				self.name,
+				"--batch-mode"])
 		proc.stdin.write(password)
 		(output, errout) = proc.communicate()
 		if proc.returncode != 0:
@@ -316,7 +329,9 @@ class CryptoBoxContainer:
 			stdout = devnull,
 			stderr = subprocess.PIPE,
 			args = [
-				self.Progs["mount"],
+				self.Progs["super"],
+				self.Progs["CryptoBoxRootActions"],
+				"mount",
 				os.path.join(self.__dmDir, self.name),
 				self.__getMountPoint()])
 		proc.wait()
@@ -340,7 +355,11 @@ class CryptoBoxContainer:
 				stdin = None,
 				stdout = devnull,
 				stderr = subprocess.PIPE,
-				args = [self.Progs["umount"], "-l", self.__getMountPoint()])
+				args = [
+					self.Progs["super"],
+					self.Progs["CryptoBoxRootActions"],
+					"umount",
+					self.__getMountPoint()])
 			proc.wait()
 			if proc.returncode != 0:
 				errorMsg = "Could not umount the filesystem: %s" % (proc.stderr.read().strip(), )
@@ -353,10 +372,12 @@ class CryptoBoxContainer:
 				stdout = devnull,
 				stderr = subprocess.PIPE,
 				args = [
-					self.Progs["cryptsetup"],
-					"--batch-mode",
+					self.Progs["super"],
+					self.Progs["CryptoBoxRootActions"],
+					"cryptsetup",
 					"luksClose",
-					self.name])
+					self.name,
+					"--batch-mode"])
 			proc.wait()
 			if proc.returncode != 0:
 				errorMsg = "Could not remove the luks mapping: %s" % (proc.stderr.read().strip(), )
@@ -386,7 +407,9 @@ class CryptoBoxContainer:
 			stdout = devnull,
 			stderr = subprocess.PIPE,
 			args = [
-				self.Progs["mount"],
+				self.Progs["super"],
+				self.Progs["CryptoBoxRootActions"],
+				"mount",
 				self.device,
 				self.__getMountPoint()])
 		proc.wait()
@@ -411,8 +434,9 @@ class CryptoBoxContainer:
 				stdout = devnull,
 				stderr = subprocess.PIPE,
 				args = [
-					self.Progs["umount"],
-					"-l",
+					self.Progs["super"],
+					self.Progs["CryptoBoxRootActions"],
+					"umount",
 					self.__getMountPoint()])
 			proc.wait()
 			if proc.returncode != 0:
@@ -469,12 +493,14 @@ class CryptoBoxContainer:
 			stdout = devnull,
 			stderr = subprocess.PIPE,
 			args = [
-				self.Progs["cryptsetup"],
+				self.Progs["super"],
+				self.Progs["CryptoBoxRootActions"],
+				"cryptsetup",
+				"luksFormat",
+				self.device,
 				"--batch-mode",
 				"--cipher", self.cbox.cbxPrefs["System"]["DefaultCipher"],
-				"--iter-time", "2000",
-				"luksFormat",
-				self.device])
+				"--iter-time", "2000"])
 		proc.stdin.write(password)
 		(output, errout) = proc.communicate()
 		if proc.returncode != 0:
@@ -488,11 +514,13 @@ class CryptoBoxContainer:
 			stdout = devnull,
 			stderr = subprocess.PIPE,
 			args = [
-				self.Progs["cryptsetup"],
-				"--batch-mode",
+				self.Progs["super"],
+				self.Progs["CryptoBoxRootActions"],
+				"cryptsetup",
 				"luksOpen",
 				self.device,
-				self.name])
+				self.name,
+				"--batch-mode"])
 		proc.stdin.write(password)
 		(output, errout) = proc.communicate()
 		if proc.returncode != 0:

pythonrewrite/bin2/CryptoBoxRootActions.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2.4
 """module for executing the programs, that need root privileges
 
 Syntax:
@@ -6,9 +6,9 @@ Syntax:
 	- device
 	- [action]
 	- [action args]
-"""
 
-# current problem: how to identify the "cryptobox" user - to check its permissions?
+this script will always return with an exitcode 0 (true), if "check" is the only argument
+"""
 
 import os
 import sys
@@ -20,24 +20,30 @@ import types
 allowedProgs = {
 	"sfdisk":	"/sbin/sfdisk",
 	"cryptsetup":	"/sbin/cryptsetup",
+	"mount":	"/bin/mount",
+	"umount":	"/bin/umount",
 	}
 
 
-# check if this user has write-access to the device
-allowedUser	= "lars"
-# supply gids - otherwise the default groups of the above user are used
-#allowedGroups	= [6, 1000]
+DEV_TYPES = { "pipe":1, "char":2, "dir":4, "block":6, "file":8, "link":10, "socket":12}
 
 
-def isWriteableBlock(device):
-	fstat = os.stat(device)
-	(dev_type, perm_u, perm_g, perm_o) = (
-		fstat.st_mode % 65536 / 4096,
-		fstat.st_mode % 512 / 64,
-		fstat.st_mode % 512 % 64 / 8,
-		fstat.st_mode % 512 % 64 % 8)
-	(owner_uid, owner_gid) = (fstat.st_uid, fstat.st_gid)
-	(trustUserName, trustUID, groupsOfTrustUser) = getUserInfo(allowedUser)
+def isWriteable(device, force_dev_type=None):
+	"""check if the calling user (not root!) has write access to the device/file
+
+	the real (not the effictive) user id is used for the check
+	additionally the permissions of the default groups of the real uid are checked
+	this check works nicely together with "super", as it changes (by default) only
+	the effective uid (not the real uid)"""
+	# first check, if the device/file exists
+	if not os.path.exists(device):
+		return False
+	# check the type of the device - if necessary
+	if not force_dev_type is None:
+		dev_type = os.stat(device).st_mode % 65536 / 4096
+		if dev_type != force_dev_type: return False
+	# retrieve the information for the real user id
+	(trustUserName, trustUID, groupsOfTrustUser) = getUserInfo(os.getuid())
 	trustGIDs = []
 	try:
 		"if 'allowedGroups' are defined, then ignore the previously aquired groups"
@@ -49,57 +55,72 @@ def isWriteableBlock(device):
 	except TypeError:
 		"if it fails, then 'allowedGroups' was really not well defined"
 		trustGIDs.append(allowedGID)
-	DEF_TYPES = { "pipe":1, "char":2, "dir":4, "block":6, "file":8, "link":10, "socket":12}
-	if dev_type != DEF_TYPES["block"]: return False
-	## could the following check be replaced by os.access?
-	"does the owner id match?"
-	if owner_uid == trustUID:
-		"is the write bit (2) set for the owner?"
-		return perm_u & 2
-	if owner_gid in trustGIDs:
-		return perm_g & 2
-	"we seem to be one of 'others' - so just check the bit"
-	return perm_o & 2
+	# set the default groups of the caller for the check (restore them later)
+	savedGroups = os.getgroups()
+	os.setgroups(trustGIDs)
+	# check permissions
+	result = os.access(device, os.W_OK) and os.access(device, os.R_OK)
+	# reset the groups of this process
+	os.setgroups(savedGroups)
+	return result
 
 
-def run_cryptsetup(device, args):
+def run_cryptsetup(args):
 	"""execute cryptsetup as root
 
 	@args: list of arguments - they will be treated accordingly to the first element
 		of this list (the action)"""
 	if not args: raise "WrongArguments", "no action for cryptsetup supplied"
-	if type(args) != types.ListType: raise "WrongArguments", "invalid arguments supplied"
+	if type(args) != types.ListType: raise "WrongArguments", "invalid arguments supplied: %s" % (args, )
 	try:
 		action = args[0]
 		del args[0]
-		cs_args = [allowedProgs["cryptsetup"]]
-		cs_args.extend(args)
+		device = None
+		cmd_args = []
 		if action == "luksFormat":
-			cs_args.append(action)
-			cs_args.append(device)
+			device = args[0]; del args[0]
+			cmd_args.append(action)
+			cmd_args.append(device)
 		elif action == "luksUUID":
-			cs_args.append(action)
-			cs_args.append(device)
+			device = args[0]; del args[0]
+			cmd_args.append(action)
+			cmd_args.append(device)
 		elif action == "luksOpen":
-			if len(cs_args) < 2: raise "WrongArguments", "missing arguments"
-			cs_args.insert(-1, action)
-			cs_args.insert(-1, device)
+			if len(args) < 2: raise "WrongArguments", "missing arguments"
+			device = args[0]; del args[0]
+			destination = args[0]; del args[0]
+			cmd_args.append(action)
+			cmd_args.append(device)
+			cmd_args.append(destination)
 		elif action == "luksClose":
-			if len(cs_args) < 2: raise "WrongArguments", "missing arguments"
-			cs_args.insert(-1, action)
+			if len(args) < 1: raise "WrongArguments", "missing arguments"
+			destination = args[0]; del args[0]
+			# maybe add a check for the mapped device's permissions?
+			# dmsetup deps self.device
+			cmd_args.append(action)
+			cmd_args.append(destination)
 		elif action == "luksAddKey":
-			cs_args.append(action)
-			cs_args.append(device)
+			device = args[0]; del args[0]
+			cmd_args.append(action)
+			cmd_args.append(device)
 		elif action == "luksDelKey":
 			if len(cs_args) < 2: raise "WrongArguments", "missing arguments"
-			cs_args.insert(-1, action)
-			cs_args.insert(-1, device)
+			device = args[0]; del args[0]
+			cmd_args.insert(-1, action)
+			cmd_args.insert(-1, device)
 		elif action == "isLuks":
-			cs_args.append(action)
-			cs_args.append(device)
-		else: raise "WrongArguments", "invalid action supplied"
-	except TypeError:
-		raise "WrongArguments", "invalid arguments supplied"
+			device = args[0]; del args[0]
+			cmd_args.append(action)
+			cmd_args.append(device)
+		else: raise "WrongArguments", "invalid action supplied: %s" % (action, )
+		# check if a device was defined - and check it
+		if (not device is None) and (not isWriteable(device, DEV_TYPES["block"])):
+			raise "WrongArguments", "%s is not a writeable block device" % (device, )
+		cs_args = [allowedProgs["cryptsetup"]]
+		cs_args.extend(args)
+		cs_args.extend(cmd_args)
+	except (TypeError, IndexError):
+		raise "WrongArguments", "invalid arguments supplied: %s" % (args, )
 	# execute cryptsetup with the given parameters
 	proc = subprocess.Popen(
 		shell = False,
@@ -108,12 +129,78 @@ def run_cryptsetup(device, args):
 	return proc.returncode == 0
 
 
-def run_sfdisk(device, args):
+def run_sfdisk(args):
+	"""execute sfdisk for partitioning
+
+	not implemented yet"""
 	print "ok - you are free to call sfdisk ..."
 	print "  not yet implemented ..."
 	return True
 
 
+def run_mount(args):
+	"""execute mount
+	"""
+	if not args: raise "WrongArguments", "no destination for mount supplied"
+	if type(args) != types.ListType: raise "WrongArguments", "invalid arguments supplied: %s" % (args, )
+	try:
+		device = args[0]
+		del args[0]
+		destination = args[0]
+		del args[0]
+		# check permissions for the device
+		if not isWriteable(device, DEV_TYPES["block"]):
+			raise "WrongArguments", "%s is not a writeable block device" % (device, )
+		# check permissions for the mountpoint
+		if not isWriteable(destination, DEV_TYPES["dir"]):
+			raise "WrongArguments", "the mountpoint (%s) is not writeable" % (destination, )
+		# check for additional (not allowed) arguments
+		if len(args) != 0:
+			raise "WrongArguments", "too many arguments for 'mount': %s" % (args, )
+	except TypeError:
+		raise "WrongArguments", "invalid arguments supplied: %s" % (args, )
+	# execute mount with the given parameters
+	# first overwrite the real uid, as 'mount' wants this to be zero (root)
+	savedUID = os.getuid()
+	os.setuid(os.geteuid())
+	# execute mount
+	proc = subprocess.Popen(
+		shell = False,
+		args = [allowedProgs["mount"], device, destination])
+	proc.communicate()
+	# restore previous real uid
+	os.setuid(savedUID)
+	return proc.returncode == 0
+
+
+def run_umount(args):
+	"""execute mount
+	"""
+	if not args: raise "WrongArguments", "no mountpoint for umount supplied"
+	if type(args) != types.ListType: raise "WrongArguments", "invalid arguments supplied"
+	try:
+		destination = args[0]
+		del args[0]
+		# check permissions for the destination
+		if not isWriteable(destination, DEV_TYPES["dir"]):
+			raise "WrongArguments", "the mountpoint (%s) is not writeable" % (destination, )
+		if len(args) != 0: raise "WrongArguments", "umount does not allow arguments"
+	except TypeError:
+		raise "WrongArguments", "invalid arguments supplied"
+	# execute umount with the given parameters
+	# first overwrite the real uid, as 'umount' wants this to be zero (root)
+	savedUID = os.getuid()
+	os.setuid(os.geteuid())
+	# execute umount (with the parameter '-l' - lazy umount)
+	proc = subprocess.Popen(
+		shell = False,
+		args = [allowedProgs["umount"], "-l", destination])
+	proc.communicate()
+	# restore previous real uid
+	os.setuid(savedUID)
+	return proc.returncode == 0
+
+
 def getUserInfo(user):
 	"""return information about the specified user
 
@@ -139,37 +226,45 @@ def getUserInfo(user):
 # prevent import
 if __name__ == "__main__":
 
+	# do we have root privileges (effective uid is zero)?
+	if os.geteuid() != 0:
+		sys.stderr.write("the effective uid is not zero - you should use 'super' to call this script (%s)" % sys.argv[0])
+		sys.exit(100)
+
 	# remove program name
 	sys.argv.remove(sys.argv[0])
 
+	# do not allow to use root permissions (real uid may not be zero)
+	if os.getuid() == 0:
+		sys.stderr.write("the uid of the caller is zero (root) - this is not allowed\n")
+		sys.exit(100)
+
+	# did the user call the "check" action?
+	if (len(sys.argv) == 1) and (sys.argv[0].lower() == "check"):
+		# exit silently
+		sys.exit(0)
+
+	# check parameters count
 	if len(sys.argv) < 2:
 		sys.stderr.write("Not enough arguments supplied (%s)!\n" % " ".join(sys.argv))
 		sys.exit(100)
 
 	progRequest = sys.argv[0]
-	deviceRequest = sys.argv[1]
-	sys.argv.remove(progRequest)
-	sys.argv.remove(deviceRequest)
+	del sys.argv[0]
 
 	if not progRequest in allowedProgs.keys():
 		sys.stderr.write("Invalid program requested: %s\n" % progRequest)
 		sys.exit(100)
 
-	if not os.path.exists(deviceRequest):
-		sys.stderr.write("The specified device (%s) does not exist!\n" % deviceRequest)
-		sys.exit(100)
-
-	if not isWriteableBlock(deviceRequest):
-		sys.stderr.write("This device (%s) must be a writeable block device!\n" % deviceRequest)
-		sys.exit(100)
-
 	if progRequest == "cryptsetup":	runner = run_cryptsetup
 	elif progRequest == "sfdisk":	runner = run_sfdisk
+	elif progRequest == "mount":	runner = run_mount
+	elif progRequest == "umount":	runner = run_umount
 	else:
 		sys.stderr.write("The interface for this program (%s) is not yet implemented!\n" % progRequest)
 		sys.exit(100)
 	try:
-		if runner(deviceRequest, sys.argv):
+		if runner(sys.argv):
 			sys.exit(0)
 		else:
 			sys.exit(1)

pythonrewrite/bin2/CryptoBoxWebserver.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2.4
 import os,sys
 import CryptoBox
 

pythonrewrite/bin2/cryptobox.conf

@@ -69,4 +69,7 @@ mkfs-config	= /sbin/mkfs.ext2
 blkid		= /sbin/blkid
 mount		= /bin/mount
 umount		= /bin/umount
+super		= /usr/bin/super
+# this is the "program" name as defined in the /etc/super.tab
+CryptoBoxRootActions = CryptoBoxRootActions
 

pythonrewrite/bin2/example-super.tab

@@ -0,0 +1,2 @@
+# adapt the following line to your local setup and add it to /etc/super.tab
+CryptoBoxRootActions	/your/local/path/to/CryptoBoxRootActions.py	yourUserName

pythonrewrite/bin2/test.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python2.4
+
 """
 BEWARE: this script may overwrite the data of one of your loop devices. You
 should restrict the AllowedDevices directive in cryptobox.conf to exclude

pythonrewrite/bin2/unittests.CryptoBox.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python2.4
+
 import unittest
 
 class CryptoBoxPropsDeviceTests(unittest.TestCase):